Move payload deserialisation out of handlers.

This is so the common JsonSerializerSettings can be used by the calling
code.

NOTE: This code is currently non-functional - handlers have been
modified to take an Object instead of a JObject but the calling code
does not yet perform deserialisation.

Author: tintoy

src/Client/Handlers/DelegateEmptyNotificationHandler.cs

@@ -32,6 +32,11 @@ public DelegateEmptyNotificationHandler(string method, NotificationHandler handl
         /// </summary>
         public NotificationHandler Handler { get; }
 
+        /// <summary>
+        ///     The expected CLR type of the notification body (<c>null</c>, since the handler does not use the request body).
+        /// </summary>
+        public override Type BodyType => null;
+
         /// <summary>
         ///     Invoke the handler.
         /// </summary>

src/Client/Handlers/DelegateHandler.cs

@@ -26,5 +26,10 @@ protected DelegateHandler(string method)
         ///     The name of the method handled by the handler.
         /// </summary>
         public string Method { get; }
+
+        /// <summary>
+        ///     The expected CLR type of the request / notification body (if any; <c>null</c> if the handler does not use the request body).
+        /// </summary>
+        public abstract Type BodyType { get; }
     }
 }

src/Client/Handlers/DelegateNotificationHandler.cs

@@ -38,6 +38,11 @@ public DelegateNotificationHandler(string method, NotificationHandler<TNotificat
         /// </summary>
         public NotificationHandler<TNotification> Handler { get; }
 
+        /// <summary>
+        ///     The expected CLR type of the notification body.
+        /// </summary>
+        public override Type BodyType => typeof(TNotification);
+
         /// <summary>
         ///     Invoke the handler.
         /// </summary>
@@ -47,12 +52,12 @@ public DelegateNotificationHandler(string method, NotificationHandler<TNotificat
         /// <returns>
         ///     A <see cref="Task"/> representing the operation.
         /// </returns>
-        public async Task Invoke(JObject notification)
+        public async Task Invoke(object notification)
         {
             await Task.Yield();
 
             Handler(
-                notification != null ? notification.ToObject<TNotification>(Serializer.Instance.JsonSerializer /* Fix me: this is ugly */) : default(TNotification)
+                (TNotification)notification
             );
         }
     }

src/Client/Handlers/DelegateRequestHandler.cs

@@ -39,6 +39,11 @@ public DelegateRequestHandler(string method, RequestHandler<TRequest> handler)
         /// </summary>
         public RequestHandler<TRequest> Handler { get; }
 
+        /// <summary>
+        ///     The expected CLR type of the request body.
+        /// </summary>
+        public override Type BodyType => typeof(TRequest);
+
         /// <summary>
         ///     Invoke the handler.
         /// </summary>
@@ -51,10 +56,10 @@ public DelegateRequestHandler(string method, RequestHandler<TRequest> handler)
         /// <returns>
         ///     A <see cref="Task{TResult}"/> representing the operation.
         /// </returns>
-        public async Task<object> Invoke(JObject request, CancellationToken cancellationToken)
+        public async Task<object> Invoke(object request, CancellationToken cancellationToken)
         {
             await Handler(
-                request != null ? request.ToObject<TRequest>(Serializer.Instance.JsonSerializer /* Fix me: this is ugly */) : default(TRequest),
+                (TRequest)request,
                 cancellationToken
             );
 

src/Client/Handlers/DelegateRequestResponseHandler.cs

@@ -42,6 +42,11 @@ public DelegateRequestResponseHandler(string method, RequestHandler<TRequest, TR
         /// </summary>
         public RequestHandler<TRequest, TResponse> Handler { get; }
 
+        /// <summary>
+        ///     The expected CLR type of the request body.
+        /// </summary>
+        public override Type BodyType => typeof(TRequest);
+
         /// <summary>
         ///     Invoke the handler.
         /// </summary>
@@ -54,10 +59,10 @@ public DelegateRequestResponseHandler(string method, RequestHandler<TRequest, TR
         /// <returns>
         ///     A <see cref="Task{TResult}"/> representing the operation.
         /// </returns>
-        public async Task<object> Invoke(JObject request, CancellationToken cancellationToken)
+        public async Task<object> Invoke(object request, CancellationToken cancellationToken)
         {
             return await Handler(
-                request != null ? request.ToObject<TRequest>(Serializer.Instance.JsonSerializer /* Fix me: this is ugly */) : default(TRequest),
+                (TRequest)request,
                 cancellationToken
             );
         }

src/Client/Handlers/DynamicRegistrationHandler.cs

@@ -1,3 +1,4 @@
+using System;
 using System.Threading;
 using System.Threading.Tasks;
 using Newtonsoft.Json.Linq;
@@ -31,6 +32,11 @@ public DynamicRegistrationHandler()
         /// </summary>
         public string Method => "client/registerCapability";
 
+        /// <summary>
+        ///     The expected CLR type of the request / notification body (if any; <c>null</c> if the handler does not use the request body).
+        /// </summary>
+        public Type BodyType => null;
+
         /// <summary>
         ///     Invoke the handler.
         /// </summary>
@@ -43,7 +49,7 @@ public DynamicRegistrationHandler()
         /// <returns>
         ///     A <see cref="Task{TResult}"/> representing the operation.
         /// </returns>
-        public Task<object> Invoke(JObject request, CancellationToken cancellationToken)
+        public Task<object> Invoke(object request, CancellationToken cancellationToken)
         {
             // For now, we don't really support dynamic registration but OmniSharp's implementation sends a request even when dynamic registrations are not supported.
 

src/Client/Handlers/IHandler.cs

@@ -1,4 +1,6 @@
-namespace OmniSharp.Extensions.LanguageServer.Client.Handlers
+using System;
+
+namespace OmniSharp.Extensions.LanguageServer.Client.Handlers
 {
     /// <summary>
     ///     Represents a client-side message handler.
@@ -9,5 +11,10 @@ public interface IHandler
         ///     The name of the method handled by the handler.
         /// </summary>
         string Method { get; }
+
+        /// <summary>
+        ///     The expected CLR type of the request / notification body (if any; <c>null</c> if the handler does not use the request body).
+        /// </summary>
+        Type BodyType { get; }
     }
 }

src/Client/Handlers/IInvokeNotificationHandler.cs

@@ -18,6 +18,6 @@ public interface IInvokeNotificationHandler
         /// <returns>
         ///     A <see cref="Task"/> representing the operation.
         /// </returns>
-        Task Invoke(JObject notification);
+        Task Invoke(object notification);
     }
 }

src/Client/Handlers/IInvokeRequestHandler.cs

@@ -22,6 +22,6 @@ public interface IInvokeRequestHandler
         /// <returns>
         ///     A <see cref="Task{TResult}"/> representing the operation.
         /// </returns>
-        Task<object> Invoke(JObject request, CancellationToken cancellationToken);
+        Task<object> Invoke(object request, CancellationToken cancellationToken);
     }
 }

src/Client/Handlers/JsonRpcEmptyNotificationHandler.cs

@@ -33,6 +33,11 @@ public JsonRpcEmptyNotificationHandler(string method, INotificationHandler handl
         /// </summary>
         public INotificationHandler Handler { get; }
 
+        /// <summary>
+        ///     The expected CLR type of the notification body (<c>null</c>, since the handler does not use the request body).
+        /// </summary>
+        public override Type BodyType => null;
+
         /// <summary>
         ///     Invoke the handler.
         /// </summary>

src/Client/Handlers/JsonRpcHandler.cs

@@ -27,5 +27,10 @@ protected JsonRpcHandler(string method)
         ///     The name of the method handled by the handler.
         /// </summary>
         public string Method { get; }
+
+        /// <summary>
+        ///     The expected CLR type of the request / notification body (if any; <c>null</c> if the handler does not use the request body).
+        /// </summary>
+        public abstract Type BodyType { get; }
     }
 }

src/Client/Handlers/JsonRpcNotificationHandler.cs

@@ -1,6 +1,5 @@
 using System;
 using System.Threading.Tasks;
-using Newtonsoft.Json.Linq;
 using OmniSharp.Extensions.JsonRpc;
 using OmniSharp.Extensions.LanguageServer.Protocol;
 using OmniSharp.Extensions.LanguageServer.Protocol.Serialization;
@@ -39,6 +38,11 @@ public JsonRpcNotificationHandler(string method, INotificationHandler<TNotificat
         /// </summary>
         public INotificationHandler<TNotification> Handler { get; }
 
+        /// <summary>
+        ///     The expected CLR type of the notification body.
+        /// </summary>
+        public override Type BodyType => typeof(TNotification);
+
         /// <summary>
         ///     Invoke the handler.
         /// </summary>
@@ -48,8 +52,8 @@ public JsonRpcNotificationHandler(string method, INotificationHandler<TNotificat
         /// <returns>
         ///     A <see cref="Task"/> representing the operation.
         /// </returns>
-        public Task Invoke(JObject notification) => Handler.Handle(
-            notification != null ? notification.ToObject<TNotification>(Serializer.Instance.JsonSerializer /* Fix me: this is ugly */) : default(TNotification)
+        public Task Invoke(object notification) => Handler.Handle(
+            (TNotification)notification
         );
     }
 }