зеркало из https://github.com/mozilla/gecko-dev.git
124 строки
2.7 KiB
C++
124 строки
2.7 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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#include "nsEventQueue.h"
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#include "nsAutoPtr.h"
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#include "prlog.h"
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#include "nsThreadUtils.h"
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#include "prthread.h"
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#include "mozilla/ChaosMode.h"
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using namespace mozilla;
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#ifdef PR_LOGGING
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static PRLogModuleInfo*
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GetLog()
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{
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static PRLogModuleInfo* sLog;
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if (!sLog) {
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sLog = PR_NewLogModule("nsEventQueue");
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}
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return sLog;
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}
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#endif
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#ifdef LOG
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#undef LOG
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#endif
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#define LOG(args) PR_LOG(GetLog(), PR_LOG_DEBUG, args)
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nsEventQueue::nsEventQueue()
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: mReentrantMonitor("nsEventQueue.mReentrantMonitor")
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, mHead(nullptr)
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, mTail(nullptr)
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, mOffsetHead(0)
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, mOffsetTail(0)
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{
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}
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nsEventQueue::~nsEventQueue()
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{
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// It'd be nice to be able to assert that no one else is holding the monitor,
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// but NSPR doesn't really expose APIs for it.
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NS_ASSERTION(IsEmpty(),
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"Non-empty event queue being destroyed; events being leaked.");
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if (mHead) {
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FreePage(mHead);
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}
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}
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bool
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nsEventQueue::GetEvent(bool aMayWait, nsIRunnable** aResult)
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{
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{
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ReentrantMonitorAutoEnter mon(mReentrantMonitor);
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while (IsEmpty()) {
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if (!aMayWait) {
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if (aResult) {
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*aResult = nullptr;
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}
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return false;
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}
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LOG(("EVENTQ(%p): wait begin\n", this));
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mon.Wait();
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LOG(("EVENTQ(%p): wait end\n", this));
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}
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if (aResult) {
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*aResult = mHead->mEvents[mOffsetHead++];
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// Check if mHead points to empty Page
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if (mOffsetHead == EVENTS_PER_PAGE) {
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Page* dead = mHead;
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mHead = mHead->mNext;
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FreePage(dead);
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mOffsetHead = 0;
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}
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}
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}
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return true;
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}
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void
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nsEventQueue::PutEvent(nsIRunnable* aRunnable)
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{
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// Avoid calling AddRef+Release while holding our monitor.
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nsRefPtr<nsIRunnable> event(aRunnable);
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if (ChaosMode::isActive(ChaosMode::ThreadScheduling)) {
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// With probability 0.5, yield so other threads have a chance to
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// dispatch events to this queue first.
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if (ChaosMode::randomUint32LessThan(2)) {
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PR_Sleep(PR_INTERVAL_NO_WAIT);
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}
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}
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ReentrantMonitorAutoEnter mon(mReentrantMonitor);
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if (!mHead) {
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mHead = NewPage();
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MOZ_ASSERT(mHead);
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mTail = mHead;
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mOffsetHead = 0;
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mOffsetTail = 0;
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} else if (mOffsetTail == EVENTS_PER_PAGE) {
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Page* page = NewPage();
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MOZ_ASSERT(page);
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mTail->mNext = page;
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mTail = page;
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mOffsetTail = 0;
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}
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event.swap(mTail->mEvents[mOffsetTail]);
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++mOffsetTail;
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LOG(("EVENTQ(%p): notify\n", this));
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mon.NotifyAll();
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}
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