/* | |
* Copyright (C) 2006, 2008 Apple Inc. All rights reserved. | |
* Copyright (C) 2009 Google Inc. All rights reserved. | |
* | |
* Redistribution and use in source and binary forms, with or without | |
* modification, are permitted provided that the following conditions | |
* are met: | |
* 1. Redistributions of source code must retain the above copyright | |
* notice, this list of conditions and the following disclaimer. | |
* 2. Redistributions in binary form must reproduce the above copyright | |
* notice, this list of conditions and the following disclaimer in the | |
* documentation and/or other materials provided with the distribution. | |
* | |
* THIS SOFTWARE IS PROVIDED BY APPLE COMPUTER, INC. ``AS IS'' AND ANY | |
* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE | |
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR | |
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE COMPUTER, INC. OR | |
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, | |
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, | |
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR | |
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY | |
* OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT | |
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE | |
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. | |
*/ | |
#include "config.h" | |
#include "ThreadTimers.h" | |
#include "SharedTimer.h" | |
#include "ThreadGlobalData.h" | |
#include "Timer.h" | |
#include <wtf/CurrentTime.h> | |
namespace WebCore { | |
// Fire timers for this length of time, and then quit to let the run loop process user input events. | |
// 100ms is about a perceptable delay in UI, so use a half of that as a threshold. | |
// This is to prevent UI freeze when there are too many timers or machine performance is low. | |
static const double maxDurationOfFiringTimers = 0.050; | |
// Timers are created, started and fired on the same thread, and each thread has its own ThreadTimers | |
// copy to keep the heap and a set of currently firing timers. | |
static MainThreadSharedTimer* mainThreadSharedTimer() | |
{ | |
static MainThreadSharedTimer* timer = new MainThreadSharedTimer; | |
return timer; | |
} | |
ThreadTimers::ThreadTimers() | |
: m_sharedTimer(0) | |
, m_firingTimers(false) | |
{ | |
if (isMainThread()) | |
setSharedTimer(mainThreadSharedTimer()); | |
} | |
// A worker thread may initialize SharedTimer after some timers are created. | |
// Also, SharedTimer can be replaced with 0 before all timers are destroyed. | |
void ThreadTimers::setSharedTimer(SharedTimer* sharedTimer) | |
{ | |
if (m_sharedTimer) { | |
m_sharedTimer->setFiredFunction(0); | |
m_sharedTimer->stop(); | |
} | |
m_sharedTimer = sharedTimer; | |
if (sharedTimer) { | |
m_sharedTimer->setFiredFunction(ThreadTimers::sharedTimerFired); | |
updateSharedTimer(); | |
} | |
} | |
void ThreadTimers::updateSharedTimer() | |
{ | |
if (!m_sharedTimer) | |
return; | |
if (m_firingTimers || m_timerHeap.isEmpty()) | |
m_sharedTimer->stop(); | |
else | |
m_sharedTimer->setFireTime(m_timerHeap.first()->m_nextFireTime); | |
} | |
void ThreadTimers::sharedTimerFired() | |
{ | |
// Redirect to non-static method. | |
threadGlobalData().threadTimers().sharedTimerFiredInternal(); | |
} | |
void ThreadTimers::sharedTimerFiredInternal() | |
{ | |
// Do a re-entrancy check. | |
if (m_firingTimers) | |
return; | |
m_firingTimers = true; | |
double fireTime = currentTime(); | |
double timeToQuit = fireTime + maxDurationOfFiringTimers; | |
while (!m_timerHeap.isEmpty() && m_timerHeap.first()->m_nextFireTime <= fireTime) { | |
TimerBase* timer = m_timerHeap.first(); | |
timer->m_nextFireTime = 0; | |
timer->heapDeleteMin(); | |
double interval = timer->repeatInterval(); | |
timer->setNextFireTime(interval ? fireTime + interval : 0); | |
// Once the timer has been fired, it may be deleted, so do nothing else with it after this point. | |
timer->fired(); | |
// Catch the case where the timer asked timers to fire in a nested event loop, or we are over time limit. | |
if (!m_firingTimers || timeToQuit < currentTime()) | |
break; | |
} | |
m_firingTimers = false; | |
updateSharedTimer(); | |
} | |
void ThreadTimers::fireTimersInNestedEventLoop() | |
{ | |
// Reset the reentrancy guard so the timers can fire again. | |
m_firingTimers = false; | |
updateSharedTimer(); | |
} | |
} // namespace WebCore | |