mirror of
https://github.com/mozilla/gecko-dev.git
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350 lines
9.1 KiB
C++
350 lines
9.1 KiB
C++
/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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/* vim:set ts=2 sw=2 sts=2 et cindent: */
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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 "nsIClassInfoImpl.h"
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#include "nsThreadPool.h"
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#include "nsThreadManager.h"
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#include "nsThread.h"
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#include "nsMemory.h"
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#include "nsAutoPtr.h"
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#include "prinrval.h"
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#include "prlog.h"
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using namespace mozilla;
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#ifdef PR_LOGGING
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static PRLogModuleInfo *sLog = PR_NewLogModule("nsThreadPool");
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#endif
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#define LOG(args) PR_LOG(sLog, PR_LOG_DEBUG, args)
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// DESIGN:
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// o Allocate anonymous threads.
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// o Use nsThreadPool::Run as the main routine for each thread.
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// o Each thread waits on the event queue's monitor, checking for
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// pending events and rescheduling itself as an idle thread.
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#define DEFAULT_THREAD_LIMIT 4
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#define DEFAULT_IDLE_THREAD_LIMIT 1
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#define DEFAULT_IDLE_THREAD_TIMEOUT PR_SecondsToInterval(60)
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NS_IMPL_THREADSAFE_ADDREF(nsThreadPool)
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NS_IMPL_THREADSAFE_RELEASE(nsThreadPool)
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NS_IMPL_CLASSINFO(nsThreadPool, NULL, nsIClassInfo::THREADSAFE,
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NS_THREADPOOL_CID)
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NS_IMPL_QUERY_INTERFACE3_CI(nsThreadPool, nsIThreadPool, nsIEventTarget,
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nsIRunnable)
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NS_IMPL_CI_INTERFACE_GETTER2(nsThreadPool, nsIThreadPool, nsIEventTarget)
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nsThreadPool::nsThreadPool()
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: mThreadLimit(DEFAULT_THREAD_LIMIT)
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, mIdleThreadLimit(DEFAULT_IDLE_THREAD_LIMIT)
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, mIdleThreadTimeout(DEFAULT_IDLE_THREAD_TIMEOUT)
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, mIdleCount(0)
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, mShutdown(false)
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{
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}
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nsThreadPool::~nsThreadPool()
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{
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Shutdown();
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}
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nsresult
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nsThreadPool::PutEvent(nsIRunnable *event)
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{
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// Avoid spawning a new thread while holding the event queue lock...
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bool spawnThread = false;
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{
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ReentrantMonitorAutoEnter mon(mEvents.GetReentrantMonitor());
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LOG(("THRD-P(%p) put [%d %d %d]\n", this, mIdleCount, mThreads.Count(),
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mThreadLimit));
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NS_ASSERTION(mIdleCount <= (PRUint32) mThreads.Count(), "oops");
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// Make sure we have a thread to service this event.
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if (mIdleCount == 0 && mThreads.Count() < (PRInt32) mThreadLimit)
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spawnThread = true;
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mEvents.PutEvent(event);
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}
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LOG(("THRD-P(%p) put [spawn=%d]\n", this, spawnThread));
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if (!spawnThread)
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return NS_OK;
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nsCOMPtr<nsIThread> thread;
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nsThreadManager::get()->NewThread(0,
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nsIThreadManager::DEFAULT_STACK_SIZE,
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getter_AddRefs(thread));
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NS_ENSURE_STATE(thread);
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bool killThread = false;
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{
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ReentrantMonitorAutoEnter mon(mEvents.GetReentrantMonitor());
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if (mThreads.Count() < (PRInt32) mThreadLimit) {
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mThreads.AppendObject(thread);
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} else {
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killThread = true; // okay, we don't need this thread anymore
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}
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}
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LOG(("THRD-P(%p) put [%p kill=%d]\n", this, thread.get(), killThread));
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if (killThread) {
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thread->Shutdown();
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} else {
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thread->Dispatch(this, NS_DISPATCH_NORMAL);
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}
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return NS_OK;
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}
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void
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nsThreadPool::ShutdownThread(nsIThread *thread)
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{
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LOG(("THRD-P(%p) shutdown async [%p]\n", this, thread));
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// This method is responsible for calling Shutdown on |thread|. This must be
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// done from some other thread, so we use the main thread of the application.
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NS_ASSERTION(!NS_IsMainThread(), "wrong thread");
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nsRefPtr<nsIRunnable> r = NS_NewRunnableMethod(thread, &nsIThread::Shutdown);
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NS_DispatchToMainThread(r);
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}
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NS_IMETHODIMP
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nsThreadPool::Run()
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{
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LOG(("THRD-P(%p) enter\n", this));
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mThreadNaming.SetThreadPoolName(mName);
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nsCOMPtr<nsIThread> current;
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nsThreadManager::get()->GetCurrentThread(getter_AddRefs(current));
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bool shutdownThreadOnExit = false;
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bool exitThread = false;
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bool wasIdle = false;
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PRIntervalTime idleSince;
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nsCOMPtr<nsIThreadPoolListener> listener;
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{
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ReentrantMonitorAutoEnter mon(mEvents.GetReentrantMonitor());
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listener = mListener;
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}
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if (listener) {
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listener->OnThreadCreated();
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}
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do {
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nsCOMPtr<nsIRunnable> event;
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{
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ReentrantMonitorAutoEnter mon(mEvents.GetReentrantMonitor());
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if (!mEvents.GetPendingEvent(getter_AddRefs(event))) {
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PRIntervalTime now = PR_IntervalNow();
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PRIntervalTime timeout = PR_MillisecondsToInterval(mIdleThreadTimeout);
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// If we are shutting down, then don't keep any idle threads
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if (mShutdown) {
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exitThread = true;
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} else {
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if (wasIdle) {
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// if too many idle threads or idle for too long, then bail.
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if (mIdleCount > mIdleThreadLimit || (now - idleSince) >= timeout)
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exitThread = true;
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} else {
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// if would be too many idle threads...
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if (mIdleCount == mIdleThreadLimit) {
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exitThread = true;
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} else {
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++mIdleCount;
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idleSince = now;
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wasIdle = true;
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}
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}
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}
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if (exitThread) {
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if (wasIdle)
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--mIdleCount;
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shutdownThreadOnExit = mThreads.RemoveObject(current);
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} else {
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PRIntervalTime delta = timeout - (now - idleSince);
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LOG(("THRD-P(%p) waiting [%d]\n", this, delta));
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mon.Wait(delta);
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}
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} else if (wasIdle) {
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wasIdle = false;
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--mIdleCount;
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}
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}
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if (event) {
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LOG(("THRD-P(%p) running [%p]\n", this, event.get()));
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event->Run();
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}
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} while (!exitThread);
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if (listener) {
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listener->OnThreadShuttingDown();
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}
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if (shutdownThreadOnExit) {
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ShutdownThread(current);
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}
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LOG(("THRD-P(%p) leave\n", this));
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return NS_OK;
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}
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NS_IMETHODIMP
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nsThreadPool::Dispatch(nsIRunnable *event, PRUint32 flags)
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{
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LOG(("THRD-P(%p) dispatch [%p %x]\n", this, event, flags));
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NS_ENSURE_STATE(!mShutdown);
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if (flags & DISPATCH_SYNC) {
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nsCOMPtr<nsIThread> thread;
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nsThreadManager::get()->GetCurrentThread(getter_AddRefs(thread));
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NS_ENSURE_STATE(thread);
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nsRefPtr<nsThreadSyncDispatch> wrapper =
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new nsThreadSyncDispatch(thread, event);
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PutEvent(wrapper);
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while (wrapper->IsPending())
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NS_ProcessNextEvent(thread);
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} else {
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NS_ASSERTION(flags == NS_DISPATCH_NORMAL, "unexpected dispatch flags");
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PutEvent(event);
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}
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return NS_OK;
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}
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NS_IMETHODIMP
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nsThreadPool::IsOnCurrentThread(bool *result)
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{
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// No one should be calling this method. If this assertion gets hit, then we
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// need to think carefully about what this method should be returning.
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NS_NOTREACHED("implement me");
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*result = false;
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return NS_OK;
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}
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NS_IMETHODIMP
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nsThreadPool::Shutdown()
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{
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nsCOMArray<nsIThread> threads;
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nsCOMPtr<nsIThreadPoolListener> listener;
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{
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ReentrantMonitorAutoEnter mon(mEvents.GetReentrantMonitor());
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mShutdown = true;
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mon.NotifyAll();
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threads.AppendObjects(mThreads);
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mThreads.Clear();
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// Swap in a null listener so that we release the listener at the end of
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// this method. The listener will be kept alive as long as the other threads
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// that were created when it was set.
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mListener.swap(listener);
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}
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// It's important that we shutdown the threads while outside the event queue
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// monitor. Otherwise, we could end up dead-locking.
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for (PRInt32 i = 0; i < threads.Count(); ++i)
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threads[i]->Shutdown();
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return NS_OK;
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}
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NS_IMETHODIMP
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nsThreadPool::GetThreadLimit(PRUint32 *value)
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{
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*value = mThreadLimit;
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return NS_OK;
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}
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NS_IMETHODIMP
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nsThreadPool::SetThreadLimit(PRUint32 value)
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{
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ReentrantMonitorAutoEnter mon(mEvents.GetReentrantMonitor());
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mThreadLimit = value;
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if (mIdleThreadLimit > mThreadLimit)
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mIdleThreadLimit = mThreadLimit;
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mon.NotifyAll(); // wake up threads so they observe this change
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return NS_OK;
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}
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NS_IMETHODIMP
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nsThreadPool::GetIdleThreadLimit(PRUint32 *value)
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{
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*value = mIdleThreadLimit;
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return NS_OK;
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}
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NS_IMETHODIMP
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nsThreadPool::SetIdleThreadLimit(PRUint32 value)
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{
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ReentrantMonitorAutoEnter mon(mEvents.GetReentrantMonitor());
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mIdleThreadLimit = value;
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if (mIdleThreadLimit > mThreadLimit)
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mIdleThreadLimit = mThreadLimit;
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mon.NotifyAll(); // wake up threads so they observe this change
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return NS_OK;
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}
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NS_IMETHODIMP
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nsThreadPool::GetIdleThreadTimeout(PRUint32 *value)
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{
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*value = mIdleThreadTimeout;
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return NS_OK;
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}
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NS_IMETHODIMP
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nsThreadPool::SetIdleThreadTimeout(PRUint32 value)
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{
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ReentrantMonitorAutoEnter mon(mEvents.GetReentrantMonitor());
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mIdleThreadTimeout = value;
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mon.NotifyAll(); // wake up threads so they observe this change
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return NS_OK;
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}
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NS_IMETHODIMP
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nsThreadPool::GetListener(nsIThreadPoolListener** aListener)
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{
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ReentrantMonitorAutoEnter mon(mEvents.GetReentrantMonitor());
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NS_IF_ADDREF(*aListener = mListener);
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return NS_OK;
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}
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NS_IMETHODIMP
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nsThreadPool::SetListener(nsIThreadPoolListener* aListener)
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{
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nsCOMPtr<nsIThreadPoolListener> swappedListener(aListener);
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{
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ReentrantMonitorAutoEnter mon(mEvents.GetReentrantMonitor());
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mListener.swap(swappedListener);
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}
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return NS_OK;
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}
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NS_IMETHODIMP
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nsThreadPool::SetName(const nsACString& aName)
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{
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{
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ReentrantMonitorAutoEnter mon(mEvents.GetReentrantMonitor());
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if (mThreads.Count())
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return NS_ERROR_NOT_AVAILABLE;
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}
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mName = aName;
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return NS_OK;
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}
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