[tracker/tracker-0.10] libtracker-sparql: Use separate thread for sync init if necessary

[Martyn James Russell <mr src gnome org>]

commit 62c9affdb21953d89a739932c5b1847f817a585b
Author: Jürg Billeter <j bitron ch>
Date:   Thu Apr 7 12:35:47 2011 +0200

    libtracker-sparql: Use separate thread for sync init if necessary
    
    tracker_locale_init must run with the thread-default context set to the
    global default context. As pushing a new thread-default context
    requires the current thread to be the owner of the passed context, we
    cannot always push the global default context as a thread-default
    context.
    
    This commit uses a threadpool job in the case that sync initialization
    is requestesd with the thread-default context not set to the global
    default context.

 src/libtracker-sparql-backend/tracker-backend.vala |   29 ++++++++++++++++++-
 1 files changed, 27 insertions(+), 2 deletions(-)
---
diff --git a/src/libtracker-sparql-backend/tracker-backend.vala b/src/libtracker-sparql-backend/tracker-backend.vala
index d68b2c6..18bb9a3 100644
--- a/src/libtracker-sparql-backend/tracker-backend.vala
+++ b/src/libtracker-sparql-backend/tracker-backend.vala
@@ -199,7 +199,7 @@ class Tracker.Sparql.Backend : Connection {
 	static bool log_initialized;
 	static StaticMutex door;
 
-	public static new Connection get_internal (bool is_direct_only = false, Cancellable? cancellable = null) throws Sparql.Error, IOError, DBusError, SpawnError {
+	static new Connection get (bool is_direct_only = false, Cancellable? cancellable = null) throws Sparql.Error, IOError, DBusError, SpawnError {
 		door.lock ();
 
 		// assign to owned variable to ensure it doesn't get freed between unlock and return
@@ -230,6 +230,31 @@ class Tracker.Sparql.Backend : Connection {
 		return singleton;
 	}
 
+	public static new Connection get_internal (bool is_direct_only = false, Cancellable? cancellable = null) throws Sparql.Error, IOError, DBusError, SpawnError {
+		if (MainContext.get_thread_default () == null) {
+			// ok to initialize without extra thread
+			return get (is_direct_only, cancellable);
+		}
+
+		// run with separate main context to be able to wait for async method
+		var context = new MainContext ();
+		var loop = new MainLoop (context);
+		AsyncResult async_result = null;
+
+		context.push_thread_default ();
+
+		get_internal_async.begin (is_direct_only, cancellable, (obj, res) => {
+			async_result = res;
+			loop.quit ();
+		});
+
+		loop.run ();
+
+		context.pop_thread_default ();
+
+		return get_internal_async.end (async_result);
+	}
+
 	public async static new Connection get_internal_async (bool is_direct_only = false, Cancellable? cancellable = null) throws Sparql.Error, IOError, DBusError, SpawnError {
 		// fast path: avoid extra thread if connection is already available
 		if (door.trylock ()) {
@@ -254,7 +279,7 @@ class Tracker.Sparql.Backend : Connection {
 
 		g_io_scheduler_push_job (job => {
 			try {
-				result = get_internal (is_direct_only, cancellable);
+				result = get (is_direct_only, cancellable);
 			} catch (IOError e_io) {
 				io_error = e_io;
 			} catch (Sparql.Error e_spql) {