michael@0: /*
michael@0:  * Copyright (C) 2005 The Android Open Source Project
michael@0:  *
michael@0:  * Licensed under the Apache License, Version 2.0 (the "License");
michael@0:  * you may not use this file except in compliance with the License.
michael@0:  * You may obtain a copy of the License at
michael@0:  *
michael@0:  *      http://www.apache.org/licenses/LICENSE-2.0
michael@0:  *
michael@0:  * Unless required by applicable law or agreed to in writing, software
michael@0:  * distributed under the License is distributed on an "AS IS" BASIS,
michael@0:  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
michael@0:  * See the License for the specific language governing permissions and
michael@0:  * limitations under the License.
michael@0:  */
michael@0: 
michael@0: #ifndef ANDROID_REF_BASE_H
michael@0: #define ANDROID_REF_BASE_H
michael@0: 
michael@0: #include <cutils/atomic.h>
michael@0: 
michael@0: #include <stdint.h>
michael@0: #include <sys/types.h>
michael@0: #include <stdlib.h>
michael@0: #include <string.h>
michael@0: 
michael@0: #include <utils/StrongPointer.h>
michael@0: 
michael@0: // ---------------------------------------------------------------------------
michael@0: namespace android {
michael@0: 
michael@0: class TextOutput;
michael@0: TextOutput& printWeakPointer(TextOutput& to, const void* val);
michael@0: 
michael@0: // ---------------------------------------------------------------------------
michael@0: 
michael@0: #define COMPARE_WEAK(_op_)                                      \
michael@0: inline bool operator _op_ (const sp<T>& o) const {              \
michael@0:     return m_ptr _op_ o.m_ptr;                                  \
michael@0: }                                                               \
michael@0: inline bool operator _op_ (const T* o) const {                  \
michael@0:     return m_ptr _op_ o;                                        \
michael@0: }                                                               \
michael@0: template<typename U>                                            \
michael@0: inline bool operator _op_ (const sp<U>& o) const {              \
michael@0:     return m_ptr _op_ o.m_ptr;                                  \
michael@0: }                                                               \
michael@0: template<typename U>                                            \
michael@0: inline bool operator _op_ (const U* o) const {                  \
michael@0:     return m_ptr _op_ o;                                        \
michael@0: }
michael@0: 
michael@0: // ---------------------------------------------------------------------------
michael@0: class ReferenceMover;
michael@0: class ReferenceConverterBase {
michael@0: public:
michael@0:     virtual size_t getReferenceTypeSize() const = 0;
michael@0:     virtual void* getReferenceBase(void const*) const = 0;
michael@0:     inline virtual ~ReferenceConverterBase() { }
michael@0: };
michael@0: 
michael@0: // ---------------------------------------------------------------------------
michael@0: 
michael@0: class RefBase
michael@0: {
michael@0: public:
michael@0:             void            incStrong(const void* id) const;
michael@0:             void            decStrong(const void* id) const;
michael@0:     
michael@0:             void            forceIncStrong(const void* id) const;
michael@0: 
michael@0:             //! DEBUGGING ONLY: Get current strong ref count.
michael@0:             int32_t         getStrongCount() const;
michael@0: 
michael@0:     class weakref_type
michael@0:     {
michael@0:     public:
michael@0:         RefBase*            refBase() const;
michael@0:         
michael@0:         void                incWeak(const void* id);
michael@0:         void                decWeak(const void* id);
michael@0:         
michael@0:         // acquires a strong reference if there is already one.
michael@0:         bool                attemptIncStrong(const void* id);
michael@0:         
michael@0:         // acquires a weak reference if there is already one.
michael@0:         // This is not always safe. see ProcessState.cpp and BpBinder.cpp
michael@0:         // for proper use.
michael@0:         bool                attemptIncWeak(const void* id);
michael@0: 
michael@0:         //! DEBUGGING ONLY: Get current weak ref count.
michael@0:         int32_t             getWeakCount() const;
michael@0: 
michael@0:         //! DEBUGGING ONLY: Print references held on object.
michael@0:         void                printRefs() const;
michael@0: 
michael@0:         //! DEBUGGING ONLY: Enable tracking for this object.
michael@0:         // enable -- enable/disable tracking
michael@0:         // retain -- when tracking is enable, if true, then we save a stack trace
michael@0:         //           for each reference and dereference; when retain == false, we
michael@0:         //           match up references and dereferences and keep only the 
michael@0:         //           outstanding ones.
michael@0:         
michael@0:         void                trackMe(bool enable, bool retain);
michael@0:     };
michael@0:     
michael@0:             weakref_type*   createWeak(const void* id) const;
michael@0:             
michael@0:             weakref_type*   getWeakRefs() const;
michael@0: 
michael@0:             //! DEBUGGING ONLY: Print references held on object.
michael@0:     inline  void            printRefs() const { getWeakRefs()->printRefs(); }
michael@0: 
michael@0:             //! DEBUGGING ONLY: Enable tracking of object.
michael@0:     inline  void            trackMe(bool enable, bool retain)
michael@0:     { 
michael@0:         getWeakRefs()->trackMe(enable, retain); 
michael@0:     }
michael@0: 
michael@0:     typedef RefBase basetype;
michael@0: 
michael@0: protected:
michael@0:                             RefBase();
michael@0:     virtual                 ~RefBase();
michael@0: 
michael@0:     //! Flags for extendObjectLifetime()
michael@0:     enum {
michael@0:         OBJECT_LIFETIME_STRONG  = 0x0000,
michael@0:         OBJECT_LIFETIME_WEAK    = 0x0001,
michael@0:         OBJECT_LIFETIME_MASK    = 0x0001
michael@0:     };
michael@0:     
michael@0:             void            extendObjectLifetime(int32_t mode);
michael@0:             
michael@0:     //! Flags for onIncStrongAttempted()
michael@0:     enum {
michael@0:         FIRST_INC_STRONG = 0x0001
michael@0:     };
michael@0:     
michael@0:     virtual void            onFirstRef();
michael@0:     virtual void            onLastStrongRef(const void* id);
michael@0:     virtual bool            onIncStrongAttempted(uint32_t flags, const void* id);
michael@0:     virtual void            onLastWeakRef(const void* id);
michael@0: 
michael@0: private:
michael@0:     friend class ReferenceMover;
michael@0:     static void moveReferences(void* d, void const* s, size_t n,
michael@0:             const ReferenceConverterBase& caster);
michael@0: 
michael@0: private:
michael@0:     friend class weakref_type;
michael@0:     class weakref_impl;
michael@0:     
michael@0:                             RefBase(const RefBase& o);
michael@0:             RefBase&        operator=(const RefBase& o);
michael@0: 
michael@0:         weakref_impl* const mRefs;
michael@0: };
michael@0: 
michael@0: // ---------------------------------------------------------------------------
michael@0: 
michael@0: template <class T>
michael@0: class LightRefBase
michael@0: {
michael@0: public:
michael@0:     inline LightRefBase() : mCount(0) { }
michael@0:     inline void incStrong(const void* id) const {
michael@0:         android_atomic_inc(&mCount);
michael@0:     }
michael@0:     inline void decStrong(const void* id) const {
michael@0:         if (android_atomic_dec(&mCount) == 1) {
michael@0:             delete static_cast<const T*>(this);
michael@0:         }
michael@0:     }
michael@0:     //! DEBUGGING ONLY: Get current strong ref count.
michael@0:     inline int32_t getStrongCount() const {
michael@0:         return mCount;
michael@0:     }
michael@0: 
michael@0:     typedef LightRefBase<T> basetype;
michael@0: 
michael@0: protected:
michael@0:     inline ~LightRefBase() { }
michael@0: 
michael@0: private:
michael@0:     friend class ReferenceMover;
michael@0:     inline static void moveReferences(void* d, void const* s, size_t n,
michael@0:             const ReferenceConverterBase& caster) { }
michael@0: 
michael@0: private:
michael@0:     mutable volatile int32_t mCount;
michael@0: };
michael@0: 
michael@0: // ---------------------------------------------------------------------------
michael@0: 
michael@0: template <typename T>
michael@0: class wp
michael@0: {
michael@0: public:
michael@0:     typedef typename RefBase::weakref_type weakref_type;
michael@0:     
michael@0:     inline wp() : m_ptr(0) { }
michael@0: 
michael@0:     wp(T* other);
michael@0:     wp(const wp<T>& other);
michael@0:     wp(const sp<T>& other);
michael@0:     template<typename U> wp(U* other);
michael@0:     template<typename U> wp(const sp<U>& other);
michael@0:     template<typename U> wp(const wp<U>& other);
michael@0: 
michael@0:     ~wp();
michael@0:     
michael@0:     // Assignment
michael@0: 
michael@0:     wp& operator = (T* other);
michael@0:     wp& operator = (const wp<T>& other);
michael@0:     wp& operator = (const sp<T>& other);
michael@0:     
michael@0:     template<typename U> wp& operator = (U* other);
michael@0:     template<typename U> wp& operator = (const wp<U>& other);
michael@0:     template<typename U> wp& operator = (const sp<U>& other);
michael@0:     
michael@0:     void set_object_and_refs(T* other, weakref_type* refs);
michael@0: 
michael@0:     // promotion to sp
michael@0:     
michael@0:     sp<T> promote() const;
michael@0: 
michael@0:     // Reset
michael@0:     
michael@0:     void clear();
michael@0: 
michael@0:     // Accessors
michael@0:     
michael@0:     inline  weakref_type* get_refs() const { return m_refs; }
michael@0:     
michael@0:     inline  T* unsafe_get() const { return m_ptr; }
michael@0: 
michael@0:     // Operators
michael@0: 
michael@0:     COMPARE_WEAK(==)
michael@0:     COMPARE_WEAK(!=)
michael@0:     COMPARE_WEAK(>)
michael@0:     COMPARE_WEAK(<)
michael@0:     COMPARE_WEAK(<=)
michael@0:     COMPARE_WEAK(>=)
michael@0: 
michael@0:     inline bool operator == (const wp<T>& o) const {
michael@0:         return (m_ptr == o.m_ptr) && (m_refs == o.m_refs);
michael@0:     }
michael@0:     template<typename U>
michael@0:     inline bool operator == (const wp<U>& o) const {
michael@0:         return m_ptr == o.m_ptr;
michael@0:     }
michael@0: 
michael@0:     inline bool operator > (const wp<T>& o) const {
michael@0:         return (m_ptr == o.m_ptr) ? (m_refs > o.m_refs) : (m_ptr > o.m_ptr);
michael@0:     }
michael@0:     template<typename U>
michael@0:     inline bool operator > (const wp<U>& o) const {
michael@0:         return (m_ptr == o.m_ptr) ? (m_refs > o.m_refs) : (m_ptr > o.m_ptr);
michael@0:     }
michael@0: 
michael@0:     inline bool operator < (const wp<T>& o) const {
michael@0:         return (m_ptr == o.m_ptr) ? (m_refs < o.m_refs) : (m_ptr < o.m_ptr);
michael@0:     }
michael@0:     template<typename U>
michael@0:     inline bool operator < (const wp<U>& o) const {
michael@0:         return (m_ptr == o.m_ptr) ? (m_refs < o.m_refs) : (m_ptr < o.m_ptr);
michael@0:     }
michael@0:                          inline bool operator != (const wp<T>& o) const { return m_refs != o.m_refs; }
michael@0:     template<typename U> inline bool operator != (const wp<U>& o) const { return !operator == (o); }
michael@0:                          inline bool operator <= (const wp<T>& o) const { return !operator > (o); }
michael@0:     template<typename U> inline bool operator <= (const wp<U>& o) const { return !operator > (o); }
michael@0:                          inline bool operator >= (const wp<T>& o) const { return !operator < (o); }
michael@0:     template<typename U> inline bool operator >= (const wp<U>& o) const { return !operator < (o); }
michael@0: 
michael@0: private:
michael@0:     template<typename Y> friend class sp;
michael@0:     template<typename Y> friend class wp;
michael@0: 
michael@0:     T*              m_ptr;
michael@0:     weakref_type*   m_refs;
michael@0: };
michael@0: 
michael@0: template <typename T>
michael@0: TextOutput& operator<<(TextOutput& to, const wp<T>& val);
michael@0: 
michael@0: #undef COMPARE_WEAK
michael@0: 
michael@0: // ---------------------------------------------------------------------------
michael@0: // No user serviceable parts below here.
michael@0: 
michael@0: template<typename T>
michael@0: wp<T>::wp(T* other)
michael@0:     : m_ptr(other)
michael@0: {
michael@0:     if (other) m_refs = other->createWeak(this);
michael@0: }
michael@0: 
michael@0: template<typename T>
michael@0: wp<T>::wp(const wp<T>& other)
michael@0:     : m_ptr(other.m_ptr), m_refs(other.m_refs)
michael@0: {
michael@0:     if (m_ptr) m_refs->incWeak(this);
michael@0: }
michael@0: 
michael@0: template<typename T>
michael@0: wp<T>::wp(const sp<T>& other)
michael@0:     : m_ptr(other.m_ptr)
michael@0: {
michael@0:     if (m_ptr) {
michael@0:         m_refs = m_ptr->createWeak(this);
michael@0:     }
michael@0: }
michael@0: 
michael@0: template<typename T> template<typename U>
michael@0: wp<T>::wp(U* other)
michael@0:     : m_ptr(other)
michael@0: {
michael@0:     if (other) m_refs = other->createWeak(this);
michael@0: }
michael@0: 
michael@0: template<typename T> template<typename U>
michael@0: wp<T>::wp(const wp<U>& other)
michael@0:     : m_ptr(other.m_ptr)
michael@0: {
michael@0:     if (m_ptr) {
michael@0:         m_refs = other.m_refs;
michael@0:         m_refs->incWeak(this);
michael@0:     }
michael@0: }
michael@0: 
michael@0: template<typename T> template<typename U>
michael@0: wp<T>::wp(const sp<U>& other)
michael@0:     : m_ptr(other.m_ptr)
michael@0: {
michael@0:     if (m_ptr) {
michael@0:         m_refs = m_ptr->createWeak(this);
michael@0:     }
michael@0: }
michael@0: 
michael@0: template<typename T>
michael@0: wp<T>::~wp()
michael@0: {
michael@0:     if (m_ptr) m_refs->decWeak(this);
michael@0: }
michael@0: 
michael@0: template<typename T>
michael@0: wp<T>& wp<T>::operator = (T* other)
michael@0: {
michael@0:     weakref_type* newRefs =
michael@0:         other ? other->createWeak(this) : 0;
michael@0:     if (m_ptr) m_refs->decWeak(this);
michael@0:     m_ptr = other;
michael@0:     m_refs = newRefs;
michael@0:     return *this;
michael@0: }
michael@0: 
michael@0: template<typename T>
michael@0: wp<T>& wp<T>::operator = (const wp<T>& other)
michael@0: {
michael@0:     weakref_type* otherRefs(other.m_refs);
michael@0:     T* otherPtr(other.m_ptr);
michael@0:     if (otherPtr) otherRefs->incWeak(this);
michael@0:     if (m_ptr) m_refs->decWeak(this);
michael@0:     m_ptr = otherPtr;
michael@0:     m_refs = otherRefs;
michael@0:     return *this;
michael@0: }
michael@0: 
michael@0: template<typename T>
michael@0: wp<T>& wp<T>::operator = (const sp<T>& other)
michael@0: {
michael@0:     weakref_type* newRefs =
michael@0:         other != NULL ? other->createWeak(this) : 0;
michael@0:     T* otherPtr(other.m_ptr);
michael@0:     if (m_ptr) m_refs->decWeak(this);
michael@0:     m_ptr = otherPtr;
michael@0:     m_refs = newRefs;
michael@0:     return *this;
michael@0: }
michael@0: 
michael@0: template<typename T> template<typename U>
michael@0: wp<T>& wp<T>::operator = (U* other)
michael@0: {
michael@0:     weakref_type* newRefs =
michael@0:         other ? other->createWeak(this) : 0;
michael@0:     if (m_ptr) m_refs->decWeak(this);
michael@0:     m_ptr = other;
michael@0:     m_refs = newRefs;
michael@0:     return *this;
michael@0: }
michael@0: 
michael@0: template<typename T> template<typename U>
michael@0: wp<T>& wp<T>::operator = (const wp<U>& other)
michael@0: {
michael@0:     weakref_type* otherRefs(other.m_refs);
michael@0:     U* otherPtr(other.m_ptr);
michael@0:     if (otherPtr) otherRefs->incWeak(this);
michael@0:     if (m_ptr) m_refs->decWeak(this);
michael@0:     m_ptr = otherPtr;
michael@0:     m_refs = otherRefs;
michael@0:     return *this;
michael@0: }
michael@0: 
michael@0: template<typename T> template<typename U>
michael@0: wp<T>& wp<T>::operator = (const sp<U>& other)
michael@0: {
michael@0:     weakref_type* newRefs =
michael@0:         other != NULL ? other->createWeak(this) : 0;
michael@0:     U* otherPtr(other.m_ptr);
michael@0:     if (m_ptr) m_refs->decWeak(this);
michael@0:     m_ptr = otherPtr;
michael@0:     m_refs = newRefs;
michael@0:     return *this;
michael@0: }
michael@0: 
michael@0: template<typename T>
michael@0: void wp<T>::set_object_and_refs(T* other, weakref_type* refs)
michael@0: {
michael@0:     if (other) refs->incWeak(this);
michael@0:     if (m_ptr) m_refs->decWeak(this);
michael@0:     m_ptr = other;
michael@0:     m_refs = refs;
michael@0: }
michael@0: 
michael@0: template<typename T>
michael@0: sp<T> wp<T>::promote() const
michael@0: {
michael@0:     sp<T> result;
michael@0:     if (m_ptr && m_refs->attemptIncStrong(&result)) {
michael@0:         result.set_pointer(m_ptr);
michael@0:     }
michael@0:     return result;
michael@0: }
michael@0: 
michael@0: template<typename T>
michael@0: void wp<T>::clear()
michael@0: {
michael@0:     if (m_ptr) {
michael@0:         m_refs->decWeak(this);
michael@0:         m_ptr = 0;
michael@0:     }
michael@0: }
michael@0: 
michael@0: template <typename T>
michael@0: inline TextOutput& operator<<(TextOutput& to, const wp<T>& val)
michael@0: {
michael@0:     return printWeakPointer(to, val.unsafe_get());
michael@0: }
michael@0: 
michael@0: // ---------------------------------------------------------------------------
michael@0: 
michael@0: // this class just serves as a namespace so TYPE::moveReferences can stay
michael@0: // private.
michael@0: 
michael@0: class ReferenceMover {
michael@0:     // StrongReferenceCast and WeakReferenceCast do the impedance matching
michael@0:     // between the generic (void*) implementation in Refbase and the strongly typed
michael@0:     // template specializations below.
michael@0: 
michael@0:     template <typename TYPE>
michael@0:     struct StrongReferenceCast : public ReferenceConverterBase {
michael@0:         virtual size_t getReferenceTypeSize() const { return sizeof( sp<TYPE> ); }
michael@0:         virtual void* getReferenceBase(void const* p) const {
michael@0:             sp<TYPE> const* sptr(reinterpret_cast<sp<TYPE> const*>(p));
michael@0:             return static_cast<typename TYPE::basetype *>(sptr->get());
michael@0:         }
michael@0:     };
michael@0: 
michael@0:     template <typename TYPE>
michael@0:     struct WeakReferenceCast : public ReferenceConverterBase {
michael@0:         virtual size_t getReferenceTypeSize() const { return sizeof( wp<TYPE> ); }
michael@0:         virtual void* getReferenceBase(void const* p) const {
michael@0:             wp<TYPE> const* sptr(reinterpret_cast<wp<TYPE> const*>(p));
michael@0:             return static_cast<typename TYPE::basetype *>(sptr->unsafe_get());
michael@0:         }
michael@0:     };
michael@0: 
michael@0: public:
michael@0:     template<typename TYPE> static inline
michael@0:     void move_references(sp<TYPE>* d, sp<TYPE> const* s, size_t n) {
michael@0:         memmove(d, s, n*sizeof(sp<TYPE>));
michael@0:         StrongReferenceCast<TYPE> caster;
michael@0:         TYPE::moveReferences(d, s, n, caster);
michael@0:     }
michael@0:     template<typename TYPE> static inline
michael@0:     void move_references(wp<TYPE>* d, wp<TYPE> const* s, size_t n) {
michael@0:         memmove(d, s, n*sizeof(wp<TYPE>));
michael@0:         WeakReferenceCast<TYPE> caster;
michael@0:         TYPE::moveReferences(d, s, n, caster);
michael@0:     }
michael@0: };
michael@0: 
michael@0: // specialization for moving sp<> and wp<> types.
michael@0: // these are used by the [Sorted|Keyed]Vector<> implementations
michael@0: // sp<> and wp<> need to be handled specially, because they do not
michael@0: // have trivial copy operation in the general case (see RefBase.cpp
michael@0: // when DEBUG ops are enabled), but can be implemented very
michael@0: // efficiently in most cases.
michael@0: 
michael@0: template<typename TYPE> inline
michael@0: void move_forward_type(sp<TYPE>* d, sp<TYPE> const* s, size_t n) {
michael@0:     ReferenceMover::move_references(d, s, n);
michael@0: }
michael@0: 
michael@0: template<typename TYPE> inline
michael@0: void move_backward_type(sp<TYPE>* d, sp<TYPE> const* s, size_t n) {
michael@0:     ReferenceMover::move_references(d, s, n);
michael@0: }
michael@0: 
michael@0: template<typename TYPE> inline
michael@0: void move_forward_type(wp<TYPE>* d, wp<TYPE> const* s, size_t n) {
michael@0:     ReferenceMover::move_references(d, s, n);
michael@0: }
michael@0: 
michael@0: template<typename TYPE> inline
michael@0: void move_backward_type(wp<TYPE>* d, wp<TYPE> const* s, size_t n) {
michael@0:     ReferenceMover::move_references(d, s, n);
michael@0: }
michael@0: 
michael@0: 
michael@0: }; // namespace android
michael@0: 
michael@0: // ---------------------------------------------------------------------------
michael@0: 
michael@0: #endif // ANDROID_REF_BASE_H