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/*
* Copyright (C) 2006-2016 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 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 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 "MainThreadSharedTimer.h"
#include "SharedTimer.h"
#include "ThreadGlobalData.h"
#include "Timer.h"
#include <wtf/ApproximateTime.h>
#include <wtf/MainThread.h>
#include <wtf/TZoneMallocInlines.h>
#if PLATFORM(IOS_FAMILY)
#include "WebCoreThread.h"
#endif
namespace WebCore {
WTF_MAKE_TZONE_ALLOCATED_IMPL(ThreadTimers);
// 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.
ThreadTimers::ThreadTimers()
{
if (isUIThread())
setSharedTimer(&MainThreadSharedTimer::singleton());
}
// A worker thread may initialize SharedTimer after some timers are created.
// Also, SharedTimer can be replaced with nullptr before all timers are destroyed.
void ThreadTimers::setSharedTimer(SharedTimer* sharedTimer)
{
if (m_sharedTimer) {
m_sharedTimer->setFiredFunction(nullptr);
m_sharedTimer->stop();
m_pendingSharedTimerFireTime = MonotonicTime { };
}
m_sharedTimer = sharedTimer;
if (sharedTimer) {
m_sharedTimer->setFiredFunction([] { threadGlobalData().threadTimers().sharedTimerFiredInternal(); });
updateSharedTimer();
}
}
void ThreadTimers::updateSharedTimer()
{
if (!m_sharedTimer)
return;
while (!m_timerHeap.isEmpty() && !m_timerHeap.first()->hasTimer()) {
ASSERT_NOT_REACHED();
TimerBase::heapDeleteNullMin(m_timerHeap);
}
ASSERT(m_timerHeap.isEmpty() || m_timerHeap.first()->hasTimer());
if (m_firingTimers || m_timerHeap.isEmpty()) {
m_pendingSharedTimerFireTime = MonotonicTime { };
m_sharedTimer->stop();
} else {
MonotonicTime nextFireTime = m_timerHeap.first()->time;
MonotonicTime currentMonotonicTime = MonotonicTime::now();
if (m_pendingSharedTimerFireTime) {
// No need to restart the timer if both the pending fire time and the new fire time are in the past.
if (m_pendingSharedTimerFireTime <= currentMonotonicTime && nextFireTime <= currentMonotonicTime)
return;
}
m_pendingSharedTimerFireTime = nextFireTime;
m_sharedTimer->setFireInterval(std::max(nextFireTime - currentMonotonicTime, 0_s));
}
}
void ThreadTimers::sharedTimerFiredInternal()
{
ASSERT(isMainThread() || (!isWebThread() && !isUIThread()));
// Do a re-entrancy check.
if (m_firingTimers)
return;
m_firingTimers = true;
m_pendingSharedTimerFireTime = MonotonicTime { };
auto fireTime = MonotonicTime::now();
auto timeToQuit = ApproximateTime::now() + maxDurationOfFiringTimers;
while (!m_timerHeap.isEmpty()) {
Ref<ThreadTimerHeapItem> item = *m_timerHeap.first();
ASSERT(item->hasTimer());
if (!item->hasTimer()) {
TimerBase::heapDeleteNullMin(m_timerHeap);
continue;
}
if (item->time > fireTime)
break;
auto& timer = item->timer();
Seconds interval = timer.repeatInterval();
timer.setNextFireTime(interval ? fireTime + interval : MonotonicTime { });
// Once the timer has been fired, it may be deleted, so do nothing else with it after this point.
item->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 < ApproximateTime::now())
break;
if (m_shouldBreakFireLoopForRenderingUpdate)
break;
}
m_firingTimers = false;
m_shouldBreakFireLoopForRenderingUpdate = false;
updateSharedTimer();
}
void ThreadTimers::fireTimersInNestedEventLoop()
{
// Reset the reentrancy guard so the timers can fire again.
m_firingTimers = false;
if (m_sharedTimer) {
m_sharedTimer->invalidate();
m_pendingSharedTimerFireTime = MonotonicTime { };
}
updateSharedTimer();
}
void ThreadTimers::breakFireLoopForRenderingUpdate()
{
if (!m_firingTimers)
return;
m_shouldBreakFireLoopForRenderingUpdate = true;
}
} // namespace WebCore
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