First cut at new layout

1 files changed, 56 insertions, 0 deletions

diff --git a/src/ProtocolBuffers/Collections/Lists.cs b/src/ProtocolBuffers/Collections/Lists.cs
new file mode 100644
index 00000000..b1b6b122
--- /dev/null
+++ b/src/ProtocolBuffers/Collections/Lists.cs
@@ -0,0 +1,56 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.
+// http://code.google.com/p/protobuf/
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+using System.Collections.Generic;
+using System.Collections.ObjectModel;
+
+namespace Google.ProtocolBuffers.Collections {
+
+  /// <summary>
+  /// Utility non-generic class for calling into Lists{T} using type inference.
+  /// </summary>
+  public static class Lists {
+
+    /// <summary>
+    /// Returns a read-only view of the specified list.
+    /// </summary>
+    public static IList<T> AsReadOnly<T>(IList<T> list) {
+      return Lists<T>.AsReadOnly(list);
+    }
+  }
+
+  /// <summary>
+  /// Utility class for dealing with lists.
+  /// </summary>
+  public static class Lists<T> {
+
+    static readonly ReadOnlyCollection<T> empty = new ReadOnlyCollection<T>(new T[0]);
+
+    /// <summary>
+    /// Returns an immutable empty list.
+    /// </summary>
+    public static ReadOnlyCollection<T> Empty {
+      get { return empty; }
+    }
+
+    /// <summary>
+    /// Returns either the original reference if it's already read-only,
+    /// or a new ReadOnlyCollection wrapping the original list.
+    /// </summary>
+    public static IList<T> AsReadOnly(IList<T> list) {
+      return list.IsReadOnly ? list : new ReadOnlyCollection<T>(list);
+    }
+  }
+}