[f-spot] Avoid busy waiting for database queries.

[Ruben Vermeersch <rubenv src gnome org>]

commit 89e6e0236bd615cc0327610e37d3e57e32f73524
Author: Michal Nánási <mic gnome ksp sk>
Date:   Fri May 14 19:14:13 2010 +0200

    Avoid busy waiting for database queries.
    
    Fixes BGO 614403 - Busy wait

 src/QueuedSqliteDatabase.cs |   10 +++++++++-
 1 files changed, 9 insertions(+), 1 deletions(-)
---
diff --git a/src/QueuedSqliteDatabase.cs b/src/QueuedSqliteDatabase.cs
index b8374af..86a387c 100644
--- a/src/QueuedSqliteDatabase.cs
+++ b/src/QueuedSqliteDatabase.cs
@@ -343,6 +343,7 @@ namespace Banshee.Database
         private int insert_id;
         private Exception execution_exception;
         private bool finished = false;
+        private Object finishedLock = new Object();
 
         private SqliteCommand command;
 
@@ -397,12 +398,19 @@ namespace Banshee.Database
             }
             command.Dispose();
             
+            Monitor.Enter(finishedLock);
             finished = true;
+            Monitor.Pulse(finishedLock);
+            Monitor.Exit(finishedLock);
         }
         
         public object WaitForResult()
         {
-            while(!finished);
+            Monitor.Enter(finishedLock);
+            while (!finished) {
+                Monitor.Wait(finishedLock);
+            };
+            Monitor.Exit(finishedLock);
             
             if(execution_exception != null) {
                 throw execution_exception;