1 /* 2 * Copyright (C) 2009 Google Inc. All rights reserved. 3 * 4 * Redistribution and use in source and binary forms, with or without 5 * modification, are permitted provided that the following conditions are 6 * met: 7 * 8 * * Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * * Redistributions in binary form must reproduce the above 11 * copyright notice, this list of conditions and the following disclaimer 12 * in the documentation and/or other materials provided with the 13 * distribution. 14 * * Neither the name of Google Inc. nor the names of its 15 * contributors may be used to endorse or promote products derived from 16 * this software without specific prior written permission. 17 * 18 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 19 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 20 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 21 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 22 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 23 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 24 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 25 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 26 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 27 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 28 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 29 */ 30 31 #ifndef V8IsolatedContext_h 32 #define V8IsolatedContext_h 33 34 #include "IsolatedWorld.h" 35 #include "ScriptSourceCode.h" // for WebCore::ScriptSourceCode 36 #include "V8DOMWindow.h" 37 #include "V8Proxy.h" 38 #include "V8Utilities.h" 39 #include <v8.h> 40 41 namespace WebCore { 42 43 class V8Proxy; 44 45 // V8IsolatedContext 46 // 47 // V8IsolatedContext represents a isolated execution environment for 48 // JavaScript. Each isolated world executes in parallel with the main 49 // JavaScript world. An isolated world has access to the same DOM data 50 // structures as the main world but none of the JavaScript pointers. 51 // 52 // It is an error to ever share a JavaScript pointer between two isolated 53 // worlds or between an isolated world and the main world. Because 54 // isolated worlds have access to the DOM, they need their own DOM wrappers 55 // to avoid having pointers to the main world's DOM wrappers (which are 56 // JavaScript objects). 57 class V8IsolatedContext { 58 public: 59 // Creates an isolated world. To destroy it, call destroy(). 60 // This will delete the isolated world when the context it owns is GC'd. 61 V8IsolatedContext(V8Proxy* proxy, int extensionGroup); 62 ~V8IsolatedContext(); 63 64 // Call this to destroy the isolated world. It will be deleted sometime 65 // after this call, once all script references to the world's context 66 // have been dropped. 67 void destroy(); 68 69 // Returns the isolated world associated with 70 // v8::Context::GetEntered(). Because worlds are isolated, the entire 71 // JavaScript call stack should be from the same isolated world. 72 // Returns 0 if the entered context is from the main world. 73 // 74 // FIXME: Consider edge cases with DOM mutation events that might 75 // violate this invariant. 76 // getEntered()77 static V8IsolatedContext* getEntered() 78 { 79 // This is a temporary performance optimization. Essentially, 80 // GetHiddenValue is too slow for this code path. We need to get the 81 // V8 team to add a real property to v8::Context for isolated worlds. 82 // Until then, we optimize the common case of not having any isolated 83 // worlds at all. 84 if (!IsolatedWorld::count()) 85 return 0; 86 if (!v8::Context::InContext()) 87 return 0; 88 return reinterpret_cast<V8IsolatedContext*>(getGlobalObject(v8::Context::GetEntered())->GetPointerFromInternalField(V8DOMWindow::enteredIsolatedWorldIndex)); 89 } 90 context()91 v8::Handle<v8::Context> context() { return m_context->get(); } sharedContext()92 PassRefPtr<SharedPersistent<v8::Context> > sharedContext() { return m_context; } 93 world()94 IsolatedWorld* world() const { return m_world.get(); } 95 96 private: getGlobalObject(v8::Handle<v8::Context> context)97 static v8::Handle<v8::Object> getGlobalObject(v8::Handle<v8::Context> context) 98 { 99 return v8::Handle<v8::Object>::Cast(context->Global()->GetPrototype()); 100 } 101 102 // Called by the garbage collector when our JavaScript context is about 103 // to be destroyed. 104 static void contextWeakReferenceCallback(v8::Persistent<v8::Value> object, void* isolatedContext); 105 106 // The underlying v8::Context. This object is keep on the heap as 107 // long as |m_context| has not been garbage collected. 108 RefPtr<SharedPersistent<v8::Context> > m_context; 109 110 RefPtr<IsolatedWorld> m_world; 111 }; 112 113 } // namespace WebCore 114 115 #endif // V8IsolatedContext_h 116