gecko-dev/xpcom/threads/nsEventQueue.cpp

142 lines
4.0 KiB
C++

/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim:set ts=2 sw=2 sts=2 et cindent: */
/* ***** BEGIN LICENSE BLOCK *****
* Version: MPL 1.1/GPL 2.0/LGPL 2.1
*
* The contents of this file are subject to the Mozilla Public License Version
* 1.1 (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
* http://www.mozilla.org/MPL/
*
* Software distributed under the License is distributed on an "AS IS" basis,
* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
* for the specific language governing rights and limitations under the
* License.
*
* The Original Code is Mozilla code.
*
* The Initial Developer of the Original Code is Google Inc.
* Portions created by the Initial Developer are Copyright (C) 2006
* the Initial Developer. All Rights Reserved.
*
* Contributor(s):
* Darin Fisher <darin@meer.net>
*
* Alternatively, the contents of this file may be used under the terms of
* either the GNU General Public License Version 2 or later (the "GPL"), or
* the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
* in which case the provisions of the GPL or the LGPL are applicable instead
* of those above. If you wish to allow use of your version of this file only
* under the terms of either the GPL or the LGPL, and not to allow others to
* use your version of this file under the terms of the MPL, indicate your
* decision by deleting the provisions above and replace them with the notice
* and other provisions required by the GPL or the LGPL. If you do not delete
* the provisions above, a recipient may use your version of this file under
* the terms of any one of the MPL, the GPL or the LGPL.
*
* ***** END LICENSE BLOCK ***** */
#include "nsEventQueue.h"
#include "nsAutoLock.h"
#include "nsAutoPtr.h"
#include "prlog.h"
#include "nsThreadUtils.h"
#ifdef PR_LOGGING
static PRLogModuleInfo *sLog = PR_NewLogModule("nsEventQueue");
#endif
#define LOG(args) PR_LOG(sLog, PR_LOG_DEBUG, args)
nsEventQueue::nsEventQueue()
: mMonitor(nsAutoMonitor::NewMonitor("xpcom.eventqueue"))
, mHead(nsnull)
, mTail(nsnull)
, mOffsetHead(0)
, mOffsetTail(0)
{
}
nsEventQueue::~nsEventQueue()
{
// It'd be nice to be able to assert that no one else is holding the monitor,
// but NSPR doesn't really expose APIs for it.
NS_ASSERTION(IsEmpty(), "Non-empty event queue being destroyed; events being leaked.");
if (mHead)
FreePage(mHead);
if (mMonitor)
nsAutoMonitor::DestroyMonitor(mMonitor);
}
PRBool
nsEventQueue::GetEvent(PRBool mayWait, nsIRunnable **result)
{
{
nsAutoMonitor mon(mMonitor);
while (IsEmpty()) {
if (!mayWait) {
if (result)
*result = nsnull;
return PR_FALSE;
}
LOG(("EVENTQ(%p): wait begin\n", this));
mon.Wait();
LOG(("EVENTQ(%p): wait end\n", this));
}
if (result) {
*result = mHead->mEvents[mOffsetHead++];
// Check if mHead points to empty Page
if (mOffsetHead == EVENTS_PER_PAGE) {
Page *dead = mHead;
mHead = mHead->mNext;
FreePage(dead);
mOffsetHead = 0;
}
}
}
return PR_TRUE;
}
PRBool
nsEventQueue::PutEvent(nsIRunnable *runnable)
{
// Avoid calling AddRef+Release while holding our monitor.
nsRefPtr<nsIRunnable> event(runnable);
PRBool rv = PR_TRUE;
{
nsAutoMonitor mon(mMonitor);
if (!mHead) {
mHead = NewPage();
if (!mHead) {
rv = PR_FALSE;
} else {
mTail = mHead;
mOffsetHead = 0;
mOffsetTail = 0;
}
} else if (mOffsetTail == EVENTS_PER_PAGE) {
Page *page = NewPage();
if (!page) {
rv = PR_FALSE;
} else {
mTail->mNext = page;
mTail = page;
mOffsetTail = 0;
}
}
if (rv) {
event.swap(mTail->mEvents[mOffsetTail]);
++mOffsetTail;
LOG(("EVENTQ(%p): notify\n", this));
mon.NotifyAll();
}
}
return rv;
}