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/*
* Copyright (C) 2016 Konstantin Tokavev <annulen@yandex.ru>
* Copyright (C) 2016 Yusuke Suzuki <utatane.tea@gmail.com>
*
* 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 <wtf/RunLoop.h>
namespace WTF {
class RunLoop::TimerBase::ScheduledTask : public ThreadSafeRefCounted<ScheduledTask> {
WTF_MAKE_NONCOPYABLE(ScheduledTask);
public:
static Ref<ScheduledTask> create(Function<void()>&& function, Seconds interval, bool repeating)
{
return adoptRef(*new ScheduledTask(WTFMove(function), interval, repeating));
}
ScheduledTask(Function<void()>&& function, Seconds interval, bool repeating)
: m_function(WTFMove(function))
, m_fireInterval(interval)
, m_isRepeating(repeating)
{
updateReadyTime();
}
bool fired()
{
if (!isActive())
return false;
m_function();
if (!m_isRepeating)
return false;
updateReadyTime();
return isActive();
}
MonotonicTime scheduledTimePoint() const
{
return m_scheduledTimePoint;
}
void updateReadyTime()
{
m_scheduledTimePoint = MonotonicTime::now();
if (!m_fireInterval)
return;
m_scheduledTimePoint += m_fireInterval;
}
struct EarliestSchedule {
bool operator()(const RefPtr<ScheduledTask>& lhs, const RefPtr<ScheduledTask>& rhs)
{
return lhs->scheduledTimePoint() > rhs->scheduledTimePoint();
}
};
bool isActive() const
{
return m_isActive.load();
}
void deactivate()
{
m_isActive.store(false);
}
private:
Function<void ()> m_function;
MonotonicTime m_scheduledTimePoint;
Seconds m_fireInterval;
std::atomic<bool> m_isActive { true };
bool m_isRepeating;
};
RunLoop::RunLoop()
{
}
RunLoop::~RunLoop()
{
LockHolder locker(m_loopLock);
m_shutdown = true;
m_readyToRun.notifyOne();
// Here is running main loops. Wait until all the main loops are destroyed.
if (!m_mainLoops.isEmpty())
m_stopCondition.wait(m_loopLock);
}
inline bool RunLoop::populateTasks(RunMode runMode, Status& statusOfThisLoop, Deque<RefPtr<TimerBase::ScheduledTask>>& firedTimers)
{
LockHolder locker(m_loopLock);
if (runMode == RunMode::Drain) {
MonotonicTime sleepUntil = MonotonicTime::infinity();
if (!m_schedules.isEmpty())
sleepUntil = m_schedules.first()->scheduledTimePoint();
m_readyToRun.waitUntil(m_loopLock, sleepUntil, [&] {
return m_shutdown || m_pendingTasks || statusOfThisLoop == Status::Stopping;
});
}
if (statusOfThisLoop == Status::Stopping || m_shutdown) {
m_mainLoops.removeLast();
if (m_mainLoops.isEmpty())
m_stopCondition.notifyOne();
return false;
}
m_pendingTasks = false;
if (runMode == RunMode::Iterate)
statusOfThisLoop = Status::Stopping;
// Check expired timers.
MonotonicTime now = MonotonicTime::now();
while (!m_schedules.isEmpty()) {
RefPtr<TimerBase::ScheduledTask> earliest = m_schedules.first();
if (earliest->scheduledTimePoint() > now)
break;
std::pop_heap(m_schedules.begin(), m_schedules.end(), TimerBase::ScheduledTask::EarliestSchedule());
m_schedules.removeLast();
firedTimers.append(WTFMove(earliest));
}
return true;
}
void RunLoop::runImpl(RunMode runMode)
{
ASSERT(this == &RunLoop::current());
Status statusOfThisLoop = Status::Clear;
{
LockHolder locker(m_loopLock);
m_mainLoops.append(&statusOfThisLoop);
}
Deque<RefPtr<TimerBase::ScheduledTask>> firedTimers;
while (true) {
if (!populateTasks(runMode, statusOfThisLoop, firedTimers))
return;
// Dispatch scheduled timers.
while (!firedTimers.isEmpty()) {
RefPtr<TimerBase::ScheduledTask> task = firedTimers.takeFirst();
if (task->fired()) {
// Reschedule because the timer requires repeating.
// Since we will query the timers' time points before sleeping,
// we do not call wakeUp() here.
schedule(*task);
}
}
performWork();
}
}
void RunLoop::run()
{
RunLoop::current().runImpl(RunMode::Drain);
}
void RunLoop::iterate()
{
RunLoop::current().runImpl(RunMode::Iterate);
}
// RunLoop operations are thread-safe. These operations can be called from outside of the RunLoop's thread.
// For example, WorkQueue::{dispatch, dispatchAfter} call the operations of the WorkQueue thread's RunLoop
// from the caller's thread.
void RunLoop::stop()
{
LockHolder locker(m_loopLock);
if (m_mainLoops.isEmpty())
return;
Status* status = m_mainLoops.last();
if (*status != Status::Stopping) {
*status = Status::Stopping;
m_readyToRun.notifyOne();
}
}
void RunLoop::wakeUp(const AbstractLocker&)
{
m_pendingTasks = true;
m_readyToRun.notifyOne();
}
void RunLoop::wakeUp()
{
LockHolder locker(m_loopLock);
wakeUp(locker);
}
RunLoop::CycleResult RunLoop::cycle(RunLoopMode)
{
iterate();
return CycleResult::Continue;
}
void RunLoop::schedule(const AbstractLocker&, Ref<TimerBase::ScheduledTask>&& task)
{
m_schedules.append(task.ptr());
std::push_heap(m_schedules.begin(), m_schedules.end(), TimerBase::ScheduledTask::EarliestSchedule());
}
void RunLoop::schedule(Ref<TimerBase::ScheduledTask>&& task)
{
LockHolder locker(m_loopLock);
schedule(locker, WTFMove(task));
}
void RunLoop::scheduleAndWakeUp(const AbstractLocker& locker, Ref<TimerBase::ScheduledTask>&& task)
{
schedule(locker, WTFMove(task));
wakeUp(locker);
}
void RunLoop::dispatchAfter(Seconds delay, Function<void()>&& function)
{
LockHolder locker(m_loopLock);
bool repeating = false;
schedule(locker, TimerBase::ScheduledTask::create(WTFMove(function), delay, repeating));
wakeUp(locker);
}
// Since RunLoop does not own the registered TimerBase,
// TimerBase and its owner should manage these lifetime.
RunLoop::TimerBase::TimerBase(RunLoop& runLoop)
: m_runLoop(runLoop)
, m_scheduledTask(nullptr)
{
}
RunLoop::TimerBase::~TimerBase()
{
LockHolder locker(m_runLoop->m_loopLock);
stop(locker);
}
void RunLoop::TimerBase::start(Seconds interval, bool repeating)
{
LockHolder locker(m_runLoop->m_loopLock);
stop(locker);
m_scheduledTask = ScheduledTask::create([this] {
fired();
}, interval, repeating);
m_runLoop->scheduleAndWakeUp(locker, *m_scheduledTask);
}
void RunLoop::TimerBase::stop(const AbstractLocker&)
{
if (m_scheduledTask) {
m_scheduledTask->deactivate();
m_scheduledTask = nullptr;
}
}
void RunLoop::TimerBase::stop()
{
LockHolder locker(m_runLoop->m_loopLock);
stop(locker);
}
bool RunLoop::TimerBase::isActive() const
{
LockHolder locker(m_runLoop->m_loopLock);
return isActive(locker);
}
bool RunLoop::TimerBase::isActive(const AbstractLocker&) const
{
return m_scheduledTask;
}
Seconds RunLoop::TimerBase::secondsUntilFire() const
{
LockHolder locker(m_runLoop->m_loopLock);
if (isActive(locker))
return std::max<Seconds>(m_scheduledTask->scheduledTimePoint() - MonotonicTime::now(), 0_s);
return 0_s;
}
} // namespace WTF