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/*
* Copyright (C) 2010 Apple 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. AND ITS CONTRIBUTORS ``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 ITS 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.
*/
#ifndef ResponsivenessTimer_h
#define ResponsivenessTimer_h
#include <wtf/AbstractRefCountedAndCanMakeWeakPtr.h>
#include <wtf/RefCounted.h>
#include <wtf/RunLoop.h>
#include <wtf/WeakRef.h>
namespace WebKit {
class ResponsivenessTimer : public RefCounted<ResponsivenessTimer> {
WTF_MAKE_FAST_ALLOCATED;
public:
class Client : public AbstractRefCountedAndCanMakeWeakPtr<Client> {
public:
virtual ~Client() { }
virtual void didBecomeUnresponsive() = 0;
virtual void didBecomeResponsive() = 0;
virtual void willChangeIsResponsive() = 0;
virtual void didChangeIsResponsive() = 0;
virtual bool mayBecomeUnresponsive() = 0;
};
static constexpr Seconds defaultResponsivenessTimeout = 3_s;
static Ref<ResponsivenessTimer> create(ResponsivenessTimer::Client&, Seconds responsivenessTimeout);
~ResponsivenessTimer();
void start();
// A responsiveness timer with lazy stop does not stop the underlying system timer when stopped.
// Instead, it ignores the timeout if stop() was already called.
//
// This exists to reduce the rate at which we reset the timer.
//
// With a non lazy timer, we may set a timer and reset it soon after because the process is responsive.
// For events, this means reseting a timer 120 times/s for a 60 Hz event source.
// By not reseting the timer when responsive, we cut that in half to 60 timeout changes.
void startWithLazyStop();
void stop();
void invalidate();
// Return true if stop() was not called betfore the responsiveness timeout.
bool isResponsive() const { return m_isResponsive; }
// Return true if there is an active timer. The state could be responsive or not.
bool hasActiveTimer() const { return m_waitingForTimer; }
void processTerminated();
private:
ResponsivenessTimer(ResponsivenessTimer::Client&, Seconds responsivenessTimeout);
void timerFired();
bool mayBecomeUnresponsive() const;
WeakPtr<ResponsivenessTimer::Client> m_client;
RunLoop::Timer m_timer;
MonotonicTime m_restartFireTime;
bool m_isResponsive { true };
bool m_waitingForTimer { false };
bool m_useLazyStop { false };
Seconds m_responsivenessTimeout;
};
} // namespace WebKit
#endif // ResponsivenessTimer_h
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