Implement freezing for messages and repeated fields.

Fixes issue #523.

1 files changed, 60 insertions, 0 deletions

diff --git a/csharp/src/ProtocolBuffers/Freezable.cs b/csharp/src/ProtocolBuffers/Freezable.cs
new file mode 100644
index 00000000..40b4398a
--- /dev/null
+++ b/csharp/src/ProtocolBuffers/Freezable.cs
@@ -0,0 +1,60 @@
+#region Copyright notice and license
+
+// Protocol Buffers - Google's data interchange format
+// Copyright 2015 Google Inc.  All rights reserved.
+// http://github.com/google/protobuf
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#endregion
+
+using System;
+
+namespace Google.Protobuf
+{
+    /// <summary>
+    /// Extension methods for <see cref="IFreezable"/> types.
+    /// </summary>
+    public static class Freezable
+    {
+        /// <summary>
+        /// Throws an <see cref="InvalidOperationException"/> if <paramref name="target"/>
+        /// is frozen.
+        /// </summary>
+        /// <remarks>
+        /// This is a convenience methods that freezable types can call before all
+        /// mutations, to protect frozen objects.
+        /// </remarks>
+        public static void CheckMutable(this IFreezable target)
+        {
+            if (target.IsFrozen)
+            {
+                throw new InvalidOperationException("Attempt to mutate frozen object");
+            }
+        }
+    }
+}