/*! \file lib/clipper_thread.h
    Header file for clipper threading handlers
*/
//C Copyright (C) 2000-2006 Kevin Cowtan and University of York
//L
//L  This library is free software and is distributed under the terms
//L  and conditions of version 2.1 of the GNU Lesser General Public
//L  Licence (LGPL) with the following additional clause:
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//L     not covered by this licence.)'
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//L  other terms, please contact the maintainer.
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//L  You can redistribute it and/or modify the library under the terms of
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//L  Lesser General Public License for more details.
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#ifndef CLIPPER_THREAD
#define CLIPPER_THREAD


#include "clipper_message.h"
#include "clipper_sysdep.h"


namespace clipper
{


#ifndef CLIPPER_DISABLE_THREADS


  //! Mutex class: used for locking and unlocking shared resources.
  /*! Create a mutex for any sharted resource, i.e. non-stack object
    used by a multi-threaded program. The lock and unlock methods lock
    that resource. Recursive locks are not allowed. */
  class Mutex {
  public:
    //! constructor: create the mutex
    Mutex()              { CLIPPER_MUTEX_INIT( &mutex ); }
    //! destructor: destroy the mutex
    ~Mutex()             { CLIPPER_MUTEX_FREE( &mutex ); }
    //! lock the mutex
    inline void lock()   { CLIPPER_MUTEX_LOCK( &mutex ); }
    //! unlock the mutex
    inline void unlock() { CLIPPER_MUTEX_UNLK( &mutex ); }
  protected:
    CLIPPER_MUTEX_TYPE mutex;
  };


  //! Thread base class: Override this to create new threads
  /*! To create a thread, override this class. Store data as members
    with accessors to set input and read output. Override the Run()
    method to do the actual work. e.g. the following class implements
    a thread which can sum a list of numbers.
\code
class Thread_test : public Thread_base {
public:
  class Data : public std::vector<int> {
  public:
    Data() {}
    Data( std::vector<int> v ) : std::vector<int>(v) {}
  };

  void Run() {
    sum = 0;
    while ( 1 ) {
        lock();
        int c = current++;
        unlock();
        if ( c >= data_.size() ) break;
        sum += data_[c];
    }
  }
  static void set_data( Data d ) { data_ = d; }
  static Data data_;
  static int current;
  int sum;
};
\endcode
  */

  class Thread_base {
  public:
    Thread_base();
    virtual ~Thread_base() {}
    bool run();
    bool join();
    static void lock()   { mutex_global.lock(); }
    static void unlock() { mutex_global.unlock(); }
    int id() const       { return id_; }

  protected:
    virtual void Run() = 0;

  private:
    static CLIPPER_THREAD_RETTYPE Entry( CLIPPER_THREAD_ARGTYPE thisptr );
    static Mutex mutex_global;
    static int   next_id;
    CLIPPER_THREAD_TYPE thread;
    int id_;
  };


#else


  class Mutex {
  public:
    Mutex()       {}
    ~Mutex()      {}
    inline void lock()   {}
    inline void unlock() {}
  };

  class Thread_base {
  public:
    Thread_base() {}
    virtual ~Thread_base() {}
    bool run()           { Run(); return true; }
    bool join()          { return true; }
    static void lock()   {}
    static void unlock() {}
    int id() const       { return -1; }
  protected:
    virtual void Run() { clipper::Message::message( clipper::Message_fatal( "No Run method defined" ) ); }
  };


#endif


} // namespace clipper

#endif