1 /* 2 * Copyright (C) 2011 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 V8RecursionScope_h 32 #define V8RecursionScope_h 33 34 #include "bindings/v8/V8PerIsolateData.h" 35 #include "core/dom/ExecutionContext.h" 36 #include "core/dom/ScriptForbiddenScope.h" 37 #include "wtf/Noncopyable.h" 38 #include <v8.h> 39 40 namespace WebCore { 41 42 // C++ calls into script contexts which are "owned" by WebKit (created in a 43 // process where WebKit.cpp initializes v8) must declare their type: 44 // 45 // 1. Calls into page/author script from a frame 46 // 2. Calls into page/author script from a worker 47 // 3. Calls into internal script (typically setup/teardown work) 48 // 49 // Debug-time checking of this is enforced via this class. 50 // 51 // Calls of type (1) should generally go through ScriptController, as inspector 52 // instrumentation is needed. ScriptController allocates V8RecursionScope for you. 53 // Calls of type (2) should always stack-allocate a V8RecursionScope in the same 54 // block as the call into script. Calls of type (3) should stack allocate a 55 // V8RecursionScope::MicrotaskSuppression -- this skips work that is spec'd to 56 // happen at the end of the outer-most script stack frame of calls into page script: 57 // 58 // http://www.whatwg.org/specs/web-apps/current-work/#perform-a-microtask-checkpoint 59 class V8RecursionScope { 60 WTF_MAKE_NONCOPYABLE(V8RecursionScope); 61 public: 62 V8RecursionScope(v8::Isolate* isolate, ExecutionContext* context) 63 : m_isolate(isolate) 64 , m_executionContext(*context) 65 { 66 V8PerIsolateData::from(m_isolate)->incrementRecursionLevel(); 67 ASSERT(!ScriptForbiddenScope::isScriptForbidden()); 68 // If you want V8 to autorun microtasks, this class needs to have a 69 // v8::Isolate::SuppressMicrotaskExecutionScope member. 70 ASSERT(!isolate->WillAutorunMicrotasks()); 71 } 72 73 ~V8RecursionScope() 74 { 75 if (!V8PerIsolateData::from(m_isolate)->decrementRecursionLevel()) 76 didLeaveScriptContext(); 77 } 78 79 static int recursionLevel(v8::Isolate* isolate) 80 { 81 return V8PerIsolateData::from(isolate)->recursionLevel(); 82 } 83 84 #ifndef NDEBUG 85 static bool properlyUsed(v8::Isolate* isolate) 86 { 87 return recursionLevel(isolate) > 0 || V8PerIsolateData::from(isolate)->internalScriptRecursionLevel() > 0; 88 } 89 #endif 90 91 class MicrotaskSuppression { 92 public: 93 MicrotaskSuppression(v8::Isolate* isolate) 94 #ifndef NDEBUG 95 : m_isolate(isolate) 96 #endif 97 { 98 ASSERT(!ScriptForbiddenScope::isScriptForbidden()); 99 #ifndef NDEBUG 100 V8PerIsolateData::from(m_isolate)->incrementInternalScriptRecursionLevel(); 101 #endif 102 } 103 104 ~MicrotaskSuppression() 105 { 106 #ifndef NDEBUG 107 V8PerIsolateData::from(m_isolate)->decrementInternalScriptRecursionLevel(); 108 #endif 109 } 110 111 private: 112 #ifndef NDEBUG 113 v8::Isolate* m_isolate; 114 #endif 115 }; 116 117 private: 118 void didLeaveScriptContext(); 119 120 v8::Isolate* m_isolate; 121 ExecutionContext& m_executionContext; 122 }; 123 124 } // namespace WebCore 125 126 #endif // V8RecursionScope_h 127