[gnome-software/gnome-3-30] Only emit updates-changed once, after all task have completed

[Kalev Lember <klember src gnome org>]

commit 67b0914443c7769714c0c382d63aa992e4466549
Author: Richard Hughes <richard hughsie com>
Date:   Tue Aug 14 10:07:24 2018 +0100

    Only emit updates-changed once, after all task have completed
    
    This should prevent the fork-bomb that happens when multiple flatpak
    transactions emit updates-changed, which causes the update monitor to reget the
    update list and then update the same list of applications, IN A LOOP.
    
    Fixes https://gitlab.gnome.org/GNOME/gnome-software/issues/443

 lib/gs-plugin-loader.c | 17 +++++++++++++++--
 1 file changed, 15 insertions(+), 2 deletions(-)
---
diff --git a/lib/gs-plugin-loader.c b/lib/gs-plugin-loader.c
index 5916c0fe..02be77ba 100644
--- a/lib/gs-plugin-loader.c
+++ b/lib/gs-plugin-loader.c
@@ -67,6 +67,7 @@ typedef struct
        guint                    scale;
 
        guint                    updates_changed_id;
+       guint                    updates_changed_cnt;
        guint                    reload_id;
        GHashTable              *disallow_updates;      /* GsPlugin : const char *name */
 
@@ -2076,14 +2077,21 @@ gs_plugin_loader_job_actions_changed_delay_cb (gpointer user_data)
        g_debug ("updates-changed");
        g_signal_emit (plugin_loader, signals[SIGNAL_UPDATES_CHANGED], 0);
        priv->updates_changed_id = 0;
+       priv->updates_changed_cnt = 0;
 
        g_object_unref (plugin_loader);
        return FALSE;
 }
 
 static void
-gs_plugin_loader_job_actions_changed_cb (GsPlugin *plugin,
-                                    GsPluginLoader *plugin_loader)
+gs_plugin_loader_job_actions_changed_cb (GsPlugin *plugin, GsPluginLoader *plugin_loader)
+{
+       GsPluginLoaderPrivate *priv = gs_plugin_loader_get_instance_private (plugin_loader);
+       priv->updates_changed_cnt++;
+}
+
+static void
+gs_plugin_loader_updates_changed (GsPluginLoader *plugin_loader)
 {
        GsPluginLoaderPrivate *priv = gs_plugin_loader_get_instance_private (plugin_loader);
        if (priv->updates_changed_id != 0)
@@ -3105,6 +3113,7 @@ gs_plugin_loader_process_thread_cb (GTask *task,
        GsAppList *list = gs_plugin_job_get_list (helper->plugin_job);
        GsPluginAction action = gs_plugin_job_get_action (helper->plugin_job);
        GsPluginLoader *plugin_loader = GS_PLUGIN_LOADER (object);
+       GsPluginLoaderPrivate *priv = gs_plugin_loader_get_instance_private (plugin_loader);
        GsPluginRefineFlags filter_flags;
        GsPluginRefineFlags refine_flags;
        gboolean add_to_pending_array = FALSE;
@@ -3410,6 +3419,10 @@ gs_plugin_loader_process_thread_cb (GTask *task,
        /* sort these again as the refine may have added useful metadata */
        gs_plugin_loader_job_sorted_truncation_again (helper);
 
+       /* if the plugin used updates-changed actually schedule it now */
+       if (priv->updates_changed_cnt > 0)
+               gs_plugin_loader_updates_changed (plugin_loader);
+
        /* show elapsed time */
        gs_plugin_loader_job_debug (helper);