/********************************************************************
**                Image Component Library (ICL)                    **
**                                                                 **
** Copyright (C) 2006-2012 CITEC, University of Bielefeld          **
**                         Neuroinformatics Group                  **
** Website: www.iclcv.org and                                      **
**          http://opensource.cit-ec.de/projects/icl               **
**                                                                 **
** File   : include/ICLUtils/Mutex.h                               **
** Module : ICLUtils                                               **
** Authors: Christof Elbrechter                                    **
**                                                                 **
**                                                                 **
** Commercial License                                              **
** ICL can be used commercially, please refer to our website       **
** www.iclcv.org for more details.                                 **
**                                                                 **
** GNU General Public License Usage                                **
** Alternatively, this file may be used under the terms of the     **
** GNU General Public License version 3.0 as published by the      **
** Free Software Foundation and appearing in the file LICENSE.GPL  **
** included in the packaging of this file.  Please review the      **
** following information to ensure the GNU General Public License  **
** version 3.0 requirements will be met:                           **
** http://www.gnu.org/copyleft/gpl.html.                           **
**                                                                 **
** The development of this software was supported by the           **
** Excellence Cluster EXC 277 Cognitive Interaction Technology.    **
** The Excellence Cluster EXC 277 is a grant of the Deutsche       **
** Forschungsgemeinschaft (DFG) in the context of the German       **
** Excellence Initiative.                                          **
**                                                                 **
*********************************************************************/

#pragma once

#include <pthread.h>
#include <ICLUtils/Uncopyable.h>

namespace icl{
  namespace utils{
  
    /** \cond */
    class Lockable;
    /** \endcond */  
  
    /// Mutex class of the ICL \ingroup THREAD
    /** This mutex class is a simple object oriented wrapper of the
        pthread_mutex_t struct.
        
        Mutices can be:
        - created (pthread_mutex_init)
        - locked (pthread_mutex_lock)
        - unlocked (pthread_mutex_unlock)
        - and destroyed (Destructor)-> (pthread_mutex_destroy)
    **/
    class Mutex : public Uncopyable{ 
      public:
  
      /// This enum holds available mutex types.
      enum MutexType {
      #ifndef ICL_SYSTEM_WINDOWS
        /// normal mutex can not be locked by owner before unlocking
        mutexTypeNormal = PTHREAD_MUTEX_NORMAL,
        /// recursive mutex can be locked repeatedly by owner-thread. needs equal unlocks.
        mutexTypeRecursive = PTHREAD_MUTEX_RECURSIVE
      #else
  
      #endif
      };
  
      /// Create a mutex
      /**
           @param type The default MutexType is MutexType::mutexTypeNormal
      **/
      Mutex(MutexType type = mutexTypeNormal){
  	  #ifndef ICL_SYSTEM_WINDOWS
        pthread_mutexattr_init(&a);
        pthread_mutexattr_settype(&a, type);
        pthread_mutex_init(&m,&a);
  	  #else
  	  
  	  #endif
      }
      /// Destroys the mutex
      ~Mutex(){
  	  #ifndef ICL_SYSTEM_WINDOWS
          pthread_mutex_destroy(&m);
  	  #else
  	  
  	  #endif
      }
      /// locks the mutex
      void lock(){
  	  #ifndef ICL_SYSTEM_WINDOWS
        pthread_mutex_lock(&m);
  	  #else
  	  
  	  #endif
      }
      /// locks the mutex without blocking. returns immediately.
      /**
          @return zero if lock is acquired. otherwise an error-number
      **/
      int trylock(){
        #ifndef ICL_SYSTEM_WINDOWS
        return pthread_mutex_trylock(&m);
        #else
  
        #endif
      }
  
      /// unlocks the mutex
      void unlock(){
  	  #ifndef ICL_SYSTEM_WINDOWS
        pthread_mutex_unlock(&m);
  	  #else
  	  
  	  #endif
      }
      
      /// Locks a mutex on the stack (mutex is unlocked when the stack's section is released
      class Locker : public Uncopyable{
        public:
        /// Locks the given mutex until the section is leaved
        Locker(Mutex *m);
  
        /// Locks the given mutex until the section is leaved
        Locker(Mutex &m);
  
        /// Locks given lockable unti destruction
        Locker(const Lockable *l);
  
        /// Locks given lockable unti destruction
        Locker(const Lockable &l);
  
        /// unlocks the given mutex (automatically called for objects on the stack)
        ~Locker();
        private:
        /// wrapped mutex
        Mutex *m;
      };
      private:
      /// wrapped thread_mutex_t struct
      pthread_mutex_t m;
      /// wrapped thread_mutexattr struct
      pthread_mutexattr_t a;
    };
    
    
    /** \cond inline implementation of the embedded Locker class */
    inline Mutex::Locker::Locker(Mutex *m):m(m){
      m->lock();
    }
    inline Mutex::Locker::Locker(Mutex &m):m(&m){
      m.lock();
    }
    inline Mutex::Locker::~Locker(){
      m->unlock();
    }
    /** \endcond */
  } // namespace utils
}