| /* | 
 |  * 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> | 
 | #include <utils/TypeHelpers.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 ReferenceRenamer { | 
 | protected: | 
 |     // destructor is purposedly not virtual so we avoid code overhead from | 
 |     // subclasses; we have to make it protected to guarantee that it | 
 |     // cannot be called from this base class (and to make strict compilers | 
 |     // happy). | 
 |     ~ReferenceRenamer() { } | 
 | public: | 
 |     virtual void operator()(size_t i) const = 0; | 
 | }; | 
 |  | 
 | // --------------------------------------------------------------------------- | 
 |  | 
 | 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 weakref_type; | 
 |     class weakref_impl; | 
 |      | 
 |                             RefBase(const RefBase& o); | 
 |             RefBase&        operator=(const RefBase& o); | 
 |  | 
 | private: | 
 |     friend class ReferenceMover; | 
 |  | 
 |     static void renameRefs(size_t n, const ReferenceRenamer& renamer); | 
 |  | 
 |     static void renameRefId(weakref_type* ref, | 
 |             const void* old_id, const void* new_id); | 
 |  | 
 |     static void renameRefId(RefBase* ref, | 
 |             const void* old_id, const void* new_id); | 
 |  | 
 |         weakref_impl* const mRefs; | 
 | }; | 
 |  | 
 | // --------------------------------------------------------------------------- | 
 |  | 
 | template <class T> | 
 | class LightRefBase | 
 | { | 
 | public: | 
 |     inline LightRefBase() : mCount(0) { } | 
 |     inline void incStrong(__attribute__((unused)) const void* id) const { | 
 |         android_atomic_inc(&mCount); | 
 |     } | 
 |     inline void decStrong(__attribute__((unused)) 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 renameRefs(size_t n, const ReferenceRenamer& renamer) { } | 
 |     inline static void renameRefId(T* ref, | 
 |             const void* old_id, const void* new_id) { } | 
 |  | 
 | private: | 
 |     mutable volatile int32_t mCount; | 
 | }; | 
 |  | 
 | // This is a wrapper around LightRefBase that simply enforces a virtual | 
 | // destructor to eliminate the template requirement of LightRefBase | 
 | class VirtualLightRefBase : public LightRefBase<VirtualLightRefBase> { | 
 | public: | 
 |     virtual ~VirtualLightRefBase() {} | 
 | }; | 
 |  | 
 | // --------------------------------------------------------------------------- | 
 |  | 
 | 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 { | 
 | public: | 
 |     // it would be nice if we could make sure no extra code is generated | 
 |     // for sp<TYPE> or wp<TYPE> when TYPE is a descendant of RefBase: | 
 |     // Using a sp<RefBase> override doesn't work; it's a bit like we wanted | 
 |     // a template<typename TYPE inherits RefBase> template... | 
 |  | 
 |     template<typename TYPE> static inline | 
 |     void move_references(sp<TYPE>* d, sp<TYPE> const* s, size_t n) { | 
 |  | 
 |         class Renamer : public ReferenceRenamer { | 
 |             sp<TYPE>* d; | 
 |             sp<TYPE> const* s; | 
 |             virtual void operator()(size_t i) const { | 
 |                 // The id are known to be the sp<>'s this pointer | 
 |                 TYPE::renameRefId(d[i].get(), &s[i], &d[i]); | 
 |             } | 
 |         public: | 
 |             Renamer(sp<TYPE>* d, sp<TYPE> const* s) : d(d), s(s) { } | 
 |             virtual ~Renamer() { } | 
 |         }; | 
 |  | 
 |         memmove(d, s, n*sizeof(sp<TYPE>)); | 
 |         TYPE::renameRefs(n, Renamer(d, s)); | 
 |     } | 
 |  | 
 |  | 
 |     template<typename TYPE> static inline | 
 |     void move_references(wp<TYPE>* d, wp<TYPE> const* s, size_t n) { | 
 |  | 
 |         class Renamer : public ReferenceRenamer { | 
 |             wp<TYPE>* d; | 
 |             wp<TYPE> const* s; | 
 |             virtual void operator()(size_t i) const { | 
 |                 // The id are known to be the wp<>'s this pointer | 
 |                 TYPE::renameRefId(d[i].get_refs(), &s[i], &d[i]); | 
 |             } | 
 |         public: | 
 |             Renamer(wp<TYPE>* d, wp<TYPE> const* s) : d(d), s(s) { } | 
 |             virtual ~Renamer() { } | 
 |         }; | 
 |  | 
 |         memmove(d, s, n*sizeof(wp<TYPE>)); | 
 |         TYPE::renameRefs(n, Renamer(d, s)); | 
 |     } | 
 | }; | 
 |  | 
 | // 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 |