include/utils/RefBase.h - platform/frameworks/base - Gitiles

 /*
  * 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 <stdint.h>
 #include <sys/types.h>
 #include <stdlib.h>
 #include <string.h>

 #include <utils/StrongPointer.h>

 // ---------------------------------------------------------------------------
 namespace android {

 class TextOutput;
 TextOutput& printWeakPointer(TextOutput& to, const void* val);

 // ---------------------------------------------------------------------------

 #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;                                        \
 }

 // ---------------------------------------------------------------------------
 class ReferenceMover;
 class ReferenceConverterBase {
 public:
     virtual size_t getReferenceTypeSize() const = 0;
     virtual void* getReferenceBase(void const*) const = 0;
     inline virtual ~ReferenceConverterBase() { }
 };

 // ---------------------------------------------------------------------------

 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);

         // acquires a strong reference if there is already one.
         bool                attemptIncStrong(const void* id);

         // acquires a weak reference if there is already one.
         // This is not always safe. see ProcessState.cpp and BpBinder.cpp
         // for proper use.
         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);
     }

     typedef RefBase basetype;

 protected:
                             RefBase();
     virtual                 ~RefBase();

     //! Flags for extendObjectLifetime()
     enum {
         OBJECT_LIFETIME_STRONG  = 0x0000,
         OBJECT_LIFETIME_WEAK    = 0x0001,
         OBJECT_LIFETIME_MASK    = 0x0001
     };

             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 ReferenceMover;
     static void moveReferences(void* d, void const* s, size_t n,
             const ReferenceConverterBase& caster);

 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;
     }

     typedef LightRefBase<T> basetype;

 protected:
     inline ~LightRefBase() { }

 private:
     friend class ReferenceMover;
     inline static void moveReferences(void* d, void const* s, size_t n,
             const ReferenceConverterBase& caster) { }

 private:
     mutable volatile int32_t mCount;
 };

 // ---------------------------------------------------------------------------

 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_WEAK

 // ---------------------------------------------------------------------------
 // No user serviceable parts below here.

 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
 {
     sp<T> result;
     if (m_ptr && m_refs->attemptIncStrong(&result)) {
         result.set_pointer(m_ptr);
     }
     return result;
 }

 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)
 {
     return printWeakPointer(to, val.unsafe_get());
 }

 // ---------------------------------------------------------------------------

 // this class just serves as a namespace so TYPE::moveReferences can stay
 // private.

 class ReferenceMover {
     // StrongReferenceCast and WeakReferenceCast do the impedance matching
     // between the generic (void*) implementation in Refbase and the strongly typed
     // template specializations below.

     template <typename TYPE>
     struct StrongReferenceCast : public ReferenceConverterBase {
         virtual size_t getReferenceTypeSize() const { return sizeof( sp<TYPE> ); }
         virtual void* getReferenceBase(void const* p) const {
             sp<TYPE> const* sptr(reinterpret_cast<sp<TYPE> const*>(p));
             return static_cast<typename TYPE::basetype *>(sptr->get());
         }
     };

     template <typename TYPE>
     struct WeakReferenceCast : public ReferenceConverterBase {
         virtual size_t getReferenceTypeSize() const { return sizeof( wp<TYPE> ); }
         virtual void* getReferenceBase(void const* p) const {
             wp<TYPE> const* sptr(reinterpret_cast<wp<TYPE> const*>(p));
             return static_cast<typename TYPE::basetype *>(sptr->unsafe_get());
         }
     };

 public:
     template<typename TYPE> static inline
     void move_references(sp<TYPE>* d, sp<TYPE> const* s, size_t n) {
         memmove(d, s, n*sizeof(sp<TYPE>));
         StrongReferenceCast<TYPE> caster;
         TYPE::moveReferences(d, s, n, caster);
     }
     template<typename TYPE> static inline
     void move_references(wp<TYPE>* d, wp<TYPE> const* s, size_t n) {
         memmove(d, s, n*sizeof(wp<TYPE>));
         WeakReferenceCast<TYPE> caster;
         TYPE::moveReferences(d, s, n, caster);
     }
 };

 // specialization for moving sp<> and wp<> types.
 // these are used by the [Sorted|Keyed]Vector<> implementations
 // sp<> and wp<> need to be handled specially, because they do not
 // have trivial copy operation in the general case (see RefBase.cpp
 // when DEBUG ops are enabled), but can be implemented very
 // efficiently in most cases.

 template<typename TYPE> inline
 void move_forward_type(sp<TYPE>* d, sp<TYPE> const* s, size_t n) {
     ReferenceMover::move_references(d, s, n);
 }

 template<typename TYPE> inline
 void move_backward_type(sp<TYPE>* d, sp<TYPE> const* s, size_t n) {
     ReferenceMover::move_references(d, s, n);
 }

 template<typename TYPE> inline
 void move_forward_type(wp<TYPE>* d, wp<TYPE> const* s, size_t n) {
     ReferenceMover::move_references(d, s, n);
 }

 template<typename TYPE> inline
 void move_backward_type(wp<TYPE>* d, wp<TYPE> const* s, size_t n) {
     ReferenceMover::move_references(d, s, n);
 }


 }; // namespace android

 // ---------------------------------------------------------------------------

 #endif // ANDROID_REF_BASE_H
	/*
	* 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 <stdint.h>
	#include <sys/types.h>
	#include <stdlib.h>
	#include <string.h>

	#include <utils/StrongPointer.h>

	// ---------------------------------------------------------------------------
	namespace android {

	class TextOutput;
	TextOutput& printWeakPointer(TextOutput& to, const void* val);

	// ---------------------------------------------------------------------------

	#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; \
	}

	// ---------------------------------------------------------------------------
	class ReferenceMover;
	class ReferenceConverterBase {
	public:
	virtual size_t getReferenceTypeSize() const = 0;
	virtual void* getReferenceBase(void const*) const = 0;
	inline virtual ~ReferenceConverterBase() { }
	};

	// ---------------------------------------------------------------------------

	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);

	// acquires a strong reference if there is already one.
	bool attemptIncStrong(const void* id);

	// acquires a weak reference if there is already one.
	// This is not always safe. see ProcessState.cpp and BpBinder.cpp
	// for proper use.
	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);
	}

	typedef RefBase basetype;

	protected:
	RefBase();
	virtual ~RefBase();

	//! Flags for extendObjectLifetime()
	enum {
	OBJECT_LIFETIME_STRONG = 0x0000,
	OBJECT_LIFETIME_WEAK = 0x0001,
	OBJECT_LIFETIME_MASK = 0x0001
	};

	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 ReferenceMover;
	static void moveReferences(void* d, void const* s, size_t n,
	const ReferenceConverterBase& caster);

	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;
	}

	typedef LightRefBase<T> basetype;

	protected:
	inline ~LightRefBase() { }

	private:
	friend class ReferenceMover;
	inline static void moveReferences(void* d, void const* s, size_t n,
	const ReferenceConverterBase& caster) { }

	private:
	mutable volatile int32_t mCount;
	};

	// ---------------------------------------------------------------------------

	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_WEAK

	// ---------------------------------------------------------------------------
	// No user serviceable parts below here.

	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
	{
	sp<T> result;
	if (m_ptr && m_refs->attemptIncStrong(&result)) {
	result.set_pointer(m_ptr);
	}
	return result;
	}

	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)
	{
	return printWeakPointer(to, val.unsafe_get());
	}

	// ---------------------------------------------------------------------------

	// this class just serves as a namespace so TYPE::moveReferences can stay
	// private.

	class ReferenceMover {
	// StrongReferenceCast and WeakReferenceCast do the impedance matching
	// between the generic (void*) implementation in Refbase and the strongly typed
	// template specializations below.

	template <typename TYPE>
	struct StrongReferenceCast : public ReferenceConverterBase {
	virtual size_t getReferenceTypeSize() const { return sizeof( sp<TYPE> ); }
	virtual void* getReferenceBase(void const* p) const {
	sp<TYPE> const* sptr(reinterpret_cast<sp<TYPE> const*>(p));
	return static_cast<typename TYPE::basetype *>(sptr->get());
	}
	};

	template <typename TYPE>
	struct WeakReferenceCast : public ReferenceConverterBase {
	virtual size_t getReferenceTypeSize() const { return sizeof( wp<TYPE> ); }
	virtual void* getReferenceBase(void const* p) const {
	wp<TYPE> const* sptr(reinterpret_cast<wp<TYPE> const*>(p));
	return static_cast<typename TYPE::basetype *>(sptr->unsafe_get());
	}
	};

	public:
	template<typename TYPE> static inline
	void move_references(sp<TYPE>* d, sp<TYPE> const* s, size_t n) {
	memmove(d, s, n*sizeof(sp<TYPE>));
	StrongReferenceCast<TYPE> caster;
	TYPE::moveReferences(d, s, n, caster);
	}
	template<typename TYPE> static inline
	void move_references(wp<TYPE>* d, wp<TYPE> const* s, size_t n) {
	memmove(d, s, n*sizeof(wp<TYPE>));
	WeakReferenceCast<TYPE> caster;
	TYPE::moveReferences(d, s, n, caster);
	}
	};

	// specialization for moving sp<> and wp<> types.
	// these are used by the [Sorted\|Keyed]Vector<> implementations
	// sp<> and wp<> need to be handled specially, because they do not
	// have trivial copy operation in the general case (see RefBase.cpp
	// when DEBUG ops are enabled), but can be implemented very
	// efficiently in most cases.

	template<typename TYPE> inline
	void move_forward_type(sp<TYPE>* d, sp<TYPE> const* s, size_t n) {
	ReferenceMover::move_references(d, s, n);
	}

	template<typename TYPE> inline
	void move_backward_type(sp<TYPE>* d, sp<TYPE> const* s, size_t n) {
	ReferenceMover::move_references(d, s, n);
	}

	template<typename TYPE> inline
	void move_forward_type(wp<TYPE>* d, wp<TYPE> const* s, size_t n) {
	ReferenceMover::move_references(d, s, n);
	}

	template<typename TYPE> inline
	void move_backward_type(wp<TYPE>* d, wp<TYPE> const* s, size_t n) {
	ReferenceMover::move_references(d, s, n);
	}


	}; // namespace android

	// ---------------------------------------------------------------------------

	#endif // ANDROID_REF_BASE_H