/*=========================================================================

  Program:   Visualization Toolkit
  Module:    vtkSharedMemoryCommunicator.cxx

  Copyright (c) Ken Martin, Will Schroeder, Bill Lorensen
  All rights reserved.
  See Copyright.txt or http://www.kitware.com/Copyright.htm for details.

     This software is distributed WITHOUT ANY WARRANTY; without even
     the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
     PURPOSE.  See the above copyright notice for more information.

=========================================================================*/

#include "vtkSharedMemoryCommunicator.h"

#include "vtkCriticalSection.h"
#include "vtkDataArray.h"
#include "vtkDataObject.h"
#include "vtkMultiProcessController.h"
#include "vtkObjectFactory.h"

class vtkSharedMemoryCommunicatorMessage
{
public:
  vtkDataObject *Object;
  vtkDataArray  *Array;
  void          *Data;
  int            DataLength;
  int            Tag;
  int            SendId;
  vtkSharedMemoryCommunicatorMessage* Next;
  vtkSharedMemoryCommunicatorMessage* Previous;
};

vtkCxxRevisionMacro(vtkSharedMemoryCommunicator, "1.18");
vtkStandardNewMacro(vtkSharedMemoryCommunicator);

void vtkSharedMemoryCommunicator::PrintSelf(ostream& os, vtkIndent indent)
{
  this->Superclass::PrintSelf(os,indent);
  os << indent << "Number of threads: " << this->NumberOfThreads << endl;
  os << indent << "Initialized: " << (this->Initialized ? "(yes)" : "(no)")
     << endl;
  os << indent << "Local thread id: " << this->LocalThreadId << endl;
  os << indent << "Waiting for id: " << this->WaitingForId << endl;
  os << indent << "Force deep copy: " << (this->ForceDeepCopy ? "(yes)" : "(no)")
     << endl;
  os << indent << "Message list lock" << this->MessageListLock << endl;
  os << indent << "Communicators: " << this->Communicators << endl;
  os << indent << "Parent: " << this->Parent << endl;
  os << indent << "Message list start: " << this->MessageListStart << endl;
  os << indent << "Message list end: " << this->MessageListEnd << endl;
  
}

vtkSharedMemoryCommunicator::vtkSharedMemoryCommunicator()
{
  this->NumberOfThreads = 0;
  this->Initialized = 0;
  this->Communicators = 0;
  this->Parent = 0;

  this->LocalThreadId = 0;
  this->WaitingForId = vtkMultiProcessController::INVALID_SOURCE;
  this->ForceDeepCopy = 1;

  this->MessageListLock = new vtkSimpleCriticalSection;
  
#ifdef _WIN32
  this->MessageSignal = CreateEvent(0, FALSE, FALSE, 0);
#else
  this->Gate = new vtkSimpleCriticalSection;
  this->Gate->Lock();
#endif

  this->MessageListStart = 0;
  this->MessageListEnd = 0;
}

vtkSharedMemoryCommunicator::~vtkSharedMemoryCommunicator()
{
  delete[] this->Communicators;
  this->Communicators = 0;

  // Note the communicators are not deleted because ThreadedControllers
  // delete them when they are destroyed
  delete this->MessageListLock;
#ifdef _WIN32
  CloseHandle(this->MessageSignal);
#else
  delete this->Gate;
#endif
}

void vtkSharedMemoryCommunicator::Initialize(int nThreads, int forceDeepCopy)
{
  // Can only be initialized once.
  if (this->Initialized)
    {
    return;
    }
  
  // This should never happen. The controller should not call
  // Initialize() if 
  // nThreads >= vtkMultiProcessController::MAX_PROCESSES
  if (nThreads >= vtkMultiProcessController::MAX_PROCESSES)
    {
    return;
    }

  this->NumberOfThreads = nThreads;
  this->Communicators = new vtkSharedMemoryCommunicator*[nThreads];
  this->Communicators[0] = this;
  this->Parent = this;
  this->ForceDeepCopy = forceDeepCopy;

  // Create nThreads communicators. One for each thread.
  for (int i = 1; i < this->NumberOfThreads; ++i)
    {
    this->Communicators[i] = vtkSharedMemoryCommunicator::New();
    this->Communicators[i]->Initialize(1, forceDeepCopy);
    this->Communicators[i]->LocalThreadId = i;
    this->Communicators[i]->Parent = this;
    }

  this->Initialized = 1;
  this->Modified();
}  


int vtkSharedMemoryCommunicator::Send(vtkDataObject* object, 
                                      void *data, int dataLength,
                                      int remoteThreadId, int tag)
{
  vtkSharedMemoryCommunicatorMessage* message;
  vtkSharedMemoryCommunicator* receiveCommunicator;
  receiveCommunicator = this->Parent->Communicators[remoteThreadId];

  // >>>>>>>>>> Lock >>>>>>>>>>
  receiveCommunicator->MessageListLock->Lock();
  // Create and copy the message.
  message = receiveCommunicator->NewMessage(object, data, dataLength);
  message->SendId = this->LocalThreadId;
  message->Tag = tag;
  
  receiveCommunicator->AddMessage(message);

  // Check to see if the other process is blocked waiting for this message.
  if (receiveCommunicator->WaitingForId == this->LocalThreadId ||
      receiveCommunicator->WaitingForId == 
      vtkMultiProcessController::ANY_SOURCE)
    {
    
    // Do this here before the MessageList is unlocked (avoids a race condition).
    receiveCommunicator->WaitingForId = 
      vtkMultiProcessController::INVALID_SOURCE;
    // Tell the receiving thread that there is a new message.
    this->SignalNewMessage(receiveCommunicator);
    }

  receiveCommunicator->MessageListLock->Unlock();
  // <<<<<<<<< Unlock <<<<<<<<<<

  return 1;
}

int vtkSharedMemoryCommunicator::Send(vtkDataArray* object, 
                                      int dataLength,
                                      int remoteThreadId, int tag)
{
  vtkSharedMemoryCommunicatorMessage* message;
  vtkSharedMemoryCommunicator* receiveCommunicator;
  receiveCommunicator = this->Parent->Communicators[remoteThreadId];

  // >>>>>>>>>> Lock >>>>>>>>>>
  receiveCommunicator->MessageListLock->Lock();
  // Create and copy the message.
  message = receiveCommunicator->NewMessage(object, NULL, dataLength);
  message->SendId = this->LocalThreadId;
  message->Tag = tag;
  
  receiveCommunicator->AddMessage(message);

  // Check to see if the other process is blocked waiting for this message.
  if (receiveCommunicator->WaitingForId == this->LocalThreadId ||
      receiveCommunicator->WaitingForId == 
      vtkMultiProcessController::ANY_SOURCE)
    {
    
    // Do this here before the MessageList is unlocked (avoids a race condition).
    receiveCommunicator->WaitingForId = 
      vtkMultiProcessController::INVALID_SOURCE;
    // Tell the receiving thread that there is a new message.
    this->SignalNewMessage(receiveCommunicator);
    }

  receiveCommunicator->MessageListLock->Unlock();
  // <<<<<<<<< Unlock <<<<<<<<<<

  return 1;
}


int vtkSharedMemoryCommunicator::Receive(vtkDataObject* object, 
                                         void *data, int dataLength,
                                         int remoteThreadId, int tag)
{
  vtkSharedMemoryCommunicatorMessage* message;

  // >>>>>>>>>> Lock >>>>>>>>>>
  this->MessageListLock->Lock();
  
  // Look for the message (has it arrived before me?).
  message = this->FindMessage(remoteThreadId, tag);
  while (message == NULL)
    {
    
    this->WaitingForId = remoteThreadId;
    // Temporarily unlock the mutex until we receive the message.
    this->MessageListLock->Unlock();
    // Block until the message arrives.
    this->WaitForNewMessage();
    // Now lock the mutex again.  The message should be here.
    this->MessageListLock->Lock();
    message = this->FindMessage(remoteThreadId, tag);
    if (message == NULL)
      {
      vtkErrorMacro("I passed through the gate, but there is no message.");
      }
    }

  // Copy the message to the receive data/object.
  if (object && message->Object)
    {
    // The object was already copied into the message.
    // We can shallow copy here even if deep copy was set.
    ((vtkDataObject *)object)->ShallowCopy(message->Object);
    }
  if (data != NULL && message->Data != NULL && dataLength > 0)
    {
    if (dataLength != message->DataLength)
      {
      vtkErrorMacro("Receive message length does not match send.");
      }
    memcpy(data, message->Data, dataLength);
    }


  // Delete the message.
  this->DeleteMessage(message);

  this->MessageListLock->Unlock();
  // <<<<<<<<< Unlock <<<<<<<<<

  return 1;
}

int vtkSharedMemoryCommunicator::Receive(vtkDataArray* object, 
                                         int vtkNotUsed(dataLength),
                                         int remoteThreadId, int tag)
{
  vtkSharedMemoryCommunicatorMessage* message;

  // >>>>>>>>>> Lock >>>>>>>>>>
  this->MessageListLock->Lock();
  
  // Look for the message (has it arrived before me?).
  message = this->FindMessage(remoteThreadId, tag);
  while (message == NULL)
    {
    
    this->WaitingForId = remoteThreadId;
    // Temporarily unlock the mutex until we receive the message.
    this->MessageListLock->Unlock();
    // Block until the message arrives.
    this->WaitForNewMessage();
    // Now lock the mutex again.  The message should be here.
    this->MessageListLock->Lock();
    message = this->FindMessage(remoteThreadId, tag);
    if (message == NULL)
      {
      vtkErrorMacro("I passed through the gate, but there is no message.");
      }
    }

  // Copy the message to the receive data/object.
  if (object && message->Array)
    {
    // The array was already copied into the message.
    // We can shallow copy here even if deep copy was set.
    ((vtkDataArray *)object)->DeepCopy(message->Array);
    }


  // Delete the message.
  this->DeleteMessage(message);

  this->MessageListLock->Unlock();
  // <<<<<<<<< Unlock <<<<<<<<<

  return 1;
}

vtkSharedMemoryCommunicatorMessage 
*vtkSharedMemoryCommunicator::NewMessage(vtkDataObject* object, 
                                         void* data, int dataLength)
{
  vtkSharedMemoryCommunicatorMessage *message = 
    new vtkSharedMemoryCommunicatorMessage;

  message->Next = message->Previous = NULL;
  message->Tag = 0;
  message->Object = NULL;
  message->Data = NULL;
  message->DataLength = 0;
  message->Array = 0;

  if (object)
    {
    message->Object = object->NewInstance();
    if (this->ForceDeepCopy)
      {
      message->Object->DeepCopy(object);
      }
    else
      {
      message->Object->ShallowCopy(object);
      }
    }
  if (data && dataLength > 0)
    {
    message->Data = (void *)(new unsigned char[dataLength]);
    message->DataLength = dataLength;
    memcpy(message->Data, data, dataLength);
    }

  return message;
}

vtkSharedMemoryCommunicatorMessage 
*vtkSharedMemoryCommunicator::NewMessage(vtkDataArray* object, 
                                         void* data, int dataLength)
{
  vtkSharedMemoryCommunicatorMessage *message = 
    new vtkSharedMemoryCommunicatorMessage;

  message->Next = message->Previous = NULL;
  message->Tag = 0;
  message->Object = NULL;
  message->Array = NULL;
  message->Data = NULL;
  message->DataLength = 0;

  if (object)
    {
    message->Array = object->NewInstance();
    if (this->ForceDeepCopy)
      {
      message->Array->DeepCopy(object);
      }
    else
      {
      message->Array->DeepCopy(object);
      }
    }
  if (data && dataLength > 0)
    {
    message->Data = (void *)(new unsigned char[dataLength]);
    message->DataLength = dataLength;
    memcpy(message->Data, data, dataLength);
    }

  return message;
}

//----------------------------------------------------------------------------
// This method assumes that the message list mutex is handled externally.
vtkSharedMemoryCommunicatorMessage *vtkSharedMemoryCommunicator::FindMessage(
  int sendId, int tag)
{
  vtkSharedMemoryCommunicatorMessage *message;
  
  message = this->MessageListStart;
  while (message != NULL)
    {
    if ((sendId == vtkMultiProcessController::ANY_SOURCE 
         || message->SendId == sendId) &&
         message->Tag == tag)
      { // We have found a message that matches.
      // Remove the message from the list.

      if (message->Next)
        {
        message->Next->Previous = message->Previous;
        }
      if (message->Previous)
        {
        message->Previous->Next = message->Next;
        }
      // Special Case: first in the list.
      if (message == this->MessageListStart)
        {
        this->MessageListStart = message->Next;
        }
      // Special Case: last in list.
      if (message == this->MessageListEnd)
        {
        this->MessageListEnd = message->Previous;
        }
      
      // Return the message.
      message->Next = message->Previous = NULL;

      return message;
      }
    message = message->Next;
    }
  return NULL;
}

void vtkSharedMemoryCommunicator::DeleteMessage(
  vtkSharedMemoryCommunicatorMessage *message)
{
  if (message->Object)
    {
    message->Object->Delete();
    message->Object = NULL;
    }

  if (message->Array)
    {
    message->Array->Delete();
    message->Array = NULL;
    }

  if (message->Data)
    {
    delete [] (unsigned char*)message->Data;
    message->Data = NULL;
    message->DataLength = 0;
    }

  delete message;
}

void vtkSharedMemoryCommunicator::AddMessage(
  vtkSharedMemoryCommunicatorMessage *message)
{
  // Special case: Empty list.
  if (this->MessageListEnd == NULL)
    {
    // sanity check
    if (this->MessageListStart)
      {
      vtkErrorMacro("List inconsistancy");
      }
    this->MessageListEnd = this->MessageListStart = message;
    message->Next = message->Previous = NULL;
    return;
    }
  
  message->Next = NULL;
  message->Previous = this->MessageListEnd;
  this->MessageListEnd->Next = message;
  this->MessageListEnd = message;
}

//----------------------------------------------------------------------------
int vtkSharedMemoryCommunicator::Send(int* data, int length, 
                                      int remoteThreadId, int tag)
{
  length = length * sizeof(int);
  return this->Send(NULL, (void*)data, length, remoteThreadId, tag);
}

//----------------------------------------------------------------------------
int vtkSharedMemoryCommunicator::Send(unsigned long* data, int length, 
                                      int remoteThreadId, int tag)
{
  length = length * sizeof(unsigned long);
  return this->Send(NULL, (void*)data, length, remoteThreadId, tag);
}

//----------------------------------------------------------------------------
int vtkSharedMemoryCommunicator::Send(char* data, int length, 
                                      int remoteThreadId, int tag)
{
  length = length * sizeof(char);
  return this->Send(NULL, (void*)data, length, remoteThreadId, tag);
}

//----------------------------------------------------------------------------
int vtkSharedMemoryCommunicator::Send(unsigned char* data, int length, 
                                      int remoteThreadId, int tag)
{
  length = length * sizeof(unsigned char);
  return this->Send(NULL, (void*)data, length, remoteThreadId, tag);
}

//----------------------------------------------------------------------------
int vtkSharedMemoryCommunicator::Send(float* data, int length, 
                                      int remoteThreadId, int tag)
{
  length = length * sizeof(float);
  return this->Send(NULL, (void*)data, length, remoteThreadId, tag);
}

//----------------------------------------------------------------------------
int vtkSharedMemoryCommunicator::Send(double* data, int length, 
                                      int remoteThreadId, int tag)
{
  length = length * sizeof(double);
  return this->Send(NULL, (void*)data, length, remoteThreadId, tag);
}

//----------------------------------------------------------------------------
#ifdef VTK_USE_64BIT_IDS
int vtkSharedMemoryCommunicator::Send(vtkIdType* data, int length, 
                                      int remoteThreadId, int tag)
{
  length = length * sizeof(vtkIdType);
  return this->Send(NULL, (void*)data, length, remoteThreadId, tag);
}
#endif

//----------------------------------------------------------------------------
int vtkSharedMemoryCommunicator::Receive(int* data, int length, 
                                         int remoteThreadId, int tag)
{
  length = length * sizeof(int);
  return this->Receive(NULL, (void*)data, length, remoteThreadId, tag);
}

//----------------------------------------------------------------------------
int vtkSharedMemoryCommunicator::Receive(unsigned long* data, 
                                         int length, int remoteThreadId, 
                                         int tag)
{
  length = length * sizeof(unsigned long);
  return this->Receive(NULL, (void*)data, length, remoteThreadId, tag);
}

//----------------------------------------------------------------------------
int vtkSharedMemoryCommunicator::Receive(char* data, int length, 
                                         int remoteThreadId, int tag)
{
  length = length * sizeof(char);
  return this->Receive(NULL, (void*)data, length, remoteThreadId, tag);
}

//----------------------------------------------------------------------------
int vtkSharedMemoryCommunicator::Receive(unsigned char* data, int length, 
                                         int remoteThreadId, int tag)
{
  length = length * sizeof(unsigned char);
  return this->Receive(NULL, (void*)data, length, remoteThreadId, tag);
}

//----------------------------------------------------------------------------
int vtkSharedMemoryCommunicator::Receive(float* data, int length, 
                                         int remoteThreadId, int tag)
{
  length = length * sizeof(float);
  return this->Receive(NULL, (void*)data, length, remoteThreadId, tag);
}

//----------------------------------------------------------------------------
int vtkSharedMemoryCommunicator::Receive(double* data, int length, 
                                         int remoteThreadId, int tag)
{
  length = length * sizeof(double);
  return this->Receive(NULL, (void*)data, length, remoteThreadId, tag);
}

//----------------------------------------------------------------------------
#ifdef VTK_USE_64BIT_IDS
int vtkSharedMemoryCommunicator::Receive(vtkIdType* data, int length, 
                                         int remoteThreadId, int tag)
{
  length = length * sizeof(vtkIdType);
  return this->Receive(NULL, (void*)data, length, remoteThreadId, tag);
}
#endif

//----------------------------------------------------------------------------
int vtkSharedMemoryCommunicator::Send(vtkDataObject* data, 
                                      int remoteThreadId, int tag)
{ 
  return this->Send(data, NULL, 0, remoteThreadId, tag);
}

//----------------------------------------------------------------------------
int vtkSharedMemoryCommunicator::Receive(vtkDataObject* data, 
                                         int remoteThreadId, int tag)
{
  return this->Receive(data, NULL, 0, remoteThreadId, tag);
}

//----------------------------------------------------------------------------
int vtkSharedMemoryCommunicator::Send(vtkDataArray* data, 
                                      int remoteThreadId, int tag)
{ 
  return this->Send(data, 0, remoteThreadId, tag);
}

//----------------------------------------------------------------------------
int vtkSharedMemoryCommunicator::Receive(vtkDataArray* data, 
                                         int remoteThreadId, int tag)
{
  return this->Receive(data, 0, remoteThreadId, tag);
}

//----------------------------------------------------------------------------
void vtkSharedMemoryCommunicator::WaitForNewMessage()
{
#ifdef _WIN32
  WaitForSingleObject( this->MessageSignal, INFINITE );
#else
  this->Gate->Lock();
#endif
}

//----------------------------------------------------------------------------
void vtkSharedMemoryCommunicator::SignalNewMessage(
  vtkSharedMemoryCommunicator* receiveCommunicator)
{
#ifdef _WIN32
  SetEvent( receiveCommunicator->MessageSignal );
#else
  receiveCommunicator->Gate->Unlock();
#endif
}
