[tracker] libtracker-sparql: Fix deadlock when tracker is not available

[Jürg Billeter <juergbi src gnome org>]

commit dff0e6f4f006ce11a20fb9e8550232c8d59f5581
Author: Jürg Billeter <j bitron ch>
Date:   Wed Apr 13 10:39:02 2011 +0200

    libtracker-sparql: Fix deadlock when tracker is not available
    
    If a connection attempt failed, subsequent connection attempts
    deadlocked.

 src/libtracker-sparql-backend/tracker-backend.vala |   38 ++++++++++----------
 1 files changed, 19 insertions(+), 19 deletions(-)
---
diff --git a/src/libtracker-sparql-backend/tracker-backend.vala b/src/libtracker-sparql-backend/tracker-backend.vala
index 110a203..76eb956 100644
--- a/src/libtracker-sparql-backend/tracker-backend.vala
+++ b/src/libtracker-sparql-backend/tracker-backend.vala
@@ -195,31 +195,31 @@ class Tracker.Sparql.Backend : Connection {
 	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
-		var result = singleton;
-		if (result != null) {
-			assert (direct_only == is_direct_only);
-			door.unlock ();
-			return result;
-		}
-
-		log_init ();
+		try {
+			// assign to owned variable to ensure it doesn't get freed between check and return
+			var result = singleton;
+			if (result != null) {
+				assert (direct_only == is_direct_only);
+				return result;
+			}
 
-		direct_only = is_direct_only;
+			log_init ();
 
-		result = new Tracker.Sparql.Backend ();
+			direct_only = is_direct_only;
 
-		if (cancellable != null && cancellable.is_cancelled ()) {
-			door.unlock ();
-			throw new IOError.CANCELLED ("Operation was cancelled");
-		}
+			result = new Tracker.Sparql.Backend ();
 
-		singleton = result;
-		result.add_weak_pointer ((void**) (&singleton));
+			if (cancellable != null && cancellable.is_cancelled ()) {
+				throw new IOError.CANCELLED ("Operation was cancelled");
+			}
 
-		door.unlock ();
+			singleton = result;
+			result.add_weak_pointer ((void**) (&singleton));
 
-		return singleton;
+			return singleton;
+		} finally {
+			door.unlock ();
+		}
 	}
 
 	public static new Connection get_internal (bool is_direct_only = false, Cancellable? cancellable = null) throws Sparql.Error, IOError, DBusError, SpawnError {