[tracker/wip/sam/private-store: 1/3] libtracker-sparql: Move log initialization out of TrackerBackend class

[Sam Thursfield <sthursfield src gnome org>]

commit 0dbe85dbf986f4ed46321231322b956d4ccba19a
Author: Sam Thursfield <sam afuera me uk>
Date:   Thu Jun 23 23:12:43 2016 +0100

    libtracker-sparql: Move log initialization out of TrackerBackend class
    
    This allows me to have two backend class types,
    TrackerSessionwideBackend and TrackerPrivateBackend, and have either of them
    init logging when first called.

 src/libtracker-sparql-backend/tracker-backend.vala |  109 ++++++++++----------
 1 files changed, 54 insertions(+), 55 deletions(-)
---
diff --git a/src/libtracker-sparql-backend/tracker-backend.vala 
b/src/libtracker-sparql-backend/tracker-backend.vala
index df0cf6c..6f1219d 100644
--- a/src/libtracker-sparql-backend/tracker-backend.vala
+++ b/src/libtracker-sparql-backend/tracker-backend.vala
@@ -17,6 +17,60 @@
  * Boston, MA  02110-1301, USA.
  */
 
+static size_t log_initialized = false;
+
+static void log_init () {
+       if (GLib.Once.init_enter(&log_initialized)) {
+               // Avoid debug messages
+               int verbosity = 0;
+               string env_verbosity = Environment.get_variable ("TRACKER_VERBOSITY");
+               if (env_verbosity != null)
+                       verbosity = int.parse (env_verbosity);
+
+               LogLevelFlags remove_levels = 0;
+
+               // If we have debug enabled, we imply G_MESSAGES_DEBUG or we
+               // see nothing, this came in since GLib 2.32.
+               if (verbosity > 2)
+                       Environment.set_variable ("G_MESSAGES_DEBUG", "all", true);
+
+               switch (verbosity) {
+               // Log level 3: EVERYTHING
+               case 3:
+                       break;
+
+               // Log level 2: CRITICAL/ERROR/WARNING/INFO/MESSAGE only
+               case 2:
+                       remove_levels = LogLevelFlags.LEVEL_DEBUG;
+                       break;
+
+               // Log level 1: CRITICAL/ERROR/WARNING/INFO only
+               case 1:
+                       remove_levels = LogLevelFlags.LEVEL_DEBUG |
+                                     LogLevelFlags.LEVEL_MESSAGE;
+                       break;
+
+               // Log level 0: CRITICAL/ERROR/WARNING only (default)
+               default:
+               case 0:
+                       remove_levels = LogLevelFlags.LEVEL_DEBUG |
+                                     LogLevelFlags.LEVEL_MESSAGE |
+                                     LogLevelFlags.LEVEL_INFO;
+                       break;
+               }
+
+               if (remove_levels != 0) {
+                       GLib.Log.set_handler ("Tracker", remove_levels, remove_log_handler);
+               }
+
+               GLib.Once.init_leave (&log_initialized, true);
+       }
+}
+
+static void remove_log_handler (string? log_domain, LogLevelFlags log_level, string message) {
+       /* do nothing */
+}
+
 class Tracker.Sparql.Backend : Connection {
        bool initialized;
        Tracker.Sparql.Connection direct = null;
@@ -228,7 +282,6 @@ class Tracker.Sparql.Backend : Connection {
        }
 
        static weak Connection? singleton;
-       static bool log_initialized;
        static Mutex door;
 
        static new Connection get (Cancellable? cancellable = null) throws Sparql.Error, IOError, DBusError, 
SpawnError {
@@ -338,60 +391,6 @@ class Tracker.Sparql.Backend : Connection {
                        return result;
                }
        }
-
-       private static void log_init () {
-               if (log_initialized) {
-                       return;
-               }
-
-               log_initialized = true;
-
-               // Avoid debug messages
-               int verbosity = 0;
-               string env_verbosity = Environment.get_variable ("TRACKER_VERBOSITY");
-               if (env_verbosity != null)
-                       verbosity = int.parse (env_verbosity);
-
-               LogLevelFlags remove_levels = 0;
-
-               // If we have debug enabled, we imply G_MESSAGES_DEBUG or we
-               // see nothing, this came in since GLib 2.32.
-               if (verbosity > 2)
-                       Environment.set_variable ("G_MESSAGES_DEBUG", "all", true);
-
-               switch (verbosity) {
-               // Log level 3: EVERYTHING
-               case 3:
-                       break;
-
-               // Log level 2: CRITICAL/ERROR/WARNING/INFO/MESSAGE only
-               case 2:
-                       remove_levels = LogLevelFlags.LEVEL_DEBUG;
-                       break;
-
-               // Log level 1: CRITICAL/ERROR/WARNING/INFO only
-               case 1:
-                       remove_levels = LogLevelFlags.LEVEL_DEBUG |
-                                     LogLevelFlags.LEVEL_MESSAGE;
-                       break;
-
-               // Log level 0: CRITICAL/ERROR/WARNING only (default)
-               default:
-               case 0:
-                       remove_levels = LogLevelFlags.LEVEL_DEBUG |
-                                     LogLevelFlags.LEVEL_MESSAGE |
-                                     LogLevelFlags.LEVEL_INFO;
-                       break;
-               }
-
-               if (remove_levels != 0) {
-                       GLib.Log.set_handler ("Tracker", remove_levels, remove_log_handler);
-               }
-       }
-
-       private static void remove_log_handler (string? log_domain, LogLevelFlags log_level, string message) {
-               /* do nothing */
-       }
 }
 
 public async static Tracker.Sparql.Connection tracker_sparql_connection_get_async (Cancellable? cancellable 
= null) throws Tracker.Sparql.Error, IOError, DBusError, SpawnError {