1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
2 * vim: set ts=8 sts=2 et sw=2 tw=80:
3 * This Source Code Form is subject to the terms of the Mozilla Public
4 * License, v. 2.0. If a copy of the MPL was not distributed with this
5 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
6
7 #include "mozilla/Assertions.h" // MOZ_ASSERT
8
9 #include <stdint.h> // uint8_t, uint32_t
10
11 #include "jstypes.h" // JS_PUBLIC_API
12
13 #include "js/ArrayBufferMaybeShared.h"
14 #include "vm/ArrayBufferObject.h" // js::ArrayBufferObject
15 #include "vm/JSObject.h" // JSObject
16 #include "vm/SharedArrayObject.h" // js::SharedArrayBufferObject
17 #include "vm/SharedMem.h" // SharedMem
18
19 using namespace js;
20
IsArrayBufferObjectMaybeShared(JSObject * obj)21 JS_PUBLIC_API bool JS::IsArrayBufferObjectMaybeShared(JSObject* obj) {
22 return obj->canUnwrapAs<ArrayBufferObjectMaybeShared>();
23 }
24
UnwrapArrayBufferMaybeShared(JSObject * obj)25 JS_PUBLIC_API JSObject* JS::UnwrapArrayBufferMaybeShared(JSObject* obj) {
26 return obj->maybeUnwrapIf<ArrayBufferObjectMaybeShared>();
27 }
28
GetArrayBufferMaybeSharedLengthAndData(JSObject * obj,size_t * length,bool * isSharedMemory,uint8_t ** data)29 JS_PUBLIC_API void JS::GetArrayBufferMaybeSharedLengthAndData(
30 JSObject* obj, size_t* length, bool* isSharedMemory, uint8_t** data) {
31 MOZ_ASSERT(obj->is<ArrayBufferObjectMaybeShared>());
32
33 if (obj->is<SharedArrayBufferObject>()) {
34 auto* buffer = &obj->as<SharedArrayBufferObject>();
35 *length = buffer->byteLength();
36 *data = buffer->dataPointerShared().unwrap();
37 *isSharedMemory = true;
38 } else {
39 auto* buffer = &obj->as<ArrayBufferObject>();
40 *length = buffer->byteLength();
41 *data = buffer->dataPointer();
42 *isSharedMemory = false;
43 }
44 }
45
GetArrayBufferMaybeSharedData(JSObject * obj,bool * isSharedMemory,const JS::AutoRequireNoGC &)46 JS_PUBLIC_API uint8_t* JS::GetArrayBufferMaybeSharedData(
47 JSObject* obj, bool* isSharedMemory, const JS::AutoRequireNoGC&) {
48 MOZ_ASSERT(obj->maybeUnwrapIf<ArrayBufferObjectMaybeShared>());
49
50 if (ArrayBufferObject* aobj = obj->maybeUnwrapIf<ArrayBufferObject>()) {
51 *isSharedMemory = false;
52 return aobj->dataPointer();
53 } else if (SharedArrayBufferObject* saobj =
54 obj->maybeUnwrapIf<SharedArrayBufferObject>()) {
55 *isSharedMemory = true;
56 return saobj->dataPointerShared().unwrap();
57 }
58
59 return nullptr;
60 }
61
IsLargeArrayBufferMaybeShared(JSObject * obj)62 JS_PUBLIC_API bool JS::IsLargeArrayBufferMaybeShared(JSObject* obj) {
63 #ifdef JS_64BIT
64 obj = UnwrapArrayBufferMaybeShared(obj);
65 MOZ_ASSERT(obj);
66 size_t len = obj->is<ArrayBufferObject>()
67 ? obj->as<ArrayBufferObject>().byteLength()
68 : obj->as<SharedArrayBufferObject>().byteLength();
69 return len > ArrayBufferObject::MaxByteLengthForSmallBuffer;
70 #else
71 // Large ArrayBuffers are not supported on 32-bit.
72 MOZ_ASSERT(ArrayBufferObject::maxBufferByteLength() ==
73 ArrayBufferObject::MaxByteLengthForSmallBuffer);
74 return false;
75 #endif
76 }
77