[gnome-software: 13/29] repos: Make plugin setup asynchronous

[Philip Withnall <pwithnall src gnome org>]

commit fbac924163d216b057dd2fb15c9c7f20e893ec70
Author: Philip Withnall <pwithnall endlessos org>
Date:   Fri Oct 15 13:58:32 2021 +0100

    repos: Make plugin setup asynchronous
    
    Signed-off-by: Philip Withnall <pwithnall endlessos org>
    
    Helps: #1472

 plugins/repos/gs-plugin-repos.c | 71 +++++++++++++++++++++++++++++++++++------
 1 file changed, 62 insertions(+), 9 deletions(-)
---
diff --git a/plugins/repos/gs-plugin-repos.c b/plugins/repos/gs-plugin-repos.c
index b4babc394..751dd49c3 100644
--- a/plugins/repos/gs-plugin-repos.c
+++ b/plugins/repos/gs-plugin-repos.c
@@ -13,6 +13,20 @@
 
 #include "gs-plugin-repos.h"
 
+/*
+ * SECTION:
+ * Plugin to set URLs and origin hostnames on repos and apps using data from
+ * `/etc/yum.repos.d`
+ *
+ * This plugin is only useful on distributions which use `/etc/yum.repos.d`.
+ *
+ * It enumerates `/etc/yum.repos.d` in a worker thread and updates its internal
+ * hash tables and state from that worker thread (while holding a lock).
+ *
+ * Other tasks on the plugin access the data synchronously, not using a worker
+ * thread. Data accesses should be fast.
+ */
+
 struct _GsPluginRepos {
        GsPlugin         parent;
 
@@ -151,6 +165,7 @@ gs_plugin_repos_ensure_valid_locked (GsPluginRepos  *self,
        return TRUE;
 }
 
+/* Run in the main thread. */
 static void
 gs_plugin_repos_changed_cb (GFileMonitor      *monitor,
                             GFile             *file,
@@ -163,24 +178,58 @@ gs_plugin_repos_changed_cb (GFileMonitor      *monitor,
        g_atomic_int_set (&self->valid, FALSE);
 }
 
-gboolean
-gs_plugin_setup (GsPlugin *plugin, GCancellable *cancellable, GError **error)
+/* Run in a worker thread. */
+static void
+setup_thread_cb (GTask        *task,
+                 gpointer      source_object,
+                 gpointer      task_data,
+                 GCancellable *cancellable)
+{
+       GsPluginRepos *self = GS_PLUGIN_REPOS (source_object);
+       g_autoptr(GMutexLocker) locker = g_mutex_locker_new (&self->mutex);
+       g_autoptr(GError) local_error = NULL;
+
+       if (!gs_plugin_repos_ensure_valid_locked (self, cancellable, &local_error))
+               g_task_return_error (task, g_steal_pointer (&local_error));
+       else
+               g_task_return_boolean (task, TRUE);
+}
+
+static void
+gs_plugin_repos_setup_async (GsPlugin            *plugin,
+                             GCancellable        *cancellable,
+                             GAsyncReadyCallback  callback,
+                             gpointer             user_data)
 {
        GsPluginRepos *self = GS_PLUGIN_REPOS (plugin);
        g_autoptr(GFile) file = g_file_new_for_path (self->reposdir);
-       g_autoptr(GMutexLocker) locker = g_mutex_locker_new (&self->mutex);
+       g_autoptr(GTask) task = NULL;
+       g_autoptr(GError) local_error = NULL;
+
+       task = g_task_new (plugin, cancellable, callback, user_data);
+       g_task_set_source_tag (task, gs_plugin_repos_setup_async);
 
-       /* watch for changes */
-       self->monitor = g_file_monitor_directory (file, G_FILE_MONITOR_NONE, cancellable, error);
+       /* watch for changes in the main thread */
+       self->monitor = g_file_monitor_directory (file, G_FILE_MONITOR_NONE, cancellable, &local_error);
        if (self->monitor == NULL) {
-               gs_utils_error_convert_gio (error);
-               return FALSE;
+               gs_utils_error_convert_gio (&local_error);
+               g_task_return_error (task, g_steal_pointer (&local_error));
+               return;
        }
+
        g_signal_connect (self->monitor, "changed",
                          G_CALLBACK (gs_plugin_repos_changed_cb), self);
 
-       /* unconditionally at startup */
-       return gs_plugin_repos_ensure_valid_locked (self, cancellable, error);
+       /* Set up the repos at startup. */
+       g_task_run_in_thread (task, setup_thread_cb);
+}
+
+static gboolean
+gs_plugin_repos_setup_finish (GsPlugin      *plugin,
+                              GAsyncResult  *result,
+                              GError       **error)
+{
+       return g_task_propagate_boolean (G_TASK (result), error);
 }
 
 static gboolean
@@ -289,9 +338,13 @@ static void
 gs_plugin_repos_class_init (GsPluginReposClass *klass)
 {
        GObjectClass *object_class = G_OBJECT_CLASS (klass);
+       GsPluginClass *plugin_class = GS_PLUGIN_CLASS (klass);
 
        object_class->dispose = gs_plugin_repos_dispose;
        object_class->finalize = gs_plugin_repos_finalize;
+
+       plugin_class->setup_async = gs_plugin_repos_setup_async;
+       plugin_class->setup_finish = gs_plugin_repos_setup_finish;
 }
 
 GType