[gnome-software] Monitor the AppStream directories and reload the cache if files are changed

[Richard Hughes <rhughes src gnome org>]

commit 8e739ff9ba69e964be25c10ead24568d47c184b2
Author: Richard Hughes <richard hughsie com>
Date:   Mon Nov 4 13:09:31 2013 +0000

    Monitor the AppStream directories and reload the cache if files are changed
    
    This is quite important now gnome-software is running as a service and makes
    it much easier to add or modify appstream XML files on a running system.

 src/plugins/gs-plugin-appstream.c |   45 +++++++++++++++++++++++++++++++++++-
 1 files changed, 43 insertions(+), 2 deletions(-)
---
diff --git a/src/plugins/gs-plugin-appstream.c b/src/plugins/gs-plugin-appstream.c
index 242a9aa..52509ed 100644
--- a/src/plugins/gs-plugin-appstream.c
+++ b/src/plugins/gs-plugin-appstream.c
@@ -32,6 +32,7 @@
 
 struct GsPluginPrivate {
        AppstreamCache          *cache;
+       GPtrArray               *file_monitors;
        gchar                   *cachedir;
        gsize                    done_init;
 };
@@ -145,17 +146,49 @@ out:
 }
 
 /**
+ * gs_plugin_appstream_cache_changed_cb:
+ */
+static void
+gs_plugin_appstream_cache_changed_cb (GFileMonitor *monitor,
+                                     GFile *file, GFile *other_file,
+                                     GFileMonitorEvent event_type,
+                                     GsPlugin *plugin)
+{
+       gchar *path;
+       path = g_file_get_path (file);
+       g_debug ("AppStream metadata %s changed, reloading cache", path);
+       plugin->priv->done_init = FALSE;
+       g_free (path);
+}
+
+/**
  * gs_plugin_parse_xml_dir:
  */
 static gboolean
 gs_plugin_parse_xml_dir (GsPlugin *plugin,
                         const gchar *path_xml,
                         const gchar *path_icons,
+                        GCancellable *cancellable,
                         GError **error)
 {
+       GDir *dir = NULL;
+       GFile *file_xml = NULL;
+       GFileMonitor *monitor = NULL;
        const gchar *tmp;
        gboolean ret = TRUE;
-       GDir *dir = NULL;
+
+       /* watch the directory for changes */
+       file_xml = g_file_new_for_path (path_xml);
+       monitor = g_file_monitor_directory (file_xml,
+                                           G_FILE_MONITOR_NONE,
+                                           cancellable,
+                                           error);
+       if (monitor == NULL)
+               goto out;
+       g_signal_connect (monitor, "changed",
+                         G_CALLBACK (gs_plugin_appstream_cache_changed_cb),
+                         plugin);
+       g_ptr_array_add (plugin->priv->file_monitors, g_object_ref (monitor));
 
        /* search all files */
        if (!g_file_test (path_xml, G_FILE_TEST_EXISTS))
@@ -176,6 +209,10 @@ gs_plugin_parse_xml_dir (GsPlugin *plugin,
                        goto out;
        }
 out:
+       if (file_xml != NULL)
+               g_object_unref (file_xml);
+       if (monitor != NULL)
+               g_object_unref (monitor);
        if (dir != NULL)
                g_dir_close (dir);
        return ret;
@@ -240,8 +277,8 @@ out:
 void
 gs_plugin_initialize (GsPlugin *plugin)
 {
-       /* create private area */
        plugin->priv = GS_PLUGIN_GET_PRIVATE (GsPluginPrivate);
+       plugin->priv->file_monitors = g_ptr_array_new_with_free_func ((GDestroyNotify) g_object_unref);
        plugin->priv->cache = appstream_cache_new ();
        plugin->priv->cachedir = g_build_filename (DATADIR,
                                                   "app-info",
@@ -266,6 +303,7 @@ gs_plugin_destroy (GsPlugin *plugin)
 {
        g_free (plugin->priv->cachedir);
        g_object_unref (plugin->priv->cache);
+       g_ptr_array_unref (plugin->priv->file_monitors);
 }
 
 /**
@@ -279,6 +317,9 @@ gs_plugin_startup (GsPlugin *plugin, GCancellable *cancellable, GError **error)
        gboolean ret;
        guint i;
 
+       /* clear all existing file monitors */
+       g_ptr_array_set_size (plugin->priv->file_monitors, 0);
+
        /* Parse the XML */
        gs_profile_start (plugin->profile, "appstream::startup");
        ret = gs_plugin_parse_xml (plugin, cancellable, error);