lib/Xm-2.1/xdnd.c

/*
 * LessTif ID : $Id: xdnd.c,v 1.1 2004/08/28 19:22:46 dannybackx Exp $
 *
 * This file is maintained by Paul Sheer.
 * Integration with LessTif should be outside this source, so Paul can
 * maintain this file and guarantee that other users (GTK+, ...) use
 * the same version.
 *
 * If the integration is not possible without changing this file,
 * please contact Paul.
 */
/* xdnd.c, xdnd.h - C program library for handling the Xdnd protocol
   Copyright (C) 1998  Paul Sheer

   This library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Library General Public
   License as published by the Free Software Foundation; either
   version 2 of the License, or (at your option) any later version.

   This library is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   Library General Public License for more details.

   You should have received a copy of the GNU Library General Public
   License along with this library; if not, write to the Free
   Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.

   Further info can also be obtained by emailing the author at,
       psheer@obsidian.co.za
 */


/*
   Released 1998-08-07
   Changes:


*/

/*
    TODO:
     - action_choose_dialog not yet supported (never called)
     - widget_delete_selection not yet supported and DELETE requests are ignored
     - not yet tested with applications that only supported XDND 0 or 1
     - INCR protocol not yet implemented
*/

#include <LTconfig.h>

#include <string.h>
#include <stdlib.h>
#include <stdio.h>

#include <X11/Xlib.h>
#include <X11/X.h>
#include <X11/Xatom.h>
#include <Xm/XmP.h>
#include <XmI/xdnd.h>

#include <XmI/DebugUtil.h>

/* #include "mad.h" */

/* just to remind us : */

#if 0
typedef struct {
    int type;
    unsigned long serial;
    Bool send_event;
    Display *display;
    Window window;
    Atom message_type;
    int format;
    union {
	char b[20];
	short s[10];
	long l[5];
    } data;
} XClientMessageEvent;
XClientMessageEvent xclient;
#endif

#define xdnd_xfree(x) {if (x) { free (x); x = 0; }}

#define dnd_version_at_least(a,b) ((a) <= (b))


static unsigned char dnd_copy_cursor_bits[] =
{
  0x00, 0x00, 0x00, 0x00, 0xfe, 0xff, 0x0f, 0x00, 0x02, 0x00, 0x08, 0x01,
  0x02, 0x00, 0x08, 0x01, 0x02, 0x00, 0x08, 0x01, 0x02, 0x00, 0xe8, 0x0f,
  0x02, 0x00, 0x08, 0x01, 0x02, 0x00, 0x08, 0x01, 0x02, 0x00, 0x08, 0x01,
  0x02, 0x00, 0x08, 0x00, 0x02, 0x04, 0x08, 0x00, 0x02, 0x0c, 0x08, 0x00,
  0x02, 0x1c, 0x08, 0x00, 0x02, 0x3c, 0x08, 0x00, 0x02, 0x7c, 0x08, 0x00,
  0x02, 0xfc, 0x08, 0x00, 0x02, 0xfc, 0x09, 0x00, 0x02, 0xfc, 0x0b, 0x00,
  0x02, 0x7c, 0x08, 0x00, 0xfe, 0x6d, 0x0f, 0x00, 0x00, 0xc4, 0x00, 0x00,
  0x00, 0xc0, 0x00, 0x00, 0x00, 0x80, 0x01, 0x00, 0x00, 0x80, 0x01, 0x00,
    0x00, 0x00, 0x00, 0x00};

static unsigned char dnd_copy_mask_bits[] =
{
  0xff, 0xff, 0x1f, 0x00, 0xff, 0xff, 0xff, 0x1f, 0xff, 0xff, 0xff, 0x1f,
  0x07, 0x00, 0xfc, 0x1f, 0x07, 0x00, 0xfc, 0x1f, 0x07, 0x00, 0xfc, 0x1f,
  0x07, 0x00, 0xfc, 0x1f, 0x07, 0x00, 0xfc, 0x1f, 0x07, 0x00, 0xfc, 0x1f,
  0x07, 0x06, 0xfc, 0x1f, 0x07, 0x0e, 0xfc, 0x1f, 0x07, 0x1e, 0x1c, 0x00,
  0x07, 0x3e, 0x1c, 0x00, 0x07, 0x7e, 0x1c, 0x00, 0x07, 0xfe, 0x1c, 0x00,
  0x07, 0xfe, 0x1d, 0x00, 0x07, 0xfe, 0x1f, 0x00, 0x07, 0xfe, 0x1f, 0x00,
  0xff, 0xff, 0x1f, 0x00, 0xff, 0xff, 0x1e, 0x00, 0xff, 0xef, 0x1f, 0x00,
  0x00, 0xe6, 0x01, 0x00, 0x00, 0xc0, 0x03, 0x00, 0x00, 0xc0, 0x03, 0x00,
    0x00, 0x80, 0x01, 0x00};

static unsigned char dnd_move_cursor_bits[] =
{
  0x00, 0x00, 0x00, 0xfe, 0xff, 0x0f, 0x02, 0x00, 0x08, 0x02, 0x00, 0x08,
  0x02, 0x00, 0x08, 0x02, 0x00, 0x08, 0x02, 0x00, 0x08, 0x02, 0x00, 0x08,
  0x02, 0x00, 0x08, 0x02, 0x00, 0x08, 0x02, 0x04, 0x08, 0x02, 0x0c, 0x08,
  0x02, 0x1c, 0x08, 0x02, 0x3c, 0x08, 0x02, 0x7c, 0x08, 0x02, 0xfc, 0x08,
  0x02, 0xfc, 0x09, 0x02, 0xfc, 0x0b, 0x02, 0x7c, 0x08, 0xfe, 0x6d, 0x0f,
  0x00, 0xc4, 0x00, 0x00, 0xc0, 0x00, 0x00, 0x80, 0x01, 0x00, 0x80, 0x01,
    0x00, 0x00, 0x00};

static unsigned char dnd_move_mask_bits[] =
{
  0xff, 0xff, 0x1f, 0xff, 0xff, 0x1f, 0xff, 0xff, 0x1f, 0x07, 0x00, 0x1c,
  0x07, 0x00, 0x1c, 0x07, 0x00, 0x1c, 0x07, 0x00, 0x1c, 0x07, 0x00, 0x1c,
  0x07, 0x00, 0x1c, 0x07, 0x06, 0x1c, 0x07, 0x0e, 0x1c, 0x07, 0x1e, 0x1c,
  0x07, 0x3e, 0x1c, 0x07, 0x7e, 0x1c, 0x07, 0xfe, 0x1c, 0x07, 0xfe, 0x1d,
  0x07, 0xfe, 0x1f, 0x07, 0xfe, 0x1f, 0xff, 0xff, 0x1f, 0xff, 0xff, 0x1e,
  0xff, 0xef, 0x1f, 0x00, 0xe6, 0x01, 0x00, 0xc0, 0x03, 0x00, 0xc0, 0x03,
    0x00, 0x80, 0x01};

static unsigned char dnd_link_cursor_bits[] =
{
  0x00, 0x00, 0x00, 0x00, 0xfe, 0xff, 0x0f, 0x00, 0x02, 0x00, 0x08, 0x01,
  0x02, 0x00, 0x88, 0x00, 0x02, 0x00, 0x48, 0x00, 0x02, 0x00, 0xe8, 0x0f,
  0x02, 0x00, 0x48, 0x00, 0x02, 0x00, 0x88, 0x00, 0x02, 0x00, 0x08, 0x01,
  0x02, 0x00, 0x08, 0x00, 0x02, 0x04, 0x08, 0x00, 0x02, 0x0c, 0x08, 0x00,
  0x02, 0x1c, 0x08, 0x00, 0x02, 0x3c, 0x08, 0x00, 0x02, 0x7c, 0x08, 0x00,
  0x02, 0xfc, 0x08, 0x00, 0x02, 0xfc, 0x09, 0x00, 0x02, 0xfc, 0x0b, 0x00,
  0x02, 0x7c, 0x08, 0x00, 0xfe, 0x6d, 0x0f, 0x00, 0x00, 0xc4, 0x00, 0x00,
  0x00, 0xc0, 0x00, 0x00, 0x00, 0x80, 0x01, 0x00, 0x00, 0x80, 0x01, 0x00,
    0x00, 0x00, 0x00, 0x00};

static unsigned char dnd_link_mask_bits[] =
{
  0xff, 0xff, 0x1f, 0x00, 0xff, 0xff, 0xff, 0x1f, 0xff, 0xff, 0xff, 0x1f,
  0x07, 0x00, 0xfc, 0x1f, 0x07, 0x00, 0xfc, 0x1f, 0x07, 0x00, 0xfc, 0x1f,
  0x07, 0x00, 0xfc, 0x1f, 0x07, 0x00, 0xfc, 0x1f, 0x07, 0x00, 0xfc, 0x1f,
  0x07, 0x06, 0xfc, 0x1f, 0x07, 0x0e, 0xfc, 0x1f, 0x07, 0x1e, 0x1c, 0x00,
  0x07, 0x3e, 0x1c, 0x00, 0x07, 0x7e, 0x1c, 0x00, 0x07, 0xfe, 0x1c, 0x00,
  0x07, 0xfe, 0x1d, 0x00, 0x07, 0xfe, 0x1f, 0x00, 0x07, 0xfe, 0x1f, 0x00,
  0xff, 0xff, 0x1f, 0x00, 0xff, 0xff, 0x1e, 0x00, 0xff, 0xef, 0x1f, 0x00,
  0x00, 0xe6, 0x01, 0x00, 0x00, 0xc0, 0x03, 0x00, 0x00, 0xc0, 0x03, 0x00,
    0x00, 0x80, 0x01, 0x00};

static unsigned char dnd_ask_cursor_bits[] =
{
  0x00, 0x00, 0x00, 0x00, 0xfe, 0xff, 0x0f, 0x00, 0x02, 0x00, 0x88, 0x03,
  0x02, 0x00, 0x48, 0x04, 0x02, 0x00, 0x08, 0x04, 0x02, 0x00, 0x08, 0x02,
  0x02, 0x00, 0x08, 0x01, 0x02, 0x00, 0x08, 0x01, 0x02, 0x00, 0x08, 0x00,
  0x02, 0x00, 0x08, 0x01, 0x02, 0x04, 0x08, 0x00, 0x02, 0x0c, 0x08, 0x00,
  0x02, 0x1c, 0x08, 0x00, 0x02, 0x3c, 0x08, 0x00, 0x02, 0x7c, 0x08, 0x00,
  0x02, 0xfc, 0x08, 0x00, 0x02, 0xfc, 0x09, 0x00, 0x02, 0xfc, 0x0b, 0x00,
  0x02, 0x7c, 0x08, 0x00, 0xfe, 0x6d, 0x0f, 0x00, 0x00, 0xc4, 0x00, 0x00,
  0x00, 0xc0, 0x00, 0x00, 0x00, 0x80, 0x01, 0x00, 0x00, 0x80, 0x01, 0x00,
    0x00, 0x00, 0x00, 0x00};

static unsigned char dnd_ask_mask_bits[] =
{
  0xff, 0xff, 0x1f, 0x00, 0xff, 0xff, 0xff, 0x1f, 0xff, 0xff, 0xff, 0x1f,
  0x07, 0x00, 0xfc, 0x1f, 0x07, 0x00, 0xfc, 0x1f, 0x07, 0x00, 0xfc, 0x1f,
  0x07, 0x00, 0xfc, 0x1f, 0x07, 0x00, 0xfc, 0x1f, 0x07, 0x00, 0xfc, 0x1f,
  0x07, 0x06, 0xfc, 0x1f, 0x07, 0x0e, 0xfc, 0x1f, 0x07, 0x1e, 0x1c, 0x00,
  0x07, 0x3e, 0x1c, 0x00, 0x07, 0x7e, 0x1c, 0x00, 0x07, 0xfe, 0x1c, 0x00,
  0x07, 0xfe, 0x1d, 0x00, 0x07, 0xfe, 0x1f, 0x00, 0x07, 0xfe, 0x1f, 0x00,
  0xff, 0xff, 0x1f, 0x00, 0xff, 0xff, 0x1e, 0x00, 0xff, 0xef, 0x1f, 0x00,
  0x00, 0xe6, 0x01, 0x00, 0x00, 0xc0, 0x03, 0x00, 0x00, 0xc0, 0x03, 0x00,
    0x00, 0x80, 0x01, 0x00};

static DndCursor dnd_cursors[] =
{
    {29, 25, 10, 10, dnd_copy_cursor_bits, dnd_copy_mask_bits, "XdndActionCopy", 0, 0, 0, 0},
    {21, 25, 10, 10, dnd_move_cursor_bits, dnd_move_mask_bits, "XdndActionMove", 0, 0, 0, 0},
    {29, 25, 10, 10, dnd_link_cursor_bits, dnd_link_mask_bits, "XdndActionLink", 0, 0, 0, 0},
    {29, 25, 10, 10, dnd_ask_cursor_bits, dnd_ask_mask_bits, "XdndActionAsk", 0, 0, 0, 0},
    {0, 0, 0, 0, 0, 0, 0, 0, 0, 0}
};

void xdnd_reset (DndClass * dnd)
{
    dnd->stage = XDND_DROP_STAGE_IDLE;
    dnd->dragging_version = 0;
    dnd->internal_drag = 0;
    dnd->want_position = 0;
    dnd->ready_to_drop = 0;
    dnd->will_accept = 0;
    dnd->rectangle.x = dnd->rectangle.y = 0;
    dnd->rectangle.width = dnd->rectangle.height = 0;
    dnd->dropper_window = 0;
    dnd->dragger_window = 0;
    dnd->dragger_typelist = 0;
    dnd->desired_type = 0;
    dnd->time = 0;
}

void xdnd_init (DndClass * dnd, Display * display)
{
    DndCursor *cursor;
    XColor black, white;
    memset (dnd, 0, sizeof (*dnd));

    dnd->display = display;
    dnd->root_window = DefaultRootWindow (display);
    dnd->version = XDND_VERSION;

    dnd->XdndAware = XInternAtom (dnd->display, "XdndAware", False);
    dnd->XdndSelection = XInternAtom (dnd->display, "XdndSelection", False);
    dnd->XdndEnter = XInternAtom (dnd->display, "XdndEnter", False);
    dnd->XdndLeave = XInternAtom (dnd->display, "XdndLeave", False);
    dnd->XdndPosition = XInternAtom (dnd->display, "XdndPosition", False);
    dnd->XdndDrop = XInternAtom (dnd->display, "XdndDrop", False);
    dnd->XdndFinished = XInternAtom (dnd->display, "XdndFinished", False);
    dnd->XdndStatus = XInternAtom (dnd->display, "XdndStatus", False);
    dnd->XdndActionCopy = XInternAtom (dnd->display, "XdndActionCopy", False);
    dnd->XdndActionMove = XInternAtom (dnd->display, "XdndActionMove", False);
    dnd->XdndActionLink = XInternAtom (dnd->display, "XdndActionLink", False);
    dnd->XdndActionAsk = XInternAtom (dnd->display, "XdndActionAsk", False);
    dnd->XdndActionPrivate = XInternAtom (dnd->display, "XdndActionPrivate", False);
    dnd->XdndTypeList = XInternAtom (dnd->display, "XdndTypeList", False);
    dnd->XdndActionList = XInternAtom (dnd->display, "XdndActionList", False);
    dnd->XdndActionDescription = XInternAtom (dnd->display, "XdndActionDescription", False);

    dnd->Xdnd_NON_PROTOCOL_ATOM = XInternAtom (dnd->display, "JXSelectionWindowProperty", False);

    xdnd_reset (dnd);

    dnd->cursors = dnd_cursors;

    black.pixel = BlackPixel (dnd->display, DefaultScreen (dnd->display));
    white.pixel = WhitePixel (dnd->display, DefaultScreen (dnd->display));

    XQueryColor (dnd->display, DefaultColormap (dnd->display, DefaultScreen (dnd->display)), &black);
    XQueryColor (dnd->display, DefaultColormap (dnd->display, DefaultScreen (dnd->display)), &white);

    for (cursor = &dnd->cursors[0]; cursor->width; cursor++) {
	cursor->image_pixmap = XCreateBitmapFromData \
	    (dnd->display, dnd->root_window, (char *) cursor->image_data, cursor->width, cursor->height);
	cursor->mask_pixmap = XCreateBitmapFromData \
	    (dnd->display, dnd->root_window, (char *) cursor->mask_data, cursor->width, cursor->height);
	cursor->cursor = XCreatePixmapCursor (dnd->display, cursor->image_pixmap,
	      cursor->mask_pixmap, &black, &white, cursor->x, cursor->y);
	XFreePixmap (dnd->display, cursor->image_pixmap);
	XFreePixmap (dnd->display, cursor->mask_pixmap);
	cursor->action = XInternAtom (dnd->display, cursor->_action, False);
    }
}

void xdnd_shut (DndClass * dnd)
{
    DndCursor *cursor;
    for (cursor = &dnd->cursors[0]; cursor->width; cursor++)
	XFreeCursor (dnd->display, cursor->cursor);
    memset (dnd, 0, sizeof (*dnd));
    return;
}


/* typelist is a null terminated array */
static int array_length (Atom * a)
{
    int n;
    for (n = 0; a[n]; n++);
    return n;
}

void xdnd_set_dnd_aware (DndClass * dnd, Window window, Atom * typelist)
{
    XChangeProperty (dnd->display, window, dnd->XdndAware, XA_ATOM, 32, PropModeReplace, (unsigned char *) &dnd->version, 1);
    if (typelist) {
	int n;
	n = array_length (typelist);
	if (n)
	    XChangeProperty (dnd->display, window, dnd->XdndAware, XA_ATOM, 32, PropModeAppend, (unsigned char *) typelist, n);
    }
}

int xdnd_is_dnd_aware (DndClass * dnd, Window window, int *version, Atom * typelist)
{
    Atom actual;
    int format;
    unsigned long count, remaining;
    unsigned char *data = 0;
    Atom *types, *t;
    int result = 1;

    *version = 0;
    XGetWindowProperty (dnd->display, window, dnd->XdndAware,
			0, 0x8000000L, False, XA_ATOM,
			&actual, &format,
			&count, &remaining, &data);

    if (actual != XA_ATOM || format != 32 || count == 0 || !data) {
        DEBUGOUT(_LtDebug(__FILE__, NULL, "XGetWindowProperty failed in xdnd_is_dnd_aware - XdndAware = %ld", dnd->XdndAware));

	if (data)
	    XFree (data);
	return 0;
    }
    types = (Atom *) data;
    *version = dnd->version < types[0] ? dnd->version : types[0];	/* minimum */
    DEBUGOUT(_LtDebug(__FILE__, NULL,"Using XDND version %d", *version));
    if (count > 1) {
	result = 0;
	for (t = typelist; *t; t++) {
	    int j;
	    for (j = 1; j < count; j++) {
		if (types[j] == *t) {
		    result = 1;
		    break;
		}
	    }
	    if (result)
		break;
	}
    }
    XFree (data);
    return result;
}

void xdnd_set_type_list (DndClass * dnd, Window window, Atom * typelist)
{
    int n;
    n = array_length (typelist);
    XChangeProperty (dnd->display, window, dnd->XdndTypeList, XA_ATOM, 32,
		     PropModeReplace, (unsigned char *) typelist, n);
}

/* result must be free'd */
void xdnd_get_type_list (DndClass * dnd, Window window, Atom ** typelist)
{
    Atom type, *a;
    int format, i;
    unsigned long count, remaining;
    unsigned char *data = NULL;

    *typelist = 0;

    XGetWindowProperty (dnd->display, window, dnd->XdndTypeList,
			0, 0x8000000L, False, XA_ATOM,
			&type, &format, &count, &remaining, &data);

    if (type != XA_ATOM || format != 32 || count == 0 || !data) {
	if (data)
	    XFree (data);
        DEBUGOUT(_LtDebug(__FILE__, NULL, "XGetWindowProperty failed in xdnd_get_type_list - dnd->XdndTypeList = %ld", dnd->XdndTypeList));
	return;
    }
    *typelist = malloc ((count + 1) * sizeof (Atom));
    a = (Atom *) data;
    for (i = 0; i < count; i++)
	(*typelist)[i] = a[i];
    (*typelist)[count] = 0;

    XFree (data);
}

void xdnd_get_three_types (DndClass * dnd, XEvent * xevent, Atom ** typelist)
{
    int i;
    *typelist = malloc ((XDND_THREE + 1) * sizeof (Atom));
    for (i = 0; i < XDND_THREE; i++)
	(*typelist)[i] = XDND_ENTER_TYPE (xevent, i);
    (*typelist)[XDND_THREE] = 0;	/* although (*typelist)[1] or (*typelist)[2] may also be set to nill */
}

/* result must be free'd */
static char *concat_string_list (char **t, int *bytes)
{
    int l, n;
    char *s;
    for (l = n = 0;; n++) {
	if (!t[n])
	    break;
	if (!t[n][0])
	    break;
	l += strlen (t[n]) + 1;
    }
    s = malloc (l + 1);
    for (l = n = 0;; n++) {
	if (!t[n])
	    break;
	if (!(t[n][0]))
	    break;
	strcpy (s + l, t[n]);
	l += strlen (t[n]) + 1;
    }
    *bytes = l;
    s[l] = '\0';
    return s;
}

void xdnd_set_actions (DndClass * dnd, Window window, Atom * actions, char **descriptions)
{
    int n, l;
    char *s;
    n = array_length (actions);

    XChangeProperty (dnd->display, window, dnd->XdndActionList, XA_ATOM, 32,
		     PropModeReplace, (unsigned char *) actions, n);

    s = concat_string_list (descriptions, &l);
    XChangeProperty (dnd->display, window, dnd->XdndActionList, XA_STRING, 8,
		     PropModeReplace, (unsigned char *) s, l);
    xdnd_xfree (s);
}

/* returns 1 on error or no actions, otherwise result must be free'd
   xdnd_get_actions (window, &actions, &descriptions);
   free (actions); free (descriptions); */
int xdnd_get_actions (DndClass * dnd, Window window, Atom ** actions, char ***descriptions)
{
    Atom type, *a;
    int format, i;
    unsigned long count, dcount, remaining;
    unsigned char *data = 0, *r;

    *actions = 0;
    *descriptions = 0;
    XGetWindowProperty (dnd->display, window, dnd->XdndActionList,
			0, 0x8000000L, False, XA_ATOM,
			&type, &format, &count, &remaining, &data);

    if (type != XA_ATOM || format != 32 || count == 0 || !data) {
	if (data)
	    XFree (data);
	return 1;
    }
    *actions = malloc ((count + 1) * sizeof (Atom));
    a = (Atom *) data;
    for (i = 0; i < count; i++)
	(*actions)[i] = a[i];
    (*actions)[count] = 0;

    XFree (data);

    data = 0;
    XGetWindowProperty (dnd->display, window, dnd->XdndActionDescription,
			0, 0x8000000L, False, XA_STRING, &type, &format,
			&dcount, &remaining, &data);

    if (type != XA_STRING || format != 8 || dcount == 0) {
	if (data)
	    XFree (data);
	*descriptions = malloc ((count + 1) * sizeof (char *));
	_XmWarning(NULL, "XGetWindowProperty no property or wrong format for action descriptions");
	for (i = 0; i < count; i++)
	    (*descriptions)[i] = "";
	(*descriptions)[count] = 0;
    } else {
	int l;
	l = (count + 1) * sizeof (char *);
	*descriptions = malloc (l + dcount);
	memcpy (*descriptions + l, data, dcount);
	XFree (data);
	data = (unsigned char *) *descriptions;
	data += l;
	l = 0;
	for (i = 0, r = data;; r += l + 1, i++) {
	    l = strlen ((char *) r);
	    if (!l || i >= count)
		break;
	    (*descriptions)[i] = (char *) r;
	}
	for (; i < count; i++) {
	    (*descriptions)[i] = "";
	}
	(*descriptions)[count] = 0;
    }
    return 0;
}

/* returns non-zero on cancel */
int xdnd_choose_action_dialog (DndClass * dnd, Atom * actions, char **descriptions, Atom * result)
{
    if (!actions[0])
	return 1;
    if (!dnd->action_choose_dialog) {	/* default to return the first action if no dialog set */
	*result = actions[0];
	return 0;
    }
    return (*dnd->action_choose_dialog) (dnd, descriptions, actions, result);
}

static void xdnd_send_event (DndClass * dnd, Window window, XEvent * xevent)
{
    XSendEvent (dnd->display, window, 0, 0, xevent);
}

void xdnd_send_enter (DndClass * dnd, Window window, Window from, Atom * typelist)
{
    XEvent xevent;
    int n, i;
    n = array_length (typelist);

    memset (&xevent, 0, sizeof (xevent));

    xevent.xany.type = ClientMessage;
    xevent.xany.display = dnd->display;
    xevent.xclient.window = window;
    xevent.xclient.message_type = dnd->XdndEnter;
    xevent.xclient.format = 32;

    XDND_ENTER_SOURCE_WIN (&xevent) = from;
    XDND_ENTER_THREE_TYPES_SET (&xevent, n > XDND_THREE);
    XDND_ENTER_VERSION_SET (&xevent, dnd->version);
    for (i = 0; i < n && i < XDND_THREE; i++)
	XDND_ENTER_TYPE (&xevent, i) = typelist[i];
    xdnd_send_event (dnd, window, &xevent);
}

void xdnd_send_position (DndClass * dnd, Window window, Window from, Atom action, int x, int y, unsigned long time)
{
    XEvent xevent;

    memset (&xevent, 0, sizeof (xevent));

    xevent.xany.type = ClientMessage;
    xevent.xany.display = dnd->display;
    xevent.xclient.window = window;
    xevent.xclient.message_type = dnd->XdndPosition;
    xevent.xclient.format = 32;

    XDND_POSITION_SOURCE_WIN (&xevent) = from;
    XDND_POSITION_ROOT_SET (&xevent, x, y);
    if (dnd_version_at_least (dnd->dragging_version, 1))
	XDND_POSITION_TIME (&xevent) = time;
    if (dnd_version_at_least (dnd->dragging_version, 2))
	XDND_POSITION_ACTION (&xevent) = action;

    xdnd_send_event (dnd, window, &xevent);
}

void xdnd_send_status (DndClass * dnd, Window window, Window from, int will_accept, \
	      int want_position, int x, int y, int w, int h, Atom action)
{
    XEvent xevent;

    memset (&xevent, 0, sizeof (xevent));

    xevent.xany.type = ClientMessage;
    xevent.xany.display = dnd->display;
    xevent.xclient.window = window;
    xevent.xclient.message_type = dnd->XdndStatus;
    xevent.xclient.format = 32;

    XDND_STATUS_TARGET_WIN (&xevent) = from;
    XDND_STATUS_WILL_ACCEPT_SET (&xevent, will_accept);
    if (will_accept)
	XDND_STATUS_WANT_POSITION_SET (&xevent, want_position);
    if (want_position)
	XDND_STATUS_RECT_SET (&xevent, x, y, w, h);
    if (dnd_version_at_least (dnd->dragging_version, 2))
	if (will_accept)
	    XDND_STATUS_ACTION (&xevent) = action;

    xdnd_send_event (dnd, window, &xevent);
}

void xdnd_send_leave (DndClass * dnd, Window window, Window from)
{
    XEvent xevent;

    memset (&xevent, 0, sizeof (xevent));

    xevent.xany.type = ClientMessage;
    xevent.xany.display = dnd->display;
    xevent.xclient.window = window;
    xevent.xclient.message_type = dnd->XdndLeave;
    xevent.xclient.format = 32;

    XDND_LEAVE_SOURCE_WIN (&xevent) = from;

    xdnd_send_event (dnd, window, &xevent);
}

void xdnd_send_drop (DndClass * dnd, Window window, Window from, unsigned long time)
{
    XEvent xevent;

    memset (&xevent, 0, sizeof (xevent));

    xevent.xany.type = ClientMessage;
    xevent.xany.display = dnd->display;
    xevent.xclient.window = window;
    xevent.xclient.message_type = dnd->XdndDrop;
    xevent.xclient.format = 32;

    XDND_DROP_SOURCE_WIN (&xevent) = from;
    if (dnd_version_at_least (dnd->dragging_version, 1))
	XDND_DROP_TIME (&xevent) = time;

    xdnd_send_event (dnd, window, &xevent);
}

/* error is not actually used, i think future versions of the protocol should return an error status
   to the calling window with the XdndFinished client message */
void xdnd_send_finished (DndClass * dnd, Window window, Window from, int error)
{
    XEvent xevent;

    memset (&xevent, 0, sizeof (xevent));

    xevent.xany.type = ClientMessage;
    xevent.xany.display = dnd->display;
    xevent.xclient.window = window;
    xevent.xclient.message_type = dnd->XdndFinished;
    xevent.xclient.format = 32;

    XDND_FINISHED_TARGET_WIN (&xevent) = from;

    xdnd_send_event (dnd, window, &xevent);
}

/* returns non-zero on error - i.e. no selection owner set. Type is of course the mime type */
int xdnd_convert_selection (DndClass * dnd, Window window, Window requester, Atom type)
{
    if (window != XGetSelectionOwner (dnd->display, dnd->XdndSelection)) {
        DEBUGOUT(_LtDebug(__FILE__, NULL,"xdnd_convert_selection(): XGetSelectionOwner failed"));
	return 1;
    }
    XConvertSelection (dnd->display, dnd->XdndSelection, type,
		    dnd->Xdnd_NON_PROTOCOL_ATOM, requester, CurrentTime);
    return 0;
}

/* returns non-zero on error */
int xdnd_set_selection_owner (DndClass * dnd, Window window, Atom type)
{
    if (!XSetSelectionOwner (dnd->display, dnd->XdndSelection, window, CurrentTime)) {
        DEBUGOUT(_LtDebug(__FILE__, NULL, "xdnd_set_selection_owner(): XSetSelectionOwner failed"));
	return 1;
    }
    return 0;
}

void xdnd_selection_send (DndClass * dnd, XSelectionRequestEvent * request, unsigned char *data, int length)
{
    XEvent xevent;
    DEBUGOUT(_LtDebug(__FILE__, NULL, "      requestor = %ld", request->requestor));
    DEBUGOUT(_LtDebug(__FILE__, NULL, "      property = %ld", request->property));
    DEBUGOUT(_LtDebug(__FILE__, NULL, "      length = %d", length));
    XChangeProperty (dnd->display, request->requestor, request->property,
		     request->target, 8, PropModeReplace, data, length);
    xevent.xselection.type = SelectionNotify;
    xevent.xselection.property = request->property;
    xevent.xselection.display = request->display;
    xevent.xselection.requestor = request->requestor;
    xevent.xselection.selection = request->selection;
    xevent.xselection.target = request->target;
    xevent.xselection.time = request->time;
    xdnd_send_event (dnd, request->requestor, &xevent);
}

/* respond to a notification that a primary selection has been sent */
int xdnd_get_selection (DndClass * dnd, Window from, Atom property, Window insert)
{
    long read;
    int error = 0;
    unsigned long remaining;
    if (!property)
	return 1;
    read = 0;
    do {
	unsigned char *s;
	Atom actual;
	int format;
	unsigned long count;
	if (XGetWindowProperty (dnd->display, insert, property, read / 4, 65536, 1,
				AnyPropertyType, &actual, &format,
				&count, &remaining,
				&s) != Success) {
	    XFree (s);
	    return 1;
	}
	read += count;
	if (dnd->widget_insert_drop && !error)
	    error = (*dnd->widget_insert_drop) (dnd, s, count, remaining, insert, from, actual);
	XFree (s);
    } while (remaining);
    return error;
}


int outside_rectangle (int x, int y, XRectangle * r)
{
    return (x < r->x || y < r->y || x >= r->x + r->width || y >= r->y + r->height);
}

/* avoids linking with the maths library */
static float xdnd_sqrt (float x)
{
    float last_ans, ans = 2, a;
    if (x <= 0.0)
	return 0.0;
    do {
	last_ans = ans;
	ans = (ans + x / ans) / 2;
	a = (ans - last_ans) / ans;
	if (a < 0.0)
	    a = (-a);
    } while (a > 0.001);
    return ans;
}

/* returns action on success, 0 otherwise */
Atom xdnd_drag (DndClass * dnd, Window from, Atom action, Atom * typelist)
{
    XEvent xevent, xevent_temp;
    Window over_window = 0, last_window = 0;
    int n;
    DndCursor *cursor;
    float x_mouse, y_mouse;
    int result = 0, dnd_aware;

    if (!typelist)
	_XmWarning(NULL, "xdnd_drag() called with typelist = 0");

/* first wait until the mouse moves more than five pixels */
    do {
	XNextEvent (dnd->display, &xevent);
	if (xevent.type == ButtonRelease) {
            DEBUGOUT(_LtDebug(__FILE__, NULL, "button release - no motion"));
	    XSendEvent (dnd->display, xevent.xany.window, 0, ButtonReleaseMask, &xevent);
	    return 0;
	}
    } while (xevent.type != MotionNotify);

    x_mouse = (float) xevent.xmotion.x_root;
    y_mouse = (float) xevent.xmotion.y_root;

    if (!dnd->drag_threshold)
	dnd->drag_threshold = 4.0;
    for (;;) {
	XNextEvent (dnd->display, &xevent);
	if (xevent.type == MotionNotify)
	    if (xdnd_sqrt ((x_mouse - xevent.xmotion.x_root) * (x_mouse - xevent.xmotion.x_root) +
			   (y_mouse - xevent.xmotion.y_root) * (y_mouse - xevent.xmotion.y_root)) > dnd->drag_threshold)
		break;
	if (xevent.type == ButtonRelease) {
	    XSendEvent (dnd->display, xevent.xany.window, 0, ButtonReleaseMask, &xevent);
	    return 0;
	}
    }

    DEBUGOUT(_LtDebug(__FILE__, NULL, "moved 5 pixels - going to drag"));

    n = array_length (typelist);
    if (n > XDND_THREE)
	xdnd_set_type_list (dnd, from, typelist);

    xdnd_reset (dnd);

    dnd->stage = XDND_DRAG_STAGE_DRAGGING;

    for (cursor = &dnd->cursors[0]; cursor->width; cursor++)
	if (cursor->action == action)
	    break;
    if (!cursor->width)
	cursor = &dnd->cursors[0];

/* the mouse has been dragged a little, so this is a drag proper */
    if (XGrabPointer (dnd->display, dnd->root_window, False,
		      ButtonMotionMask | PointerMotionMask | ButtonPressMask | ButtonReleaseMask,
		      GrabModeAsync, GrabModeAsync, None,
		      cursor->cursor, CurrentTime) != GrabSuccess)
        DEBUGOUT(_LtDebug(__FILE__, NULL, "Unable to grab pointer"));

    while (xevent.xany.type != ButtonRelease) {
	XAllowEvents (dnd->display, SyncPointer, CurrentTime);
	XNextEvent (dnd->display, &xevent);
	switch (xevent.type) {
	case Expose:
	    if (dnd->handle_expose_events)
		(*dnd->handle_expose_events) (dnd, &xevent);
	    break;
	case EnterNotify:
/* this event is not actually reported, so we find out by ourselves from motion events */
	    break;
	case LeaveNotify:
/* this event is not actually reported, so we find out by ourselves from motion events */
	    break;
	case ButtonRelease:
/* done, but must send a leave event */
            DEBUGOUT(_LtDebug(__FILE__, NULL, "ButtonRelease - exiting event loop"));
	    break;
	case MotionNotify:
	    memcpy (&xevent_temp, &xevent, sizeof (xevent));
	    if (!xevent.xmotion.subwindow) {
		xevent.xmotion.subwindow = xevent.xmotion.window;
	    } else {
		Window root_return, child_return;
		unsigned int mask_return;
		while (XQueryPointer (dnd->display, xevent.xmotion.subwindow, &root_return, &child_return,
				      &xevent.xmotion.x_root, &xevent.xmotion.y_root, &xevent.xmotion.x,
				      &xevent.xmotion.y, &mask_return)) {
		    if (!child_return)
			goto found_descendent;
		    xevent.xmotion.subwindow = child_return;
		}
		break;
	    }
	  found_descendent:
/* last_window is just for debug purposes */
	    if (last_window != xevent.xmotion.subwindow) {
                DEBUGOUT(_LtDebug(__FILE__, NULL, "window crossing to %ld", xevent.xmotion.subwindow));
                DEBUGOUT(_LtDebug(__FILE__, NULL, "  current window is %ld", over_window));
	    }
	    dnd_aware = 0;
/* is the new window dnd aware? if not stay in the old window */
	    if (over_window != xevent.xmotion.subwindow &&
		last_window != xevent.xmotion.subwindow &&
		(
		    (dnd_aware = xdnd_is_dnd_aware (dnd, xevent.xmotion.subwindow, &dnd->dragging_version, typelist)) ||
		    (dnd->options & XDND_OPTION_NO_HYSTERESIS)
		)) {
/* leaving window we were over */
		xevent.xany.window = over_window;
		if (over_window) {
		    if (dnd->stage == XDND_DRAG_STAGE_ENTERED) {
                        DEBUGOUT(_LtDebug(__FILE__, NULL, "got leave at right stage"));
			dnd->stage = XDND_DRAG_STAGE_DRAGGING;
			if (dnd->internal_drag) {
                            DEBUGOUT(_LtDebug(__FILE__, NULL, "  our own widget"));
			    if (dnd->widget_apply_leave)
				(*dnd->widget_apply_leave) (dnd, xevent.xany.window);
			} else {
                            DEBUGOUT(_LtDebug(__FILE__, NULL, "  not our widget - sending XdndLeave"));
			    xdnd_send_leave (dnd, xevent.xany.window, from);
			}
			dnd->internal_drag = 0;
			dnd->dropper_window = 0;
			dnd->ready_to_drop = 0;
		    } else {
			DEBUGOUT(_LtDebug(__FILE__, NULL, "got leave at wrong stage - ignoring"));
		    }
		}
/* entering window we are currently over */
		over_window = xevent.xmotion.subwindow;
		if (dnd_aware) {
		    DEBUGOUT(_LtDebug(__FILE__, NULL, "  is dnd aware"));
		    dnd->stage = XDND_DRAG_STAGE_ENTERED;
		    if (dnd->widget_exists && (*dnd->widget_exists) (dnd, over_window))
			dnd->internal_drag = 1;
		    if (dnd->internal_drag) {
			DEBUGOUT(_LtDebug(__FILE__, NULL, "    our own widget"));
		    } else {
			DEBUGOUT(_LtDebug(__FILE__, NULL, "    not our widget - sending XdndEnter"));
			xdnd_send_enter (dnd, over_window, from, typelist);
		    }
		    dnd->want_position = 1;
		    dnd->ready_to_drop = 0;
		    dnd->rectangle.width = dnd->rectangle.height = 0;
		    dnd->dropper_window = over_window;
/* we want an additional motion event in case the pointer enters and then stops */
		    XSendEvent (dnd->display, from, 0, ButtonMotionMask, &xevent_temp);
		    XSync (dnd->display, 0);
		}
/* we are now officially in a new window */
	    } else {
/* got here, so we are just moving `inside' the same window */
		if (dnd->stage == XDND_DRAG_STAGE_ENTERED) {
		    dnd->supported_action = dnd->XdndActionCopy;
		    DEBUGOUT(_LtDebug(__FILE__, NULL, "got motion at right stage"));
		    dnd->x = xevent.xmotion.x_root;
		    dnd->y = xevent.xmotion.y_root;
		    if (dnd->want_position && outside_rectangle (dnd->x, dnd->y, &dnd->rectangle)) {
			DEBUGOUT(_LtDebug(__FILE__, NULL, "  want position and outside rectangle"));
			if (dnd->internal_drag) {
			    DEBUGOUT(_LtDebug(__FILE__, NULL, "    our own widget"));
			    dnd->ready_to_drop = (*dnd->widget_apply_position) (dnd, over_window, from,
										action, dnd->x, dnd->y, xevent.xmotion.time, typelist,
										&dnd->want_position, &dnd->supported_action, &dnd->desired_type, &dnd->rectangle);
			    /* if not ready, keep sending positions, this check is repeated below for XdndStatus from external widgets */
			    if (!dnd->ready_to_drop) {
				dnd->want_position = 1;
				dnd->rectangle.width = dnd->rectangle.height = 0;
			    }
			    DEBUGOUT(_LtDebug(__FILE__, NULL, "      return action=%ld", dnd->supported_action));
			} else {
			    DEBUGOUT(_LtDebug(__FILE__, NULL, "    not our own widget - sending XdndPosition"));
			    xdnd_send_position (dnd, over_window, from, action, dnd->x, dnd->y, xevent.xmotion.time);
			}
		    } else {
			DEBUGOUT(_LtDebug(__FILE__, NULL, "  doesn't want position or inside rectangle"));
			DEBUGOUT(_LtDebug(__FILE__, NULL, "    rectangle = (x=%d, y=%d, w=%d, h=%d), (x,y)=(%d,%d) want_position=%d\n", dnd->rectangle.x, dnd->rectangle.y, dnd->rectangle.width, dnd->rectangle.height, dnd->x, dnd->y, dnd->want_position));
		    }
		}
	    }
	    last_window = xevent.xmotion.subwindow;
	    break;
	case ClientMessage:
	    DEBUGOUT(_LtDebug(__FILE__, NULL, "ClientMessage recieved"));
	    if (xevent.xclient.message_type == dnd->XdndStatus && !dnd->internal_drag) {
		DEBUGOUT(_LtDebug(__FILE__, NULL, "  XdndStatus recieved"));
		if (dnd->stage == XDND_DRAG_STAGE_ENTERED && XDND_STATUS_TARGET_WIN (&xevent) == dnd->dropper_window) {
		    DEBUGOUT(_LtDebug(__FILE__, NULL, "    XdndStatus stage correct, dropper window correct"));
		    dnd->want_position = XDND_STATUS_WANT_POSITION (&xevent);
		    dnd->ready_to_drop = XDND_STATUS_WILL_ACCEPT (&xevent);
		    dnd->rectangle.x = XDND_STATUS_RECT_X (&xevent);
		    dnd->rectangle.y = XDND_STATUS_RECT_Y (&xevent);
		    dnd->rectangle.width = XDND_STATUS_RECT_WIDTH (&xevent);
		    dnd->rectangle.height = XDND_STATUS_RECT_HEIGHT (&xevent);
		    dnd->supported_action = dnd->XdndActionCopy;
		    if (dnd_version_at_least (dnd->dragging_version, 2))
			dnd->supported_action = XDND_STATUS_ACTION (&xevent);
		    DEBUGOUT(_LtDebug(__FILE__, NULL, "      return action=%ld", dnd->supported_action));
		    /* if not ready, keep sending positions, this check is repeated above for internal widgets */
		    if (!dnd->ready_to_drop) {
			dnd->want_position = 1;
			dnd->rectangle.width = dnd->rectangle.height = 0;
		    }
		    DEBUGOUT(_LtDebug(__FILE__, NULL, "      rectangle = (x=%d, y=%d, w=%d, h=%d), want_position=%d\n", dnd->rectangle.x, dnd->rectangle.y, dnd->rectangle.width, dnd->rectangle.height, dnd->want_position));
		} else {
		    DEBUGOUT(_LtDebug(__FILE__, NULL, "    XdndStatus stage incorrect or dropper window incorrect"));
		}
	    }
	    break;
	case SelectionRequest:{
/* the target widget MAY request data, so wait for SelectionRequest */
		int length = 0;
		unsigned char *data = 0;
		DEBUGOUT(_LtDebug(__FILE__, NULL, "SelectionRequest - getting widget data"));

		(*dnd->widget_get_data) (dnd, from, &data, &length, xevent.xselectionrequest.target);
		if (data) {
		    DEBUGOUT(_LtDebug(__FILE__, NULL, "  sending selection"));
		    xdnd_selection_send (dnd, &xevent.xselectionrequest, data, length);
		    xdnd_xfree (data);
		}
	    }
	    break;
	}
    }

    if (dnd->ready_to_drop) {
	Time time;
	DEBUGOUT(_LtDebug(__FILE__, NULL, "ready_to_drop - sending XdndDrop"));
	time = xevent.xbutton.time;
	if (dnd->internal_drag) {
/* we are dealing with our own widget, no need to send drop events, just put the data straight */
	    int length = 0;
	    unsigned char *data = 0;
	    if (dnd->widget_insert_drop) {
		(*dnd->widget_get_data) (dnd, from, &data, &length, dnd->desired_type);
		if (data) {
		    if (!(*dnd->widget_insert_drop) (dnd, data, length, 0, dnd->dropper_window, from, dnd->desired_type)) {
			result = dnd->supported_action;		/* success - so return action to caller */
			DEBUGOUT(_LtDebug(__FILE__, NULL, "  inserted data into widget - success"));
		    } else {
			DEBUGOUT(_LtDebug(__FILE__, NULL, "  inserted data into widget - failed"));
		    }
		    xdnd_xfree (data);
		} else {
		    DEBUGOUT(_LtDebug(__FILE__, NULL, "  got data from widget, but data is null"));
		}
	    }
	} else {
	    xdnd_set_selection_owner (dnd, from, dnd->desired_type);
	    xdnd_send_drop (dnd, dnd->dropper_window, from, time);
	}
	if (!dnd->internal_drag)
	    for (;;) {
		XAllowEvents (dnd->display, SyncPointer, CurrentTime);
		XNextEvent (dnd->display, &xevent);
		if (xevent.type == ClientMessage && xevent.xclient.message_type == dnd->XdndFinished) {
		    DEBUGOUT(_LtDebug(__FILE__, NULL, "XdndFinished"));
		    if (XDND_FINISHED_TARGET_WIN (&xevent) == dnd->dropper_window) {
			DEBUGOUT(_LtDebug(__FILE__, NULL, "  source correct - exiting event loop, action=%ld", dnd->supported_action));
			result = dnd->supported_action;		/* success - so return action to caller */
			break;
		    }
		} else if (xevent.type == Expose) {
		    if (dnd->handle_expose_events)
			(*dnd->handle_expose_events) (dnd, &xevent);
		} else if (xevent.type == MotionNotify) {
		    if (xevent.xmotion.time > time + (dnd->time_out ? dnd->time_out * 1000 : 10000)) {	/* allow a ten second timeout as default */
			DEBUGOUT(_LtDebug(__FILE__, NULL, "timeout - exiting event loop"));
			break;
		    }
		} else if (xevent.type == SelectionRequest && xevent.xselectionrequest.selection == dnd->XdndSelection) {
/* the target widget is going to request data, so check for SelectionRequest events */
		    int length = 0;
		    unsigned char *data = 0;

		    DEBUGOUT(_LtDebug(__FILE__, NULL, "SelectionRequest - getting widget data"));
		    (*dnd->widget_get_data) (dnd, from, &data, &length, xevent.xselectionrequest.target);
		    if (data) {
			DEBUGOUT(_LtDebug(__FILE__, NULL, "  sending selection"));
			xdnd_selection_send (dnd, &xevent.xselectionrequest, data, length);
			xdnd_xfree (data);
		    }
/* don't wait for a XdndFinished event */
		    if (!dnd_version_at_least (dnd->dragging_version, 2))
			break;
		}
	    }
    } else {
	DEBUGOUT(_LtDebug(__FILE__, NULL, "not ready_to_drop - ungrabbing pointer"));
    }
    XUngrabPointer (dnd->display, CurrentTime);
    xdnd_reset (dnd);
    return result;
}

/* returns non-zero if event is handled */
int xdnd_handle_drop_events (DndClass * dnd, XEvent * xevent)
{
    int result = 0;
    if (xevent->type == SelectionNotify) {
	DEBUGOUT(_LtDebug(__FILE__, NULL, "got SelectionNotify"));
	if (xevent->xselection.property == dnd->Xdnd_NON_PROTOCOL_ATOM && dnd->stage == XDND_DROP_STAGE_CONVERTING) {
	    int error;
	    DEBUGOUT(_LtDebug(__FILE__, NULL, "  property is Xdnd_NON_PROTOCOL_ATOM - getting selection"));
	    error = xdnd_get_selection (dnd, dnd->dragger_window, xevent->xselection.property, xevent->xany.window);
/* error is not actually used, i think future versions of the protocol maybe should return
   an error status to the calling window with the XdndFinished client message */
	    if (dnd_version_at_least (dnd->dragging_version, 2))
		xdnd_send_finished (dnd, dnd->dragger_window, dnd->dropper_window, error);
	    xdnd_xfree (dnd->dragger_typelist);
	    xdnd_reset (dnd);
	    dnd->stage = XDND_DROP_STAGE_IDLE;
	    result = 1;
	} else {
	    DEBUGOUT(_LtDebug(__FILE__, NULL, "  property is not Xdnd_NON_PROTOCOL_ATOM - ignoring"));
	}
    } else if (xevent->type == ClientMessage) {
	DEBUGOUT(_LtDebug(__FILE__, NULL, "got ClientMessage"));
	if (xevent->xclient.message_type == dnd->XdndEnter) {
	    DEBUGOUT(_LtDebug(__FILE__, NULL, "  message_type is XdndEnter"));
	    xdnd_reset (dnd);
	    dnd->dragger_window = XDND_ENTER_SOURCE_WIN (xevent);
	    dnd->dropper_window = xevent->xany.window;
	    xdnd_xfree (dnd->dragger_typelist);
	    if (XDND_ENTER_THREE_TYPES (xevent)) {
		DEBUGOUT(_LtDebug(__FILE__, NULL, "    three types only"));
		xdnd_get_three_types (dnd, xevent, &dnd->dragger_typelist);
	    } else {
		DEBUGOUT(_LtDebug(__FILE__, NULL, "    more than three types - getting list"));
		xdnd_get_type_list (dnd, dnd->dragger_window, &dnd->dragger_typelist);
	    }
	    if (dnd->dragger_typelist)
		dnd->stage = XDND_DROP_STAGE_ENTERED;
	    else
		DEBUGOUT(_LtDebug(__FILE__, NULL, "      typelist returned as zero!"));
	    dnd->dragging_version = XDND_ENTER_VERSION (xevent);
	    result = 1;
	} else if (xevent->xclient.message_type == dnd->XdndLeave) {
	    DEBUGOUT(_LtDebug(__FILE__, NULL, "  message_type is XdndLeave"));
	    if (dnd->dragger_window == XDND_LEAVE_SOURCE_WIN (xevent) && dnd->stage == XDND_DROP_STAGE_ENTERED) {
		DEBUGOUT(_LtDebug(__FILE__, NULL, "    leaving"));
		if (dnd->widget_apply_leave)
		    (*dnd->widget_apply_leave) (dnd, xevent->xany.window);
		dnd->stage = XDND_DROP_STAGE_IDLE;
		xdnd_xfree (dnd->dragger_typelist);
		result = 1;
	    } else {
		DEBUGOUT(_LtDebug(__FILE__, NULL, "    wrong stage or from wrong window"));
	    }
	} else if (xevent->xclient.message_type == dnd->XdndPosition) {
	    DEBUGOUT(_LtDebug(__FILE__, NULL, "  message_type is XdndPosition"));
	    if (dnd->dragger_window == XDND_POSITION_SOURCE_WIN (xevent) && dnd->stage == XDND_DROP_STAGE_ENTERED) {
		int want_position;
		Atom action;
		XRectangle rectangle;
		action = dnd->XdndActionCopy;
		dnd->supported_action = dnd->XdndActionCopy;
		dnd->x = XDND_POSITION_ROOT_X (xevent);
		dnd->y = XDND_POSITION_ROOT_Y (xevent);
		dnd->time = CurrentTime;
		if (dnd_version_at_least (dnd->dragging_version, 1))
		    dnd->time = XDND_POSITION_TIME (xevent);
		if (dnd_version_at_least (dnd->dragging_version, 1))
		    action = XDND_POSITION_ACTION (xevent);
		dnd->will_accept = (*dnd->widget_apply_position) (dnd, xevent->xany.window, dnd->dragger_window,
		action, dnd->x, dnd->y, dnd->time, dnd->dragger_typelist,
								  &want_position, &dnd->supported_action, &dnd->desired_type, &rectangle);
		DEBUGOUT(_LtDebug(__FILE__, NULL, "    will accept = %d", dnd->will_accept));
		DEBUGOUT(_LtDebug(__FILE__, NULL, "    sending status"));
		DEBUGOUT(_LtDebug(__FILE__, NULL, "      action=%ld, rectangle = (x=%d, y=%d, w=%d, h=%d), (x,y)=(%d,%d) want_position=%d\n", dnd->supported_action, rectangle.x, rectangle.y, rectangle.width, rectangle.height, dnd->x, dnd->y, want_position));
		xdnd_send_status (dnd, dnd->dragger_window, xevent->xany.window, dnd->will_accept,
				  want_position, rectangle.x, rectangle.y, rectangle.width, rectangle.height, dnd->supported_action);
		result = 1;
	    } else {
		DEBUGOUT(_LtDebug(__FILE__, NULL, "    wrong stage or from wrong window"));
	    }
	} else if (xevent->xclient.message_type == dnd->XdndDrop) {
	    DEBUGOUT(_LtDebug(__FILE__, NULL, "  message_type is XdndDrop"));
	    if (dnd->dragger_window == XDND_DROP_SOURCE_WIN (xevent) && dnd->stage == XDND_DROP_STAGE_ENTERED) {
		dnd->time = CurrentTime;
		if (dnd_version_at_least (dnd->dragging_version, 1))
		    dnd->time = XDND_DROP_TIME (xevent);
		if (dnd->will_accept) {
		    DEBUGOUT(_LtDebug(__FILE__, NULL, "    will_accept is true - converting selectiong"));
		    DEBUGOUT(_LtDebug(__FILE__, NULL, "      my window is %ld", dnd->dropper_window));
		    DEBUGOUT(_LtDebug(__FILE__, NULL, "        source window is %ld", dnd->dragger_window));
		    xdnd_convert_selection (dnd, dnd->dragger_window, dnd->dropper_window, dnd->desired_type);
		    dnd->stage = XDND_DROP_STAGE_CONVERTING;
		} else {
		    DEBUGOUT(_LtDebug(__FILE__, NULL, "    will_accept is false - sending finished"));
		    if (dnd_version_at_least (dnd->dragging_version, 1))
			xdnd_send_finished (dnd, dnd->dragger_window, xevent->xany.window, 1);
		    xdnd_xfree (dnd->dragger_typelist);
		    xdnd_reset (dnd);
		    dnd->stage = XDND_DROP_STAGE_IDLE;
		}
		result = 1;
	    } else {
		DEBUGOUT(_LtDebug(__FILE__, NULL, "    wrong stage or from wrong window"));
	    }
	}
    }
    return result;
}

/*
   Following here is a sample implementation: Suppose we want a window
   to recieve drops, but do not want to be concerned with setting up all
   the DndClass methods. All we then do is call xdnd_get_drop() whenever a
   ClientMessage is recieved. If the message has nothing to do with XDND,
   xdnd_get_drop quickly returns 0. If it is a XdndEnter message, then
   xdnd_get_drop enters its own XNextEvent loop and handles all XDND
   protocol messages internally, returning the action requested.

   You should pass a desired typelist and actionlist to xdnd_get_type.
   These must be null terminated arrays of atoms, or a null pointer
   if you would like any action or type to be accepted. If typelist
   is null then the first type of the dragging widgets typelist will
   be the one used. If actionlist is null, then only XdndActionCopy will
   be accepted.

   The result is stored in *data, length, type, x and y.
   *data must be free'd.
 */

struct xdnd_get_drop_info {
    unsigned char *drop_data;
    int drop_data_length;
    int x, y;
    Atom return_type;
    Atom return_action;
    Atom *typelist;
    Atom *actionlist;
};

static int widget_insert_drop (DndClass * dnd, unsigned char *data, int length, int remaining, Window into, Window from, Atom type)
{
    struct xdnd_get_drop_info *i;
    i = (struct xdnd_get_drop_info *) dnd->user_hook1;
    if (!i->drop_data) {
	i->drop_data = malloc (length);
	if (!i->drop_data)
	    return 1;
	memcpy (i->drop_data, data, length);
	i->drop_data_length = length;
    } else {
	unsigned char *t;
	t = malloc (i->drop_data_length + length);
	if (!t) {
	    free (i->drop_data);
	    i->drop_data = 0;
	    return 1;
	}
	memcpy (t, i->drop_data, i->drop_data_length);
	memcpy (t + i->drop_data_length, data, length);
	free (i->drop_data);
	i->drop_data = t;
	i->drop_data_length += length;
    }
    return 0;
}

static int widget_apply_position (DndClass * dnd, Window widgets_window, Window from,
		      Atom action, int x, int y, Time t, Atom * typelist,
 int *want_position, Atom * supported_action_return, Atom * desired_type,
				  XRectangle * rectangle)
{
    int i, j;
    struct xdnd_get_drop_info *info;
    Atom *dropper_typelist, supported_type = 0;
    Atom *supported_actions, supported_action = 0;

    info = (struct xdnd_get_drop_info *) dnd->user_hook1;
    dropper_typelist = info->typelist;
    supported_actions = info->actionlist;

    if (dropper_typelist) {
/* find a correlation: */
	for (j = 0; dropper_typelist[j]; j++) {
	    for (i = 0; typelist[i]; i++) {
		if (typelist[i] == dropper_typelist[j]) {
		    supported_type = typelist[i];
		    break;
		}
	    }
	    if (supported_type)
		break;
	}
    } else {
/* user did not specify, so return first type */
	supported_type = typelist[0];
    }
/* not supported, so return false */
    if (!supported_type)
	return 0;

    if (supported_actions) {
	for (j = 0; supported_actions[j]; j++) {
	    if (action == supported_actions[j]) {
		supported_action = action;
		break;
	    }
	}
    } else {
/* user did not specify */
	if (action == dnd->XdndActionCopy)
	    supported_action = action;
    }
    if (!supported_action)
	return 0;

    *want_position = 1;
    rectangle->x = rectangle->y = 0;
    rectangle->width = rectangle->height = 0;

    info->return_action = *supported_action_return = supported_action;
    info->return_type = *desired_type = supported_type;
    info->x = x;
    info->y = y;

    return 1;
}

Atom xdnd_get_drop (Display * display, XEvent * xevent, Atom * typelist, Atom * actionlist,
	  unsigned char **data, int *length, Atom * type, int *x, int *y)
{
    Atom action = 0;
    static int initialised = 0;
    static DndClass dnd;
    if (!initialised) {
	xdnd_init (&dnd, display);
	initialised = 1;
    }
    if (xevent->type != ClientMessage || xevent->xclient.message_type != dnd.XdndEnter) {
	return 0;
    } else {
	struct xdnd_get_drop_info i;

/* setup user structure */
	memset (&i, 0, sizeof (i));
	i.typelist = actionlist;
	i.typelist = typelist;
	dnd.user_hook1 = &i;

/* setup methods */
	dnd.widget_insert_drop = widget_insert_drop;
	dnd.widget_apply_position = widget_apply_position;

/* main loop */
	for (;;) {
	    xdnd_handle_drop_events (&dnd, xevent);
	    if (dnd.stage == XDND_DROP_STAGE_IDLE)
		break;
	    XNextEvent (dnd.display, xevent);
	}

/* return results */
	if (i.drop_data) {
	    *length = i.drop_data_length;
	    *data = i.drop_data;
	    action = i.return_action;
	    *type = i.return_type;
	    *x = i.x;
	    *y = i.y;
	}
    }
    return action;
}