gdkevents.c

gtk是linux一款强大的夸平台的图形化开发工具

GdkEvent*
gdk_event_get (void)
{
  gdk_events_queue ();

  return gdk_event_unqueue ();
}

/*
 *--------------------------------------------------------------
 * gdk_event_peek
 *
 *   Gets the next event.
 *
 * Arguments:
 *
 * Results:
 *   If an event is waiting that we care about, returns 
 *   a copy of that event, but does not remove it from
 *   the queue. The pointer is to be freed with gdk_event_free.
 *   Otherwise, returns NULL.
 *
 * Side effects:
 *
 *--------------------------------------------------------------
 */

GdkEvent*
gdk_event_peek (void)
{
  GList *tmp_list;

  tmp_list = gdk_event_queue_find_first ();
  
  if (tmp_list)
    return gdk_event_copy (tmp_list->data);
  else
    return NULL;
}

void
gdk_event_put (GdkEvent *event)
{
  GdkEvent *new_event;
  
  g_return_if_fail (event != NULL);
  
  new_event = gdk_event_copy (event);

  gdk_event_queue_append (new_event);
}

/*
 *--------------------------------------------------------------
 * gdk_event_copy
 *
 *   Copy a event structure into new storage.
 *
 * Arguments:
 *   "event" is the event struct to copy.
 *
 * Results:
 *   A new event structure.  Free it with gdk_event_free.
 *
 * Side effects:
 *   The reference count of the window in the event is increased.
 *
 *--------------------------------------------------------------
 */

static GMemChunk *event_chunk = NULL;

static GdkEvent*
gdk_event_new (void)
{
  GdkEventPrivate *new_event;
  
  if (event_chunk == NULL)
    event_chunk = g_mem_chunk_new ("events",
				   sizeof (GdkEventPrivate),
				   4096,
				   G_ALLOC_AND_FREE);
  
  new_event = g_chunk_new (GdkEventPrivate, event_chunk);
  new_event->flags = 0;
  
  return (GdkEvent*) new_event;
}

GdkEvent*
gdk_event_copy (GdkEvent *event)
{
  GdkEvent *new_event;
  
  g_return_val_if_fail (event != NULL, NULL);
  
  new_event = gdk_event_new ();
  
  *new_event = *event;
  gdk_window_ref (new_event->any.window);
  
  switch (event->any.type)
    {
    case GDK_KEY_PRESS:
    case GDK_KEY_RELEASE:
      new_event->key.string = g_strdup (event->key.string);
      break;
      
    case GDK_ENTER_NOTIFY:
    case GDK_LEAVE_NOTIFY:
      if (event->crossing.subwindow != NULL)
	gdk_window_ref (event->crossing.subwindow);
      break;
      
    case GDK_DRAG_ENTER:
    case GDK_DRAG_LEAVE:
    case GDK_DRAG_MOTION:
    case GDK_DRAG_STATUS:
    case GDK_DROP_START:
    case GDK_DROP_FINISHED:
      gdk_drag_context_ref (event->dnd.context);
      break;
      
    default:
      break;
    }
  
  return new_event;
}

/*
 *--------------------------------------------------------------
 * gdk_event_free
 *
 *   Free a event structure obtained from gdk_event_copy.  Do not use
 *   with other event structures.
 *
 * Arguments:
 *   "event" is the event struct to free.
 *
 * Results:
 *
 * Side effects:
 *   The reference count of the window in the event is decreased and
 *   might be freed, too.
 *
 *-------------------------------------------------------------- */

void
gdk_event_free (GdkEvent *event)
{
  g_return_if_fail (event != NULL);

  g_assert (event_chunk != NULL); /* paranoid */
  
  if (event->any.window)
    gdk_window_unref (event->any.window);
  
  switch (event->any.type)
    {
    case GDK_KEY_PRESS:
    case GDK_KEY_RELEASE:
      g_free (event->key.string);
      break;
      
    case GDK_ENTER_NOTIFY:
    case GDK_LEAVE_NOTIFY:
      if (event->crossing.subwindow != NULL)
	gdk_window_unref (event->crossing.subwindow);
      break;
      
    case GDK_DRAG_ENTER:
    case GDK_DRAG_LEAVE:
    case GDK_DRAG_MOTION:
    case GDK_DRAG_STATUS:
    case GDK_DROP_START:
    case GDK_DROP_FINISHED:
      gdk_drag_context_unref (event->dnd.context);
      break;
      
    default:
      break;
    }
  
  g_mem_chunk_free (event_chunk, event);
}

/*
 *--------------------------------------------------------------
 * gdk_event_get_time:
 *    Get the timestamp from an event.
 *   arguments:
 *     event:
 *   results:
 *    The event's time stamp, if it has one, otherwise
 *    GDK_CURRENT_TIME.
 *--------------------------------------------------------------
 */

guint32
gdk_event_get_time (GdkEvent *event)
{
  if (event)
    switch (event->type)
      {
      case GDK_MOTION_NOTIFY:
	return event->motion.time;
      case GDK_BUTTON_PRESS:
      case GDK_2BUTTON_PRESS:
      case GDK_3BUTTON_PRESS:
      case GDK_BUTTON_RELEASE:
	return event->button.time;
      case GDK_KEY_PRESS:
      case GDK_KEY_RELEASE:
	return event->key.time;
      case GDK_ENTER_NOTIFY:
      case GDK_LEAVE_NOTIFY:
	return event->crossing.time;
      case GDK_PROPERTY_NOTIFY:
	return event->property.time;
      case GDK_SELECTION_CLEAR:
      case GDK_SELECTION_REQUEST:
      case GDK_SELECTION_NOTIFY:
	return event->selection.time;
      case GDK_PROXIMITY_IN:
      case GDK_PROXIMITY_OUT:
	return event->proximity.time;
      case GDK_DRAG_ENTER:
      case GDK_DRAG_LEAVE:
      case GDK_DRAG_MOTION:
      case GDK_DRAG_STATUS:
      case GDK_DROP_START:
      case GDK_DROP_FINISHED:
	return event->dnd.time;
      default:			/* use current time */
	break;
      }
  
  return GDK_CURRENT_TIME;
}

/*
 *--------------------------------------------------------------
 * gdk_set_show_events
 *
 *   Turns on/off the showing of events.
 *
 * Arguments:
 *   "show_events" is a boolean describing whether or
 *   not to show the events gdk receives.
 *
 * Results:
 *
 * Side effects:
 *   When "show_events" is TRUE, calls to "gdk_event_get"
 *   will output debugging informatin regarding the event
 *   received to stdout.
 *
 *--------------------------------------------------------------
 */

void
gdk_set_show_events (gint show_events)
{
  if (show_events)
    gdk_debug_flags |= GDK_DEBUG_EVENTS;
  else
    gdk_debug_flags &= ~GDK_DEBUG_EVENTS;
}

gint
gdk_get_show_events (void)
{
  return gdk_debug_flags & GDK_DEBUG_EVENTS;
}

static void
gdk_io_destroy (gpointer data)
{
  GdkIOClosure *closure = data;

  if (closure->notify)
    closure->notify (closure->data);

  g_free (closure);
}

/* What do we do with G_IO_NVAL?
 */
#define READ_CONDITION (G_IO_IN | G_IO_HUP | G_IO_ERR)
#define WRITE_CONDITION (G_IO_OUT | G_IO_ERR)
#define EXCEPTION_CONDITION (G_IO_PRI)

static gboolean  
gdk_io_invoke (GIOChannel   *source,
	       GIOCondition  condition,
	       gpointer      data)
{
  GdkIOClosure *closure = data;
  GdkInputCondition gdk_cond = 0;

  if (condition & READ_CONDITION)
    gdk_cond |= GDK_INPUT_READ;
  if (condition & WRITE_CONDITION)
    gdk_cond |= GDK_INPUT_WRITE;
  if (condition & EXCEPTION_CONDITION)
    gdk_cond |= GDK_INPUT_EXCEPTION;

  if (closure->condition & gdk_cond)
    closure->function (closure->data, g_io_channel_unix_get_fd (source), gdk_cond);

  return TRUE;
}

gint
gdk_input_add_full (gint	      source,
		    GdkInputCondition condition,
		    GdkInputFunction  function,
		    gpointer	      data,
		    GdkDestroyNotify  destroy)
{
  guint result;
  GdkIOClosure *closure = g_new (GdkIOClosure, 1);
  GIOChannel *channel;
  GIOCondition cond = 0;

  closure->function = function;
  closure->condition = condition;
  closure->notify = destroy;
  closure->data = data;

  if (condition & GDK_INPUT_READ)
    cond |= READ_CONDITION;
  if (condition & GDK_INPUT_WRITE)
    cond |= WRITE_CONDITION;
  if (condition & GDK_INPUT_EXCEPTION)
    cond |= EXCEPTION_CONDITION;

  channel = g_io_channel_unix_new (source);
  result = g_io_add_watch_full (channel, G_PRIORITY_DEFAULT, cond, 
				gdk_io_invoke,
				closure, gdk_io_destroy);
  g_io_channel_unref (channel);

  return result;
}

gint
gdk_input_add (gint		 source,
	       GdkInputCondition condition,
	       GdkInputFunction	 function,
	       gpointer		 data)
{
  return gdk_input_add_full (source, condition, function, data, NULL);
}

void
gdk_input_remove (gint tag)
{
  g_source_remove (tag);
}

static gint
gdk_event_apply_filters (XEvent *xevent,
			 GdkEvent *event,
			 GList *filters)
{
  GList *tmp_list;
  GdkFilterReturn result;
  
  tmp_list = filters;
  
  while (tmp_list)
    {
      GdkEventFilter *filter = (GdkEventFilter*) tmp_list->data;
      
      tmp_list = tmp_list->next;
      result = filter->function (xevent, event, filter->data);
      if (result !=  GDK_FILTER_CONTINUE)
	return result;
    }
  
  return GDK_FILTER_CONTINUE;
}

void 
gdk_add_client_message_filter (GdkAtom       message_type,
			       GdkFilterFunc func,
			       gpointer      data)
{
  GdkClientFilter *filter = g_new (GdkClientFilter, 1);

  filter->type = message_type;
  filter->function = func;
  filter->data = data;
  
  client_filters = g_list_prepend (client_filters, filter);
}

static gint
gdk_event_translate (GdkEvent *event,
		     XEvent   *xevent)
{
  
  GdkWindow *window;
  GdkWindowPrivate *window_private;
  static XComposeStatus compose;
  KeySym keysym;
  int charcount;
#ifdef USE_XIM
  static gchar* buf = NULL;
  static gint buf_len= 0;
#else
  char buf[16];
#endif
  gint return_val;
  
  return_val = FALSE;
  
  /* Find the GdkWindow that this event occurred in.
   * 
   * We handle events with window=None
   *  specially - they are generated by XFree86's XInput under
   *  some circumstances.
   */
  
  if ((xevent->xany.window == None) &&
      gdk_input_vtable.window_none_event)
    {
      return_val = gdk_input_vtable.window_none_event (event,xevent);
      
      if (return_val >= 0)	/* was handled */
	return return_val;
      else
	return_val = FALSE;
    }
  
  window = gdk_window_lookup (xevent->xany.window);
  window_private = (GdkWindowPrivate *) window;
  
  if (window != NULL)
    gdk_window_ref (window);
  
  event->any.window = window;
  event->any.send_event = xevent->xany.send_event ? TRUE : FALSE;
  
  if (window_private && window_private->destroyed)
    {
      if (xevent->type != DestroyNotify)
	return FALSE;
    }
  else
    {
      /* Check for filters for this window
       */
      GdkFilterReturn result;
      result = gdk_event_apply_filters (xevent, event,
					window_private
					?window_private->filters
					:gdk_default_filters);
      
      if (result != GDK_FILTER_CONTINUE)
	{
	  return (result == GDK_FILTER_TRANSLATE) ? TRUE : FALSE;
	}
    }

#ifdef USE_XIM
  if (window == NULL && gdk_xim_window && xevent->type == KeyPress &&
      !((GdkWindowPrivate *) gdk_xim_window)->destroyed)
    {
      /*
       * If user presses a key in Preedit or Status window, keypress event
       * is sometimes sent to these windows. These windows are not managed
       * by GDK, so we redirect KeyPress event to xim_window.
       *
       * If someone want to use the window whitch is not managed by GDK
       * and want to get KeyPress event, he/she must register the filter
       * function to gdk_default_filters to intercept the event.
       */

      GdkFilterReturn result;

      window = gdk_xim_window;
      window_private = (GdkWindowPrivate *) window;
      gdk_window_ref (window);
      event->any.window = window;

      GDK_NOTE (XIM,
	g_message ("KeyPress event is redirected to xim_window: %#lx",
	  	   xevent->xany.window));

      result = gdk_event_apply_filters (xevent, event,
	  				window_private->filters);
      if (result != GDK_FILTER_CONTINUE)
	return (result == GDK_FILTER_TRANSLATE) ? TRUE : FALSE;
    }
#endif

  /* We do a "manual" conversion of the XEvent to a
   *  GdkEvent. The structures are mostly the same so
   *  the conversion is fairly straightforward. We also
   *  optionally print debugging info regarding events
   *  received.
   */

  return_val = TRUE;

  switch (xevent->type)
    {
    case KeyPress:
      /* Lookup the string corresponding to the given keysym.
       */
      
#ifdef USE_XIM
      if (buf_len == 0) 
	{
	  buf_len = 128;
	  buf = g_new (gchar, buf_len);
	}
      keysym = GDK_VoidSymbol;
      
      if (gdk_xim_ic && gdk_xim_ic->xic)
	{
	  Status status;
	  
	  /* Clear keyval. Depending on status, may not be set */
	  charcount = XmbLookupString(gdk_xim_ic->xic,
				      &xevent->xkey, buf, buf_len-1,
				      &keysym, &status);
	  if (status == XBufferOverflow)
	    {			  /* retry */
	      /* alloc adequate size of buffer */
	      GDK_NOTE (XIM,
			g_message("XIM: overflow (required %i)", charcount));
	      
	      while (buf_len <= charcount)
		buf_len *= 2;
	      buf = (gchar *) g_realloc (buf, buf_len);
	      
	      charcount = XmbLookupString (gdk_xim_ic->xic,
					   &xevent->xkey, buf, buf_len-1,
					   &keysym, &status);
	    }
	  if (status == XLookupNone)
	    {
	      return_val = FALSE;
	      break;
	    }
	}
      else
	charcount = XLookupString (&xevent->xkey, buf, buf_len,
				   &keysym, &compose);
#else
      charcount = XLookupString (&xevent->xkey, buf, 16,
				 &keysym, &compose);
#endif
      event->key.keyval = keysym;
      
      if (charcount > 0 && buf[charcount-1] == '\0')
	charcount --;
      else
	buf[charcount] = '\0';
      
      /* Print debugging info. */
      
#ifdef G_ENABLE_DEBUG
      if (gdk_debug_flags & GDK_DEBUG_EVENTS)
	{
	  g_message ("key press:\twindow: %ld  key: %12s  %d",
		     xevent->xkey.window,
		     event->key.keyval ? XKeysymToString (event->key.keyval) : "(none)",