michael@0: /* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 2 -*-
michael@0:  * This Source Code Form is subject to the terms of the Mozilla Public
michael@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0:  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: 
michael@0: #ifndef MOZILLA_ATOMICREFCOUNTEDWITHFINALIZE_H_
michael@0: #define MOZILLA_ATOMICREFCOUNTEDWITHFINALIZE_H_
michael@0: 
michael@0: #include "mozilla/RefPtr.h"
michael@0: #include "mozilla/NullPtr.h"
michael@0: 
michael@0: namespace mozilla {
michael@0: 
michael@0: template<typename T>
michael@0: class AtomicRefCountedWithFinalize
michael@0: {
michael@0:   protected:
michael@0:     AtomicRefCountedWithFinalize()
michael@0:       : mRecycleCallback(nullptr)
michael@0:       , mRefCount(0)
michael@0:     {}
michael@0: 
michael@0:     ~AtomicRefCountedWithFinalize() {}
michael@0: 
michael@0:   public:
michael@0:     void AddRef() {
michael@0:       MOZ_ASSERT(mRefCount >= 0);
michael@0:       ++mRefCount;
michael@0:     }
michael@0: 
michael@0:     void Release() {
michael@0:       MOZ_ASSERT(mRefCount > 0);
michael@0:       // Read mRecycleCallback early so that it does not get set to
michael@0:       // deleted memory, if the object is goes away.
michael@0:       RecycleCallback recycleCallback = mRecycleCallback;
michael@0:       int currCount = --mRefCount;
michael@0:       if (0 == currCount) {
michael@0:         // Recycle listeners must call ClearRecycleCallback
michael@0:         // before releasing their strong reference.
michael@0:         MOZ_ASSERT(mRecycleCallback == nullptr);
michael@0: #ifdef DEBUG
michael@0:         mRefCount = detail::DEAD;
michael@0: #endif
michael@0:         T* derived = static_cast<T*>(this);
michael@0:         derived->Finalize();
michael@0:         delete derived;
michael@0:       } else if (1 == currCount && recycleCallback) {
michael@0:         T* derived = static_cast<T*>(this);
michael@0:         recycleCallback(derived, mClosure);
michael@0:       }
michael@0:     }
michael@0: 
michael@0:     typedef void (*RecycleCallback)(T* aObject, void* aClosure);
michael@0:     /**
michael@0:      * Set a callback responsible for recycling this object
michael@0:      * before it is finalized.
michael@0:      */
michael@0:     void SetRecycleCallback(RecycleCallback aCallback, void* aClosure)
michael@0:     {
michael@0:       mRecycleCallback = aCallback;
michael@0:       mClosure = aClosure;
michael@0:     }
michael@0:     void ClearRecycleCallback() { SetRecycleCallback(nullptr, nullptr); }
michael@0: 
michael@0: private:
michael@0:     RecycleCallback mRecycleCallback;
michael@0:     void *mClosure;
michael@0:     Atomic<int> mRefCount;
michael@0: };
michael@0: 
michael@0: }
michael@0: 
michael@0: #endif