////////////////////////////////////////////////////////////////////////////////
/// @brief Mutex Locker
///
/// @file
///
/// DISCLAIMER
///
/// Copyright 2014 ArangoDB GmbH, Cologne, Germany
/// Copyright 2004-2014 triAGENS GmbH, Cologne, Germany
///
/// Licensed under the Apache License, Version 2.0 (the "License");
/// you may not use this file except in compliance with the License.
/// You may obtain a copy of the License at
///
///     http://www.apache.org/licenses/LICENSE-2.0
///
/// Unless required by applicable law or agreed to in writing, software
/// distributed under the License is distributed on an "AS IS" BASIS,
/// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
/// See the License for the specific language governing permissions and
/// limitations under the License.
///
/// Copyright holder is ArangoDB GmbH, Cologne, Germany
///
/// @author Dr. Frank Celler
/// @author Achim Brandt
/// @author Copyright 2014, ArangoDB GmbH, Cologne, Germany
/// @author Copyright 2008-2013, triAGENS GmbH, Cologne, Germany
////////////////////////////////////////////////////////////////////////////////

#ifndef ARANGODB_BASICS_MUTEX_LOCKER_H
#define ARANGODB_BASICS_MUTEX_LOCKER_H 1

#include "Basics/Common.h"
#include "Basics/Mutex.h"

// -----------------------------------------------------------------------------
// --SECTION--                                                     public macros
// -----------------------------------------------------------------------------

////////////////////////////////////////////////////////////////////////////////
/// @brief construct locker with file and line information
///
/// Ones needs to use macros twice to get a unique variable based on the line
/// number.
////////////////////////////////////////////////////////////////////////////////

#define MUTEX_LOCKER_VAR_A(a) _mutex_lock_variable_ ## a
#define MUTEX_LOCKER_VAR_B(a) MUTEX_LOCKER_VAR_A(a)

#ifdef TRI_SHOW_LOCK_TIME

#define MUTEX_LOCKER(b) \
  triagens::basics::MutexLocker MUTEX_LOCKER_VAR_B(__LINE__)(&b, __FILE__, __LINE__)

#else

#define MUTEX_LOCKER(b) \
  triagens::basics::MutexLocker MUTEX_LOCKER_VAR_B(__LINE__)(&b)

#endif

// -----------------------------------------------------------------------------
// --SECTION--                                                 class MutexLocker
// -----------------------------------------------------------------------------

namespace triagens {
  namespace basics {

////////////////////////////////////////////////////////////////////////////////
/// @brief mutex locker
///
/// A MutexLocker locks a mutex during its lifetime und unlocks the mutex
/// when it is destroyed.
////////////////////////////////////////////////////////////////////////////////

    class MutexLocker {
        MutexLocker (MutexLocker const&);
        MutexLocker& operator= (MutexLocker const&);

// -----------------------------------------------------------------------------
// --SECTION--                                      constructors and destructors
// -----------------------------------------------------------------------------

      public:

////////////////////////////////////////////////////////////////////////////////
/// @brief aquires a lock
///
/// The constructor aquires a lock, the destructor releases the lock.
////////////////////////////////////////////////////////////////////////////////

#ifdef TRI_SHOW_LOCK_TIME

        MutexLocker (Mutex* mutex, char const* file, int line);

#else

        explicit
        MutexLocker (Mutex* mutex);

#endif        

////////////////////////////////////////////////////////////////////////////////
/// @brief releases the lock
////////////////////////////////////////////////////////////////////////////////

        ~MutexLocker ();

// -----------------------------------------------------------------------------
// --SECTION--                                                 private variables
// -----------------------------------------------------------------------------

      private:

////////////////////////////////////////////////////////////////////////////////
/// @brief the mutex
////////////////////////////////////////////////////////////////////////////////

        Mutex* _mutex;

#ifdef TRI_SHOW_LOCK_TIME

////////////////////////////////////////////////////////////////////////////////
/// @brief file
////////////////////////////////////////////////////////////////////////////////

        char const* _file;

////////////////////////////////////////////////////////////////////////////////
/// @brief line number
////////////////////////////////////////////////////////////////////////////////

        int _line;

////////////////////////////////////////////////////////////////////////////////
/// @brief lock time
////////////////////////////////////////////////////////////////////////////////

        double _time;

#endif        
    };
  }
}

#endif

// -----------------------------------------------------------------------------
// --SECTION--                                                       END-OF-FILE
// -----------------------------------------------------------------------------

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