[gnome-software/wip/jrocha/cancel-auto-refreshes-on-metered-connections] Cancel automatic refreshes if the network becomes metered

[Joaquim Manuel Pereira Rocha <jrocha src gnome org>]

commit 3e6e843b454c90d52f7a6c3eaf1da3eafad173c1
Author: Joaquim Rocha <jrocha endlessm com>
Date:   Mon Jan 15 17:25:01 2018 +0100

    Cancel automatic refreshes if the network becomes metered
    
    Refreshes may be used to download updates and that only happens in
    metered connections if the user configures it to do so. However, a
    refresh can take a while, so if it is started with an unmetered
    connection, and later the user connects to a metered one, we should make
    sure that the refresh operation is canceled (in order to avoid eventual
    fees).

 src/gs-update-monitor.c | 45 ++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 44 insertions(+), 1 deletion(-)
---
diff --git a/src/gs-update-monitor.c b/src/gs-update-monitor.c
index ee01d83e..7c49f924 100644
--- a/src/gs-update-monitor.c
+++ b/src/gs-update-monitor.c
@@ -39,6 +39,10 @@ struct _GsUpdateMonitor {
        GDBusProxy      *proxy_upower;
        GError          *last_offline_error;
 
+       GNetworkMonitor *network_monitor;
+       guint            network_changed_handler;
+       GCancellable    *network_cancellable;
+
        guint            cleanup_notifications_id;      /* at startup */
        guint            check_startup_id;              /* 60s after startup */
        guint            check_hourly_id;               /* and then every hour */
@@ -394,6 +398,10 @@ refresh_cache_finished_cb (GObject *object,
                        g_warning ("failed to refresh the cache: %s", error->message);
                return;
        }
+       if (g_cancellable_is_cancelled (monitor->network_cancellable)) {
+               g_clear_object (&monitor->network_cancellable);
+               monitor->network_cancellable = g_cancellable_new ();
+       }
        get_updates (monitor);
 }
 
@@ -488,7 +496,7 @@ check_updates (GsUpdateMonitor *monitor)
                                         "age", (guint64) (60 * 60 * 24),
                                         NULL);
        gs_plugin_loader_job_process_async (monitor->plugin_loader, plugin_job,
-                                           monitor->cancellable,
+                                           monitor->network_cancellable,
                                            refresh_cache_finished_cb,
                                            monitor);
 }
@@ -782,9 +790,21 @@ allow_updates_notify_cb (GsPluginLoader *plugin_loader,
        }
 }
 
+static void
+gs_update_monitor_network_changed_cb (GNetworkMonitor *network_monitor,
+                                     gboolean available,
+                                     GsUpdateMonitor *monitor)
+{
+       /* cancel an on-going refresh if we're now in a metered connection */
+       if (!g_settings_get_boolean (monitor->settings, "refresh-when-metered") &&
+           g_network_monitor_get_network_metered (network_monitor))
+               g_cancellable_cancel (monitor->network_cancellable);
+}
+
 static void
 gs_update_monitor_init (GsUpdateMonitor *monitor)
 {
+       GNetworkMonitor *network_monitor;
        g_autoptr(GError) error = NULL;
        monitor->settings = g_settings_new ("org.gnome.software");
 
@@ -796,7 +816,11 @@ gs_update_monitor_init (GsUpdateMonitor *monitor)
        monitor->check_startup_id =
                g_timeout_add_seconds (60, check_updates_on_startup_cb, monitor);
 
+       /* we use two cancellables because one can be cancelled by any network
+        * changes to a metered connection, and this shouldn't intervene with other
+        * operations */
        monitor->cancellable = g_cancellable_new ();
+       monitor->network_cancellable = g_cancellable_new ();
 
        /* connect to UPower to get the system power state */
        monitor->proxy_upower = g_dbus_proxy_new_for_bus_sync (G_BUS_TYPE_SYSTEM,
@@ -814,6 +838,15 @@ gs_update_monitor_init (GsUpdateMonitor *monitor)
        } else {
                g_warning ("failed to connect to upower: %s", error->message);
        }
+
+       network_monitor = g_network_monitor_get_default ();
+       if (network_monitor == NULL)
+               return;
+       monitor->network_monitor = g_object_ref (network_monitor);
+       monitor->network_changed_handler = g_signal_connect (monitor->network_monitor,
+                                                            "network-changed",
+                                                            G_CALLBACK 
(gs_update_monitor_network_changed_cb),
+                                                            monitor);
 }
 
 static void
@@ -821,10 +854,20 @@ gs_update_monitor_dispose (GObject *object)
 {
        GsUpdateMonitor *monitor = GS_UPDATE_MONITOR (object);
 
+       if (monitor->network_changed_handler != 0) {
+               g_signal_handler_disconnect (monitor->network_monitor,
+                                            monitor->network_changed_handler);
+               monitor->network_changed_handler = 0;
+       }
+
        if (monitor->cancellable) {
                g_cancellable_cancel (monitor->cancellable);
                g_clear_object (&monitor->cancellable);
        }
+       if (monitor->network_changed_handler) {
+               g_cancellable_cancel (monitor->network_cancellable);
+               g_clear_object (&monitor->network_cancellable);
+       }
 
        stop_updates_check (monitor);
        stop_upgrades_check (monitor);