/* $XConsortium: utm_send.c /main/5 1995/07/15 20:38:59 drk $ */

/*

 * Motif

 *

 * Copyright (c) 1987-2012, The Open Group. All rights reserved.

 *

 * These libraries and programs are free software; you can

 * redistribute them and/or modify them under the terms of the GNU

 * Lesser General Public License as published by the Free Software

 * Foundation; either version 2 of the License, or (at your option)

 * any later version.

 *

 * These libraries and programs are distributed in the hope that

 * they will be useful, but WITHOUT ANY WARRANTY; without even the

 * implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR

 * PURPOSE. See the GNU Lesser General Public License for more

 * details.

 *

 * You should have received a copy of the GNU Lesser General Public

 * License along with these librararies and programs; if not, write

 * to the Free Software Foundation, Inc., 51 Franklin Street, Fifth

 * Floor, Boston, MA 02110-1301 USA

 * 

 */

/*

 * HISTORY

 */

#include <stdio.h>

#include <Xm/TransferT.h>

#include "utm_send.h"

/*

 * The following keeps track of multiple utm requests and

 * pulls the right data off

 */

typedef struct _DataQueueRec {

  XtPointer data;

  struct _DataQueueRec *next, *prev;

} DataQueueRec;

static DataQueueRec *dataQueue, *dataQueueTail  = NULL;

static void EnqueueUtmData(

XtPointer

);

static XtPointer DequeueUtmData(

void

);

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

 | The following functions are used to handle selection/UTM       |

 | requests made from the REQUESTORS side to the owner of the     |

 | selection.                                                     |

 | To send a request, the only function needed is UTMSendMessage. |

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

/*----------------------------------------------------------------*

 |                         UTMSendMessage                         |

 | Send a message with parameters.                                |

 | Arguments:                                                     |

 |         widget - requestor. MUST have destination callback set |

 |                  to UTMDestinationProc below.

 |         selection - selection to convert against.              |

 |         target - target to make request against.               |

 |         param - data to send to selection owner.               |

 |         param_len - length of param in fmt units.              |

 |         param_fmt - param format (should be WSM_PROTO_FMT).    |

 |         callback - function to invoke when done.               |

 |         closure - data to pass to the callback.                |

 |         time - timestamp of the event; not CurrentTime.        | 

 *----------------------------------------------------------------*/

void

UTMSendMessage(

     Widget w,

     Atom selection,

     Atom target,

     XtPointer param,

     unsigned long paramLen,

     int paramFmt,

     XtCallbackProc doneProc,

     XtPointer closure,

     Time time)

{

  UTMPackageRec *pUtmData;

  /* make sure timestamp is valid

  if (time == 0) time = GetTimestamp(XtDisplay(w)); */

  /* allocates and builds utm package to send. */

  pUtmData = (UTMPackageRec *) XtMalloc(sizeof(UTMPackageRec));

  pUtmData->fmt = paramFmt;

  pUtmData->len = paramLen;

  pUtmData->target = target;

  pUtmData->param = param;

  pUtmData->doneProc = doneProc;

  pUtmData->closure = closure;

  /*

   * queue-up the data which is pulled off in the

   * UTMDestinationProc below. Note that the widget

   * passed in MUST have its destinationCallback set

   * to UTMDestionationProc!

   */

  EnqueueUtmData(pUtmData);

  /*

   * This causes the DestinationCB to be invoked.

   * That is where that param data is transfered.

   */

  if (!XmeNamedSink(w,

		    selection,

		    XmCOPY,

		    NULL, /* location_data. holds param data (client data),

			     free in TransferDone proc. */

		    time))

    fprintf(stderr, "UTM Error: UTMSendMessage failed.\n");

} /* UTMSendMessage */

/*----------------------------------------------------------------*

 |                      UTMDestinationProc                        |

 | Invoked by UTM when a sink has been set-up and a request       |

 | initiated against an owner of a selection.                     |

 | Arguments: w - the requestor widget                            |

 |            clientData - not used. data is in the queue.        |

 |            callData - pointer to the data passed in the call   |

 |                       XmeNamedSink().  This will assume that   |

 |                       the structure pointed to is a UTMDataRec.|

 | Returns: none                                                  |

 |                                                                |

 | Comments:                                                      |

 |    Xt's selection mechanism will not work if the same time-    |

 |    stamp is used. prevTimeStamp contains the time of the last  |

 |    conversion and if same (or greater) it is incremented.      |

 *----------------------------------------------------------------*/

void

UTMDestinationProc (

     Widget w,

     XtPointer clientData,

     XtPointer callData)

{

  static Time prevTimestamp = 0;

  static Time increment = 0;

  Time time;

  XmDestinationCallbackStruct *dcs = (XmDestinationCallbackStruct *)callData;

  UTMPackageRec *pUtmData;

  if (dcs == NULL)

    {

      /* bad data - just return. */

      return;

    }

  /* if duplicate timestamps are used, then make sure they're different. */

  if (prevTimestamp == dcs->time)

    {

      time = prevTimestamp + (++increment);

    }

  else

    {

      increment = 0;

      prevTimestamp = time = dcs->time;

    }

  /* pull off the real client data */

  pUtmData = (UTMPackageRec *)DequeueUtmData();

  /* if no UTMData, then transfer can't be done. Punt. */

  if (pUtmData == NULL)

    return;

  /* Setup the parameters to pass. */

  XmTransferSetParameters(dcs->transfer_id,

			  pUtmData->param, /* ptr to parameter data. */

			  pUtmData->fmt, /* param format (8,16,32) */

			  pUtmData->len, /* size of param in fmt units */

			  dcs->selection); /* not used */

  /* Make the transfer. This invokes the selection owner's ConvertCB.

   * When done, UTMReplyReceived callback proc is invoked.

   */

  XmTransferValue(dcs->transfer_id,

		  pUtmData->target, /* this is the target to convert against.*/

		  pUtmData->doneProc, /* an XtCallbackProc called when done. */

		  pUtmData->closure,  /* client data passed to done proc */

		  time);

  /* don't need the structure any more. */

  XtFree((char*)pUtmData);

} /* UTMDestinationProc */

/*----------------------------------------------------------------*

 |                          EnqueueUtmData                        |

 | Puts data onto the queue between sending messages and having   |

 | the destination callback invoked.                              |

 *----------------------------------------------------------------*/

static void

EnqueueUtmData(XtPointer data)

{

  DataQueueRec *dataRec = (DataQueueRec *)XtMalloc(sizeof(DataQueueRec));

  dataRec->data = data;

  dataRec->next = dataQueue;

  dataRec->prev = NULL;

  if (dataQueue == NULL)

    dataQueueTail = dataRec;

  else

    dataQueue->prev = dataRec;

  dataQueue = dataRec;

  return;

}

/*----------------------------------------------------------------*

 |                          DequeueUtmData                        |

 | Retreives data from the data queue after the destination proc  |

 | was called. Just grab the last entry in the queue.             |

 *----------------------------------------------------------------*/

static XtPointer

DequeueUtmData()

{

  DataQueueRec *ptr = dataQueueTail;

  XtPointer dataPtr = NULL;

  if (ptr)

    {

      dataQueueTail = ptr->prev;

      if (ptr->prev != NULL)

	ptr->prev->next = NULL;

      else

	dataQueue = NULL;

      dataPtr = ptr->data;

      XtFree((char*)ptr);

    }

  else

    fprintf(stderr, "UTM ERROR: Data not found in queue.\n");

  return (dataPtr);

}