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