72 lines
2 KiB
C++
72 lines
2 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 MOZILLA_GFX_SYNCHRONOUSTASK_H
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#define MOZILLA_GFX_SYNCHRONOUSTASK_H
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#include "mozilla/ReentrantMonitor.h" // for ReentrantMonitor, etc
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namespace mozilla {
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namespace layers {
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// Helper that creates a monitor and a "done" flag, then enters the monitor.
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class MOZ_STACK_CLASS SynchronousTask {
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friend class AutoCompleteTask;
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public:
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explicit SynchronousTask(const char* name) : mMonitor(name), mDone(false) {}
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nsresult Wait(PRIntervalTime aInterval = PR_INTERVAL_NO_TIMEOUT) {
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ReentrantMonitorAutoEnter lock(mMonitor);
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// For indefinite timeouts, wait in a while loop to handle spurious
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// wakeups.
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while (aInterval == PR_INTERVAL_NO_TIMEOUT && !mDone) {
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mMonitor.Wait();
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}
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// For finite timeouts, we only check once for completion, and otherwise
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// rely on the ReentrantMonitor to manage the interval. If the monitor
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// returns too early, we'll never know, but we can check if the mDone
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// flag was set to true, indicating that the task finished successfully.
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if (!mDone) {
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// We ignore the return value from ReentrantMonitor::Wait, because it's
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// always NS_OK, even in the case of timeout.
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mMonitor.Wait(aInterval);
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if (!mDone) {
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return NS_ERROR_ABORT;
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}
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}
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return NS_OK;
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}
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private:
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void Complete() {
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ReentrantMonitorAutoEnter lock(mMonitor);
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mDone = true;
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mMonitor.NotifyAll();
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}
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private:
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ReentrantMonitor mMonitor MOZ_UNANNOTATED;
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bool mDone;
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};
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class MOZ_STACK_CLASS AutoCompleteTask final {
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public:
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explicit AutoCompleteTask(SynchronousTask* aTask) : mTask(aTask) {}
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~AutoCompleteTask() { mTask->Complete(); }
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private:
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SynchronousTask* mTask;
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};
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} // namespace layers
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} // namespace mozilla
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#endif
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