gdkdnd.c

gtk是linux一款强大的夸平台的图形化开发工具

  gint old_warnings = gdk_error_warnings;
  
  gdk_error_code = 0;
  gdk_error_warnings = 0;

  tmp_list = cache->children;

  while (tmp_list && !retval)
    {
      GdkCacheChild *child = tmp_list->data;

      if ((child->xid != ignore) && (child->mapped))
	{
	  if ((x_root >= child->x) && (x_root < child->x + child->width) &&
	      (y_root >= child->y) && (y_root < child->y + child->height))
	    {
	      retval = get_client_window_at_coords_recurse (child->xid,
							    x_root - child->x, 
							    y_root - child->y);
	      if (!retval)
		retval = child->xid;
	    }
	  
	}
      tmp_list = tmp_list->next;
    }

  gdk_error_warnings = old_warnings;
  if (retval)
    return retval;
  else
    return gdk_root_window;
}

#if 0
static Window
get_client_window_at_coords_recurse (Window  win,
				     gint    x_root,
				     gint    y_root)
{
  Window child;
  Atom type = None;
  int format;
  unsigned long nitems, after;
  unsigned char *data;
  int dest_x, dest_y;
  
  static Atom wm_state_atom = None;

  if (!wm_state_atom)
    wm_state_atom = gdk_atom_intern ("WM_STATE", FALSE);
    
  XGetWindowProperty (gdk_display, win, 
		      wm_state_atom, 0, 0, False, AnyPropertyType,
		      &type, &format, &nitems, &after, &data);
  
  if (gdk_error_code)
    {
      gdk_error_code = 0;

      return None;
    }

  if (type != None)
    {
      XFree (data);
      return win;
    }

  XTranslateCoordinates (gdk_display, gdk_root_window, win,
			 x_root, y_root, &dest_x, &dest_y, &child);

  if (gdk_error_code)
    {
      gdk_error_code = 0;

      return None;
    }

  if (child)
    return get_client_window_at_coords_recurse (child, x_root, y_root);
  else
    return None;
}

static Window 
get_client_window_at_coords (Window  ignore,
			     gint    x_root,
			     gint    y_root)
{
  Window root, parent, *children;
  unsigned int nchildren;
  int i;
  Window retval = None;
  
  gint old_warnings = gdk_error_warnings;
  
  gdk_error_code = 0;
  gdk_error_warnings = 0;

  if (XQueryTree(gdk_display, gdk_root_window, 
		 &root, &parent, &children, &nchildren) == 0)
    return 0;

  for (i = nchildren - 1; (i >= 0) && (retval == None); i--)
    {
      if (children[i] != ignore)
	{
	  XWindowAttributes xwa;

	  XGetWindowAttributes (gdk_display, children[i], &xwa);

	  if (gdk_error_code)
	    gdk_error_code = 0;
	  else if ((xwa.map_state == IsViewable) &&
		   (x_root >= xwa.x) && (x_root < xwa.x + (gint)xwa.width) &&
		   (y_root >= xwa.y) && (y_root < xwa.y + (gint)xwa.height))
	    {
	      retval = get_client_window_at_coords_recurse (children[i],
							    x_root, y_root);
	      if (!retval)
		retval = children[i];
	    }
	}
    }

  XFree (children);

  gdk_error_warnings = old_warnings;
  if (retval)
    return retval;
  else
    return gdk_root_window;
}
#endif

/*************************************************************
 ***************************** MOTIF *************************
 *************************************************************/

/* values used in the message type for Motif DND */
enum {
    XmTOP_LEVEL_ENTER,
    XmTOP_LEVEL_LEAVE,
    XmDRAG_MOTION,
    XmDROP_SITE_ENTER,
    XmDROP_SITE_LEAVE,
    XmDROP_START,
    XmDROP_FINISH,
    XmDRAG_DROP_FINISH,
    XmOPERATION_CHANGED
};

/* Values used to specify type of protocol to use */
enum {
    XmDRAG_NONE,
    XmDRAG_DROP_ONLY,
    XmDRAG_PREFER_PREREGISTER,
    XmDRAG_PREREGISTER,
    XmDRAG_PREFER_DYNAMIC,
    XmDRAG_DYNAMIC,
    XmDRAG_PREFER_RECEIVER
};

/* Operation codes */
enum {
  XmDROP_NOOP,
  XmDROP_MOVE = 0x01,
  XmDROP_COPY = 0x02,
  XmDROP_LINK = 0x04
};

/* Drop site status */
enum {
  XmNO_DROP_SITE = 0x01,
  XmDROP_SITE_INVALID = 0x02,
  XmDROP_SITE_VALID = 0x03
};

/* completion status */
enum {
  XmDROP,
  XmDROP_HELP,
  XmDROP_CANCEL,
  XmDROP_INTERRUPT
};

/* Static data for MOTIF DND */
static GList **motif_target_lists = NULL;
static gint motif_n_target_lists = -1;

/* Byte swapping routines. The motif specification leaves it
 * up to us to save a few bytes in the client messages
 */
static gchar local_byte_order = '\0';

#ifdef G_ENABLE_DEBUG
static void
print_target_list (GList *targets)
{
  while (targets)
    {
      gchar *name = gdk_atom_name (GPOINTER_TO_INT (targets->data));
      g_message ("\t%s", name);
      g_free (name);
      targets = targets->next;
    }
}
#endif /* G_ENABLE_DEBUG */

static void
init_byte_order (void)
{
  guint32 myint = 0x01020304;
  local_byte_order = (*(gchar *)&myint == 1) ? 'B' : 'l';
}

static guint16
card16_to_host (guint16 x, gchar byte_order) {
  if (byte_order == local_byte_order)
    return x;
  else
    return (x << 8) | (x >> 8);
}

static guint32
card32_to_host (guint32 x, gchar byte_order) {
  if (byte_order == local_byte_order)
    return x;
  else
    return (x << 24) | ((x & 0xff00) << 8) | ((x & 0xff0000) >> 8) | (x >> 24);
}

/* Motif packs together fields of varying length into the
 * client message. We can't rely on accessing these
 * through data.s[], data.l[], etc, because on some architectures
 * (i.e., Alpha) these won't be valid for format == 8. 
 */

#define MOTIF_XCLIENT_BYTE(xevent,i) \
  (xevent)->xclient.data.b[i]
#define MOTIF_XCLIENT_SHORT(xevent,i) \
  ((gint16 *)&((xevent)->xclient.data.b[0]))[i]
#define MOTIF_XCLIENT_LONG(xevent,i) \
  ((gint32 *)&((xevent)->xclient.data.b[0]))[i]

#define MOTIF_UNPACK_BYTE(xevent,i) MOTIF_XCLIENT_BYTE(xevent,i)
#define MOTIF_UNPACK_SHORT(xevent,i) \
  card16_to_host (MOTIF_XCLIENT_SHORT(xevent,i), MOTIF_XCLIENT_BYTE(xevent, 1))
#define MOTIF_UNPACK_LONG(xevent,i) \
  card32_to_host (MOTIF_XCLIENT_LONG(xevent,i), MOTIF_XCLIENT_BYTE(xevent, 1))

/***** Dest side ***********/

/* Property placed on source windows */
typedef struct _MotifDragInitiatorInfo {
  guint8 byte_order;
  guint8 protocol_version;
  guint16 targets_index;
  guint32 selection_atom;
} MotifDragInitiatorInfo;

/* Header for target table on the drag window */
typedef struct _MotifTargetTableHeader {
  guchar byte_order;
  guchar protocol_version;
  guint16 n_lists;
  guint32 total_size;
} MotifTargetTableHeader;

/* Property placed on target windows */
typedef struct _MotifDragReceiverInfo {
  guint8 byte_order;
  guint8 protocol_version;
  guint8 protocol_style;
  guint8 pad;
  guint32 proxy_window;
  guint16 num_drop_sites;
  guint16 padding;
  guint32 total_size;
} MotifDragReceiverInfo;

static Window motif_drag_window = None;
static GdkWindow *motif_drag_gdk_window = NULL;

static GdkAtom motif_drag_targets_atom = GDK_NONE;
static GdkAtom motif_drag_receiver_info_atom = GDK_NONE;

/* Target table handling */

GdkFilterReturn
motif_drag_window_filter (GdkXEvent *xevent,
			  GdkEvent  *event,
			  gpointer data)
{
  XEvent *xev = (XEvent *)xevent;

  switch (xev->xany.type)
    {
    case DestroyNotify:
      motif_drag_window = None;
      motif_drag_gdk_window = NULL;
      break;
    case PropertyNotify:
      if (motif_target_lists &&
	  motif_drag_targets_atom &&
	  (xev->xproperty.atom == motif_drag_targets_atom))
	motif_read_target_table();
      break;
    }
  return GDK_FILTER_REMOVE;
}

static Atom motif_drag_window_atom = GDK_NONE;

static Window
motif_lookup_drag_window (Display *display)
{
  Window retval = None;
  gulong bytes_after, nitems;
  GdkAtom type;
  gint format;
  guchar *data;

  XGetWindowProperty (gdk_display, gdk_root_window, motif_drag_window_atom,
		      0, 1, FALSE,
		      XA_WINDOW, &type, &format, &nitems, &bytes_after,
		      &data);
  
  if ((format == 32) && (nitems == 1) && (bytes_after == 0))
    {
      retval = *(Window *)data;
      GDK_NOTE(DND, 
	       g_message ("Found drag window %#lx\n", motif_drag_window));
    }

  if (type != None)
    XFree (data);

  return retval;
}

/* Finds the window where global Motif drag information is stored.
 * If it doesn't exist and 'create' is TRUE, create one.
 */
Window 
motif_find_drag_window (gboolean create)
{
  if (!motif_drag_window)
    {
      if (!motif_drag_window_atom)
	motif_drag_window_atom = gdk_atom_intern ("_MOTIF_DRAG_WINDOW", TRUE);

      motif_drag_window = motif_lookup_drag_window (gdk_display);
      
      if (!motif_drag_window && create)
	{
	  /* Create a persistant window. (Copied from LessTif) */
	  
	  Display *display;
	  XSetWindowAttributes attr;
	  display = XOpenDisplay (gdk_display_name);
	  XSetCloseDownMode (display, RetainPermanent);

	  XGrabServer (display);
	  
	  motif_drag_window = motif_lookup_drag_window (display);

	  if (!motif_drag_window)
	    {
	      attr.override_redirect = True;
	      attr.event_mask = PropertyChangeMask;
	      
	      motif_drag_window = 
		XCreateWindow(display, DefaultRootWindow(display),
			      -100, -100, 10, 10, 0, 0,
			      InputOnly, CopyFromParent,
			      (CWOverrideRedirect | CWEventMask), &attr);
	      
	      GDK_NOTE (DND,
			g_message ("Created drag window %#lx\n", motif_drag_window));
	      
	      XChangeProperty (display, gdk_root_window,
			       motif_drag_window_atom, XA_WINDOW,
			       32, PropModeReplace,
			       (guchar *)&motif_drag_window_atom, 1);

	    }
	  XUngrabServer (display);
	  XCloseDisplay (display);
	}

      /* There is a miniscule race condition here if the drag window
       * gets destroyed exactly now.
       */
      if (motif_drag_window)
	{
	  motif_drag_gdk_window = gdk_window_foreign_new (motif_drag_window);
	  gdk_window_add_filter (motif_drag_gdk_window,
				 motif_drag_window_filter,
				 NULL);
	}
    }

  return motif_drag_window;
}

static void 
motif_read_target_table (void)
{
  gulong bytes_after, nitems;
  GdkAtom type;
  gint format;
  gint i, j;

  if (!motif_drag_targets_atom)
    motif_drag_targets_atom = gdk_atom_intern ("_MOTIF_DRAG_TARGETS", FALSE);

  if (motif_target_lists)
    {
      for (i=0; i<motif_n_target_lists; i++)
	g_list_free (motif_target_lists[i]);
      
      g_free (motif_target_lists);
      motif_target_lists = NULL;
      motif_n_target_lists = 0;
    }

  if (motif_find_drag_window (FALSE))
    {
      MotifTargetTableHeader *header = NULL;
      guchar *target_bytes = NULL;
      guchar *p;
      gboolean success = FALSE;

      XGetWindowProperty (gdk_display, motif_drag_window, 
			  motif_drag_targets_atom,
			  0, (sizeof(MotifTargetTableHeader)+3)/4, FALSE,
			  motif_drag_targets_atom, 
			  &type, &format, &nitems, &bytes_after,
			  (guchar **)&header);

      if ((format != 8) || (nitems < sizeof (MotifTargetTableHeader)))
	goto error;

      header->n_lists = card16_to_host (header->n_lists, header->byte_order);
      header->total_size = card32_to_host (header->total_size, header->byte_order);

      XGetWindowProperty (gdk_display, motif_drag_window, motif_drag_targets_atom,
			  (sizeof(MotifTargetTableHeader)+3)/4, 
			  (header->total_size + 3)/4 - (sizeof(MotifTargetTableHeader) + 3)/4,
			  FALSE,
			  motif_drag_targets_atom, &type, &format, &nitems, 
			  &bytes_after, &target_bytes);
      
      if ((format != 8) || (bytes_after != 0) || 
	  (nitems != header->total_size - sizeof(MotifTargetTableHeader)))
	  goto error;

      motif_n_target_lists = header->n_lists;
      motif_target_lists = g_new0 (GList *, motif_n_target_lists);

      p = target_bytes;
      for (i=0; i<header->n_lists; i++)
	{
	  gint n_targets;
	  guint32 *targets;
	  
	  if (p + sizeof(guint16) - target_bytes > nitems)
	    goto error;

	  n_targets = card16_to_host (*(gushort *)p, header->byte_order);

	  /* We need to make a copy of the targets, since it may
	   * be unaligned
	   */
	  targets = g_new (guint32, n_targets);
	  memcpy (targets, p + sizeof(guint16), sizeof(guint32) * n_targets);

	  p +=  sizeof(guint16) + n_targets * sizeof(guint32);
	  if (p - target_bytes > nitems)
	    goto error;

	  for (j=0; j<n_targets; j++)
	    motif_target_lists[i] = 
	      g_list_prepend (motif_target_lists[i],
			      GUINT_TO_POINTER (card32_to_host (targets[j], 
								header->byte_order)));
	  g_free (targets);
	  motif_target_lists[i] = g_list_reverse (motif_target_lists[i]);
	}

      success = TRUE;
      
    error:
      if (header)
	XFree (header);
      
      if (target_bytes)
	XFree (target_bytes);

      if (!success)
	{
	  if (motif_target_lists)
	    {
	      g_free (motif_target_lists);
	      motif_target_lists = NULL;
	      motif_n_target_lists = 0;
	    }
	  g_warning ("Error reading Motif target table\n");
	}
    }
}