[tracker] tracker-miner-fs: Watch after tracker-extract process

[Carlos Garnacho <carlosg src gnome org>]

commit 32104d5cd83dc4a8de0c566de5a8aefa9fcaeba0
Author: Carlos Garnacho <carlosg gnome org>
Date:   Thu Dec 8 15:33:29 2016 +0100

    tracker-miner-fs: Watch after tracker-extract process
    
    Ensure it's restarted after going away (eg. due to unintended
    crashes), the extractor will eventually skip over the file and
    keep going.

 src/miners/fs/Makefile.am                |    2 +
 src/miners/fs/tracker-extract-watchdog.c |  157 ++++++++++++++++++++++++++++++
 src/miners/fs/tracker-extract-watchdog.h |   38 +++++++
 src/miners/fs/tracker-miner-files.c      |    6 +
 4 files changed, 203 insertions(+), 0 deletions(-)
---
diff --git a/src/miners/fs/Makefile.am b/src/miners/fs/Makefile.am
index 75060f1..c1dc2da 100644
--- a/src/miners/fs/Makefile.am
+++ b/src/miners/fs/Makefile.am
@@ -29,6 +29,8 @@ tracker_miner_fs_SOURCES =                             \
        $(power_headers)                               \
        tracker-config.c                               \
        tracker-config.h                               \
+       tracker-extract-watchdog.c                     \
+       tracker-extract-watchdog.h                     \
        tracker-main.c                                 \
        tracker-miner-files.c                          \
        tracker-miner-files.h                          \
diff --git a/src/miners/fs/tracker-extract-watchdog.c b/src/miners/fs/tracker-extract-watchdog.c
new file mode 100644
index 0000000..fd0b88f
--- /dev/null
+++ b/src/miners/fs/tracker-extract-watchdog.c
@@ -0,0 +1,157 @@
+/*
+ * Copyright (C) 2016, Red Hat Inc.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the
+ * Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
+ * Boston, MA  02110-1301, USA.
+ */
+
+#include "config.h"
+
+#include "tracker-extract-watchdog.h"
+
+#include <libtracker-common/tracker-common.h>
+#include <libtracker-miner/tracker-miner.h>
+
+struct _TrackerExtractWatchdog {
+       GObject parent_class;
+       guint extractor_watchdog_id;
+       guint timeout_id;
+       gboolean initializing;
+};
+
+static void extract_watchdog_start (TrackerExtractWatchdog *watchdog,
+                                   gboolean                autostart);
+
+G_DEFINE_TYPE (TrackerExtractWatchdog, tracker_extract_watchdog, G_TYPE_OBJECT)
+
+static void
+extract_watchdog_stop (TrackerExtractWatchdog *watchdog)
+{
+       if (watchdog->extractor_watchdog_id) {
+               g_bus_unwatch_name (watchdog->extractor_watchdog_id);
+               watchdog->extractor_watchdog_id = 0;
+       }
+}
+
+static gboolean
+extract_watchdog_name_vanished_timeout (gpointer user_data)
+{
+       TrackerExtractWatchdog *watchdog = user_data;
+
+       watchdog->timeout_id = 0;
+       extract_watchdog_start (watchdog, TRUE);
+
+       return G_SOURCE_REMOVE;
+}
+
+static void
+extract_watchdog_name_appeared (GDBusConnection *conn,
+                               const gchar     *name,
+                               const gchar     *name_owner,
+                               gpointer         user_data)
+{
+       TrackerExtractWatchdog *watchdog = user_data;
+
+       if (watchdog->initializing)
+               watchdog->initializing = FALSE;
+}
+
+static void
+extract_watchdog_name_vanished (GDBusConnection *conn,
+                               const gchar     *name,
+                               gpointer         user_data)
+{
+       TrackerExtractWatchdog *watchdog = user_data;
+
+       /* If connection is lost, there's not much we can startup */
+       if (conn == NULL)
+               return;
+
+       /* We will ignore the first call after initialization, as we
+        * don't want to autostart tracker-extract in this case (useful
+        * for debugging purposes).
+        */
+       if (watchdog->initializing) {
+               watchdog->initializing = FALSE;
+               return;
+       }
+
+       g_debug ("tracker-extract vanished, restarting after grace period.");
+
+       /* Close the name watch, so we'll create another one that will
+        * autostart the service if it not already running.
+        */
+       extract_watchdog_stop (watchdog);
+
+       /* Give a period of grace before restarting, so we allow replacing
+        * from eg. a terminal.
+        */
+       watchdog->timeout_id =
+               g_timeout_add_seconds (1, extract_watchdog_name_vanished_timeout,
+                                      watchdog);
+}
+
+static void
+extract_watchdog_start (TrackerExtractWatchdog *watchdog,
+                       gboolean                autostart)
+{
+       g_debug ("Setting up watch on tracker-extract (autostart: %s)",
+                autostart ? "yes" : "no");
+
+       watchdog->extractor_watchdog_id =
+               g_bus_watch_name (TRACKER_IPC_BUS,
+                                 TRACKER_MINER_DBUS_NAME_PREFIX "Extract",
+                                 (autostart ?
+                                  G_BUS_NAME_WATCHER_FLAGS_AUTO_START :
+                                  G_BUS_NAME_WATCHER_FLAGS_NONE),
+                                 NULL, extract_watchdog_name_vanished,
+                                 watchdog, NULL);
+}
+
+static void
+tracker_extract_watchdog_finalize (GObject *object)
+{
+       TrackerExtractWatchdog *watchdog = TRACKER_EXTRACT_WATCHDOG (object);
+
+       extract_watchdog_stop (watchdog);
+
+       if (watchdog->timeout_id) {
+               g_source_remove (watchdog->timeout_id);
+       }
+
+       G_OBJECT_CLASS (tracker_extract_watchdog_parent_class)->finalize (object);
+}
+
+static void
+tracker_extract_watchdog_class_init (TrackerExtractWatchdogClass *klass)
+{
+       GObjectClass *object_class = G_OBJECT_CLASS (klass);
+
+       object_class->finalize = tracker_extract_watchdog_finalize;
+}
+
+static void
+tracker_extract_watchdog_init (TrackerExtractWatchdog *watchdog)
+{
+       watchdog->initializing = TRUE;
+       extract_watchdog_start (watchdog, FALSE);
+}
+
+TrackerExtractWatchdog *
+tracker_extract_watchdog_new (void)
+{
+       return g_object_new (TRACKER_TYPE_EXTRACT_WATCHDOG,
+                            NULL);
+}
diff --git a/src/miners/fs/tracker-extract-watchdog.h b/src/miners/fs/tracker-extract-watchdog.h
new file mode 100644
index 0000000..1dab018
--- /dev/null
+++ b/src/miners/fs/tracker-extract-watchdog.h
@@ -0,0 +1,38 @@
+/*
+ * Copyright (C) 2016, Red Hat Inc.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the
+ * Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
+ * Boston, MA  02110-1301, USA.
+ */
+
+#ifndef __TRACKER_EXTRACT_WATCHDOG_H__
+#define __TRACKER_EXTRACT_WATCHDOG_H__
+
+#include <glib-object.h>
+
+G_BEGIN_DECLS
+
+#define TRACKER_TYPE_EXTRACT_WATCHDOG (tracker_extract_watchdog_get_type ())
+
+G_DECLARE_FINAL_TYPE (TrackerExtractWatchdog,
+                     tracker_extract_watchdog,
+                     TRACKER, EXTRACT_WATCHDOG,
+                     GObject)
+
+TrackerExtractWatchdog * tracker_extract_watchdog_new (void);
+
+G_END_DECLS
+
+#endif /* __TRACKER_EXTRACT_WATCHDOG_H__ */
diff --git a/src/miners/fs/tracker-miner-files.c b/src/miners/fs/tracker-miner-files.c
index e0cd48d..e2db5a7 100644
--- a/src/miners/fs/tracker-miner-files.c
+++ b/src/miners/fs/tracker-miner-files.c
@@ -44,6 +44,7 @@
 #include "tracker-miner-files.h"
 #include "tracker-config.h"
 #include "tracker-storage.h"
+#include "tracker-extract-watchdog.h"
 
 #define DISK_SPACE_CHECK_FREQUENCY 10
 #define SECONDS_PER_DAY 86400
@@ -65,6 +66,7 @@ struct ProcessFileData {
 struct TrackerMinerFilesPrivate {
        TrackerConfig *config;
        TrackerStorage *storage;
+       TrackerExtractWatchdog *extract_watchdog;
 
        GVolumeMonitor *volume_monitor;
 
@@ -552,6 +554,8 @@ miner_files_initable_init (GInitable     *initable,
 
        disk_space_check_start (mf);
 
+       mf->private->extract_watchdog = tracker_extract_watchdog_new ();
+
        return TRUE;
 }
 
@@ -604,6 +608,8 @@ miner_files_finalize (GObject *object)
        mf = TRACKER_MINER_FILES (object);
        priv = mf->private;
 
+       g_clear_object (&priv->extract_watchdog);
+
        if (priv->config) {
                g_signal_handlers_disconnect_by_func (priv->config,
                                                      low_disk_space_limit_cb,