libs/utils/RefBase.cpp - 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.
  */

 #define LOG_TAG "RefBase"

 #include <utils/RefBase.h>

 #include <utils/Atomic.h>
 #include <utils/CallStack.h>
 #include <utils/KeyedVector.h>
 #include <utils/Log.h>
 #include <utils/threads.h>

 #include <stdlib.h>
 #include <stdio.h>
 #include <typeinfo>
 #include <sys/types.h>
 #include <sys/stat.h>
 #include <fcntl.h>
 #include <unistd.h>

 // compile with refcounting debugging enabled
 #define DEBUG_REFS                      0
 #define DEBUG_REFS_ENABLED_BY_DEFAULT   1
 #define DEBUG_REFS_CALLSTACK_ENABLED    1

 // log all reference counting operations
 #define PRINT_REFS                      0

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

 namespace android {

 #define INITIAL_STRONG_VALUE (1<<28)

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

 class RefBase::weakref_impl : public RefBase::weakref_type
 {
 public:
     volatile int32_t    mStrong;
     volatile int32_t    mWeak;
     RefBase* const      mBase;
     volatile int32_t    mFlags;


 #if !DEBUG_REFS

     weakref_impl(RefBase* base)
         : mStrong(INITIAL_STRONG_VALUE)
         , mWeak(0)
         , mBase(base)
         , mFlags(0)
     {
     }

     void addStrongRef(const void* /*id*/) { }
     void removeStrongRef(const void* /*id*/) { }
     void addWeakRef(const void* /*id*/) { }
     void removeWeakRef(const void* /*id*/) { }
     void printRefs() const { }
     void trackMe(bool, bool) { }

 #else

     weakref_impl(RefBase* base)
         : mStrong(INITIAL_STRONG_VALUE)
         , mWeak(0)
         , mBase(base)
         , mFlags(0)
         , mStrongRefs(NULL)
         , mWeakRefs(NULL)
         , mTrackEnabled(!!DEBUG_REFS_ENABLED_BY_DEFAULT)
         , mRetain(false)
     {
         //LOGI("NEW weakref_impl %p for RefBase %p", this, base);
     }

     ~weakref_impl()
     {
         LOG_ALWAYS_FATAL_IF(!mRetain && mStrongRefs != NULL, "Strong references remain!");
         LOG_ALWAYS_FATAL_IF(!mRetain && mWeakRefs != NULL, "Weak references remain!");
     }

     void addStrongRef(const void* id)
     {
         addRef(&mStrongRefs, id, mStrong);
     }

     void removeStrongRef(const void* id)
     {
         if (!mRetain)
             removeRef(&mStrongRefs, id);
         else
             addRef(&mStrongRefs, id, -mStrong);
     }

     void addWeakRef(const void* id)
     {
         addRef(&mWeakRefs, id, mWeak);
     }

     void removeWeakRef(const void* id)
     {
         if (!mRetain)
             removeRef(&mWeakRefs, id);
         else
             addRef(&mWeakRefs, id, -mWeak);
     }

     void trackMe(bool track, bool retain)
     {
         mTrackEnabled = track;
         mRetain = retain;
     }

     void printRefs() const
     {
         String8 text;

         {
             AutoMutex _l(const_cast<weakref_impl*>(this)->mMutex);

             char buf[128];
             sprintf(buf, "Strong references on RefBase %p (weakref_type %p):\n", mBase, this);
             text.append(buf);
             printRefsLocked(&text, mStrongRefs);
             sprintf(buf, "Weak references on RefBase %p (weakref_type %p):\n", mBase, this);
             text.append(buf);
             printRefsLocked(&text, mWeakRefs);
         }

         {
             char name[100];
             snprintf(name, 100, "/data/%p.stack", this);
             int rc = open(name, O_RDWR | O_CREAT | O_APPEND);
             if (rc >= 0) {
                 write(rc, text.string(), text.length());
                 close(rc);
                 LOGD("STACK TRACE for %p saved in %s", this, name);
             }
             else LOGE("FAILED TO PRINT STACK TRACE for %p in %s: %s", this,
                       name, strerror(errno));
         }
     }

 private:
     struct ref_entry
     {
         ref_entry* next;
         const void* id;
 #if DEBUG_REFS_CALLSTACK_ENABLED
         CallStack stack;
 #endif
         int32_t ref;
     };

     void addRef(ref_entry** refs, const void* id, int32_t mRef)
     {
         if (mTrackEnabled) {
             AutoMutex _l(mMutex);
             ref_entry* ref = new ref_entry;
             // Reference count at the time of the snapshot, but before the
             // update.  Positive value means we increment, negative--we
             // decrement the reference count.
             ref->ref = mRef;
             ref->id = id;
 #if DEBUG_REFS_CALLSTACK_ENABLED
             ref->stack.update(2);
 #endif

             ref->next = *refs;
             *refs = ref;
         }
     }

     void removeRef(ref_entry** refs, const void* id)
     {
         if (mTrackEnabled) {
             AutoMutex _l(mMutex);

             ref_entry* ref = *refs;
             while (ref != NULL) {
                 if (ref->id == id) {
                     *refs = ref->next;
                     delete ref;
                     return;
                 }

                 refs = &ref->next;
                 ref = *refs;
             }

             LOG_ALWAYS_FATAL("RefBase: removing id %p on RefBase %p (weakref_type %p) that doesn't exist!",
                              id, mBase, this);
         }
     }

     void printRefsLocked(String8* out, const ref_entry* refs) const
     {
         char buf[128];
         while (refs) {
             char inc = refs->ref >= 0 ? '+' : '-';
             sprintf(buf, "\t%c ID %p (ref %d):\n",
                     inc, refs->id, refs->ref);
             out->append(buf);
 #if DEBUG_REFS_CALLSTACK_ENABLED
             out->append(refs->stack.toString("\t\t"));
 #else
             out->append("\t\t(call stacks disabled)");
 #endif
             refs = refs->next;
         }
     }

     Mutex mMutex;
     ref_entry* mStrongRefs;
     ref_entry* mWeakRefs;

     bool mTrackEnabled;
     // Collect stack traces on addref and removeref, instead of deleting the stack references
     // on removeref that match the address ones.
     bool mRetain;

 #if 0
     void addRef(KeyedVector<const void*, int32_t>* refs, const void* id)
     {
         AutoMutex _l(mMutex);
         ssize_t i = refs->indexOfKey(id);
         if (i >= 0) {
             ++(refs->editValueAt(i));
         } else {
             i = refs->add(id, 1);
         }
     }

     void removeRef(KeyedVector<const void*, int32_t>* refs, const void* id)
     {
         AutoMutex _l(mMutex);
         ssize_t i = refs->indexOfKey(id);
         LOG_ALWAYS_FATAL_IF(i < 0, "RefBase: removing id %p that doesn't exist!", id);
         if (i >= 0) {
             int32_t val = --(refs->editValueAt(i));
             if (val == 0) {
                 refs->removeItemsAt(i);
             }
         }
     }

     void printRefs(const KeyedVector<const void*, int32_t>& refs)
     {
         const size_t N=refs.size();
         for (size_t i=0; i<N; i++) {
             printf("\tID %p: %d remain\n", refs.keyAt(i), refs.valueAt(i));
         }
     }

     mutable Mutex mMutex;
     KeyedVector<const void*, int32_t> mStrongRefs;
     KeyedVector<const void*, int32_t> mWeakRefs;
 #endif

 #endif
 };

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

 void RefBase::incStrong(const void* id) const
 {
     weakref_impl* const refs = mRefs;
     refs->addWeakRef(id);
     refs->incWeak(id);

     refs->addStrongRef(id);
     const int32_t c = android_atomic_inc(&refs->mStrong);
     LOG_ASSERT(c > 0, "incStrong() called on %p after last strong ref", refs);
 #if PRINT_REFS
     LOGD("incStrong of %p from %p: cnt=%d\n", this, id, c);
 #endif
     if (c != INITIAL_STRONG_VALUE)  {
         return;
     }

     android_atomic_add(-INITIAL_STRONG_VALUE, &refs->mStrong);
     const_cast<RefBase*>(this)->onFirstRef();
 }

 void RefBase::decStrong(const void* id) const
 {
     weakref_impl* const refs = mRefs;
     refs->removeStrongRef(id);
     const int32_t c = android_atomic_dec(&refs->mStrong);
 #if PRINT_REFS
     LOGD("decStrong of %p from %p: cnt=%d\n", this, id, c);
 #endif
     LOG_ASSERT(c >= 1, "decStrong() called on %p too many times", refs);
     if (c == 1) {
         const_cast<RefBase*>(this)->onLastStrongRef(id);
         if ((refs->mFlags&OBJECT_LIFETIME_WEAK) != OBJECT_LIFETIME_WEAK) {
             delete this;
         }
     }
     refs->removeWeakRef(id);
     refs->decWeak(id);
 }

 void RefBase::forceIncStrong(const void* id) const
 {
     weakref_impl* const refs = mRefs;
     refs->addWeakRef(id);
     refs->incWeak(id);

     refs->addStrongRef(id);
     const int32_t c = android_atomic_inc(&refs->mStrong);
     LOG_ASSERT(c >= 0, "forceIncStrong called on %p after ref count underflow",
                refs);
 #if PRINT_REFS
     LOGD("forceIncStrong of %p from %p: cnt=%d\n", this, id, c);
 #endif

     switch (c) {
     case INITIAL_STRONG_VALUE:
         android_atomic_add(-INITIAL_STRONG_VALUE, &refs->mStrong);
         // fall through...
     case 0:
         const_cast<RefBase*>(this)->onFirstRef();
     }
 }

 int32_t RefBase::getStrongCount() const
 {
     return mRefs->mStrong;
 }


 RefBase* RefBase::weakref_type::refBase() const
 {
     return static_cast<const weakref_impl*>(this)->mBase;
 }

 void RefBase::weakref_type::incWeak(const void* id)
 {
     weakref_impl* const impl = static_cast<weakref_impl*>(this);
     impl->addWeakRef(id);
     const int32_t c = android_atomic_inc(&impl->mWeak);
     LOG_ASSERT(c >= 0, "incWeak called on %p after last weak ref", this);
 }

 void RefBase::weakref_type::decWeak(const void* id)
 {
     weakref_impl* const impl = static_cast<weakref_impl*>(this);
     impl->removeWeakRef(id);
     const int32_t c = android_atomic_dec(&impl->mWeak);
     LOG_ASSERT(c >= 1, "decWeak called on %p too many times", this);
     if (c != 1) return;

     if ((impl->mFlags&OBJECT_LIFETIME_WEAK) != OBJECT_LIFETIME_WEAK) {
         if (impl->mStrong == INITIAL_STRONG_VALUE)
             delete impl->mBase;
         else {
 //            LOGV("Freeing refs %p of old RefBase %p\n", this, impl->mBase);
             delete impl;
         }
     } else {
         impl->mBase->onLastWeakRef(id);
         if ((impl->mFlags&OBJECT_LIFETIME_FOREVER) != OBJECT_LIFETIME_FOREVER) {
             delete impl->mBase;
         }
     }
 }

 bool RefBase::weakref_type::attemptIncStrong(const void* id)
 {
     incWeak(id);

     weakref_impl* const impl = static_cast<weakref_impl*>(this);

     int32_t curCount = impl->mStrong;
     LOG_ASSERT(curCount >= 0, "attemptIncStrong called on %p after underflow",
                this);
     while (curCount > 0 && curCount != INITIAL_STRONG_VALUE) {
         if (android_atomic_cmpxchg(curCount, curCount+1, &impl->mStrong) == 0) {
             break;
         }
         curCount = impl->mStrong;
     }

     if (curCount <= 0 || curCount == INITIAL_STRONG_VALUE) {
         bool allow;
         if (curCount == INITIAL_STRONG_VALUE) {
             // Attempting to acquire first strong reference...  this is allowed
             // if the object does NOT have a longer lifetime (meaning the
             // implementation doesn't need to see this), or if the implementation
             // allows it to happen.
             allow = (impl->mFlags&OBJECT_LIFETIME_WEAK) != OBJECT_LIFETIME_WEAK
                   || impl->mBase->onIncStrongAttempted(FIRST_INC_STRONG, id);
         } else {
             // Attempting to revive the object...  this is allowed
             // if the object DOES have a longer lifetime (so we can safely
             // call the object with only a weak ref) and the implementation
             // allows it to happen.
             allow = (impl->mFlags&OBJECT_LIFETIME_WEAK) == OBJECT_LIFETIME_WEAK
                   && impl->mBase->onIncStrongAttempted(FIRST_INC_STRONG, id);
         }
         if (!allow) {
             decWeak(id);
             return false;
         }
         curCount = android_atomic_inc(&impl->mStrong);

         // If the strong reference count has already been incremented by
         // someone else, the implementor of onIncStrongAttempted() is holding
         // an unneeded reference.  So call onLastStrongRef() here to remove it.
         // (No, this is not pretty.)  Note that we MUST NOT do this if we
         // are in fact acquiring the first reference.
         if (curCount > 0 && curCount < INITIAL_STRONG_VALUE) {
             impl->mBase->onLastStrongRef(id);
         }
     }

     impl->addWeakRef(id);
     impl->addStrongRef(id);

 #if PRINT_REFS
     LOGD("attemptIncStrong of %p from %p: cnt=%d\n", this, id, curCount);
 #endif

     if (curCount == INITIAL_STRONG_VALUE) {
         android_atomic_add(-INITIAL_STRONG_VALUE, &impl->mStrong);
         impl->mBase->onFirstRef();
     }

     return true;
 }

 bool RefBase::weakref_type::attemptIncWeak(const void* id)
 {
     weakref_impl* const impl = static_cast<weakref_impl*>(this);

     int32_t curCount = impl->mWeak;
     LOG_ASSERT(curCount >= 0, "attemptIncWeak called on %p after underflow",
                this);
     while (curCount > 0) {
         if (android_atomic_cmpxchg(curCount, curCount+1, &impl->mWeak) == 0) {
             break;
         }
         curCount = impl->mWeak;
     }

     if (curCount > 0) {
         impl->addWeakRef(id);
     }

     return curCount > 0;
 }

 int32_t RefBase::weakref_type::getWeakCount() const
 {
     return static_cast<const weakref_impl*>(this)->mWeak;
 }

 void RefBase::weakref_type::printRefs() const
 {
     static_cast<const weakref_impl*>(this)->printRefs();
 }

 void RefBase::weakref_type::trackMe(bool enable, bool retain)
 {
     static_cast<const weakref_impl*>(this)->trackMe(enable, retain);
 }

 RefBase::weakref_type* RefBase::createWeak(const void* id) const
 {
     mRefs->incWeak(id);
     return mRefs;
 }

 RefBase::weakref_type* RefBase::getWeakRefs() const
 {
     return mRefs;
 }

 RefBase::RefBase()
     : mRefs(new weakref_impl(this))
 {
 //    LOGV("Creating refs %p with RefBase %p\n", mRefs, this);
 }

 RefBase::~RefBase()
 {
 //    LOGV("Destroying RefBase %p (refs %p)\n", this, mRefs);
     if (mRefs->mWeak == 0) {
 //        LOGV("Freeing refs %p of old RefBase %p\n", mRefs, this);
         delete mRefs;
     }
 }

 void RefBase::extendObjectLifetime(int32_t mode)
 {
     android_atomic_or(mode, &mRefs->mFlags);
 }

 void RefBase::onFirstRef()
 {
 }

 void RefBase::onLastStrongRef(const void* /*id*/)
 {
 }

 bool RefBase::onIncStrongAttempted(uint32_t flags, const void* id)
 {
     return (flags&FIRST_INC_STRONG) ? true : false;
 }

 void RefBase::onLastWeakRef(const void* /*id*/)
 {
 }

 }; // namespace android
	/*
	* 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.
	*/

	#define LOG_TAG "RefBase"

	#include <utils/RefBase.h>

	#include <utils/Atomic.h>
	#include <utils/CallStack.h>
	#include <utils/KeyedVector.h>
	#include <utils/Log.h>
	#include <utils/threads.h>

	#include <stdlib.h>
	#include <stdio.h>
	#include <typeinfo>
	#include <sys/types.h>
	#include <sys/stat.h>
	#include <fcntl.h>
	#include <unistd.h>

	// compile with refcounting debugging enabled
	#define DEBUG_REFS 0
	#define DEBUG_REFS_ENABLED_BY_DEFAULT 1
	#define DEBUG_REFS_CALLSTACK_ENABLED 1

	// log all reference counting operations
	#define PRINT_REFS 0

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

	namespace android {

	#define INITIAL_STRONG_VALUE (1<<28)

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

	class RefBase::weakref_impl : public RefBase::weakref_type
	{
	public:
	volatile int32_t mStrong;
	volatile int32_t mWeak;
	RefBase* const mBase;
	volatile int32_t mFlags;


	#if !DEBUG_REFS

	weakref_impl(RefBase* base)
	: mStrong(INITIAL_STRONG_VALUE)
	, mWeak(0)
	, mBase(base)
	, mFlags(0)
	{
	}

	void addStrongRef(const void* /id/) { }
	void removeStrongRef(const void* /id/) { }
	void addWeakRef(const void* /id/) { }
	void removeWeakRef(const void* /id/) { }
	void printRefs() const { }
	void trackMe(bool, bool) { }

	#else

	weakref_impl(RefBase* base)
	: mStrong(INITIAL_STRONG_VALUE)
	, mWeak(0)
	, mBase(base)
	, mFlags(0)
	, mStrongRefs(NULL)
	, mWeakRefs(NULL)
	, mTrackEnabled(!!DEBUG_REFS_ENABLED_BY_DEFAULT)
	, mRetain(false)
	{
	//LOGI("NEW weakref_impl %p for RefBase %p", this, base);
	}

	~weakref_impl()
	{
	LOG_ALWAYS_FATAL_IF(!mRetain && mStrongRefs != NULL, "Strong references remain!");
	LOG_ALWAYS_FATAL_IF(!mRetain && mWeakRefs != NULL, "Weak references remain!");
	}

	void addStrongRef(const void* id)
	{
	addRef(&mStrongRefs, id, mStrong);
	}

	void removeStrongRef(const void* id)
	{
	if (!mRetain)
	removeRef(&mStrongRefs, id);
	else
	addRef(&mStrongRefs, id, -mStrong);
	}

	void addWeakRef(const void* id)
	{
	addRef(&mWeakRefs, id, mWeak);
	}

	void removeWeakRef(const void* id)
	{
	if (!mRetain)
	removeRef(&mWeakRefs, id);
	else
	addRef(&mWeakRefs, id, -mWeak);
	}

	void trackMe(bool track, bool retain)
	{
	mTrackEnabled = track;
	mRetain = retain;
	}

	void printRefs() const
	{
	String8 text;

	{
	AutoMutex _l(const_cast<weakref_impl*>(this)->mMutex);

	char buf[128];
	sprintf(buf, "Strong references on RefBase %p (weakref_type %p):\n", mBase, this);
	text.append(buf);
	printRefsLocked(&text, mStrongRefs);
	sprintf(buf, "Weak references on RefBase %p (weakref_type %p):\n", mBase, this);
	text.append(buf);
	printRefsLocked(&text, mWeakRefs);
	}

	{
	char name[100];
	snprintf(name, 100, "/data/%p.stack", this);
	int rc = open(name, O_RDWR \| O_CREAT \| O_APPEND);
	if (rc >= 0) {
	write(rc, text.string(), text.length());
	close(rc);
	LOGD("STACK TRACE for %p saved in %s", this, name);
	}
	else LOGE("FAILED TO PRINT STACK TRACE for %p in %s: %s", this,
	name, strerror(errno));
	}
	}

	private:
	struct ref_entry
	{
	ref_entry* next;
	const void* id;
	#if DEBUG_REFS_CALLSTACK_ENABLED
	CallStack stack;
	#endif
	int32_t ref;
	};

	void addRef(ref_entry** refs, const void* id, int32_t mRef)
	{
	if (mTrackEnabled) {
	AutoMutex _l(mMutex);
	ref_entry* ref = new ref_entry;
	// Reference count at the time of the snapshot, but before the
	// update. Positive value means we increment, negative--we
	// decrement the reference count.
	ref->ref = mRef;
	ref->id = id;
	#if DEBUG_REFS_CALLSTACK_ENABLED
	ref->stack.update(2);
	#endif

	ref->next = *refs;
	*refs = ref;
	}
	}

	void removeRef(ref_entry** refs, const void* id)
	{
	if (mTrackEnabled) {
	AutoMutex _l(mMutex);

	ref_entry* ref = *refs;
	while (ref != NULL) {
	if (ref->id == id) {
	*refs = ref->next;
	delete ref;
	return;
	}

	refs = &ref->next;
	ref = *refs;
	}

	LOG_ALWAYS_FATAL("RefBase: removing id %p on RefBase %p (weakref_type %p) that doesn't exist!",
	id, mBase, this);
	}
	}

	void printRefsLocked(String8* out, const ref_entry* refs) const
	{
	char buf[128];
	while (refs) {
	char inc = refs->ref >= 0 ? '+' : '-';
	sprintf(buf, "\t%c ID %p (ref %d):\n",
	inc, refs->id, refs->ref);
	out->append(buf);
	#if DEBUG_REFS_CALLSTACK_ENABLED
	out->append(refs->stack.toString("\t\t"));
	#else
	out->append("\t\t(call stacks disabled)");
	#endif
	refs = refs->next;
	}
	}

	Mutex mMutex;
	ref_entry* mStrongRefs;
	ref_entry* mWeakRefs;

	bool mTrackEnabled;
	// Collect stack traces on addref and removeref, instead of deleting the stack references
	// on removeref that match the address ones.
	bool mRetain;

	#if 0
	void addRef(KeyedVector<const void, int32_t> refs, const void* id)
	{
	AutoMutex _l(mMutex);
	ssize_t i = refs->indexOfKey(id);
	if (i >= 0) {
	++(refs->editValueAt(i));
	} else {
	i = refs->add(id, 1);
	}
	}

	void removeRef(KeyedVector<const void, int32_t> refs, const void* id)
	{
	AutoMutex _l(mMutex);
	ssize_t i = refs->indexOfKey(id);
	LOG_ALWAYS_FATAL_IF(i < 0, "RefBase: removing id %p that doesn't exist!", id);
	if (i >= 0) {
	int32_t val = --(refs->editValueAt(i));
	if (val == 0) {
	refs->removeItemsAt(i);
	}
	}
	}

	void printRefs(const KeyedVector<const void*, int32_t>& refs)
	{
	const size_t N=refs.size();
	for (size_t i=0; i<N; i++) {
	printf("\tID %p: %d remain\n", refs.keyAt(i), refs.valueAt(i));
	}
	}

	mutable Mutex mMutex;
	KeyedVector<const void*, int32_t> mStrongRefs;
	KeyedVector<const void*, int32_t> mWeakRefs;
	#endif

	#endif
	};

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

	void RefBase::incStrong(const void* id) const
	{
	weakref_impl* const refs = mRefs;
	refs->addWeakRef(id);
	refs->incWeak(id);

	refs->addStrongRef(id);
	const int32_t c = android_atomic_inc(&refs->mStrong);
	LOG_ASSERT(c > 0, "incStrong() called on %p after last strong ref", refs);
	#if PRINT_REFS
	LOGD("incStrong of %p from %p: cnt=%d\n", this, id, c);
	#endif
	if (c != INITIAL_STRONG_VALUE) {
	return;
	}

	android_atomic_add(-INITIAL_STRONG_VALUE, &refs->mStrong);
	const_cast<RefBase*>(this)->onFirstRef();
	}

	void RefBase::decStrong(const void* id) const
	{
	weakref_impl* const refs = mRefs;
	refs->removeStrongRef(id);
	const int32_t c = android_atomic_dec(&refs->mStrong);
	#if PRINT_REFS
	LOGD("decStrong of %p from %p: cnt=%d\n", this, id, c);
	#endif
	LOG_ASSERT(c >= 1, "decStrong() called on %p too many times", refs);
	if (c == 1) {
	const_cast<RefBase*>(this)->onLastStrongRef(id);
	if ((refs->mFlags&OBJECT_LIFETIME_WEAK) != OBJECT_LIFETIME_WEAK) {
	delete this;
	}
	}
	refs->removeWeakRef(id);
	refs->decWeak(id);
	}

	void RefBase::forceIncStrong(const void* id) const
	{
	weakref_impl* const refs = mRefs;
	refs->addWeakRef(id);
	refs->incWeak(id);

	refs->addStrongRef(id);
	const int32_t c = android_atomic_inc(&refs->mStrong);
	LOG_ASSERT(c >= 0, "forceIncStrong called on %p after ref count underflow",
	refs);
	#if PRINT_REFS
	LOGD("forceIncStrong of %p from %p: cnt=%d\n", this, id, c);
	#endif

	switch (c) {
	case INITIAL_STRONG_VALUE:
	android_atomic_add(-INITIAL_STRONG_VALUE, &refs->mStrong);
	// fall through...
	case 0:
	const_cast<RefBase*>(this)->onFirstRef();
	}
	}

	int32_t RefBase::getStrongCount() const
	{
	return mRefs->mStrong;
	}



	RefBase* RefBase::weakref_type::refBase() const
	{
	return static_cast<const weakref_impl*>(this)->mBase;
	}

	void RefBase::weakref_type::incWeak(const void* id)
	{
	weakref_impl* const impl = static_cast<weakref_impl*>(this);
	impl->addWeakRef(id);
	const int32_t c = android_atomic_inc(&impl->mWeak);
	LOG_ASSERT(c >= 0, "incWeak called on %p after last weak ref", this);
	}

	void RefBase::weakref_type::decWeak(const void* id)
	{
	weakref_impl* const impl = static_cast<weakref_impl*>(this);
	impl->removeWeakRef(id);
	const int32_t c = android_atomic_dec(&impl->mWeak);
	LOG_ASSERT(c >= 1, "decWeak called on %p too many times", this);
	if (c != 1) return;

	if ((impl->mFlags&OBJECT_LIFETIME_WEAK) != OBJECT_LIFETIME_WEAK) {
	if (impl->mStrong == INITIAL_STRONG_VALUE)
	delete impl->mBase;
	else {
	// LOGV("Freeing refs %p of old RefBase %p\n", this, impl->mBase);
	delete impl;
	}
	} else {
	impl->mBase->onLastWeakRef(id);
	if ((impl->mFlags&OBJECT_LIFETIME_FOREVER) != OBJECT_LIFETIME_FOREVER) {
	delete impl->mBase;
	}
	}
	}

	bool RefBase::weakref_type::attemptIncStrong(const void* id)
	{
	incWeak(id);

	weakref_impl* const impl = static_cast<weakref_impl*>(this);

	int32_t curCount = impl->mStrong;
	LOG_ASSERT(curCount >= 0, "attemptIncStrong called on %p after underflow",
	this);
	while (curCount > 0 && curCount != INITIAL_STRONG_VALUE) {
	if (android_atomic_cmpxchg(curCount, curCount+1, &impl->mStrong) == 0) {
	break;
	}
	curCount = impl->mStrong;
	}

	if (curCount <= 0 \|\| curCount == INITIAL_STRONG_VALUE) {
	bool allow;
	if (curCount == INITIAL_STRONG_VALUE) {
	// Attempting to acquire first strong reference... this is allowed
	// if the object does NOT have a longer lifetime (meaning the
	// implementation doesn't need to see this), or if the implementation
	// allows it to happen.
	allow = (impl->mFlags&OBJECT_LIFETIME_WEAK) != OBJECT_LIFETIME_WEAK
	\|\| impl->mBase->onIncStrongAttempted(FIRST_INC_STRONG, id);
	} else {
	// Attempting to revive the object... this is allowed
	// if the object DOES have a longer lifetime (so we can safely
	// call the object with only a weak ref) and the implementation
	// allows it to happen.
	allow = (impl->mFlags&OBJECT_LIFETIME_WEAK) == OBJECT_LIFETIME_WEAK
	&& impl->mBase->onIncStrongAttempted(FIRST_INC_STRONG, id);
	}
	if (!allow) {
	decWeak(id);
	return false;
	}
	curCount = android_atomic_inc(&impl->mStrong);

	// If the strong reference count has already been incremented by
	// someone else, the implementor of onIncStrongAttempted() is holding
	// an unneeded reference. So call onLastStrongRef() here to remove it.
	// (No, this is not pretty.) Note that we MUST NOT do this if we
	// are in fact acquiring the first reference.
	if (curCount > 0 && curCount < INITIAL_STRONG_VALUE) {
	impl->mBase->onLastStrongRef(id);
	}
	}

	impl->addWeakRef(id);
	impl->addStrongRef(id);

	#if PRINT_REFS
	LOGD("attemptIncStrong of %p from %p: cnt=%d\n", this, id, curCount);
	#endif

	if (curCount == INITIAL_STRONG_VALUE) {
	android_atomic_add(-INITIAL_STRONG_VALUE, &impl->mStrong);
	impl->mBase->onFirstRef();
	}

	return true;
	}

	bool RefBase::weakref_type::attemptIncWeak(const void* id)
	{
	weakref_impl* const impl = static_cast<weakref_impl*>(this);

	int32_t curCount = impl->mWeak;
	LOG_ASSERT(curCount >= 0, "attemptIncWeak called on %p after underflow",
	this);
	while (curCount > 0) {
	if (android_atomic_cmpxchg(curCount, curCount+1, &impl->mWeak) == 0) {
	break;
	}
	curCount = impl->mWeak;
	}

	if (curCount > 0) {
	impl->addWeakRef(id);
	}

	return curCount > 0;
	}

	int32_t RefBase::weakref_type::getWeakCount() const
	{
	return static_cast<const weakref_impl*>(this)->mWeak;
	}

	void RefBase::weakref_type::printRefs() const
	{
	static_cast<const weakref_impl*>(this)->printRefs();
	}

	void RefBase::weakref_type::trackMe(bool enable, bool retain)
	{
	static_cast<const weakref_impl*>(this)->trackMe(enable, retain);
	}

	RefBase::weakref_type* RefBase::createWeak(const void* id) const
	{
	mRefs->incWeak(id);
	return mRefs;
	}

	RefBase::weakref_type* RefBase::getWeakRefs() const
	{
	return mRefs;
	}

	RefBase::RefBase()
	: mRefs(new weakref_impl(this))
	{
	// LOGV("Creating refs %p with RefBase %p\n", mRefs, this);
	}

	RefBase::~RefBase()
	{
	// LOGV("Destroying RefBase %p (refs %p)\n", this, mRefs);
	if (mRefs->mWeak == 0) {
	// LOGV("Freeing refs %p of old RefBase %p\n", mRefs, this);
	delete mRefs;
	}
	}

	void RefBase::extendObjectLifetime(int32_t mode)
	{
	android_atomic_or(mode, &mRefs->mFlags);
	}

	void RefBase::onFirstRef()
	{
	}

	void RefBase::onLastStrongRef(const void* /id/)
	{
	}

	bool RefBase::onIncStrongAttempted(uint32_t flags, const void* id)
	{
	return (flags&FIRST_INC_STRONG) ? true : false;
	}

	void RefBase::onLastWeakRef(const void* /id/)
	{
	}

	}; // namespace android