gtk2/gtk/gtkaccelgroup.c

/* GTK - The GIMP Toolkit
 * Copyright (C) 1998, 2001 Tim Janik
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library. If not, see <http://www.gnu.org/licenses/>.
 */

/*
 * Modified by the GTK+ Team and others 1997-2000.  See the AUTHORS
 * file for a list of people on the GTK+ Team.  See the ChangeLog
 * files for a list of changes.  These files are distributed with
 * GTK+ at ftp://ftp.gtk.org/pub/gtk/.
 */

#include "config.h"
#include <string.h>
#include <stdlib.h>

#include "gtkaccelgroup.h"
#include "gtkaccelgroupprivate.h"
#include "gtkaccellabelprivate.h"
#include "gtkintl.h"
#include "gtkmarshalers.h"
#include "gtkprivate.h"

/**
 * SECTION:gtkaccelgroup
 * @Short_description: Groups of global keyboard accelerators for an
 *     entire GtkWindow
 * @Title: Accelerator Groups
 * @See_also: gtk_window_add_accel_group(), gtk_accel_map_change_entry(),
 * gtk_label_new_with_mnemonic()
 *
 * A #GtkAccelGroup represents a group of keyboard accelerators,
 * typically attached to a toplevel #GtkWindow (with
 * gtk_window_add_accel_group()).
 *
 * Note that “accelerators” are different from
 * “mnemonics”. Accelerators are shortcuts for
 * activating a menu item; they appear alongside the menu item they’re a
 * shortcut for. For example “Ctrl+Q” might appear alongside the “Quit”
 * menu item. Mnemonics are shortcuts for GUI elements such as text
 * entries or buttons; they appear as underlined characters. See
 * gtk_label_new_with_mnemonic(). Menu items can have both accelerators
 * and mnemonics, of course.
 */

/* --- prototypes --- */
static void gtk_accel_group_finalize     (GObject    *object);
static void accel_closure_invalidate     (gpointer    data,
                                          GClosure   *closure);


/* --- variables --- */
static guint  signal_accel_activate      = 0;
static guint  signal_accel_changed       = 0;
static guint  quark_acceleratable_groups = 0;
static guint  default_accel_mod_mask     = 0;

G_DEFINE_TYPE_WITH_PRIVATE (GtkAccelGroup, gtk_accel_group, G_TYPE_OBJECT)


/* --- functions --- */
static void
gtk_accel_group_class_init (GtkAccelGroupClass *class)
{
  GObjectClass *object_class = G_OBJECT_CLASS (class);

  quark_acceleratable_groups = g_quark_from_static_string ("gtk-acceleratable-accel-groups");

  object_class->finalize = gtk_accel_group_finalize;

  class->accel_changed = NULL;

  /**
   * GtkAccelGroup::accel-activate:
   * @accel_group: the #GtkAccelGroup which received the signal
   * @acceleratable: the object on which the accelerator was activated
   * @keyval: the accelerator keyval
   * @modifier: the modifier combination of the accelerator
   *
   * The accel-activate signal is an implementation detail of
   * #GtkAccelGroup and not meant to be used by applications.
   *
   * Returns: %TRUE if the accelerator was activated
   */
  signal_accel_activate =
    g_signal_new (I_("accel-activate"),
                  G_OBJECT_CLASS_TYPE (class),
                  G_SIGNAL_DETAILED,
                  0,
                  _gtk_boolean_handled_accumulator, NULL,
                  _gtk_marshal_BOOLEAN__OBJECT_UINT_FLAGS,
                  G_TYPE_BOOLEAN, 3,
                  G_TYPE_OBJECT,
                  G_TYPE_UINT,
                  GDK_TYPE_MODIFIER_TYPE);
  /**
   * GtkAccelGroup::accel-changed:
   * @accel_group: the #GtkAccelGroup which received the signal
   * @keyval: the accelerator keyval
   * @modifier: the modifier combination of the accelerator
   * @accel_closure: the #GClosure of the accelerator
   *
   * The accel-changed signal is emitted when an entry
   * is added to or removed from the accel group.
   *
   * Widgets like #GtkAccelLabel which display an associated
   * accelerator should connect to this signal, and rebuild
   * their visual representation if the @accel_closure is theirs.
   */
  signal_accel_changed =
    g_signal_new (I_("accel-changed"),
                  G_OBJECT_CLASS_TYPE (class),
                  G_SIGNAL_RUN_FIRST | G_SIGNAL_DETAILED,
                  G_STRUCT_OFFSET (GtkAccelGroupClass, accel_changed),
                  NULL, NULL,
                  _gtk_marshal_VOID__UINT_FLAGS_BOXED,
                  G_TYPE_NONE, 3,
                  G_TYPE_UINT,
                  GDK_TYPE_MODIFIER_TYPE,
                  G_TYPE_CLOSURE);
}

static void
gtk_accel_group_finalize (GObject *object)
{
  GtkAccelGroup *accel_group = GTK_ACCEL_GROUP (object);
  guint i;

  for (i = 0; i < accel_group->priv->n_accels; i++)
    {
      GtkAccelGroupEntry *entry = &accel_group->priv->priv_accels[i];

      g_closure_remove_invalidate_notifier (entry->closure, accel_group, accel_closure_invalidate);

      /* remove quick_accel_add() refcount */
      g_closure_unref (entry->closure);
    }

  g_free (accel_group->priv->priv_accels);

  G_OBJECT_CLASS (gtk_accel_group_parent_class)->finalize (object);
}

static void
gtk_accel_group_init (GtkAccelGroup *accel_group)
{
  GtkAccelGroupPrivate *priv;

  accel_group->priv = gtk_accel_group_get_instance_private (accel_group);
  priv = accel_group->priv;

  priv->acceleratables = NULL;
  priv->n_accels = 0;
  priv->priv_accels = NULL;
}

/**
 * gtk_accel_group_new:
 *
 * Creates a new #GtkAccelGroup.
 *
 * Returns: a new #GtkAccelGroup object
 */
GtkAccelGroup*
gtk_accel_group_new (void)
{
  return g_object_new (GTK_TYPE_ACCEL_GROUP, NULL);
}

static void
accel_group_weak_ref_detach (GSList  *free_list,
                             GObject *stale_object)
{
  GSList *slist;

  for (slist = free_list; slist; slist = slist->next)
    {
      GtkAccelGroup *accel_group;

      accel_group = slist->data;
      accel_group->priv->acceleratables = g_slist_remove (accel_group->priv->acceleratables, stale_object);
      g_object_unref (accel_group);
    }
  g_slist_free (free_list);
  g_object_set_qdata (stale_object, quark_acceleratable_groups, NULL);
}

void
_gtk_accel_group_attach (GtkAccelGroup *accel_group,
                         GObject       *object)
{
  GSList *slist;

  g_return_if_fail (GTK_IS_ACCEL_GROUP (accel_group));
  g_return_if_fail (G_IS_OBJECT (object));
  g_return_if_fail (g_slist_find (accel_group->priv->acceleratables, object) == NULL);

  g_object_ref (accel_group);
  accel_group->priv->acceleratables = g_slist_prepend (accel_group->priv->acceleratables, object);
  slist = g_object_get_qdata (object, quark_acceleratable_groups);
  if (slist)
    g_object_weak_unref (object,
                         (GWeakNotify) accel_group_weak_ref_detach,
                         slist);
  slist = g_slist_prepend (slist, accel_group);
  g_object_set_qdata (object, quark_acceleratable_groups, slist);
  g_object_weak_ref (object,
                     (GWeakNotify) accel_group_weak_ref_detach,
                     slist);
}

void
_gtk_accel_group_detach (GtkAccelGroup *accel_group,
                         GObject       *object)
{
  GSList *slist;

  g_return_if_fail (GTK_IS_ACCEL_GROUP (accel_group));
  g_return_if_fail (G_IS_OBJECT (object));
  g_return_if_fail (g_slist_find (accel_group->priv->acceleratables, object) != NULL);

  accel_group->priv->acceleratables = g_slist_remove (accel_group->priv->acceleratables, object);
  slist = g_object_get_qdata (object, quark_acceleratable_groups);
  g_object_weak_unref (object,
                       (GWeakNotify) accel_group_weak_ref_detach,
                       slist);
  slist = g_slist_remove (slist, accel_group);
  g_object_set_qdata (object, quark_acceleratable_groups, slist);
  if (slist)
    g_object_weak_ref (object,
                       (GWeakNotify) accel_group_weak_ref_detach,
                       slist);
  g_object_unref (accel_group);
}

/**
 * gtk_accel_groups_from_object:
 * @object: a #GObject, usually a #GtkWindow
 *
 * Gets a list of all accel groups which are attached to @object.
 *
 * Returns: (element-type GtkAccelGroup) (transfer none): a list of
 *     all accel groups which are attached to @object
 */
GSList*
gtk_accel_groups_from_object (GObject *object)
{
  g_return_val_if_fail (G_IS_OBJECT (object), NULL);

  return g_object_get_qdata (object, quark_acceleratable_groups);
}

/**
 * gtk_accel_group_find:
 * @accel_group: a #GtkAccelGroup
 * @find_func: (scope call): a function to filter the entries
 *    of @accel_group with
 * @data: data to pass to @find_func
 *
 * Finds the first entry in an accelerator group for which
 * @find_func returns %TRUE and returns its #GtkAccelKey.
 *
 * Returns: (transfer none): the key of the first entry passing
 *    @find_func. The key is owned by GTK+ and must not be freed.
 */
GtkAccelKey*
gtk_accel_group_find (GtkAccelGroup         *accel_group,
                      GtkAccelGroupFindFunc  find_func,
                      gpointer               data)
{
  GtkAccelKey *key = NULL;
  guint i;

  g_return_val_if_fail (GTK_IS_ACCEL_GROUP (accel_group), NULL);
  g_return_val_if_fail (find_func != NULL, NULL);

  g_object_ref (accel_group);
  for (i = 0; i < accel_group->priv->n_accels; i++)
    if (find_func (&accel_group->priv->priv_accels[i].key,
                   accel_group->priv->priv_accels[i].closure,
                   data))
      {
        key = &accel_group->priv->priv_accels[i].key;
        break;
      }
  g_object_unref (accel_group);

  return key;
}

static void
accel_closure_invalidate (gpointer  data,
                          GClosure *closure)
{
  GtkAccelGroup *accel_group = GTK_ACCEL_GROUP (data);

  gtk_accel_group_disconnect (accel_group, closure);
}

static int
bsearch_compare_accels (const void *d1,
                        const void *d2)
{
  const GtkAccelGroupEntry *entry1 = d1;
  const GtkAccelGroupEntry *entry2 = d2;

  if (entry1->key.accel_key == entry2->key.accel_key)
    return entry1->key.accel_mods < entry2->key.accel_mods ? -1 : entry1->key.accel_mods > entry2->key.accel_mods;
  else
    return entry1->key.accel_key < entry2->key.accel_key ? -1 : 1;
}

static void
quick_accel_add (GtkAccelGroup   *accel_group,
                 guint            accel_key,
                 GdkModifierType  accel_mods,
                 GtkAccelFlags    accel_flags,
                 GClosure        *closure)
{
  guint pos, i = accel_group->priv->n_accels++;
  GtkAccelGroupEntry key;

  /* find position */
  key.key.accel_key = accel_key;
  key.key.accel_mods = accel_mods;
  for (pos = 0; pos < i; pos++)
    if (bsearch_compare_accels (&key, accel_group->priv->priv_accels + pos) < 0)
      break;

  /* insert at position, ref closure */
  accel_group->priv->priv_accels = g_renew (GtkAccelGroupEntry, accel_group->priv->priv_accels, accel_group->priv->n_accels);
  memmove (accel_group->priv->priv_accels + pos + 1, accel_group->priv->priv_accels + pos,
           (i - pos) * sizeof (accel_group->priv->priv_accels[0]));
  accel_group->priv->priv_accels[pos].key.accel_key = accel_key;
  accel_group->priv->priv_accels[pos].key.accel_mods = accel_mods;
  accel_group->priv->priv_accels[pos].key.accel_flags = accel_flags;
  accel_group->priv->priv_accels[pos].closure = g_closure_ref (closure);
  g_closure_sink (closure);

  /* handle closure invalidation and reverse lookups */
  g_closure_add_invalidate_notifier (closure, accel_group, accel_closure_invalidate);

  /* connect and notify changed */
  if (accel_key)
    {
      gchar *accel_name = gtk_accelerator_name (accel_key, accel_mods);
      GQuark accel_quark = g_quark_from_string (accel_name);

      g_free (accel_name);

      /* setup handler */
      g_signal_connect_closure_by_id (accel_group, signal_accel_activate, accel_quark, closure, FALSE);

      /* and notify */
      g_signal_emit (accel_group, signal_accel_changed, accel_quark, accel_key, accel_mods, closure);
    }
}

static void
quick_accel_remove (GtkAccelGroup *accel_group,
                    guint          pos)
{
  GQuark accel_quark = 0;
  GtkAccelGroupEntry *entry = accel_group->priv->priv_accels + pos;
  guint accel_key = entry->key.accel_key;
  GdkModifierType accel_mods = entry->key.accel_mods;
  GClosure *closure = entry->closure;

  /* quark for notification */
  if (accel_key)
    {
      gchar *accel_name = gtk_accelerator_name (accel_key, accel_mods);

      accel_quark = g_quark_from_string (accel_name);
      g_free (accel_name);
    }

  /* clean up closure invalidate notification and disconnect */
  g_closure_remove_invalidate_notifier (entry->closure, accel_group, accel_closure_invalidate);
  if (accel_quark)
    g_signal_handlers_disconnect_matched (accel_group,
                                          G_SIGNAL_MATCH_ID | G_SIGNAL_MATCH_DETAIL | G_SIGNAL_MATCH_CLOSURE,
                                          signal_accel_activate, accel_quark,
                                          closure, NULL, NULL);

  /* physically remove */
  accel_group->priv->n_accels -= 1;
  memmove (entry, entry + 1,
           (accel_group->priv->n_accels - pos) * sizeof (accel_group->priv->priv_accels[0]));

  /* and notify */
  if (accel_quark)
    g_signal_emit (accel_group, signal_accel_changed, accel_quark, accel_key, accel_mods, closure);

  /* remove quick_accel_add() refcount */
  g_closure_unref (closure);
}

static GtkAccelGroupEntry*
quick_accel_find (GtkAccelGroup   *accel_group,
                  guint            accel_key,
                  GdkModifierType  accel_mods,
                  guint           *count_p)
{
  GtkAccelGroupEntry *entry;
  GtkAccelGroupEntry key;

  *count_p = 0;

  if (!accel_group->priv->n_accels)
    return NULL;

  key.key.accel_key = accel_key;
  key.key.accel_mods = accel_mods;
  entry = bsearch (&key, accel_group->priv->priv_accels, accel_group->priv->n_accels,
                   sizeof (accel_group->priv->priv_accels[0]), bsearch_compare_accels);

  if (!entry)
    return NULL;

  /* step back to the first member */
  for (; entry > accel_group->priv->priv_accels; entry--)
    if (entry[-1].key.accel_key != accel_key ||
        entry[-1].key.accel_mods != accel_mods)
      break;
  /* count equal members */
  for (; entry + *count_p < accel_group->priv->priv_accels + accel_group->priv->n_accels; (*count_p)++)
    if (entry[*count_p].key.accel_key != accel_key ||
        entry[*count_p].key.accel_mods != accel_mods)
      break;
  return entry;
}

/**
 * gtk_accel_group_connect:
 * @accel_group: the accelerator group to install an accelerator in
 * @accel_key: key value of the accelerator
 * @accel_mods: modifier combination of the accelerator
 * @accel_flags: a flag mask to configure this accelerator
 * @closure: closure to be executed upon accelerator activation
 *
 * Installs an accelerator in this group. When @accel_group is being
 * activated in response to a call to gtk_accel_groups_activate(),
 * @closure will be invoked if the @accel_key and @accel_mods from
 * gtk_accel_groups_activate() match those of this connection.
 *
 * The signature used for the @closure is that of #GtkAccelGroupActivate.
 *
 * Note that, due to implementation details, a single closure can
 * only be connected to one accelerator group.
 */
void
gtk_accel_group_connect (GtkAccelGroup   *accel_group,
                         guint            accel_key,
                         GdkModifierType  accel_mods,
                         GtkAccelFlags    accel_flags,
                         GClosure        *closure)
{
  g_return_if_fail (GTK_IS_ACCEL_GROUP (accel_group));
  g_return_if_fail (closure != NULL);
  g_return_if_fail (accel_key > 0);
  g_return_if_fail (gtk_accel_group_from_accel_closure (closure) == NULL);

  g_object_ref (accel_group);
  if (!closure->is_invalid)
    quick_accel_add (accel_group,
                     gdk_keyval_to_lower (accel_key),
                     accel_mods, accel_flags, closure);
  g_object_unref (accel_group);
}

/**
 * gtk_accel_group_disconnect:
 * @accel_group: the accelerator group to remove an accelerator from
 * @closure: (allow-none): the closure to remove from this accelerator
 *     group, or %NULL to remove all closures
 *
 * Removes an accelerator previously installed through
 * gtk_accel_group_connect().
 *
 * Returns: %TRUE if the closure was found and got disconnected
 */
gboolean
gtk_accel_group_disconnect (GtkAccelGroup *accel_group,
                            GClosure      *closure)
{
  guint i;

  g_return_val_if_fail (GTK_IS_ACCEL_GROUP (accel_group), FALSE);

  for (i = 0; i < accel_group->priv->n_accels; i++)
    if (accel_group->priv->priv_accels[i].closure == closure)
      {
        g_object_ref (accel_group);
        quick_accel_remove (accel_group, i);
        g_object_unref (accel_group);
        return TRUE;
      }
  return FALSE;
}

/**
 * gtk_accel_group_disconnect_key:
 * @accel_group: the accelerator group to install an accelerator in
 * @accel_key: key value of the accelerator
 * @accel_mods: modifier combination of the accelerator
 *
 * Removes an accelerator previously installed through
 * gtk_accel_group_connect().
 *
 * Returns: %TRUE if there was an accelerator which could be
 *     removed, %FALSE otherwise
 */
gboolean
gtk_accel_group_disconnect_key (GtkAccelGroup   *accel_group,
                                guint            accel_key,
                                GdkModifierType  accel_mods)
{
  GtkAccelGroupEntry *entries;
  GSList *slist, *clist = NULL;
  gboolean removed_one = FALSE;
  guint n;

  g_return_val_if_fail (GTK_IS_ACCEL_GROUP (accel_group), FALSE);

  g_object_ref (accel_group);

  accel_key = gdk_keyval_to_lower (accel_key);
  entries = quick_accel_find (accel_group, accel_key, accel_mods, &n);
  while (n--)
    {
      GClosure *closure = g_closure_ref (entries[n].closure);

      clist = g_slist_prepend (clist, closure);
    }

  for (slist = clist; slist; slist = slist->next)
    {
      GClosure *closure = slist->data;

      removed_one |= gtk_accel_group_disconnect (accel_group, closure);
      g_closure_unref (closure);
    }
  g_slist_free (clist);

  g_object_unref (accel_group);

  return removed_one;
}

GSList*
_gtk_accel_group_get_accelerables (GtkAccelGroup *accel_group)
{
    g_return_val_if_fail (GTK_IS_ACCEL_GROUP (accel_group), NULL);

    return accel_group->priv->acceleratables;
}

/**
 * gtk_accel_group_query:
 * @accel_group: the accelerator group to query
 * @accel_key: key value of the accelerator
 * @accel_mods: modifier combination of the accelerator
 * @n_entries: (out) (optional): location to return the number
 *     of entries found, or %NULL
 *
 * Queries an accelerator group for all entries matching @accel_key
 * and @accel_mods.
 *
 * Returns: (nullable) (transfer none) (array length=n_entries): an array of
 *     @n_entries #GtkAccelGroupEntry elements, or %NULL. The array
 *     is owned by GTK+ and must not be freed.
 */
GtkAccelGroupEntry*
gtk_accel_group_query (GtkAccelGroup   *accel_group,
                       guint            accel_key,
                       GdkModifierType  accel_mods,
                       guint           *n_entries)
{
  GtkAccelGroupEntry *entries;
  guint n;

  g_return_val_if_fail (GTK_IS_ACCEL_GROUP (accel_group), NULL);

  entries = quick_accel_find (accel_group, gdk_keyval_to_lower (accel_key), accel_mods, &n);

  if (n_entries)
    *n_entries = entries ? n : 0;

  return entries;
}

/**
 * gtk_accel_group_from_accel_closure:
 * @closure: a #GClosure
 *
 * Finds the #GtkAccelGroup to which @closure is connected;
 * see gtk_accel_group_connect().
 *
 * Returns: (nullable) (transfer none): the #GtkAccelGroup to which @closure
 *     is connected, or %NULL
 */
GtkAccelGroup*
gtk_accel_group_from_accel_closure (GClosure *closure)
{
  guint i;

  g_return_val_if_fail (closure != NULL, NULL);

  /* A few remarks on what we do here. in general, we need a way to
   * reverse lookup accel_groups from closures that are being used in
   * accel groups. this could be done e.g via a hashtable. it is however
   * cheaper (memory wise) to just use the invalidation notifier on the
   * closure itself (which we need to install anyway), that contains the
   * accel group as data which, besides needing to peek a bit at closure
   * internals, works just as good.
   */
  for (i = 0; i < G_CLOSURE_N_NOTIFIERS (closure); i++)
    if (closure->notifiers[i].notify == accel_closure_invalidate)
      return closure->notifiers[i].data;

  return NULL;
}

/**
 * gtk_accel_group_activate:
 * @accel_group: a #GtkAccelGroup
 * @accel_quark: the quark for the accelerator name
 * @acceleratable: the #GObject, usually a #GtkWindow, on which
 *    to activate the accelerator
 * @accel_key: accelerator keyval from a key event
 * @accel_mods: keyboard state mask from a key event
 *
 * Finds the first accelerator in @accel_group that matches
 * @accel_key and @accel_mods, and activates it.
 *
 * Returns: %TRUE if an accelerator was activated and handled
 *     this keypress
 */
gboolean
gtk_accel_group_activate (GtkAccelGroup   *accel_group,
                          GQuark           accel_quark,
                          GObject         *acceleratable,
                          guint            accel_key,
                          GdkModifierType  accel_mods)
{
  gboolean was_handled;

  g_return_val_if_fail (GTK_IS_ACCEL_GROUP (accel_group), FALSE);
  g_return_val_if_fail (G_IS_OBJECT (acceleratable), FALSE);

  was_handled = FALSE;
  g_signal_emit (accel_group, signal_accel_activate, accel_quark,
                 acceleratable, accel_key, accel_mods, &was_handled);

  return was_handled;
}

/**
 * gtk_accel_groups_activate:
 * @object: the #GObject, usually a #GtkWindow, on which
 *     to activate the accelerator
 * @accel_key: accelerator keyval from a key event
 * @accel_mods: keyboard state mask from a key event
 *
 * Finds the first accelerator in any #GtkAccelGroup attached
 * to @object that matches @accel_key and @accel_mods, and
 * activates that accelerator.
 *
 * Returns: %TRUE if an accelerator was activated and handled
 *     this keypress
 */
gboolean
gtk_accel_groups_activate (GObject         *object,
                           guint            accel_key,
                           GdkModifierType  accel_mods)
{
  g_return_val_if_fail (G_IS_OBJECT (object), FALSE);

  if (gtk_accelerator_valid (accel_key, accel_mods))
    {
      gchar *accel_name;
      GQuark accel_quark;
      GSList *slist;

      accel_name = gtk_accelerator_name (accel_key, (accel_mods & gtk_accelerator_get_default_mod_mask ()));
      accel_quark = g_quark_from_string (accel_name);
      g_free (accel_name);

      for (slist = gtk_accel_groups_from_object (object); slist; slist = slist->next)
        if (gtk_accel_group_activate (slist->data, accel_quark, object, accel_key, accel_mods))
          return TRUE;
    }

  return FALSE;
}

/**
 * gtk_accelerator_valid:
 * @keyval: a GDK keyval
 * @modifiers: modifier mask
 *
 * Determines whether a given keyval and modifier mask constitute
 * a valid keyboard accelerator. For example, the #GDK_KEY_a keyval
 * plus #GDK_CONTROL_MASK is valid - this is a “Ctrl+a” accelerator.
 * But, you can't, for instance, use the #GDK_KEY_Control_L keyval
 * as an accelerator.
 *
 * Returns: %TRUE if the accelerator is valid
 */
gboolean
gtk_accelerator_valid (guint           keyval,
                       GdkModifierType modifiers)
{
  static const guint invalid_accelerator_vals[] = {
    GDK_KEY_Shift_L, GDK_KEY_Shift_R, GDK_KEY_Shift_Lock,
    GDK_KEY_Caps_Lock, GDK_KEY_ISO_Lock, GDK_KEY_Control_L,
    GDK_KEY_Control_R, GDK_KEY_Meta_L, GDK_KEY_Meta_R,
    GDK_KEY_Alt_L, GDK_KEY_Alt_R, GDK_KEY_Super_L, GDK_KEY_Super_R,
    GDK_KEY_Hyper_L, GDK_KEY_Hyper_R, GDK_KEY_ISO_Level3_Shift,
    GDK_KEY_ISO_Next_Group, GDK_KEY_ISO_Prev_Group,
    GDK_KEY_ISO_First_Group, GDK_KEY_ISO_Last_Group,
    GDK_KEY_Mode_switch, GDK_KEY_Num_Lock, GDK_KEY_Multi_key,
    GDK_KEY_Scroll_Lock, GDK_KEY_Sys_Req,
    GDK_KEY_Tab, GDK_KEY_ISO_Left_Tab, GDK_KEY_KP_Tab,
    GDK_KEY_First_Virtual_Screen, GDK_KEY_Prev_Virtual_Screen,
    GDK_KEY_Next_Virtual_Screen, GDK_KEY_Last_Virtual_Screen,
    GDK_KEY_Terminate_Server, GDK_KEY_AudibleBell_Enable,
    0
  };
  static const guint invalid_unmodified_vals[] = {
    GDK_KEY_Up, GDK_KEY_Down, GDK_KEY_Left, GDK_KEY_Right,
    GDK_KEY_KP_Up, GDK_KEY_KP_Down, GDK_KEY_KP_Left, GDK_KEY_KP_Right,
    0
  };
  const guint *ac_val;

  modifiers &= GDK_MODIFIER_MASK;

  if (keyval <= 0xFF)
    return keyval >= 0x20;

  ac_val = invalid_accelerator_vals;
  while (*ac_val)
    {
      if (keyval == *ac_val++)
        return FALSE;
    }

  if (!modifiers)
    {
      ac_val = invalid_unmodified_vals;
      while (*ac_val)
        {
          if (keyval == *ac_val++)
            return FALSE;
        }
    }

  return TRUE;
}

static inline gboolean
is_alt (const gchar *string)
{
  return ((string[0] == '<') &&
          (string[1] == 'a' || string[1] == 'A') &&
          (string[2] == 'l' || string[2] == 'L') &&
          (string[3] == 't' || string[3] == 'T') &&
          (string[4] == '>'));
}

static inline gboolean
is_ctl (const gchar *string)
{
  return ((string[0] == '<') &&
          (string[1] == 'c' || string[1] == 'C') &&
          (string[2] == 't' || string[2] == 'T') &&
          (string[3] == 'l' || string[3] == 'L') &&
          (string[4] == '>'));
}

static inline gboolean
is_modx (const gchar *string)
{
  return ((string[0] == '<') &&
          (string[1] == 'm' || string[1] == 'M') &&
          (string[2] == 'o' || string[2] == 'O') &&
          (string[3] == 'd' || string[3] == 'D') &&
          (string[4] >= '1' && string[4] <= '5') &&
          (string[5] == '>'));
}

static inline gboolean
is_ctrl (const gchar *string)
{
  return ((string[0] == '<') &&
          (string[1] == 'c' || string[1] == 'C') &&
          (string[2] == 't' || string[2] == 'T') &&
          (string[3] == 'r' || string[3] == 'R') &&
          (string[4] == 'l' || string[4] == 'L') &&
          (string[5] == '>'));
}

static inline gboolean
is_shft (const gchar *string)
{
  return ((string[0] == '<') &&
          (string[1] == 's' || string[1] == 'S') &&
          (string[2] == 'h' || string[2] == 'H') &&
          (string[3] == 'f' || string[3] == 'F') &&
          (string[4] == 't' || string[4] == 'T') &&
          (string[5] == '>'));
}

static inline gboolean
is_shift (const gchar *string)
{
  return ((string[0] == '<') &&
          (string[1] == 's' || string[1] == 'S') &&
          (string[2] == 'h' || string[2] == 'H') &&
          (string[3] == 'i' || string[3] == 'I') &&
          (string[4] == 'f' || string[4] == 'F') &&
          (string[5] == 't' || string[5] == 'T') &&
          (string[6] == '>'));
}

static inline gboolean
is_control (const gchar *string)
{
  return ((string[0] == '<') &&
          (string[1] == 'c' || string[1] == 'C') &&
          (string[2] == 'o' || string[2] == 'O') &&
          (string[3] == 'n' || string[3] == 'N') &&
          (string[4] == 't' || string[4] == 'T') &&
          (string[5] == 'r' || string[5] == 'R') &&
          (string[6] == 'o' || string[6] == 'O') &&
          (string[7] == 'l' || string[7] == 'L') &&
          (string[8] == '>'));
}

static inline gboolean
is_meta (const gchar *string)
{
  return ((string[0] == '<') &&
          (string[1] == 'm' || string[1] == 'M') &&
          (string[2] == 'e' || string[2] == 'E') &&
          (string[3] == 't' || string[3] == 'T') &&
          (string[4] == 'a' || string[4] == 'A') &&
          (string[5] == '>'));
}

static inline gboolean
is_super (const gchar *string)
{
  return ((string[0] == '<') &&
          (string[1] == 's' || string[1] == 'S') &&
          (string[2] == 'u' || string[2] == 'U') &&
          (string[3] == 'p' || string[3] == 'P') &&
          (string[4] == 'e' || string[4] == 'E') &&
          (string[5] == 'r' || string[5] == 'R') &&
          (string[6] == '>'));
}

static inline gboolean
is_hyper (const gchar *string)
{
  return ((string[0] == '<') &&
          (string[1] == 'h' || string[1] == 'H') &&
          (string[2] == 'y' || string[2] == 'Y') &&
          (string[3] == 'p' || string[3] == 'P') &&
          (string[4] == 'e' || string[4] == 'E') &&
          (string[5] == 'r' || string[5] == 'R') &&
          (string[6] == '>'));
}

static inline gboolean
is_primary (const gchar *string)
{
  return ((string[0] == '<') &&
	  (string[1] == 'p' || string[1] == 'P') &&
	  (string[2] == 'r' || string[2] == 'R') &&
	  (string[3] == 'i' || string[3] == 'I') &&
	  (string[4] == 'm' || string[4] == 'M') &&
	  (string[5] == 'a' || string[5] == 'A') &&
	  (string[6] == 'r' || string[6] == 'R') &&
	  (string[7] == 'y' || string[7] == 'Y') &&
	  (string[8] == '>'));
}

static inline gboolean
is_keycode (const gchar *string)
{
  return (string[0] == '0' &&
          string[1] == 'x' &&
          g_ascii_isxdigit (string[2]) &&
          g_ascii_isxdigit (string[3]));
}

/**
 * gtk_accelerator_parse_with_keycode:
 * @accelerator: string representing an accelerator
 * @accelerator_key: (out) (allow-none): return location for accelerator
 *     keyval, or %NULL
 * @accelerator_codes: (out) (array zero-terminated=1) (transfer full) (allow-none):
 *     return location for accelerator keycodes, or %NULL
 * @accelerator_mods: (out) (allow-none): return location for accelerator
 *     modifier mask, %NULL
 *
 * Parses a string representing an accelerator, similarly to
 * gtk_accelerator_parse() but handles keycodes as well. This is only
 * useful for system-level components, applications should use
 * gtk_accelerator_parse() instead.
 *
 * If @accelerator_codes is given and the result stored in it is non-%NULL,
 * the result must be freed with g_free().
 *
 * If a keycode is present in the accelerator and no @accelerator_codes
 * is given, the parse will fail.
 *
 * If the parse fails, @accelerator_key, @accelerator_mods and
 * @accelerator_codes will be set to 0 (zero).
 *
 * Returns: %TRUE if parsing succeeded
 */
gboolean
gtk_accelerator_parse_with_keycode (const gchar     *accelerator,
                                    guint           *accelerator_key,
                                    guint          **accelerator_codes,
                                    GdkModifierType *accelerator_mods)
{
  guint keyval;
  GdkModifierType mods;
  gint len;
  gboolean error;

  if (accelerator_key)
    *accelerator_key = 0;
  if (accelerator_mods)
    *accelerator_mods = 0;
  if (accelerator_codes)
    *accelerator_codes = NULL;

  g_return_val_if_fail (accelerator != NULL, FALSE);

  error = FALSE;
  keyval = 0;
  mods = 0;
  len = strlen (accelerator);
  while (len)
    {
      if (*accelerator == '<')
        {
          if (len >= 9 && is_primary (accelerator))
            {
              accelerator += 9;
              len -= 9;
              mods |= _gtk_get_primary_accel_mod ();
            }
          else if (len >= 9 && is_control (accelerator))
            {
              accelerator += 9;
              len -= 9;
              mods |= GDK_CONTROL_MASK;
            }
          else if (len >= 7 && is_shift (accelerator))
            {
              accelerator += 7;
              len -= 7;
              mods |= GDK_SHIFT_MASK;
            }
          else if (len >= 6 && is_shft (accelerator))
            {
              accelerator += 6;
              len -= 6;
              mods |= GDK_SHIFT_MASK;
            }
          else if (len >= 6 && is_ctrl (accelerator))
            {
              accelerator += 6;
              len -= 6;
              mods |= GDK_CONTROL_MASK;
            }
          else if (len >= 6 && is_modx (accelerator))
            {
              static const guint mod_vals[] = {
                GDK_MOD1_MASK, GDK_MOD2_MASK, GDK_MOD3_MASK,
                GDK_MOD4_MASK, GDK_MOD5_MASK
              };

              len -= 6;
              accelerator += 4;
              mods |= mod_vals[*accelerator - '1'];
              accelerator += 2;
            }
          else if (len >= 5 && is_ctl (accelerator))
            {
              accelerator += 5;
              len -= 5;
              mods |= GDK_CONTROL_MASK;
            }
          else if (len >= 5 && is_alt (accelerator))
            {
              accelerator += 5;
              len -= 5;
              mods |= GDK_MOD1_MASK;
            }
          else if (len >= 6 && is_meta (accelerator))
            {
              accelerator += 6;
              len -= 6;
              mods |= GDK_META_MASK;
            }
          else if (len >= 7 && is_hyper (accelerator))
            {
              accelerator += 7;
              len -= 7;
              mods |= GDK_HYPER_MASK;
            }
          else if (len >= 7 && is_super (accelerator))
            {
              accelerator += 7;
              len -= 7;
              mods |= GDK_SUPER_MASK;
            }
          else
            {
              gchar last_ch;

              last_ch = *accelerator;
              while (last_ch && last_ch != '>')
                {
                  accelerator += 1;
                  len -= 1;
                  last_ch = *accelerator;
                }
            }
        }
      else
        {
          if (len >= 4 && is_keycode (accelerator))
            {
               char keystring[5];
               gchar *endptr;
               gint tmp_keycode;

               memcpy (keystring, accelerator, 4);
               keystring [4] = '\000';

               tmp_keycode = strtol (keystring, &endptr, 16);

               if (endptr == NULL || *endptr != '\000')
                 {
                   error = TRUE;
                   goto out;
                 }
               else if (accelerator_codes != NULL)
                 {
                   /* 0x00 is an invalid keycode too. */
                   if (tmp_keycode == 0)
                     {
                       error = TRUE;
                       goto out;
                     }
                   else
                     {
                       *accelerator_codes = g_new0 (guint, 2);
                       (*accelerator_codes)[0] = tmp_keycode;
                     }
                 }
               else
                 {
                   /* There was a keycode in the string, but
                    * we cannot store it, so we have an error */
                   error = TRUE;
                   goto out;
                 }
            }
	  else
	    {
	      keyval = gdk_keyval_from_name (accelerator);
	      if (keyval == GDK_KEY_VoidSymbol)
	        {
	          error = TRUE;
	          goto out;
		}
	    }

          if (keyval && accelerator_codes != NULL)
            {
              GdkKeymap *keymap = gdk_display_get_keymap (gdk_display_get_default ());
              GdkKeymapKey *keys;
              gint n_keys, i, j;

              if (!gdk_keymap_get_entries_for_keyval (keymap, keyval, &keys, &n_keys))
                {
                  /* Not in keymap */
                  error = TRUE;
                  goto out;
                }
              else
                {
                  *accelerator_codes = g_new0 (guint, n_keys + 1);

                  /* Prefer level-0 group-0 keys to modified keys */
                  for (i = 0, j = 0; i < n_keys; ++i)
                    {
                      if (keys[i].level == 0 && keys[i].group == 0)
                        (*accelerator_codes)[j++] = keys[i].keycode;
                    }

                  /* No level-0 group-0 keys? Find in the whole group-0 */
                  if (j == 0)
                    {
                      for (i = 0, j = 0; i < n_keys; ++i)
                        {
                          if (keys[i].group == 0)
                            (*accelerator_codes)[j++] = keys[i].keycode;
                        }
                    }

                  /* Still nothing? Try in other groups */
                  if (j == 0)
                    {
                      for (i = 0, j = 0; i < n_keys; ++i)
                        (*accelerator_codes)[j++] = keys[i].keycode;
                    }

                  if (j == 0)
                    {
                      g_free (*accelerator_codes);
                      *accelerator_codes = NULL;
                      /* Not in keymap */
                      error = TRUE;
                      goto out;
                    }
                  g_free (keys);
                }
            }

          accelerator += len;
          len -= len;
        }
    }

out:
  if (error)
    keyval = mods = 0;

  if (accelerator_key)
    *accelerator_key = gdk_keyval_to_lower (keyval);
  if (accelerator_mods)
    *accelerator_mods = mods;

  return !error;
}

/**
 * gtk_accelerator_parse:
 * @accelerator: string representing an accelerator
 * @accelerator_key: (out) (allow-none): return location for accelerator
 *     keyval, or %NULL
 * @accelerator_mods: (out) (allow-none): return location for accelerator
 *     modifier mask, %NULL
 *
 * Parses a string representing an accelerator. The format looks like
 * “<Control>a” or “<Shift><Alt>F1” or “<Release>z” (the last one is
 * for key release).
 *
 * The parser is fairly liberal and allows lower or upper case, and also
 * abbreviations such as “<Ctl>” and “<Ctrl>”. Key names are parsed using
 * gdk_keyval_from_name(). For character keys the name is not the symbol,
 * but the lowercase name, e.g. one would use “<Ctrl>minus” instead of
 * “<Ctrl>-”.
 *
 * If the parse fails, @accelerator_key and @accelerator_mods will
 * be set to 0 (zero).
 */
gboolean
gtk_accelerator_parse (const gchar     *accelerator,
                       guint           *accelerator_key,
                       GdkModifierType *accelerator_mods)
{
  return gtk_accelerator_parse_with_keycode (accelerator, accelerator_key, NULL, accelerator_mods);
}

/**
 * gtk_accelerator_name_with_keycode:
 * @display: (allow-none): a #GdkDisplay or %NULL to use the default display
 * @accelerator_key: accelerator keyval
 * @keycode: accelerator keycode
 * @accelerator_mods: accelerator modifier mask
 *
 * Converts an accelerator keyval and modifier mask
 * into a string parseable by gtk_accelerator_parse_with_keycode(),
 * similarly to gtk_accelerator_name() but handling keycodes.
 * This is only useful for system-level components, applications
 * should use gtk_accelerator_parse() instead.
 *
 * Returns: a newly allocated accelerator name.
 */
gchar *
gtk_accelerator_name_with_keycode (GdkDisplay      *display,
                                   guint            accelerator_key,
                                   guint            keycode,
                                   GdkModifierType  accelerator_mods)
{
  gchar *gtk_name;

  if (display == NULL)
    display = gdk_display_manager_get_default_display (gdk_display_manager_get ());

  gdk_keymap_add_virtual_modifiers (gdk_display_get_keymap (display), &accelerator_mods);
  gtk_name = gtk_accelerator_name (accelerator_key, accelerator_mods);

  if (!accelerator_key)
    {
      gchar *name;
      name = g_strdup_printf ("%s0x%02x", gtk_name, keycode);
      g_free (gtk_name);
      return name;
    }

  return gtk_name;
}

/**
 * gtk_accelerator_name:
 * @accelerator_key: accelerator keyval
 * @accelerator_mods: accelerator modifier mask
 *
 * Converts an accelerator keyval and modifier mask into a string
 * parseable by gtk_accelerator_parse(). For example, if you pass in
 * #GDK_KEY_q and #GDK_CONTROL_MASK, this function returns “<Control>q”.
 *
 * If you need to display accelerators in the user interface,
 * see gtk_accelerator_get_label().
 *
 * Returns: a newly-allocated accelerator name
 */
gchar*
gtk_accelerator_name (guint           accelerator_key,
                      GdkModifierType accelerator_mods)
{
  static const gchar text_primary[] = "<Primary>";
  static const gchar text_shift[] = "<Shift>";
  static const gchar text_control[] = "<Control>";
  static const gchar text_mod1[] = "<Alt>";
  static const gchar text_mod2[] = "<Mod2>";
  static const gchar text_mod3[] = "<Mod3>";
  static const gchar text_mod4[] = "<Mod4>";
  static const gchar text_mod5[] = "<Mod5>";
  static const gchar text_meta[] = "<Meta>";
  static const gchar text_super[] = "<Super>";
  static const gchar text_hyper[] = "<Hyper>";
  GdkModifierType saved_mods;
  guint l;
  const char *keyval_name;
  gchar *accelerator;

  accelerator_mods &= GDK_MODIFIER_MASK;

  keyval_name = gdk_keyval_name (gdk_keyval_to_lower (accelerator_key));
  if (!keyval_name)
    keyval_name = "";

  saved_mods = accelerator_mods;
  l = 0;
  if (accelerator_mods & _gtk_get_primary_accel_mod ())
    {
      l += sizeof (text_primary) - 1;
      accelerator_mods &= ~_gtk_get_primary_accel_mod (); /* consume the default accel */
    }
  if (accelerator_mods & GDK_SHIFT_MASK)
    l += sizeof (text_shift) - 1;
  if (accelerator_mods & GDK_CONTROL_MASK)
    l += sizeof (text_control) - 1;
  if (accelerator_mods & GDK_MOD1_MASK)
    l += sizeof (text_mod1) - 1;
  if (accelerator_mods & GDK_MOD2_MASK)
    l += sizeof (text_mod2) - 1;
  if (accelerator_mods & GDK_MOD3_MASK)
    l += sizeof (text_mod3) - 1;
  if (accelerator_mods & GDK_MOD4_MASK)
    l += sizeof (text_mod4) - 1;
  if (accelerator_mods & GDK_MOD5_MASK)
    l += sizeof (text_mod5) - 1;
  l += strlen (keyval_name);
  if (accelerator_mods & GDK_META_MASK)
    l += sizeof (text_meta) - 1;
  if (accelerator_mods & GDK_HYPER_MASK)
    l += sizeof (text_hyper) - 1;
  if (accelerator_mods & GDK_SUPER_MASK)
    l += sizeof (text_super) - 1;

  accelerator = g_new (gchar, l + 1);

  accelerator_mods = saved_mods;
  l = 0;
  accelerator[l] = 0;
  if (accelerator_mods & _gtk_get_primary_accel_mod ())
    {
      strcpy (accelerator + l, text_primary);
      l += sizeof (text_primary) - 1;
      accelerator_mods &= ~_gtk_get_primary_accel_mod (); /* consume the default accel */
    }
  if (accelerator_mods & GDK_SHIFT_MASK)
    {
      strcpy (accelerator + l, text_shift);
      l += sizeof (text_shift) - 1;
    }
  if (accelerator_mods & GDK_CONTROL_MASK)
    {
      strcpy (accelerator + l, text_control);
      l += sizeof (text_control) - 1;
    }
  if (accelerator_mods & GDK_MOD1_MASK)
    {
      strcpy (accelerator + l, text_mod1);
      l += sizeof (text_mod1) - 1;
    }
  if (accelerator_mods & GDK_MOD2_MASK)
    {
      strcpy (accelerator + l, text_mod2);
      l += sizeof (text_mod2) - 1;
    }
  if (accelerator_mods & GDK_MOD3_MASK)
    {
      strcpy (accelerator + l, text_mod3);
      l += sizeof (text_mod3) - 1;
    }
  if (accelerator_mods & GDK_MOD4_MASK)
    {
      strcpy (accelerator + l, text_mod4);
      l += sizeof (text_mod4) - 1;
    }
  if (accelerator_mods & GDK_MOD5_MASK)
    {
      strcpy (accelerator + l, text_mod5);
      l += sizeof (text_mod5) - 1;
    }
  if (accelerator_mods & GDK_META_MASK)
    {
      strcpy (accelerator + l, text_meta);
      l += sizeof (text_meta) - 1;
    }
  if (accelerator_mods & GDK_HYPER_MASK)
    {
      strcpy (accelerator + l, text_hyper);
      l += sizeof (text_hyper) - 1;
    }
  if (accelerator_mods & GDK_SUPER_MASK)
    {
      strcpy (accelerator + l, text_super);
      l += sizeof (text_super) - 1;
    }
  strcpy (accelerator + l, keyval_name);

  return accelerator;
}

/**
 * gtk_accelerator_get_label_with_keycode:
 * @display: (allow-none): a #GdkDisplay or %NULL to use the default display
 * @accelerator_key: accelerator keyval
 * @keycode: accelerator keycode
 * @accelerator_mods: accelerator modifier mask
 *
 * Converts an accelerator keyval and modifier mask
 * into a (possibly translated) string that can be displayed to
 * a user, similarly to gtk_accelerator_get_label(), but handling
 * keycodes.
 *
 * This is only useful for system-level components, applications
 * should use gtk_accelerator_parse() instead.
 *
 * Returns: a newly-allocated string representing the accelerator.
 */
gchar *
gtk_accelerator_get_label_with_keycode (GdkDisplay      *display,
                                        guint            accelerator_key,
                                        guint            keycode,
                                        GdkModifierType  accelerator_mods)
{
  gchar *gtk_label;

  if (display == NULL)
    display = gdk_display_manager_get_default_display (gdk_display_manager_get ());

  gdk_keymap_add_virtual_modifiers (gdk_display_get_keymap (display), &accelerator_mods);
  gtk_label = gtk_accelerator_get_label (accelerator_key, accelerator_mods);

  if (!accelerator_key)
    {
      gchar *label;
      label = g_strdup_printf ("%s0x%02x", gtk_label, keycode);
      g_free (gtk_label);
      return label;
    }

  return gtk_label;
}

/* Underscores in key names are better displayed as spaces
 * E.g., Page_Up should be “Page Up”.
 *
 * Some keynames also have prefixes that are not suitable
 * for display, e.g XF86AudioMute, so strip those out, too.
 *
 * This function is only called on untranslated keynames,
 * so no need to be UTF-8 safe.
 */
static void
append_without_underscores (GString    *s,
                            const char *str)
{
  const char *p;

  if (g_str_has_prefix (str, "XF86"))
    p = str + 4;
  else if (g_str_has_prefix (str, "ISO_"))
    p = str + 4;
  else
    p = str;

  for ( ; *p; p++)
    {
      if (*p == '_')
        g_string_append_c (s, ' ');
      else
        g_string_append_c (s, *p);
    }
}

/* On Mac, if the key has symbolic representation (e.g. arrow keys),
 * append it to gstring and return TRUE; otherwise return FALSE.
 * See http://docs.info.apple.com/article.html?path=Mac/10.5/en/cdb_symbs.html
 * for the list of special keys. */
static gboolean
append_keyval_symbol (guint    accelerator_key,
                      GString *gstring)
{
#ifdef GDK_WINDOWING_QUARTZ
  switch (accelerator_key)
  {
  case GDK_KEY_Return:
    /* U+21A9 LEFTWARDS ARROW WITH HOOK */
    g_string_append (gstring, "\xe2\x86\xa9");
    return TRUE;

  case GDK_KEY_ISO_Enter:
    /* U+2324 UP ARROWHEAD BETWEEN TWO HORIZONTAL BARS */
    g_string_append (gstring, "\xe2\x8c\xa4");
    return TRUE;

  case GDK_KEY_Left:
    /* U+2190 LEFTWARDS ARROW */
    g_string_append (gstring, "\xe2\x86\x90");
    return TRUE;

  case GDK_KEY_Up:
    /* U+2191 UPWARDS ARROW */
    g_string_append (gstring, "\xe2\x86\x91");
    return TRUE;

  case GDK_KEY_Right:
    /* U+2192 RIGHTWARDS ARROW */
    g_string_append (gstring, "\xe2\x86\x92");
    return TRUE;

  case GDK_KEY_Down:
    /* U+2193 DOWNWARDS ARROW */
    g_string_append (gstring, "\xe2\x86\x93");
    return TRUE;

  case GDK_KEY_Page_Up:
    /* U+21DE UPWARDS ARROW WITH DOUBLE STROKE */
    g_string_append (gstring, "\xe2\x87\x9e");
    return TRUE;

  case GDK_KEY_Page_Down:
    /* U+21DF DOWNWARDS ARROW WITH DOUBLE STROKE */
    g_string_append (gstring, "\xe2\x87\x9f");
    return TRUE;

  case GDK_KEY_Home:
    /* U+2196 NORTH WEST ARROW */
    g_string_append (gstring, "\xe2\x86\x96");
    return TRUE;

  case GDK_KEY_End:
    /* U+2198 SOUTH EAST ARROW */
    g_string_append (gstring, "\xe2\x86\x98");
    return TRUE;

  case GDK_KEY_Escape:
    /* U+238B BROKEN CIRCLE WITH NORTHWEST ARROW */
    g_string_append (gstring, "\xe2\x8e\x8b");
    return TRUE;

  case GDK_KEY_BackSpace:
    /* U+232B ERASE TO THE LEFT */
    g_string_append (gstring, "\xe2\x8c\xab");
    return TRUE;

  case GDK_KEY_Delete:
    /* U+2326 ERASE TO THE RIGHT */
    g_string_append (gstring, "\xe2\x8c\xa6");
    return TRUE;

  default:
    return FALSE;
  }
#else /* !GDK_WINDOWING_QUARTZ */
  return FALSE;
#endif
}

static void
append_separator (GString *string)
{
#ifndef GDK_WINDOWING_QUARTZ
  g_string_append (string, "+");
#else
  /* no separator on quartz */
#endif
}

/**
 * gtk_accelerator_get_label:
 * @accelerator_key: accelerator keyval
 * @accelerator_mods: accelerator modifier mask
 *
 * Converts an accelerator keyval and modifier mask into a string
 * which can be used to represent the accelerator to the user.
 *
 * Returns: a newly-allocated string representing the accelerator.
 */
gchar*
gtk_accelerator_get_label (guint           accelerator_key,
                           GdkModifierType accelerator_mods)
{
  GString *gstring;

  gstring = g_string_new (NULL);

  gtk_accelerator_print_label (gstring, accelerator_key, accelerator_mods);

  return g_string_free (gstring, FALSE);
}

void
gtk_accelerator_print_label (GString        *gstring,
                             guint           accelerator_key,
                             GdkModifierType accelerator_mods)
{
  gboolean seen_mod = FALSE;
  gunichar ch;

  if (accelerator_mods & GDK_SHIFT_MASK)
    {
#ifndef GDK_WINDOWING_QUARTZ
      /* This is the text that should appear next to menu accelerators
       * that use the shift key. If the text on this key isn't typically
       * translated on keyboards used for your language, don't translate
       * this.
       */
      g_string_append (gstring, C_("keyboard label", "Shift"));
#else
      /* U+21E7 UPWARDS WHITE ARROW */
      g_string_append (gstring, "\xe2\x87\xa7");
#endif
      seen_mod = TRUE;
    }

  if (accelerator_mods & GDK_CONTROL_MASK)
    {
      if (seen_mod)
        append_separator (gstring);

#ifndef GDK_WINDOWING_QUARTZ
      /* This is the text that should appear next to menu accelerators
       * that use the control key. If the text on this key isn't typically
       * translated on keyboards used for your language, don't translate
       * this.
       */
      g_string_append (gstring, C_("keyboard label", "Ctrl"));
#else
      /* U+2303 UP ARROWHEAD */
      g_string_append (gstring, "\xe2\x8c\x83");
#endif
      seen_mod = TRUE;
    }

  if (accelerator_mods & GDK_MOD1_MASK)
    {
      if (seen_mod)
        append_separator (gstring);

#ifndef GDK_WINDOWING_QUARTZ
      /* This is the text that should appear next to menu accelerators
       * that use the alt key. If the text on this key isn't typically
       * translated on keyboards used for your language, don't translate
       * this.
       */
      g_string_append (gstring, C_("keyboard label", "Alt"));
#else
      /* U+2325 OPTION KEY */
      g_string_append (gstring, "\xe2\x8c\xa5");
#endif
      seen_mod = TRUE;
    }

  if (accelerator_mods & GDK_MOD2_MASK)
    {
      if (seen_mod)
        append_separator (gstring);

      g_string_append (gstring, "Mod2");
      seen_mod = TRUE;
    }

  if (accelerator_mods & GDK_MOD3_MASK)
    {
      if (seen_mod)
        append_separator (gstring);

      g_string_append (gstring, "Mod3");
      seen_mod = TRUE;
    }

  if (accelerator_mods & GDK_MOD4_MASK)
    {
      if (seen_mod)
        append_separator (gstring);

      g_string_append (gstring, "Mod4");
      seen_mod = TRUE;
    }

  if (accelerator_mods & GDK_MOD5_MASK)
    {
      if (seen_mod)
        append_separator (gstring);

      g_string_append (gstring, "Mod5");
      seen_mod = TRUE;
    }

  if (accelerator_mods & GDK_SUPER_MASK)
    {
      if (seen_mod)
        append_separator (gstring);

      /* This is the text that should appear next to menu accelerators
       * that use the super key. If the text on this key isn't typically
       * translated on keyboards used for your language, don't translate
       * this.
       */
      g_string_append (gstring, C_("keyboard label", "Super"));
      seen_mod = TRUE;
    }

  if (accelerator_mods & GDK_HYPER_MASK)
    {
      if (seen_mod)
        append_separator (gstring);

      /* This is the text that should appear next to menu accelerators
       * that use the hyper key. If the text on this key isn't typically
       * translated on keyboards used for your language, don't translate
       * this.
       */
      g_string_append (gstring, C_("keyboard label", "Hyper"));
      seen_mod = TRUE;
    }

  if (accelerator_mods & GDK_META_MASK)
    {
      if (seen_mod)
        append_separator (gstring);

#ifndef GDK_WINDOWING_QUARTZ
      /* This is the text that should appear next to menu accelerators
       * that use the meta key. If the text on this key isn't typically
       * translated on keyboards used for your language, don't translate
       * this.
       */
      g_string_append (gstring, C_("keyboard label", "Meta"));
#else
      /* Command key symbol U+2318 PLACE OF INTEREST SIGN */
      g_string_append (gstring, "\xe2\x8c\x98");
#endif
      seen_mod = TRUE;
    }

  ch = gdk_keyval_to_unicode (accelerator_key);
  if (ch && (ch == ' ' || g_unichar_isgraph (ch)))
    {
      if (seen_mod)
        append_separator (gstring);

      switch (ch)
	{
	case ' ':
	  g_string_append (gstring, C_("keyboard label", "Space"));
	  break;
	case '\\':
	  g_string_append (gstring, C_("keyboard label", "Backslash"));
	  break;
	default:
	  g_string_append_unichar (gstring, g_unichar_toupper (ch));
	  break;
	}
    }
  else if (!append_keyval_symbol (accelerator_key, gstring))
    {
      const char *tmp;

      tmp = gdk_keyval_name (gdk_keyval_to_lower (accelerator_key));
      if (tmp != NULL)
	{
          if (seen_mod)
            append_separator (gstring);

	  if (tmp[0] != 0 && tmp[1] == 0)
	    g_string_append_c (gstring, g_ascii_toupper (tmp[0]));
	  else
	    {
	      const char *str;
              str = g_dpgettext2 (GETTEXT_PACKAGE, "keyboard label", tmp);
	      if (str == tmp)
                append_without_underscores (gstring, tmp);
	      else
		g_string_append (gstring, str);
	    }
	}
    }
}

/**
 * gtk_accelerator_set_default_mod_mask:
 * @default_mod_mask: accelerator modifier mask
 *
 * Sets the modifiers that will be considered significant for keyboard
 * accelerators. The default mod mask depends on the GDK backend in use,
 * but will typically include #GDK_CONTROL_MASK | #GDK_SHIFT_MASK |
 * #GDK_MOD1_MASK | #GDK_SUPER_MASK | #GDK_HYPER_MASK | #GDK_META_MASK.
 * In other words, Control, Shift, Alt, Super, Hyper and Meta. Other
 * modifiers will by default be ignored by #GtkAccelGroup.
 *
 * You must include at least the three modifiers Control, Shift
 * and Alt in any value you pass to this function.
 *
 * The default mod mask should be changed on application startup,
 * before using any accelerator groups.
 */
void
gtk_accelerator_set_default_mod_mask (GdkModifierType default_mod_mask)
{
  default_accel_mod_mask = (default_mod_mask & GDK_MODIFIER_MASK) |
    (GDK_CONTROL_MASK | GDK_SHIFT_MASK | GDK_MOD1_MASK);
}

/**
 * gtk_accelerator_get_default_mod_mask:
 *
 * Gets the modifier mask.
 *
 * The modifier mask determines which modifiers are considered significant
 * for keyboard accelerators. See gtk_accelerator_set_default_mod_mask().
 *
 * Returns: the default accelerator modifier mask
 */
GdkModifierType
gtk_accelerator_get_default_mod_mask (void)
{
  if (!default_accel_mod_mask)
    {
      GdkDisplay *display;

      display = gdk_display_get_default ();

      if (!display)
        return GDK_CONTROL_MASK | GDK_SHIFT_MASK | GDK_MOD1_MASK;

      default_accel_mod_mask =
          gdk_keymap_get_modifier_mask (gdk_display_get_keymap (display),
				        GDK_MODIFIER_INTENT_DEFAULT_MOD_MASK);
    }

  return default_accel_mod_mask;
}