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diff --git a/Source/WTF/wtf/generic/RunLoopGeneric.cpp b/Source/WTF/wtf/generic/RunLoopGeneric.cpp
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index 000000000..9a3c09a85
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+++ b/Source/WTF/wtf/generic/RunLoopGeneric.cpp
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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 "RunLoop.h"
+
+namespace WTF {
+
+class RunLoop::TimerBase::ScheduledTask : public ThreadSafeRefCounted<ScheduledTask> {
+WTF_MAKE_NONCOPYABLE(ScheduledTask);
+public:
+    static RefPtr<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(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(WTFMove(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 LockHolder&)
+{
+    m_pendingTasks = true;
+    m_readyToRun.notifyOne();
+}
+
+void RunLoop::wakeUp()
+{
+    LockHolder locker(m_loopLock);
+    wakeUp(locker);
+}
+
+void RunLoop::schedule(const LockHolder&, RefPtr<TimerBase::ScheduledTask>&& task)
+{
+    m_schedules.append(WTFMove(task));
+    std::push_heap(m_schedules.begin(), m_schedules.end(), TimerBase::ScheduledTask::EarliestSchedule());
+}
+
+void RunLoop::schedule(RefPtr<TimerBase::ScheduledTask>&& task)
+{
+    LockHolder locker(m_loopLock);
+    schedule(locker, WTFMove(task));
+}
+
+void RunLoop::scheduleAndWakeUp(RefPtr<TimerBase::ScheduledTask> task)
+{
+    LockHolder locker(m_loopLock);
+    schedule(locker, WTFMove(task));
+    wakeUp(locker);
+}
+
+void RunLoop::dispatchAfter(std::chrono::nanoseconds delay, Function<void ()>&& function)
+{
+    LockHolder locker(m_loopLock);
+    bool repeating = false;
+    schedule(locker, TimerBase::ScheduledTask::create(WTFMove(function), Seconds(delay.count() / 1000.0 / 1000.0 / 1000.0), repeating));
+    wakeUp(locker);
+}
+
+// Since RunLoop does not own the registered TimerBase,
+// TimerBase and its owner should manage these lifetime.
+//
+// And more importantly, TimerBase operations are not thread-safe.
+// So threads that do not belong to the ScheduledTask's RunLoop
+// should not operate the RunLoop::TimerBase.
+// This is the same to the RunLoopWin, which is RunLoop for Windows.
+RunLoop::TimerBase::TimerBase(RunLoop& runLoop)
+    : m_runLoop(runLoop)
+    , m_scheduledTask(nullptr)
+{
+}
+
+RunLoop::TimerBase::~TimerBase()
+{
+    stop();
+}
+
+void RunLoop::TimerBase::start(double interval, bool repeating)
+{
+    stop();
+    m_scheduledTask = ScheduledTask::create([this] {
+        fired();
+    }, Seconds(interval), repeating);
+    m_runLoop.scheduleAndWakeUp(m_scheduledTask);
+}
+
+void RunLoop::TimerBase::stop()
+{
+    if (m_scheduledTask) {
+        m_scheduledTask->deactivate();
+        m_scheduledTask = nullptr;
+    }
+}
+
+bool RunLoop::TimerBase::isActive() const
+{
+    return m_scheduledTask;
+}
+
+} // namespace WTF