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 OwnHandle_h 32 #define OwnHandle_h 33 34 #include <v8.h> 35 36 namespace WebCore { 37 38 template<typename T> 39 class OwnHandle { 40 public: OwnHandle()41 OwnHandle() { } OwnHandle(v8::Handle<T> handle)42 explicit OwnHandle(v8::Handle<T> handle) : m_handle(v8::Persistent<T>::New(handle)) { } ~OwnHandle()43 ~OwnHandle() { clear(); } 44 get()45 v8::Handle<T> get() const { return m_handle; } set(v8::Handle<T> handle)46 void set(v8::Handle<T> handle) { clear(); m_handle = v8::Persistent<T>::New(handle); } 47 48 // Note: This is clear in the OwnPtr sense, not the v8::Handle sense. clear()49 void clear() 50 { 51 if (m_handle.IsEmpty()) 52 return; 53 if (m_handle.IsWeak()) 54 m_handle.ClearWeak(); 55 m_handle.Dispose(); 56 m_handle.Clear(); 57 } 58 59 // Make the underlying handle weak. The client doesn't get a callback, 60 // we just make the handle empty. makeWeak()61 void makeWeak() 62 { 63 if (m_handle.IsEmpty()) 64 return; 65 m_handle.MakeWeak(this, &OwnHandle<T>::weakCallback); 66 } 67 68 private: weakCallback(v8::Persistent<v8::Value> object,void * ownHandle)69 static void weakCallback(v8::Persistent<v8::Value> object, void* ownHandle) 70 { 71 OwnHandle<T>* handle = static_cast<OwnHandle<T>*>(ownHandle); 72 handle->clear(); 73 } 74 75 v8::Persistent<T> m_handle; 76 }; 77 78 } // namespace WebCore 79 80 #endif // OwnHandle_h 81