xgetprop.c

早期freebsd实现

/* $XConsortium: XGetProp.c,v 11.17 91/01/06 11:46:15 rws Exp $ */
/* Copyright    Massachusetts Institute of Technology    1986	*/

/*
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, and that the name of M.I.T. not be used in advertising or
publicity pertaining to distribution of the software without specific,
written prior permission.  M.I.T. makes no representations about the
suitability of this software for any purpose.  It is provided "as is"
without express or implied warranty.
*/

#define NEED_REPLIES
#include "Xlibint.h"

int
XGetWindowProperty(dpy, w, property, offset, length, delete, 
	req_type, actual_type, actual_format, nitems, bytesafter, prop)
    register Display *dpy;
    Window w;
    Atom property;
    Bool delete;
    Atom req_type;
    Atom *actual_type;		/* RETURN */
    int *actual_format;  	/* RETURN  8, 16, or 32 */
    long offset, length;
    unsigned long *nitems; 	/* RETURN  # of 8-, 16-, or 32-bit entities */
    unsigned long *bytesafter;	/* RETURN */
    unsigned char **prop;	/* RETURN */
    {
    xGetPropertyReply reply;
    register xGetPropertyReq *req;
    LockDisplay(dpy);
    GetReq (GetProperty, req);
    req->window = w;
    req->property = property;
    req->type = req_type;
    req->delete = delete;
    req->longOffset = offset;
    req->longLength = length;
    
    if (!_XReply (dpy, (xReply *) &reply, 0, xFalse)) {
	UnlockDisplay(dpy);
	SyncHandle();
	return (1);	/* not Success */
	}	

    *prop = (unsigned char *) NULL;
    if (reply.propertyType != None) {
	long nbytes, netbytes;
	switch (reply.format) {
      /* 
       * One extra byte is malloced than is needed to contain the property
       * data, but this last byte is null terminated and convenient for 
       * returning string properties, so the client doesn't then have to 
       * recopy the string to make it null terminated. 
       */
	  case 8:
	    nbytes = netbytes = reply.nItems;
	    if (*prop = (unsigned char *) Xmalloc ((unsigned)nbytes + 1))
		_XReadPad (dpy, (char *) *prop, netbytes);
	    break;

	  case 16:
	    nbytes = reply.nItems * sizeof (short);
	    netbytes = reply.nItems << 1;
	    if (*prop = (unsigned char *) Xmalloc ((unsigned)nbytes + 1))
		_XRead16Pad (dpy, (short *) *prop, netbytes);
	    break;

	  case 32:
	    nbytes = reply.nItems * sizeof (long);
	    netbytes = reply.nItems << 2;
	    if (*prop = (unsigned char *) Xmalloc ((unsigned)nbytes + 1))
		_XRead32 (dpy, (long *) *prop, netbytes);
	    break;

	  default:
	    /*
	     * This part of the code should never be reached.  If it is,
	     * the server sent back a property with an invalid format.
	     * This is a BadImplementation error. 
	     */
	    {
		xError error;
		error.sequenceNumber = dpy->request;
		error.type = X_Error;
		error.majorCode = X_GetProperty;
		error.minorCode = 0;
		error.errorCode = BadImplementation;
		_XError(dpy, &error);
	    }
	    netbytes = 0L;
	    break;
	}
	if (! *prop) {
	    _XEatData(dpy, (unsigned long) netbytes);
	    UnlockDisplay(dpy);
	    SyncHandle();
	    return(BadAlloc);	/* not Success */
	}
	(*prop)[nbytes] = '\0';
    }
    *actual_type = reply.propertyType;
    *actual_format = reply.format;
    *nitems = reply.nItems;
    *bytesafter = reply.bytesAfter;
    UnlockDisplay(dpy);
    SyncHandle();
    return(Success);
}