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author | Steve Block <steveblock@google.com> | 2011-05-06 11:45:16 +0100 |
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committer | Steve Block <steveblock@google.com> | 2011-05-12 13:44:10 +0100 |
commit | cad810f21b803229eb11403f9209855525a25d57 (patch) | |
tree | 29a6fd0279be608e0fe9ffe9841f722f0f4e4269 /Source/WebCore/platform/ThreadTimers.cpp | |
parent | 121b0cf4517156d0ac5111caf9830c51b69bae8f (diff) | |
download | external_webkit-cad810f21b803229eb11403f9209855525a25d57.zip external_webkit-cad810f21b803229eb11403f9209855525a25d57.tar.gz external_webkit-cad810f21b803229eb11403f9209855525a25d57.tar.bz2 |
Merge WebKit at r75315: Initial merge by git.
Change-Id: I570314b346ce101c935ed22a626b48c2af266b84
Diffstat (limited to 'Source/WebCore/platform/ThreadTimers.cpp')
-rw-r--r-- | Source/WebCore/platform/ThreadTimers.cpp | 132 |
1 files changed, 132 insertions, 0 deletions
diff --git a/Source/WebCore/platform/ThreadTimers.cpp b/Source/WebCore/platform/ThreadTimers.cpp new file mode 100644 index 0000000..3ae8207 --- /dev/null +++ b/Source/WebCore/platform/ThreadTimers.cpp @@ -0,0 +1,132 @@ +/* + * 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 + |