1 /* 2 * Copyright (C) 2014 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 WTF_RawPtr_h 32 #define WTF_RawPtr_h 33 34 #include <algorithm> 35 #include <stdint.h> 36 37 #include "wtf/HashTableDeletedValueType.h" 38 39 // RawPtr is a simple wrapper for a raw pointer that provides the 40 // interface (get, clear) of other pointer types such as RefPtr, 41 // Persistent and Member. This is used for the Blink garbage 42 // collection work in order to be able to write shared code that will 43 // use reference counting or garbage collection based on a 44 // compile-time flag. 45 46 namespace WTF { 47 48 template<typename T> 49 class RawPtr { 50 WTF_DISALLOW_CONSTRUCTION_FROM_ZERO(RawPtr); 51 WTF_DISALLOW_ZERO_ASSIGNMENT(RawPtr); 52 public: 53 RawPtr() 54 { 55 #if ENABLE(ASSERT) 56 m_ptr = reinterpret_cast<T*>(rawPtrZapValue); 57 #endif 58 } 59 RawPtr(std::nullptr_t) : m_ptr(0) { } 60 RawPtr(T* ptr) : m_ptr(ptr) { } 61 explicit RawPtr(T& reference) : m_ptr(&reference) { } 62 RawPtr(const RawPtr& other) 63 : m_ptr(other.get()) 64 { 65 } 66 67 template<typename U> 68 RawPtr(const RawPtr<U>& other) 69 : m_ptr(other.get()) 70 { 71 } 72 73 // Hash table deleted values, which are only constructed and never copied or destroyed. 74 RawPtr(HashTableDeletedValueType) : m_ptr(hashTableDeletedValue()) { } 75 bool isHashTableDeletedValue() const { return m_ptr == hashTableDeletedValue(); } 76 77 T* get() const { return m_ptr; } 78 void clear() { m_ptr = 0; } 79 // FIXME: oilpan: Remove release and leakRef once we remove RefPtrWillBeRawPtr. 80 RawPtr<T> release() 81 { 82 RawPtr<T> tmp = m_ptr; 83 m_ptr = 0; 84 return tmp; 85 } 86 T* leakRef() 87 { 88 T* ptr = m_ptr; 89 m_ptr = 0; 90 return ptr; 91 } 92 T* leakPtr() 93 { 94 T* ptr = m_ptr; 95 m_ptr = 0; 96 return ptr; 97 } 98 99 template<typename U> 100 RawPtr& operator=(U* ptr) 101 { 102 m_ptr = ptr; 103 return *this; 104 } 105 106 template<typename U> 107 RawPtr& operator=(RawPtr<U> ptr) 108 { 109 m_ptr = ptr.get(); 110 return *this; 111 } 112 113 RawPtr& operator=(std::nullptr_t) 114 { 115 m_ptr = 0; 116 return *this; 117 } 118 119 operator T*() const { return m_ptr; } 120 T& operator*() const { return *m_ptr; } 121 T* operator->() const { return m_ptr; } 122 bool operator!() const { return !m_ptr; } 123 124 void swap(RawPtr& o) 125 { 126 std::swap(m_ptr, o.m_ptr); 127 } 128 129 static T* hashTableDeletedValue() { return reinterpret_cast<T*>(-1); } 130 131 private: 132 static const uintptr_t rawPtrZapValue = 0x3a3a3a3a; 133 T* m_ptr; 134 }; 135 136 template<typename T, typename U> inline RawPtr<T> static_pointer_cast(const RawPtr<U>& p) 137 { 138 return RawPtr<T>(static_cast<T*>(p.get())); 139 } 140 141 template<typename T> inline T* getPtr(const RawPtr<T>& p) 142 { 143 return p.get(); 144 } 145 146 } // namespace WTF 147 148 using WTF::RawPtr; 149 150 #endif 151