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platform_system_core/include/utils/RefBase.h
Mathias Agopian ff49de731f fix [3408713] Dialog window invisible sometimes 
weak pointer comparison operators were implemented wrong,
they were using the internal "unsafe" pointer. We could end up
with two "equal" weak pointer pointing to different objects.

this caused KeyedVector keyed by weak pointer to work incorrectly, in
turn causing a window that just got added to a list to be immediately
removed.

Change-Id: Ib191010c39aafa9229109e4211f6c3b2b2f9696d
2013-07-30 13:56:55 -07:00

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