[eog] reload: Only offer reload option if there's something to reload

[Felix Riemann <friemann src gnome org>]

commit cf429103e1544c8c9de17110a29e1a7e7734dfba
Author: Felix Riemann <friemann gnome org>
Date:   Tue Sep 29 16:33:42 2015 +0200

    reload: Only offer reload option if there's something to reload
    
    https://bugzilla.gnome.org/show_bug.cgi?id=755244

 plugins/reload/eog-reload-plugin.c |   40 ++++++++++++++++++++++++++++++++++++
 1 files changed, 40 insertions(+), 0 deletions(-)
---
diff --git a/plugins/reload/eog-reload-plugin.c b/plugins/reload/eog-reload-plugin.c
index 3d9aca2..456542b 100644
--- a/plugins/reload/eog-reload-plugin.c
+++ b/plugins/reload/eog-reload-plugin.c
@@ -32,6 +32,7 @@
 
 #include <eog-application.h>
 #include <eog-debug.h>
+#include <eog-thumb-view.h>
 #include <eog-window.h>
 #include <eog-window-activatable.h>
 
@@ -122,6 +123,34 @@ eog_reload_plugin_dispose (GObject *object)
 }
 
 static void
+eog_reload_plugin_update_action_state (EogReloadPlugin *plugin)
+{
+       GAction *action;
+       EogThumbView *thumbview;
+       gboolean enable = FALSE;
+
+       thumbview = EOG_THUMB_VIEW (eog_window_get_thumb_view (plugin->window));
+
+       if (G_LIKELY (thumbview))
+       {
+               enable = (eog_thumb_view_get_n_selected (thumbview) != 0);
+       }
+
+       action = g_action_map_lookup_action (G_ACTION_MAP (plugin->window),
+                                            EOG_RELOAD_PLUGIN_ACTION);
+       g_simple_action_set_enabled (G_SIMPLE_ACTION (action), enable);
+}
+
+static void
+_selection_changed_cb (EogThumbView *thumbview, gpointer user_data)
+{
+       EogReloadPlugin *plugin = EOG_RELOAD_PLUGIN (user_data);
+
+       if (G_LIKELY (plugin))
+               eog_reload_plugin_update_action_state (plugin);
+}
+
+static void
 eog_reload_plugin_activate (EogWindowActivatable *activatable)
 {
        const gchar * const accel_keys[] = { "R", NULL };
@@ -145,6 +174,12 @@ eog_reload_plugin_activate (EogWindowActivatable *activatable)
                                 G_ACTION (action));
        g_object_unref (action);
 
+       g_signal_connect (G_OBJECT (eog_window_get_thumb_view (plugin->window)),
+                         "selection-changed",
+                         G_CALLBACK (_selection_changed_cb),
+                         plugin);
+       eog_reload_plugin_update_action_state (plugin);
+
        /* Append entry to the window's gear menu */
        menu = g_menu_new ();
        g_menu_append (menu, _("Reload Image"),
@@ -203,6 +238,11 @@ eog_reload_plugin_deactivate (EogWindowActivatable *activatable)
                                              "win." EOG_RELOAD_PLUGIN_ACTION,
                                              empty_accels);
 
+       /* Disconnect selection-changed handler as the thumbview would
+        * otherwise still cause callbacks during its own disposal */
+       g_signal_handlers_disconnect_by_func (eog_window_get_thumb_view (plugin->window),
+                                             _selection_changed_cb, plugin);
+
        /* Finally remove action */
        g_action_map_remove_action (G_ACTION_MAP (plugin->window),
                                    EOG_RELOAD_PLUGIN_ACTION);