7b1516795e
when assigning a smart pointer to another one, we need to make sure to read all the data we need from the right-hand-side reference (the assignee) before we decRef the assigned. This bug would cause linked-list of smart-pointers to fail miserably. Change-Id: Ibb554c15fddf909f7737c632b7c80322e80ea93f
562 lines
14 KiB
C++
562 lines
14 KiB
C++
/*
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* Copyright (C) 2005 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#ifndef ANDROID_REF_BASE_H
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#define ANDROID_REF_BASE_H
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#include <cutils/atomic.h>
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#include <utils/TextOutput.h>
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#include <stdint.h>
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#include <sys/types.h>
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#include <stdlib.h>
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// ---------------------------------------------------------------------------
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namespace android {
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template<typename T> class wp;
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// ---------------------------------------------------------------------------
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#define COMPARE(_op_) \
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inline bool operator _op_ (const sp<T>& o) const { \
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return m_ptr _op_ o.m_ptr; \
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} \
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inline bool operator _op_ (const wp<T>& o) const { \
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return m_ptr _op_ o.m_ptr; \
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} \
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inline bool operator _op_ (const T* o) const { \
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return m_ptr _op_ o; \
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} \
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template<typename U> \
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inline bool operator _op_ (const sp<U>& o) const { \
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return m_ptr _op_ o.m_ptr; \
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} \
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template<typename U> \
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inline bool operator _op_ (const wp<U>& o) const { \
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return m_ptr _op_ o.m_ptr; \
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} \
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template<typename U> \
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inline bool operator _op_ (const U* o) const { \
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return m_ptr _op_ o; \
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}
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// ---------------------------------------------------------------------------
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class RefBase
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{
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public:
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void incStrong(const void* id) const;
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void decStrong(const void* id) const;
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void forceIncStrong(const void* id) const;
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//! DEBUGGING ONLY: Get current strong ref count.
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int32_t getStrongCount() const;
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class weakref_type
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{
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public:
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RefBase* refBase() const;
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void incWeak(const void* id);
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void decWeak(const void* id);
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bool attemptIncStrong(const void* id);
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//! This is only safe if you have set OBJECT_LIFETIME_FOREVER.
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bool attemptIncWeak(const void* id);
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//! DEBUGGING ONLY: Get current weak ref count.
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int32_t getWeakCount() const;
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//! DEBUGGING ONLY: Print references held on object.
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void printRefs() const;
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//! DEBUGGING ONLY: Enable tracking for this object.
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// enable -- enable/disable tracking
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// retain -- when tracking is enable, if true, then we save a stack trace
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// for each reference and dereference; when retain == false, we
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// match up references and dereferences and keep only the
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// outstanding ones.
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void trackMe(bool enable, bool retain);
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};
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weakref_type* createWeak(const void* id) const;
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weakref_type* getWeakRefs() const;
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//! DEBUGGING ONLY: Print references held on object.
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inline void printRefs() const { getWeakRefs()->printRefs(); }
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//! DEBUGGING ONLY: Enable tracking of object.
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inline void trackMe(bool enable, bool retain)
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{
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getWeakRefs()->trackMe(enable, retain);
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}
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protected:
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RefBase();
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virtual ~RefBase();
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//! Flags for extendObjectLifetime()
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enum {
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OBJECT_LIFETIME_WEAK = 0x0001,
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OBJECT_LIFETIME_FOREVER = 0x0003
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};
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void extendObjectLifetime(int32_t mode);
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//! Flags for onIncStrongAttempted()
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enum {
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FIRST_INC_STRONG = 0x0001
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};
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virtual void onFirstRef();
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virtual void onLastStrongRef(const void* id);
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virtual bool onIncStrongAttempted(uint32_t flags, const void* id);
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virtual void onLastWeakRef(const void* id);
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private:
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friend class weakref_type;
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class weakref_impl;
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RefBase(const RefBase& o);
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RefBase& operator=(const RefBase& o);
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weakref_impl* const mRefs;
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};
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// ---------------------------------------------------------------------------
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template <class T>
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class LightRefBase
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{
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public:
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inline LightRefBase() : mCount(0) { }
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inline void incStrong(const void* id) const {
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android_atomic_inc(&mCount);
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}
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inline void decStrong(const void* id) const {
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if (android_atomic_dec(&mCount) == 1) {
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delete static_cast<const T*>(this);
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}
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}
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//! DEBUGGING ONLY: Get current strong ref count.
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inline int32_t getStrongCount() const {
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return mCount;
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}
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protected:
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inline ~LightRefBase() { }
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private:
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mutable volatile int32_t mCount;
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};
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// ---------------------------------------------------------------------------
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template <typename T>
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class sp
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{
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public:
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typedef typename RefBase::weakref_type weakref_type;
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inline sp() : m_ptr(0) { }
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sp(T* other);
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sp(const sp<T>& other);
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template<typename U> sp(U* other);
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template<typename U> sp(const sp<U>& other);
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~sp();
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// Assignment
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sp& operator = (T* other);
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sp& operator = (const sp<T>& other);
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template<typename U> sp& operator = (const sp<U>& other);
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template<typename U> sp& operator = (U* other);
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//! Special optimization for use by ProcessState (and nobody else).
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void force_set(T* other);
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// Reset
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void clear();
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// Accessors
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inline T& operator* () const { return *m_ptr; }
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inline T* operator-> () const { return m_ptr; }
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inline T* get() const { return m_ptr; }
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// Operators
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COMPARE(==)
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COMPARE(!=)
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COMPARE(>)
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COMPARE(<)
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COMPARE(<=)
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COMPARE(>=)
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private:
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template<typename Y> friend class sp;
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template<typename Y> friend class wp;
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// Optimization for wp::promote().
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sp(T* p, weakref_type* refs);
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T* m_ptr;
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};
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template <typename T>
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TextOutput& operator<<(TextOutput& to, const sp<T>& val);
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// ---------------------------------------------------------------------------
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template <typename T>
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class wp
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{
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public:
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typedef typename RefBase::weakref_type weakref_type;
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inline wp() : m_ptr(0) { }
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wp(T* other);
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wp(const wp<T>& other);
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wp(const sp<T>& other);
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template<typename U> wp(U* other);
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template<typename U> wp(const sp<U>& other);
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template<typename U> wp(const wp<U>& other);
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~wp();
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// Assignment
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wp& operator = (T* other);
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wp& operator = (const wp<T>& other);
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wp& operator = (const sp<T>& other);
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template<typename U> wp& operator = (U* other);
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template<typename U> wp& operator = (const wp<U>& other);
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template<typename U> wp& operator = (const sp<U>& other);
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void set_object_and_refs(T* other, weakref_type* refs);
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// promotion to sp
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sp<T> promote() const;
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// Reset
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void clear();
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// Accessors
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inline weakref_type* get_refs() const { return m_refs; }
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inline T* unsafe_get() const { return m_ptr; }
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// Operators
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COMPARE(==)
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COMPARE(!=)
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COMPARE(>)
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COMPARE(<)
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COMPARE(<=)
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COMPARE(>=)
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private:
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template<typename Y> friend class sp;
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template<typename Y> friend class wp;
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T* m_ptr;
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weakref_type* m_refs;
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};
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template <typename T>
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TextOutput& operator<<(TextOutput& to, const wp<T>& val);
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#undef COMPARE
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// ---------------------------------------------------------------------------
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// No user serviceable parts below here.
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template<typename T>
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sp<T>::sp(T* other)
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: m_ptr(other)
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{
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if (other) other->incStrong(this);
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}
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template<typename T>
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sp<T>::sp(const sp<T>& other)
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: m_ptr(other.m_ptr)
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{
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if (m_ptr) m_ptr->incStrong(this);
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}
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template<typename T> template<typename U>
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sp<T>::sp(U* other) : m_ptr(other)
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{
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if (other) other->incStrong(this);
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}
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template<typename T> template<typename U>
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sp<T>::sp(const sp<U>& other)
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: m_ptr(other.m_ptr)
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{
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if (m_ptr) m_ptr->incStrong(this);
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}
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template<typename T>
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sp<T>::~sp()
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{
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if (m_ptr) m_ptr->decStrong(this);
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}
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template<typename T>
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sp<T>& sp<T>::operator = (const sp<T>& other) {
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T* otherPtr(other.m_ptr);
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if (otherPtr) otherPtr->incStrong(this);
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if (m_ptr) m_ptr->decStrong(this);
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m_ptr = otherPtr;
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return *this;
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}
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template<typename T>
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sp<T>& sp<T>::operator = (T* other)
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{
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if (other) other->incStrong(this);
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if (m_ptr) m_ptr->decStrong(this);
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m_ptr = other;
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return *this;
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}
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template<typename T> template<typename U>
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sp<T>& sp<T>::operator = (const sp<U>& other)
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{
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U* otherPtr(other.m_ptr);
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if (otherPtr) otherPtr->incStrong(this);
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if (m_ptr) m_ptr->decStrong(this);
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m_ptr = otherPtr;
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return *this;
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}
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template<typename T> template<typename U>
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sp<T>& sp<T>::operator = (U* other)
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{
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if (other) other->incStrong(this);
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if (m_ptr) m_ptr->decStrong(this);
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m_ptr = other;
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return *this;
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}
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template<typename T>
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void sp<T>::force_set(T* other)
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{
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other->forceIncStrong(this);
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m_ptr = other;
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}
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template<typename T>
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void sp<T>::clear()
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{
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if (m_ptr) {
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m_ptr->decStrong(this);
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m_ptr = 0;
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}
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}
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template<typename T>
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sp<T>::sp(T* p, weakref_type* refs)
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: m_ptr((p && refs->attemptIncStrong(this)) ? p : 0)
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{
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}
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template <typename T>
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inline TextOutput& operator<<(TextOutput& to, const sp<T>& val)
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{
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to << "sp<>(" << val.get() << ")";
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return to;
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}
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// ---------------------------------------------------------------------------
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template<typename T>
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wp<T>::wp(T* other)
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: m_ptr(other)
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{
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if (other) m_refs = other->createWeak(this);
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}
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template<typename T>
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wp<T>::wp(const wp<T>& other)
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: m_ptr(other.m_ptr), m_refs(other.m_refs)
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{
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if (m_ptr) m_refs->incWeak(this);
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}
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template<typename T>
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wp<T>::wp(const sp<T>& other)
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: m_ptr(other.m_ptr)
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{
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if (m_ptr) {
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m_refs = m_ptr->createWeak(this);
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}
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}
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template<typename T> template<typename U>
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wp<T>::wp(U* other)
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: m_ptr(other)
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{
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if (other) m_refs = other->createWeak(this);
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}
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template<typename T> template<typename U>
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wp<T>::wp(const wp<U>& other)
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: m_ptr(other.m_ptr)
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{
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if (m_ptr) {
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m_refs = other.m_refs;
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m_refs->incWeak(this);
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}
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}
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template<typename T> template<typename U>
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wp<T>::wp(const sp<U>& other)
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: m_ptr(other.m_ptr)
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{
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if (m_ptr) {
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m_refs = m_ptr->createWeak(this);
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}
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}
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template<typename T>
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wp<T>::~wp()
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{
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if (m_ptr) m_refs->decWeak(this);
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}
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template<typename T>
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wp<T>& wp<T>::operator = (T* other)
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{
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weakref_type* newRefs =
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other ? other->createWeak(this) : 0;
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if (m_ptr) m_refs->decWeak(this);
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m_ptr = other;
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m_refs = newRefs;
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return *this;
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}
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template<typename T>
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wp<T>& wp<T>::operator = (const wp<T>& other)
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{
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weakref_type* otherRefs(other.m_refs);
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T* otherPtr(other.m_ptr);
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if (otherPtr) otherRefs->incWeak(this);
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if (m_ptr) m_refs->decWeak(this);
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m_ptr = otherPtr;
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m_refs = otherRefs;
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return *this;
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}
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template<typename T>
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wp<T>& wp<T>::operator = (const sp<T>& other)
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{
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weakref_type* newRefs =
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other != NULL ? other->createWeak(this) : 0;
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T* otherPtr(other.m_ptr);
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if (m_ptr) m_refs->decWeak(this);
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m_ptr = otherPtr;
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m_refs = newRefs;
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return *this;
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}
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template<typename T> template<typename U>
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wp<T>& wp<T>::operator = (U* other)
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{
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weakref_type* newRefs =
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other ? other->createWeak(this) : 0;
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if (m_ptr) m_refs->decWeak(this);
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m_ptr = other;
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m_refs = newRefs;
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return *this;
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}
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template<typename T> template<typename U>
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wp<T>& wp<T>::operator = (const wp<U>& other)
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{
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weakref_type* otherRefs(other.m_refs);
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U* otherPtr(other.m_ptr);
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if (otherPtr) otherRefs->incWeak(this);
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if (m_ptr) m_refs->decWeak(this);
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m_ptr = otherPtr;
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m_refs = otherRefs;
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return *this;
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}
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template<typename T> template<typename U>
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wp<T>& wp<T>::operator = (const sp<U>& other)
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{
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weakref_type* newRefs =
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other != NULL ? other->createWeak(this) : 0;
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U* otherPtr(other.m_ptr);
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if (m_ptr) m_refs->decWeak(this);
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m_ptr = otherPtr;
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m_refs = newRefs;
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return *this;
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}
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template<typename T>
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void wp<T>::set_object_and_refs(T* other, weakref_type* refs)
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{
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if (other) refs->incWeak(this);
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if (m_ptr) m_refs->decWeak(this);
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m_ptr = other;
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m_refs = refs;
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}
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template<typename T>
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sp<T> wp<T>::promote() const
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{
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return sp<T>(m_ptr, m_refs);
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}
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template<typename T>
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void wp<T>::clear()
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{
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if (m_ptr) {
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m_refs->decWeak(this);
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m_ptr = 0;
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}
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}
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template <typename T>
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inline TextOutput& operator<<(TextOutput& to, const wp<T>& val)
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{
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to << "wp<>(" << val.unsafe_get() << ")";
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return to;
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}
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}; // namespace android
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// ---------------------------------------------------------------------------
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#endif // ANDROID_REF_BASE_H
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