forked from mirrors/gecko-dev
9717c27492
Because DelayedRunnables are fire-and-forget, there is no way for a targeted EventTarget to clean them up on shutdown. Thus if a timer fires after EventTarget shutdown it will fail to dispatch the timer event, and avoid releasing the timer callback because it's not on the targeted thread. This causes a leak as there is a ref-cycle between nsTimerImpl::mCallback and DelayedRunnable::mTimer. This patch adds nsIDelayedRunnableObserver for a target to observe which DelayedRunnables are relying on their timer to run them. This allows the target to schedule a shutdown task to cancel those timers and release the runnables on the target thread. Supported DelayedRunnable targets with this patch are TaskQueues, eventqueue-based nsThreads and XPCOMThreadWrappers that wrap a supported nsThread. An assertion makes sure at runtime that future new uses of DelayedRunnable target nsIDelayedRunnableObserver-supported event targets. Differential Revision: https://phabricator.services.mozilla.com/D109781
50 lines
1.4 KiB
C++
50 lines
1.4 KiB
C++
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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/* vim: set ts=8 sts=2 et sw=2 tw=80: */
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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 XPCOM_THREADS_DELAYEDRUNNABLE_H_
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#define XPCOM_THREADS_DELAYEDRUNNABLE_H_
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#include "mozilla/TimeStamp.h"
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#include "nsCOMPtr.h"
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#include "nsIDelayedRunnableObserver.h"
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#include "nsIRunnable.h"
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#include "nsITimer.h"
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#include "nsThreadUtils.h"
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namespace mozilla {
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class DelayedRunnable : public Runnable, public nsITimerCallback {
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public:
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DelayedRunnable(already_AddRefed<nsIEventTarget> aTarget,
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already_AddRefed<nsIRunnable> aRunnable, uint32_t aDelay);
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NS_DECL_ISUPPORTS_INHERITED
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NS_DECL_NSIRUNNABLE
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NS_DECL_NSITIMERCALLBACK
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nsresult Init();
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/**
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* Cancels the underlying timer. Called when the target is going away, so the
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* runnable can be released safely on the target thread.
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*/
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void CancelTimer();
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private:
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~DelayedRunnable() = default;
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nsresult DoRun();
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const nsCOMPtr<nsIEventTarget> mTarget;
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const nsCOMPtr<nsIDelayedRunnableObserver> mObserver;
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nsCOMPtr<nsIRunnable> mWrappedRunnable;
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nsCOMPtr<nsITimer> mTimer;
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const TimeStamp mDelayedFrom;
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uint32_t mDelay;
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};
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} // namespace mozilla
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#endif
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