[PLinq] Add a more specialized visitor object for checking query ordering.

mcs/class/System.Core/System.Linq.Parallel/ParallelExecuter.cs

@@ -61,11 +61,12 @@ namespace System.Linq.Parallel
 			return linked.Token;
 		}
 
-		// TODO: replace the CheckQuery call with a custom visitor that stops after the
-		// first encountered order guard
 		internal static bool IsOrdered<TSource> (this QueryBaseNode<TSource> source)
 		{
-			return CheckQuery (source).BehindOrderGuard.Value;
+			QueryIsOrderedVisitor visitor = new QueryIsOrderedVisitor ();
+			source.Visit (visitor);
+
+			return visitor.BehindOrderGuard;
 		}
 
 		internal static int GetBestWorkerNumber ()

mcs/class/System.Core/System.Linq.Parallel/QueryIsOrderedVisitor.cs

@@ -0,0 +1,83 @@
+//
+// QueryIsOrderedVisitor.cs
+//
+// Author:
+//       Jérémie "Garuma" Laval <[email protected]>
+//
+// Copyright (c) 2010 Jérémie "Garuma" Laval
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+// THE SOFTWARE.
+
+#if NET_4_0
+using System;
+using System.Threading;
+using System.Linq.Parallel.QueryNodes;
+
+namespace System.Linq.Parallel
+{
+	internal class QueryIsOrderedVisitor : INodeVisitor
+	{
+		internal bool BehindOrderGuard {
+			get;
+			private set;
+		}
+
+		#region INodeVisitor implementation
+		public void Visit<T> (QueryBaseNode<T> node)
+		{
+
+		}
+
+		public void Visit<U, V> (QueryChildNode<U, V> node)
+		{
+			node.Parent.Visit (this);
+		}
+
+		public void Visit<T> (QueryOptionNode<T> node)
+		{
+			Visit<T, T> ((QueryChildNode<T, T>)node);
+		}
+
+		public void Visit<T> (QueryStartNode<T> node)
+		{
+		}
+
+		public void Visit<T, TParent> (QueryStreamNode<T, TParent> node)
+		{
+			Visit<T, TParent> ((QueryChildNode<T, TParent>)node);
+		}
+
+		public void Visit<T> (QueryOrderGuardNode<T> node)
+		{
+			BehindOrderGuard = node.EnsureOrder;
+		}
+
+		public void Visit<TFirst, TSecond, TResult> (QueryMuxNode<TFirst, TSecond, TResult> node)
+		{
+			Visit<TResult, TFirst> ((QueryChildNode<TResult, TFirst>)node);
+		}
+
+		public void Visit<T> (QueryHeadWorkerNode<T> node)
+		{
+			Visit<T, T> ((QueryStreamNode<T, T>)node);
+		}
+		#endregion
+	}
+}
+#endif

mcs/class/System.Core/net_4_0_System.Core.dll.sources

@@ -252,6 +252,7 @@ System.Linq.Parallel.QueryNodes/QueryJoinNode.cs
 System.Linq.Parallel/INodeVisitor.cs
 System.Linq.Parallel/IVisitableNode.cs
 System.Linq.Parallel/QueryCheckerVisitor.cs
+System.Linq.Parallel/QueryIsOrderedVisitor.cs
 System.Linq.Parallel/QueryOptions.cs
 ../corlib/System.Collections.Concurrent/Partitioners/EnumerablePartitioner.cs
 ../corlib/System.Collections.Concurrent/ConcurrentSkipList.cs