tracker-store: Protect ready writeback events with mutex

Just like with ready GraphUpdated events, this will be potentially accessed
by both the thread performing updates, and the thread doing the DBus
dispatching and signaling.

Just like there, the chances of contention are rather low, since emission
is checked just once per second by default.

1 files changed, 11 insertions, 0 deletions

diff --git a/src/tracker-store/tracker-writeback.c b/src/tracker-store/tracker-writeback.c
index 5bba19020..1edc3e2dd 100644
--- a/src/tracker-store/tracker-writeback.c
+++ b/src/tracker-store/tracker-writeback.c
@@ -27,8 +27,12 @@
 #include "tracker-writeback.h"
 
 typedef struct {
+	/* Accessed by updates thread */
 	GHashTable *allowances;
 	GHashTable *pending_events;
+
+	/* Accessed by both updates and dbus threads */
+	GMutex mutex;
 	GHashTable *ready_events;
 } WritebackPrivate;
 
@@ -119,8 +123,10 @@ tracker_writeback_get_ready (void)
 
 	g_return_val_if_fail (private != NULL, NULL);
 
+	g_mutex_lock (&private->mutex);
 	events = private->ready_events;
 	private->ready_events = NULL;
+	g_mutex_unlock (&private->mutex);
 
 	return events;
 }
@@ -150,6 +156,7 @@ tracker_writeback_init (TrackerDataManager                *data_manager,
 	g_return_if_fail (private == NULL);
 
 	private = g_new0 (WritebackPrivate, 1);
+	g_mutex_init (&private->mutex);
 
 	private->allowances = g_hash_table_new_full (g_direct_hash,
 	                                             g_direct_equal,
@@ -196,6 +203,8 @@ tracker_writeback_transact (void)
 	if (!private->pending_events)
 		return;
 
+	g_mutex_lock (&private->mutex);
+
 	if (!private->ready_events) {
 		private->ready_events = g_hash_table_new_full (g_direct_hash, g_direct_equal,
 		                                               (GDestroyNotify) NULL,
@@ -208,6 +217,8 @@ tracker_writeback_transact (void)
 		g_hash_table_insert (private->ready_events, key, value);
 		g_hash_table_iter_remove (&iter);
 	}
+
+	g_mutex_unlock (&private->mutex);
 }
 
 void