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1 /* |
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2 * Copyright (C) 2005 The Android Open Source Project |
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3 * |
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4 * Licensed under the Apache License, Version 2.0 (the "License"); |
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5 * you may not use this file except in compliance with the License. |
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6 * You may obtain a copy of the License at |
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7 * |
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8 * http://www.apache.org/licenses/LICENSE-2.0 |
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9 * |
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10 * Unless required by applicable law or agreed to in writing, software |
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11 * distributed under the License is distributed on an "AS IS" BASIS, |
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12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
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13 * See the License for the specific language governing permissions and |
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14 * limitations under the License. |
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15 */ |
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16 |
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17 #ifndef ANDROID_REF_BASE_H |
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18 #define ANDROID_REF_BASE_H |
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19 |
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20 #include <cutils/atomic.h> |
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21 |
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22 #include <stdint.h> |
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23 #include <sys/types.h> |
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24 #include <stdlib.h> |
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25 #include <string.h> |
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26 |
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27 #include <utils/StrongPointer.h> |
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28 |
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29 // --------------------------------------------------------------------------- |
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30 namespace android { |
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31 |
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32 class TextOutput; |
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33 TextOutput& printWeakPointer(TextOutput& to, const void* val); |
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34 |
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35 // --------------------------------------------------------------------------- |
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36 |
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37 #define COMPARE_WEAK(_op_) \ |
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38 inline bool operator _op_ (const sp<T>& o) const { \ |
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39 return m_ptr _op_ o.m_ptr; \ |
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40 } \ |
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41 inline bool operator _op_ (const T* o) const { \ |
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42 return m_ptr _op_ o; \ |
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43 } \ |
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44 template<typename U> \ |
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45 inline bool operator _op_ (const sp<U>& o) const { \ |
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46 return m_ptr _op_ o.m_ptr; \ |
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47 } \ |
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48 template<typename U> \ |
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49 inline bool operator _op_ (const U* o) const { \ |
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50 return m_ptr _op_ o; \ |
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51 } |
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52 |
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53 // --------------------------------------------------------------------------- |
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54 class ReferenceMover; |
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55 class ReferenceConverterBase { |
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56 public: |
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57 virtual size_t getReferenceTypeSize() const = 0; |
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58 virtual void* getReferenceBase(void const*) const = 0; |
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59 inline virtual ~ReferenceConverterBase() { } |
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60 }; |
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61 |
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62 // --------------------------------------------------------------------------- |
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63 |
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64 class RefBase |
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65 { |
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66 public: |
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67 void incStrong(const void* id) const; |
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68 void decStrong(const void* id) const; |
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69 |
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70 void forceIncStrong(const void* id) const; |
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71 |
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72 //! DEBUGGING ONLY: Get current strong ref count. |
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73 int32_t getStrongCount() const; |
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74 |
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75 class weakref_type |
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76 { |
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77 public: |
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78 RefBase* refBase() const; |
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79 |
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80 void incWeak(const void* id); |
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81 void decWeak(const void* id); |
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82 |
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83 // acquires a strong reference if there is already one. |
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84 bool attemptIncStrong(const void* id); |
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85 |
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86 // acquires a weak reference if there is already one. |
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87 // This is not always safe. see ProcessState.cpp and BpBinder.cpp |
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88 // for proper use. |
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89 bool attemptIncWeak(const void* id); |
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90 |
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91 //! DEBUGGING ONLY: Get current weak ref count. |
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92 int32_t getWeakCount() const; |
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93 |
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94 //! DEBUGGING ONLY: Print references held on object. |
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95 void printRefs() const; |
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96 |
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97 //! DEBUGGING ONLY: Enable tracking for this object. |
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98 // enable -- enable/disable tracking |
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99 // retain -- when tracking is enable, if true, then we save a stack trace |
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100 // for each reference and dereference; when retain == false, we |
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101 // match up references and dereferences and keep only the |
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102 // outstanding ones. |
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103 |
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104 void trackMe(bool enable, bool retain); |
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105 }; |
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106 |
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107 weakref_type* createWeak(const void* id) const; |
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108 |
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109 weakref_type* getWeakRefs() const; |
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110 |
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111 //! DEBUGGING ONLY: Print references held on object. |
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112 inline void printRefs() const { getWeakRefs()->printRefs(); } |
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113 |
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114 //! DEBUGGING ONLY: Enable tracking of object. |
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115 inline void trackMe(bool enable, bool retain) |
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116 { |
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117 getWeakRefs()->trackMe(enable, retain); |
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118 } |
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119 |
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120 typedef RefBase basetype; |
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121 |
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122 protected: |
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123 RefBase(); |
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124 virtual ~RefBase(); |
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125 |
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126 //! Flags for extendObjectLifetime() |
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127 enum { |
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128 OBJECT_LIFETIME_STRONG = 0x0000, |
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129 OBJECT_LIFETIME_WEAK = 0x0001, |
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130 OBJECT_LIFETIME_MASK = 0x0001 |
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131 }; |
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132 |
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133 void extendObjectLifetime(int32_t mode); |
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134 |
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135 //! Flags for onIncStrongAttempted() |
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136 enum { |
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137 FIRST_INC_STRONG = 0x0001 |
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138 }; |
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139 |
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140 virtual void onFirstRef(); |
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141 virtual void onLastStrongRef(const void* id); |
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142 virtual bool onIncStrongAttempted(uint32_t flags, const void* id); |
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143 virtual void onLastWeakRef(const void* id); |
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144 |
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145 private: |
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146 friend class ReferenceMover; |
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147 static void moveReferences(void* d, void const* s, size_t n, |
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148 const ReferenceConverterBase& caster); |
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149 |
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150 private: |
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151 friend class weakref_type; |
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152 class weakref_impl; |
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153 |
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154 RefBase(const RefBase& o); |
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155 RefBase& operator=(const RefBase& o); |
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156 |
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157 weakref_impl* const mRefs; |
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158 }; |
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159 |
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160 // --------------------------------------------------------------------------- |
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161 |
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162 template <class T> |
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163 class LightRefBase |
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164 { |
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165 public: |
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166 inline LightRefBase() : mCount(0) { } |
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167 inline void incStrong(const void* id) const { |
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168 android_atomic_inc(&mCount); |
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169 } |
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170 inline void decStrong(const void* id) const { |
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171 if (android_atomic_dec(&mCount) == 1) { |
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172 delete static_cast<const T*>(this); |
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173 } |
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174 } |
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175 //! DEBUGGING ONLY: Get current strong ref count. |
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176 inline int32_t getStrongCount() const { |
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177 return mCount; |
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178 } |
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179 |
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180 typedef LightRefBase<T> basetype; |
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181 |
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182 protected: |
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183 inline ~LightRefBase() { } |
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184 |
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185 private: |
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186 friend class ReferenceMover; |
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187 inline static void moveReferences(void* d, void const* s, size_t n, |
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188 const ReferenceConverterBase& caster) { } |
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189 |
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190 private: |
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191 mutable volatile int32_t mCount; |
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192 }; |
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193 |
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194 // --------------------------------------------------------------------------- |
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195 |
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196 template <typename T> |
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197 class wp |
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198 { |
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199 public: |
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200 typedef typename RefBase::weakref_type weakref_type; |
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201 |
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202 inline wp() : m_ptr(0) { } |
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203 |
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204 wp(T* other); |
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205 wp(const wp<T>& other); |
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206 wp(const sp<T>& other); |
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207 template<typename U> wp(U* other); |
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208 template<typename U> wp(const sp<U>& other); |
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209 template<typename U> wp(const wp<U>& other); |
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210 |
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211 ~wp(); |
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212 |
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213 // Assignment |
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214 |
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215 wp& operator = (T* other); |
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216 wp& operator = (const wp<T>& other); |
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217 wp& operator = (const sp<T>& other); |
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218 |
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219 template<typename U> wp& operator = (U* other); |
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220 template<typename U> wp& operator = (const wp<U>& other); |
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221 template<typename U> wp& operator = (const sp<U>& other); |
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222 |
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223 void set_object_and_refs(T* other, weakref_type* refs); |
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224 |
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225 // promotion to sp |
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226 |
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227 sp<T> promote() const; |
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228 |
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229 // Reset |
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230 |
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231 void clear(); |
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232 |
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233 // Accessors |
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234 |
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235 inline weakref_type* get_refs() const { return m_refs; } |
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236 |
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237 inline T* unsafe_get() const { return m_ptr; } |
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238 |
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239 // Operators |
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240 |
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241 COMPARE_WEAK(==) |
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242 COMPARE_WEAK(!=) |
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243 COMPARE_WEAK(>) |
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244 COMPARE_WEAK(<) |
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245 COMPARE_WEAK(<=) |
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246 COMPARE_WEAK(>=) |
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247 |
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248 inline bool operator == (const wp<T>& o) const { |
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249 return (m_ptr == o.m_ptr) && (m_refs == o.m_refs); |
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250 } |
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251 template<typename U> |
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252 inline bool operator == (const wp<U>& o) const { |
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253 return m_ptr == o.m_ptr; |
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254 } |
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255 |
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256 inline bool operator > (const wp<T>& o) const { |
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257 return (m_ptr == o.m_ptr) ? (m_refs > o.m_refs) : (m_ptr > o.m_ptr); |
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258 } |
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259 template<typename U> |
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260 inline bool operator > (const wp<U>& o) const { |
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261 return (m_ptr == o.m_ptr) ? (m_refs > o.m_refs) : (m_ptr > o.m_ptr); |
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262 } |
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263 |
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264 inline bool operator < (const wp<T>& o) const { |
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265 return (m_ptr == o.m_ptr) ? (m_refs < o.m_refs) : (m_ptr < o.m_ptr); |
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266 } |
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267 template<typename U> |
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268 inline bool operator < (const wp<U>& o) const { |
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269 return (m_ptr == o.m_ptr) ? (m_refs < o.m_refs) : (m_ptr < o.m_ptr); |
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270 } |
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271 inline bool operator != (const wp<T>& o) const { return m_refs != o.m_refs; } |
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272 template<typename U> inline bool operator != (const wp<U>& o) const { return !operator == (o); } |
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273 inline bool operator <= (const wp<T>& o) const { return !operator > (o); } |
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274 template<typename U> inline bool operator <= (const wp<U>& o) const { return !operator > (o); } |
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275 inline bool operator >= (const wp<T>& o) const { return !operator < (o); } |
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276 template<typename U> inline bool operator >= (const wp<U>& o) const { return !operator < (o); } |
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277 |
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278 private: |
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279 template<typename Y> friend class sp; |
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280 template<typename Y> friend class wp; |
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281 |
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282 T* m_ptr; |
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283 weakref_type* m_refs; |
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284 }; |
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285 |
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286 template <typename T> |
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287 TextOutput& operator<<(TextOutput& to, const wp<T>& val); |
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288 |
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289 #undef COMPARE_WEAK |
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290 |
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291 // --------------------------------------------------------------------------- |
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292 // No user serviceable parts below here. |
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293 |
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294 template<typename T> |
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295 wp<T>::wp(T* other) |
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296 : m_ptr(other) |
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297 { |
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298 if (other) m_refs = other->createWeak(this); |
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299 } |
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300 |
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301 template<typename T> |
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302 wp<T>::wp(const wp<T>& other) |
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303 : m_ptr(other.m_ptr), m_refs(other.m_refs) |
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304 { |
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305 if (m_ptr) m_refs->incWeak(this); |
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306 } |
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307 |
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308 template<typename T> |
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309 wp<T>::wp(const sp<T>& other) |
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310 : m_ptr(other.m_ptr) |
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311 { |
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312 if (m_ptr) { |
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313 m_refs = m_ptr->createWeak(this); |
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314 } |
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315 } |
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316 |
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317 template<typename T> template<typename U> |
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318 wp<T>::wp(U* other) |
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319 : m_ptr(other) |
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320 { |
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321 if (other) m_refs = other->createWeak(this); |
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322 } |
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323 |
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324 template<typename T> template<typename U> |
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325 wp<T>::wp(const wp<U>& other) |
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326 : m_ptr(other.m_ptr) |
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327 { |
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328 if (m_ptr) { |
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329 m_refs = other.m_refs; |
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330 m_refs->incWeak(this); |
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331 } |
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332 } |
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333 |
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334 template<typename T> template<typename U> |
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335 wp<T>::wp(const sp<U>& other) |
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336 : m_ptr(other.m_ptr) |
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337 { |
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338 if (m_ptr) { |
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339 m_refs = m_ptr->createWeak(this); |
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340 } |
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341 } |
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342 |
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343 template<typename T> |
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344 wp<T>::~wp() |
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345 { |
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346 if (m_ptr) m_refs->decWeak(this); |
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347 } |
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348 |
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349 template<typename T> |
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350 wp<T>& wp<T>::operator = (T* other) |
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351 { |
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352 weakref_type* newRefs = |
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353 other ? other->createWeak(this) : 0; |
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354 if (m_ptr) m_refs->decWeak(this); |
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355 m_ptr = other; |
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356 m_refs = newRefs; |
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357 return *this; |
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358 } |
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359 |
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360 template<typename T> |
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361 wp<T>& wp<T>::operator = (const wp<T>& other) |
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362 { |
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363 weakref_type* otherRefs(other.m_refs); |
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364 T* otherPtr(other.m_ptr); |
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365 if (otherPtr) otherRefs->incWeak(this); |
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366 if (m_ptr) m_refs->decWeak(this); |
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367 m_ptr = otherPtr; |
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368 m_refs = otherRefs; |
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369 return *this; |
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370 } |
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371 |
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372 template<typename T> |
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373 wp<T>& wp<T>::operator = (const sp<T>& other) |
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374 { |
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375 weakref_type* newRefs = |
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376 other != NULL ? other->createWeak(this) : 0; |
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377 T* otherPtr(other.m_ptr); |
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378 if (m_ptr) m_refs->decWeak(this); |
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379 m_ptr = otherPtr; |
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380 m_refs = newRefs; |
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381 return *this; |
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382 } |
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383 |
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384 template<typename T> template<typename U> |
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385 wp<T>& wp<T>::operator = (U* other) |
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386 { |
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387 weakref_type* newRefs = |
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388 other ? other->createWeak(this) : 0; |
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389 if (m_ptr) m_refs->decWeak(this); |
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390 m_ptr = other; |
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391 m_refs = newRefs; |
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392 return *this; |
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393 } |
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394 |
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395 template<typename T> template<typename U> |
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396 wp<T>& wp<T>::operator = (const wp<U>& other) |
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397 { |
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398 weakref_type* otherRefs(other.m_refs); |
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399 U* otherPtr(other.m_ptr); |
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400 if (otherPtr) otherRefs->incWeak(this); |
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401 if (m_ptr) m_refs->decWeak(this); |
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402 m_ptr = otherPtr; |
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403 m_refs = otherRefs; |
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404 return *this; |
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405 } |
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406 |
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407 template<typename T> template<typename U> |
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408 wp<T>& wp<T>::operator = (const sp<U>& other) |
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409 { |
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410 weakref_type* newRefs = |
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411 other != NULL ? other->createWeak(this) : 0; |
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412 U* otherPtr(other.m_ptr); |
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413 if (m_ptr) m_refs->decWeak(this); |
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414 m_ptr = otherPtr; |
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415 m_refs = newRefs; |
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416 return *this; |
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417 } |
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418 |
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419 template<typename T> |
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420 void wp<T>::set_object_and_refs(T* other, weakref_type* refs) |
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421 { |
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422 if (other) refs->incWeak(this); |
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423 if (m_ptr) m_refs->decWeak(this); |
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424 m_ptr = other; |
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425 m_refs = refs; |
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426 } |
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427 |
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428 template<typename T> |
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429 sp<T> wp<T>::promote() const |
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430 { |
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431 sp<T> result; |
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432 if (m_ptr && m_refs->attemptIncStrong(&result)) { |
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433 result.set_pointer(m_ptr); |
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434 } |
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435 return result; |
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436 } |
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437 |
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438 template<typename T> |
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439 void wp<T>::clear() |
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440 { |
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441 if (m_ptr) { |
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442 m_refs->decWeak(this); |
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443 m_ptr = 0; |
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444 } |
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445 } |
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446 |
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447 template <typename T> |
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448 inline TextOutput& operator<<(TextOutput& to, const wp<T>& val) |
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449 { |
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450 return printWeakPointer(to, val.unsafe_get()); |
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451 } |
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452 |
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453 // --------------------------------------------------------------------------- |
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454 |
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455 // this class just serves as a namespace so TYPE::moveReferences can stay |
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456 // private. |
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457 |
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458 class ReferenceMover { |
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459 // StrongReferenceCast and WeakReferenceCast do the impedance matching |
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460 // between the generic (void*) implementation in Refbase and the strongly typed |
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461 // template specializations below. |
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462 |
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463 template <typename TYPE> |
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464 struct StrongReferenceCast : public ReferenceConverterBase { |
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465 virtual size_t getReferenceTypeSize() const { return sizeof( sp<TYPE> ); } |
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466 virtual void* getReferenceBase(void const* p) const { |
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467 sp<TYPE> const* sptr(reinterpret_cast<sp<TYPE> const*>(p)); |
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468 return static_cast<typename TYPE::basetype *>(sptr->get()); |
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469 } |
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470 }; |
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471 |
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472 template <typename TYPE> |
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473 struct WeakReferenceCast : public ReferenceConverterBase { |
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474 virtual size_t getReferenceTypeSize() const { return sizeof( wp<TYPE> ); } |
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475 virtual void* getReferenceBase(void const* p) const { |
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476 wp<TYPE> const* sptr(reinterpret_cast<wp<TYPE> const*>(p)); |
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477 return static_cast<typename TYPE::basetype *>(sptr->unsafe_get()); |
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478 } |
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479 }; |
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480 |
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481 public: |
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482 template<typename TYPE> static inline |
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483 void move_references(sp<TYPE>* d, sp<TYPE> const* s, size_t n) { |
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484 memmove(d, s, n*sizeof(sp<TYPE>)); |
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485 StrongReferenceCast<TYPE> caster; |
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486 TYPE::moveReferences(d, s, n, caster); |
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487 } |
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488 template<typename TYPE> static inline |
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489 void move_references(wp<TYPE>* d, wp<TYPE> const* s, size_t n) { |
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490 memmove(d, s, n*sizeof(wp<TYPE>)); |
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491 WeakReferenceCast<TYPE> caster; |
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492 TYPE::moveReferences(d, s, n, caster); |
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493 } |
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494 }; |
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495 |
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496 // specialization for moving sp<> and wp<> types. |
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497 // these are used by the [Sorted|Keyed]Vector<> implementations |
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498 // sp<> and wp<> need to be handled specially, because they do not |
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499 // have trivial copy operation in the general case (see RefBase.cpp |
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500 // when DEBUG ops are enabled), but can be implemented very |
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501 // efficiently in most cases. |
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502 |
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503 template<typename TYPE> inline |
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504 void move_forward_type(sp<TYPE>* d, sp<TYPE> const* s, size_t n) { |
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505 ReferenceMover::move_references(d, s, n); |
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506 } |
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507 |
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508 template<typename TYPE> inline |
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509 void move_backward_type(sp<TYPE>* d, sp<TYPE> const* s, size_t n) { |
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510 ReferenceMover::move_references(d, s, n); |
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511 } |
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512 |
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513 template<typename TYPE> inline |
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514 void move_forward_type(wp<TYPE>* d, wp<TYPE> const* s, size_t n) { |
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515 ReferenceMover::move_references(d, s, n); |
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516 } |
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517 |
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518 template<typename TYPE> inline |
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519 void move_backward_type(wp<TYPE>* d, wp<TYPE> const* s, size_t n) { |
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520 ReferenceMover::move_references(d, s, n); |
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521 } |
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522 |
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523 |
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524 }; // namespace android |
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525 |
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526 // --------------------------------------------------------------------------- |
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527 |
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528 #endif // ANDROID_REF_BASE_H |