зеркало из https://github.com/mozilla/gecko-dev.git
105 строки
2.9 KiB
C++
105 строки
2.9 KiB
C++
/* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 2 -*-
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* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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#ifndef MOZILLA_ATOMICREFCOUNTEDWITHFINALIZE_H_
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#define MOZILLA_ATOMICREFCOUNTEDWITHFINALIZE_H_
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#include "mozilla/RefPtr.h"
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#include "mozilla/NullPtr.h"
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#include "mozilla/Likely.h"
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#include "MainThreadUtils.h"
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#include "base/message_loop.h"
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#include "base/task.h"
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namespace mozilla {
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template<typename T>
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class AtomicRefCountedWithFinalize
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{
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protected:
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AtomicRefCountedWithFinalize()
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: mRecycleCallback(nullptr)
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, mRefCount(0)
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, mMessageLoopToPostDestructionTo(nullptr)
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{}
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~AtomicRefCountedWithFinalize() {}
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void SetMessageLoopToPostDestructionTo(MessageLoop* l) {
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MOZ_ASSERT(NS_IsMainThread());
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mMessageLoopToPostDestructionTo = l;
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}
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static void DestroyToBeCalledOnMainThread(T* ptr) {
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MOZ_ASSERT(NS_IsMainThread());
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delete ptr;
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}
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public:
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void AddRef() {
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MOZ_ASSERT(mRefCount >= 0);
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++mRefCount;
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}
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void Release() {
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MOZ_ASSERT(mRefCount > 0);
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// Read mRecycleCallback early so that it does not get set to
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// deleted memory, if the object is goes away.
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RecycleCallback recycleCallback = mRecycleCallback;
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int currCount = --mRefCount;
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if (0 == currCount) {
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// Recycle listeners must call ClearRecycleCallback
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// before releasing their strong reference.
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MOZ_ASSERT(mRecycleCallback == nullptr);
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#ifdef DEBUG
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mRefCount = detail::DEAD;
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#endif
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T* derived = static_cast<T*>(this);
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derived->Finalize();
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if (MOZ_LIKELY(!mMessageLoopToPostDestructionTo)) {
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delete derived;
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} else {
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if (MOZ_LIKELY(NS_IsMainThread())) {
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delete derived;
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} else {
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mMessageLoopToPostDestructionTo->PostTask(
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FROM_HERE,
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NewRunnableFunction(&DestroyToBeCalledOnMainThread, derived));
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}
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}
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} else if (1 == currCount && recycleCallback) {
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T* derived = static_cast<T*>(this);
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recycleCallback(derived, mClosure);
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}
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}
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typedef void (*RecycleCallback)(T* aObject, void* aClosure);
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/**
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* Set a callback responsible for recycling this object
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* before it is finalized.
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*/
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void SetRecycleCallback(RecycleCallback aCallback, void* aClosure)
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{
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mRecycleCallback = aCallback;
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mClosure = aClosure;
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}
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void ClearRecycleCallback() { SetRecycleCallback(nullptr, nullptr); }
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bool HasRecycleCallback() const
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{
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return !!mRecycleCallback;
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}
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private:
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RecycleCallback mRecycleCallback;
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void *mClosure;
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Atomic<int> mRefCount;
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MessageLoop *mMessageLoopToPostDestructionTo;
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};
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}
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#endif
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