Threads.h

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//    Copyright 2004, SenseGraphics AB
//
//    This file is part of H3D API.
//
//    H3D API is free software; you can redistribute it and/or modify
//    it under the terms of the GNU General Public License as published by
//    the Free Software Foundation; either version 2 of the License, or
//    (at your option) any later version.
//
//    H3D API is distributed in the hope that it will be useful,
//    but WITHOUT ANY WARRANTY; without even the implied warranty of
//    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
//    GNU General Public License for more details.
//
//    You should have received a copy of the GNU General Public License
//    along with H3D API; if not, write to the Free Software
//    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
//
//    A commercial license is also available. Please contact us at 
//    www.sensegraphics.com for more information.
//
//
//

#ifndef __THREADS_H__
#define __THREADS_H__

#include "H3DApi.h"
#include <list>
#include <vector>
#include <pthread.h>

#ifdef WIN32
#ifdef _MSC_VER
#pragma comment( lib, "pthreadVC2.lib" )
#endif
#define DEFAULT_THREAD_PRIORITY THREAD_PRIORITY_NORMAL
#else
#define DEFAULT_THREAD_PRIORITY 0
#endif

namespace H3D {
  class H3DAPI_API MutexLock {
  public:
    MutexLock();
    
    ~MutexLock();

    void lock();

    void unlock();

    bool tryLock();
        
  protected:
    pthread_mutex_t mutex;
  };


  class H3DAPI_API ConditionLock: public MutexLock {
  public:
    ConditionLock();
    
    ~ConditionLock();

    void wait();

    bool timedWait( unsigned int ms );

    void signal();

    void broadcast();
        
  protected:
    pthread_cond_t cond; 
  };

 
  class H3DAPI_API ThreadBase {
  public:
    virtual ~ThreadBase() {}

    typedef pthread_t ThreadId;

    static ThreadId getCurrentThreadId();

    static ThreadId getMainThreadId() {
      return main_thread_id;
    }
    
    static bool inMainThread();

    inline ThreadId getThreadId() { return thread_id; }
  protected:
    ThreadId thread_id;
    
    static ThreadId main_thread_id;
  };

  class H3DAPI_API PeriodicThreadBase: public ThreadBase {
  public:
    typedef enum {
      CALLBACK_DONE,
      CALLBACK_CONTINUE
    } CallbackCode;

    typedef CallbackCode (*CallbackFunc)(void *data); 

    virtual void synchronousCallback( CallbackFunc func, void *data ) = 0;

    virtual void asynchronousCallback( CallbackFunc func, void *data ) = 0;
  };

  class H3DAPI_API HapticThreadBase {
  public:
    HapticThreadBase();
    
    virtual ~HapticThreadBase();

    static void synchronousHapticCB( PeriodicThreadBase::CallbackFunc func, 
                                     void *data );

    static bool inHapticThread();
  protected:
    // Callback function for synchronising all haptic threads.
    static PeriodicThreadBase::CallbackCode sync_haptics( void * );

    // The haptic threads that have been created.
    static std::vector< HapticThreadBase * > threads;

    // Lock used to get the haptic threads to wait for the callback 
    // function to finish.
    static ConditionLock haptic_lock; 

    // Lock used to get the thread calling the synchronousHapticCB
    // function to wait for all the haptic threads to synchronize.
    static ConditionLock sg_lock; 

    // Counter used when synchronizing haptic threads. It tells how
    // many more haptic threads that are left to synchronize.
    static int haptic_threads_left;
  };

  class H3DAPI_API SimpleThread : public ThreadBase {
  public:
    SimpleThread( void *(func) (void *),
                  void *args = NULL,
                  int thread_priority = DEFAULT_THREAD_PRIORITY );
    
    virtual ~SimpleThread();
  }; 

  class H3DAPI_API PeriodicThread : public PeriodicThreadBase {
  public:
    PeriodicThread( int thread_priority = DEFAULT_THREAD_PRIORITY,
            int thread_frequency = -1 );
    
    virtual ~PeriodicThread();
    
    virtual void synchronousCallback( CallbackFunc func, void *data );

    virtual void asynchronousCallback( CallbackFunc func, void *data );
  protected:
    // The function that handles callbacks. Is also the main function that
    // is run in the thread.
    static void *thread_func( void * );

    typedef std::list< std::pair< CallbackFunc, void * > > CallbackList;
    // A list of the callback functions to run.
    CallbackList callbacks;
    // A lock for synchronizing changes to the callbacks member.
    ConditionLock callback_lock;
    
    int priority;

    int frequency;

  };

  class H3DAPI_API HapticThread : public HapticThreadBase,
                                  public PeriodicThread {
  public:
    HapticThread( int thread_priority =  DEFAULT_THREAD_PRIORITY,
                int thread_frequency = -1 ):
      PeriodicThread( thread_priority, thread_frequency ) {
    }
  };

  class H3DAPI_API HLThread : public HapticThreadBase,
                              public PeriodicThreadBase {

  private:
    HLThread():
      is_active( false ) {
      // the hl thread should not be added unless the hd scheduler
      // has started.
      sg_lock.lock();
      threads.pop_back();
      sg_lock.unlock();
    }
  public:
    static HLThread *getInstance() {
      return singleton;
    }

    inline bool isActive() { return is_active; }

    void setActive( bool _active );

    virtual void synchronousCallback( CallbackFunc func, void *data );

    virtual void asynchronousCallback( CallbackFunc func, void *data );
  protected:
    static PeriodicThread::CallbackCode setThreadId( void * _data );
    static HLThread *singleton;
    bool is_active;
  };

}

#endif

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