/*=========================================================================
  
  Program:   Visualization Toolkit
  Module:    vtkThreadedController.h
  Language:  C++
  Date:      $Date$
  Version:   $Revision$
  
Copyright (c) 1993-2001 Ken Martin, Will Schroeder, Bill Lorensen 
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 * Neither name of Ken Martin, Will Schroeder, or Bill Lorensen nor the names
   of any contributors may be used to endorse or promote products derived
   from this software without specific prior written permission.

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=========================================================================*/
// .NAME vtkThreadedController - Allows communication between running threads.
// .SECTION Description
// vtkThreadedController just uses a vtkMultiThreader to spawn threads.
// It the implements sends and receives using shared memory and reference 
// counting.

// Unfortunately, as this is written, it is not thread safe.  All threads
// use the same controller object, so operations like adding an RMI could
// potentially conflict.  We need to have our own RegisterAndGetGlobalController
// method to create different controllers for each thread.  This would also
// simplify the GetLocalProcessId methods.


// .SECTION see also
// vtkDownStreamPort vtkUpStreamPort vtkMultiThreader vtkMultiProcessController

#ifndef __vtkThreadedController_h
#define __vtkThreadedController_h

#include "vtkObject.h"
#include "vtkMultiProcessController.h"
#include "vtkMultiThreader.h"


class vtkThreadedControllerMessage;


class VTK_EXPORT vtkThreadedController : public vtkMultiProcessController
{
public:
  static vtkThreadedController *New();
  vtkTypeMacro(vtkThreadedController,vtkMultiProcessController);
  void PrintSelf(ostream& os, vtkIndent indent);

  // Description:
  // This method is for setting up the processes.
  void Initialize(int argc, char *arcv[]);

  // Description:
  // This method returns an integer from 0 to (NumberOfProcesses-1)
  // indicating which process we are in.  
  // Note: The correct controller is passed as an argument to
  // the initial function (SingleMethod/MultipleMethod).  Calling this
  // method on another controller may give wrong results.
  vtkGetMacro(LocalProcessId, int);

  // Description:
  // Execute the SingleMethod (as define by SetSingleMethod) using
  // this->NumberOfProcesses processes.  This will only return when
  // all the processes finish executing their methods.
  void SingleMethodExecute();
  
  // Description:
  // Execute the MultipleMethods (as define by calling SetMultipleMethod
  // for each of the required this->NumberOfProcesses methods) using
  // this->NumberOfProcesses processes.
  void MultipleMethodExecute();
    
  //------------------ Communication --------------------
  
  // Description:
  // This method sends data to another process.  Tag eliminates ambiguity
  // and is used to match sends with receives.
  int Send(vtkDataObject *data, int remoteProcessId, int tag);
  int Send(int *data, int length, int remoteProcessId, int tag);
  int Send(unsigned long *data, int length, int remoteProcessId, int tag);
  int Send(char *data, int length, int remoteProcessId, int tag);
  int Send(float *data, int length, int remoteProcessId, int tag);

  // Description:
  // This method receives data from a corresponding send. It blocks
  // until the receive is finished.  
  int Receive(vtkDataObject *data, int remoteProcessId, int tag);
  int Receive(int *data, int length, int remoteProcessId, int tag);
  int Receive(unsigned long *data, int length, int remoteProcessId, int tag);
  int Receive(char *data, int length, int remoteProcessId, int tag);
  int Receive(float *data, int length, int remoteProcessId, int tag);
  
  // Description:
  // First method called after threads are spawned.
  // It is public because the function vtkThreadedControllerStart
  // is not a friend yet.  You should not call this method.
  void Start(int threadIdx);

protected:
  vtkThreadedController();
  ~vtkThreadedController();
  vtkThreadedController(const vtkThreadedController&) {};
  void operator=(const vtkThreadedController&) {};
  
  void CreateProcessControllers();
  vtkThreadedControllerMessage *NewMessage(vtkDataObject *object,
                                           void *data, int dataLength);
  void DeleteMessage(vtkThreadedControllerMessage *message);
  void AddMessage(vtkThreadedControllerMessage *message);
  vtkThreadedControllerMessage *FindMessage(int sendId, int tag);

  // Each Process/Thread has its own controller.
  vtkThreadedController *Controllers[VTK_MP_CONTROLLER_MAX_PROCESSES];

  // Required only for static access to threadId (GetLocalController).
#ifdef VTK_USE_PTHREADS
  pthread_t ThreadIds[VTK_MP_CONTROLLER_MAX_PROCESSES];
#endif
#ifdef VTK_USE_SPROC
  pid_t ThreadIds[VTK_MP_CONTROLLER_MAX_PROCESSES];  
#endif  
  
  // The id for this objects process.
  int LocalProcessId;
  int WaitingForId;

  vtkMultiThreader *MultiThreader;
  // Used internally to switch between multiple and single method execution.
  int MultipleMethodFlag;
  
  // It is not enough to block on the messages, we have to mutex 
  // the whole send interaction.  I was trying to avoid a central 
  // mutex (oh well).
  vtkMutexLock *MessageListLock;

  // This mutex is normally locked.  It is used to block the execution 
  // of the receiving process when the send has not been called yet.
  vtkMutexLock *Gate;

  // Double linked list.
  vtkThreadedControllerMessage *MessageListStart;
  vtkThreadedControllerMessage *MessageListEnd;
  
  // Trying to track down lockups.
  FILE *LogFile;
  

  // The generic send and receive methods.
  int Send(vtkDataObject *object, void *data, int dataLength, 
	   int remoteProcessId, int tag);
  int Receive(vtkDataObject *object, void *data, int dataLength, 
	      int remoteProcessId, int tag);

  // For static GetGlobalController.  Translates controller for thread0
  // to controller for local thread.
  vtkMultiProcessController *GetLocalController();
  
};


#endif


