criticalsection.h

由GOOGLE的JINGLE项目中移植的网络库

/*
 * libjingle
 * Copyright 2004--2005, Google Inc.
 *
 * 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.
 *  3. The name of the author may not be used to endorse or promote products 
 *     derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 THE AUTHOR 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 _criticalsection_h_
#define _criticalsection_h_

#include "win32.h"

#ifdef _DEBUG
#define CS_TRACK_OWNER 1
#endif  // _DEBUG

#if CS_TRACK_OWNER
#define TRACK_OWNER(x) x
#else  // !CS_TRACK_OWNER
#define TRACK_OWNER(x)
#endif  // !CS_TRACK_OWNER

namespace cricket {

class CriticalSection {
public:
  CriticalSection() {
    InitializeCriticalSection(&crit_);
    // Windows docs say 0 is not a valid thread id
    TRACK_OWNER(thread_ = 0);
  }
  ~CriticalSection() {
    DeleteCriticalSection(&crit_);
  }
  void Enter() {
    EnterCriticalSection(&crit_);
    TRACK_OWNER(thread_ = GetCurrentThreadId());
  }
  void Leave() {
    TRACK_OWNER(thread_ = 0);
    LeaveCriticalSection(&crit_);
  }

#if CS_TRACK_OWNER
  bool CurrentThreadIsOwner() const { return thread_ == GetCurrentThreadId(); }
#endif  // CS_TRACK_OWNER

private:
  CRITICAL_SECTION crit_;
  TRACK_OWNER(DWORD thread_);  // The section's owning thread id
};


// CritScope, for serializing exection through a scope

class CritScope {
public:
  CritScope(CriticalSection *pcrit) {
    pcrit_ = pcrit;
    pcrit_->Enter();
  }
  ~CritScope() {
    pcrit_->Leave();
  }
private:
  CriticalSection *pcrit_;
};

} // namespace cricket

#endif // _criticalsection_h_