1 /* 2 * Copyright (C) 2006, 2007, 2008, 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 V8NodeFilterCondition_h 32 #define V8NodeFilterCondition_h 33 34 #include "bindings/v8/ScopedPersistent.h" 35 #include "core/dom/NodeFilterCondition.h" 36 #include <v8.h> 37 #include "wtf/PassRefPtr.h" 38 39 namespace WebCore { 40 41 class Node; 42 class ScriptState; 43 44 // V8NodeFilterCondition maintains a Javascript implemented callback for 45 // filtering Node returned by NodeIterator/TreeWalker. 46 // A NodeFilterCondition is referenced by a NodeFilter, and A NodeFilter is 47 // referenced by a NodeIterator/TreeWalker. As V8NodeFilterCondition maintains 48 // a Javascript callback which may reference Document, we need to avoid circular 49 // reference spanning V8/Blink object space. 50 // To address this issue, V8NodeFilterCondition holds a weak reference to 51 // |m_filter|, the Javascript value, and the whole reference is exposed to V8 to 52 // let V8 GC handle collection of |m_filter|. 53 // (DOM) 54 // NodeIterator ----RefPtr----> NodeFilter ----RefPtr----> NodeFilterCondition 55 // | ^ | ^ | 56 // weak | weak | ScopedPersistent(weak) 57 // | RefPtr | RefPtr | 58 // v | v | v 59 // NodeIterator --HiddenValue--> NodeFilter --HiddenValue--> JS Callback 60 // (V8) 61 class V8NodeFilterCondition : public NodeFilterCondition { 62 public: 63 static PassRefPtr<V8NodeFilterCondition> create(v8::Handle<v8::Value> filter, v8::Handle<v8::Object> owner) 64 { 65 return adoptRef(new V8NodeFilterCondition(filter, owner)); 66 } 67 68 virtual ~V8NodeFilterCondition(); 69 70 virtual short acceptNode(ScriptState*, Node*) const; 71 72 private: 73 // As the value |filter| is maintained by V8GC, the |owner| which references 74 // V8NodeFilterCondition, usually a wrapper of NodeFilter, is specified here 75 // to hold a strong reference to |filter|. 76 V8NodeFilterCondition(v8::Handle<v8::Value> filter, v8::Handle<v8::Object> owner); 77 78 static void makeWeakCallback(v8::Isolate*, v8::Persistent<v8::Value>*, V8NodeFilterCondition*); 79 80 ScopedPersistent<v8::Value> m_filter; 81 }; 82 83 } // namespace WebCore 84 85 #endif // V8NodeFilterCondition_h 86
