Introduce a Parser property into MessageDescriptor, and populate it from generated types.

Generated code coming in next commit - in a subsequent PR I want to do a bit of renaming and redocumenting around this, in anticipation of DynamicMessage.

2 files changed, 19 insertions, 2 deletions

diff --git a/csharp/src/Google.Protobuf/Reflection/GeneratedCodeInfo.cs b/csharp/src/Google.Protobuf/Reflection/GeneratedCodeInfo.cs
index 8c52cd12..ff4ad0aa 100644
--- a/csharp/src/Google.Protobuf/Reflection/GeneratedCodeInfo.cs
+++ b/csharp/src/Google.Protobuf/Reflection/GeneratedCodeInfo.cs
@@ -18,6 +18,11 @@ namespace Google.Protobuf.Reflection
         public Type ClrType { get; private set; }
 
         /// <summary>
+        /// Irrelevant for file descriptors; the parser for message descriptors.
+        /// </summary>
+        public MessageParser Parser { get; private set; }
+
+        /// <summary>
         /// Irrelevant for file descriptors; the CLR property names (in message descriptor field order)
         /// for fields in the message for message descriptors.
         /// </summary>
@@ -46,11 +51,12 @@ namespace Google.Protobuf.Reflection
         /// Each array parameter may be null, to indicate a lack of values.
         /// The parameter order is designed to make it feasible to format the generated code readably.
         /// </summary>
-        public GeneratedCodeInfo(Type clrType, string[] propertyNames, string[] oneofNames, Type[] nestedEnums, GeneratedCodeInfo[] nestedTypes)
+        public GeneratedCodeInfo(Type clrType, MessageParser parser, string[] propertyNames, string[] oneofNames, Type[] nestedEnums, GeneratedCodeInfo[] nestedTypes)
         {
             NestedTypes = nestedTypes ?? EmptyCodeInfo;
             NestedEnums = nestedEnums ?? ReflectionUtil.EmptyTypes;
             ClrType = clrType;
+            Parser = parser;
             PropertyNames = propertyNames ?? EmptyNames;
             OneofNames = oneofNames ?? EmptyNames;
         }
@@ -59,7 +65,7 @@ namespace Google.Protobuf.Reflection
         /// Creates a GeneratedCodeInfo for a file descriptor, with only types and enums.
         /// </summary>
         public GeneratedCodeInfo(Type[] nestedEnums, GeneratedCodeInfo[] nestedTypes)
-            : this(null, null, null, nestedEnums, nestedTypes)
+            : this(null, null, null, null, nestedEnums, nestedTypes)
         {
         }
     }
diff --git a/csharp/src/Google.Protobuf/Reflection/MessageDescriptor.cs b/csharp/src/Google.Protobuf/Reflection/MessageDescriptor.cs
index e599998e..65040e42 100644
--- a/csharp/src/Google.Protobuf/Reflection/MessageDescriptor.cs
+++ b/csharp/src/Google.Protobuf/Reflection/MessageDescriptor.cs
@@ -67,11 +67,13 @@ namespace Google.Protobuf.Reflection
         private readonly IList<OneofDescriptor> oneofs;
         // CLR representation of the type described by this descriptor, if any.
         private readonly Type generatedType;
+        private readonly MessageParser parser;
         
         internal MessageDescriptor(DescriptorProto proto, FileDescriptor file, MessageDescriptor parent, int typeIndex, GeneratedCodeInfo generatedCodeInfo)
             : base(file, file.ComputeFullName(parent, proto.Name), typeIndex)
         {
             this.proto = proto;
+            parser = generatedCodeInfo == null ? null : generatedCodeInfo.Parser;
             generatedType = generatedCodeInfo == null ? null : generatedCodeInfo.ClrType;
 
             containingType = parent;
@@ -123,6 +125,15 @@ namespace Google.Protobuf.Reflection
         public Type GeneratedType { get { return generatedType; } }
 
         /// <summary>
+        /// A parser for this message type.
+        /// </summary>
+        /// <remarks>
+        /// As <see cref="MessageDescriptor"/> is not generic, this cannot be statically
+        /// typed to the relevant type, but if <see cref="GeneratedType"/> returns a non-null value, the parser returned
+        /// </remarks>
+        public MessageParser Parser { get { return parser; } }
+
+        /// <summary>
         /// Returns whether this message is one of the "well known types" which may have runtime/protoc support.
         /// </summary>
         internal bool IsWellKnownType