js/src/jsapi.h

/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
 * vim: set ts=8 sts=4 et sw=4 tw=99:
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

/* JavaScript API. */

#ifndef jsapi_h
#define jsapi_h

#include "mozilla/AlreadyAddRefed.h"
#include "mozilla/FloatingPoint.h"
#include "mozilla/MemoryReporting.h"
#include "mozilla/Range.h"
#include "mozilla/RangedPtr.h"
#include "mozilla/RefPtr.h"
#include "mozilla/Variant.h"

#include <iterator>
#include <stdarg.h>
#include <stddef.h>
#include <stdint.h>
#include <stdio.h>

#include "jspubtd.h"

#include "js/AllocPolicy.h"
#include "js/CallArgs.h"
#include "js/CharacterEncoding.h"
#include "js/Class.h"
#include "js/GCVector.h"
#include "js/HashTable.h"
#include "js/Id.h"
#include "js/Principals.h"
#include "js/Realm.h"
#include "js/RefCounted.h"
#include "js/RootingAPI.h"
#include "js/Stream.h"
#include "js/TracingAPI.h"
#include "js/UniquePtr.h"
#include "js/Utility.h"
#include "js/Value.h"
#include "js/Vector.h"

/************************************************************************/

namespace JS {

class TwoByteChars;

#ifdef JS_DEBUG

class JS_PUBLIC_API AutoCheckRequestDepth {
  JSContext* cx;

 public:
  explicit AutoCheckRequestDepth(JSContext* cx);
  ~AutoCheckRequestDepth();
};

#define CHECK_REQUEST(cx) JS::AutoCheckRequestDepth _autoCheckRequestDepth(cx)

#else

#define CHECK_REQUEST(cx) ((void)0)

#endif /* JS_DEBUG */

/** AutoValueArray roots an internal fixed-size array of Values. */
template <size_t N>
class MOZ_RAII AutoValueArray : public AutoGCRooter {
  const size_t length_;
  Value elements_[N];

 public:
  explicit AutoValueArray(JSContext* cx MOZ_GUARD_OBJECT_NOTIFIER_PARAM)
      : AutoGCRooter(cx, VALARRAY), length_(N) {
    /* Always initialize in case we GC before assignment. */
    mozilla::PodArrayZero(elements_);
    MOZ_GUARD_OBJECT_NOTIFIER_INIT;
  }

  unsigned length() const { return length_; }
  const Value* begin() const { return elements_; }
  Value* begin() { return elements_; }

  HandleValue operator[](unsigned i) const {
    MOZ_ASSERT(i < N);
    return HandleValue::fromMarkedLocation(&elements_[i]);
  }
  MutableHandleValue operator[](unsigned i) {
    MOZ_ASSERT(i < N);
    return MutableHandleValue::fromMarkedLocation(&elements_[i]);
  }

  MOZ_DECL_USE_GUARD_OBJECT_NOTIFIER
};

using ValueVector = JS::GCVector<JS::Value>;
using IdVector = JS::GCVector<jsid>;
using ScriptVector = JS::GCVector<JSScript*>;
using StringVector = JS::GCVector<JSString*>;

template <class Key, class Value>
class MOZ_RAII AutoHashMapRooter : protected AutoGCRooter {
 private:
  typedef js::HashMap<Key, Value> HashMapImpl;

 public:
  explicit AutoHashMapRooter(JSContext* cx,
                             ptrdiff_t tag MOZ_GUARD_OBJECT_NOTIFIER_PARAM)
      : AutoGCRooter(cx, tag), map(cx) {
    MOZ_GUARD_OBJECT_NOTIFIER_INIT;
  }

  typedef Key KeyType;
  typedef Value ValueType;
  typedef typename HashMapImpl::Entry Entry;
  typedef typename HashMapImpl::Lookup Lookup;
  typedef typename HashMapImpl::Ptr Ptr;
  typedef typename HashMapImpl::AddPtr AddPtr;

  bool init(uint32_t len = 16) { return map.init(len); }
  bool initialized() const { return map.initialized(); }
  Ptr lookup(const Lookup& l) const { return map.lookup(l); }
  void remove(Ptr p) { map.remove(p); }
  AddPtr lookupForAdd(const Lookup& l) const { return map.lookupForAdd(l); }

  template <typename KeyInput, typename ValueInput>
  bool add(AddPtr& p, const KeyInput& k, const ValueInput& v) {
    return map.add(p, k, v);
  }

  bool add(AddPtr& p, const Key& k) { return map.add(p, k); }

  template <typename KeyInput, typename ValueInput>
  bool relookupOrAdd(AddPtr& p, const KeyInput& k, const ValueInput& v) {
    return map.relookupOrAdd(p, k, v);
  }

  typedef typename HashMapImpl::Range Range;
  Range all() const { return map.all(); }

  typedef typename HashMapImpl::Enum Enum;

  void clear() { map.clear(); }

  void finish() { map.finish(); }

  bool empty() const { return map.empty(); }

  uint32_t count() const { return map.count(); }

  size_t capacity() const { return map.capacity(); }

  size_t sizeOfExcludingThis(mozilla::MallocSizeOf mallocSizeOf) const {
    return map.sizeOfExcludingThis(mallocSizeOf);
  }
  size_t sizeOfIncludingThis(mozilla::MallocSizeOf mallocSizeOf) const {
    return map.sizeOfIncludingThis(mallocSizeOf);
  }

  /************************************************** Shorthand operations */

  bool has(const Lookup& l) const { return map.has(l); }

  template <typename KeyInput, typename ValueInput>
  bool put(const KeyInput& k, const ValueInput& v) {
    return map.put(k, v);
  }

  template <typename KeyInput, typename ValueInput>
  bool putNew(const KeyInput& k, const ValueInput& v) {
    return map.putNew(k, v);
  }

  Ptr lookupWithDefault(const Key& k, const Value& defaultValue) {
    return map.lookupWithDefault(k, defaultValue);
  }

  void remove(const Lookup& l) { map.remove(l); }

  friend void AutoGCRooter::trace(JSTracer* trc);

 private:
  AutoHashMapRooter(const AutoHashMapRooter& hmr) = delete;
  AutoHashMapRooter& operator=(const AutoHashMapRooter& hmr) = delete;

  HashMapImpl map;

  MOZ_DECL_USE_GUARD_OBJECT_NOTIFIER
};

template <class T>
class MOZ_RAII AutoHashSetRooter : protected AutoGCRooter {
 private:
  typedef js::HashSet<T> HashSetImpl;

 public:
  explicit AutoHashSetRooter(JSContext* cx,
                             ptrdiff_t tag MOZ_GUARD_OBJECT_NOTIFIER_PARAM)
      : AutoGCRooter(cx, tag), set(cx) {
    MOZ_GUARD_OBJECT_NOTIFIER_INIT;
  }

  typedef typename HashSetImpl::Lookup Lookup;
  typedef typename HashSetImpl::Ptr Ptr;
  typedef typename HashSetImpl::AddPtr AddPtr;

  bool init(uint32_t len = 16) { return set.init(len); }
  bool initialized() const { return set.initialized(); }
  Ptr lookup(const Lookup& l) const { return set.lookup(l); }
  void remove(Ptr p) { set.remove(p); }
  AddPtr lookupForAdd(const Lookup& l) const { return set.lookupForAdd(l); }

  bool add(AddPtr& p, const T& t) { return set.add(p, t); }

  bool relookupOrAdd(AddPtr& p, const Lookup& l, const T& t) {
    return set.relookupOrAdd(p, l, t);
  }

  typedef typename HashSetImpl::Range Range;
  Range all() const { return set.all(); }

  typedef typename HashSetImpl::Enum Enum;

  void clear() { set.clear(); }

  void finish() { set.finish(); }

  bool empty() const { return set.empty(); }

  uint32_t count() const { return set.count(); }

  size_t capacity() const { return set.capacity(); }

  size_t sizeOfExcludingThis(mozilla::MallocSizeOf mallocSizeOf) const {
    return set.sizeOfExcludingThis(mallocSizeOf);
  }
  size_t sizeOfIncludingThis(mozilla::MallocSizeOf mallocSizeOf) const {
    return set.sizeOfIncludingThis(mallocSizeOf);
  }

  /************************************************** Shorthand operations */

  bool has(const Lookup& l) const { return set.has(l); }

  bool put(const T& t) { return set.put(t); }

  bool putNew(const T& t) { return set.putNew(t); }

  void remove(const Lookup& l) { set.remove(l); }

  friend void AutoGCRooter::trace(JSTracer* trc);

 private:
  AutoHashSetRooter(const AutoHashSetRooter& hmr) = delete;
  AutoHashSetRooter& operator=(const AutoHashSetRooter& hmr) = delete;

  HashSetImpl set;

  MOZ_DECL_USE_GUARD_OBJECT_NOTIFIER
};

/**
 * Custom rooting behavior for internal and external clients.
 */
class MOZ_RAII JS_PUBLIC_API CustomAutoRooter : private AutoGCRooter {
 public:
  template <typename CX>
  explicit CustomAutoRooter(const CX& cx MOZ_GUARD_OBJECT_NOTIFIER_PARAM)
      : AutoGCRooter(cx, CUSTOM) {
    MOZ_GUARD_OBJECT_NOTIFIER_INIT;
  }

  friend void AutoGCRooter::trace(JSTracer* trc);

 protected:
  virtual ~CustomAutoRooter() {}

  /** Supplied by derived class to trace roots. */
  virtual void trace(JSTracer* trc) = 0;

 private:
  MOZ_DECL_USE_GUARD_OBJECT_NOTIFIER
};

/** A handle to an array of rooted values. */
class HandleValueArray {
  const size_t length_;
  const Value* const elements_;

  HandleValueArray(size_t len, const Value* elements)
      : length_(len), elements_(elements) {}

 public:
  explicit HandleValueArray(HandleValue value)
      : length_(1), elements_(value.address()) {}

  MOZ_IMPLICIT HandleValueArray(const AutoValueVector& values)
      : length_(values.length()), elements_(values.begin()) {}

  template <size_t N>
  MOZ_IMPLICIT HandleValueArray(const AutoValueArray<N>& values)
      : length_(N), elements_(values.begin()) {}

  /** CallArgs must already be rooted somewhere up the stack. */
  MOZ_IMPLICIT HandleValueArray(const JS::CallArgs& args)
      : length_(args.length()), elements_(args.array()) {}

  /** Use with care! Only call this if the data is guaranteed to be marked. */
  static HandleValueArray fromMarkedLocation(size_t len,
                                             const Value* elements) {
    return HandleValueArray(len, elements);
  }

  static HandleValueArray subarray(const HandleValueArray& values,
                                   size_t startIndex, size_t len) {
    MOZ_ASSERT(startIndex + len <= values.length());
    return HandleValueArray(len, values.begin() + startIndex);
  }

  static HandleValueArray empty() { return HandleValueArray(0, nullptr); }

  size_t length() const { return length_; }
  const Value* begin() const { return elements_; }

  HandleValue operator[](size_t i) const {
    MOZ_ASSERT(i < length_);
    return HandleValue::fromMarkedLocation(&elements_[i]);
  }
};

} /* namespace JS */

/************************************************************************/

struct JSFreeOp {
 protected:
  JSRuntime* runtime_;

  explicit JSFreeOp(JSRuntime* rt) : runtime_(rt) {}

 public:
  JSRuntime* runtime() const {
    MOZ_ASSERT(runtime_);
    return runtime_;
  }
};

/* Callbacks and their arguments. */

/************************************************************************/

typedef bool (*JSInterruptCallback)(JSContext* cx);

typedef JSObject* (*JSGetIncumbentGlobalCallback)(JSContext* cx);

typedef bool (*JSEnqueuePromiseJobCallback)(JSContext* cx, JS::HandleObject job,
                                            JS::HandleObject allocationSite,
                                            JS::HandleObject incumbentGlobal,
                                            void* data);

namespace JS {

enum class PromiseRejectionHandlingState { Unhandled, Handled };

} /* namespace JS */

typedef void (*JSPromiseRejectionTrackerCallback)(
    JSContext* cx, JS::HandleObject promise,
    JS::PromiseRejectionHandlingState state, void* data);

typedef void (*JSProcessPromiseCallback)(JSContext* cx,
                                         JS::HandleObject promise);

/**
 * Possible exception types. These types are part of a JSErrorFormatString
 * structure. They define which error to throw in case of a runtime error.
 *
 * JSEXN_WARN is used for warnings in js.msg files (for instance because we
 * don't want to prepend 'Error:' to warning messages). This value can go away
 * if we ever decide to use an entirely separate mechanism for warnings.
 */
typedef enum JSExnType {
  JSEXN_ERR,
  JSEXN_FIRST = JSEXN_ERR,
  JSEXN_INTERNALERR,
  JSEXN_EVALERR,
  JSEXN_RANGEERR,
  JSEXN_REFERENCEERR,
  JSEXN_SYNTAXERR,
  JSEXN_TYPEERR,
  JSEXN_URIERR,
  JSEXN_DEBUGGEEWOULDRUN,
  JSEXN_WASMCOMPILEERROR,
  JSEXN_WASMLINKERROR,
  JSEXN_WASMRUNTIMEERROR,
  JSEXN_ERROR_LIMIT,
  JSEXN_WARN = JSEXN_ERROR_LIMIT,
  JSEXN_NOTE,
  JSEXN_LIMIT
} JSExnType;

struct JSErrorFormatString {
  /** The error message name in ASCII. */
  const char* name;

  /** The error format string in ASCII. */
  const char* format;

  /** The number of arguments to expand in the formatted error message. */
  uint16_t argCount;

  /** One of the JSExnType constants above. */
  int16_t exnType;
};

typedef const JSErrorFormatString* (*JSErrorCallback)(
    void* userRef, const unsigned errorNumber);

typedef bool (*JSLocaleToUpperCase)(JSContext* cx, JS::HandleString src,
                                    JS::MutableHandleValue rval);

typedef bool (*JSLocaleToLowerCase)(JSContext* cx, JS::HandleString src,
                                    JS::MutableHandleValue rval);

typedef bool (*JSLocaleCompare)(JSContext* cx, JS::HandleString src1,
                                JS::HandleString src2,
                                JS::MutableHandleValue rval);

typedef bool (*JSLocaleToUnicode)(JSContext* cx, const char* src,
                                  JS::MutableHandleValue rval);

/**
 * Callback used to ask the embedding for the cross compartment wrapper handler
 * that implements the desired prolicy for this kind of object in the
 * destination compartment. |obj| is the object to be wrapped. If |existing| is
 * non-nullptr, it will point to an existing wrapper object that should be
 * re-used if possible. |existing| is guaranteed to be a cross-compartment
 * wrapper with a lazily-defined prototype and the correct global. It is
 * guaranteed not to wrap a function.
 */
typedef JSObject* (*JSWrapObjectCallback)(JSContext* cx,
                                          JS::HandleObject existing,
                                          JS::HandleObject obj);

/**
 * Callback used by the wrap hook to ask the embedding to prepare an object
 * for wrapping in a context. This might include unwrapping other wrappers
 * or even finding a more suitable object for the new compartment.
 */
typedef void (*JSPreWrapCallback)(JSContext* cx, JS::HandleObject scope,
                                  JS::HandleObject obj,
                                  JS::HandleObject objectPassedToWrap,
                                  JS::MutableHandleObject retObj);

struct JSWrapObjectCallbacks {
  JSWrapObjectCallback wrap;
  JSPreWrapCallback preWrap;
};

typedef void (*JSDestroyCompartmentCallback)(JSFreeOp* fop,
                                             JSCompartment* compartment);

typedef size_t (*JSSizeOfIncludingThisCompartmentCallback)(
    mozilla::MallocSizeOf mallocSizeOf, JSCompartment* compartment);

typedef void (*JSCompartmentNameCallback)(JSContext* cx,
                                          JSCompartment* compartment, char* buf,
                                          size_t bufsize);

/**
 * Callback used by memory reporting to ask the embedder how much memory an
 * external string is keeping alive.  The embedder is expected to return a value
 * that corresponds to the size of the allocation that will be released by the
 * JSStringFinalizer passed to JS_NewExternalString for this string.
 *
 * Implementations of this callback MUST NOT do anything that can cause GC.
 */
using JSExternalStringSizeofCallback =
    size_t (*)(JSString* str, mozilla::MallocSizeOf mallocSizeOf);

/**
 * Callback used to intercept JavaScript errors.
 */
struct JSErrorInterceptor {
  /**
   * This method is called whenever an error has been raised from JS code.
   *
   * This method MUST be infallible.
   */
  virtual void interceptError(JSContext* cx, const JS::Value& error) = 0;
};

/************************************************************************/

static MOZ_ALWAYS_INLINE JS::Value JS_NumberValue(double d) {
  int32_t i;
  d = JS::CanonicalizeNaN(d);
  if (mozilla::NumberIsInt32(d, &i)) return JS::Int32Value(i);
  return JS::DoubleValue(d);
}

/************************************************************************/

JS_PUBLIC_API bool JS_StringHasBeenPinned(JSContext* cx, JSString* str);

namespace JS {

/**
 * Container class for passing in script source buffers to the JS engine.  This
 * not only groups the buffer and length values, it also provides a way to
 * optionally pass ownership of the buffer to the JS engine without copying.
 * Rules for use:
 *
 *  1) The data array must be allocated with js_malloc() or js_realloc() if
 *     ownership is being granted to the SourceBufferHolder.
 *  2) If ownership is not given to the SourceBufferHolder, then the memory
 *     must be kept alive until the JS compilation is complete.
 *  3) Any code calling SourceBufferHolder::take() must guarantee to keep the
 *     memory alive until JS compilation completes.  Normally only the JS
 *     engine should be calling take().
 *
 * Example use:
 *
 *    size_t length = 512;
 *    char16_t* chars = static_cast<char16_t*>(js_malloc(sizeof(char16_t) *
 * length)); JS::SourceBufferHolder srcBuf(chars, length,
 * JS::SourceBufferHolder::GiveOwnership); JS::Compile(cx, options, srcBuf);
 */
class MOZ_STACK_CLASS SourceBufferHolder final {
 public:
  enum Ownership { NoOwnership, GiveOwnership };

  SourceBufferHolder(const char16_t* data, size_t dataLength,
                     Ownership ownership)
      : data_(data),
        length_(dataLength),
        ownsChars_(ownership == GiveOwnership) {
    // Ensure that null buffers properly return an unowned, empty,
    // null-terminated string.
    static const char16_t NullChar_ = 0;
    if (!get()) {
      data_ = &NullChar_;
      length_ = 0;
      ownsChars_ = false;
    }
  }

  SourceBufferHolder(SourceBufferHolder&& other)
      : data_(other.data_),
        length_(other.length_),
        ownsChars_(other.ownsChars_) {
    other.data_ = nullptr;
    other.length_ = 0;
    other.ownsChars_ = false;
  }

  ~SourceBufferHolder() {
    if (ownsChars_) js_free(const_cast<char16_t*>(data_));
  }

  // Access the underlying source buffer without affecting ownership.
  const char16_t* get() const { return data_; }

  // Length of the source buffer in char16_t code units (not bytes)
  size_t length() const { return length_; }

  // Returns true if the SourceBufferHolder owns the buffer and will free
  // it upon destruction.  If true, it is legal to call take().
  bool ownsChars() const { return ownsChars_; }

  // Retrieve and take ownership of the underlying data buffer.  The caller
  // is now responsible for calling js_free() on the returned value, *but only
  // after JS script compilation has completed*.
  //
  // After the buffer has been taken the SourceBufferHolder functions as if
  // it had been constructed on an unowned buffer;  get() and length() still
  // work.  In order for this to be safe the taken buffer must be kept alive
  // until after JS script compilation completes as noted above.
  //
  // Note, it's the caller's responsibility to check ownsChars() before taking
  // the buffer.  Taking and then free'ing an unowned buffer will have dire
  // consequences.
  char16_t* take() {
    MOZ_ASSERT(ownsChars_);
    ownsChars_ = false;
    return const_cast<char16_t*>(data_);
  }

 private:
  SourceBufferHolder(SourceBufferHolder&) = delete;
  SourceBufferHolder& operator=(SourceBufferHolder&) = delete;

  const char16_t* data_;
  size_t length_;
  bool ownsChars_;
};

struct TranscodeSource;

} /* namespace JS */

/************************************************************************/

/* Property attributes, set in JSPropertySpec and passed to API functions.
 *
 * NB: The data structure in which some of these values are stored only uses
 *     a uint8_t to store the relevant information. Proceed with caution if
 *     trying to reorder or change the the first byte worth of flags.
 */

/* property is visible to for/in loop */
static const uint8_t JSPROP_ENUMERATE = 0x01;

/* not settable: assignment is no-op.  This flag is only valid when neither
   JSPROP_GETTER nor JSPROP_SETTER is set. */
static const uint8_t JSPROP_READONLY = 0x02;

/* property cannot be deleted */
static const uint8_t JSPROP_PERMANENT = 0x04;

/* Passed to JS_Define(UC)Property* and JS_DefineElement if getters/setters are
   JSGetterOp/JSSetterOp */
static const uint8_t JSPROP_PROPOP_ACCESSORS = 0x08;

/* property holds getter function */
static const uint8_t JSPROP_GETTER = 0x10;

/* property holds setter function */
static const uint8_t JSPROP_SETTER = 0x20;

/* internal JS engine use only */
static const uint8_t JSPROP_INTERNAL_USE_BIT = 0x80;

/* native that can be called as a ctor */
static const unsigned JSFUN_CONSTRUCTOR = 0x400;

/* | of all the JSFUN_* flags */
static const unsigned JSFUN_FLAGS_MASK = 0x400;

/*
 * If set, will allow redefining a non-configurable property, but only on a
 * non-DOM global.  This is a temporary hack that will need to go away in bug
 * 1105518.
 */
static const unsigned JSPROP_REDEFINE_NONCONFIGURABLE = 0x1000;

/*
 * Resolve hooks and enumerate hooks must pass this flag when calling
 * JS_Define* APIs to reify lazily-defined properties.
 *
 * JSPROP_RESOLVING is used only with property-defining APIs. It tells the
 * engine to skip the resolve hook when performing the lookup at the beginning
 * of property definition. This keeps the resolve hook from accidentally
 * triggering itself: unchecked recursion.
 *
 * For enumerate hooks, triggering the resolve hook would be merely silly, not
 * fatal, except in some cases involving non-configurable properties.
 */
static const unsigned JSPROP_RESOLVING = 0x2000;

/* ignore the value in JSPROP_ENUMERATE.  This flag only valid when defining
   over an existing property. */
static const unsigned JSPROP_IGNORE_ENUMERATE = 0x4000;

/* ignore the value in JSPROP_READONLY.  This flag only valid when defining over
   an existing property. */
static const unsigned JSPROP_IGNORE_READONLY = 0x8000;

/* ignore the value in JSPROP_PERMANENT.  This flag only valid when defining
   over an existing property. */
static const unsigned JSPROP_IGNORE_PERMANENT = 0x10000;

/* ignore the Value in the descriptor. Nothing was specified when passed to
   Object.defineProperty from script. */
static const unsigned JSPROP_IGNORE_VALUE = 0x20000;

/** Microseconds since the epoch, midnight, January 1, 1970 UTC. */
extern JS_PUBLIC_API int64_t JS_Now(void);

/** Don't want to export data, so provide accessors for non-inline Values. */
extern JS_PUBLIC_API JS::Value JS_GetNaNValue(JSContext* cx);

extern JS_PUBLIC_API JS::Value JS_GetNegativeInfinityValue(JSContext* cx);

extern JS_PUBLIC_API JS::Value JS_GetPositiveInfinityValue(JSContext* cx);

extern JS_PUBLIC_API JS::Value JS_GetEmptyStringValue(JSContext* cx);

extern JS_PUBLIC_API JSString* JS_GetEmptyString(JSContext* cx);

extern JS_PUBLIC_API bool JS_ValueToObject(JSContext* cx, JS::HandleValue v,
                                           JS::MutableHandleObject objp);

extern JS_PUBLIC_API JSFunction* JS_ValueToFunction(JSContext* cx,
                                                    JS::HandleValue v);

extern JS_PUBLIC_API JSFunction* JS_ValueToConstructor(JSContext* cx,
                                                       JS::HandleValue v);

extern JS_PUBLIC_API JSString* JS_ValueToSource(JSContext* cx,
                                                JS::Handle<JS::Value> v);

extern JS_PUBLIC_API bool JS_DoubleIsInt32(double d, int32_t* ip);

extern JS_PUBLIC_API JSType JS_TypeOfValue(JSContext* cx,
                                           JS::Handle<JS::Value> v);

namespace JS {

extern JS_PUBLIC_API const char* InformalValueTypeName(const JS::Value& v);

} /* namespace JS */

extern JS_PUBLIC_API bool JS_StrictlyEqual(JSContext* cx,
                                           JS::Handle<JS::Value> v1,
                                           JS::Handle<JS::Value> v2,
                                           bool* equal);

extern JS_PUBLIC_API bool JS_LooselyEqual(JSContext* cx,
                                          JS::Handle<JS::Value> v1,
                                          JS::Handle<JS::Value> v2,
                                          bool* equal);

extern JS_PUBLIC_API bool JS_SameValue(JSContext* cx, JS::Handle<JS::Value> v1,
                                       JS::Handle<JS::Value> v2, bool* same);

/** True iff fun is the global eval function. */
extern JS_PUBLIC_API bool JS_IsBuiltinEvalFunction(JSFunction* fun);

/** True iff fun is the Function constructor. */
extern JS_PUBLIC_API bool JS_IsBuiltinFunctionConstructor(JSFunction* fun);

/************************************************************************/

/*
 * Locking, contexts, and memory allocation.
 *
 * It is important that SpiderMonkey be initialized, and the first context
 * be created, in a single-threaded fashion.  Otherwise the behavior of the
 * library is undefined.
 * See:
 * https://developer.mozilla.org/en-US/docs/Mozilla/Projects/SpiderMonkey/JSAPI_reference
 */

// Create a new runtime, with a single cooperative context for this thread.
// On success, the new context will be the active context for the runtime.
extern JS_PUBLIC_API JSContext* JS_NewContext(
    uint32_t maxbytes, uint32_t maxNurseryBytes = JS::DefaultNurseryBytes,
    JSRuntime* parentRuntime = nullptr);

// The methods below for controlling the active context in a cooperatively
// multithreaded runtime are not threadsafe, and the caller must ensure they
// are called serially if there is a chance for contention between threads.

// Called from the active context for a runtime, yield execution so that
// this context is no longer active and can no longer use the API.
extern JS_PUBLIC_API void JS_YieldCooperativeContext(JSContext* cx);

// Called from a context whose runtime has no active context, this thread
// becomes the active context for that runtime and may use the API.
extern JS_PUBLIC_API void JS_ResumeCooperativeContext(JSContext* cx);

// Create a new context on this thread for cooperative multithreading in the
// same runtime as siblingContext. Called on a runtime (as indicated by
// siblingContet) which has no active context, on success the new context will
// become the runtime's active context.
extern JS_PUBLIC_API JSContext* JS_NewCooperativeContext(
    JSContext* siblingContext);

namespace JS {

// Class to relinquish exclusive access to all zone groups in use by this
// thread. This allows other cooperative threads to enter the zone groups
// and modify their contents.
struct AutoRelinquishZoneGroups {
  explicit AutoRelinquishZoneGroups(JSContext* cx);
  ~AutoRelinquishZoneGroups();

 private:
  JSContext* cx;
  mozilla::Vector<void*> enterList;
};

}  // namespace JS

// Destroy a context allocated with JS_NewContext or JS_NewCooperativeContext.
// The context must be the current active context in the runtime, and after
// this call the runtime will have no active context.
extern JS_PUBLIC_API void JS_DestroyContext(JSContext* cx);

JS_PUBLIC_API void* JS_GetContextPrivate(JSContext* cx);

JS_PUBLIC_API void JS_SetContextPrivate(JSContext* cx, void* data);

extern JS_PUBLIC_API JSRuntime* JS_GetParentRuntime(JSContext* cx);

extern JS_PUBLIC_API JSRuntime* JS_GetRuntime(JSContext* cx);

extern JS_PUBLIC_API void JS_BeginRequest(JSContext* cx);

extern JS_PUBLIC_API void JS_EndRequest(JSContext* cx);

extern JS_PUBLIC_API void JS_SetFutexCanWait(JSContext* cx);

namespace JS {

// Single threaded execution callbacks are used to notify API clients that a
// feature is in use on a context's runtime that is not yet compatible with
// cooperatively multithreaded execution.
//
// Between a call to BeginSingleThreadedExecutionCallback and a corresponding
// call to EndSingleThreadedExecutionCallback, only one thread at a time may
// enter compartments in the runtime. The begin callback may yield as necessary
// to permit other threads to finish up what they're doing, while the end
// callback may not yield or otherwise operate on the runtime (it may be called
// during GC).
//
// These callbacks may be left unspecified for runtimes which only ever have a
// single context.
typedef void (*BeginSingleThreadedExecutionCallback)(JSContext* cx);
typedef void (*EndSingleThreadedExecutionCallback)(JSContext* cx);

extern JS_PUBLIC_API void SetSingleThreadedExecutionCallbacks(
    JSContext* cx, BeginSingleThreadedExecutionCallback begin,
    EndSingleThreadedExecutionCallback end);

}  // namespace JS

namespace js {

void AssertHeapIsIdle();

} /* namespace js */

class MOZ_RAII JSAutoRequest {
 public:
  explicit JSAutoRequest(JSContext* cx MOZ_GUARD_OBJECT_NOTIFIER_PARAM)
      : mContext(cx) {
    MOZ_GUARD_OBJECT_NOTIFIER_INIT;
    JS_BeginRequest(mContext);
  }
  ~JSAutoRequest() { JS_EndRequest(mContext); }

 protected:
  JSContext* mContext;
  MOZ_DECL_USE_GUARD_OBJECT_NOTIFIER

#if 0
  private:
    static void* operator new(size_t) CPP_THROW_NEW { return 0; }
    static void operator delete(void*, size_t) { }
#endif
};

namespace JS {

class JS_PUBLIC_API ContextOptions {
 public:
  ContextOptions()
      : baseline_(true),
        ion_(true),
        asmJS_(true),
        wasm_(true),
        wasmBaseline_(true),
        wasmIon_(true),
        testWasmAwaitTier2_(false),
        throwOnAsmJSValidationFailure_(false),
        nativeRegExp_(true),
        asyncStack_(true),
        throwOnDebuggeeWouldRun_(true),
        dumpStackOnDebuggeeWouldRun_(false),
        werror_(false),
        strictMode_(false),
        extraWarnings_(false),
        streams_(false)
#ifdef FUZZING
        ,
        fuzzing_(false)
#endif
        ,
        expressionClosures_(false),
        arrayProtoValues_(true) {
  }

  bool baseline() const { return baseline_; }
  ContextOptions& setBaseline(bool flag) {
    baseline_ = flag;
    return *this;
  }
  ContextOptions& toggleBaseline() {
    baseline_ = !baseline_;
    return *this;
  }

  bool ion() const { return ion_; }
  ContextOptions& setIon(bool flag) {
    ion_ = flag;
    return *this;
  }
  ContextOptions& toggleIon() {
    ion_ = !ion_;
    return *this;
  }

  bool asmJS() const { return asmJS_; }
  ContextOptions& setAsmJS(bool flag) {
    asmJS_ = flag;
    return *this;
  }
  ContextOptions& toggleAsmJS() {
    asmJS_ = !asmJS_;
    return *this;
  }

  bool wasm() const { return wasm_; }
  ContextOptions& setWasm(bool flag) {
    wasm_ = flag;
    return *this;
  }
  ContextOptions& toggleWasm() {
    wasm_ = !wasm_;
    return *this;
  }

  bool streams() const { return streams_; }
  ContextOptions& setStreams(bool flag) {
    streams_ = flag;
    return *this;
  }
  ContextOptions& toggleStreams() {
    streams_ = !streams_;
    return *this;
  }

  bool wasmBaseline() const { return wasmBaseline_; }
  ContextOptions& setWasmBaseline(bool flag) {
    wasmBaseline_ = flag;
    return *this;
  }
  ContextOptions& toggleWasmBaseline() {
    wasmBaseline_ = !wasmBaseline_;
    return *this;
  }

  bool wasmIon() const { return wasmIon_; }
  ContextOptions& setWasmIon(bool flag) {
    wasmIon_ = flag;
    return *this;
  }
  ContextOptions& toggleWasmIon() {
    wasmIon_ = !wasmIon_;
    return *this;
  }

  bool testWasmAwaitTier2() const { return testWasmAwaitTier2_; }
  ContextOptions& setTestWasmAwaitTier2(bool flag) {
    testWasmAwaitTier2_ = flag;
    return *this;
  }
  ContextOptions& toggleTestWasmAwaitTier2() {
    testWasmAwaitTier2_ = !testWasmAwaitTier2_;
    return *this;
  }

  bool throwOnAsmJSValidationFailure() const {
    return throwOnAsmJSValidationFailure_;
  }
  ContextOptions& setThrowOnAsmJSValidationFailure(bool flag) {
    throwOnAsmJSValidationFailure_ = flag;
    return *this;
  }
  ContextOptions& toggleThrowOnAsmJSValidationFailure() {
    throwOnAsmJSValidationFailure_ = !throwOnAsmJSValidationFailure_;
    return *this;
  }

  bool nativeRegExp() const { return nativeRegExp_; }
  ContextOptions& setNativeRegExp(bool flag) {
    nativeRegExp_ = flag;
    return *this;
  }

  bool asyncStack() const { return asyncStack_; }
  ContextOptions& setAsyncStack(bool flag) {
    asyncStack_ = flag;
    return *this;
  }

  bool throwOnDebuggeeWouldRun() const { return throwOnDebuggeeWouldRun_; }
  ContextOptions& setThrowOnDebuggeeWouldRun(bool flag) {
    throwOnDebuggeeWouldRun_ = flag;
    return *this;
  }

  bool dumpStackOnDebuggeeWouldRun() const {
    return dumpStackOnDebuggeeWouldRun_;
  }
  ContextOptions& setDumpStackOnDebuggeeWouldRun(bool flag) {
    dumpStackOnDebuggeeWouldRun_ = flag;
    return *this;
  }

  bool werror() const { return werror_; }
  ContextOptions& setWerror(bool flag) {
    werror_ = flag;
    return *this;
  }
  ContextOptions& toggleWerror() {
    werror_ = !werror_;
    return *this;
  }

  bool strictMode() const { return strictMode_; }
  ContextOptions& setStrictMode(bool flag) {
    strictMode_ = flag;
    return *this;
  }
  ContextOptions& toggleStrictMode() {
    strictMode_ = !strictMode_;
    return *this;
  }

  bool extraWarnings() const { return extraWarnings_; }
  ContextOptions& setExtraWarnings(bool flag) {
    extraWarnings_ = flag;
    return *this;
  }
  ContextOptions& toggleExtraWarnings() {
    extraWarnings_ = !extraWarnings_;
    return *this;
  }

#ifdef FUZZING
  bool fuzzing() const { return fuzzing_; }
  ContextOptions& setFuzzing(bool flag) {
    fuzzing_ = flag;
    return *this;
  }
#endif

  bool expressionClosures() const { return expressionClosures_; }
  ContextOptions& setExpressionClosures(bool flag) {
    expressionClosures_ = flag;
    return *this;
  }

  bool arrayProtoValues() const { return arrayProtoValues_; }
  ContextOptions& setArrayProtoValues(bool flag) {
    arrayProtoValues_ = flag;
    return *this;
  }

  void disableOptionsForSafeMode() {
    setBaseline(false);
    setIon(false);
    setAsmJS(false);
    setWasm(false);
    setWasmBaseline(false);
    setWasmIon(false);
    setNativeRegExp(false);
  }

 private:
  bool baseline_ : 1;
  bool ion_ : 1;
  bool asmJS_ : 1;
  bool wasm_ : 1;
  bool wasmBaseline_ : 1;
  bool wasmIon_ : 1;
  bool testWasmAwaitTier2_ : 1;
  bool throwOnAsmJSValidationFailure_ : 1;
  bool nativeRegExp_ : 1;
  bool asyncStack_ : 1;
  bool throwOnDebuggeeWouldRun_ : 1;
  bool dumpStackOnDebuggeeWouldRun_ : 1;
  bool werror_ : 1;
  bool strictMode_ : 1;
  bool extraWarnings_ : 1;
  bool streams_ : 1;
#ifdef FUZZING
  bool fuzzing_ : 1;
#endif
  bool expressionClosures_ : 1;
  bool arrayProtoValues_ : 1;
};

JS_PUBLIC_API ContextOptions& ContextOptionsRef(JSContext* cx);

/**
 * Initialize the runtime's self-hosted code. Embeddings should call this
 * exactly once per runtime/context, before the first JS_NewGlobalObject
 * call.
 */
JS_PUBLIC_API bool InitSelfHostedCode(JSContext* cx);

/**
 * Asserts (in debug and release builds) that `obj` belongs to the current
 * thread's context.
 */
JS_PUBLIC_API void AssertObjectBelongsToCurrentThread(JSObject* obj);

} /* namespace JS */

extern JS_PUBLIC_API const char* JS_GetImplementationVersion(void);

extern JS_PUBLIC_API void JS_SetDestroyCompartmentCallback(
    JSContext* cx, JSDestroyCompartmentCallback callback);

extern JS_PUBLIC_API void JS_SetSizeOfIncludingThisCompartmentCallback(
    JSContext* cx, JSSizeOfIncludingThisCompartmentCallback callback);

extern JS_PUBLIC_API void JS_SetCompartmentNameCallback(
    JSContext* cx, JSCompartmentNameCallback callback);

extern JS_PUBLIC_API void JS_SetWrapObjectCallbacks(
    JSContext* cx, const JSWrapObjectCallbacks* callbacks);

extern JS_PUBLIC_API void JS_SetExternalStringSizeofCallback(
    JSContext* cx, JSExternalStringSizeofCallback callback);

#if defined(NIGHTLY_BUILD)

// Set a callback that will be called whenever an error
// is thrown in this runtime. This is designed as a mechanism
// for logging errors. Note that the VM makes no attempt to sanitize
// the contents of the error (so it may contain private data)
// or to sort out among errors (so it may not be the error you
// are interested in or for the component in which you are
// interested).
//
// If the callback sets a new error, this new error
// will replace the original error.
//
// May be `nullptr`.
extern JS_PUBLIC_API void JS_SetErrorInterceptorCallback(
    JSRuntime*, JSErrorInterceptor* callback);

extern JS_PUBLIC_API JSErrorInterceptor* JS_GetErrorInterceptorCallback(
    JSRuntime*);

// Examine a value to determine if it is one of the built-in Error types.
// If so, return the error type.
extern JS_PUBLIC_API mozilla::Maybe<JSExnType> JS_GetErrorType(
    const JS::Value& val);

#endif  // defined(NIGHTLY_BUILD)

extern JS_PUBLIC_API void JS_SetCompartmentPrivate(JSCompartment* compartment,
                                                   void* data);

extern JS_PUBLIC_API void* JS_GetCompartmentPrivate(JSCompartment* compartment);

extern JS_PUBLIC_API void JS_SetZoneUserData(JS::Zone* zone, void* data);

extern JS_PUBLIC_API void* JS_GetZoneUserData(JS::Zone* zone);

extern JS_PUBLIC_API bool JS_WrapObject(JSContext* cx,
                                        JS::MutableHandleObject objp);

extern JS_PUBLIC_API bool JS_WrapValue(JSContext* cx,
                                       JS::MutableHandleValue vp);

extern JS_PUBLIC_API JSObject* JS_TransplantObject(JSContext* cx,
                                                   JS::HandleObject origobj,
                                                   JS::HandleObject target);

extern JS_PUBLIC_API bool JS_RefreshCrossCompartmentWrappers(
    JSContext* cx, JS::Handle<JSObject*> obj);

/*
 * At any time, a JSContext has a current (possibly-nullptr) compartment.
 * Compartments are described in:
 *
 *   developer.mozilla.org/en-US/docs/SpiderMonkey/SpiderMonkey_compartments
 *
 * The current compartment of a context may be changed. The preferred way to do
 * this is with JSAutoCompartment:
 *
 *   void foo(JSContext* cx, JSObject* obj) {
 *     // in some compartment 'c'
 *     {
 *       JSAutoCompartment ac(cx, obj);  // constructor enters
 *       // in the compartment of 'obj'
 *     }                                 // destructor leaves
 *     // back in compartment 'c'
 *   }
 *
 * For more complicated uses that don't neatly fit in a C++ stack frame, the
 * compartment can entered and left using separate function calls:
 *
 *   void foo(JSContext* cx, JSObject* obj) {
 *     // in 'oldCompartment'
 *     JSCompartment* oldCompartment = JS_EnterCompartment(cx, obj);
 *     // in the compartment of 'obj'
 *     JS_LeaveCompartment(cx, oldCompartment);
 *     // back in 'oldCompartment'
 *   }
 *
 * Note: these calls must still execute in a LIFO manner w.r.t all other
 * enter/leave calls on the context. Furthermore, only the return value of a
 * JS_EnterCompartment call may be passed as the 'oldCompartment' argument of
 * the corresponding JS_LeaveCompartment call.
 *
 * Entering a compartment roots the compartment and its global object for the
 * lifetime of the JSAutoCompartment.
 */

class MOZ_RAII JS_PUBLIC_API JSAutoCompartment {
  JSContext* cx_;
  JSCompartment* oldCompartment_;

 public:
  JSAutoCompartment(JSContext* cx,
                    JSObject* target MOZ_GUARD_OBJECT_NOTIFIER_PARAM);
  JSAutoCompartment(JSContext* cx,
                    JSScript* target MOZ_GUARD_OBJECT_NOTIFIER_PARAM);
  ~JSAutoCompartment();

  MOZ_DECL_USE_GUARD_OBJECT_NOTIFIER
};

class MOZ_RAII JS_PUBLIC_API JSAutoNullableCompartment {
  JSContext* cx_;
  JSCompartment* oldCompartment_;

 public:
  explicit JSAutoNullableCompartment(
      JSContext* cx, JSObject* targetOrNull MOZ_GUARD_OBJECT_NOTIFIER_PARAM);
  ~JSAutoNullableCompartment();

  MOZ_DECL_USE_GUARD_OBJECT_NOTIFIER
};

/** NB: This API is infallible; a nullptr return value does not indicate error.
 *
 * Entering a compartment roots the compartment and its global object until the
 * matching JS_LeaveCompartment() call.
 */
extern JS_PUBLIC_API JSCompartment* JS_EnterCompartment(JSContext* cx,
                                                        JSObject* target);

extern JS_PUBLIC_API void JS_LeaveCompartment(JSContext* cx,
                                              JSCompartment* oldCompartment);

typedef void (*JSIterateCompartmentCallback)(JSContext* cx, void* data,
                                             JSCompartment* compartment);

/**
 * This function calls |compartmentCallback| on every compartment. Beware that
 * there is no guarantee that the compartment will survive after the callback
 * returns. Also, barriers are disabled via the TraceSession.
 */
extern JS_PUBLIC_API void JS_IterateCompartments(
    JSContext* cx, void* data,
    JSIterateCompartmentCallback compartmentCallback);

/**
 * Mark a jsid after entering a new compartment. Different zones separately
 * mark the ids in a runtime, and this must be used any time an id is obtained
 * from one compartment and then used in another compartment, unless the two
 * compartments are guaranteed to be in the same zone.
 */
extern JS_PUBLIC_API void JS_MarkCrossZoneId(JSContext* cx, jsid id);

/**
 * If value stores a jsid (an atomized string or symbol), mark that id as for
 * JS_MarkCrossZoneId.
 */
extern JS_PUBLIC_API void JS_MarkCrossZoneIdValue(JSContext* cx,
                                                  const JS::Value& value);

/**
 * Initialize standard JS class constructors, prototypes, and any top-level
 * functions and constants associated with the standard classes (e.g. isNaN
 * for Number).
 *
 * NB: This sets cx's global object to obj if it was null.
 */
extern JS_PUBLIC_API bool JS_InitStandardClasses(JSContext* cx,
                                                 JS::Handle<JSObject*> obj);

/**
 * Resolve id, which must contain either a string or an int, to a standard
 * class name in obj if possible, defining the class's constructor and/or
 * prototype and storing true in *resolved.  If id does not name a standard
 * class or a top-level property induced by initializing a standard class,
 * store false in *resolved and just return true.  Return false on error,
 * as usual for bool result-typed API entry points.
 *
 * This API can be called directly from a global object class's resolve op,
 * to define standard classes lazily. The class should either have an enumerate
 * hook that calls JS_EnumerateStandardClasses, or a newEnumerate hook that
 * calls JS_NewEnumerateStandardClasses. newEnumerate is preferred because it's
 * faster (does not define all standard classes).
 */
extern JS_PUBLIC_API bool JS_ResolveStandardClass(JSContext* cx,
                                                  JS::HandleObject obj,
                                                  JS::HandleId id,
                                                  bool* resolved);

extern JS_PUBLIC_API bool JS_MayResolveStandardClass(const JSAtomState& names,
                                                     jsid id,
                                                     JSObject* maybeObj);

extern JS_PUBLIC_API bool JS_EnumerateStandardClasses(JSContext* cx,
                                                      JS::HandleObject obj);

extern JS_PUBLIC_API bool JS_NewEnumerateStandardClasses(
    JSContext* cx, JS::HandleObject obj, JS::AutoIdVector& properties,
    bool enumerableOnly);

extern JS_PUBLIC_API bool JS_GetClassObject(JSContext* cx, JSProtoKey key,
                                            JS::MutableHandle<JSObject*> objp);

extern JS_PUBLIC_API bool JS_GetClassPrototype(
    JSContext* cx, JSProtoKey key, JS::MutableHandle<JSObject*> objp);

namespace JS {

/*
 * Determine if the given object is an instance/prototype/constructor for a
 * standard class. If so, return the associated JSProtoKey. If not, return
 * JSProto_Null.
 */

extern JS_PUBLIC_API JSProtoKey IdentifyStandardInstance(JSObject* obj);

extern JS_PUBLIC_API JSProtoKey IdentifyStandardPrototype(JSObject* obj);

extern JS_PUBLIC_API JSProtoKey
IdentifyStandardInstanceOrPrototype(JSObject* obj);

extern JS_PUBLIC_API JSProtoKey IdentifyStandardConstructor(JSObject* obj);

extern JS_PUBLIC_API void ProtoKeyToId(JSContext* cx, JSProtoKey key,
                                       JS::MutableHandleId idp);

} /* namespace JS */

extern JS_PUBLIC_API JSProtoKey JS_IdToProtoKey(JSContext* cx, JS::HandleId id);

/**
 * Returns the original value of |Function.prototype| from the global object in
 * which |forObj| was created.
 */
extern JS_PUBLIC_API JSObject* JS_GetFunctionPrototype(JSContext* cx,
                                                       JS::HandleObject forObj);

/**
 * Returns the original value of |Object.prototype| from the global object in
 * which |forObj| was created.
 */
extern JS_PUBLIC_API JSObject* JS_GetObjectPrototype(JSContext* cx,
                                                     JS::HandleObject forObj);

/**
 * Returns the original value of |Array.prototype| from the global object in
 * which |forObj| was created.
 */
extern JS_PUBLIC_API JSObject* JS_GetArrayPrototype(JSContext* cx,
                                                    JS::HandleObject forObj);

/**
 * Returns the original value of |Error.prototype| from the global
 * object of the current compartment of cx.
 */
extern JS_PUBLIC_API JSObject* JS_GetErrorPrototype(JSContext* cx);

/**
 * Returns the %IteratorPrototype% object that all built-in iterator prototype
 * chains go through for the global object of the current compartment of cx.
 */
extern JS_PUBLIC_API JSObject* JS_GetIteratorPrototype(JSContext* cx);

extern JS_PUBLIC_API JSObject* JS_GetGlobalForObject(JSContext* cx,
                                                     JSObject* obj);

extern JS_PUBLIC_API bool JS_IsGlobalObject(JSObject* obj);

extern JS_PUBLIC_API JSObject* JS_GlobalLexicalEnvironment(JSObject* obj);

extern JS_PUBLIC_API bool JS_HasExtensibleLexicalEnvironment(JSObject* obj);

extern JS_PUBLIC_API JSObject* JS_ExtensibleLexicalEnvironment(JSObject* obj);

/**
 * May return nullptr, if |c| never had a global (e.g. the atoms compartment),
 * or if |c|'s global has been collected.
 */
extern JS_PUBLIC_API JSObject* JS_GetGlobalForCompartmentOrNull(
    JSContext* cx, JSCompartment* c);

namespace JS {

extern JS_PUBLIC_API JSObject* CurrentGlobalOrNull(JSContext* cx);

}  // namespace JS

/**
 * Add 'Reflect.parse', a SpiderMonkey extension, to the Reflect object on the
 * given global.
 */
extern JS_PUBLIC_API bool JS_InitReflectParse(JSContext* cx,
                                              JS::HandleObject global);

/**
 * Add various profiling-related functions as properties of the given object.
 * Defined in builtin/Profilers.cpp.
 */
extern JS_PUBLIC_API bool JS_DefineProfilingFunctions(JSContext* cx,
                                                      JS::HandleObject obj);

/* Defined in vm/Debugger.cpp. */
extern JS_PUBLIC_API bool JS_DefineDebuggerObject(JSContext* cx,
                                                  JS::HandleObject obj);

#ifdef JS_HAS_CTYPES
/**
 * Initialize the 'ctypes' object on a global variable 'obj'. The 'ctypes'
 * object will be sealed.
 */
extern JS_PUBLIC_API bool JS_InitCTypesClass(JSContext* cx,
                                             JS::HandleObject global);

/**
 * Convert a unicode string 'source' of length 'slen' to the platform native
 * charset, returning a null-terminated string allocated with JS_malloc. On
 * failure, this function should report an error.
 */
typedef char* (*JSCTypesUnicodeToNativeFun)(JSContext* cx,
                                            const char16_t* source,
                                            size_t slen);

/**
 * Set of function pointers that ctypes can use for various internal functions.
 * See JS_SetCTypesCallbacks below. Providing nullptr for a function is safe,
 * and will result in the applicable ctypes functionality not being available.
 */
struct JSCTypesCallbacks {
  JSCTypesUnicodeToNativeFun unicodeToNative;
};

/**
 * Set the callbacks on the provided 'ctypesObj' object. 'callbacks' should be a
 * pointer to static data that exists for the lifetime of 'ctypesObj', but it
 * may safely be altered after calling this function and without having
 * to call this function again.
 */
extern JS_PUBLIC_API void JS_SetCTypesCallbacks(
    JSObject* ctypesObj, const JSCTypesCallbacks* callbacks);
#endif

extern JS_PUBLIC_API void* JS_malloc(JSContext* cx, size_t nbytes);

extern JS_PUBLIC_API void* JS_realloc(JSContext* cx, void* p, size_t oldBytes,
                                      size_t newBytes);

/**
 * A wrapper for js_free(p) that may delay js_free(p) invocation as a
 * performance optimization.
 * cx may be nullptr.
 */
extern JS_PUBLIC_API void JS_free(JSContext* cx, void* p);

/**
 * A wrapper for js_free(p) that may delay js_free(p) invocation as a
 * performance optimization as specified by the given JSFreeOp instance.
 */
extern JS_PUBLIC_API void JS_freeop(JSFreeOp* fop, void* p);

extern JS_PUBLIC_API void JS_updateMallocCounter(JSContext* cx, size_t nbytes);

extern JS_PUBLIC_API char* JS_strdup(JSContext* cx, const char* s);

/**
 * Set the size of the native stack that should not be exceed. To disable
 * stack size checking pass 0.
 *
 * SpiderMonkey allows for a distinction between system code (such as GCs, which
 * may incidentally be triggered by script but are not strictly performed on
 * behalf of such script), trusted script (as determined by
 * JS_SetTrustedPrincipals), and untrusted script. Each kind of code may have a
 * different stack quota, allowing embedders to keep higher-priority machinery
 * running in the face of scripted stack exhaustion by something else.
 *
 * The stack quotas for each kind of code should be monotonically descending,
 * and may be specified with this function. If 0 is passed for a given kind
 * of code, it defaults to the value of the next-highest-priority kind.
 *
 * This function may only be called immediately after the runtime is initialized
 * and before any code is executed and/or interrupts requested.
 */
extern JS_PUBLIC_API void JS_SetNativeStackQuota(
    JSContext* cx, size_t systemCodeStackSize,
    size_t trustedScriptStackSize = 0, size_t untrustedScriptStackSize = 0);

/************************************************************************/

extern JS_PUBLIC_API bool JS_ValueToId(JSContext* cx, JS::HandleValue v,
                                       JS::MutableHandleId idp);

extern JS_PUBLIC_API bool JS_StringToId(JSContext* cx, JS::HandleString s,
                                        JS::MutableHandleId idp);

extern JS_PUBLIC_API bool JS_IdToValue(JSContext* cx, jsid id,
                                       JS::MutableHandle<JS::Value> vp);

namespace JS {

/**
 * Convert obj to a primitive value. On success, store the result in vp and
 * return true.
 *
 * The hint argument must be JSTYPE_STRING, JSTYPE_NUMBER, or
 * JSTYPE_UNDEFINED (no hint).
 *
 * Implements: ES6 7.1.1 ToPrimitive(input, [PreferredType]).
 */
extern JS_PUBLIC_API bool ToPrimitive(JSContext* cx, JS::HandleObject obj,
                                      JSType hint, JS::MutableHandleValue vp);

/**
 * If args.get(0) is one of the strings "string", "number", or "default", set
 * result to JSTYPE_STRING, JSTYPE_NUMBER, or JSTYPE_UNDEFINED accordingly and
 * return true. Otherwise, return false with a TypeError pending.
 *
 * This can be useful in implementing a @@toPrimitive method.
 */
extern JS_PUBLIC_API bool GetFirstArgumentAsTypeHint(JSContext* cx,
                                                     CallArgs args,
                                                     JSType* result);

} /* namespace JS */

template <typename T>
struct JSConstScalarSpec {
  const char* name;
  T val;
};

typedef JSConstScalarSpec<double> JSConstDoubleSpec;
typedef JSConstScalarSpec<int32_t> JSConstIntegerSpec;

struct JSJitInfo;

/**
 * Wrapper to relace JSNative for JSPropertySpecs and JSFunctionSpecs. This will
 * allow us to pass one JSJitInfo per function with the property/function spec,
 * without additional field overhead.
 */
struct JSNativeWrapper {
  JSNative op;
  const JSJitInfo* info;
};

/*
 * Macro static initializers which make it easy to pass no JSJitInfo as part of
 * a JSPropertySpec or JSFunctionSpec.
 */
#define JSNATIVE_WRAPPER(native) \
  {                              \
    { native, nullptr }          \
  }

/**
 * Description of a property. JS_DefineProperties and JS_InitClass take arrays
 * of these and define many properties at once. JS_PSG, JS_PSGS and JS_PS_END
 * are helper macros for defining such arrays.
 */
struct JSPropertySpec {
  struct SelfHostedWrapper {
    void* unused;
    const char* funname;
  };

  struct ValueWrapper {
    uintptr_t type;
    union {
      const char* string;
      int32_t int32;
    };
  };

  const char* name;
  uint8_t flags;
  union {
    struct {
      union {
        JSNativeWrapper native;
        SelfHostedWrapper selfHosted;
      } getter;
      union {
        JSNativeWrapper native;
        SelfHostedWrapper selfHosted;
      } setter;
    } accessors;
    ValueWrapper value;
  };

  bool isAccessor() const { return !(flags & JSPROP_INTERNAL_USE_BIT); }
  JS_PUBLIC_API bool getValue(JSContext* cx,
                              JS::MutableHandleValue value) const;

  bool isSelfHosted() const {
    MOZ_ASSERT(isAccessor());

#ifdef DEBUG
    // Verify that our accessors match our JSPROP_GETTER flag.
    if (flags & JSPROP_GETTER)
      checkAccessorsAreSelfHosted();
    else
      checkAccessorsAreNative();
#endif
    return (flags & JSPROP_GETTER);
  }

  static_assert(sizeof(SelfHostedWrapper) == sizeof(JSNativeWrapper),
                "JSPropertySpec::getter/setter must be compact");
  static_assert(offsetof(SelfHostedWrapper, funname) ==
                    offsetof(JSNativeWrapper, info),
                "JS_SELF_HOSTED* macros below require that "
                "SelfHostedWrapper::funname overlay "
                "JSNativeWrapper::info");

 private:
  void checkAccessorsAreNative() const {
    MOZ_ASSERT(accessors.getter.native.op);
    // We may not have a setter at all.  So all we can assert here, for the
    // native case is that if we have a jitinfo for the setter then we have
    // a setter op too.  This is good enough to make sure we don't have a
    // SelfHostedWrapper for the setter.
    MOZ_ASSERT_IF(accessors.setter.native.info, accessors.setter.native.op);
  }

  void checkAccessorsAreSelfHosted() const {
    MOZ_ASSERT(!accessors.getter.selfHosted.unused);
    MOZ_ASSERT(!accessors.setter.selfHosted.unused);
  }
};

namespace JS {
namespace detail {

/* NEVER DEFINED, DON'T USE.  For use by JS_CAST_NATIVE_TO only. */
inline int CheckIsNative(JSNative native);

/* NEVER DEFINED, DON'T USE.  For use by JS_CAST_STRING_TO only. */
template <size_t N>
inline int CheckIsCharacterLiteral(const char (&arr)[N]);

/* NEVER DEFINED, DON'T USE.  For use by JS_CAST_INT32_TO only. */
inline int CheckIsInt32(int32_t value);

/* NEVER DEFINED, DON'T USE.  For use by JS_PROPERTYOP_GETTER only. */
inline int CheckIsGetterOp(JSGetterOp op);

/* NEVER DEFINED, DON'T USE.  For use by JS_PROPERTYOP_SETTER only. */
inline int CheckIsSetterOp(JSSetterOp op);

}  // namespace detail
}  // namespace JS

#define JS_CAST_NATIVE_TO(v, To)                            \
  (static_cast<void>(sizeof(JS::detail::CheckIsNative(v))), \
   reinterpret_cast<To>(v))

#define JS_CAST_STRING_TO(s, To)                                      \
  (static_cast<void>(sizeof(JS::detail::CheckIsCharacterLiteral(s))), \
   reinterpret_cast<To>(s))

#define JS_CAST_INT32_TO(s, To)                            \
  (static_cast<void>(sizeof(JS::detail::CheckIsInt32(s))), \
   reinterpret_cast<To>(s))

#define JS_CHECK_ACCESSOR_FLAGS(flags)                                     \
  (static_cast<mozilla::EnableIf<                                          \
       ((flags) & ~(JSPROP_ENUMERATE | JSPROP_PERMANENT)) == 0>::Type>(0), \
   (flags))

#define JS_PROPERTYOP_GETTER(v)                               \
  (static_cast<void>(sizeof(JS::detail::CheckIsGetterOp(v))), \
   reinterpret_cast<JSNative>(v))

#define JS_PROPERTYOP_SETTER(v)                               \
  (static_cast<void>(sizeof(JS::detail::CheckIsSetterOp(v))), \
   reinterpret_cast<JSNative>(v))

#define JS_PS_ACCESSOR_SPEC(name, getter, setter, flags, extraFlags) \
  {                                                                  \
    name, uint8_t(JS_CHECK_ACCESSOR_FLAGS(flags) | extraFlags), {    \
      { getter, setter }                                             \
    }                                                                \
  }
#define JS_PS_VALUE_SPEC(name, value, flags)          \
  {                                                   \
    name, uint8_t(flags | JSPROP_INTERNAL_USE_BIT), { \
      { value, JSNATIVE_WRAPPER(nullptr) }            \
    }                                                 \
  }

#define SELFHOSTED_WRAPPER(name)                           \
  {                                                        \
    { nullptr, JS_CAST_STRING_TO(name, const JSJitInfo*) } \
  }
#define STRINGVALUE_WRAPPER(value)                   \
  {                                                  \
    {                                                \
      reinterpret_cast<JSNative>(JSVAL_TYPE_STRING), \
          JS_CAST_STRING_TO(value, const JSJitInfo*) \
    }                                                \
  }
#define INT32VALUE_WRAPPER(value)                   \
  {                                                 \
    {                                               \
      reinterpret_cast<JSNative>(JSVAL_TYPE_INT32), \
          JS_CAST_INT32_TO(value, const JSJitInfo*) \
    }                                               \
  }

/*
 * JSPropertySpec uses JSNativeWrapper.  These macros encapsulate the definition
 * of JSNative-backed JSPropertySpecs, by defining the JSNativeWrappers for
 * them.
 */
#define JS_PSG(name, getter, flags)                   \
  JS_PS_ACCESSOR_SPEC(name, JSNATIVE_WRAPPER(getter), \
                      JSNATIVE_WRAPPER(nullptr), flags, 0)
#define JS_PSGS(name, getter, setter, flags)          \
  JS_PS_ACCESSOR_SPEC(name, JSNATIVE_WRAPPER(getter), \
                      JSNATIVE_WRAPPER(setter), flags, 0)
#define JS_SYM_GET(symbol, getter, flags)                                    \
  JS_PS_ACCESSOR_SPEC(                                                       \
      reinterpret_cast<const char*>(uint32_t(::JS::SymbolCode::symbol) + 1), \
      JSNATIVE_WRAPPER(getter), JSNATIVE_WRAPPER(nullptr), flags, 0)
#define JS_SELF_HOSTED_GET(name, getterName, flags)         \
  JS_PS_ACCESSOR_SPEC(name, SELFHOSTED_WRAPPER(getterName), \
                      JSNATIVE_WRAPPER(nullptr), flags, JSPROP_GETTER)
#define JS_SELF_HOSTED_GETSET(name, getterName, setterName, flags) \
  JS_PS_ACCESSOR_SPEC(name, SELFHOSTED_WRAPPER(getterName),        \
                      SELFHOSTED_WRAPPER(setterName), flags,       \
                      JSPROP_GETTER | JSPROP_SETTER)
#define JS_SELF_HOSTED_SYM_GET(symbol, getterName, flags)                    \
  JS_PS_ACCESSOR_SPEC(                                                       \
      reinterpret_cast<const char*>(uint32_t(::JS::SymbolCode::symbol) + 1), \
      SELFHOSTED_WRAPPER(getterName), JSNATIVE_WRAPPER(nullptr), flags,      \
      JSPROP_GETTER)
#define JS_STRING_PS(name, string, flags) \
  JS_PS_VALUE_SPEC(name, STRINGVALUE_WRAPPER(string), flags)
#define JS_STRING_SYM_PS(symbol, string, flags)                              \
  JS_PS_VALUE_SPEC(                                                          \
      reinterpret_cast<const char*>(uint32_t(::JS::SymbolCode::symbol) + 1), \
      STRINGVALUE_WRAPPER(string), flags)
#define JS_INT32_PS(name, value, flags) \
  JS_PS_VALUE_SPEC(name, INT32VALUE_WRAPPER(value), flags)
#define JS_PS_END                                         \
  JS_PS_ACCESSOR_SPEC(nullptr, JSNATIVE_WRAPPER(nullptr), \
                      JSNATIVE_WRAPPER(nullptr), 0, 0)

/**
 * To define a native function, set call to a JSNativeWrapper. To define a
 * self-hosted function, set selfHostedName to the name of a function
 * compiled during JSRuntime::initSelfHosting.
 */
struct JSFunctionSpec {
  const char* name;
  JSNativeWrapper call;
  uint16_t nargs;
  uint16_t flags;
  const char* selfHostedName;
};

/*
 * Terminating sentinel initializer to put at the end of a JSFunctionSpec array
 * that's passed to JS_DefineFunctions or JS_InitClass.
 */
#define JS_FS_END JS_FN(nullptr, nullptr, 0, 0)

/*
 * Initializer macros for a JSFunctionSpec array element. JS_FNINFO allows the
 * simple adding of JSJitInfos. JS_SELF_HOSTED_FN declares a self-hosted
 * function. JS_INLINABLE_FN allows specifying an InlinableNative enum value for
 * natives inlined or specialized by the JIT. Finally JS_FNSPEC has slots for
 * all the fields.
 *
 * The _SYM variants allow defining a function with a symbol key rather than a
 * string key. For example, use JS_SYM_FN(iterator, ...) to define an
 * @@iterator method.
 */
#define JS_FN(name, call, nargs, flags) \
  JS_FNSPEC(name, call, nullptr, nargs, flags, nullptr)
#define JS_INLINABLE_FN(name, call, nargs, flags, native) \
  JS_FNSPEC(name, call, &js::jit::JitInfo_##native, nargs, flags, nullptr)
#define JS_SYM_FN(symbol, call, nargs, flags) \
  JS_SYM_FNSPEC(symbol, call, nullptr, nargs, flags, nullptr)
#define JS_FNINFO(name, call, info, nargs, flags) \
  JS_FNSPEC(name, call, info, nargs, flags, nullptr)
#define JS_SELF_HOSTED_FN(name, selfHostedName, nargs, flags) \
  JS_FNSPEC(name, nullptr, nullptr, nargs, flags, selfHostedName)
#define JS_SELF_HOSTED_SYM_FN(symbol, selfHostedName, nargs, flags) \
  JS_SYM_FNSPEC(symbol, nullptr, nullptr, nargs, flags, selfHostedName)
#define JS_SYM_FNSPEC(symbol, call, info, nargs, flags, selfHostedName)      \
  JS_FNSPEC(                                                                 \
      reinterpret_cast<const char*>(uint32_t(::JS::SymbolCode::symbol) + 1), \
      call, info, nargs, flags, selfHostedName)
#define JS_FNSPEC(name, call, info, nargs, flags, selfHostedName) \
  { name, {call, info}, nargs, flags, selfHostedName }

extern JS_PUBLIC_API JSObject* JS_InitClass(
    JSContext* cx, JS::HandleObject obj, JS::HandleObject parent_proto,
    const JSClass* clasp, JSNative constructor, unsigned nargs,
    const JSPropertySpec* ps, const JSFunctionSpec* fs,
    const JSPropertySpec* static_ps, const JSFunctionSpec* static_fs);

/**
 * Set up ctor.prototype = proto and proto.constructor = ctor with the
 * right property flags.
 */
extern JS_PUBLIC_API bool JS_LinkConstructorAndPrototype(
    JSContext* cx, JS::Handle<JSObject*> ctor, JS::Handle<JSObject*> proto);

extern JS_PUBLIC_API const JSClass* JS_GetClass(JSObject* obj);

extern JS_PUBLIC_API bool JS_InstanceOf(JSContext* cx,
                                        JS::Handle<JSObject*> obj,
                                        const JSClass* clasp,
                                        JS::CallArgs* args);

extern JS_PUBLIC_API bool JS_HasInstance(JSContext* cx,
                                         JS::Handle<JSObject*> obj,
                                         JS::Handle<JS::Value> v, bool* bp);

namespace JS {

// Implementation of
// http://www.ecma-international.org/ecma-262/6.0/#sec-ordinaryhasinstance.  If
// you're looking for the equivalent of "instanceof", you want JS_HasInstance,
// not this function.
extern JS_PUBLIC_API bool OrdinaryHasInstance(JSContext* cx,
                                              HandleObject objArg,
                                              HandleValue v, bool* bp);

}  // namespace JS

extern JS_PUBLIC_API void* JS_GetPrivate(JSObject* obj);

extern JS_PUBLIC_API void JS_SetPrivate(JSObject* obj, void* data);

extern JS_PUBLIC_API void* JS_GetInstancePrivate(JSContext* cx,
                                                 JS::Handle<JSObject*> obj,
                                                 const JSClass* clasp,
                                                 JS::CallArgs* args);

extern JS_PUBLIC_API JSObject* JS_GetConstructor(JSContext* cx,
                                                 JS::Handle<JSObject*> proto);

namespace JS {

// Specification for which zone a newly created compartment should use.
enum ZoneSpecifier {
  // Use the single runtime wide system zone. The meaning of this zone is
  // left to the embedder.
  SystemZone,

  // Use a particular existing zone.
  ExistingZone,

  // Create a new zone with its own new zone group.
  NewZoneInNewZoneGroup,

  // Create a new zone in the same zone group as the system zone.
  NewZoneInSystemZoneGroup,

  // Create a new zone in the same zone group as another existing zone.
  NewZoneInExistingZoneGroup
};

/**
 * CompartmentCreationOptions specifies options relevant to creating a new
 * compartment, that are either immutable characteristics of that compartment
 * or that are discarded after the compartment has been created.
 *
 * Access to these options on an existing compartment is read-only: if you
 * need particular selections, make them before you create the compartment.
 */
class JS_PUBLIC_API CompartmentCreationOptions {
 public:
  CompartmentCreationOptions()
      : addonId_(nullptr),
        traceGlobal_(nullptr),
        zoneSpec_(NewZoneInSystemZoneGroup),
        zonePointer_(nullptr),
        invisibleToDebugger_(false),
        mergeable_(false),
        preserveJitCode_(false),
        cloneSingletons_(false),
        sharedMemoryAndAtomics_(false),
        secureContext_(false),
        clampAndJitterTime_(true) {}

  // A null add-on ID means that the compartment is not associated with an
  // add-on.
  JSAddonId* addonIdOrNull() const { return addonId_; }
  CompartmentCreationOptions& setAddonId(JSAddonId* id) {
    addonId_ = id;
    return *this;
  }

  JSTraceOp getTrace() const { return traceGlobal_; }
  CompartmentCreationOptions& setTrace(JSTraceOp op) {
    traceGlobal_ = op;
    return *this;
  }

  void* zonePointer() const { return zonePointer_; }
  ZoneSpecifier zoneSpecifier() const { return zoneSpec_; }

  // Set the zone to use for the compartment. See ZoneSpecifier above.
  CompartmentCreationOptions& setSystemZone();
  CompartmentCreationOptions& setExistingZone(JSObject* obj);
  CompartmentCreationOptions& setNewZoneInNewZoneGroup();
  CompartmentCreationOptions& setNewZoneInSystemZoneGroup();
  CompartmentCreationOptions& setNewZoneInExistingZoneGroup(JSObject* obj);

  // Certain scopes (i.e. XBL compilation scopes) are implementation details
  // of the embedding, and references to them should never leak out to script.
  // This flag causes the this compartment to skip firing onNewGlobalObject
  // and makes addDebuggee a no-op for this global.
  bool invisibleToDebugger() const { return invisibleToDebugger_; }
  CompartmentCreationOptions& setInvisibleToDebugger(bool flag) {
    invisibleToDebugger_ = flag;
    return *this;
  }

  // Compartments used for off-thread compilation have their contents merged
  // into a target compartment when the compilation is finished. This is only
  // allowed if this flag is set. The invisibleToDebugger flag must also be
  // set for such compartments.
  bool mergeable() const { return mergeable_; }
  CompartmentCreationOptions& setMergeable(bool flag) {
    mergeable_ = flag;
    return *this;
  }

  // Determines whether this compartment should preserve JIT code on
  // non-shrinking GCs.
  bool preserveJitCode() const { return preserveJitCode_; }
  CompartmentCreationOptions& setPreserveJitCode(bool flag) {
    preserveJitCode_ = flag;
    return *this;
  }

  bool cloneSingletons() const { return cloneSingletons_; }
  CompartmentCreationOptions& setCloneSingletons(bool flag) {
    cloneSingletons_ = flag;
    return *this;
  }

  bool getSharedMemoryAndAtomicsEnabled() const;
  CompartmentCreationOptions& setSharedMemoryAndAtomicsEnabled(bool flag);

  // This flag doesn't affect JS engine behavior.  It is used by Gecko to
  // mark whether content windows and workers are "Secure Context"s. See
  // https://w3c.github.io/webappsec-secure-contexts/
  // https://bugzilla.mozilla.org/show_bug.cgi?id=1162772#c34
  bool secureContext() const { return secureContext_; }
  CompartmentCreationOptions& setSecureContext(bool flag) {
    secureContext_ = flag;
    return *this;
  }

  bool clampAndJitterTime() const { return clampAndJitterTime_; }
  CompartmentCreationOptions& setClampAndJitterTime(bool flag) {
    clampAndJitterTime_ = flag;
    return *this;
  }

 private:
  JSAddonId* addonId_;
  JSTraceOp traceGlobal_;
  ZoneSpecifier zoneSpec_;
  void* zonePointer_;  // Per zoneSpec_, either a Zone, ZoneGroup, or null.
  bool invisibleToDebugger_;
  bool mergeable_;
  bool preserveJitCode_;
  bool cloneSingletons_;
  bool sharedMemoryAndAtomics_;
  bool secureContext_;
  bool clampAndJitterTime_;
};

/**
 * CompartmentBehaviors specifies behaviors of a compartment that can be
 * changed after the compartment's been created.
 */
class JS_PUBLIC_API CompartmentBehaviors {
 public:
  class Override {
   public:
    Override() : mode_(Default) {}

    bool get(bool defaultValue) const {
      if (mode_ == Default) return defaultValue;
      return mode_ == ForceTrue;
    }

    void set(bool overrideValue) {
      mode_ = overrideValue ? ForceTrue : ForceFalse;
    }

    void reset() { mode_ = Default; }

   private:
    enum Mode { Default, ForceTrue, ForceFalse };

    Mode mode_;
  };

  CompartmentBehaviors()
      : discardSource_(false),
        disableLazyParsing_(false),
        singletonsAsTemplates_(true) {}

  // For certain globals, we know enough about the code that will run in them
  // that we can discard script source entirely.
  bool discardSource() const { return discardSource_; }
  CompartmentBehaviors& setDiscardSource(bool flag) {
    discardSource_ = flag;
    return *this;
  }

  bool disableLazyParsing() const { return disableLazyParsing_; }
  CompartmentBehaviors& setDisableLazyParsing(bool flag) {
    disableLazyParsing_ = flag;
    return *this;
  }

  bool extraWarnings(JSContext* cx) const;
  Override& extraWarningsOverride() { return extraWarningsOverride_; }

  bool getSingletonsAsTemplates() const { return singletonsAsTemplates_; }
  CompartmentBehaviors& setSingletonsAsValues() {
    singletonsAsTemplates_ = false;
    return *this;
  }

 private:
  bool discardSource_;
  bool disableLazyParsing_;
  Override extraWarningsOverride_;

  // To XDR singletons, we need to ensure that all singletons are all used as
  // templates, by making JSOP_OBJECT return a clone of the JSScript
  // singleton, instead of returning the value which is baked in the JSScript.
  bool singletonsAsTemplates_;
};

/**
 * CompartmentOptions specifies compartment characteristics: both those that
 * can't be changed on a compartment once it's been created
 * (CompartmentCreationOptions), and those that can be changed on an existing
 * compartment (CompartmentBehaviors).
 */
class JS_PUBLIC_API CompartmentOptions {
 public:
  explicit CompartmentOptions() : creationOptions_(), behaviors_() {}

  CompartmentOptions(const CompartmentCreationOptions& compartmentCreation,
                     const CompartmentBehaviors& compartmentBehaviors)
      : creationOptions_(compartmentCreation),
        behaviors_(compartmentBehaviors) {}

  // CompartmentCreationOptions specify fundamental compartment
  // characteristics that must be specified when the compartment is created,
  // that can't be changed after the compartment is created.
  CompartmentCreationOptions& creationOptions() { return creationOptions_; }
  const CompartmentCreationOptions& creationOptions() const {
    return creationOptions_;
  }

  // CompartmentBehaviors specify compartment characteristics that can be
  // changed after the compartment is created.
  CompartmentBehaviors& behaviors() { return behaviors_; }
  const CompartmentBehaviors& behaviors() const { return behaviors_; }

 private:
  CompartmentCreationOptions creationOptions_;
  CompartmentBehaviors behaviors_;
};

JS_PUBLIC_API const CompartmentCreationOptions& CompartmentCreationOptionsRef(
    JSCompartment* compartment);

JS_PUBLIC_API const CompartmentCreationOptions& CompartmentCreationOptionsRef(
    JSObject* obj);

JS_PUBLIC_API const CompartmentCreationOptions& CompartmentCreationOptionsRef(
    JSContext* cx);

JS_PUBLIC_API CompartmentBehaviors& CompartmentBehaviorsRef(
    JSCompartment* compartment);

JS_PUBLIC_API CompartmentBehaviors& CompartmentBehaviorsRef(JSObject* obj);

JS_PUBLIC_API CompartmentBehaviors& CompartmentBehaviorsRef(JSContext* cx);

/**
 * During global creation, we fire notifications to callbacks registered
 * via the Debugger API. These callbacks are arbitrary script, and can touch
 * the global in arbitrary ways. When that happens, the global should not be
 * in a half-baked state. But this creates a problem for consumers that need
 * to set slots on the global to put it in a consistent state.
 *
 * This API provides a way for consumers to set slots atomically (immediately
 * after the global is created), before any debugger hooks are fired. It's
 * unfortunately on the clunky side, but that's the way the cookie crumbles.
 *
 * If callers have no additional state on the global to set up, they may pass
 * |FireOnNewGlobalHook| to JS_NewGlobalObject, which causes that function to
 * fire the hook as its final act before returning. Otherwise, callers should
 * pass |DontFireOnNewGlobalHook|, which means that they are responsible for
 * invoking JS_FireOnNewGlobalObject upon successfully creating the global. If
 * an error occurs and the operation aborts, callers should skip firing the
 * hook. But otherwise, callers must take care to fire the hook exactly once
 * before compiling any script in the global's scope (we have assertions in
 * place to enforce this). This lets us be sure that debugger clients never miss
 * breakpoints.
 */
enum OnNewGlobalHookOption { FireOnNewGlobalHook, DontFireOnNewGlobalHook };

} /* namespace JS */

extern JS_PUBLIC_API JSObject* JS_NewGlobalObject(
    JSContext* cx, const JSClass* clasp, JSPrincipals* principals,
    JS::OnNewGlobalHookOption hookOption,
    const JS::CompartmentOptions& options);
/**
 * Spidermonkey does not have a good way of keeping track of what compartments
 * should be marked on their own. We can mark the roots unconditionally, but
 * marking GC things only relevant in live compartments is hard. To mitigate
 * this, we create a static trace hook, installed on each global object, from
 * which we can be sure the compartment is relevant, and mark it.
 *
 * It is still possible to specify custom trace hooks for global object classes.
 * They can be provided via the CompartmentOptions passed to JS_NewGlobalObject.
 */
extern JS_PUBLIC_API void JS_GlobalObjectTraceHook(JSTracer* trc,
                                                   JSObject* global);

extern JS_PUBLIC_API void JS_FireOnNewGlobalObject(JSContext* cx,
                                                   JS::HandleObject global);

extern JS_PUBLIC_API JSObject* JS_NewObject(JSContext* cx,
                                            const JSClass* clasp);

extern JS_PUBLIC_API bool JS_IsNative(JSObject* obj);

/**
 * Unlike JS_NewObject, JS_NewObjectWithGivenProto does not compute a default
 * proto. If proto is nullptr, the JS object will have `null` as [[Prototype]].
 */
extern JS_PUBLIC_API JSObject* JS_NewObjectWithGivenProto(
    JSContext* cx, const JSClass* clasp, JS::Handle<JSObject*> proto);

/** Creates a new plain object, like `new Object()`, with Object.prototype as
 * [[Prototype]]. */
extern JS_PUBLIC_API JSObject* JS_NewPlainObject(JSContext* cx);

/**
 * Freeze obj, and all objects it refers to, recursively. This will not recurse
 * through non-extensible objects, on the assumption that those are already
 * deep-frozen.
 */
extern JS_PUBLIC_API bool JS_DeepFreezeObject(JSContext* cx,
                                              JS::Handle<JSObject*> obj);

/**
 * Freezes an object; see ES5's Object.freeze(obj) method.
 */
extern JS_PUBLIC_API bool JS_FreezeObject(JSContext* cx,
                                          JS::Handle<JSObject*> obj);

/*** Property descriptors ***************************************************/

namespace JS {

struct JS_PUBLIC_API PropertyDescriptor {
  JSObject* obj;
  unsigned attrs;
  JSGetterOp getter;
  JSSetterOp setter;
  JS::Value value;

  PropertyDescriptor()
      : obj(nullptr),
        attrs(0),
        getter(nullptr),
        setter(nullptr),
        value(JS::UndefinedValue()) {}

  static void trace(PropertyDescriptor* self, JSTracer* trc) {
    self->trace(trc);
  }
  void trace(JSTracer* trc);
};

}  // namespace JS

namespace js {

template <typename Wrapper>
class WrappedPtrOperations<JS::PropertyDescriptor, Wrapper> {
  const JS::PropertyDescriptor& desc() const {
    return static_cast<const Wrapper*>(this)->get();
  }

  bool has(unsigned bit) const {
    MOZ_ASSERT(bit != 0);
    MOZ_ASSERT((bit & (bit - 1)) == 0);  // only a single bit
    return (desc().attrs & bit) != 0;
  }

  bool hasAny(unsigned bits) const { return (desc().attrs & bits) != 0; }

  bool hasAll(unsigned bits) const { return (desc().attrs & bits) == bits; }

  // Non-API attributes bit used internally for arguments objects.
  enum { SHADOWABLE = JSPROP_INTERNAL_USE_BIT };

 public:
  // Descriptors with JSGetterOp/JSSetterOp are considered data
  // descriptors. It's complicated.
  bool isAccessorDescriptor() const {
    return hasAny(JSPROP_GETTER | JSPROP_SETTER);
  }
  bool isGenericDescriptor() const {
    return (desc().attrs & (JSPROP_GETTER | JSPROP_SETTER |
                            JSPROP_IGNORE_READONLY | JSPROP_IGNORE_VALUE)) ==
           (JSPROP_IGNORE_READONLY | JSPROP_IGNORE_VALUE);
  }
  bool isDataDescriptor() const {
    return !isAccessorDescriptor() && !isGenericDescriptor();
  }

  bool hasConfigurable() const { return !has(JSPROP_IGNORE_PERMANENT); }
  bool configurable() const {
    MOZ_ASSERT(hasConfigurable());
    return !has(JSPROP_PERMANENT);
  }

  bool hasEnumerable() const { return !has(JSPROP_IGNORE_ENUMERATE); }
  bool enumerable() const {
    MOZ_ASSERT(hasEnumerable());
    return has(JSPROP_ENUMERATE);
  }

  bool hasValue() const {
    return !isAccessorDescriptor() && !has(JSPROP_IGNORE_VALUE);
  }
  JS::HandleValue value() const {
    return JS::HandleValue::fromMarkedLocation(&desc().value);
  }

  bool hasWritable() const {
    return !isAccessorDescriptor() && !has(JSPROP_IGNORE_READONLY);
  }
  bool writable() const {
    MOZ_ASSERT(hasWritable());
    return !has(JSPROP_READONLY);
  }

  bool hasGetterObject() const { return has(JSPROP_GETTER); }
  JS::HandleObject getterObject() const {
    MOZ_ASSERT(hasGetterObject());
    return JS::HandleObject::fromMarkedLocation(
        reinterpret_cast<JSObject* const*>(&desc().getter));
  }
  bool hasSetterObject() const { return has(JSPROP_SETTER); }
  JS::HandleObject setterObject() const {
    MOZ_ASSERT(hasSetterObject());
    return JS::HandleObject::fromMarkedLocation(
        reinterpret_cast<JSObject* const*>(&desc().setter));
  }

  bool hasGetterOrSetter() const { return desc().getter || desc().setter; }

  JS::HandleObject object() const {
    return JS::HandleObject::fromMarkedLocation(&desc().obj);
  }
  unsigned attributes() const { return desc().attrs; }
  JSGetterOp getter() const { return desc().getter; }
  JSSetterOp setter() const { return desc().setter; }

  void assertValid() const {
#ifdef DEBUG
    MOZ_ASSERT((attributes() &
                ~(JSPROP_ENUMERATE | JSPROP_IGNORE_ENUMERATE |
                  JSPROP_PERMANENT | JSPROP_IGNORE_PERMANENT | JSPROP_READONLY |
                  JSPROP_IGNORE_READONLY | JSPROP_IGNORE_VALUE | JSPROP_GETTER |
                  JSPROP_SETTER | JSPROP_REDEFINE_NONCONFIGURABLE |
                  JSPROP_RESOLVING | SHADOWABLE)) == 0);
    MOZ_ASSERT(!hasAll(JSPROP_IGNORE_ENUMERATE | JSPROP_ENUMERATE));
    MOZ_ASSERT(!hasAll(JSPROP_IGNORE_PERMANENT | JSPROP_PERMANENT));
    if (isAccessorDescriptor()) {
      MOZ_ASSERT(!has(JSPROP_READONLY));
      MOZ_ASSERT(!has(JSPROP_IGNORE_READONLY));
      MOZ_ASSERT(!has(JSPROP_IGNORE_VALUE));
      MOZ_ASSERT(!has(SHADOWABLE));
      MOZ_ASSERT(value().isUndefined());
      MOZ_ASSERT_IF(!has(JSPROP_GETTER), !getter());
      MOZ_ASSERT_IF(!has(JSPROP_SETTER), !setter());
    } else {
      MOZ_ASSERT(!hasAll(JSPROP_IGNORE_READONLY | JSPROP_READONLY));
      MOZ_ASSERT_IF(has(JSPROP_IGNORE_VALUE), value().isUndefined());
    }

    MOZ_ASSERT_IF(has(JSPROP_RESOLVING), !has(JSPROP_IGNORE_ENUMERATE));
    MOZ_ASSERT_IF(has(JSPROP_RESOLVING), !has(JSPROP_IGNORE_PERMANENT));
    MOZ_ASSERT_IF(has(JSPROP_RESOLVING), !has(JSPROP_IGNORE_READONLY));
    MOZ_ASSERT_IF(has(JSPROP_RESOLVING), !has(JSPROP_IGNORE_VALUE));
    MOZ_ASSERT_IF(has(JSPROP_RESOLVING), !has(JSPROP_REDEFINE_NONCONFIGURABLE));
#endif
  }

  void assertComplete() const {
#ifdef DEBUG
    assertValid();
    MOZ_ASSERT(
        (attributes() &
         ~(JSPROP_ENUMERATE | JSPROP_PERMANENT | JSPROP_READONLY |
           JSPROP_GETTER | JSPROP_SETTER | JSPROP_REDEFINE_NONCONFIGURABLE |
           JSPROP_RESOLVING | SHADOWABLE)) == 0);
    MOZ_ASSERT_IF(isAccessorDescriptor(),
                  has(JSPROP_GETTER) && has(JSPROP_SETTER));
#endif
  }

  void assertCompleteIfFound() const {
#ifdef DEBUG
    if (object()) assertComplete();
#endif
  }
};

template <typename Wrapper>
class MutableWrappedPtrOperations<JS::PropertyDescriptor, Wrapper>
    : public js::WrappedPtrOperations<JS::PropertyDescriptor, Wrapper> {
  JS::PropertyDescriptor& desc() { return static_cast<Wrapper*>(this)->get(); }

 public:
  void clear() {
    object().set(nullptr);
    setAttributes(0);
    setGetter(nullptr);
    setSetter(nullptr);
    value().setUndefined();
  }

  void initFields(JS::HandleObject obj, JS::HandleValue v, unsigned attrs,
                  JSGetterOp getterOp, JSSetterOp setterOp) {
    object().set(obj);
    value().set(v);
    setAttributes(attrs);
    setGetter(getterOp);
    setSetter(setterOp);
  }

  void assign(JS::PropertyDescriptor& other) {
    object().set(other.obj);
    setAttributes(other.attrs);
    setGetter(other.getter);
    setSetter(other.setter);
    value().set(other.value);
  }

  void setDataDescriptor(JS::HandleValue v, unsigned attrs) {
    MOZ_ASSERT((attrs & ~(JSPROP_ENUMERATE | JSPROP_PERMANENT |
                          JSPROP_READONLY | JSPROP_IGNORE_ENUMERATE |
                          JSPROP_IGNORE_PERMANENT | JSPROP_IGNORE_READONLY)) ==
               0);
    object().set(nullptr);
    setAttributes(attrs);
    setGetter(nullptr);
    setSetter(nullptr);
    value().set(v);
  }

  JS::MutableHandleObject object() {
    return JS::MutableHandleObject::fromMarkedLocation(&desc().obj);
  }
  unsigned& attributesRef() { return desc().attrs; }
  JSGetterOp& getter() { return desc().getter; }
  JSSetterOp& setter() { return desc().setter; }
  JS::MutableHandleValue value() {
    return JS::MutableHandleValue::fromMarkedLocation(&desc().value);
  }
  void setValue(JS::HandleValue v) {
    MOZ_ASSERT(!(desc().attrs & (JSPROP_GETTER | JSPROP_SETTER)));
    attributesRef() &= ~JSPROP_IGNORE_VALUE;
    value().set(v);
  }

  void setConfigurable(bool configurable) {
    setAttributes(
        (desc().attrs & ~(JSPROP_IGNORE_PERMANENT | JSPROP_PERMANENT)) |
        (configurable ? 0 : JSPROP_PERMANENT));
  }
  void setEnumerable(bool enumerable) {
    setAttributes(
        (desc().attrs & ~(JSPROP_IGNORE_ENUMERATE | JSPROP_ENUMERATE)) |
        (enumerable ? JSPROP_ENUMERATE : 0));
  }
  void setWritable(bool writable) {
    MOZ_ASSERT(!(desc().attrs & (JSPROP_GETTER | JSPROP_SETTER)));
    setAttributes((desc().attrs & ~(JSPROP_IGNORE_READONLY | JSPROP_READONLY)) |
                  (writable ? 0 : JSPROP_READONLY));
  }
  void setAttributes(unsigned attrs) { desc().attrs = attrs; }

  void setGetter(JSGetterOp op) { desc().getter = op; }
  void setSetter(JSSetterOp op) { desc().setter = op; }
  void setGetterObject(JSObject* obj) {
    desc().getter = reinterpret_cast<JSGetterOp>(obj);
    desc().attrs &=
        ~(JSPROP_IGNORE_VALUE | JSPROP_IGNORE_READONLY | JSPROP_READONLY);
    desc().attrs |= JSPROP_GETTER;
  }
  void setSetterObject(JSObject* obj) {
    desc().setter = reinterpret_cast<JSSetterOp>(obj);
    desc().attrs &=
        ~(JSPROP_IGNORE_VALUE | JSPROP_IGNORE_READONLY | JSPROP_READONLY);
    desc().attrs |= JSPROP_SETTER;
  }

  JS::MutableHandleObject getterObject() {
    MOZ_ASSERT(this->hasGetterObject());
    return JS::MutableHandleObject::fromMarkedLocation(
        reinterpret_cast<JSObject**>(&desc().getter));
  }
  JS::MutableHandleObject setterObject() {
    MOZ_ASSERT(this->hasSetterObject());
    return JS::MutableHandleObject::fromMarkedLocation(
        reinterpret_cast<JSObject**>(&desc().setter));
  }
};

}  // namespace js

namespace JS {

extern JS_PUBLIC_API bool ObjectToCompletePropertyDescriptor(
    JSContext* cx, JS::HandleObject obj, JS::HandleValue descriptor,
    JS::MutableHandle<PropertyDescriptor> desc);

/*
 * ES6 draft rev 32 (2015 Feb 2) 6.2.4.4 FromPropertyDescriptor(Desc).
 *
 * If desc.object() is null, then vp is set to undefined.
 */
extern JS_PUBLIC_API bool FromPropertyDescriptor(
    JSContext* cx, JS::Handle<JS::PropertyDescriptor> desc,
    JS::MutableHandleValue vp);

}  // namespace JS

/*** Standard internal methods **********************************************
 *
 * The functions below are the fundamental operations on objects.
 *
 * ES6 specifies 14 internal methods that define how objects behave.  The
 * standard is actually quite good on this topic, though you may have to read
 * it a few times. See ES6 sections 6.1.7.2 and 6.1.7.3.
 *
 * When 'obj' is an ordinary object, these functions have boring standard
 * behavior as specified by ES6 section 9.1; see the section about internal
 * methods in js/src/vm/NativeObject.h.
 *
 * Proxies override the behavior of internal methods. So when 'obj' is a proxy,
 * any one of the functions below could do just about anything. See
 * js/public/Proxy.h.
 */

/**
 * Get the prototype of obj, storing it in result.
 *
 * Implements: ES6 [[GetPrototypeOf]] internal method.
 */
extern JS_PUBLIC_API bool JS_GetPrototype(JSContext* cx, JS::HandleObject obj,
                                          JS::MutableHandleObject result);

/**
 * If |obj| (underneath any functionally-transparent wrapper proxies) has as
 * its [[GetPrototypeOf]] trap the ordinary [[GetPrototypeOf]] behavior defined
 * for ordinary objects, set |*isOrdinary = true| and store |obj|'s prototype
 * in |result|.  Otherwise set |*isOrdinary = false|.  In case of error, both
 * outparams have unspecified value.
 */
extern JS_PUBLIC_API bool JS_GetPrototypeIfOrdinary(
    JSContext* cx, JS::HandleObject obj, bool* isOrdinary,
    JS::MutableHandleObject result);

/**
 * Change the prototype of obj.
 *
 * Implements: ES6 [[SetPrototypeOf]] internal method.
 *
 * In cases where ES6 [[SetPrototypeOf]] returns false without an exception,
 * JS_SetPrototype throws a TypeError and returns false.
 *
 * Performance warning: JS_SetPrototype is very bad for performance. It may
 * cause compiled jit-code to be invalidated. It also causes not only obj but
 * all other objects in the same "group" as obj to be permanently deoptimized.
 * It's better to create the object with the right prototype from the start.
 */
extern JS_PUBLIC_API bool JS_SetPrototype(JSContext* cx, JS::HandleObject obj,
                                          JS::HandleObject proto);

/**
 * Determine whether obj is extensible. Extensible objects can have new
 * properties defined on them. Inextensible objects can't, and their
 * [[Prototype]] slot is fixed as well.
 *
 * Implements: ES6 [[IsExtensible]] internal method.
 */
extern JS_PUBLIC_API bool JS_IsExtensible(JSContext* cx, JS::HandleObject obj,
                                          bool* extensible);

/**
 * Attempt to make |obj| non-extensible.
 *
 * Not all failures are treated as errors. See the comment on
 * JS::ObjectOpResult in js/public/Class.h.
 *
 * Implements: ES6 [[PreventExtensions]] internal method.
 */
extern JS_PUBLIC_API bool JS_PreventExtensions(JSContext* cx,
                                               JS::HandleObject obj,
                                               JS::ObjectOpResult& result);

/**
 * Attempt to make the [[Prototype]] of |obj| immutable, such that any attempt
 * to modify it will fail.  If an error occurs during the attempt, return false
 * (with a pending exception set, depending upon the nature of the error).  If
 * no error occurs, return true with |*succeeded| set to indicate whether the
 * attempt successfully made the [[Prototype]] immutable.
 *
 * This is a nonstandard internal method.
 */
extern JS_PUBLIC_API bool JS_SetImmutablePrototype(JSContext* cx,
                                                   JS::HandleObject obj,
                                                   bool* succeeded);

/**
 * Get a description of one of obj's own properties. If no such property exists
 * on obj, return true with desc.object() set to null.
 *
 * Implements: ES6 [[GetOwnProperty]] internal method.
 */
extern JS_PUBLIC_API bool JS_GetOwnPropertyDescriptorById(
    JSContext* cx, JS::HandleObject obj, JS::HandleId id,
    JS::MutableHandle<JS::PropertyDescriptor> desc);

extern JS_PUBLIC_API bool JS_GetOwnPropertyDescriptor(
    JSContext* cx, JS::HandleObject obj, const char* name,
    JS::MutableHandle<JS::PropertyDescriptor> desc);

extern JS_PUBLIC_API bool JS_GetOwnUCPropertyDescriptor(
    JSContext* cx, JS::HandleObject obj, const char16_t* name, size_t namelen,
    JS::MutableHandle<JS::PropertyDescriptor> desc);

/**
 * Like JS_GetOwnPropertyDescriptorById, but also searches the prototype chain
 * if no own property is found directly on obj. The object on which the
 * property is found is returned in desc.object(). If the property is not found
 * on the prototype chain, this returns true with desc.object() set to null.
 */
extern JS_PUBLIC_API bool JS_GetPropertyDescriptorById(
    JSContext* cx, JS::HandleObject obj, JS::HandleId id,
    JS::MutableHandle<JS::PropertyDescriptor> desc);

extern JS_PUBLIC_API bool JS_GetPropertyDescriptor(
    JSContext* cx, JS::HandleObject obj, const char* name,
    JS::MutableHandle<JS::PropertyDescriptor> desc);

extern JS_PUBLIC_API bool JS_GetUCPropertyDescriptor(
    JSContext* cx, JS::HandleObject obj, const char16_t* name, size_t namelen,
    JS::MutableHandle<JS::PropertyDescriptor> desc);

/**
 * Define a property on obj.
 *
 * This function uses JS::ObjectOpResult to indicate conditions that ES6
 * specifies as non-error failures. This is inconvenient at best, so use this
 * function only if you are implementing a proxy handler's defineProperty()
 * method. For all other purposes, use one of the many DefineProperty functions
 * below that throw an exception in all failure cases.
 *
 * Implements: ES6 [[DefineOwnProperty]] internal method.
 */
extern JS_PUBLIC_API bool JS_DefinePropertyById(
    JSContext* cx, JS::HandleObject obj, JS::HandleId id,
    JS::Handle<JS::PropertyDescriptor> desc, JS::ObjectOpResult& result);

/**
 * Define a property on obj, throwing a TypeError if the attempt fails.
 * This is the C++ equivalent of `Object.defineProperty(obj, id, desc)`.
 */
extern JS_PUBLIC_API bool JS_DefinePropertyById(
    JSContext* cx, JS::HandleObject obj, JS::HandleId id,
    JS::Handle<JS::PropertyDescriptor> desc);

extern JS_PUBLIC_API bool JS_DefinePropertyById(JSContext* cx,
                                                JS::HandleObject obj,
                                                JS::HandleId id,
                                                JS::HandleValue value,
                                                unsigned attrs);

extern JS_PUBLIC_API bool JS_DefinePropertyById(
    JSContext* cx, JS::HandleObject obj, JS::HandleId id, JSNative getter,
    JSNative setter, unsigned attrs);

extern JS_PUBLIC_API bool JS_DefinePropertyById(JSContext* cx,
                                                JS::HandleObject obj,
                                                JS::HandleId id,
                                                JS::HandleObject value,
                                                unsigned attrs);

extern JS_PUBLIC_API bool JS_DefinePropertyById(JSContext* cx,
                                                JS::HandleObject obj,
                                                JS::HandleId id,
                                                JS::HandleString value,
                                                unsigned attrs);

extern JS_PUBLIC_API bool JS_DefinePropertyById(JSContext* cx,
                                                JS::HandleObject obj,
                                                JS::HandleId id, int32_t value,
                                                unsigned attrs);

extern JS_PUBLIC_API bool JS_DefinePropertyById(JSContext* cx,
                                                JS::HandleObject obj,
                                                JS::HandleId id, uint32_t value,
                                                unsigned attrs);

extern JS_PUBLIC_API bool JS_DefinePropertyById(JSContext* cx,
                                                JS::HandleObject obj,
                                                JS::HandleId id, double value,
                                                unsigned attrs);

extern JS_PUBLIC_API bool JS_DefineProperty(JSContext* cx, JS::HandleObject obj,
                                            const char* name,
                                            JS::HandleValue value,
                                            unsigned attrs);

extern JS_PUBLIC_API bool JS_DefineProperty(JSContext* cx, JS::HandleObject obj,
                                            const char* name, JSNative getter,
                                            JSNative setter, unsigned attrs);

extern JS_PUBLIC_API bool JS_DefineProperty(JSContext* cx, JS::HandleObject obj,
                                            const char* name,
                                            JS::HandleObject value,
                                            unsigned attrs);

extern JS_PUBLIC_API bool JS_DefineProperty(JSContext* cx, JS::HandleObject obj,
                                            const char* name,
                                            JS::HandleString value,
                                            unsigned attrs);

extern JS_PUBLIC_API bool JS_DefineProperty(JSContext* cx, JS::HandleObject obj,
                                            const char* name, int32_t value,
                                            unsigned attrs);

extern JS_PUBLIC_API bool JS_DefineProperty(JSContext* cx, JS::HandleObject obj,
                                            const char* name, uint32_t value,
                                            unsigned attrs);

extern JS_PUBLIC_API bool JS_DefineProperty(JSContext* cx, JS::HandleObject obj,
                                            const char* name, double value,
                                            unsigned attrs);

extern JS_PUBLIC_API bool JS_DefineUCProperty(
    JSContext* cx, JS::HandleObject obj, const char16_t* name, size_t namelen,
    JS::Handle<JS::PropertyDescriptor> desc, JS::ObjectOpResult& result);

extern JS_PUBLIC_API bool JS_DefineUCProperty(
    JSContext* cx, JS::HandleObject obj, const char16_t* name, size_t namelen,
    JS::Handle<JS::PropertyDescriptor> desc);

extern JS_PUBLIC_API bool JS_DefineUCProperty(
    JSContext* cx, JS::HandleObject obj, const char16_t* name, size_t namelen,
    JS::HandleValue value, unsigned attrs);

extern JS_PUBLIC_API bool JS_DefineUCProperty(JSContext* cx,
                                              JS::HandleObject obj,
                                              const char16_t* name,
                                              size_t namelen, JSNative getter,
                                              JSNative setter, unsigned attrs);

extern JS_PUBLIC_API bool JS_DefineUCProperty(
    JSContext* cx, JS::HandleObject obj, const char16_t* name, size_t namelen,
    JS::HandleObject value, unsigned attrs);

extern JS_PUBLIC_API bool JS_DefineUCProperty(
    JSContext* cx, JS::HandleObject obj, const char16_t* name, size_t namelen,
    JS::HandleString value, unsigned attrs);

extern JS_PUBLIC_API bool JS_DefineUCProperty(JSContext* cx,
                                              JS::HandleObject obj,
                                              const char16_t* name,
                                              size_t namelen, int32_t value,
                                              unsigned attrs);

extern JS_PUBLIC_API bool JS_DefineUCProperty(JSContext* cx,
                                              JS::HandleObject obj,
                                              const char16_t* name,
                                              size_t namelen, uint32_t value,
                                              unsigned attrs);

extern JS_PUBLIC_API bool JS_DefineUCProperty(JSContext* cx,
                                              JS::HandleObject obj,
                                              const char16_t* name,
                                              size_t namelen, double value,
                                              unsigned attrs);

extern JS_PUBLIC_API bool JS_DefineElement(JSContext* cx, JS::HandleObject obj,
                                           uint32_t index,
                                           JS::HandleValue value,
                                           unsigned attrs);

extern JS_PUBLIC_API bool JS_DefineElement(JSContext* cx, JS::HandleObject obj,
                                           uint32_t index, JSNative getter,
                                           JSNative setter, unsigned attrs);

extern JS_PUBLIC_API bool JS_DefineElement(JSContext* cx, JS::HandleObject obj,
                                           uint32_t index,
                                           JS::HandleObject value,
                                           unsigned attrs);

extern JS_PUBLIC_API bool JS_DefineElement(JSContext* cx, JS::HandleObject obj,
                                           uint32_t index,
                                           JS::HandleString value,
                                           unsigned attrs);

extern JS_PUBLIC_API bool JS_DefineElement(JSContext* cx, JS::HandleObject obj,
                                           uint32_t index, int32_t value,
                                           unsigned attrs);

extern JS_PUBLIC_API bool JS_DefineElement(JSContext* cx, JS::HandleObject obj,
                                           uint32_t index, uint32_t value,
                                           unsigned attrs);

extern JS_PUBLIC_API bool JS_DefineElement(JSContext* cx, JS::HandleObject obj,
                                           uint32_t index, double value,
                                           unsigned attrs);

/**
 * Compute the expression `id in obj`.
 *
 * If obj has an own or inherited property obj[id], set *foundp = true and
 * return true. If not, set *foundp = false and return true. On error, return
 * false with an exception pending.
 *
 * Implements: ES6 [[Has]] internal method.
 */
extern JS_PUBLIC_API bool JS_HasPropertyById(JSContext* cx,
                                             JS::HandleObject obj,
                                             JS::HandleId id, bool* foundp);

extern JS_PUBLIC_API bool JS_HasProperty(JSContext* cx, JS::HandleObject obj,
                                         const char* name, bool* foundp);

extern JS_PUBLIC_API bool JS_HasUCProperty(JSContext* cx, JS::HandleObject obj,
                                           const char16_t* name, size_t namelen,
                                           bool* vp);

extern JS_PUBLIC_API bool JS_HasElement(JSContext* cx, JS::HandleObject obj,
                                        uint32_t index, bool* foundp);

/**
 * Determine whether obj has an own property with the key `id`.
 *
 * Implements: ES6 7.3.11 HasOwnProperty(O, P).
 */
extern JS_PUBLIC_API bool JS_HasOwnPropertyById(JSContext* cx,
                                                JS::HandleObject obj,
                                                JS::HandleId id, bool* foundp);

extern JS_PUBLIC_API bool JS_HasOwnProperty(JSContext* cx, JS::HandleObject obj,
                                            const char* name, bool* foundp);

/**
 * Get the value of the property `obj[id]`, or undefined if no such property
 * exists. This is the C++ equivalent of `vp = Reflect.get(obj, id, receiver)`.
 *
 * Most callers don't need the `receiver` argument. Consider using
 * JS_GetProperty instead. (But if you're implementing a proxy handler's set()
 * method, it's often correct to call this function and pass the receiver
 * through.)
 *
 * Implements: ES6 [[Get]] internal method.
 */
extern JS_PUBLIC_API bool JS_ForwardGetPropertyTo(JSContext* cx,
                                                  JS::HandleObject obj,
                                                  JS::HandleId id,
                                                  JS::HandleValue receiver,
                                                  JS::MutableHandleValue vp);

extern JS_PUBLIC_API bool JS_ForwardGetElementTo(JSContext* cx,
                                                 JS::HandleObject obj,
                                                 uint32_t index,
                                                 JS::HandleObject receiver,
                                                 JS::MutableHandleValue vp);

/**
 * Get the value of the property `obj[id]`, or undefined if no such property
 * exists. The result is stored in vp.
 *
 * Implements: ES6 7.3.1 Get(O, P).
 */
extern JS_PUBLIC_API bool JS_GetPropertyById(JSContext* cx,
                                             JS::HandleObject obj,
                                             JS::HandleId id,
                                             JS::MutableHandleValue vp);

extern JS_PUBLIC_API bool JS_GetProperty(JSContext* cx, JS::HandleObject obj,
                                         const char* name,
                                         JS::MutableHandleValue vp);

extern JS_PUBLIC_API bool JS_GetUCProperty(JSContext* cx, JS::HandleObject obj,
                                           const char16_t* name, size_t namelen,
                                           JS::MutableHandleValue vp);

extern JS_PUBLIC_API bool JS_GetElement(JSContext* cx, JS::HandleObject obj,
                                        uint32_t index,
                                        JS::MutableHandleValue vp);

/**
 * Perform the same property assignment as `Reflect.set(obj, id, v, receiver)`.
 *
 * This function has a `receiver` argument that most callers don't need.
 * Consider using JS_SetProperty instead.
 *
 * Implements: ES6 [[Set]] internal method.
 */
extern JS_PUBLIC_API bool JS_ForwardSetPropertyTo(
    JSContext* cx, JS::HandleObject obj, JS::HandleId id, JS::HandleValue v,
    JS::HandleValue receiver, JS::ObjectOpResult& result);

/**
 * Perform the assignment `obj[id] = v`.
 *
 * This function performs non-strict assignment, so if the property is
 * read-only, nothing happens and no error is thrown.
 */
extern JS_PUBLIC_API bool JS_SetPropertyById(JSContext* cx,
                                             JS::HandleObject obj,
                                             JS::HandleId id,
                                             JS::HandleValue v);

extern JS_PUBLIC_API bool JS_SetProperty(JSContext* cx, JS::HandleObject obj,
                                         const char* name, JS::HandleValue v);

extern JS_PUBLIC_API bool JS_SetUCProperty(JSContext* cx, JS::HandleObject obj,
                                           const char16_t* name, size_t namelen,
                                           JS::HandleValue v);

extern JS_PUBLIC_API bool JS_SetElement(JSContext* cx, JS::HandleObject obj,
                                        uint32_t index, JS::HandleValue v);

extern JS_PUBLIC_API bool JS_SetElement(JSContext* cx, JS::HandleObject obj,
                                        uint32_t index, JS::HandleObject v);

extern JS_PUBLIC_API bool JS_SetElement(JSContext* cx, JS::HandleObject obj,
                                        uint32_t index, JS::HandleString v);

extern JS_PUBLIC_API bool JS_SetElement(JSContext* cx, JS::HandleObject obj,
                                        uint32_t index, int32_t v);

extern JS_PUBLIC_API bool JS_SetElement(JSContext* cx, JS::HandleObject obj,
                                        uint32_t index, uint32_t v);

extern JS_PUBLIC_API bool JS_SetElement(JSContext* cx, JS::HandleObject obj,
                                        uint32_t index, double v);

/**
 * Delete a property. This is the C++ equivalent of
 * `result = Reflect.deleteProperty(obj, id)`.
 *
 * This function has a `result` out parameter that most callers don't need.
 * Unless you can pass through an ObjectOpResult provided by your caller, it's
 * probably best to use the JS_DeletePropertyById signature with just 3
 * arguments.
 *
 * Implements: ES6 [[Delete]] internal method.
 */
extern JS_PUBLIC_API bool JS_DeletePropertyById(JSContext* cx,
                                                JS::HandleObject obj,
                                                JS::HandleId id,
                                                JS::ObjectOpResult& result);

extern JS_PUBLIC_API bool JS_DeleteProperty(JSContext* cx, JS::HandleObject obj,
                                            const char* name,
                                            JS::ObjectOpResult& result);

extern JS_PUBLIC_API bool JS_DeleteUCProperty(JSContext* cx,
                                              JS::HandleObject obj,
                                              const char16_t* name,
                                              size_t namelen,
                                              JS::ObjectOpResult& result);

extern JS_PUBLIC_API bool JS_DeleteElement(JSContext* cx, JS::HandleObject obj,
                                           uint32_t index,
                                           JS::ObjectOpResult& result);

/**
 * Delete a property, ignoring strict failures. This is the C++ equivalent of
 * the JS `delete obj[id]` in non-strict mode code.
 */
extern JS_PUBLIC_API bool JS_DeletePropertyById(JSContext* cx,
                                                JS::HandleObject obj, jsid id);

extern JS_PUBLIC_API bool JS_DeleteProperty(JSContext* cx, JS::HandleObject obj,
                                            const char* name);

extern JS_PUBLIC_API bool JS_DeleteElement(JSContext* cx, JS::HandleObject obj,
                                           uint32_t index);

/**
 * Get an array of the non-symbol enumerable properties of obj.
 * This function is roughly equivalent to:
 *
 *     var result = [];
 *     for (key in obj)
 *         result.push(key);
 *     return result;
 *
 * This is the closest thing we currently have to the ES6 [[Enumerate]]
 * internal method.
 *
 * The array of ids returned by JS_Enumerate must be rooted to protect its
 * contents from garbage collection. Use JS::Rooted<JS::IdVector>.
 */
extern JS_PUBLIC_API bool JS_Enumerate(JSContext* cx, JS::HandleObject obj,
                                       JS::MutableHandle<JS::IdVector> props);

/*
 * API for determining callability and constructability. [[Call]] and
 * [[Construct]] are internal methods that aren't present on all objects, so it
 * is useful to ask if they are there or not. The standard itself asks these
 * questions routinely.
 */
namespace JS {

/**
 * Return true if the given object is callable. In ES6 terms, an object is
 * callable if it has a [[Call]] internal method.
 *
 * Implements: ES6 7.2.3 IsCallable(argument).
 *
 * Functions are callable. A scripted proxy or wrapper is callable if its
 * target is callable. Most other objects aren't callable.
 */
extern JS_PUBLIC_API bool IsCallable(JSObject* obj);

/**
 * Return true if the given object is a constructor. In ES6 terms, an object is
 * a constructor if it has a [[Construct]] internal method. The expression
 * `new obj()` throws a TypeError if obj is not a constructor.
 *
 * Implements: ES6 7.2.4 IsConstructor(argument).
 *
 * JS functions and classes are constructors. Arrow functions and most builtin
 * functions are not. A scripted proxy or wrapper is a constructor if its
 * target is a constructor.
 */
extern JS_PUBLIC_API bool IsConstructor(JSObject* obj);

} /* namespace JS */

/**
 * Call a function, passing a this-value and arguments. This is the C++
 * equivalent of `rval = Reflect.apply(fun, obj, args)`.
 *
 * Implements: ES6 7.3.12 Call(F, V, [argumentsList]).
 * Use this function to invoke the [[Call]] internal method.
 */
extern JS_PUBLIC_API bool JS_CallFunctionValue(JSContext* cx,
                                               JS::HandleObject obj,
                                               JS::HandleValue fval,
                                               const JS::HandleValueArray& args,
                                               JS::MutableHandleValue rval);

extern JS_PUBLIC_API bool JS_CallFunction(JSContext* cx, JS::HandleObject obj,
                                          JS::HandleFunction fun,
                                          const JS::HandleValueArray& args,
                                          JS::MutableHandleValue rval);

/**
 * Perform the method call `rval = obj[name](args)`.
 */
extern JS_PUBLIC_API bool JS_CallFunctionName(JSContext* cx,
                                              JS::HandleObject obj,
                                              const char* name,
                                              const JS::HandleValueArray& args,
                                              JS::MutableHandleValue rval);

namespace JS {

static inline bool Call(JSContext* cx, JS::HandleObject thisObj,
                        JS::HandleFunction fun,
                        const JS::HandleValueArray& args,
                        MutableHandleValue rval) {
  return !!JS_CallFunction(cx, thisObj, fun, args, rval);
}

static inline bool Call(JSContext* cx, JS::HandleObject thisObj,
                        JS::HandleValue fun, const JS::HandleValueArray& args,
                        MutableHandleValue rval) {
  return !!JS_CallFunctionValue(cx, thisObj, fun, args, rval);
}

static inline bool Call(JSContext* cx, JS::HandleObject thisObj,
                        const char* name, const JS::HandleValueArray& args,
                        MutableHandleValue rval) {
  return !!JS_CallFunctionName(cx, thisObj, name, args, rval);
}

extern JS_PUBLIC_API bool Call(JSContext* cx, JS::HandleValue thisv,
                               JS::HandleValue fun,
                               const JS::HandleValueArray& args,
                               MutableHandleValue rval);

static inline bool Call(JSContext* cx, JS::HandleValue thisv,
                        JS::HandleObject funObj,
                        const JS::HandleValueArray& args,
                        MutableHandleValue rval) {
  MOZ_ASSERT(funObj);
  JS::RootedValue fun(cx, JS::ObjectValue(*funObj));
  return Call(cx, thisv, fun, args, rval);
}

/**
 * Invoke a constructor. This is the C++ equivalent of
 * `rval = Reflect.construct(fun, args, newTarget)`.
 *
 * JS::Construct() takes a `newTarget` argument that most callers don't need.
 * Consider using the four-argument Construct signature instead. (But if you're
 * implementing a subclass or a proxy handler's construct() method, this is the
 * right function to call.)
 *
 * Implements: ES6 7.3.13 Construct(F, [argumentsList], [newTarget]).
 * Use this function to invoke the [[Construct]] internal method.
 */
extern JS_PUBLIC_API bool Construct(JSContext* cx, JS::HandleValue fun,
                                    HandleObject newTarget,
                                    const JS::HandleValueArray& args,
                                    MutableHandleObject objp);

/**
 * Invoke a constructor. This is the C++ equivalent of
 * `rval = new fun(...args)`.
 *
 * Implements: ES6 7.3.13 Construct(F, [argumentsList], [newTarget]), when
 * newTarget is omitted.
 */
extern JS_PUBLIC_API bool Construct(JSContext* cx, JS::HandleValue fun,
                                    const JS::HandleValueArray& args,
                                    MutableHandleObject objp);

} /* namespace JS */

/**
 * Invoke a constructor, like the JS expression `new ctor(...args)`. Returns
 * the new object, or null on error.
 */
extern JS_PUBLIC_API JSObject* JS_New(JSContext* cx, JS::HandleObject ctor,
                                      const JS::HandleValueArray& args);

/*** Other property-defining functions **************************************/

extern JS_PUBLIC_API JSObject* JS_DefineObject(JSContext* cx,
                                               JS::HandleObject obj,
                                               const char* name,
                                               const JSClass* clasp = nullptr,
                                               unsigned attrs = 0);

extern JS_PUBLIC_API bool JS_DefineConstDoubles(JSContext* cx,
                                                JS::HandleObject obj,
                                                const JSConstDoubleSpec* cds);

extern JS_PUBLIC_API bool JS_DefineConstIntegers(JSContext* cx,
                                                 JS::HandleObject obj,
                                                 const JSConstIntegerSpec* cis);

extern JS_PUBLIC_API bool JS_DefineProperties(JSContext* cx,
                                              JS::HandleObject obj,
                                              const JSPropertySpec* ps);

/* * */

extern JS_PUBLIC_API bool JS_AlreadyHasOwnPropertyById(JSContext* cx,
                                                       JS::HandleObject obj,
                                                       JS::HandleId id,
                                                       bool* foundp);

extern JS_PUBLIC_API bool JS_AlreadyHasOwnProperty(JSContext* cx,
                                                   JS::HandleObject obj,
                                                   const char* name,
                                                   bool* foundp);

extern JS_PUBLIC_API bool JS_AlreadyHasOwnUCProperty(JSContext* cx,
                                                     JS::HandleObject obj,
                                                     const char16_t* name,
                                                     size_t namelen,
                                                     bool* foundp);

extern JS_PUBLIC_API bool JS_AlreadyHasOwnElement(JSContext* cx,
                                                  JS::HandleObject obj,
                                                  uint32_t index, bool* foundp);

extern JS_PUBLIC_API JSObject* JS_NewArrayObject(
    JSContext* cx, const JS::HandleValueArray& contents);

extern JS_PUBLIC_API JSObject* JS_NewArrayObject(JSContext* cx, size_t length);

/**
 * Returns true and sets |*isArray| indicating whether |value| is an Array
 * object or a wrapper around one, otherwise returns false on failure.
 *
 * This method returns true with |*isArray == false| when passed a proxy whose
 * target is an Array, or when passed a revoked proxy.
 */
extern JS_PUBLIC_API bool JS_IsArrayObject(JSContext* cx, JS::HandleValue value,
                                           bool* isArray);

/**
 * Returns true and sets |*isArray| indicating whether |obj| is an Array object
 * or a wrapper around one, otherwise returns false on failure.
 *
 * This method returns true with |*isArray == false| when passed a proxy whose
 * target is an Array, or when passed a revoked proxy.
 */
extern JS_PUBLIC_API bool JS_IsArrayObject(JSContext* cx, JS::HandleObject obj,
                                           bool* isArray);

extern JS_PUBLIC_API bool JS_GetArrayLength(JSContext* cx,
                                            JS::Handle<JSObject*> obj,
                                            uint32_t* lengthp);

extern JS_PUBLIC_API bool JS_SetArrayLength(JSContext* cx,
                                            JS::Handle<JSObject*> obj,
                                            uint32_t length);

namespace JS {

/**
 * Returns true and sets |*isMap| indicating whether |obj| is an Map object
 * or a wrapper around one, otherwise returns false on failure.
 *
 * This method returns true with |*isMap == false| when passed a proxy whose
 * target is an Map, or when passed a revoked proxy.
 */
extern JS_PUBLIC_API bool IsMapObject(JSContext* cx, JS::HandleObject obj,
                                      bool* isMap);

/**
 * Returns true and sets |*isSet| indicating whether |obj| is an Set object
 * or a wrapper around one, otherwise returns false on failure.
 *
 * This method returns true with |*isSet == false| when passed a proxy whose
 * target is an Set, or when passed a revoked proxy.
 */
extern JS_PUBLIC_API bool IsSetObject(JSContext* cx, JS::HandleObject obj,
                                      bool* isSet);

} /* namespace JS */

/**
 * Assign 'undefined' to all of the object's non-reserved slots. Note: this is
 * done for all slots, regardless of the associated property descriptor.
 */
JS_PUBLIC_API void JS_SetAllNonReservedSlotsToUndefined(JSContext* cx,
                                                        JSObject* objArg);

/**
 * Create a new array buffer with the given contents. It must be legal to pass
 * these contents to free(). On success, the ownership is transferred to the
 * new array buffer.
 */
extern JS_PUBLIC_API JSObject* JS_NewArrayBufferWithContents(JSContext* cx,
                                                             size_t nbytes,
                                                             void* contents);

namespace JS {

using BufferContentsRefFunc = void (*)(void* contents, void* userData);

} /* namespace JS */

/**
 * Create a new array buffer with the given contents. The ref and unref
 * functions should increment or decrement the reference count of the contents.
 * These functions allow array buffers to be used with embedder objects that
 * use reference counting, for example. The contents must not be modified by
 * any reference holders, internal or external.
 *
 * On success, the new array buffer takes a reference, and |ref(contents,
 * refUserData)| will be called. When the array buffer is ready to be disposed
 * of, |unref(contents, refUserData)| will be called to release the array
 * buffer's reference on the contents.
 *
 * The ref and unref functions must not call any JSAPI functions that could
 * cause a garbage collection.
 *
 * The ref function is optional. If it is nullptr, the caller is responsible
 * for incrementing the reference count before passing the contents to this
 * function. This also allows using non-reference-counted contents that must be
 * freed with some function other than free().
 *
 * The ref function may also be called in case the buffer is cloned in some
 * way. Currently this is not used, but it may be in the future. If the ref
 * function is nullptr, any operation where an extra reference would otherwise
 * be taken, will either copy the data, or throw an exception.
 */
extern JS_PUBLIC_API JSObject* JS_NewExternalArrayBuffer(
    JSContext* cx, size_t nbytes, void* contents, JS::BufferContentsRefFunc ref,
    JS::BufferContentsRefFunc unref, void* refUserData = nullptr);

/**
 * Create a new array buffer with the given contents.  The array buffer does not
 * take ownership of contents, and JS_DetachArrayBuffer must be called before
 * the contents are disposed of.
 */
extern JS_PUBLIC_API JSObject* JS_NewArrayBufferWithExternalContents(
    JSContext* cx, size_t nbytes, void* contents);

/**
 * Steal the contents of the given array buffer. The array buffer has its
 * length set to 0 and its contents array cleared. The caller takes ownership
 * of the return value and must free it or transfer ownership via
 * JS_NewArrayBufferWithContents when done using it.
 */
extern JS_PUBLIC_API void* JS_StealArrayBufferContents(JSContext* cx,
                                                       JS::HandleObject obj);

/**
 * Returns a pointer to the ArrayBuffer |obj|'s data.  |obj| and its views will
 * store and expose the data in the returned pointer: assigning into the
 * returned pointer will affect values exposed by views of |obj| and vice versa.
 *
 * The caller must ultimately deallocate the returned pointer to avoid leaking.
 * The memory is *not* garbage-collected with |obj|.  These steps must be
 * followed to deallocate:
 *
 * 1. The ArrayBuffer |obj| must be detached using JS_DetachArrayBuffer.
 * 2. The returned pointer must be freed using JS_free.
 *
 * To perform step 1, callers *must* hold a reference to |obj| until they finish
 * using the returned pointer.  They *must not* attempt to let |obj| be GC'd,
 * then JS_free the pointer.
 *
 * If |obj| isn't an ArrayBuffer, this function returns null and reports an
 * error.
 */
extern JS_PUBLIC_API void* JS_ExternalizeArrayBufferContents(
    JSContext* cx, JS::HandleObject obj);

/**
 * Create a new mapped array buffer with the given memory mapped contents. It
 * must be legal to free the contents pointer by unmapping it. On success,
 * ownership is transferred to the new mapped array buffer.
 */
extern JS_PUBLIC_API JSObject* JS_NewMappedArrayBufferWithContents(
    JSContext* cx, size_t nbytes, void* contents);

/**
 * Create memory mapped array buffer contents.
 * Caller must take care of closing fd after calling this function.
 */
extern JS_PUBLIC_API void* JS_CreateMappedArrayBufferContents(int fd,
                                                              size_t offset,
                                                              size_t length);

/**
 * Release the allocated resource of mapped array buffer contents before the
 * object is created.
 * If a new object has been created by JS_NewMappedArrayBufferWithContents()
 * with this content, then JS_DetachArrayBuffer() should be used instead to
 * release the resource used by the object.
 */
extern JS_PUBLIC_API void JS_ReleaseMappedArrayBufferContents(void* contents,
                                                              size_t length);

extern JS_PUBLIC_API JS::Value JS_GetReservedSlot(JSObject* obj,
                                                  uint32_t index);

extern JS_PUBLIC_API void JS_SetReservedSlot(JSObject* obj, uint32_t index,
                                             const JS::Value& v);

/************************************************************************/

/*
 * Functions and scripts.
 */
extern JS_PUBLIC_API JSFunction* JS_NewFunction(JSContext* cx, JSNative call,
                                                unsigned nargs, unsigned flags,
                                                const char* name);

namespace JS {

extern JS_PUBLIC_API JSFunction* GetSelfHostedFunction(
    JSContext* cx, const char* selfHostedName, HandleId id, unsigned nargs);

/**
 * Create a new function based on the given JSFunctionSpec, *fs.
 * id is the result of a successful call to
 * `PropertySpecNameToPermanentId(cx, fs->name, &id)`.
 *
 * Unlike JS_DefineFunctions, this does not treat fs as an array.
 * *fs must not be JS_FS_END.
 */
extern JS_PUBLIC_API JSFunction* NewFunctionFromSpec(JSContext* cx,
                                                     const JSFunctionSpec* fs,
                                                     HandleId id);

} /* namespace JS */

extern JS_PUBLIC_API JSObject* JS_GetFunctionObject(JSFunction* fun);

/**
 * Return the function's identifier as a JSString, or null if fun is unnamed.
 * The returned string lives as long as fun, so you don't need to root a saved
 * reference to it if fun is well-connected or rooted, and provided you bound
 * the use of the saved reference by fun's lifetime.
 */
extern JS_PUBLIC_API JSString* JS_GetFunctionId(JSFunction* fun);

/**
 * Return a function's display name. This is the defined name if one was given
 * where the function was defined, or it could be an inferred name by the JS
 * engine in the case that the function was defined to be anonymous. This can
 * still return nullptr if a useful display name could not be inferred. The
 * same restrictions on rooting as those in JS_GetFunctionId apply.
 */
extern JS_PUBLIC_API JSString* JS_GetFunctionDisplayId(JSFunction* fun);

/*
 * Return the arity (length) of fun.
 */
extern JS_PUBLIC_API uint16_t JS_GetFunctionArity(JSFunction* fun);

/**
 * Infallible predicate to test whether obj is a function object (faster than
 * comparing obj's class name to "Function", but equivalent unless someone has
 * overwritten the "Function" identifier with a different constructor and then
 * created instances using that constructor that might be passed in as obj).
 */
extern JS_PUBLIC_API bool JS_ObjectIsFunction(JSContext* cx, JSObject* obj);

extern JS_PUBLIC_API bool JS_IsNativeFunction(JSObject* funobj, JSNative call);

/** Return whether the given function is a valid constructor. */
extern JS_PUBLIC_API bool JS_IsConstructor(JSFunction* fun);

extern JS_PUBLIC_API bool JS_DefineFunctions(JSContext* cx,
                                             JS::Handle<JSObject*> obj,
                                             const JSFunctionSpec* fs);

extern JS_PUBLIC_API JSFunction* JS_DefineFunction(
    JSContext* cx, JS::Handle<JSObject*> obj, const char* name, JSNative call,
    unsigned nargs, unsigned attrs);

extern JS_PUBLIC_API JSFunction* JS_DefineUCFunction(
    JSContext* cx, JS::Handle<JSObject*> obj, const char16_t* name,
    size_t namelen, JSNative call, unsigned nargs, unsigned attrs);

extern JS_PUBLIC_API JSFunction* JS_DefineFunctionById(
    JSContext* cx, JS::Handle<JSObject*> obj, JS::Handle<jsid> id,
    JSNative call, unsigned nargs, unsigned attrs);

extern JS_PUBLIC_API bool JS_IsFunctionBound(JSFunction* fun);

extern JS_PUBLIC_API JSObject* JS_GetBoundFunctionTarget(JSFunction* fun);

namespace JS {

/**
 * Clone a top-level function into cx's global. This function will dynamically
 * fail if funobj was lexically nested inside some other function.
 */
extern JS_PUBLIC_API JSObject* CloneFunctionObject(JSContext* cx,
                                                   HandleObject funobj);

/**
 * As above, but providing an explicit scope chain.  scopeChain must not include
 * the global object on it; that's implicit.  It needs to contain the other
 * objects that should end up on the clone's scope chain.
 */
extern JS_PUBLIC_API JSObject* CloneFunctionObject(
    JSContext* cx, HandleObject funobj, AutoObjectVector& scopeChain);

}  // namespace JS

/**
 * Given a buffer, return false if the buffer might become a valid
 * javascript statement with the addition of more lines.  Otherwise return
 * true.  The intent is to support interactive compilation - accumulate
 * lines in a buffer until JS_BufferIsCompilableUnit is true, then pass it to
 * the compiler.
 */
extern JS_PUBLIC_API bool JS_BufferIsCompilableUnit(JSContext* cx,
                                                    JS::Handle<JSObject*> obj,
                                                    const char* utf8,
                                                    size_t length);

/**
 * |script| will always be set. On failure, it will be set to nullptr.
 */
extern JS_PUBLIC_API bool JS_CompileScript(JSContext* cx, const char* ascii,
                                           size_t length,
                                           const JS::CompileOptions& options,
                                           JS::MutableHandleScript script);

/**
 * |script| will always be set. On failure, it will be set to nullptr.
 */
extern JS_PUBLIC_API bool JS_CompileUCScript(JSContext* cx,
                                             const char16_t* chars,
                                             size_t length,
                                             const JS::CompileOptions& options,
                                             JS::MutableHandleScript script);

extern JS_PUBLIC_API JSObject* JS_GetGlobalFromScript(JSScript* script);

extern JS_PUBLIC_API const char* JS_GetScriptFilename(JSScript* script);

extern JS_PUBLIC_API unsigned JS_GetScriptBaseLineNumber(JSContext* cx,
                                                         JSScript* script);

extern JS_PUBLIC_API JSScript* JS_GetFunctionScript(JSContext* cx,
                                                    JS::HandleFunction fun);

namespace JS {

/* Options for JavaScript compilation. */

/*
 * In the most common use case, a CompileOptions instance is allocated on the
 * stack, and holds non-owning references to non-POD option values: strings;
 * principals; objects; and so on. The code declaring the instance guarantees
 * that such option values will outlive the CompileOptions itself: objects are
 * otherwise rooted; principals have had their reference counts bumped; strings
 * will not be freed until the CompileOptions goes out of scope. In this
 * situation, CompileOptions only refers to things others own, so it can be
 * lightweight.
 *
 * In some cases, however, we need to hold compilation options with a
 * non-stack-like lifetime. For example, JS::CompileOffThread needs to save
 * compilation options where a worker thread can find them, and then return
 * immediately. The worker thread will come along at some later point, and use
 * the options.
 *
 * The compiler itself just needs to be able to access a collection of options;
 * it doesn't care who owns them, or what's keeping them alive. It does its own
 * addrefs/copies/tracing/etc.
 *
 * Furthermore, in some cases compile options are propagated from one entity to
 * another (e.g. from a script to a function defined in that script).  This
 * involves copying over some, but not all, of the options.
 *
 * So, we have a class hierarchy that reflects these four use cases:
 *
 * - TransitiveCompileOptions is the common base class, representing options
 *   that should get propagated from a script to functions defined in that
 *   script.  This is never instantiated directly.
 *
 * - ReadOnlyCompileOptions is the only subclass of TransitiveCompileOptions,
 *   representing a full set of compile options.  It can be used by code that
 *   simply needs to access options set elsewhere, like the compiler.  This,
 *   again, is never instantiated directly.
 *
 * - The usual CompileOptions class must be stack-allocated, and holds
 *   non-owning references to the filename, element, and so on. It's derived
 *   from ReadOnlyCompileOptions, so the compiler can use it.
 *
 * - OwningCompileOptions roots / copies / reference counts of all its values,
 *   and unroots / frees / releases them when it is destructed. It too is
 *   derived from ReadOnlyCompileOptions, so the compiler accepts it.
 */

enum class AsmJSOption : uint8_t { Enabled, Disabled, DisabledByDebugger };

/**
 * The common base class for the CompileOptions hierarchy.
 *
 * Use this in code that needs to propagate compile options from one compilation
 * unit to another.
 */
class JS_FRIEND_API TransitiveCompileOptions {
 protected:
  // The Web Platform allows scripts to be loaded from arbitrary cross-origin
  // sources. This allows an attack by which a malicious website loads a
  // sensitive file (say, a bank statement) cross-origin (using the user's
  // cookies), and sniffs the generated syntax errors (via a window.onerror
  // handler) for juicy morsels of its contents.
  //
  // To counter this attack, HTML5 specifies that script errors should be
  // sanitized ("muted") when the script is not same-origin with the global
  // for which it is loaded. Callers should set this flag for cross-origin
  // scripts, and it will be propagated appropriately to child scripts and
  // passed back in JSErrorReports.
  bool mutedErrors_;
  const char* filename_;
  const char* introducerFilename_;
  const char16_t* sourceMapURL_;

  TransitiveCompileOptions()
      : mutedErrors_(false),
        filename_(nullptr),
        introducerFilename_(nullptr),
        sourceMapURL_(nullptr),
        utf8(false),
        selfHostingMode(false),
        canLazilyParse(true),
        strictOption(false),
        extraWarningsOption(false),
        expressionClosuresOption(false),
        werrorOption(false),
        asmJSOption(AsmJSOption::Disabled),
        throwOnAsmJSValidationFailureOption(false),
        forceAsync(false),
        sourceIsLazy(false),
        allowHTMLComments(true),
        isProbablySystemOrAddonCode(false),
        hideScriptFromDebugger(false),
        introductionType(nullptr),
        introductionLineno(0),
        introductionOffset(0),
        hasIntroductionInfo(false) {}

  // Set all POD options (those not requiring reference counts, copies,
  // rooting, or other hand-holding) to their values in |rhs|.
  void copyPODTransitiveOptions(const TransitiveCompileOptions& rhs);

 public:
  // Read-only accessors for non-POD options. The proper way to set these
  // depends on the derived type.
  bool mutedErrors() const { return mutedErrors_; }
  const char* filename() const { return filename_; }
  const char* introducerFilename() const { return introducerFilename_; }
  const char16_t* sourceMapURL() const { return sourceMapURL_; }
  virtual JSObject* element() const = 0;
  virtual JSString* elementAttributeName() const = 0;
  virtual JSScript* introductionScript() const = 0;

  // POD options.
  bool utf8;
  bool selfHostingMode;
  bool canLazilyParse;
  bool strictOption;
  bool extraWarningsOption;
  bool expressionClosuresOption;
  bool werrorOption;
  AsmJSOption asmJSOption;
  bool throwOnAsmJSValidationFailureOption;
  bool forceAsync;
  bool sourceIsLazy;
  bool allowHTMLComments;
  bool isProbablySystemOrAddonCode;
  bool hideScriptFromDebugger;

  // |introductionType| is a statically allocated C string:
  // one of "eval", "Function", or "GeneratorFunction".
  const char* introductionType;
  unsigned introductionLineno;
  uint32_t introductionOffset;
  bool hasIntroductionInfo;

 private:
  void operator=(const TransitiveCompileOptions&) = delete;
};

/**
 * The class representing a full set of compile options.
 *
 * Use this in code that only needs to access compilation options created
 * elsewhere, like the compiler. Don't instantiate this class (the constructor
 * is protected anyway); instead, create instances only of the derived classes:
 * CompileOptions and OwningCompileOptions.
 */
class JS_FRIEND_API ReadOnlyCompileOptions : public TransitiveCompileOptions {
  friend class CompileOptions;

 protected:
  ReadOnlyCompileOptions()
      : TransitiveCompileOptions(),
        lineno(1),
        column(0),
        scriptSourceOffset(0),
        isRunOnce(false),
        nonSyntacticScope(false),
        noScriptRval(false) {}

  // Set all POD options (those not requiring reference counts, copies,
  // rooting, or other hand-holding) to their values in |rhs|.
  void copyPODOptions(const ReadOnlyCompileOptions& rhs);

 public:
  // Read-only accessors for non-POD options. The proper way to set these
  // depends on the derived type.
  bool mutedErrors() const { return mutedErrors_; }
  const char* filename() const { return filename_; }
  const char* introducerFilename() const { return introducerFilename_; }
  const char16_t* sourceMapURL() const { return sourceMapURL_; }
  virtual JSObject* element() const override = 0;
  virtual JSString* elementAttributeName() const override = 0;
  virtual JSScript* introductionScript() const override = 0;

  // POD options.
  unsigned lineno;
  unsigned column;
  // The offset within the ScriptSource's full uncompressed text of the first
  // character we're presenting for compilation with this CompileOptions.
  //
  // When we compile a LazyScript, we pass the compiler only the substring of
  // the source the lazy function occupies. With chunked decompression, we
  // may not even have the complete uncompressed source present in memory. But
  // parse node positions are offsets within the ScriptSource's full text,
  // and LazyScripts indicate their substring of the full source by its
  // starting and ending offsets within the full text. This
  // scriptSourceOffset field lets the frontend convert between these
  // offsets and offsets within the substring presented for compilation.
  unsigned scriptSourceOffset;
  // isRunOnce only applies to non-function scripts.
  bool isRunOnce;
  bool nonSyntacticScope;
  bool noScriptRval;

 private:
  void operator=(const ReadOnlyCompileOptions&) = delete;
};

/**
 * Compilation options, with dynamic lifetime. An instance of this type
 * makes a copy of / holds / roots all dynamically allocated resources
 * (principals; elements; strings) that it refers to. Its destructor frees
 * / drops / unroots them. This is heavier than CompileOptions, below, but
 * unlike CompileOptions, it can outlive any given stack frame.
 *
 * Note that this *roots* any JS values it refers to - they're live
 * unconditionally. Thus, instances of this type can't be owned, directly
 * or indirectly, by a JavaScript object: if any value that this roots ever
 * comes to refer to the object that owns this, then the whole cycle, and
 * anything else it entrains, will never be freed.
 */
class JS_FRIEND_API OwningCompileOptions : public ReadOnlyCompileOptions {
  PersistentRootedObject elementRoot;
  PersistentRootedString elementAttributeNameRoot;
  PersistentRootedScript introductionScriptRoot;

 public:
  // A minimal constructor, for use with OwningCompileOptions::copy.
  explicit OwningCompileOptions(JSContext* cx);
  ~OwningCompileOptions();

  JSObject* element() const override { return elementRoot; }
  JSString* elementAttributeName() const override {
    return elementAttributeNameRoot;
  }
  JSScript* introductionScript() const override {
    return introductionScriptRoot;
  }

  // Set this to a copy of |rhs|. Return false on OOM.
  bool copy(JSContext* cx, const ReadOnlyCompileOptions& rhs);

  /* These setters make copies of their string arguments, and are fallible. */
  bool setFile(JSContext* cx, const char* f);
  bool setFileAndLine(JSContext* cx, const char* f, unsigned l);
  bool setSourceMapURL(JSContext* cx, const char16_t* s);
  bool setIntroducerFilename(JSContext* cx, const char* s);

  /* These setters are infallible, and can be chained. */
  OwningCompileOptions& setLine(unsigned l) {
    lineno = l;
    return *this;
  }
  OwningCompileOptions& setElement(JSObject* e) {
    elementRoot = e;
    return *this;
  }
  OwningCompileOptions& setElementAttributeName(JSString* p) {
    elementAttributeNameRoot = p;
    return *this;
  }
  OwningCompileOptions& setIntroductionScript(JSScript* s) {
    introductionScriptRoot = s;
    return *this;
  }
  OwningCompileOptions& setMutedErrors(bool mute) {
    mutedErrors_ = mute;
    return *this;
  }
  OwningCompileOptions& setUTF8(bool u) {
    utf8 = u;
    return *this;
  }
  OwningCompileOptions& setColumn(unsigned c) {
    column = c;
    return *this;
  }
  OwningCompileOptions& setScriptSourceOffset(unsigned o) {
    scriptSourceOffset = o;
    return *this;
  }
  OwningCompileOptions& setIsRunOnce(bool once) {
    isRunOnce = once;
    return *this;
  }
  OwningCompileOptions& setNoScriptRval(bool nsr) {
    noScriptRval = nsr;
    return *this;
  }
  OwningCompileOptions& setSelfHostingMode(bool shm) {
    selfHostingMode = shm;
    return *this;
  }
  OwningCompileOptions& setCanLazilyParse(bool clp) {
    canLazilyParse = clp;
    return *this;
  }
  OwningCompileOptions& setSourceIsLazy(bool l) {
    sourceIsLazy = l;
    return *this;
  }
  OwningCompileOptions& setNonSyntacticScope(bool n) {
    nonSyntacticScope = n;
    return *this;
  }
  OwningCompileOptions& setIntroductionType(const char* t) {
    introductionType = t;
    return *this;
  }
  bool setIntroductionInfo(JSContext* cx, const char* introducerFn,
                           const char* intro, unsigned line, JSScript* script,
                           uint32_t offset) {
    if (!setIntroducerFilename(cx, introducerFn)) return false;
    introductionType = intro;
    introductionLineno = line;
    introductionScriptRoot = script;
    introductionOffset = offset;
    hasIntroductionInfo = true;
    return true;
  }

 private:
  void operator=(const CompileOptions& rhs) = delete;
};

/**
 * Compilation options stored on the stack. An instance of this type
 * simply holds references to dynamically allocated resources (element;
 * filename; source map URL) that are owned by something else. If you
 * create an instance of this type, it's up to you to guarantee that
 * everything you store in it will outlive it.
 */
class MOZ_STACK_CLASS JS_FRIEND_API CompileOptions final
    : public ReadOnlyCompileOptions {
  RootedObject elementRoot;
  RootedString elementAttributeNameRoot;
  RootedScript introductionScriptRoot;

 public:
  explicit CompileOptions(JSContext* cx);
  CompileOptions(JSContext* cx, const ReadOnlyCompileOptions& rhs)
      : ReadOnlyCompileOptions(),
        elementRoot(cx),
        elementAttributeNameRoot(cx),
        introductionScriptRoot(cx) {
    copyPODOptions(rhs);

    filename_ = rhs.filename();
    introducerFilename_ = rhs.introducerFilename();
    sourceMapURL_ = rhs.sourceMapURL();
    elementRoot = rhs.element();
    elementAttributeNameRoot = rhs.elementAttributeName();
    introductionScriptRoot = rhs.introductionScript();
  }

  CompileOptions(JSContext* cx, const TransitiveCompileOptions& rhs)
      : ReadOnlyCompileOptions(),
        elementRoot(cx),
        elementAttributeNameRoot(cx),
        introductionScriptRoot(cx) {
    copyPODTransitiveOptions(rhs);

    filename_ = rhs.filename();
    introducerFilename_ = rhs.introducerFilename();
    sourceMapURL_ = rhs.sourceMapURL();
    elementRoot = rhs.element();
    elementAttributeNameRoot = rhs.elementAttributeName();
    introductionScriptRoot = rhs.introductionScript();
  }

  JSObject* element() const override { return elementRoot; }
  JSString* elementAttributeName() const override {
    return elementAttributeNameRoot;
  }
  JSScript* introductionScript() const override {
    return introductionScriptRoot;
  }

  CompileOptions& setFile(const char* f) {
    filename_ = f;
    return *this;
  }
  CompileOptions& setLine(unsigned l) {
    lineno = l;
    return *this;
  }
  CompileOptions& setFileAndLine(const char* f, unsigned l) {
    filename_ = f;
    lineno = l;
    return *this;
  }
  CompileOptions& setSourceMapURL(const char16_t* s) {
    sourceMapURL_ = s;
    return *this;
  }
  CompileOptions& setElement(JSObject* e) {
    elementRoot = e;
    return *this;
  }
  CompileOptions& setElementAttributeName(JSString* p) {
    elementAttributeNameRoot = p;
    return *this;
  }
  CompileOptions& setIntroductionScript(JSScript* s) {
    introductionScriptRoot = s;
    return *this;
  }
  CompileOptions& setMutedErrors(bool mute) {
    mutedErrors_ = mute;
    return *this;
  }
  CompileOptions& setUTF8(bool u) {
    utf8 = u;
    return *this;
  }
  CompileOptions& setColumn(unsigned c) {
    column = c;
    return *this;
  }
  CompileOptions& setScriptSourceOffset(unsigned o) {
    scriptSourceOffset = o;
    return *this;
  }
  CompileOptions& setIsRunOnce(bool once) {
    isRunOnce = once;
    return *this;
  }
  CompileOptions& setNoScriptRval(bool nsr) {
    noScriptRval = nsr;
    return *this;
  }
  CompileOptions& setSelfHostingMode(bool shm) {
    selfHostingMode = shm;
    return *this;
  }
  CompileOptions& setCanLazilyParse(bool clp) {
    canLazilyParse = clp;
    return *this;
  }
  CompileOptions& setSourceIsLazy(bool l) {
    sourceIsLazy = l;
    return *this;
  }
  CompileOptions& setNonSyntacticScope(bool n) {
    nonSyntacticScope = n;
    return *this;
  }
  CompileOptions& setIntroductionType(const char* t) {
    introductionType = t;
    return *this;
  }
  CompileOptions& setIntroductionInfo(const char* introducerFn,
                                      const char* intro, unsigned line,
                                      JSScript* script, uint32_t offset) {
    introducerFilename_ = introducerFn;
    introductionType = intro;
    introductionLineno = line;
    introductionScriptRoot = script;
    introductionOffset = offset;
    hasIntroductionInfo = true;
    return *this;
  }
  CompileOptions& maybeMakeStrictMode(bool strict) {
    strictOption = strictOption || strict;
    return *this;
  }

 private:
  void operator=(const CompileOptions& rhs) = delete;
};

/**
 * |script| will always be set. On failure, it will be set to nullptr.
 */
extern JS_PUBLIC_API bool Compile(JSContext* cx,
                                  const ReadOnlyCompileOptions& options,
                                  SourceBufferHolder& srcBuf,
                                  JS::MutableHandleScript script);

extern JS_PUBLIC_API bool Compile(JSContext* cx,
                                  const ReadOnlyCompileOptions& options,
                                  const char* bytes, size_t length,
                                  JS::MutableHandleScript script);

extern JS_PUBLIC_API bool Compile(JSContext* cx,
                                  const ReadOnlyCompileOptions& options,
                                  const char16_t* chars, size_t length,
                                  JS::MutableHandleScript script);

extern JS_PUBLIC_API bool Compile(JSContext* cx,
                                  const ReadOnlyCompileOptions& options,
                                  FILE* file, JS::MutableHandleScript script);

extern JS_PUBLIC_API bool Compile(JSContext* cx,
                                  const ReadOnlyCompileOptions& options,
                                  const char* filename,
                                  JS::MutableHandleScript script);

extern JS_PUBLIC_API bool CompileForNonSyntacticScope(
    JSContext* cx, const ReadOnlyCompileOptions& options,
    SourceBufferHolder& srcBuf, JS::MutableHandleScript script);

extern JS_PUBLIC_API bool CompileForNonSyntacticScope(
    JSContext* cx, const ReadOnlyCompileOptions& options, const char* bytes,
    size_t length, JS::MutableHandleScript script);

extern JS_PUBLIC_API bool CompileForNonSyntacticScope(
    JSContext* cx, const ReadOnlyCompileOptions& options, const char16_t* chars,
    size_t length, JS::MutableHandleScript script);

extern JS_PUBLIC_API bool CompileForNonSyntacticScope(
    JSContext* cx, const ReadOnlyCompileOptions& options, FILE* file,
    JS::MutableHandleScript script);

extern JS_PUBLIC_API bool CompileForNonSyntacticScope(
    JSContext* cx, const ReadOnlyCompileOptions& options, const char* filename,
    JS::MutableHandleScript script);

extern JS_PUBLIC_API bool CanCompileOffThread(
    JSContext* cx, const ReadOnlyCompileOptions& options, size_t length);

extern JS_PUBLIC_API bool CanDecodeOffThread(
    JSContext* cx, const ReadOnlyCompileOptions& options, size_t length);

/*
 * Off thread compilation control flow.
 *
 * After successfully triggering an off thread compile of a script, the
 * callback will eventually be invoked with the specified data and a token
 * for the compilation. The callback will be invoked while off thread,
 * so must ensure that its operations are thread safe. Afterwards, one of the
 * following functions must be invoked on the runtime's active thread:
 *
 * - FinishOffThreadScript, to get the result script (or nullptr on failure).
 * - CancelOffThreadScript, to free the resources without creating a script.
 *
 * The characters passed in to CompileOffThread must remain live until the
 * callback is invoked, and the resulting script will be rooted until the call
 * to FinishOffThreadScript.
 */

extern JS_PUBLIC_API bool CompileOffThread(
    JSContext* cx, const ReadOnlyCompileOptions& options, const char16_t* chars,
    size_t length, OffThreadCompileCallback callback, void* callbackData);

extern JS_PUBLIC_API JSScript* FinishOffThreadScript(JSContext* cx,
                                                     void* token);

extern JS_PUBLIC_API void CancelOffThreadScript(JSContext* cx, void* token);

extern JS_PUBLIC_API bool CompileOffThreadModule(
    JSContext* cx, const ReadOnlyCompileOptions& options, const char16_t* chars,
    size_t length, OffThreadCompileCallback callback, void* callbackData);

extern JS_PUBLIC_API JSObject* FinishOffThreadModule(JSContext* cx,
                                                     void* token);

extern JS_PUBLIC_API void CancelOffThreadModule(JSContext* cx, void* token);

extern JS_PUBLIC_API bool DecodeOffThreadScript(
    JSContext* cx, const ReadOnlyCompileOptions& options,
    mozilla::Vector<uint8_t>& buffer /* TranscodeBuffer& */, size_t cursor,
    OffThreadCompileCallback callback, void* callbackData);

extern JS_PUBLIC_API bool DecodeOffThreadScript(
    JSContext* cx, const ReadOnlyCompileOptions& options,
    const mozilla::Range<uint8_t>& range /* TranscodeRange& */,
    OffThreadCompileCallback callback, void* callbackData);

extern JS_PUBLIC_API JSScript* FinishOffThreadScriptDecoder(JSContext* cx,
                                                            void* token);

extern JS_PUBLIC_API void CancelOffThreadScriptDecoder(JSContext* cx,
                                                       void* token);

extern JS_PUBLIC_API bool DecodeMultiOffThreadScripts(
    JSContext* cx, const ReadOnlyCompileOptions& options,
    mozilla::Vector<TranscodeSource>& sources,
    OffThreadCompileCallback callback, void* callbackData);

extern JS_PUBLIC_API bool FinishMultiOffThreadScriptsDecoder(
    JSContext* cx, void* token, JS::MutableHandle<JS::ScriptVector> scripts);

extern JS_PUBLIC_API void CancelMultiOffThreadScriptsDecoder(JSContext* cx,
                                                             void* token);

/**
 * Compile a function with envChain plus the global as its scope chain.
 * envChain must contain objects in the current compartment of cx.  The actual
 * scope chain used for the function will consist of With wrappers for those
 * objects, followed by the current global of the compartment cx is in.  This
 * global must not be explicitly included in the scope chain.
 */
extern JS_PUBLIC_API bool CompileFunction(JSContext* cx,
                                          AutoObjectVector& envChain,
                                          const ReadOnlyCompileOptions& options,
                                          const char* name, unsigned nargs,
                                          const char* const* argnames,
                                          const char16_t* chars, size_t length,
                                          JS::MutableHandleFunction fun);

/**
 * Same as above, but taking a SourceBufferHolder for the function body.
 */
extern JS_PUBLIC_API bool CompileFunction(JSContext* cx,
                                          AutoObjectVector& envChain,
                                          const ReadOnlyCompileOptions& options,
                                          const char* name, unsigned nargs,
                                          const char* const* argnames,
                                          SourceBufferHolder& srcBuf,
                                          JS::MutableHandleFunction fun);

/**
 * Same as above, but taking a const char * for the function body.
 */
extern JS_PUBLIC_API bool CompileFunction(JSContext* cx,
                                          AutoObjectVector& envChain,
                                          const ReadOnlyCompileOptions& options,
                                          const char* name, unsigned nargs,
                                          const char* const* argnames,
                                          const char* bytes, size_t length,
                                          JS::MutableHandleFunction fun);

/*
 * Associate an element wrapper and attribute name with a previously compiled
 * script, for debugging purposes. Calling this function is optional, but should
 * be done before script execution if it is required.
 */
extern JS_PUBLIC_API bool InitScriptSourceElement(
    JSContext* cx, HandleScript script, HandleObject element,
    HandleString elementAttrName = nullptr);

/*
 * For a script compiled with the hideScriptFromDebugger option, expose the
 * script to the debugger by calling the debugger's onNewScript hook.
 */
extern JS_PUBLIC_API void ExposeScriptToDebugger(JSContext* cx,
                                                 HandleScript script);

} /* namespace JS */

extern JS_PUBLIC_API JSString* JS_DecompileScript(JSContext* cx,
                                                  JS::Handle<JSScript*> script);

extern JS_PUBLIC_API JSString* JS_DecompileFunction(
    JSContext* cx, JS::Handle<JSFunction*> fun);

/*
 * NB: JS_ExecuteScript and the JS::Evaluate APIs come in two flavors: either
 * they use the global as the scope, or they take an AutoObjectVector of objects
 * to use as the scope chain.  In the former case, the global is also used as
 * the "this" keyword value and the variables object (ECMA parlance for where
 * 'var' and 'function' bind names) of the execution context for script.  In the
 * latter case, the first object in the provided list is used, unless the list
 * is empty, in which case the global is used.
 *
 * Why a runtime option?  The alternative is to add APIs duplicating those
 * for the other value of flags, and that doesn't seem worth the code bloat
 * cost.  Such new entry points would probably have less obvious names, too, so
 * would not tend to be used.  The ContextOptionsRef adjustment, OTOH, can be
 * more easily hacked into existing code that does not depend on the bug; such
 * code can continue to use the familiar JS::Evaluate, etc., entry points.
 */

/**
 * Evaluate a script in the scope of the current global of cx.
 */
extern JS_PUBLIC_API bool JS_ExecuteScript(JSContext* cx,
                                           JS::HandleScript script,
                                           JS::MutableHandleValue rval);

extern JS_PUBLIC_API bool JS_ExecuteScript(JSContext* cx,
                                           JS::HandleScript script);

/**
 * As above, but providing an explicit scope chain.  envChain must not include
 * the global object on it; that's implicit.  It needs to contain the other
 * objects that should end up on the script's scope chain.
 */
extern JS_PUBLIC_API bool JS_ExecuteScript(JSContext* cx,
                                           JS::AutoObjectVector& envChain,
                                           JS::HandleScript script,
                                           JS::MutableHandleValue rval);

extern JS_PUBLIC_API bool JS_ExecuteScript(JSContext* cx,
                                           JS::AutoObjectVector& envChain,
                                           JS::HandleScript script);

namespace JS {

/**
 * Like the above, but handles a cross-compartment script. If the script is
 * cross-compartment, it is cloned into the current compartment before
 * executing.
 */
extern JS_PUBLIC_API bool CloneAndExecuteScript(JSContext* cx,
                                                JS::Handle<JSScript*> script,
                                                JS::MutableHandleValue rval);

/**
 * Like CloneAndExecuteScript above, but allows executing under a non-syntactic
 * environment chain.
 */
extern JS_PUBLIC_API bool CloneAndExecuteScript(JSContext* cx,
                                                JS::AutoObjectVector& envChain,
                                                JS::Handle<JSScript*> script,
                                                JS::MutableHandleValue rval);

} /* namespace JS */

namespace JS {

/**
 * Evaluate the given source buffer in the scope of the current global of cx.
 */
extern JS_PUBLIC_API bool Evaluate(JSContext* cx,
                                   const ReadOnlyCompileOptions& options,
                                   SourceBufferHolder& srcBuf,
                                   JS::MutableHandleValue rval);

/**
 * As above, but providing an explicit scope chain.  envChain must not include
 * the global object on it; that's implicit.  It needs to contain the other
 * objects that should end up on the script's scope chain.
 */
extern JS_PUBLIC_API bool Evaluate(JSContext* cx, AutoObjectVector& envChain,
                                   const ReadOnlyCompileOptions& options,
                                   SourceBufferHolder& srcBuf,
                                   JS::MutableHandleValue rval);

/**
 * Evaluate the given character buffer in the scope of the current global of cx.
 */
extern JS_PUBLIC_API bool Evaluate(JSContext* cx,
                                   const ReadOnlyCompileOptions& options,
                                   const char16_t* chars, size_t length,
                                   JS::MutableHandleValue rval);

/**
 * As above, but providing an explicit scope chain.  envChain must not include
 * the global object on it; that's implicit.  It needs to contain the other
 * objects that should end up on the script's scope chain.
 */
extern JS_PUBLIC_API bool Evaluate(JSContext* cx, AutoObjectVector& envChain,
                                   const ReadOnlyCompileOptions& options,
                                   const char16_t* chars, size_t length,
                                   JS::MutableHandleValue rval);

/**
 * Evaluate the given byte buffer in the scope of the current global of cx.
 */
extern JS_PUBLIC_API bool Evaluate(JSContext* cx,
                                   const ReadOnlyCompileOptions& options,
                                   const char* bytes, size_t length,
                                   JS::MutableHandleValue rval);

/**
 * Evaluate the given file in the scope of the current global of cx.
 */
extern JS_PUBLIC_API bool Evaluate(JSContext* cx,
                                   const ReadOnlyCompileOptions& options,
                                   const char* filename,
                                   JS::MutableHandleValue rval);

/**
 * Get the HostResolveImportedModule hook for a global.
 */
extern JS_PUBLIC_API JSFunction* GetModuleResolveHook(JSContext* cx);

/**
 * Set the HostResolveImportedModule hook for a global to the given function.
 */
extern JS_PUBLIC_API void SetModuleResolveHook(JSContext* cx,
                                               JS::HandleFunction func);

/**
 * Parse the given source buffer as a module in the scope of the current global
 * of cx and return a source text module record.
 */
extern JS_PUBLIC_API bool CompileModule(JSContext* cx,
                                        const ReadOnlyCompileOptions& options,
                                        SourceBufferHolder& srcBuf,
                                        JS::MutableHandleObject moduleRecord);

/**
 * Set the [[HostDefined]] field of a source text module record to the given
 * value.
 */
extern JS_PUBLIC_API void SetModuleHostDefinedField(JSObject* module,
                                                    const JS::Value& value);

/**
 * Get the [[HostDefined]] field of a source text module record.
 */
extern JS_PUBLIC_API JS::Value GetModuleHostDefinedField(JSObject* module);

/*
 * Perform the ModuleInstantiate operation on the given source text module
 * record.
 *
 * This transitively resolves all module dependencies (calling the
 * HostResolveImportedModule hook) and initializes the environment record for
 * the module.
 */
extern JS_PUBLIC_API bool ModuleInstantiate(JSContext* cx,
                                            JS::HandleObject moduleRecord);

/*
 * Perform the ModuleEvaluate operation on the given source text module record.
 *
 * This does nothing if this module has already been evaluated. Otherwise, it
 * transitively evaluates all dependences of this module and then evaluates this
 * module.
 *
 * ModuleInstantiate must have completed prior to calling this.
 */
extern JS_PUBLIC_API bool ModuleEvaluate(JSContext* cx,
                                         JS::HandleObject moduleRecord);

/*
 * Get a list of the module specifiers used by a source text module
 * record to request importation of modules.
 *
 * The result is a JavaScript array of object values.  To extract the individual
 * values use only JS_GetArrayLength and JS_GetElement with indices 0 to length
 * - 1.
 *
 * The element values are objects with the following properties:
 *  - moduleSpecifier: the module specifier string
 *  - lineNumber: the line number of the import in the source text
 *  - columnNumber: the column number of the import in the source text
 *
 * These property values can be extracted with GetRequestedModuleSpecifier() and
 * GetRequestedModuleSourcePos()
 */
extern JS_PUBLIC_API JSObject* GetRequestedModules(
    JSContext* cx, JS::HandleObject moduleRecord);

extern JS_PUBLIC_API JSString* GetRequestedModuleSpecifier(
    JSContext* cx, JS::HandleValue requestedModuleObject);

extern JS_PUBLIC_API void GetRequestedModuleSourcePos(
    JSContext* cx, JS::HandleValue requestedModuleObject, uint32_t* lineNumber,
    uint32_t* columnNumber);

extern JS_PUBLIC_API JSScript* GetModuleScript(JS::HandleObject moduleRecord);

} /* namespace JS */

extern JS_PUBLIC_API bool JS_CheckForInterrupt(JSContext* cx);

/*
 * These functions allow setting an interrupt callback that will be called
 * from the JS thread some time after any thread triggered the callback using
 * JS_RequestInterruptCallback(cx).
 *
 * To schedule the GC and for other activities the engine internally triggers
 * interrupt callbacks. The embedding should thus not rely on callbacks being
 * triggered through the external API only.
 *
 * Important note: Additional callbacks can occur inside the callback handler
 * if it re-enters the JS engine. The embedding must ensure that the callback
 * is disconnected before attempting such re-entry.
 */
extern JS_PUBLIC_API bool JS_AddInterruptCallback(JSContext* cx,
                                                  JSInterruptCallback callback);

extern JS_PUBLIC_API bool JS_DisableInterruptCallback(JSContext* cx);

extern JS_PUBLIC_API void JS_ResetInterruptCallback(JSContext* cx, bool enable);

extern JS_PUBLIC_API void JS_RequestInterruptCallback(JSContext* cx);

extern JS_PUBLIC_API void JS_RequestInterruptCallbackCanWait(JSContext* cx);

namespace JS {

/**
 * Sets the callback that's invoked whenever an incumbent global is required.
 *
 * SpiderMonkey doesn't itself have a notion of incumbent globals as defined
 * by the html spec, so we need the embedding to provide this.
 * See dom/base/ScriptSettings.h for details.
 */
extern JS_PUBLIC_API void SetGetIncumbentGlobalCallback(
    JSContext* cx, JSGetIncumbentGlobalCallback callback);

/**
 * Sets the callback that's invoked whenever a Promise job should be enqeued.
 *
 * SpiderMonkey doesn't schedule Promise resolution jobs itself; instead,
 * using this function the embedding can provide a callback to do that
 * scheduling. The provided `callback` is invoked with the promise job,
 * the corresponding Promise's allocation stack, and the `data` pointer
 * passed here as arguments.
 */
extern JS_PUBLIC_API void SetEnqueuePromiseJobCallback(
    JSContext* cx, JSEnqueuePromiseJobCallback callback, void* data = nullptr);

/**
 * Sets the callback that's invoked whenever a Promise is rejected without
 * a rejection handler, and when a Promise that was previously rejected
 * without a handler gets a handler attached.
 */
extern JS_PUBLIC_API void SetPromiseRejectionTrackerCallback(
    JSContext* cx, JSPromiseRejectionTrackerCallback callback,
    void* data = nullptr);

/**
 * Returns a new instance of the Promise builtin class in the current
 * compartment, with the right slot layout.
 *
 * The `executor` can be a `nullptr`. In that case, the only way to resolve or
 * reject the returned promise is via the `JS::ResolvePromise` and
 * `JS::RejectPromise` JSAPI functions.
 *
 * If a `proto` is passed, that gets set as the instance's [[Prototype]]
 * instead of the original value of `Promise.prototype`.
 */
extern JS_PUBLIC_API JSObject* NewPromiseObject(
    JSContext* cx, JS::HandleObject executor, JS::HandleObject proto = nullptr);

/**
 * Returns true if the given object is an unwrapped PromiseObject, false
 * otherwise.
 */
extern JS_PUBLIC_API bool IsPromiseObject(JS::HandleObject obj);

/**
 * Returns the current compartment's original Promise constructor.
 */
extern JS_PUBLIC_API JSObject* GetPromiseConstructor(JSContext* cx);

/**
 * Returns the current compartment's original Promise.prototype.
 */
extern JS_PUBLIC_API JSObject* GetPromisePrototype(JSContext* cx);

// Keep this in sync with the PROMISE_STATE defines in SelfHostingDefines.h.
enum class PromiseState { Pending, Fulfilled, Rejected };

/**
 * Returns the given Promise's state as a JS::PromiseState enum value.
 *
 * Returns JS::PromiseState::Pending if the given object is a wrapper that
 * can't safely be unwrapped.
 */
extern JS_PUBLIC_API PromiseState GetPromiseState(JS::HandleObject promise);

/**
 * Returns the given Promise's process-unique ID.
 */
JS_PUBLIC_API uint64_t GetPromiseID(JS::HandleObject promise);

/**
 * Returns the given Promise's result: either the resolution value for
 * fulfilled promises, or the rejection reason for rejected ones.
 */
extern JS_PUBLIC_API JS::Value GetPromiseResult(JS::HandleObject promise);

/**
 * Returns a js::SavedFrame linked list of the stack that lead to the given
 * Promise's allocation.
 */
extern JS_PUBLIC_API JSObject* GetPromiseAllocationSite(
    JS::HandleObject promise);

extern JS_PUBLIC_API JSObject* GetPromiseResolutionSite(
    JS::HandleObject promise);

#ifdef DEBUG
extern JS_PUBLIC_API void DumpPromiseAllocationSite(JSContext* cx,
                                                    JS::HandleObject promise);

extern JS_PUBLIC_API void DumpPromiseResolutionSite(JSContext* cx,
                                                    JS::HandleObject promise);
#endif

/**
 * Calls the current compartment's original Promise.resolve on the original
 * Promise constructor, with `resolutionValue` passed as an argument.
 */
extern JS_PUBLIC_API JSObject* CallOriginalPromiseResolve(
    JSContext* cx, JS::HandleValue resolutionValue);

/**
 * Calls the current compartment's original Promise.reject on the original
 * Promise constructor, with `resolutionValue` passed as an argument.
 */
extern JS_PUBLIC_API JSObject* CallOriginalPromiseReject(
    JSContext* cx, JS::HandleValue rejectionValue);

/**
 * Resolves the given Promise with the given `resolutionValue`.
 *
 * Calls the `resolve` function that was passed to the executor function when
 * the Promise was created.
 */
extern JS_PUBLIC_API bool ResolvePromise(JSContext* cx,
                                         JS::HandleObject promiseObj,
                                         JS::HandleValue resolutionValue);

/**
 * Rejects the given `promise` with the given `rejectionValue`.
 *
 * Calls the `reject` function that was passed to the executor function when
 * the Promise was created.
 */
extern JS_PUBLIC_API bool RejectPromise(JSContext* cx,
                                        JS::HandleObject promiseObj,
                                        JS::HandleValue rejectionValue);

/**
 * Calls the current compartment's original Promise.prototype.then on the
 * given `promise`, with `onResolve` and `onReject` passed as arguments.
 *
 * Asserts if the passed-in `promise` object isn't an unwrapped instance of
 * `Promise` or a subclass or `onResolve` and `onReject` aren't both either
 * `nullptr` or callable objects.
 */
extern JS_PUBLIC_API JSObject* CallOriginalPromiseThen(
    JSContext* cx, JS::HandleObject promise, JS::HandleObject onResolve,
    JS::HandleObject onReject);

/**
 * Unforgeable, optimized version of the JS builtin Promise.prototype.then.
 *
 * Takes a Promise instance and `onResolve`, `onReject` callables to enqueue
 * as reactions for that promise. In difference to Promise.prototype.then,
 * this doesn't create and return a new Promise instance.
 *
 * Asserts if the passed-in `promise` object isn't an unwrapped instance of
 * `Promise` or a subclass or `onResolve` and `onReject` aren't both callable
 * objects.
 */
extern JS_PUBLIC_API bool AddPromiseReactions(JSContext* cx,
                                              JS::HandleObject promise,
                                              JS::HandleObject onResolve,
                                              JS::HandleObject onReject);

/**
 * Unforgeable version of the JS builtin Promise.all.
 *
 * Takes an AutoObjectVector of Promise objects and returns a promise that's
 * resolved with an array of resolution values when all those promises have
 * been resolved, or rejected with the rejection value of the first rejected
 * promise.
 *
 * Asserts that all objects in the `promises` vector are, maybe wrapped,
 * instances of `Promise` or a subclass of `Promise`.
 */
extern JS_PUBLIC_API JSObject* GetWaitForAllPromise(
    JSContext* cx, const JS::AutoObjectVector& promises);

/**
 * The Dispatchable interface allows the embedding to call SpiderMonkey
 * on a JSContext thread when requested via DispatchToEventLoopCallback.
 */
class JS_PUBLIC_API Dispatchable {
 protected:
  // Dispatchables are created and destroyed by SpiderMonkey.
  Dispatchable() = default;
  virtual ~Dispatchable() = default;

 public:
  // ShuttingDown indicates that SpiderMonkey should abort async tasks to
  // expedite shutdown.
  enum MaybeShuttingDown { NotShuttingDown, ShuttingDown };

  // Called by the embedding after DispatchToEventLoopCallback succeeds.
  virtual void run(JSContext* cx, MaybeShuttingDown maybeShuttingDown) = 0;
};

/**
 * DispatchToEventLoopCallback may be called from any thread, being passed the
 * same 'closure' passed to InitDispatchToEventLoop() and Dispatchable from the
 * same JSRuntime. If the embedding returns 'true', the embedding must call
 * Dispatchable::run() on an active JSContext thread for the same JSRuntime on
 * which 'closure' was registered. If DispatchToEventLoopCallback returns
 * 'false', SpiderMonkey will assume a shutdown of the JSRuntime is in progress.
 * This contract implies that, by the time the final JSContext is destroyed in
 * the JSRuntime, the embedding must have (1) run all Dispatchables for which
 * DispatchToEventLoopCallback returned true, (2) already started returning
 * false from calls to DispatchToEventLoopCallback.
 */

typedef bool (*DispatchToEventLoopCallback)(void* closure,
                                            Dispatchable* dispatchable);

extern JS_PUBLIC_API void InitDispatchToEventLoop(
    JSContext* cx, DispatchToEventLoopCallback callback, void* closure);

/**
 * The ConsumeStreamCallback is called from an active JSContext, passing a
 * StreamConsumer that wishes to consume the given host object as a stream of
 * bytes with the given MIME type. On failure, the embedding must report the
 * appropriate error on 'cx'. On success, the embedding must call
 * consumer->consumeChunk() repeatedly on any thread until exactly one of:
 *  - consumeChunk() returns false
 *  - the embedding calls consumer->streamClosed()
 * before JS_DestroyContext(cx) or JS::ShutdownAsyncTasks(cx) is called.
 *
 * Note: consumeChunk() and streamClosed() may be called synchronously by
 * ConsumeStreamCallback.
 */

class JS_PUBLIC_API StreamConsumer {
 protected:
  // AsyncStreamConsumers are created and destroyed by SpiderMonkey.
  StreamConsumer() = default;
  virtual ~StreamConsumer() = default;

 public:
  // Called by the embedding as each chunk of bytes becomes available.
  // If this function returns 'false', the stream must drop all pointers to
  // this StreamConsumer.
  virtual bool consumeChunk(const uint8_t* begin, size_t length) = 0;

  // Called by the embedding when the stream is closed according to the
  // contract described above.
  enum CloseReason { EndOfFile, Error };
  virtual void streamClosed(CloseReason reason) = 0;

  // Provides optional stream attributes such as base or source mapping URLs.
  // Necessarily called before consumeChunk() or streamClosed(). The caller
  // retains ownership of the given strings.
  virtual void noteResponseURLs(const char* maybeUrl,
                                const char* maybeSourceMapUrl) = 0;
};

enum class MimeType { Wasm };

typedef bool (*ConsumeStreamCallback)(JSContext* cx, JS::HandleObject obj,
                                      MimeType mimeType,
                                      StreamConsumer* consumer);

extern JS_PUBLIC_API void InitConsumeStreamCallback(
    JSContext* cx, ConsumeStreamCallback callback);

/**
 * When a JSRuntime is destroyed it implicitly cancels all async tasks in
 * progress, releasing any roots held by the task. However, this is not soon
 * enough for cycle collection, which needs to have roots dropped earlier so
 * that the cycle collector can transitively remove roots for a future GC. For
 * these and other cases, the set of pending async tasks can be canceled
 * with this call earlier than JSRuntime destruction.
 */

extern JS_PUBLIC_API void ShutdownAsyncTasks(JSContext* cx);

/**
 * Supply an alternative stack to incorporate into captured SavedFrame
 * backtraces as the imputed caller of asynchronous JavaScript calls, like async
 * function resumptions and DOM callbacks.
 *
 * When one async function awaits the result of another, it's natural to think
 * of that as a sort of function call: just as execution resumes from an
 * ordinary call expression when the callee returns, with the return value
 * providing the value of the call expression, execution resumes from an 'await'
 * expression after the awaited asynchronous function call returns, passing the
 * return value along.
 *
 * Call the two async functions in such a situation the 'awaiter' and the
 * 'awaitee'.
 *
 * As an async function, the awaitee contains 'await' expressions of its own.
 * Whenever it executes after its first 'await', there are never any actual
 * frames on the JavaScript stack under it; its awaiter is certainly not there.
 * An await expression's continuation is invoked as a promise callback, and
 * those are always called directly from the event loop in their own microtick.
 * (Ignore unusual cases like nested event loops.)
 *
 * But because await expressions bear such a strong resemblance to calls (and
 * deliberately so!), it would be unhelpful for stacks captured within the
 * awaitee to be empty; instead, they should present the awaiter as the caller.
 *
 * The AutoSetAsyncStackForNewCalls RAII class supplies a SavedFrame stack to
 * treat as the caller of any JavaScript invocations that occur within its
 * lifetime. Any SavedFrame stack captured during such an invocation uses the
 * SavedFrame passed to the constructor's 'stack' parameter as the 'asyncParent'
 * property of the SavedFrame for the invocation's oldest frame. Its 'parent'
 * property will be null, so stack-walking code can distinguish this
 * awaiter/awaitee transition from an ordinary caller/callee transition.
 *
 * The constructor's 'asyncCause' parameter supplies a string explaining what
 * sort of asynchronous call caused 'stack' to be spliced into the backtrace;
 * for example, async function resumptions use the string "async". This appears
 * as the 'asyncCause' property of the 'asyncParent' SavedFrame.
 *
 * Async callers are distinguished in the string form of a SavedFrame chain by
 * including the 'asyncCause' string in the frame. It appears before the
 * function name, with the two separated by a '*'.
 *
 * Note that, as each compartment has its own set of SavedFrames, the
 * 'asyncParent' may actually point to a copy of 'stack', rather than the exact
 * SavedFrame object passed.
 *
 * The youngest frame of 'stack' is not mutated to take the asyncCause string as
 * its 'asyncCause' property; SavedFrame objects are immutable. Rather, a fresh
 * clone of the frame is created with the needed 'asyncCause' property.
 *
 * The 'kind' argument specifies how aggressively 'stack' supplants any
 * JavaScript frames older than this AutoSetAsyncStackForNewCalls object. If
 * 'kind' is 'EXPLICIT', then all captured SavedFrame chains take on 'stack' as
 * their 'asyncParent' where the chain crosses this object's scope. If 'kind' is
 * 'IMPLICIT', then 'stack' is only included in captured chains if there are no
 * other JavaScript frames on the stack --- that is, only if the stack would
 * otherwise end at that point.
 *
 * AutoSetAsyncStackForNewCalls affects only SavedFrame chains; it does not
 * affect Debugger.Frame or js::FrameIter. SavedFrame chains are used for
 * Error.stack, allocation profiling, Promise debugging, and so on.
 *
 * See also `js/src/doc/SavedFrame/SavedFrame.md` for documentation on async
 * stack frames.
 */
class MOZ_STACK_CLASS JS_PUBLIC_API AutoSetAsyncStackForNewCalls {
  JSContext* cx;
  RootedObject oldAsyncStack;
  const char* oldAsyncCause;
  bool oldAsyncCallIsExplicit;

 public:
  enum class AsyncCallKind {
    // The ordinary kind of call, where we may apply an async
    // parent if there is no ordinary parent.
    IMPLICIT,
    // An explicit async parent, e.g., callFunctionWithAsyncStack,
    // where we always want to override any ordinary parent.
    EXPLICIT
  };

  // The stack parameter cannot be null by design, because it would be
  // ambiguous whether that would clear any scheduled async stack and make the
  // normal stack reappear in the new call, or just keep the async stack
  // already scheduled for the new call, if any.
  //
  // asyncCause is owned by the caller and its lifetime must outlive the
  // lifetime of the AutoSetAsyncStackForNewCalls object. It is strongly
  // encouraged that asyncCause be a string constant or similar statically
  // allocated string.
  AutoSetAsyncStackForNewCalls(JSContext* cx, HandleObject stack,
                               const char* asyncCause,
                               AsyncCallKind kind = AsyncCallKind::IMPLICIT);
  ~AutoSetAsyncStackForNewCalls();
};

}  // namespace JS

/************************************************************************/

/*
 * Strings.
 *
 * NB: JS_NewUCString takes ownership of bytes on success, avoiding a copy;
 * but on error (signified by null return), it leaves chars owned by the
 * caller. So the caller must free bytes in the error case, if it has no use
 * for them. In contrast, all the JS_New*StringCopy* functions do not take
 * ownership of the character memory passed to them -- they copy it.
 */
extern JS_PUBLIC_API JSString* JS_NewStringCopyN(JSContext* cx, const char* s,
                                                 size_t n);

extern JS_PUBLIC_API JSString* JS_NewStringCopyZ(JSContext* cx, const char* s);

extern JS_PUBLIC_API JSString* JS_NewStringCopyUTF8Z(
    JSContext* cx, const JS::ConstUTF8CharsZ s);

extern JS_PUBLIC_API JSString* JS_NewStringCopyUTF8N(JSContext* cx,
                                                     const JS::UTF8Chars s);

extern JS_PUBLIC_API JSString* JS_AtomizeAndPinJSString(JSContext* cx,
                                                        JS::HandleString str);

extern JS_PUBLIC_API JSString* JS_AtomizeStringN(JSContext* cx, const char* s,
                                                 size_t length);

extern JS_PUBLIC_API JSString* JS_AtomizeString(JSContext* cx, const char* s);

extern JS_PUBLIC_API JSString* JS_AtomizeAndPinStringN(JSContext* cx,
                                                       const char* s,
                                                       size_t length);

extern JS_PUBLIC_API JSString* JS_AtomizeAndPinString(JSContext* cx,
                                                      const char* s);

extern JS_PUBLIC_API JSString* JS_NewLatin1String(JSContext* cx,
                                                  JS::Latin1Char* chars,
                                                  size_t length);

extern JS_PUBLIC_API JSString* JS_NewUCString(JSContext* cx, char16_t* chars,
                                              size_t length);

extern JS_PUBLIC_API JSString* JS_NewUCStringCopyN(JSContext* cx,
                                                   const char16_t* s, size_t n);

extern JS_PUBLIC_API JSString* JS_NewUCStringCopyZ(JSContext* cx,
                                                   const char16_t* s);

extern JS_PUBLIC_API JSString* JS_AtomizeUCStringN(JSContext* cx,
                                                   const char16_t* s,
                                                   size_t length);

extern JS_PUBLIC_API JSString* JS_AtomizeUCString(JSContext* cx,
                                                  const char16_t* s);

extern JS_PUBLIC_API JSString* JS_AtomizeAndPinUCStringN(JSContext* cx,
                                                         const char16_t* s,
                                                         size_t length);

extern JS_PUBLIC_API JSString* JS_AtomizeAndPinUCString(JSContext* cx,
                                                        const char16_t* s);

extern JS_PUBLIC_API bool JS_CompareStrings(JSContext* cx, JSString* str1,
                                            JSString* str2, int32_t* result);

extern JS_PUBLIC_API bool JS_StringEqualsAscii(JSContext* cx, JSString* str,
                                               const char* asciiBytes,
                                               bool* match);

extern JS_PUBLIC_API size_t JS_PutEscapedString(JSContext* cx, char* buffer,
                                                size_t size, JSString* str,
                                                char quote);

extern JS_PUBLIC_API bool JS_FileEscapedString(FILE* fp, JSString* str,
                                               char quote);

/*
 * Extracting string characters and length.
 *
 * While getting the length of a string is infallible, getting the chars can
 * fail. As indicated by the lack of a JSContext parameter, there are two
 * special cases where getting the chars is infallible:
 *
 * The first case is for strings that have been atomized, e.g. directly by
 * JS_AtomizeAndPinString or implicitly because it is stored in a jsid.
 *
 * The second case is "flat" strings that have been explicitly prepared in a
 * fallible context by JS_FlattenString. To catch errors, a separate opaque
 * JSFlatString type is returned by JS_FlattenString and expected by
 * JS_GetFlatStringChars. Note, though, that this is purely a syntactic
 * distinction: the input and output of JS_FlattenString are the same actual
 * GC-thing. If a JSString is known to be flat, JS_ASSERT_STRING_IS_FLAT can be
 * used to make a debug-checked cast. Example:
 *
 *   // in a fallible context
 *   JSFlatString* fstr = JS_FlattenString(cx, str);
 *   if (!fstr)
 *     return false;
 *   MOZ_ASSERT(fstr == JS_ASSERT_STRING_IS_FLAT(str));
 *
 *   // in an infallible context, for the same 'str'
 *   AutoCheckCannotGC nogc;
 *   const char16_t* chars = JS_GetTwoByteFlatStringChars(nogc, fstr)
 *   MOZ_ASSERT(chars);
 *
 * Flat strings and interned strings are always null-terminated, so
 * JS_FlattenString can be used to get a null-terminated string.
 *
 * Additionally, string characters are stored as either Latin1Char (8-bit)
 * or char16_t (16-bit). Clients can use JS_StringHasLatin1Chars and can then
 * call either the Latin1* or TwoByte* functions. Some functions like
 * JS_CopyStringChars and JS_GetStringCharAt accept both Latin1 and TwoByte
 * strings.
 */

extern JS_PUBLIC_API size_t JS_GetStringLength(JSString* str);

extern JS_PUBLIC_API bool JS_StringIsFlat(JSString* str);

/** Returns true iff the string's characters are stored as Latin1. */
extern JS_PUBLIC_API bool JS_StringHasLatin1Chars(JSString* str);

extern JS_PUBLIC_API const JS::Latin1Char* JS_GetLatin1StringCharsAndLength(
    JSContext* cx, const JS::AutoRequireNoGC& nogc, JSString* str,
    size_t* length);

extern JS_PUBLIC_API const char16_t* JS_GetTwoByteStringCharsAndLength(
    JSContext* cx, const JS::AutoRequireNoGC& nogc, JSString* str,
    size_t* length);

extern JS_PUBLIC_API bool JS_GetStringCharAt(JSContext* cx, JSString* str,
                                             size_t index, char16_t* res);

extern JS_PUBLIC_API char16_t JS_GetFlatStringCharAt(JSFlatString* str,
                                                     size_t index);

extern JS_PUBLIC_API const char16_t* JS_GetTwoByteExternalStringChars(
    JSString* str);

extern JS_PUBLIC_API bool JS_CopyStringChars(JSContext* cx,
                                             mozilla::Range<char16_t> dest,
                                             JSString* str);

extern JS_PUBLIC_API JSFlatString* JS_FlattenString(JSContext* cx,
                                                    JSString* str);

extern JS_PUBLIC_API const JS::Latin1Char* JS_GetLatin1FlatStringChars(
    const JS::AutoRequireNoGC& nogc, JSFlatString* str);

extern JS_PUBLIC_API const char16_t* JS_GetTwoByteFlatStringChars(
    const JS::AutoRequireNoGC& nogc, JSFlatString* str);

static MOZ_ALWAYS_INLINE JSFlatString* JSID_TO_FLAT_STRING(jsid id) {
  MOZ_ASSERT(JSID_IS_STRING(id));
  return (JSFlatString*)(JSID_BITS(id));
}

static MOZ_ALWAYS_INLINE JSFlatString* JS_ASSERT_STRING_IS_FLAT(JSString* str) {
  MOZ_ASSERT(JS_StringIsFlat(str));
  return (JSFlatString*)str;
}

static MOZ_ALWAYS_INLINE JSString* JS_FORGET_STRING_FLATNESS(
    JSFlatString* fstr) {
  return (JSString*)fstr;
}

/*
 * Additional APIs that avoid fallibility when given a flat string.
 */

extern JS_PUBLIC_API bool JS_FlatStringEqualsAscii(JSFlatString* str,
                                                   const char* asciiBytes);

extern JS_PUBLIC_API size_t JS_PutEscapedFlatString(char* buffer, size_t size,
                                                    JSFlatString* str,
                                                    char quote);

/**
 * Create a dependent string, i.e., a string that owns no character storage,
 * but that refers to a slice of another string's chars.  Dependent strings
 * are mutable by definition, so the thread safety comments above apply.
 */
extern JS_PUBLIC_API JSString* JS_NewDependentString(JSContext* cx,
                                                     JS::HandleString str,
                                                     size_t start,
                                                     size_t length);

/**
 * Concatenate two strings, possibly resulting in a rope.
 * See above for thread safety comments.
 */
extern JS_PUBLIC_API JSString* JS_ConcatStrings(JSContext* cx,
                                                JS::HandleString left,
                                                JS::HandleString right);

/**
 * For JS_DecodeBytes, set *dstlenp to the size of the destination buffer before
 * the call; on return, *dstlenp contains the number of characters actually
 * stored. To determine the necessary destination buffer size, make a sizing
 * call that passes nullptr for dst.
 *
 * On errors, the functions report the error. In that case, *dstlenp contains
 * the number of characters or bytes transferred so far.  If cx is nullptr, no
 * error is reported on failure, and the functions simply return false.
 *
 * NB: This function does not store an additional zero byte or char16_t after
 * the transcoded string.
 */
JS_PUBLIC_API bool JS_DecodeBytes(JSContext* cx, const char* src, size_t srclen,
                                  char16_t* dst, size_t* dstlenp);

/**
 * A variation on JS_EncodeCharacters where a null terminated string is
 * returned that you are expected to call JS_free on when done.
 */
JS_PUBLIC_API char* JS_EncodeString(JSContext* cx, JSString* str);

/**
 * Same behavior as JS_EncodeString(), but encode into UTF-8 string
 */
JS_PUBLIC_API char* JS_EncodeStringToUTF8(JSContext* cx, JS::HandleString str);

/**
 * Get number of bytes in the string encoding (without accounting for a
 * terminating zero bytes. The function returns (size_t) -1 if the string
 * can not be encoded into bytes and reports an error using cx accordingly.
 */
JS_PUBLIC_API size_t JS_GetStringEncodingLength(JSContext* cx, JSString* str);

/**
 * Encode string into a buffer. The function does not stores an additional
 * zero byte. The function returns (size_t) -1 if the string can not be
 * encoded into bytes with no error reported. Otherwise it returns the number
 * of bytes that are necessary to encode the string. If that exceeds the
 * length parameter, the string will be cut and only length bytes will be
 * written into the buffer.
 */
JS_PUBLIC_API size_t JS_EncodeStringToBuffer(JSContext* cx, JSString* str,
                                             char* buffer, size_t length);

class MOZ_RAII JSAutoByteString {
 public:
  JSAutoByteString(JSContext* cx, JSString* str MOZ_GUARD_OBJECT_NOTIFIER_PARAM)
      : mBytes(JS_EncodeString(cx, str)) {
    MOZ_ASSERT(cx);
    MOZ_GUARD_OBJECT_NOTIFIER_INIT;
  }

  explicit JSAutoByteString(MOZ_GUARD_OBJECT_NOTIFIER_ONLY_PARAM)
      : mBytes(nullptr) {
    MOZ_GUARD_OBJECT_NOTIFIER_INIT;
  }

  ~JSAutoByteString() { JS_free(nullptr, mBytes); }

  /* Take ownership of the given byte array. */
  void initBytes(JS::UniqueChars&& bytes) {
    MOZ_ASSERT(!mBytes);
    mBytes = bytes.release();
  }

  char* encodeLatin1(JSContext* cx, JSString* str) {
    MOZ_ASSERT(!mBytes);
    MOZ_ASSERT(cx);
    mBytes = JS_EncodeString(cx, str);
    return mBytes;
  }

  char* encodeUtf8(JSContext* cx, JS::HandleString str) {
    MOZ_ASSERT(!mBytes);
    MOZ_ASSERT(cx);
    mBytes = JS_EncodeStringToUTF8(cx, str);
    return mBytes;
  }

  void clear() {
    js_free(mBytes);
    mBytes = nullptr;
  }

  char* ptr() const { return mBytes; }

  bool operator!() const { return !mBytes; }

  size_t length() const {
    if (!mBytes) return 0;
    return strlen(mBytes);
  }

 private:
  char* mBytes;
  MOZ_DECL_USE_GUARD_OBJECT_NOTIFIER

  /* Copy and assignment are not supported. */
  JSAutoByteString(const JSAutoByteString& another);
  JSAutoByteString& operator=(const JSAutoByteString& another);
};

namespace JS {

extern JS_PUBLIC_API JSAddonId* NewAddonId(JSContext* cx, JS::HandleString str);

extern JS_PUBLIC_API JSString* StringOfAddonId(JSAddonId* id);

extern JS_PUBLIC_API JSAddonId* AddonIdOfObject(JSObject* obj);

}  // namespace JS

/************************************************************************/
/*
 * Symbols
 */

namespace JS {

/**
 * Create a new Symbol with the given description. This function never returns
 * a Symbol that is in the Runtime-wide symbol registry.
 *
 * If description is null, the new Symbol's [[Description]] attribute is
 * undefined.
 */
JS_PUBLIC_API Symbol* NewSymbol(JSContext* cx, HandleString description);

/**
 * Symbol.for as specified in ES6.
 *
 * Get a Symbol with the description 'key' from the Runtime-wide symbol
 * registry. If there is not already a Symbol with that description in the
 * registry, a new Symbol is created and registered. 'key' must not be null.
 */
JS_PUBLIC_API Symbol* GetSymbolFor(JSContext* cx, HandleString key);

/**
 * Get the [[Description]] attribute of the given symbol.
 *
 * This function is infallible. If it returns null, that means the symbol's
 * [[Description]] is undefined.
 */
JS_PUBLIC_API JSString* GetSymbolDescription(HandleSymbol symbol);

/* Well-known symbols. */
#define JS_FOR_EACH_WELL_KNOWN_SYMBOL(MACRO) \
  MACRO(isConcatSpreadable)                  \
  MACRO(iterator)                            \
  MACRO(match)                               \
  MACRO(replace)                             \
  MACRO(search)                              \
  MACRO(species)                             \
  MACRO(hasInstance)                         \
  MACRO(split)                               \
  MACRO(toPrimitive)                         \
  MACRO(toStringTag)                         \
  MACRO(unscopables)                         \
  MACRO(asyncIterator)

enum class SymbolCode : uint32_t {
// There is one SymbolCode for each well-known symbol.
#define JS_DEFINE_SYMBOL_ENUM(name) name,
  JS_FOR_EACH_WELL_KNOWN_SYMBOL(
      JS_DEFINE_SYMBOL_ENUM)  // SymbolCode::iterator, etc.
#undef JS_DEFINE_SYMBOL_ENUM
  Limit,
  InSymbolRegistry =
      0xfffffffe,            // created by Symbol.for() or JS::GetSymbolFor()
  UniqueSymbol = 0xffffffff  // created by Symbol() or JS::NewSymbol()
};

/* For use in loops that iterate over the well-known symbols. */
const size_t WellKnownSymbolLimit = size_t(SymbolCode::Limit);

/**
 * Return the SymbolCode telling what sort of symbol `symbol` is.
 *
 * A symbol's SymbolCode never changes once it is created.
 */
JS_PUBLIC_API SymbolCode GetSymbolCode(Handle<Symbol*> symbol);

/**
 * Get one of the well-known symbols defined by ES6. A single set of well-known
 * symbols is shared by all compartments in a JSRuntime.
 *
 * `which` must be in the range [0, WellKnownSymbolLimit).
 */
JS_PUBLIC_API Symbol* GetWellKnownSymbol(JSContext* cx, SymbolCode which);

/**
 * Return true if the given JSPropertySpec::name or JSFunctionSpec::name value
 * is actually a symbol code and not a string. See JS_SYM_FN.
 */
inline bool PropertySpecNameIsSymbol(const char* name) {
  uintptr_t u = reinterpret_cast<uintptr_t>(name);
  return u != 0 && u - 1 < WellKnownSymbolLimit;
}

JS_PUBLIC_API bool PropertySpecNameEqualsId(const char* name, HandleId id);

/**
 * Create a jsid that does not need to be marked for GC.
 *
 * 'name' is a JSPropertySpec::name or JSFunctionSpec::name value. The
 * resulting jsid, on success, is either an interned string or a well-known
 * symbol; either way it is immune to GC so there is no need to visit *idp
 * during GC marking.
 */
JS_PUBLIC_API bool PropertySpecNameToPermanentId(JSContext* cx,
                                                 const char* name, jsid* idp);

} /* namespace JS */

/************************************************************************/
/*
 * JSON functions
 */
typedef bool (*JSONWriteCallback)(const char16_t* buf, uint32_t len,
                                  void* data);

/**
 * JSON.stringify as specified by ES5.
 */
JS_PUBLIC_API bool JS_Stringify(JSContext* cx, JS::MutableHandleValue value,
                                JS::HandleObject replacer,
                                JS::HandleValue space,
                                JSONWriteCallback callback, void* data);

namespace JS {

/**
 * An API akin to JS_Stringify but with the goal of not having observable
 * side-effects when the stringification is performed.  This means it does not
 * allow a replacer or a custom space, and has the following constraints on its
 * input:
 *
 * 1) The input must be a plain object or array, not an abitrary value.
 * 2) Every value in the graph reached by the algorithm starting with this
 *    object must be one of the following: null, undefined, a string (NOT a
 *    string object!), a boolean, a finite number (i.e. no NaN or Infinity or
 *    -Infinity), a plain object with no accessor properties, or an Array with
 *    no holes.
 *
 * The actual behavior differs from JS_Stringify only in asserting the above and
 * NOT attempting to get the "toJSON" property from things, since that could
 * clearly have side-effects.
 */
JS_PUBLIC_API bool ToJSONMaybeSafely(JSContext* cx, JS::HandleObject input,
                                     JSONWriteCallback callback, void* data);

} /* namespace JS */

/**
 * JSON.parse as specified by ES5.
 */
JS_PUBLIC_API bool JS_ParseJSON(JSContext* cx, const char16_t* chars,
                                uint32_t len, JS::MutableHandleValue vp);

JS_PUBLIC_API bool JS_ParseJSON(JSContext* cx, JS::HandleString str,
                                JS::MutableHandleValue vp);

JS_PUBLIC_API bool JS_ParseJSONWithReviver(JSContext* cx, const char16_t* chars,
                                           uint32_t len,
                                           JS::HandleValue reviver,
                                           JS::MutableHandleValue vp);

JS_PUBLIC_API bool JS_ParseJSONWithReviver(JSContext* cx, JS::HandleString str,
                                           JS::HandleValue reviver,
                                           JS::MutableHandleValue vp);

/************************************************************************/

/**
 * The default locale for the ECMAScript Internationalization API
 * (Intl.Collator, Intl.NumberFormat, Intl.DateTimeFormat).
 * Note that the Internationalization API encourages clients to
 * specify their own locales.
 * The locale string remains owned by the caller.
 */
extern JS_PUBLIC_API bool JS_SetDefaultLocale(JSRuntime* rt,
                                              const char* locale);

/**
 * Look up the default locale for the ECMAScript Internationalization API.
 * NB: The locale information is retrieved from cx's runtime.
 */
extern JS_PUBLIC_API JS::UniqueChars JS_GetDefaultLocale(JSContext* cx);

/**
 * Reset the default locale to OS defaults.
 */
extern JS_PUBLIC_API void JS_ResetDefaultLocale(JSRuntime* rt);

/**
 * Locale specific string conversion and error message callbacks.
 */
struct JSLocaleCallbacks {
  JSLocaleToUpperCase localeToUpperCase;  // not used #if EXPOSE_INTL_API
  JSLocaleToLowerCase localeToLowerCase;  // not used #if EXPOSE_INTL_API
  JSLocaleCompare localeCompare;          // not used #if EXPOSE_INTL_API
  JSLocaleToUnicode localeToUnicode;
};

/**
 * Establish locale callbacks. The pointer must persist as long as the
 * JSContext.  Passing nullptr restores the default behaviour.
 */
extern JS_PUBLIC_API void JS_SetLocaleCallbacks(
    JSRuntime* rt, const JSLocaleCallbacks* callbacks);

/**
 * Return the address of the current locale callbacks struct, which may
 * be nullptr.
 */
extern JS_PUBLIC_API const JSLocaleCallbacks* JS_GetLocaleCallbacks(
    JSRuntime* rt);

/************************************************************************/

/*
 * Error reporting.
 *
 * There are four encoding variants for the error reporting API:
 *   UTF-8
 *     JSAPI's default encoding for error handling.  Use this when the encoding
 *     of the error message, format string, and arguments is UTF-8.
 *   ASCII
 *     Equivalent to UTF-8, but also asserts that the error message, format
 *     string, and arguments are all ASCII.  Because ASCII is a subset of UTF-8,
 *     any use of this encoding variant *could* be replaced with use of the
 *     UTF-8 variant.  This variant exists solely to double-check the
 *     developer's assumption that all these strings truly are ASCII, given that
 *     UTF-8 and ASCII strings regrettably have the same C++ type.
 *   UC = UTF-16
 *     Use this when arguments are UTF-16.  The format string must be UTF-8.
 *   Latin1 (planned to be removed)
 *     In this variant, all strings are interpreted byte-for-byte as the
 *     corresponding Unicode codepoint.  This encoding may *safely* be used on
 *     any null-terminated string, regardless of its encoding.  (You shouldn't
 *     *actually* be uncertain, but in the real world, a string's encoding -- if
 *     promised at all -- may be more...aspirational...than reality.)  This
 *     encoding variant will eventually be removed -- work to convert your uses
 *     to UTF-8 as you're able.
 */

namespace JS {
const uint16_t MaxNumErrorArguments = 10;
};

/**
 * Report an exception represented by the sprintf-like conversion of format
 * and its arguments.
 */
extern JS_PUBLIC_API void JS_ReportErrorASCII(JSContext* cx, const char* format,
                                              ...) MOZ_FORMAT_PRINTF(2, 3);

extern JS_PUBLIC_API void JS_ReportErrorLatin1(JSContext* cx,
                                               const char* format, ...)
    MOZ_FORMAT_PRINTF(2, 3);

extern JS_PUBLIC_API void JS_ReportErrorUTF8(JSContext* cx, const char* format,
                                             ...) MOZ_FORMAT_PRINTF(2, 3);

/*
 * Use an errorNumber to retrieve the format string, args are char*
 */
extern JS_PUBLIC_API void JS_ReportErrorNumberASCII(
    JSContext* cx, JSErrorCallback errorCallback, void* userRef,
    const unsigned errorNumber, ...);

extern JS_PUBLIC_API void JS_ReportErrorNumberASCIIVA(
    JSContext* cx, JSErrorCallback errorCallback, void* userRef,
    const unsigned errorNumber, va_list ap);

extern JS_PUBLIC_API void JS_ReportErrorNumberLatin1(
    JSContext* cx, JSErrorCallback errorCallback, void* userRef,
    const unsigned errorNumber, ...);

#ifdef va_start
extern JS_PUBLIC_API void JS_ReportErrorNumberLatin1VA(
    JSContext* cx, JSErrorCallback errorCallback, void* userRef,
    const unsigned errorNumber, va_list ap);
#endif

extern JS_PUBLIC_API void JS_ReportErrorNumberUTF8(
    JSContext* cx, JSErrorCallback errorCallback, void* userRef,
    const unsigned errorNumber, ...);

#ifdef va_start
extern JS_PUBLIC_API void JS_ReportErrorNumberUTF8VA(
    JSContext* cx, JSErrorCallback errorCallback, void* userRef,
    const unsigned errorNumber, va_list ap);
#endif

/*
 * Use an errorNumber to retrieve the format string, args are char16_t*
 */
extern JS_PUBLIC_API void JS_ReportErrorNumberUC(JSContext* cx,
                                                 JSErrorCallback errorCallback,
                                                 void* userRef,
                                                 const unsigned errorNumber,
                                                 ...);

extern JS_PUBLIC_API void JS_ReportErrorNumberUCArray(
    JSContext* cx, JSErrorCallback errorCallback, void* userRef,
    const unsigned errorNumber, const char16_t** args);

/**
 * As above, but report a warning instead (JSREPORT_IS_WARNING(report.flags)).
 * Return true if there was no error trying to issue the warning, and if the
 * warning was not converted into an error due to the JSOPTION_WERROR option
 * being set, false otherwise.
 */
extern JS_PUBLIC_API bool JS_ReportWarningASCII(JSContext* cx,
                                                const char* format, ...)
    MOZ_FORMAT_PRINTF(2, 3);

extern JS_PUBLIC_API bool JS_ReportWarningLatin1(JSContext* cx,
                                                 const char* format, ...)
    MOZ_FORMAT_PRINTF(2, 3);

extern JS_PUBLIC_API bool JS_ReportWarningUTF8(JSContext* cx,
                                               const char* format, ...)
    MOZ_FORMAT_PRINTF(2, 3);

extern JS_PUBLIC_API bool JS_ReportErrorFlagsAndNumberASCII(
    JSContext* cx, unsigned flags, JSErrorCallback errorCallback, void* userRef,
    const unsigned errorNumber, ...);

extern JS_PUBLIC_API bool JS_ReportErrorFlagsAndNumberLatin1(
    JSContext* cx, unsigned flags, JSErrorCallback errorCallback, void* userRef,
    const unsigned errorNumber, ...);

extern JS_PUBLIC_API bool JS_ReportErrorFlagsAndNumberUTF8(
    JSContext* cx, unsigned flags, JSErrorCallback errorCallback, void* userRef,
    const unsigned errorNumber, ...);

extern JS_PUBLIC_API bool JS_ReportErrorFlagsAndNumberUC(
    JSContext* cx, unsigned flags, JSErrorCallback errorCallback, void* userRef,
    const unsigned errorNumber, ...);

/**
 * Complain when out of memory.
 */
extern JS_PUBLIC_API void JS_ReportOutOfMemory(JSContext* cx);

/**
 * Complain when an allocation size overflows the maximum supported limit.
 */
extern JS_PUBLIC_API void JS_ReportAllocationOverflow(JSContext* cx);

/**
 * Base class that implements parts shared by JSErrorReport and
 * JSErrorNotes::Note.
 */
class JSErrorBase {
  // The (default) error message.
  // If ownsMessage_ is true, the it is freed in destructor.
  JS::ConstUTF8CharsZ message_;

 public:
  JSErrorBase()
      : filename(nullptr),
        lineno(0),
        column(0),
        errorNumber(0),
        ownsMessage_(false) {}

  ~JSErrorBase() { freeMessage(); }

  // Source file name, URL, etc., or null.
  const char* filename;

  // Source line number.
  unsigned lineno;

  // Zero-based column index in line.
  unsigned column;

  // the error number, e.g. see js.msg.
  unsigned errorNumber;

 private:
  bool ownsMessage_ : 1;

 public:
  const JS::ConstUTF8CharsZ message() const { return message_; }

  void initOwnedMessage(const char* messageArg) {
    initBorrowedMessage(messageArg);
    ownsMessage_ = true;
  }
  void initBorrowedMessage(const char* messageArg) {
    MOZ_ASSERT(!message_);
    message_ = JS::ConstUTF8CharsZ(messageArg, strlen(messageArg));
  }

  JSString* newMessageString(JSContext* cx);

 private:
  void freeMessage();
};

/**
 * Notes associated with JSErrorReport.
 */
class JSErrorNotes {
 public:
  class Note : public JSErrorBase {};

 private:
  // Stores pointers to each note.
  js::Vector<js::UniquePtr<Note>, 1, js::SystemAllocPolicy> notes_;

 public:
  JSErrorNotes();
  ~JSErrorNotes();

  // Add an note to the given position.
  bool addNoteASCII(JSContext* cx, const char* filename, unsigned lineno,
                    unsigned column, JSErrorCallback errorCallback,
                    void* userRef, const unsigned errorNumber, ...);
  bool addNoteLatin1(JSContext* cx, const char* filename, unsigned lineno,
                     unsigned column, JSErrorCallback errorCallback,
                     void* userRef, const unsigned errorNumber, ...);
  bool addNoteUTF8(JSContext* cx, const char* filename, unsigned lineno,
                   unsigned column, JSErrorCallback errorCallback,
                   void* userRef, const unsigned errorNumber, ...);

  JS_PUBLIC_API size_t length();

  // Create a deep copy of notes.
  js::UniquePtr<JSErrorNotes> copy(JSContext* cx);

  class iterator
      : public std::iterator<std::input_iterator_tag, js::UniquePtr<Note>> {
    js::UniquePtr<Note>* note_;

   public:
    explicit iterator(js::UniquePtr<Note>* note = nullptr) : note_(note) {}

    bool operator==(iterator other) const { return note_ == other.note_; }
    bool operator!=(iterator other) const { return !(*this == other); }
    iterator& operator++() {
      note_++;
      return *this;
    }
    reference operator*() { return *note_; }
  };
  JS_PUBLIC_API iterator begin();
  JS_PUBLIC_API iterator end();
};

/**
 * Describes a single error or warning that occurs in the execution of script.
 */
class JSErrorReport : public JSErrorBase {
  // Offending source line without final '\n'.
  // If ownsLinebuf_ is true, the buffer is freed in destructor.
  const char16_t* linebuf_;

  // Number of chars in linebuf_. Does not include trailing '\0'.
  size_t linebufLength_;

  // The 0-based offset of error token in linebuf_.
  size_t tokenOffset_;

 public:
  JSErrorReport()
      : linebuf_(nullptr),
        linebufLength_(0),
        tokenOffset_(0),
        notes(nullptr),
        flags(0),
        exnType(0),
        isMuted(false),
        ownsLinebuf_(false) {}

  ~JSErrorReport() { freeLinebuf(); }

  // Associated notes, or nullptr if there's no note.
  js::UniquePtr<JSErrorNotes> notes;

  // error/warning, etc.
  unsigned flags;

  // One of the JSExnType constants.
  int16_t exnType;

  // See the comment in TransitiveCompileOptions.
  bool isMuted : 1;

 private:
  bool ownsLinebuf_ : 1;

 public:
  const char16_t* linebuf() const { return linebuf_; }
  size_t linebufLength() const { return linebufLength_; }
  size_t tokenOffset() const { return tokenOffset_; }
  void initOwnedLinebuf(const char16_t* linebufArg, size_t linebufLengthArg,
                        size_t tokenOffsetArg) {
    initBorrowedLinebuf(linebufArg, linebufLengthArg, tokenOffsetArg);
    ownsLinebuf_ = true;
  }
  void initBorrowedLinebuf(const char16_t* linebufArg, size_t linebufLengthArg,
                           size_t tokenOffsetArg);

 private:
  void freeLinebuf();
};

/*
 * JSErrorReport flag values.  These may be freely composed.
 */
#define JSREPORT_ERROR 0x0     /* pseudo-flag for default case */
#define JSREPORT_WARNING 0x1   /* reported via JS_ReportWarning */
#define JSREPORT_EXCEPTION 0x2 /* exception was thrown */
#define JSREPORT_STRICT 0x4    /* error or warning due to strict option */

#define JSREPORT_USER_1 0x8 /* user-defined flag */

/*
 * If JSREPORT_EXCEPTION is set, then a JavaScript-catchable exception
 * has been thrown for this runtime error, and the host should ignore it.
 * Exception-aware hosts should also check for JS_IsExceptionPending if
 * JS_ExecuteScript returns failure, and signal or propagate the exception, as
 * appropriate.
 */
#define JSREPORT_IS_WARNING(flags) (((flags)&JSREPORT_WARNING) != 0)
#define JSREPORT_IS_EXCEPTION(flags) (((flags)&JSREPORT_EXCEPTION) != 0)
#define JSREPORT_IS_STRICT(flags) (((flags)&JSREPORT_STRICT) != 0)

namespace JS {

using WarningReporter = void (*)(JSContext* cx, JSErrorReport* report);

extern JS_PUBLIC_API WarningReporter
SetWarningReporter(JSContext* cx, WarningReporter reporter);

extern JS_PUBLIC_API WarningReporter GetWarningReporter(JSContext* cx);

extern JS_PUBLIC_API bool CreateError(
    JSContext* cx, JSExnType type, HandleObject stack, HandleString fileName,
    uint32_t lineNumber, uint32_t columnNumber, JSErrorReport* report,
    HandleString message, MutableHandleValue rval);

/************************************************************************/

/*
 * Weak Maps.
 */

extern JS_PUBLIC_API JSObject* NewWeakMapObject(JSContext* cx);

extern JS_PUBLIC_API bool IsWeakMapObject(JSObject* obj);

extern JS_PUBLIC_API bool GetWeakMapEntry(JSContext* cx,
                                          JS::HandleObject mapObj,
                                          JS::HandleObject key,
                                          JS::MutableHandleValue val);

extern JS_PUBLIC_API bool SetWeakMapEntry(JSContext* cx,
                                          JS::HandleObject mapObj,
                                          JS::HandleObject key,
                                          JS::HandleValue val);

/*
 * Map
 */
extern JS_PUBLIC_API JSObject* NewMapObject(JSContext* cx);

extern JS_PUBLIC_API uint32_t MapSize(JSContext* cx, HandleObject obj);

extern JS_PUBLIC_API bool MapGet(JSContext* cx, HandleObject obj,
                                 HandleValue key, MutableHandleValue rval);

extern JS_PUBLIC_API bool MapHas(JSContext* cx, HandleObject obj,
                                 HandleValue key, bool* rval);

extern JS_PUBLIC_API bool MapSet(JSContext* cx, HandleObject obj,
                                 HandleValue key, HandleValue val);

extern JS_PUBLIC_API bool MapDelete(JSContext* cx, HandleObject obj,
                                    HandleValue key, bool* rval);

extern JS_PUBLIC_API bool MapClear(JSContext* cx, HandleObject obj);

extern JS_PUBLIC_API bool MapKeys(JSContext* cx, HandleObject obj,
                                  MutableHandleValue rval);

extern JS_PUBLIC_API bool MapValues(JSContext* cx, HandleObject obj,
                                    MutableHandleValue rval);

extern JS_PUBLIC_API bool MapEntries(JSContext* cx, HandleObject obj,
                                     MutableHandleValue rval);

extern JS_PUBLIC_API bool MapForEach(JSContext* cx, HandleObject obj,
                                     HandleValue callbackFn,
                                     HandleValue thisVal);

/*
 * Set
 */
extern JS_PUBLIC_API JSObject* NewSetObject(JSContext* cx);

extern JS_PUBLIC_API uint32_t SetSize(JSContext* cx, HandleObject obj);

extern JS_PUBLIC_API bool SetHas(JSContext* cx, HandleObject obj,
                                 HandleValue key, bool* rval);

extern JS_PUBLIC_API bool SetDelete(JSContext* cx, HandleObject obj,
                                    HandleValue key, bool* rval);

extern JS_PUBLIC_API bool SetAdd(JSContext* cx, HandleObject obj,
                                 HandleValue key);

extern JS_PUBLIC_API bool SetClear(JSContext* cx, HandleObject obj);

extern JS_PUBLIC_API bool SetKeys(JSContext* cx, HandleObject obj,
                                  MutableHandleValue rval);

extern JS_PUBLIC_API bool SetValues(JSContext* cx, HandleObject obj,
                                    MutableHandleValue rval);

extern JS_PUBLIC_API bool SetEntries(JSContext* cx, HandleObject obj,
                                     MutableHandleValue rval);

extern JS_PUBLIC_API bool SetForEach(JSContext* cx, HandleObject obj,
                                     HandleValue callbackFn,
                                     HandleValue thisVal);

} /* namespace JS */

/*
 * Dates.
 */

extern JS_PUBLIC_API JSObject* JS_NewDateObject(JSContext* cx, int year,
                                                int mon, int mday, int hour,
                                                int min, int sec);

/**
 * Returns true and sets |*isDate| indicating whether |obj| is a Date object or
 * a wrapper around one, otherwise returns false on failure.
 *
 * This method returns true with |*isDate == false| when passed a proxy whose
 * target is a Date, or when passed a revoked proxy.
 */
extern JS_PUBLIC_API bool JS_ObjectIsDate(JSContext* cx, JS::HandleObject obj,
                                          bool* isDate);

/************************************************************************/

/*
 * Regular Expressions.
 */
#define JSREG_FOLD 0x01u      /* fold uppercase to lowercase */
#define JSREG_GLOB 0x02u      /* global exec, creates array of matches */
#define JSREG_MULTILINE 0x04u /* treat ^ and $ as begin and end of line */
#define JSREG_STICKY 0x08u    /* only match starting at lastIndex */
#define JSREG_UNICODE 0x10u   /* unicode */

extern JS_PUBLIC_API JSObject* JS_NewRegExpObject(JSContext* cx,
                                                  const char* bytes,
                                                  size_t length,
                                                  unsigned flags);

extern JS_PUBLIC_API JSObject* JS_NewUCRegExpObject(JSContext* cx,
                                                    const char16_t* chars,
                                                    size_t length,
                                                    unsigned flags);

extern JS_PUBLIC_API bool JS_SetRegExpInput(JSContext* cx, JS::HandleObject obj,
                                            JS::HandleString input);

extern JS_PUBLIC_API bool JS_ClearRegExpStatics(JSContext* cx,
                                                JS::HandleObject obj);

extern JS_PUBLIC_API bool JS_ExecuteRegExp(JSContext* cx, JS::HandleObject obj,
                                           JS::HandleObject reobj,
                                           char16_t* chars, size_t length,
                                           size_t* indexp, bool test,
                                           JS::MutableHandleValue rval);

/* RegExp interface for clients without a global object. */

extern JS_PUBLIC_API bool JS_ExecuteRegExpNoStatics(
    JSContext* cx, JS::HandleObject reobj, char16_t* chars, size_t length,
    size_t* indexp, bool test, JS::MutableHandleValue rval);

/**
 * Returns true and sets |*isRegExp| indicating whether |obj| is a RegExp
 * object or a wrapper around one, otherwise returns false on failure.
 *
 * This method returns true with |*isRegExp == false| when passed a proxy whose
 * target is a RegExp, or when passed a revoked proxy.
 */
extern JS_PUBLIC_API bool JS_ObjectIsRegExp(JSContext* cx, JS::HandleObject obj,
                                            bool* isRegExp);

extern JS_PUBLIC_API unsigned JS_GetRegExpFlags(JSContext* cx,
                                                JS::HandleObject obj);

extern JS_PUBLIC_API JSString* JS_GetRegExpSource(JSContext* cx,
                                                  JS::HandleObject obj);

/************************************************************************/

extern JS_PUBLIC_API bool JS_IsExceptionPending(JSContext* cx);

extern JS_PUBLIC_API bool JS_GetPendingException(JSContext* cx,
                                                 JS::MutableHandleValue vp);

extern JS_PUBLIC_API void JS_SetPendingException(JSContext* cx,
                                                 JS::HandleValue v);

extern JS_PUBLIC_API void JS_ClearPendingException(JSContext* cx);

namespace JS {

/**
 * Save and later restore the current exception state of a given JSContext.
 * This is useful for implementing behavior in C++ that's like try/catch
 * or try/finally in JS.
 *
 * Typical usage:
 *
 *     bool ok = JS::Evaluate(cx, ...);
 *     AutoSaveExceptionState savedExc(cx);
 *     ... cleanup that might re-enter JS ...
 *     return ok;
 */
class JS_PUBLIC_API AutoSaveExceptionState {
 private:
  JSContext* context;
  bool wasPropagatingForcedReturn;
  bool wasOverRecursed;
  bool wasThrowing;
  RootedValue exceptionValue;

 public:
  /*
   * Take a snapshot of cx's current exception state. Then clear any current
   * pending exception in cx.
   */
  explicit AutoSaveExceptionState(JSContext* cx);

  /*
   * If neither drop() nor restore() was called, restore the exception
   * state only if no exception is currently pending on cx.
   */
  ~AutoSaveExceptionState();

  /*
   * Discard any stored exception state.
   * If this is called, the destructor is a no-op.
   */
  void drop() {
    wasPropagatingForcedReturn = false;
    wasOverRecursed = false;
    wasThrowing = false;
    exceptionValue.setUndefined();
  }

  /*
   * Replace cx's exception state with the stored exception state. Then
   * discard the stored exception state. If this is called, the
   * destructor is a no-op.
   */
  void restore();
};

} /* namespace JS */

/* Deprecated API. Use AutoSaveExceptionState instead. */
extern JS_PUBLIC_API JSExceptionState* JS_SaveExceptionState(JSContext* cx);

extern JS_PUBLIC_API void JS_RestoreExceptionState(JSContext* cx,
                                                   JSExceptionState* state);

extern JS_PUBLIC_API void JS_DropExceptionState(JSContext* cx,
                                                JSExceptionState* state);

/**
 * If the given object is an exception object, the exception will have (or be
 * able to lazily create) an error report struct, and this function will return
 * the address of that struct.  Otherwise, it returns nullptr. The lifetime
 * of the error report struct that might be returned is the same as the
 * lifetime of the exception object.
 */
extern JS_PUBLIC_API JSErrorReport* JS_ErrorFromException(JSContext* cx,
                                                          JS::HandleObject obj);

namespace JS {
/**
 * If the given object is an exception object (or an unwrappable
 * cross-compartment wrapper for one), return the stack for that exception, if
 * any.  Will return null if the given object is not an exception object
 * (including if it's null or a security wrapper that can't be unwrapped) or if
 * the exception has no stack.
 */
extern JS_PUBLIC_API JSObject* ExceptionStackOrNull(JS::HandleObject obj);

} /* namespace JS */

/**
 * A JS context always has an "owner thread". The owner thread is set when the
 * context is created (to the current thread) and practically all entry points
 * into the JS engine check that a context (or anything contained in the
 * context: runtime, compartment, object, etc) is only touched by its owner
 * thread. Embeddings may check this invariant outside the JS engine by calling
 * JS_AbortIfWrongThread (which will abort if not on the owner thread, even for
 * non-debug builds).
 */

extern JS_PUBLIC_API void JS_AbortIfWrongThread(JSContext* cx);

/************************************************************************/

/**
 * A constructor can request that the JS engine create a default new 'this'
 * object of the given class, using the callee to determine parentage and
 * [[Prototype]].
 */
extern JS_PUBLIC_API JSObject* JS_NewObjectForConstructor(
    JSContext* cx, const JSClass* clasp, const JS::CallArgs& args);

/************************************************************************/

#ifdef JS_GC_ZEAL
#define JS_DEFAULT_ZEAL_FREQ 100

extern JS_PUBLIC_API void JS_GetGCZealBits(JSContext* cx, uint32_t* zealBits,
                                           uint32_t* frequency,
                                           uint32_t* nextScheduled);

extern JS_PUBLIC_API void JS_SetGCZeal(JSContext* cx, uint8_t zeal,
                                       uint32_t frequency);

extern JS_PUBLIC_API void JS_ScheduleGC(JSContext* cx, uint32_t count);
#endif

extern JS_PUBLIC_API void JS_SetParallelParsingEnabled(JSContext* cx,
                                                       bool enabled);

extern JS_PUBLIC_API void JS_SetOffthreadIonCompilationEnabled(JSContext* cx,
                                                               bool enabled);

//clang-format off
#define JIT_COMPILER_OPTIONS(Register) \
   Register(BASELINE_WARMUP_TRIGGER, "baseline.warmup.trigger") \
   Register(ION_WARMUP_TRIGGER, "ion.warmup.trigger") \
   Register(ION_GVN_ENABLE, "ion.gvn.enable") \
   Register(ION_FORCE_IC, "ion.forceinlineCaches") \
   Register(ION_ENABLE, "ion.enable") \
   Register(ION_INTERRUPT_WITHOUT_SIGNAL, "ion.interrupt-without-signals") \
   Register(ION_CHECK_RANGE_ANALYSIS, "ion.check-range-analysis") \
   Register(BASELINE_ENABLE, "baseline.enable") \
   Register(OFFTHREAD_COMPILATION_ENABLE, "offthread-compilation.enable") \
   Register(FULL_DEBUG_CHECKS, "jit.full-debug-checks") \
   Register(JUMP_THRESHOLD, "jump-threshold") \
   Register(UNBOXED_OBJECTS, "unboxed_objects") \
   Register(SIMULATOR_ALWAYS_INTERRUPT, "simulator.always-interrupt") \
   Register(SPECTRE_INDEX_MASKING, "spectre.index-masking") \
   Register(SPECTRE_OBJECT_MITIGATIONS_BARRIERS, "spectre.object-mitigations.barriers") \
   Register(SPECTRE_OBJECT_MITIGATIONS_MISC, "spectre.object-mitigations.misc") \
   Register(SPECTRE_STRING_MITIGATIONS, "spectre.string-mitigations") \
   Register(SPECTRE_VALUE_MASKING, "spectre.value-masking") \
   Register(SPECTRE_JIT_TO_CXX_CALLS, "spectre.jit-to-C++-calls") \
   Register(ASMJS_ATOMICS_ENABLE, "asmjs.atomics.enable") \
   Register(WASM_FOLD_OFFSETS, "wasm.fold-offsets") \
   Register(WASM_DELAY_TIER2, "wasm.delay-tier2")
//clang-format on

typedef enum JSJitCompilerOption {
#define JIT_COMPILER_DECLARE(key, str) JSJITCOMPILER_##key,

  JIT_COMPILER_OPTIONS(JIT_COMPILER_DECLARE)
#undef JIT_COMPILER_DECLARE

      JSJITCOMPILER_NOT_AN_OPTION
} JSJitCompilerOption;

extern JS_PUBLIC_API void JS_SetGlobalJitCompilerOption(JSContext* cx,
                                                        JSJitCompilerOption opt,
                                                        uint32_t value);
extern JS_PUBLIC_API bool JS_GetGlobalJitCompilerOption(JSContext* cx,
                                                        JSJitCompilerOption opt,
                                                        uint32_t* valueOut);

/**
 * Convert a uint32_t index into a jsid.
 */
extern JS_PUBLIC_API bool JS_IndexToId(JSContext* cx, uint32_t index,
                                       JS::MutableHandleId);

/**
 * Convert chars into a jsid.
 *
 * |chars| may not be an index.
 */
extern JS_PUBLIC_API bool JS_CharsToId(JSContext* cx, JS::TwoByteChars chars,
                                       JS::MutableHandleId);

/**
 *  Test if the given string is a valid ECMAScript identifier
 */
extern JS_PUBLIC_API bool JS_IsIdentifier(JSContext* cx, JS::HandleString str,
                                          bool* isIdentifier);

/**
 * Test whether the given chars + length are a valid ECMAScript identifier.
 * This version is infallible, so just returns whether the chars are an
 * identifier.
 */
extern JS_PUBLIC_API bool JS_IsIdentifier(const char16_t* chars, size_t length);

namespace js {
class ScriptSource;
}  // namespace js

namespace JS {

class MOZ_RAII JS_PUBLIC_API AutoFilename {
 private:
  js::ScriptSource* ss_;
  mozilla::Variant<const char*, UniqueChars> filename_;

  AutoFilename(const AutoFilename&) = delete;
  AutoFilename& operator=(const AutoFilename&) = delete;

 public:
  AutoFilename()
      : ss_(nullptr), filename_(mozilla::AsVariant<const char*>(nullptr)) {}

  ~AutoFilename() { reset(); }

  void reset();

  void setOwned(UniqueChars&& filename);
  void setUnowned(const char* filename);
  void setScriptSource(js::ScriptSource* ss);

  const char* get() const;
};

/**
 * Return the current filename, line number and column number of the most
 * currently running frame. Returns true if a scripted frame was found, false
 * otherwise.
 *
 * If a the embedding has hidden the scripted caller for the topmost activation
 * record, this will also return false.
 */
extern JS_PUBLIC_API bool DescribeScriptedCaller(
    JSContext* cx, AutoFilename* filename = nullptr, unsigned* lineno = nullptr,
    unsigned* column = nullptr);

extern JS_PUBLIC_API JSObject* GetScriptedCallerGlobal(JSContext* cx);

/**
 * Informs the JS engine that the scripted caller should be hidden. This can be
 * used by the embedding to maintain an override of the scripted caller in its
 * calculations, by hiding the scripted caller in the JS engine and pushing data
 * onto a separate stack, which it inspects when DescribeScriptedCaller returns
 * null.
 *
 * We maintain a counter on each activation record. Add() increments the counter
 * of the topmost activation, and Remove() decrements it. The count may never
 * drop below zero, and must always be exactly zero when the activation is
 * popped from the stack.
 */
extern JS_PUBLIC_API void HideScriptedCaller(JSContext* cx);

extern JS_PUBLIC_API void UnhideScriptedCaller(JSContext* cx);

class MOZ_RAII AutoHideScriptedCaller {
 public:
  explicit AutoHideScriptedCaller(JSContext* cx MOZ_GUARD_OBJECT_NOTIFIER_PARAM)
      : mContext(cx) {
    MOZ_GUARD_OBJECT_NOTIFIER_INIT;
    HideScriptedCaller(mContext);
  }
  ~AutoHideScriptedCaller() { UnhideScriptedCaller(mContext); }

 protected:
  JSContext* mContext;
  MOZ_DECL_USE_GUARD_OBJECT_NOTIFIER
};

/*
 * Encode/Decode interpreted scripts and functions to/from memory.
 */

typedef mozilla::Vector<uint8_t> TranscodeBuffer;
typedef mozilla::Range<uint8_t> TranscodeRange;

struct TranscodeSource {
  TranscodeSource(const TranscodeRange& range_, const char* file, uint32_t line)
      : range(range_), filename(file), lineno(line) {}

  const TranscodeRange range;
  const char* filename;
  const uint32_t lineno;
};

typedef mozilla::Vector<JS::TranscodeSource> TranscodeSources;

enum TranscodeResult {
  // Successful encoding / decoding.
  TranscodeResult_Ok = 0,

  // A warning message, is set to the message out-param.
  TranscodeResult_Failure = 0x100,
  TranscodeResult_Failure_BadBuildId = TranscodeResult_Failure | 0x1,
  TranscodeResult_Failure_RunOnceNotSupported = TranscodeResult_Failure | 0x2,
  TranscodeResult_Failure_AsmJSNotSupported = TranscodeResult_Failure | 0x3,
  TranscodeResult_Failure_BadDecode = TranscodeResult_Failure | 0x4,
  TranscodeResult_Failure_WrongCompileOption = TranscodeResult_Failure | 0x5,
  TranscodeResult_Failure_NotInterpretedFun = TranscodeResult_Failure | 0x6,

  // There is a pending exception on the context.
  TranscodeResult_Throw = 0x200
};

extern JS_PUBLIC_API TranscodeResult EncodeScript(JSContext* cx,
                                                  TranscodeBuffer& buffer,
                                                  JS::HandleScript script);

extern JS_PUBLIC_API TranscodeResult EncodeInterpretedFunction(
    JSContext* cx, TranscodeBuffer& buffer, JS::HandleObject funobj);

extern JS_PUBLIC_API TranscodeResult
DecodeScript(JSContext* cx, TranscodeBuffer& buffer,
             JS::MutableHandleScript scriptp, size_t cursorIndex = 0);

extern JS_PUBLIC_API TranscodeResult
DecodeScript(JSContext* cx, const TranscodeRange& range,
             JS::MutableHandleScript scriptp);

extern JS_PUBLIC_API TranscodeResult DecodeInterpretedFunction(
    JSContext* cx, TranscodeBuffer& buffer, JS::MutableHandleFunction funp,
    size_t cursorIndex = 0);

// Register an encoder on the given script source, such that all functions can
// be encoded as they are parsed. This strategy is used to avoid blocking the
// active thread in a non-interruptible way.
//
// The |script| argument of |StartIncrementalEncoding| and
// |FinishIncrementalEncoding| should be the top-level script returned either as
// an out-param of any of the |Compile| functions, or the result of
// |FinishOffThreadScript|.
//
// The |buffer| argument of |FinishIncrementalEncoding| is used for appending
// the encoded bytecode into the buffer. If any of these functions failed, the
// content of |buffer| would be undefined.
extern JS_PUBLIC_API bool StartIncrementalEncoding(JSContext* cx,
                                                   JS::HandleScript script);

extern JS_PUBLIC_API bool FinishIncrementalEncoding(JSContext* cx,
                                                    JS::HandleScript script,
                                                    TranscodeBuffer& buffer);

} /* namespace JS */

namespace js {

enum class StackFormat { SpiderMonkey, V8, Default };

/*
 * Sets the format used for stringifying Error stacks.
 *
 * The default format is StackFormat::SpiderMonkey.  Use StackFormat::V8
 * in order to emulate V8's stack formatting.  StackFormat::Default can't be
 * used here.
 */
extern JS_PUBLIC_API void SetStackFormat(JSContext* cx, StackFormat format);

extern JS_PUBLIC_API StackFormat GetStackFormat(JSContext* cx);

}  // namespace js

namespace JS {

/*
 * This callback represents a request by the JS engine to open for reading the
 * existing cache entry for the given global and char range that may contain a
 * module. If a cache entry exists, the callback shall return 'true' and return
 * the size, base address and an opaque file handle as outparams. If the
 * callback returns 'true', the JS engine guarantees a call to
 * CloseAsmJSCacheEntryForReadOp, passing the same base address, size and
 * handle.
 */
typedef bool (*OpenAsmJSCacheEntryForReadOp)(
    HandleObject global, const char16_t* begin, const char16_t* limit,
    size_t* size, const uint8_t** memory, intptr_t* handle);
typedef void (*CloseAsmJSCacheEntryForReadOp)(size_t size,
                                              const uint8_t* memory,
                                              intptr_t handle);

/** The list of reasons why an asm.js module may not be stored in the cache. */
enum AsmJSCacheResult {
  AsmJSCache_Success,
  AsmJSCache_MIN = AsmJSCache_Success,
  AsmJSCache_ModuleTooSmall,
  AsmJSCache_SynchronousScript,
  AsmJSCache_QuotaExceeded,
  AsmJSCache_StorageInitFailure,
  AsmJSCache_Disabled_Internal,
  AsmJSCache_Disabled_ShellFlags,
  AsmJSCache_Disabled_JitInspector,
  AsmJSCache_InternalError,
  AsmJSCache_Disabled_PrivateBrowsing,
  AsmJSCache_LIMIT
};

/*
 * This callback represents a request by the JS engine to open for writing a
 * cache entry of the given size for the given global and char range containing
 * the just-compiled module. If cache entry space is available, the callback
 * shall return 'true' and return the base address and an opaque file handle as
 * outparams. If the callback returns 'true', the JS engine guarantees a call
 * to CloseAsmJSCacheEntryForWriteOp passing the same base address, size and
 * handle.
 */
typedef AsmJSCacheResult (*OpenAsmJSCacheEntryForWriteOp)(
    HandleObject global, const char16_t* begin, const char16_t* end,
    size_t size, uint8_t** memory, intptr_t* handle);
typedef void (*CloseAsmJSCacheEntryForWriteOp)(size_t size, uint8_t* memory,
                                               intptr_t handle);

struct AsmJSCacheOps {
  OpenAsmJSCacheEntryForReadOp openEntryForRead;
  CloseAsmJSCacheEntryForReadOp closeEntryForRead;
  OpenAsmJSCacheEntryForWriteOp openEntryForWrite;
  CloseAsmJSCacheEntryForWriteOp closeEntryForWrite;
};

extern JS_PUBLIC_API void SetAsmJSCacheOps(JSContext* cx,
                                           const AsmJSCacheOps* callbacks);

/**
 * Return the buildId (represented as a sequence of characters) associated with
 * the currently-executing build. If the JS engine is embedded such that a
 * single cache entry can be observed by different compiled versions of the JS
 * engine, it is critical that the buildId shall change for each new build of
 * the JS engine.
 */
typedef js::Vector<char, 0, js::SystemAllocPolicy> BuildIdCharVector;

typedef bool (*BuildIdOp)(BuildIdCharVector* buildId);

extern JS_PUBLIC_API void SetBuildIdOp(JSContext* cx, BuildIdOp buildIdOp);

/**
 * The WasmModule interface allows the embedding to hold a reference to the
 * underying C++ implementation of a JS WebAssembly.Module object for purposes
 * of efficient postMessage() and (de)serialization from a random thread.
 *
 * For postMessage() sharing:
 *
 * - GetWasmModule() is called when making a structured clone of payload
 * containing a WebAssembly.Module object. The structured clone buffer holds a
 * refcount of the JS::WasmModule until createObject() is called in the target
 * agent's JSContext. The new WebAssembly.Module object continues to hold the
 * JS::WasmModule and thus the final reference of a JS::WasmModule may be
 * dropped from any thread and so the virtual destructor (and all internal
 * methods of the C++ module) must be thread-safe.
 *
 * For (de)serialization:
 *
 * - Serialization starts when WebAssembly.Module is passed to the
 * structured-clone algorithm. JS::GetWasmModule is called on the JSRuntime
 * thread that initiated the structured clone to get the JS::WasmModule.
 * This interface is then taken to a background thread where the bytecode and
 * compiled code are written into separate files: a bytecode file that always
 * allows successful deserialization and a compiled-code file keyed on cpu- and
 * build-id that may become invalid if either of these change between
 * serialization and deserialization. Due to tiering, the serialization must
 * asynchronously wait for compilation to complete before requesting the
 * module's compiled code. After serialization, a reference is dropped from a
 * separate thread so the virtual destructor must be thread-safe.
 *
 * - Deserialization starts when the structured clone algorithm encounters a
 * serialized WebAssembly.Module. On a background thread, the compiled-code file
 * is opened and CompiledWasmModuleAssumptionsMatch is called to see if it is
 * still valid (as described above). DeserializeWasmModule is then called to
 * construct a JS::WasmModule (also on the background thread), passing the
 * bytecode file descriptor and, if valid, the compiled-code file descriptor.
 * The JS::WasmObject is then transported to a JSContext thread and the wrapping
 * WebAssembly.Module object is created by calling createObject().
 */

class WasmModuleListener {
 protected:
  virtual ~WasmModuleListener() {}

 public:
  // These method signatures are chosen to exactly match nsISupports so that a
  // plain nsISupports-implementing class can trivially implement this
  // interface too. We can't simply #include "nsISupports.h" so we use MFBT
  // equivalents for all the platform-dependent types.
  virtual MozExternalRefCountType MOZ_XPCOM_ABI AddRef() = 0;
  virtual MozExternalRefCountType MOZ_XPCOM_ABI Release() = 0;

  virtual void onCompilationComplete() = 0;
};

struct WasmModule : js::AtomicRefCounted<WasmModule> {
  virtual ~WasmModule() {}

  virtual size_t bytecodeSerializedSize() const = 0;
  virtual void bytecodeSerialize(uint8_t* bytecodeBegin,
                                 size_t bytecodeSize) const = 0;

  // Compilation must complete before the serialized code is requested. If
  // compilation is not complete, the embedding must wait until notified by
  // implementing WasmModuleListener. SpiderMonkey will hold a RefPtr to
  // 'listener' until onCompilationComplete() is called.
  virtual bool compilationComplete() const = 0;
  virtual bool notifyWhenCompilationComplete(WasmModuleListener* listener) = 0;
  virtual size_t compiledSerializedSize() const = 0;
  virtual void compiledSerialize(uint8_t* compiledBegin,
                                 size_t compiledSize) const = 0;

  virtual JSObject* createObject(JSContext* cx) = 0;
};

extern JS_PUBLIC_API bool IsWasmModuleObject(HandleObject obj);

extern JS_PUBLIC_API RefPtr<WasmModule> GetWasmModule(HandleObject obj);

extern JS_PUBLIC_API bool CompiledWasmModuleAssumptionsMatch(
    PRFileDesc* compiled, BuildIdCharVector&& buildId);

extern JS_PUBLIC_API RefPtr<WasmModule> DeserializeWasmModule(
    PRFileDesc* bytecode, PRFileDesc* maybeCompiled,
    BuildIdCharVector&& buildId, JS::UniqueChars filename, unsigned line,
    unsigned column);

/**
 * Convenience class for imitating a JS level for-of loop. Typical usage:
 *
 *     ForOfIterator it(cx);
 *     if (!it.init(iterable))
 *       return false;
 *     RootedValue val(cx);
 *     while (true) {
 *       bool done;
 *       if (!it.next(&val, &done))
 *         return false;
 *       if (done)
 *         break;
 *       if (!DoStuff(cx, val))
 *         return false;
 *     }
 */
class MOZ_STACK_CLASS JS_PUBLIC_API ForOfIterator {
 protected:
  JSContext* cx_;
  /*
   * Use the ForOfPIC on the global object (see vm/GlobalObject.h) to try
   * to optimize iteration across arrays.
   *
   *  Case 1: Regular Iteration
   *      iterator - pointer to the iterator object.
   *      nextMethod - value of |iterator|.next.
   *      index - fixed to NOT_ARRAY (== UINT32_MAX)
   *
   *  Case 2: Optimized Array Iteration
   *      iterator - pointer to the array object.
   *      nextMethod - the undefined value.
   *      index - current position in array.
   *
   * The cases are distinguished by whether or not |index| is equal to
   * NOT_ARRAY.
   */
  JS::RootedObject iterator;
  JS::RootedValue nextMethod;
  uint32_t index;

  static const uint32_t NOT_ARRAY = UINT32_MAX;

  ForOfIterator(const ForOfIterator&) = delete;
  ForOfIterator& operator=(const ForOfIterator&) = delete;

 public:
  explicit ForOfIterator(JSContext* cx)
      : cx_(cx), iterator(cx_), nextMethod(cx), index(NOT_ARRAY) {}

  enum NonIterableBehavior { ThrowOnNonIterable, AllowNonIterable };

  /**
   * Initialize the iterator.  If AllowNonIterable is passed then if getting
   * the @@iterator property from iterable returns undefined init() will just
   * return true instead of throwing.  Callers must then check
   * valueIsIterable() before continuing with the iteration.
   */
  bool init(JS::HandleValue iterable,
            NonIterableBehavior nonIterableBehavior = ThrowOnNonIterable);

  /**
   * Get the next value from the iterator.  If false *done is true
   * after this call, do not examine val.
   */
  bool next(JS::MutableHandleValue val, bool* done);

  /**
   * Close the iterator.
   * For the case that completion type is throw.
   */
  void closeThrow();

  /**
   * If initialized with throwOnNonCallable = false, check whether
   * the value is iterable.
   */
  bool valueIsIterable() const { return iterator; }

 private:
  inline bool nextFromOptimizedArray(MutableHandleValue val, bool* done);
};

/**
 * If a large allocation fails when calling pod_{calloc,realloc}CanGC, the JS
 * engine may call the large-allocation-failure callback, if set, to allow the
 * embedding to flush caches, possibly perform shrinking GCs, etc. to make some
 * room. The allocation will then be retried (and may still fail.) This callback
 * can be called on any thread and must be set at most once in a process.
 */

typedef void (*LargeAllocationFailureCallback)();

extern JS_PUBLIC_API void SetProcessLargeAllocationFailureCallback(
    LargeAllocationFailureCallback afc);

/**
 * Unlike the error reporter, which is only called if the exception for an OOM
 * bubbles up and is not caught, the OutOfMemoryCallback is called immediately
 * at the OOM site to allow the embedding to capture the current state of heap
 * allocation before anything is freed. If the large-allocation-failure callback
 * is called at all (not all allocation sites call the large-allocation-failure
 * callback on failure), it is called before the out-of-memory callback; the
 * out-of-memory callback is only called if the allocation still fails after the
 * large-allocation-failure callback has returned.
 */

typedef void (*OutOfMemoryCallback)(JSContext* cx, void* data);

extern JS_PUBLIC_API void SetOutOfMemoryCallback(JSContext* cx,
                                                 OutOfMemoryCallback cb,
                                                 void* data);

/**
 * Capture all frames.
 */
struct AllFrames {};

/**
 * Capture at most this many frames.
 */
struct MaxFrames {
  uint32_t maxFrames;

  explicit MaxFrames(uint32_t max) : maxFrames(max) { MOZ_ASSERT(max > 0); }
};

/**
 * Capture the first frame with the given principals. By default, do not
 * consider self-hosted frames with the given principals as satisfying the stack
 * capture.
 */
struct JS_PUBLIC_API FirstSubsumedFrame {
  JSContext* cx;
  JSPrincipals* principals;
  bool ignoreSelfHosted;

  /**
   * Use the cx's current compartment's principals.
   */
  explicit FirstSubsumedFrame(JSContext* cx,
                              bool ignoreSelfHostedFrames = true);

  explicit FirstSubsumedFrame(JSContext* ctx, JSPrincipals* p,
                              bool ignoreSelfHostedFrames = true)
      : cx(ctx), principals(p), ignoreSelfHosted(ignoreSelfHostedFrames) {
    if (principals) JS_HoldPrincipals(principals);
  }

  // No copying because we want to avoid holding and dropping principals
  // unnecessarily.
  FirstSubsumedFrame(const FirstSubsumedFrame&) = delete;
  FirstSubsumedFrame& operator=(const FirstSubsumedFrame&) = delete;

  FirstSubsumedFrame(FirstSubsumedFrame&& rhs)
      : principals(rhs.principals), ignoreSelfHosted(rhs.ignoreSelfHosted) {
    MOZ_ASSERT(this != &rhs, "self move disallowed");
    rhs.principals = nullptr;
  }

  FirstSubsumedFrame& operator=(FirstSubsumedFrame&& rhs) {
    new (this) FirstSubsumedFrame(mozilla::Move(rhs));
    return *this;
  }

  ~FirstSubsumedFrame() {
    if (principals) JS_DropPrincipals(cx, principals);
  }
};

using StackCapture = mozilla::Variant<AllFrames, MaxFrames, FirstSubsumedFrame>;

/**
 * Capture the current call stack as a chain of SavedFrame JSObjects, and set
 * |stackp| to the SavedFrame for the youngest stack frame, or nullptr if there
 * are no JS frames on the stack.
 *
 * The |capture| parameter describes the portion of the JS stack to capture:
 *
 *   * |JS::AllFrames|: Capture all frames on the stack.
 *
 *   * |JS::MaxFrames|: Capture no more than |JS::MaxFrames::maxFrames| from the
 *      stack.
 *
 *   * |JS::FirstSubsumedFrame|: Capture the first frame whose principals are
 *     subsumed by |JS::FirstSubsumedFrame::principals|. By default, do not
 *     consider self-hosted frames; this can be controlled via the
 *     |JS::FirstSubsumedFrame::ignoreSelfHosted| flag. Do not capture any async
 *     stack.
 */
extern JS_PUBLIC_API bool CaptureCurrentStack(
    JSContext* cx, MutableHandleObject stackp,
    StackCapture&& capture = StackCapture(AllFrames()));

/*
 * This is a utility function for preparing an async stack to be used
 * by some other object.  This may be used when you need to treat a
 * given stack trace as an async parent.  If you just need to capture
 * the current stack, async parents and all, use CaptureCurrentStack
 * instead.
 *
 * Here |asyncStack| is the async stack to prepare.  It is copied into
 * |cx|'s current compartment, and the newest frame is given
 * |asyncCause| as its asynchronous cause.  If |maxFrameCount| is
 * |Some(n)|, capture at most the youngest |n| frames.  The
 * new stack object is written to |stackp|.  Returns true on success,
 * or sets an exception and returns |false| on error.
 */
extern JS_PUBLIC_API bool CopyAsyncStack(
    JSContext* cx, HandleObject asyncStack, HandleString asyncCause,
    MutableHandleObject stackp, const mozilla::Maybe<size_t>& maxFrameCount);

/*
 * Accessors for working with SavedFrame JSObjects
 *
 * Each of these functions assert that if their `HandleObject savedFrame`
 * argument is non-null, its JSClass is the SavedFrame class (or it is a
 * cross-compartment or Xray wrapper around an object with the SavedFrame class)
 * and the object is not the SavedFrame.prototype object.
 *
 * Each of these functions will find the first SavedFrame object in the chain
 * whose underlying stack frame principals are subsumed by the cx's current
 * compartment's principals, and operate on that SavedFrame object. This
 * prevents leaking information about privileged frames to un-privileged
 * callers. As a result, the SavedFrame in parameters do _NOT_ need to be in the
 * same compartment as the cx, and the various out parameters are _NOT_
 * guaranteed to be in the same compartment as cx.
 *
 * You may consider or skip over self-hosted frames by passing
 * `SavedFrameSelfHosted::Include` or `SavedFrameSelfHosted::Exclude`
 * respectively.
 *
 * Additionally, it may be the case that there is no such SavedFrame object
 * whose captured frame's principals are subsumed by the caller's compartment's
 * principals! If the `HandleObject savedFrame` argument is null, or the
 * caller's principals do not subsume any of the chained SavedFrame object's
 * principals, `SavedFrameResult::AccessDenied` is returned and a (hopefully)
 * sane default value is chosen for the out param.
 *
 * See also `js/src/doc/SavedFrame/SavedFrame.md`.
 */

enum class SavedFrameResult { Ok, AccessDenied };

enum class SavedFrameSelfHosted { Include, Exclude };

/**
 * Given a SavedFrame JSObject, get its source property. Defaults to the empty
 * string.
 */
extern JS_PUBLIC_API SavedFrameResult GetSavedFrameSource(
    JSContext* cx, HandleObject savedFrame, MutableHandleString sourcep,
    SavedFrameSelfHosted selfHosted = SavedFrameSelfHosted::Include);

/**
 * Given a SavedFrame JSObject, get its line property. Defaults to 0.
 */
extern JS_PUBLIC_API SavedFrameResult GetSavedFrameLine(
    JSContext* cx, HandleObject savedFrame, uint32_t* linep,
    SavedFrameSelfHosted selfHosted = SavedFrameSelfHosted::Include);

/**
 * Given a SavedFrame JSObject, get its column property. Defaults to 0.
 */
extern JS_PUBLIC_API SavedFrameResult GetSavedFrameColumn(
    JSContext* cx, HandleObject savedFrame, uint32_t* columnp,
    SavedFrameSelfHosted selfHosted = SavedFrameSelfHosted::Include);

/**
 * Given a SavedFrame JSObject, get its functionDisplayName string, or nullptr
 * if SpiderMonkey was unable to infer a name for the captured frame's
 * function. Defaults to nullptr.
 */
extern JS_PUBLIC_API SavedFrameResult GetSavedFrameFunctionDisplayName(
    JSContext* cx, HandleObject savedFrame, MutableHandleString namep,
    SavedFrameSelfHosted selfHosted = SavedFrameSelfHosted::Include);

/**
 * Given a SavedFrame JSObject, get its asyncCause string. Defaults to nullptr.
 */
extern JS_PUBLIC_API SavedFrameResult GetSavedFrameAsyncCause(
    JSContext* cx, HandleObject savedFrame, MutableHandleString asyncCausep,
    SavedFrameSelfHosted selfHosted = SavedFrameSelfHosted::Include);

/**
 * Given a SavedFrame JSObject, get its asyncParent SavedFrame object or nullptr
 * if there is no asyncParent. The `asyncParentp` out parameter is _NOT_
 * guaranteed to be in the cx's compartment. Defaults to nullptr.
 */
extern JS_PUBLIC_API SavedFrameResult GetSavedFrameAsyncParent(
    JSContext* cx, HandleObject savedFrame, MutableHandleObject asyncParentp,
    SavedFrameSelfHosted selfHosted = SavedFrameSelfHosted::Include);

/**
 * Given a SavedFrame JSObject, get its parent SavedFrame object or nullptr if
 * it is the oldest frame in the stack. The `parentp` out parameter is _NOT_
 * guaranteed to be in the cx's compartment. Defaults to nullptr.
 */
extern JS_PUBLIC_API SavedFrameResult GetSavedFrameParent(
    JSContext* cx, HandleObject savedFrame, MutableHandleObject parentp,
    SavedFrameSelfHosted selfHosted = SavedFrameSelfHosted::Include);

/**
 * Given a SavedFrame JSObject stack, stringify it in the same format as
 * Error.prototype.stack. The stringified stack out parameter is placed in the
 * cx's compartment. Defaults to the empty string.
 *
 * The same notes above about SavedFrame accessors applies here as well: cx
 * doesn't need to be in stack's compartment, and stack can be null, a
 * SavedFrame object, or a wrapper (CCW or Xray) around a SavedFrame object.
 *
 * Optional indent parameter specifies the number of white spaces to indent
 * each line.
 */
extern JS_PUBLIC_API bool BuildStackString(
    JSContext* cx, HandleObject stack, MutableHandleString stringp,
    size_t indent = 0, js::StackFormat stackFormat = js::StackFormat::Default);

/**
 * Return true iff the given object is either a SavedFrame object or wrapper
 * around a SavedFrame object, and it is not the SavedFrame.prototype object.
 */
extern JS_PUBLIC_API bool IsSavedFrame(JSObject* obj);

} /* namespace JS */

/* Stopwatch-based performance monitoring. */

namespace js {

class AutoStopwatch;

/**
 * Abstract base class for a representation of the performance of a
 * component. Embeddings interested in performance monitoring should
 * provide a concrete implementation of this class, as well as the
 * relevant callbacks (see below).
 */
struct JS_PUBLIC_API PerformanceGroup {
  PerformanceGroup();

  // The current iteration of the event loop.
  uint64_t iteration() const;

  // `true` if an instance of `AutoStopwatch` is already monitoring
  // the performance of this performance group for this iteration
  // of the event loop, `false` otherwise.
  bool isAcquired(uint64_t it) const;

  // `true` if a specific instance of `AutoStopwatch` is already monitoring
  // the performance of this performance group for this iteration
  // of the event loop, `false` otherwise.
  bool isAcquired(uint64_t it, const AutoStopwatch* owner) const;

  // Mark that an instance of `AutoStopwatch` is monitoring
  // the performance of this group for a given iteration.
  void acquire(uint64_t it, const AutoStopwatch* owner);

  // Mark that no `AutoStopwatch` is monitoring the
  // performance of this group for the iteration.
  void release(uint64_t it, const AutoStopwatch* owner);

  // The number of cycles spent in this group during this iteration
  // of the event loop. Note that cycles are not a reliable measure,
  // especially over short intervals. See Stopwatch.* for a more
  // complete discussion on the imprecision of cycle measurement.
  uint64_t recentCycles(uint64_t iteration) const;
  void addRecentCycles(uint64_t iteration, uint64_t cycles);

  // The number of times this group has been activated during this
  // iteration of the event loop.
  uint64_t recentTicks(uint64_t iteration) const;
  void addRecentTicks(uint64_t iteration, uint64_t ticks);

  // The number of microseconds spent doing CPOW during this
  // iteration of the event loop.
  uint64_t recentCPOW(uint64_t iteration) const;
  void addRecentCPOW(uint64_t iteration, uint64_t CPOW);

  // Get rid of any data that pretends to be recent.
  void resetRecentData();

  // `true` if new measures should be added to this group, `false`
  // otherwise.
  bool isActive() const;
  void setIsActive(bool);

  // `true` if this group has been used in the current iteration,
  // `false` otherwise.
  bool isUsedInThisIteration() const;
  void setIsUsedInThisIteration(bool);

 protected:
  // An implementation of `delete` for this object. Must be provided
  // by the embedding.
  virtual void Delete() = 0;

 private:
  // The number of cycles spent in this group during this iteration
  // of the event loop. Note that cycles are not a reliable measure,
  // especially over short intervals. See Runtime.cpp for a more
  // complete discussion on the imprecision of cycle measurement.
  uint64_t recentCycles_;

  // The number of times this group has been activated during this
  // iteration of the event loop.
  uint64_t recentTicks_;

  // The number of microseconds spent doing CPOW during this
  // iteration of the event loop.
  uint64_t recentCPOW_;

  // The current iteration of the event loop. If necessary,
  // may safely overflow.
  uint64_t iteration_;

  // `true` if new measures should be added to this group, `false`
  // otherwise.
  bool isActive_;

  // `true` if this group has been used in the current iteration,
  // `false` otherwise.
  bool isUsedInThisIteration_;

  // The stopwatch currently monitoring the group,
  // or `nullptr` if none. Used ony for comparison.
  const AutoStopwatch* owner_;

 public:
  // Compatibility with RefPtr<>
  void AddRef();
  void Release();
  uint64_t refCount_;
};

using PerformanceGroupVector =
    mozilla::Vector<RefPtr<js::PerformanceGroup>, 8, SystemAllocPolicy>;

/**
 * Commit any Performance Monitoring data.
 *
 * Until `FlushMonitoring` has been called, all PerformanceMonitoring data is
 * invisible to the outside world and can cancelled with a call to
 * `ResetMonitoring`.
 */
extern JS_PUBLIC_API bool FlushPerformanceMonitoring(JSContext*);

/**
 * Cancel any measurement that hasn't been committed.
 */
extern JS_PUBLIC_API void ResetPerformanceMonitoring(JSContext*);

/**
 * Cleanup any memory used by performance monitoring.
 */
extern JS_PUBLIC_API void DisposePerformanceMonitoring(JSContext*);

/**
 * Turn on/off stopwatch-based CPU monitoring.
 *
 * `SetStopwatchIsMonitoringCPOW` or `SetStopwatchIsMonitoringJank`
 * may return `false` if monitoring could not be activated, which may
 * happen if we are out of memory.
 */
extern JS_PUBLIC_API bool SetStopwatchIsMonitoringCPOW(JSContext*, bool);
extern JS_PUBLIC_API bool GetStopwatchIsMonitoringCPOW(JSContext*);
extern JS_PUBLIC_API bool SetStopwatchIsMonitoringJank(JSContext*, bool);
extern JS_PUBLIC_API bool GetStopwatchIsMonitoringJank(JSContext*);

// Extract the CPU rescheduling data.
extern JS_PUBLIC_API void GetPerfMonitoringTestCpuRescheduling(JSContext*,
                                                               uint64_t* stayed,
                                                               uint64_t* moved);

/**
 * Add a number of microseconds to the time spent waiting on CPOWs
 * since process start.
 */
extern JS_PUBLIC_API void AddCPOWPerformanceDelta(JSContext*, uint64_t delta);

typedef bool (*StopwatchStartCallback)(uint64_t, void*);
extern JS_PUBLIC_API bool SetStopwatchStartCallback(JSContext*,
                                                    StopwatchStartCallback,
                                                    void*);

typedef bool (*StopwatchCommitCallback)(uint64_t, PerformanceGroupVector&,
                                        void*);
extern JS_PUBLIC_API bool SetStopwatchCommitCallback(JSContext*,
                                                     StopwatchCommitCallback,
                                                     void*);

typedef bool (*GetGroupsCallback)(JSContext*, PerformanceGroupVector&, void*);
extern JS_PUBLIC_API bool SetGetPerformanceGroupsCallback(JSContext*,
                                                          GetGroupsCallback,
                                                          void*);

/**
 * Hint that we expect a crash. Currently, the only thing that cares is the
 * breakpad injector, which (if loaded) will suppress minidump generation.
 */
extern JS_PUBLIC_API void NoteIntentionalCrash();

} /* namespace js */

namespace js {

enum class CompletionKind { Normal, Return, Throw };

} /* namespace js */

#endif /* jsapi_h */