add ParseFrom(ReadOnlySequence) methods

csharp/src/Google.Protobuf/MessageExtensions.cs

@@ -31,9 +31,11 @@
 #endregion
 
 using Google.Protobuf.Reflection;
+using System.Buffers;
 using System.Collections;
 using System.IO;
 using System.Linq;
+using System.Security;
 
 namespace Google.Protobuf
 {
@@ -248,6 +250,16 @@ namespace Google.Protobuf
             codedInput.CheckReadEndOfStreamTag();
         }
 
+        [SecuritySafeCritical]
+        internal static void MergeFrom(this IMessage message, ReadOnlySequence<byte> data, bool discardUnknownFields, ExtensionRegistry registry)
+        {
+            var ctx = new ParseContext(data);
+            ctx.DiscardUnknownFields = discardUnknownFields;
+            ctx.ExtensionRegistry = registry;
+            ParsingPrimitivesMessages.ReadRawMessage(ref ctx, message);
+            ParsingPrimitivesMessages.CheckReadEndOfStreamTag(ref ctx.state);
+        }
+
         internal static void MergeDelimitedFrom(this IMessage message, Stream input, bool discardUnknownFields, ExtensionRegistry registry)
         {
             ProtoPreconditions.CheckNotNull(message, "message");

csharp/src/Google.Protobuf/MessageParser.cs

@@ -31,7 +31,9 @@
 #endregion
 
 using System;
+using System.Buffers;
 using System.IO;
+using System.Security;
 
 namespace Google.Protobuf
 {
@@ -113,6 +115,19 @@ namespace Google.Protobuf
             return message;
         }
 
+        /// <summary>
+        /// Parses a message from the given sequence.
+        /// </summary>
+        /// <param name="data">The data to parse.</param>
+        /// <returns>The parsed message.</returns>
+        [SecuritySafeCritical]
+        public IMessage ParseFrom(ReadOnlySequence<byte> data)
+        {
+            IMessage message = factory();
+            message.MergeFrom(data, DiscardUnknownFields, Extensions);
+            return message;
+        }
+
         /// <summary>
         /// Parses a length-delimited message from the given stream.
         /// </summary>
@@ -287,6 +302,19 @@ namespace Google.Protobuf
             return message;
         }
 
+        /// <summary>
+        /// Parses a message from the given sequence.
+        /// </summary>
+        /// <param name="data">The data to parse.</param>
+        /// <returns>The parsed message.</returns>
+        [SecuritySafeCritical]
+        public new T ParseFrom(ReadOnlySequence<byte> data)
+        {
+            T message = factory();
+            message.MergeFrom(data, DiscardUnknownFields, Extensions);
+            return message;
+        }
+
         /// <summary>
         /// Parses a length-delimited message from the given stream.
         /// </summary>