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 file, 5 * You can obtain one at http://mozilla.org/MPL/2.0/. */ 6 7 /** 8 * A simplere nsIGlobalObject implementation that can be used to set up a new 9 * global without anything interesting in it other than the JS builtins. This 10 * is safe to use on both mainthread and worker threads. 11 */ 12 13 #ifndef mozilla_dom_SimpleGlobalObject_h__ 14 #define mozilla_dom_SimpleGlobalObject_h__ 15 16 #include "nsIGlobalObject.h" 17 #include "nsWrapperCache.h" 18 #include "js/TypeDecls.h" 19 #include "nsISupportsImpl.h" 20 #include "nsCycleCollectionParticipant.h" 21 22 namespace mozilla { 23 namespace dom { 24 25 class SimpleGlobalObject : public nsIGlobalObject, 26 public nsWrapperCache 27 { 28 public: 29 enum class GlobalType { 30 BindingDetail, // Should only be used by DOM bindings code. 31 WorkerDebuggerSandbox, 32 NotSimpleGlobal // Sentinel to be used by BasicGlobalType. 33 }; 34 35 // Create a new JS global object that can be used to do some work. This 36 // global will NOT have any DOM APIs exposed in it, will not be visible to the 37 // debugger, and will not have a useful concept of principals, so don't try to 38 // use it with any DOM objects. Apart from that, running code with 39 // side-effects is safe in this global. Importantly, when you are first 40 // handed this global it's guaranteed to have pristine built-ins. The 41 // corresponding nsIGlobalObject* for this global object will be a 42 // SimpleGlobalObject of the type provided; JS_GetPrivate on the returned 43 // JSObject* will return the SimpleGlobalObject*. 44 // 45 // If the provided prototype value is undefined, it is ignored. If it's an 46 // object or null, it's set as the prototype of the created global. If it's 47 // anything else, this function returns null. 48 // 49 // Note that creating new globals is not cheap and should not be done 50 // gratuitously. Please think carefully before you use this function. 51 static JSObject* Create(GlobalType globalType, 52 JS::Handle<JS::Value> proto = 53 JS::UndefinedHandleValue); 54 55 NS_DECL_CYCLE_COLLECTING_ISUPPORTS NS_DECL_CYCLE_COLLECTION_SCRIPT_HOLDER_CLASS_AMBIGUOUS(SimpleGlobalObject,nsIGlobalObject)56 NS_DECL_CYCLE_COLLECTION_SCRIPT_HOLDER_CLASS_AMBIGUOUS(SimpleGlobalObject, 57 nsIGlobalObject) 58 59 // Gets the GlobalType of this SimpleGlobalObject. 60 GlobalType Type() const 61 { 62 return mType; 63 } 64 65 // Gets the GlobalType of the SimpleGlobalObject for the given JSObject*, if 66 // the given JSObject* is the global corresponding to a SimpleGlobalObject. 67 // Oherwise, returns GlobalType::NotSimpleGlobal. 68 static GlobalType SimpleGlobalType(JSObject* obj); 69 GetGlobalJSObject()70 virtual JSObject *GetGlobalJSObject() override 71 { 72 return GetWrapper(); 73 } 74 WrapObject(JSContext * cx,JS::Handle<JSObject * > aGivenProto)75 virtual JSObject* WrapObject(JSContext* cx, 76 JS::Handle<JSObject*> aGivenProto) override 77 { 78 MOZ_CRASH("SimpleGlobalObject doesn't use DOM bindings!"); 79 } 80 81 private: SimpleGlobalObject(JSObject * global,GlobalType type)82 SimpleGlobalObject(JSObject *global, GlobalType type) 83 : mType(type) 84 { 85 SetWrapper(global); 86 } 87 ~SimpleGlobalObject()88 virtual ~SimpleGlobalObject() 89 { 90 ClearWrapper(); 91 } 92 93 const GlobalType mType; 94 }; 95 96 } // namespace dom 97 } // namespace mozilla 98 99 #endif /* mozilla_dom_SimpleGlobalObject_h__ */ 100