/* -*- 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 mozilla_Monitor_h

#define mozilla_Monitor_h

#include "mozilla/CondVar.h"

#include "mozilla/Mutex.h"

namespace mozilla {

/**

 * Monitor provides a *non*-reentrant monitor: *not* a Java-style

 * monitor.  If your code needs support for reentrancy, use

 * ReentrantMonitor instead.  (Rarely should reentrancy be needed.)

 *

 * Instead of directly calling Monitor methods, it's safer and simpler

 * to instead use the RAII wrappers MonitorAutoLock and

 * MonitorAutoUnlock.

 */

class Monitor

{

public:

  explicit Monitor(const char* aName,

                   recordreplay::Behavior aRecorded = recordreplay::Behavior::Preserve)

    : mMutex(aName, aRecorded)

    , mCondVar(mMutex, "[Monitor.mCondVar]")

  {

  }

  ~Monitor() {}

  void Lock() { mMutex.Lock(); }

  void Unlock() { mMutex.Unlock(); }

  void Wait() { mCondVar.Wait(); }

  CVStatus Wait(TimeDuration aDuration) { return mCondVar.Wait(aDuration); }

  nsresult Notify() { return mCondVar.Notify(); }

  nsresult NotifyAll() { return mCondVar.NotifyAll(); }

  void AssertCurrentThreadOwns() const

  {

    mMutex.AssertCurrentThreadOwns();

  }

  void AssertNotCurrentThreadOwns() const

  {

    mMutex.AssertNotCurrentThreadOwns();

  }

private:

  Monitor();

  Monitor(const Monitor&);

  Monitor& operator=(const Monitor&);

  Mutex mMutex;

  CondVar mCondVar;

};

/**

 * Lock the monitor for the lexical scope instances of this class are

 * bound to (except for MonitorAutoUnlock in nested scopes).

 *

 * The monitor must be unlocked when instances of this class are

 * created.

 */

class MOZ_STACK_CLASS MonitorAutoLock

{

public:

  explicit MonitorAutoLock(Monitor& aMonitor)

    : mMonitor(&aMonitor)

  {

    mMonitor->Lock();

  }

  ~MonitorAutoLock()

  {

    mMonitor->Unlock();

  }

  void Wait() { mMonitor->Wait(); }

  CVStatus Wait(TimeDuration aDuration) { return mMonitor->Wait(aDuration); }

  nsresult Notify() { return mMonitor->Notify(); }

  nsresult NotifyAll() { return mMonitor->NotifyAll(); }

private:

  MonitorAutoLock();

  MonitorAutoLock(const MonitorAutoLock&);

  MonitorAutoLock& operator=(const MonitorAutoLock&);

  static void* operator new(size_t) CPP_THROW_NEW;

  friend class MonitorAutoUnlock;

  Monitor* mMonitor;

};

/**

 * Unlock the monitor for the lexical scope instances of this class

 * are bound to (except for MonitorAutoLock in nested scopes).

 *

 * The monitor must be locked by the current thread when instances of

 * this class are created.

 */

class MOZ_STACK_CLASS MonitorAutoUnlock

{

public:

  explicit MonitorAutoUnlock(Monitor& aMonitor)

    : mMonitor(&aMonitor)

  {

    mMonitor->Unlock();

  }

  explicit MonitorAutoUnlock(MonitorAutoLock& aMonitorLock)

    : mMonitor(aMonitorLock.mMonitor)

  {

    mMonitor->Unlock();

  }

  ~MonitorAutoUnlock()

  {

    mMonitor->Lock();

  }

private:

  MonitorAutoUnlock();

  MonitorAutoUnlock(const MonitorAutoUnlock&);

  MonitorAutoUnlock& operator=(const MonitorAutoUnlock&);

  static void* operator new(size_t) CPP_THROW_NEW;

  Monitor* mMonitor;

};

} // namespace mozilla

#endif // mozilla_Monitor_h