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// Copyright 2014 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef COMPONENTS_TIMER_ALARM_TIMER_H_
#define COMPONENTS_TIMER_ALARM_TIMER_H_
#include "base/callback.h"
#include "base/macros.h"
#include "base/memory/ref_counted.h"
#include "base/memory/weak_ptr.h"
#include "base/message_loop/message_loop.h"
#include "base/time/time.h"
#include "base/timer/timer.h"
namespace base {
struct PendingTask;
}
namespace timers {
// The class implements a timer that is capable of waking the system up from a
// suspended state. For example, this is useful for running tasks that are
// needed for maintaining network connectivity, like sending heartbeat messages.
// Currently, this feature is only available on Chrome OS systems running linux
// version 3.11 or higher. On all other platforms, the AlarmTimer behaves
// exactly the same way as a regular Timer.
class AlarmTimer : public base::Timer,
public base::MessageLoop::DestructionObserver {
public:
// The delegate is responsible for managing the system level details for
// actually setting up and monitoring a timer that is capable of waking the
// system from suspend. This class is reference counted because it may need
// to outlive the timer in order to clean up after itself.
class Delegate : public base::RefCountedThreadSafe<Delegate> {
public:
// Initializes the timer. Should return true iff the system has timers that
// can wake it up from suspend. Will only be called once.
virtual bool Init(base::WeakPtr<AlarmTimer> timer) = 0;
// Stops the currently running timer. It should be safe to call this more
// than once.
virtual void Stop() = 0;
// Resets the timer to fire after |delay| has passed. Cancels any
// pre-existing delay.
virtual void Reset(base::TimeDelta delay) = 0;
protected:
virtual ~Delegate() {}
private:
friend class base::RefCountedThreadSafe<Delegate>;
};
AlarmTimer(bool retain_user_task, bool is_repeating);
AlarmTimer(const tracked_objects::Location& posted_from,
base::TimeDelta delay,
const base::Closure& user_task,
bool is_repeating);
~AlarmTimer() override;
bool can_wake_from_suspend() const { return can_wake_from_suspend_; }
// Must be called by the delegate to indicate that the timer has fired and
// that the user task should be run.
void OnTimerFired();
// Timer overrides.
void Stop() override;
void Reset() override;
// MessageLoop::DestructionObserver overrides.
void WillDestroyCurrentMessageLoop() override;
private:
// Initializes the timer with the appropriate delegate.
void Init();
// Delegate that will manage actually setting the timer.
scoped_refptr<Delegate> delegate_;
// Keeps track of the user task we want to run. A new one is constructed
// every time Reset() is called.
scoped_ptr<base::PendingTask> pending_task_;
// Tracks whether the timer has the ability to wake the system up from
// suspend. This is a runtime check because we won't know if the system
// supports being woken up from suspend until the delegate actually tries to
// set it up.
bool can_wake_from_suspend_;
// Pointer to the message loop that started the timer. Used to track the
// destruction of that message loop.
base::MessageLoop* origin_message_loop_;
base::WeakPtrFactory<AlarmTimer> weak_factory_;
DISALLOW_COPY_AND_ASSIGN(AlarmTimer);
};
} // namespace timers
#endif // COMPONENTS_TIMER_ALARM_TIMER_H_
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