xenocara/app/bitmap/ReqMach.c

/*

Copyright 1989, 1998  The Open Group

Permission to use, copy, modify, distribute, and sell this software and its
documentation for any purpose is hereby granted without fee, provided that
the above copyright notice appear in all copies and that both that
copyright notice and this permission notice appear in supporting
documentation.

The above copyright notice and this permission notice shall be included
in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
IN NO EVENT SHALL THE OPEN GROUP BE LIABLE FOR ANY CLAIM, DAMAGES OR
OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
OTHER DEALINGS IN THE SOFTWARE.

Except as contained in this notice, the name of The Open Group shall
not be used in advertising or otherwise to promote the sale, use or
other dealings in this Software without prior written authorization
from The Open Group.

*/

/*
 * Author:  Davor Matic, MIT X Consortium
 */

#include <X11/IntrinsicP.h>
#include <X11/StringDefs.h>
#include <X11/Xfuncs.h>
#include <X11/Xos.h>
#include "BitmapP.h"
    
#include <stdio.h>
#include <math.h>


/*****************************************************************************\
 * Request Machine: stacks up and handles requests from application calls.   * 
\*****************************************************************************/

/*
 * Searches for a request record of a request specified by its name.
 * Returns a pointer to the record or NULL if the request was not found.
 */
static BWRequestRec *
FindRequest(BWRequest name)
{
    int i;

    for (i = 0; i < bitmapClassRec.bitmap_class.num_requests; i++)
	if (!strcmp(name, bitmapClassRec.bitmap_class.requests[i].name))
	    return &bitmapClassRec.bitmap_class.requests[i];
    
    return NULL;
}

/*
 * Adds a request to the request stack and does proper initializations.
 * Returns TRUE if the request was found and FALSE otherwise.
 */
Boolean 
BWAddRequest(Widget w, BWRequest name, Boolean trap, 
	     XtPointer call_data, Cardinal call_data_size)
{
    BitmapWidget BW = (BitmapWidget) w;
    BWRequestRec *request;
    
    request = FindRequest(name);
    if(request) {
	if (DEBUG)
	  fprintf(stderr, "Adding... Cardinal: %d\n", BW->bitmap.cardinal + 1);

	BW->bitmap.request_stack = (BWRequestStack *)
	    XtRealloc((char *)BW->bitmap.request_stack,
		      (++BW->bitmap.cardinal + 1) * sizeof(BWRequestStack));
	
	BW->bitmap.request_stack[BW->bitmap.cardinal].request = request;
	BW->bitmap.request_stack[BW->bitmap.cardinal].status = 
	    XtMalloc(request->status_size);
	BW->bitmap.request_stack[BW->bitmap.cardinal].trap = trap;
	BW->bitmap.request_stack[BW->bitmap.cardinal].call_data = 
	    XtMalloc(call_data_size);
	memmove( BW->bitmap.request_stack[BW->bitmap.cardinal].call_data,
	      call_data, 
	      call_data_size);

	return True;
    }
    else {
	XtWarning("bad request name.  BitmapWidget");
	return False;
    }
}

/*
 * Engages the request designated by the current parameter.
 * Returnes TRUE if the request has an engage function and FALSE otherwise.
 */
static Boolean 
Engage(BitmapWidget BW, Cardinal current)
{
    BW->bitmap.current = current;
    
    if (DEBUG)
	fprintf(stderr, "Request: %s\n", 
		BW->bitmap.request_stack[current].request->name);
  
    if (BW->bitmap.request_stack[current].request->engage) {
	(*BW->bitmap.request_stack[current].request->engage)
	    ((Widget) BW,
	     BW->bitmap.request_stack[current].status,
	     BW->bitmap.request_stack[current].request->engage_client_data,
	     BW->bitmap.request_stack[current].call_data);
	return True;
    }
    else
	return False;
}

/* Boolean BWTerminateRequest();
   Boolean BWRemoveRequest(); */

/*
 * Scans down the request stack removing all requests untill it finds 
 * one to be trapped.
 */
static void 
TrappingLoop(BitmapWidget BW)
{

    if (DEBUG)
	fprintf(stderr, "Scanning... Current: %d\n", BW->bitmap.current);
    if ((BW->bitmap.current > 0) 
	&& 
	(!BW->bitmap.request_stack[BW->bitmap.current--].trap)) {
	BWRemoveRequest((Widget) BW);
	TrappingLoop(BW);
    }
    else
	if (BW->bitmap.cardinal > 0) {
	    if (DEBUG)
		fprintf(stderr, "Trapping... Current: %d\n", BW->bitmap.current+1);
	    if(!Engage(BW, ++BW->bitmap.current))
		BWTerminateRequest((Widget) BW, True);
	}
}
/*
 * Terimantes the current request and continues with next request if con = TRUE
 * Returnes TRUE if there is any number of requests left on the stack.
 */
Boolean 
BWTerminateRequest(Widget w, Boolean cont)
{
    BitmapWidget BW = (BitmapWidget) w;
    
    if (BW->bitmap.current > 0) {
	if (DEBUG)
	    fprintf(stderr, "Terminating... Current: %d\n", BW->bitmap.current);
    	if (BW->bitmap.request_stack[BW->bitmap.current].request->terminate)
	    (*BW->bitmap.request_stack[BW->bitmap.current].request->terminate)
		(w,
		 BW->bitmap.request_stack[BW->bitmap.current].status,
		 BW->bitmap.request_stack[BW->bitmap.current].request->terminate_client_data);
	
	if (cont) {
	    if (BW->bitmap.current == BW->bitmap.cardinal)
		TrappingLoop(BW);
	    else {
		if (DEBUG)
		    fprintf(stderr, "Continuing... Current: %d\n", BW->bitmap.current+1);
		if (!Engage(BW, ++BW->bitmap.current))
		    BWTerminateRequest(w, True);
	    }
	}
	else
	    BW->bitmap.current = 0;
    }
    
    return BW->bitmap.current;
}

/*
 * Simple interface to BWTerminateRequest that takes only a widget.
 */
void 
BWAbort(Widget w)
{
    BWTerminateRequest(w, True);
}

/*
 * Removes the top request from the request stack. If the request is active
 * it will terminate it.
 * Returns TRUE if the number of requests left on the stack != 0.
 */
Boolean 
BWRemoveRequest(Widget w)
{
    BitmapWidget BW = (BitmapWidget) w;
    
    if (BW->bitmap.cardinal > 0) {
	if (DEBUG)
	    fprintf(stderr, "Removing... Cardinal: %d\n", BW->bitmap.cardinal);
	if (BW->bitmap.current == BW->bitmap.cardinal)
	    BWTerminateRequest(w, False);
	
	if (BW->bitmap.request_stack[BW->bitmap.cardinal].request->remove)
	    (*BW->bitmap.request_stack[BW->bitmap.cardinal].request->remove)
		(w,
		 BW->bitmap.request_stack[BW->bitmap.cardinal].status,
		 BW->bitmap.request_stack[BW->bitmap.cardinal].request->remove_client_data);
	
	XtFree(BW->bitmap.request_stack[BW->bitmap.cardinal].status);
	XtFree(BW->bitmap.request_stack[BW->bitmap.cardinal].call_data);
	BW->bitmap.request_stack = (BWRequestStack *)
	    XtRealloc((char *)BW->bitmap.request_stack,
		      (--BW->bitmap.cardinal + 1) * sizeof(BWRequestStack));
	
	return True;
    }
    else 
	return False;
}

void 
BWRemoveAllRequests(Widget w)
{
    while (BWRemoveRequest(w)) {/* removes all requests from the stack */}
}

/*
 * Adds the request to the stack and performs engaging ritual.
 * Returns TRUE if the request was found, FALSE otherwise.
 */
Boolean 
BWEngageRequest(Widget w, BWRequest name, Boolean trap, 
		XtPointer call_data, Cardinal call_data_size)
{
    BitmapWidget BW = (BitmapWidget) w;
    
    if (BWAddRequest(w, name, trap, call_data, call_data_size)) {
	BWTerminateRequest(w, False);
	if (DEBUG)
	    fprintf(stderr, "Engaging... Cardinal: %d\n", BW->bitmap.cardinal);
	if (!Engage(BW, BW->bitmap.cardinal))
	    BWTerminateRequest(w, True);
	
	return True;
    }
    else
	return False;
}

/************************* End of the Request Machine ************************/