midori/katze/katze-utils.c

/*
 Copyright (C) 2007-2008 Christian Dywan <christian@twotoasts.de>

 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 2.1 of the License, or (at your option) any later version.

 See the file COPYING for the full license text.
*/

#include "katze-utils.h"

#include <glib/gi18n.h>

#include <string.h>

static void
proxy_toggle_button_toggled_cb (GtkToggleButton* button,
                                GObject*         object)
{
    gboolean toggled = gtk_toggle_button_get_active (button);
    const gchar* property = g_object_get_data (G_OBJECT (button), "property");
    g_object_set (object, property, toggled, NULL);
}

static void
proxy_file_file_set_cb (GtkFileChooser* button,
                        GObject*        object)
{
    const gchar* file = gtk_file_chooser_get_filename (button);
    const gchar* property = g_object_get_data (G_OBJECT (button), "property");
    g_object_set (object, property, file, NULL);
}

static void
proxy_folder_file_set_cb (GtkFileChooser* button,
                          GObject*        object)
{
    const gchar* file = gtk_file_chooser_get_current_folder (button);
    const gchar* property = g_object_get_data (G_OBJECT (button), "property");
    g_object_set (object, property, file, NULL);
}

static void
proxy_uri_file_set_cb (GtkFileChooser* button,
                       GObject*        object)
{
    const gchar* file = gtk_file_chooser_get_uri (button);
    const gchar* property = g_object_get_data (G_OBJECT (button), "property");
    g_object_set (object, property, file, NULL);
}

static void
proxy_combo_box_text_changed_cb (GtkComboBox* button,
                                 GObject*     object)
{
    gchar* text = gtk_combo_box_get_active_text (button);
    const gchar* property = g_object_get_data (G_OBJECT (button), "property");
    g_object_set (object, property, text, NULL);
}

static void
proxy_combo_box_apps_changed_cb (GtkComboBox* button,
                                 GObject*     object)
{
    guint active = gtk_combo_box_get_active (button);
    GtkTreeModel* model = gtk_combo_box_get_model (button);
    GtkTreeIter iter;

    if (gtk_tree_model_iter_nth_child (model, &iter, NULL, active))
    {
        GAppInfo* info;
        const gchar* exe;
        const gchar* property = g_object_get_data (G_OBJECT (button), "property");

        gtk_tree_model_get (model, &iter, 0, &info, -1);

        if (info)
        {
            #if 0 /* GLIB_CHECK_VERSION (2, 20, 0) */
            /* FIXME: Implement non-trivial command lines */
            exe = g_app_info_get_commandline (info);
            #else
            exe = g_app_info_get_executable (info);
            #endif
            g_object_set (object, property, exe, NULL);
            g_object_unref (info);
        }
        else
            g_object_set (object, property, "", NULL);
    }
}

static void
proxy_entry_activate_cb (GtkEntry* entry,
                         GObject*  object)
{
    const gchar* text = gtk_entry_get_text (entry);
    const gchar* property = g_object_get_data (G_OBJECT (entry), "property");
    g_object_set (object, property, text, NULL);
}

static gboolean
proxy_entry_focus_out_event_cb (GtkEntry*      entry,
                                GdkEventFocus* event,
                                GObject*       object)
{
    const gchar* text = gtk_entry_get_text (entry);
    const gchar* property = g_object_get_data (G_OBJECT (entry), "property");
    g_object_set (object, property, text, NULL);
    return FALSE;
}

static void
proxy_spin_button_changed_cb (GtkSpinButton* button,
                              GObject*       object)
{
    GObjectClass* class = G_OBJECT_GET_CLASS (object);
    const gchar* property = g_object_get_data (G_OBJECT (button), "property");
    GParamSpec* pspec = g_object_class_find_property (class, property);
    if (G_PARAM_SPEC_TYPE (pspec) == G_TYPE_PARAM_INT)
    {
        gint value = gtk_spin_button_get_value_as_int (button);
        g_object_set (object, property, value, NULL);
    }
    else
    {
        gdouble value = gtk_spin_button_get_value (button);
        g_object_set (object, property, value, NULL);
    }
}

static void
proxy_combo_box_changed_cb (GtkComboBox* button,
                            GObject*     object)
{
    gint value = gtk_combo_box_get_active (button);
    const gchar* property = g_object_get_data (G_OBJECT (button), "property");
    g_object_set (object, property, value, NULL);
}

static void
proxy_object_notify_boolean_cb (GObject*    object,
                                GParamSpec* pspec,
                                GtkWidget*  proxy)
{
    const gchar* property = g_object_get_data (G_OBJECT (proxy), "property");
    gboolean value = katze_object_get_boolean (object, property);
    gtk_toggle_button_set_active (GTK_TOGGLE_BUTTON (proxy), value);
}

static void
proxy_object_notify_string_cb (GObject*    object,
                               GParamSpec* pspec,
                               GtkWidget*  proxy)
{
    const gchar* property = g_object_get_data (G_OBJECT (proxy), "property");
    gchar* value = katze_object_get_string (object, property);
    gtk_entry_set_text (GTK_ENTRY (proxy), value);
    g_free (value);
}

static void
proxy_widget_boolean_destroy_cb (GtkWidget* proxy,
                                 GObject*   object)
{
    g_signal_handlers_disconnect_by_func (object,
        proxy_object_notify_boolean_cb, proxy);
}

static void
proxy_widget_string_destroy_cb (GtkWidget* proxy,
                                 GObject*  object)
{
    g_signal_handlers_disconnect_by_func (object,
        proxy_object_notify_string_cb, proxy);
}

static GList*
katze_app_info_get_all_for_category (const gchar* category)
{
    GList* all_apps = g_app_info_get_all ();
    GList* apps = NULL;
    guint i = 0;
    GAppInfo* info;
    while ((info = g_list_nth_data (all_apps, i++)))
    {
        #ifdef GDK_WINDOWING_X11
        gchar* filename = g_strconcat ("applications/", g_app_info_get_id (info), NULL);
        GKeyFile* file = g_key_file_new ();

        if (g_key_file_load_from_data_dirs (file, filename, NULL, G_KEY_FILE_NONE, NULL))
        {
            gchar* cat = g_key_file_get_string (file, "Desktop Entry",
                                                "Categories", NULL);
            if (cat && g_strrstr (cat, category))
                apps = g_list_append (apps, info);

            g_free (cat);
        }
        g_key_file_free (file);
        g_free (filename);
        #else
        apps = g_list_append (apps, info);
        #endif
    }
    g_list_free (all_apps);
    return apps;
}

/**
 * katze_property_proxy:
 * @object: a #GObject
 * @property: the name of a property
 * @hint: a special hint
 *
 * Create a widget of an appropriate type to represent the specified
 * object's property. If the property is writable changes of the value
 * through the widget will be reflected in the value of the property.
 *
 * Supported values for @hint are as follows:
 *     "blurb": the blurb of the property will be used to provide a kind
 *         of label, instead of the name.
 *     "file": the widget created will be particularly suitable for
 *         choosing an existing filename.
 *     "folder": the widget created will be particularly suitable for
 *         choosing an existing folder.
 *     "uri": the widget created will be particularly suitable for
 *         choosing an existing filename, encoded as an URI.
 *     "font": the widget created will be particularly suitable for
 *         choosing a variable-width font from installed fonts.
 *     Since 0.1.6 the following hints are also supported:
 *     "toggle": the widget created will be an empty toggle button. This
 *         is only supported with boolean properties.
 *         Since 0.1.8 "toggle" creates GtkCheckButton widgets without checkmarks.
 *     Since 0.2.0 the following hints are also supported:
 *     "font-monospace": the widget created will be particularly suitable for
 *         choosing a fixed-width font from installed fonts.
 *     Since 0.2.1 the following hints are also supported:
 *     "application-TYPE": the widget created will be particularly suitable
 *         for choosing an application to open TYPE files, ie. "text/plain".
 *     "application-CATEGORY": the widget created will be particularly suitable
 *         for choosing an application to open CATEGORY files, ie. "Network".
 *
 * Any other values for @hint are silently ignored.
 *
 * Since 0.1.2 strings without hints and booleans are truly synchronous
 * including property changes causing the proxy to be updated.
 *
 * Return value: a new widget
 **/
GtkWidget*
katze_property_proxy (gpointer     object,
                      const gchar* property,
                      const gchar* hint)
{
    GObjectClass* class;
    GParamSpec* pspec;
    GType type;
    const gchar* nick;
    const gchar* _hint;
    GtkWidget* widget;
    gchar* string;

    g_return_val_if_fail (G_IS_OBJECT (object), NULL);

    class = G_OBJECT_GET_CLASS (object);
    pspec = g_object_class_find_property (class, property);
    if (!pspec)
    {
        g_warning (_("Property '%s' is invalid for %s"),
                   property, G_OBJECT_CLASS_NAME (class));
        return gtk_label_new (property);
    }

    type = G_PARAM_SPEC_TYPE (pspec);
    nick = g_param_spec_get_nick (pspec);
    _hint = g_intern_string (hint);
    if (_hint == g_intern_string ("blurb"))
        nick = g_param_spec_get_blurb (pspec);
    string = NULL;
    if (type == G_TYPE_PARAM_BOOLEAN)
    {
        gchar* notify_property;
        gboolean toggled = katze_object_get_boolean (object, property);

        widget = gtk_check_button_new ();
        if (_hint == g_intern_string ("toggle"))
            gtk_toggle_button_set_mode (GTK_TOGGLE_BUTTON (widget), FALSE);
        else
            gtk_button_set_label (GTK_BUTTON (widget), gettext (nick));
        gtk_toggle_button_set_active (GTK_TOGGLE_BUTTON (widget), toggled);
        g_signal_connect (widget, "toggled",
                          G_CALLBACK (proxy_toggle_button_toggled_cb), object);
        notify_property = g_strdup_printf ("notify::%s", property);
        g_signal_connect (object, notify_property,
            G_CALLBACK (proxy_object_notify_boolean_cb), widget);
        g_signal_connect (widget, "destroy",
            G_CALLBACK (proxy_widget_boolean_destroy_cb), object);
        g_free (notify_property);
    }
    else if (type == G_TYPE_PARAM_STRING && _hint == g_intern_string ("file"))
    {
        string = katze_object_get_string (object, property);

        widget = gtk_file_chooser_button_new (_("Choose file"),
            GTK_FILE_CHOOSER_ACTION_OPEN);

        if (!string)
            string = g_strdup (G_PARAM_SPEC_STRING (pspec)->default_value);
        gtk_file_chooser_set_filename (GTK_FILE_CHOOSER (widget),
                                       string ? string : "");
        if (pspec->flags & G_PARAM_WRITABLE)
            g_signal_connect (widget, "selection-changed",
                              G_CALLBACK (proxy_file_file_set_cb), object);
    }
    else if (type == G_TYPE_PARAM_STRING && _hint == g_intern_string ("folder"))
    {
        string = katze_object_get_string (object, property);

        widget = gtk_file_chooser_button_new (_("Choose folder"),
            GTK_FILE_CHOOSER_ACTION_SELECT_FOLDER);
        if (!string)
            string = g_strdup (G_PARAM_SPEC_STRING (pspec)->default_value);
        gtk_file_chooser_set_current_folder (GTK_FILE_CHOOSER (widget),
                                             string ? string : "");
        if (pspec->flags & G_PARAM_WRITABLE)
            g_signal_connect (widget, "selection-changed",
                              G_CALLBACK (proxy_folder_file_set_cb), object);
    }
    else if (type == G_TYPE_PARAM_STRING && _hint == g_intern_string ("uri"))
    {
        string = katze_object_get_string (object, property);

        widget = gtk_file_chooser_button_new (_("Choose file"),
            GTK_FILE_CHOOSER_ACTION_OPEN);
        if (!string)
            string = g_strdup (G_PARAM_SPEC_STRING (pspec)->default_value);
        gtk_file_chooser_set_uri (GTK_FILE_CHOOSER (widget),
                                  string ? string : "");
        #if GTK_CHECK_VERSION (2, 12, 0)
        g_signal_connect (widget, "file-set",
                          G_CALLBACK (proxy_uri_file_set_cb), object);
        #else
        if (pspec->flags & G_PARAM_WRITABLE)
            g_signal_connect (widget, "selection-changed",
                              G_CALLBACK (proxy_uri_file_set_cb), object);
        #endif
    }
    else if (type == G_TYPE_PARAM_STRING && (_hint == g_intern_string ("font")
        || _hint == g_intern_string ("font-monospace")))
    {
        GtkComboBox* combo;
        gint n_families, i;
        PangoContext* context;
        PangoFontFamily** families;
        gboolean monospace = _hint == g_intern_string ("font-monospace");
        string = katze_object_get_string (object, property);

        widget = gtk_combo_box_new_text ();
        combo = GTK_COMBO_BOX (widget);
        context = gtk_widget_get_pango_context (widget);
        pango_context_list_families (context, &families, &n_families);
        if (!string)
            string = g_strdup (G_PARAM_SPEC_STRING (pspec)->default_value);
        if (string)
        {
            gint j = 0;
            for (i = 0; i < n_families; i++)
            {
                const gchar* font = pango_font_family_get_name (families[i]);
                if (monospace != pango_font_family_is_monospace (families[i]))
                    continue;
                gtk_combo_box_append_text (combo, font);
                if (!g_ascii_strcasecmp (font, string))
                    gtk_combo_box_set_active (combo, j);
                j++;
            }
        }
        gtk_tree_sortable_set_sort_column_id (GTK_TREE_SORTABLE (
            gtk_combo_box_get_model (combo)), 0, GTK_SORT_ASCENDING);
        g_signal_connect (widget, "changed",
                          G_CALLBACK (proxy_combo_box_text_changed_cb), object);
        g_free (families);
    }
    else if (type == G_TYPE_PARAM_STRING && hint && g_str_has_prefix (hint, "application-"))
    {
        GtkListStore* model;
        GtkCellRenderer* renderer;
        GtkComboBox* combo;
        GList* apps;
        const gchar* type = &hint[12];

        model = gtk_list_store_new (3, G_TYPE_APP_INFO, G_TYPE_STRING, G_TYPE_STRING);
        widget = gtk_combo_box_new_with_model (GTK_TREE_MODEL (model));
        renderer = gtk_cell_renderer_pixbuf_new ();
        gtk_cell_layout_pack_start (GTK_CELL_LAYOUT (widget), renderer, FALSE);
        gtk_cell_layout_add_attribute (GTK_CELL_LAYOUT (widget), renderer, "icon-name", 1);
        renderer = gtk_cell_renderer_text_new ();
        gtk_cell_layout_pack_start (GTK_CELL_LAYOUT (widget), renderer, TRUE);
        gtk_cell_layout_add_attribute (GTK_CELL_LAYOUT (widget), renderer, "text", 2);
        combo = GTK_COMBO_BOX (widget);
        apps = g_app_info_get_all_for_type (type);
        if (!apps)
            apps = katze_app_info_get_all_for_category (type);

        string = katze_object_get_string (object, property);
        if (!g_strcmp0 (string, ""))
            katze_assign (string, NULL);

        if (apps)
        {
            GtkTreeIter iter_none;
            gint i = 0;
            GAppInfo* info;

            gtk_list_store_insert_with_values (model, &iter_none, 0,
                0, NULL, 1, NULL, 2, _("None"), -1);

            while ((info = g_list_nth_data (apps, i++)))
            {
                const gchar* name = g_app_info_get_name (info);
                GIcon* icon = g_app_info_get_icon (info);
                gchar* icon_name = g_icon_to_string (icon);
                GtkTreeIter iter;

                gtk_list_store_insert_with_values (model, &iter, G_MAXINT,
                    0, info, 1, icon_name, 2, name, -1);
                if (string && g_strrstr (g_app_info_get_executable (info), string))
                    gtk_combo_box_set_active_iter (combo, &iter);

                g_free (icon_name);
            }

            if (gtk_combo_box_get_active (combo) == -1)
            {
                if (string)
                    /* FIXME: Support custom command */;
                else
                    gtk_combo_box_set_active_iter (combo, &iter_none);
            }
        }
        g_list_free (apps);
        g_signal_connect (widget, "changed",
                          G_CALLBACK (proxy_combo_box_apps_changed_cb), object);
    }
    else if (type == G_TYPE_PARAM_STRING)
    {
        gchar* notify_property;

        widget = gtk_entry_new ();
        g_object_get (object, property, &string, NULL);
        if (!string)
            string = g_strdup (G_PARAM_SPEC_STRING (pspec)->default_value);
        gtk_entry_set_text (GTK_ENTRY (widget), string ? string : "");
        g_signal_connect (widget, "activate",
                          G_CALLBACK (proxy_entry_activate_cb), object);
        g_signal_connect (widget, "focus-out-event",
                          G_CALLBACK (proxy_entry_focus_out_event_cb), object);
        notify_property = g_strdup_printf ("notify::%s", property);
        g_signal_connect (object, notify_property,
            G_CALLBACK (proxy_object_notify_string_cb), widget);
        g_signal_connect (widget, "destroy",
            G_CALLBACK (proxy_widget_string_destroy_cb), object);
        g_free (notify_property);
    }
    else if (type == G_TYPE_PARAM_FLOAT)
    {
        gfloat value = katze_object_get_float (object, property);

        widget = gtk_spin_button_new_with_range (
            G_PARAM_SPEC_FLOAT (pspec)->minimum,
            G_PARAM_SPEC_FLOAT (pspec)->maximum, 1);
        /* Keep it narrow, 5 + 2 digits are usually fine */
        gtk_entry_set_width_chars (GTK_ENTRY (widget), 5 + 2);
        gtk_spin_button_set_digits (GTK_SPIN_BUTTON (widget), 2);
        gtk_spin_button_set_value (GTK_SPIN_BUTTON (widget), value);
        g_signal_connect (widget, "value-changed",
                          G_CALLBACK (proxy_spin_button_changed_cb), object);
    }
    else if (type == G_TYPE_PARAM_INT)
    {
        gint value = katze_object_get_int (object, property);

        widget = gtk_spin_button_new_with_range (
            G_PARAM_SPEC_INT (pspec)->minimum,
            G_PARAM_SPEC_INT (pspec)->maximum, 1);
        /* Keep it narrow, 5 digits are usually fine */
        gtk_entry_set_width_chars (GTK_ENTRY (widget), 5);
        gtk_spin_button_set_value (GTK_SPIN_BUTTON (widget), value);
        g_signal_connect (widget, "value-changed",
                          G_CALLBACK (proxy_spin_button_changed_cb), object);
    }
    else if (type == G_TYPE_PARAM_ENUM)
    {
        guint i;
        GEnumClass* enum_class = G_ENUM_CLASS (
            g_type_class_ref (pspec->value_type));
        gint value = katze_object_get_enum (object, property);

        widget = gtk_combo_box_new_text ();
        for (i = 0; i < enum_class->n_values; i++)
        {
            const gchar* label = gettext (enum_class->values[i].value_nick);
            gtk_combo_box_append_text (GTK_COMBO_BOX (widget), label);
        }
        gtk_combo_box_set_active (GTK_COMBO_BOX (widget), value);
        g_signal_connect (widget, "changed",
                          G_CALLBACK (proxy_combo_box_changed_cb), object);
        g_type_class_unref (enum_class);
    }
    else
        widget = gtk_label_new (gettext (nick));
    g_free (string);

    gtk_widget_set_tooltip_text (widget, g_param_spec_get_blurb (pspec));
    gtk_widget_set_sensitive (widget, pspec->flags & G_PARAM_WRITABLE);

    g_object_set_data_full (G_OBJECT (widget), "property",
                            g_strdup (property), g_free);

    return widget;
}

/**
 * katze_property_label:
 * @object: a #GObject
 * @property: the name of a property
 *
 * Create a label widget displaying the name of the specified object's property.
 *
 * Return value: a new label widget
 **/
GtkWidget*
katze_property_label (gpointer     object,
                      const gchar* property)
{
    GObjectClass* class;
    GParamSpec* pspec;
    const gchar* nick;
    GtkWidget* widget;

    g_return_val_if_fail (G_IS_OBJECT (object), NULL);

    class = G_OBJECT_GET_CLASS (object);
    pspec = g_object_class_find_property (class, property);
    if (!pspec)
    {
        g_warning (_("Property '%s' is invalid for %s"),
                   property, G_OBJECT_CLASS_NAME (class));
        return gtk_label_new (property);
    }
    nick = g_param_spec_get_nick (pspec);
    widget = gtk_label_new (nick);
    gtk_misc_set_alignment (GTK_MISC (widget), 0.0, 0.5);

    return widget;
}

typedef struct
{
     GtkWidget* widget;
     KatzeMenuPos position;
} KatzePopupInfo;

static void
katze_widget_popup_position_menu (GtkMenu*  menu,
                                  gint*     x,
                                  gint*     y,
                                  gboolean* push_in,
                                  gpointer  user_data)
{
    gint wx, wy;
    gint menu_width;
    GtkRequisition menu_req;
    GtkRequisition widget_req;
    KatzePopupInfo* info = user_data;
    GtkWidget* widget = info->widget;
    gint widget_height;

    /* Retrieve size and position of both widget and menu */
    if (GTK_WIDGET_NO_WINDOW (widget))
    {
        gdk_window_get_position (widget->window, &wx, &wy);
        wx += widget->allocation.x;
        wy += widget->allocation.y;
    }
    else
        gdk_window_get_origin (widget->window, &wx, &wy);
    gtk_widget_size_request (GTK_WIDGET (menu), &menu_req);
    gtk_widget_size_request (widget, &widget_req);
    menu_width = menu_req.width;
    widget_height = widget_req.height; /* Better than allocation.height */

    /* Calculate menu position */
    if (info->position == KATZE_MENU_POSITION_CURSOR)
        ; /* Do nothing? */
    else if (info->position == KATZE_MENU_POSITION_RIGHT)
    {
        *x = wx + widget->allocation.width - menu_width;
        *y = wy + widget_height;
    } else if (info->position == KATZE_MENU_POSITION_LEFT)
    {
        *x = wx;
        *y = wy + widget_height;
    }

    *push_in = TRUE;
}

/**
 * katze_widget_popup:
 * @widget: a widget
 * @menu: the menu to popup
 * @event: a button event, or %NULL
 * @pos: the preferred positioning
 *
 * Pops up the given menu relative to @widget. Use this
 * instead of writing custom positioning functions.
 *
 * Return value: a new label widget
 **/
void
katze_widget_popup (GtkWidget*      widget,
                    GtkMenu*        menu,
                    GdkEventButton* event,
                    KatzeMenuPos    pos)
{
    int button, event_time;
    if (event)
    {
        button = event->button;
        event_time = event->time;
    }
    else
    {
        button = 0;
        event_time = gtk_get_current_event_time ();
    }

    if (!gtk_menu_get_attach_widget (menu))
        gtk_menu_attach_to_widget (menu, widget, NULL);


    if (widget)
    {
        KatzePopupInfo info = { widget, pos };
        gtk_menu_popup (menu, NULL, NULL,
                        katze_widget_popup_position_menu, &info,
                        button, event_time);
    }
    else
        gtk_menu_popup (menu, NULL, NULL, NULL, NULL, button, event_time);
}

/**
 * katze_image_menu_item_new_ellipsized:
 * @label: a label or %NULL
 *
 * Creates an image menu item where the label is
 * reasonably ellipsized for you.
 *
 * Return value: a new label widget
 **/
GtkWidget*
katze_image_menu_item_new_ellipsized (const gchar* label)
{
    GtkWidget* menuitem;
    GtkWidget* label_widget;

    menuitem = gtk_image_menu_item_new ();
    label_widget = gtk_label_new (label);
    /* FIXME: Should text direction be respected here? */
    gtk_misc_set_alignment (GTK_MISC (label_widget), 0.0, 0.0);
    gtk_label_set_max_width_chars (GTK_LABEL (label_widget), 50);
    gtk_label_set_ellipsize (GTK_LABEL (label_widget), PANGO_ELLIPSIZE_MIDDLE);
    gtk_widget_show (label_widget);
    gtk_container_add (GTK_CONTAINER (menuitem), label_widget);

    return menuitem;
}

/**
 * katze_pixbuf_new_from_buffer:
 * @buffer: Buffer with image data
 * @length: Length of the buffer
 * @mime_type: a MIME type, or %NULL
 * @error: return location for a #GError, or %NULL
 *
 * Creates a new #GdkPixbuf out of the specified buffer.
 *
 * You can specify a MIME type if looking at the buffer
 * is not enough to determine the right type.
 *
 * Return value: A newly-allocated #GdkPixbuf
 **/
GdkPixbuf*
katze_pixbuf_new_from_buffer (const guchar* buffer,
                              gsize         length,
                              const gchar*  mime_type,
                              GError**      error)
{
    /* Proposed for inclusion in GdkPixbuf
       See http://bugzilla.gnome.org/show_bug.cgi?id=74291 */
    GdkPixbufLoader* loader;
    GdkPixbuf* pixbuf;

    g_return_val_if_fail (buffer != NULL, NULL);
    g_return_val_if_fail (length > 0, NULL);

    if (mime_type)
    {
        loader = gdk_pixbuf_loader_new_with_mime_type (mime_type, error);
        if (!loader)
            return NULL;
    }
    else
        loader = gdk_pixbuf_loader_new ();
    if (!gdk_pixbuf_loader_write (loader, buffer, length, error))
    {
        g_object_unref (loader);
        return NULL;
    }
    if (!gdk_pixbuf_loader_close (loader, error))
    {
        g_object_unref (loader);
        return NULL;
    }

    pixbuf = gdk_pixbuf_loader_get_pixbuf (loader);
    g_object_ref (pixbuf);
    g_object_unref (loader);
    return pixbuf;
}

/**
 * katze_tree_view_get_selected_iter:
 * @treeview: a #GtkTreeView
 * @model: a pointer to store the model, or %NULL
 * @iter: a pointer to store the iter, or %NULL
 *
 * Determines whether there is a selection in @treeview
 * and sets the @iter to the current selection.
 *
 * If there is a selection and @model is not %NULL, it is
 * set to the model, mainly for convenience.
 *
 * Either @model or @iter or both can be %NULL in which case
 * no value will be assigned in any case.
 *
 * Return value: %TRUE if there is a selection
 *
 * Since: 0.1.3
 **/
gboolean
katze_tree_view_get_selected_iter (GtkTreeView*   treeview,
                                   GtkTreeModel** model,
                                   GtkTreeIter*   iter)
{
    GtkTreeSelection* selection;

    g_return_val_if_fail (GTK_IS_TREE_VIEW (treeview), FALSE);

    if ((selection = gtk_tree_view_get_selection (treeview)))
        if (gtk_tree_selection_get_selected (selection, model, iter))
            return TRUE;
    return FALSE;
}

/**
 * katze_strip_mnemonics:
 * @original: a string with mnemonics
 *
 * Parses the given string for mnemonics in the form
 * "B_utton" or "Button (_U)" and returns a string
 * without any mnemonics.
 *
 * Return value: a newly allocated string without mnemonics
 *
 * Since: 0.1.8
 **/
gchar*
katze_strip_mnemonics (const gchar* original)
{
  /* A copy of _gtk_toolbar_elide_underscores
     Copyright (C) 1995-1997 Peter Mattis, Spencer Kimball and Josh MacDonald
     Copied from GTK+ 2.17.1 */
  gchar *q, *result;
  const gchar *p, *end;
  gsize len;
  gboolean last_underscore;

  if (!original)
    return NULL;

  len = strlen (original);
  q = result = g_malloc (len + 1);
  last_underscore = FALSE;

  end = original + len;
  for (p = original; p < end; p++)
    {
      if (!last_underscore && *p == '_')
	last_underscore = TRUE;
      else
	{
	  last_underscore = FALSE;
	  if (original + 2 <= p && p + 1 <= end &&
              p[-2] == '(' && p[-1] == '_' && p[0] != '_' && p[1] == ')')
	    {
	      q--;
	      *q = '\0';
	      p++;
	    }
	  else
	    *q++ = *p;
	}
    }

  if (last_underscore)
    *q++ = '_';

  *q = '\0';

  return result;
}

/**
 * katze_object_has_property:
 * @object: a #GObject
 * @property: the name of the property
 *
 * Determine if @object has a property with the specified name.
 *
 * Return value: a boolean
 *
 * Since: 0.1.2
 **/
gboolean
katze_object_has_property (gpointer     object,
                           const gchar* property)
{
    GObjectClass* class;

    g_return_val_if_fail (G_IS_OBJECT (object), FALSE);

    class = G_OBJECT_GET_CLASS (object);
    return g_object_class_find_property (class, property) != NULL;
}

/**
 * katze_object_get_boolean:
 * @object: a #GObject
 * @property: the name of the property to get
 *
 * Retrieve the boolean value of the specified property.
 *
 * Return value: a boolean
 **/
gboolean
katze_object_get_boolean (gpointer     object,
                          const gchar* property)
{
    gboolean value = FALSE;

    g_return_val_if_fail (G_IS_OBJECT (object), FALSE);
    /* FIXME: Check value type */

    g_object_get (object, property, &value, NULL);
    return value;
}

/**
 * katze_object_get_int:
 * @object: a #GObject
 * @property: the name of the property to get
 *
 * Retrieve the integer value of the specified property.
 *
 * Return value: an integer
 **/
gint
katze_object_get_int (gpointer     object,
                      const gchar* property)
{
    gint value = -1;

    g_return_val_if_fail (G_IS_OBJECT (object), -1);
    /* FIXME: Check value type */

    g_object_get (object, property, &value, NULL);
    return value;
}

/**
 * katze_object_get_float:
 * @object: a #GObject
 * @property: the name of the property to get
 *
 * Retrieve the float value of the specified property.
 *
 * Return value: a float
 **/
gfloat
katze_object_get_float (gpointer     object,
                        const gchar* property)
{
    gfloat value = -1.0f;

    g_return_val_if_fail (G_IS_OBJECT (object), -1.0f);
    /* FIXME: Check value type */

    g_object_get (object, property, &value, NULL);
    return value;
}

/**
 * katze_object_get_enum:
 * @object: a #GObject
 * @property: the name of the property to get
 *
 * Retrieve the enum value of the specified property.
 *
 * Return value: an enumeration
 **/
gint
katze_object_get_enum (gpointer     object,
                       const gchar* property)
{
    gint value = -1;

    g_return_val_if_fail (G_IS_OBJECT (object), -1);
    /* FIXME: Check value type */

    g_object_get (object, property, &value, NULL);
    return value;
}

/**
 * katze_object_get_string:
 * @object: a #GObject
 * @property: the name of the property to get
 *
 * Retrieve the string value of the specified property.
 *
 * Return value: a newly allocated string
 **/
gchar*
katze_object_get_string (gpointer     object,
                         const gchar* property)
{
    gchar* value = NULL;

    g_return_val_if_fail (G_IS_OBJECT (object), NULL);
    /* FIXME: Check value type */

    g_object_get (object, property, &value, NULL);
    return value;
}

/**
 * katze_object_get_object:
 * @object: a #GObject
 * @property: the name of the property to get
 *
 * Retrieve the object value of the specified property.
 *
 * Return value: an object
 **/
gpointer
katze_object_get_object (gpointer     object,
                         const gchar* property)
{
    GObject* value = NULL;

    g_return_val_if_fail (G_IS_OBJECT (object), NULL);
    /* FIXME: Check value type */

    g_object_get (object, property, &value, NULL);
    return value;
}