xpcom/build/IOInterposerPrivate.h
author Birunthan Mohanathas <birunthan@mohanathas.com>
Wed, 13 Aug 2014 11:45:37 -0700
changeset 220983 4399b34c52596fe8828d2506a02e641f4c878813
parent 219566 64249d8c98148a2bc993e2c9fd1a160582b0a7ad
child 505383 6f3709b3878117466168c40affa7bca0b60cf75b
permissions -rw-r--r--
Bug 1046841 - Convert xpcom/build/ to Gecko style. r=froydnj

/* -*- 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 xpcom_build_IOInterposerPrivate_h
#define xpcom_build_IOInterposerPrivate_h

/* This header file contains declarations for helper classes that are
   to be used exclusively by IOInterposer and its observers. This header
   file is not to be used by anything else and MUST NOT be exported! */

#include <prcvar.h>
#include <prlock.h>

namespace mozilla {
namespace IOInterposer {

/**
 * The following classes are simple wrappers for PRLock and PRCondVar.
 * IOInterposer and friends use these instead of Mozilla::Mutex et al because
 * of the fact that IOInterposer is permitted to run until the process
 * terminates; we can't use anything that plugs into leak checkers or deadlock
 * detectors because IOInterposer will outlive those and generate false
 * positives.
 */

class Monitor
{
public:
  Monitor()
    : mLock(PR_NewLock())
    , mCondVar(PR_NewCondVar(mLock))
  {
  }

  ~Monitor()
  {
    PR_DestroyCondVar(mCondVar);
    mCondVar = nullptr;
    PR_DestroyLock(mLock);
    mLock = nullptr;
  }

  void Lock()
  {
    PR_Lock(mLock);
  }

  void Unlock()
  {
    PR_Unlock(mLock);
  }

  bool Wait(PRIntervalTime aTimeout = PR_INTERVAL_NO_TIMEOUT)
  {
    return PR_WaitCondVar(mCondVar, aTimeout) == PR_SUCCESS;
  }

  bool Notify()
  {
    return PR_NotifyCondVar(mCondVar) == PR_SUCCESS;
  }

private:
  PRLock*    mLock;
  PRCondVar* mCondVar;
};

class MonitorAutoLock
{
public:
  explicit MonitorAutoLock(Monitor& aMonitor)
    : mMonitor(aMonitor)
  {
    mMonitor.Lock();
  }

  ~MonitorAutoLock()
  {
    mMonitor.Unlock();
  }

  bool Wait(PRIntervalTime aTimeout = PR_INTERVAL_NO_TIMEOUT)
  {
    return mMonitor.Wait(aTimeout);
  }

  bool Notify()
  {
    return mMonitor.Notify();
  }

private:
  Monitor&  mMonitor;
};

class MonitorAutoUnlock
{
public:
  explicit MonitorAutoUnlock(Monitor& aMonitor)
    : mMonitor(aMonitor)
  {
    mMonitor.Unlock();
  }

  ~MonitorAutoUnlock()
  {
    mMonitor.Lock();
  }

private:
  Monitor&  mMonitor;
};

class Mutex
{
public:
  Mutex()
    : mPRLock(PR_NewLock())
  {
  }

  ~Mutex()
  {
    PR_DestroyLock(mPRLock);
    mPRLock = nullptr;
  }

  void Lock()
  {
    PR_Lock(mPRLock);
  }

  void Unlock()
  {
    PR_Unlock(mPRLock);
  }

private:
  PRLock*   mPRLock;
};

class AutoLock
{
public:
  explicit AutoLock(Mutex& aLock)
    : mLock(aLock)
  {
    mLock.Lock();
  }

  ~AutoLock()
  {
    mLock.Unlock();
  }

private:
  Mutex&     mLock;
};

} // namespace IOInterposer
} // namespace mozilla

#endif // xpcom_build_IOInterposerPrivate_h