[tracker] libtracker-data: Use internal mutex for TrackerDBManager (de)init

[Carlos Garnacho <carlosg src gnome org>]

commit b7c138a08c578061f99db2c1fc712a6c2db78180
Author: Carlos Garnacho <carlosg gnome org>
Date:   Sat Nov 5 19:46:53 2016 +0100

    libtracker-data: Use internal mutex for TrackerDBManager (de)init
    
    There's no reason to handle locking externally, and this is not a frequent
    enough operation to care about thread contention times in eg.
    tracker-store, so just add an internal mutex protecting initialization.

 src/libtracker-data/tracker-db-manager.c |   64 ++++++++++++++++++++++++------
 1 files changed, 51 insertions(+), 13 deletions(-)
---
diff --git a/src/libtracker-data/tracker-db-manager.c b/src/libtracker-data/tracker-db-manager.c
index 44c2321..be0f2d4 100644
--- a/src/libtracker-data/tracker-db-manager.c
+++ b/src/libtracker-data/tracker-db-manager.c
@@ -168,6 +168,9 @@ static GMutex                global_mutex;
 
 static TrackerDBInterface   *global_iface;
 
+/* mutex protecting DB manager initialization/shutdown */
+static GMutex                init_mutex;
+
 static const gchar *
 location_to_directory (TrackerDBLocation location)
 {
@@ -847,17 +850,17 @@ perform_recreate (gboolean *first_time, GError **error)
        }
 }
 
-gboolean
-tracker_db_manager_init (TrackerDBManagerFlags   flags,
-                         gboolean               *first_time,
-                         gboolean                restoring_backup,
-                         gboolean                shared_cache,
-                         guint                   select_cache_size,
-                         guint                   update_cache_size,
-                         TrackerBusyCallback     busy_callback,
-                         gpointer                busy_user_data,
-                         const gchar            *busy_operation,
-                         GError                **error)
+static gboolean
+db_manager_init_unlocked (TrackerDBManagerFlags   flags,
+                          gboolean               *first_time,
+                          gboolean                restoring_backup,
+                          gboolean                shared_cache,
+                          guint                   select_cache_size,
+                          guint                   update_cache_size,
+                          TrackerBusyCallback     busy_callback,
+                          gpointer                busy_user_data,
+                          const gchar            *busy_operation,
+                          GError                **error)
 {
        GType etype;
        TrackerDBVersion version;
@@ -1245,8 +1248,35 @@ tracker_db_manager_init (TrackerDBManagerFlags   flags,
        return TRUE;
 }
 
-void
-tracker_db_manager_shutdown (void)
+gboolean
+tracker_db_manager_init (TrackerDBManagerFlags   flags,
+                         gboolean               *first_time,
+                         gboolean                restoring_backup,
+                         gboolean                shared_cache,
+                         guint                   select_cache_size,
+                         guint                   update_cache_size,
+                         TrackerBusyCallback     busy_callback,
+                         gpointer                busy_user_data,
+                         const gchar            *busy_operation,
+                         GError                **error)
+{
+       gboolean retval;
+
+       g_mutex_lock (&init_mutex);
+
+       retval = db_manager_init_unlocked (flags, first_time, restoring_backup,
+                                          shared_cache,
+                                          select_cache_size, update_cache_size,
+                                          busy_callback, busy_user_data,
+                                          busy_operation, error);
+
+       g_mutex_unlock (&init_mutex);
+
+       return retval;
+}
+
+static void
+db_manager_shutdown_unlocked (void)
 {
        guint i;
 
@@ -1305,6 +1335,14 @@ tracker_db_manager_shutdown (void)
 }
 
 void
+tracker_db_manager_shutdown (void)
+{
+       g_mutex_lock (&init_mutex);
+       db_manager_shutdown_unlocked ();
+       g_mutex_unlock (&init_mutex);
+}
+
+void
 tracker_db_manager_remove_all (gboolean rm_journal)
 {
        g_return_if_fail (initialized != FALSE);