Mutex.hpp

Go to the documentation of this file.

/*==========================================================================
 * Copyright (c) 2004 University of Massachusetts.  All Rights Reserved.
 *
 * Use of the Lemur Toolkit for Language Modeling and Information Retrieval
 * is subject to the terms of the software license set forth in the LICENSE
 * file included with this software, and also available at
 * http://www.lemurproject.org/license.html
 *
 *==========================================================================
 */

//
// Mutex
//
// 15 November 2004 -- tds
//

#ifndef INDRI_MUTEX_HPP
#define INDRI_MUTEX_HPP

#include <assert.h>

#ifndef WIN32
#include <pthread.h>
#else
#include "lemur-platform.h"
#endif

#include "indri/Lockable.hpp"
namespace indri
{
  namespace thread
  {
    
    class Mutex : public Lockable {
      friend class ConditionVariable;

    private:
#ifdef WIN32
      HANDLE _mutex;
#else // POSIX
      pthread_mutex_t _mutex;
#endif

      // make copy construction private
      explicit Mutex( Mutex& m ) {}

    public:
      Mutex() {
#ifdef WIN32
        _mutex = ::CreateMutex( NULL, FALSE, NULL );
#else
        pthread_mutex_init( &_mutex, NULL );
#endif
      }

      ~Mutex() {
#ifdef WIN32
        if( _mutex != INVALID_HANDLE_VALUE ) {
          ::CloseHandle( _mutex );
          _mutex = 0;
        }
#else
        pthread_mutex_destroy( &_mutex );
#endif
      }

      void lock() {
#ifdef WIN32
        ::WaitForSingleObject( _mutex, INFINITE );
#else
        int result = pthread_mutex_lock( &_mutex );
        assert( result == 0 );
#endif
      }

      bool tryLock() {
#ifdef WIN32
        HRESULT result = ::WaitForSingleObject( _mutex, 0 );
        return (result == WAIT_OBJECT_0) || (result == WAIT_ABANDONED);
#else
        return pthread_mutex_trylock( &_mutex ) == 0;
#endif
      }

      void unlock() {
#ifdef WIN32
        ::ReleaseMutex( _mutex );
#else
        int result = pthread_mutex_unlock( &_mutex );
        assert( result == 0 );
#endif
      }
    };
  }
}

#endif // INDRI_MUTEX_HPP

---