/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */

/* vim: set ts=8 sts=2 et sw=2 tw=80: */

/* This Source Code Form is subject to the terms of the Mozilla Public

 * License, v. 2.0. If a copy of the MPL was not distributed with this

 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#ifndef TimerThread_h___

#define TimerThread_h___

#include "nsIObserver.h"

#include "nsIRunnable.h"

#include "nsIThread.h"

#include "nsTimerImpl.h"

#include "nsThreadUtils.h"

#include "nsTArray.h"

#include "mozilla/Atomics.h"

#include "mozilla/Attributes.h"

#include "mozilla/Monitor.h"

#include "mozilla/UniquePtr.h"

#include <algorithm>

namespace mozilla {

class TimeStamp;

} // namespace mozilla

class TimerThread final

  : public nsIRunnable

  , public nsIObserver

{

public:

  typedef mozilla::Monitor Monitor;

  typedef mozilla::TimeStamp TimeStamp;

  typedef mozilla::TimeDuration TimeDuration;

  TimerThread();

  nsresult InitLocks();

  NS_DECL_THREADSAFE_ISUPPORTS

  NS_DECL_NSIRUNNABLE

  NS_DECL_NSIOBSERVER

  nsresult Shutdown();

  nsresult AddTimer(nsTimerImpl* aTimer);

  nsresult RemoveTimer(nsTimerImpl* aTimer);

  TimeStamp FindNextFireTimeForCurrentThread(TimeStamp aDefault, uint32_t aSearchBound);

  void DoBeforeSleep();

  void DoAfterSleep();

  bool IsOnTimerThread() const

  {

    return mThread->SerialEventTarget()->IsOnCurrentThread();

  }

  uint32_t

  AllowedEarlyFiringMicroseconds() const;

private:

  ~TimerThread();

  bool    mInitialized;

  // These internal helper methods must be called while mMonitor is held.

  // AddTimerInternal returns false if the insertion failed.

  bool    AddTimerInternal(nsTimerImpl* aTimer);

  bool    RemoveTimerInternal(nsTimerImpl* aTimer);

  void    RemoveLeadingCanceledTimersInternal();

  void    RemoveFirstTimerInternal();

  nsresult Init();

  already_AddRefed<nsTimerImpl> PostTimerEvent(already_AddRefed<nsTimerImpl> aTimerRef);

  nsCOMPtr<nsIThread> mThread;

  Monitor mMonitor;

  bool mShutdown;

  bool mWaiting;

  bool mNotified;

  bool mSleeping;

  class Entry final : public nsTimerImplHolder

  {

    const TimeStamp mTimeout;

  public:

    Entry(const TimeStamp& aMinTimeout, const TimeStamp& aTimeout,

          nsTimerImpl* aTimerImpl)

      : nsTimerImplHolder(aTimerImpl)

      , mTimeout(std::max(aMinTimeout, aTimeout))

    {

    }

    nsTimerImpl*

    Value() const

    {

      return mTimerImpl;

    }

    already_AddRefed<nsTimerImpl>

    Take()

    {

      if (mTimerImpl) {

        mTimerImpl->SetHolder(nullptr);

      }

      return mTimerImpl.forget();

    }

    static bool

    UniquePtrLessThan(mozilla::UniquePtr<Entry>& aLeft,

                      mozilla::UniquePtr<Entry>& aRight)

    {

      // This is reversed because std::push_heap() sorts the "largest" to

      // the front of the heap.  We want that to be the earliest timer.

      return aRight->mTimeout < aLeft->mTimeout;

    }

    TimeStamp Timeout() const

    {

      return mTimeout;

    }

  };

  nsTArray<mozilla::UniquePtr<Entry>> mTimers;

  uint32_t mAllowedEarlyFiringMicroseconds;

};

#endif /* TimerThread_h___ */