Remove Lock from ListBasedLoadBalancePolicy in benefit of ReaderWriterLockSlim

castleproject#565

Author: generik0

src/Castle.Facilities.WcfIntegration/Service/Discovery/LoadBalance/ListBasedLoadBalancePolicy.cs

@@ -17,6 +17,8 @@ namespace Castle.Facilities.WcfIntegration
 	using System;
 	using System.Collections.Generic;
 	using System.ServiceModel.Discovery;
+	using System.Threading;
+
 	using Castle.Core.Internal;
 
 	public delegate bool PolicyMembership(EndpointDiscoveryMetadata endpoint);
@@ -25,7 +27,7 @@ public abstract class ListBasedLoadBalancePolicy : ILoadBalancePolicy
 	{
 		private readonly PolicyMembership membership;
 		private readonly List<EndpointDiscoveryMetadata> targets;
-		private readonly Lock @lock = Lock.Create();
+		private readonly ReaderWriterLockSlim @lock = new ReaderWriterLockSlim();
 
 		protected ListBasedLoadBalancePolicy(PolicyMembership membership)
 		{
@@ -50,25 +52,29 @@ public bool RegisterTarget(EndpointDiscoveryMetadata target)
 		{
 			if (membership(target) == false)
 				return false;
-
-			using (@lock.ForWriting())
+			@lock.EnterWriteLock();
+			try
 			{
 				var index = FindTargetIndex(target);
 				if (index >= 0)
 					targets[index] = target;
 				else
 					targets.Add(target);
 			}
-
-			return true;
+			finally
+			{
+				@lock.ExitWriteLock();
+			}
+			return true; 
 		}
 
 		public bool RemoveTarget(EndpointDiscoveryMetadata target)
 		{
 			if (membership(target) == false)
 				return false;
 
-			using (@lock.ForWriting())
+			@lock.EnterWriteLock();
+			try
 			{
 				var index = FindTargetIndex(target);
 				if (index >= 0)
@@ -77,16 +83,24 @@ public bool RemoveTarget(EndpointDiscoveryMetadata target)
 					return true;
 				}
 			}
-
+			finally
+			{
+				@lock.ExitWriteLock();
+			}
 			return false;
 		}
 
 		public void CollectTargets(ICollection<EndpointDiscoveryMetadata> collected)
 		{
-			using (@lock.ForReading())
+			@lock.EnterReadLock();
+			try
 			{
 				targets.ForEach(collected.Add);
 			}
+			finally
+			{
+				@lock.ExitReadLock();
+			}
 		}
 
 		private int FindTargetIndex(EndpointDiscoveryMetadata target)
@@ -128,21 +142,31 @@ public void ReadList(Func<IList<EndpointDiscoveryMetadata>, EndpointDiscoveryMet
 			{
 				if (readList != null)
 				{
-					using (policy.@lock.ForReading())
+					policy.@lock.EnterReadLock();
+					try
 					{
 						selectedEndpoint = readList(policy.targets.AsReadOnly());
 					}
+					finally
+					{
+						policy.@lock.ExitReadLock();
+					}
 				}
 			}
 
 			public void ModifyList(Func<IList<EndpointDiscoveryMetadata>, EndpointDiscoveryMetadata> modifyList)
 			{
 				if (modifyList != null)
 				{
-					using (policy.@lock.ForWriting())
+					policy.@lock.EnterWriteLock();
+					try
 					{
 						selectedEndpoint = modifyList(policy.targets);
 					}
+					finally
+					{
+						policy.@lock.EnterWriteLock();
+					}
 				}
 			}
 		}