Merge pull request #76 from OmniSharp/preprocessing

Added preprocessing for notifications

Author: david-driscoll

src/Server/LspRequestRouter.cs

@@ -93,6 +93,15 @@ public async Task RouteNotification(IHandlerDescriptor descriptor, Notification
                         {
                             _logger.LogDebug("Converting params for Notification {Method} to {Type}", notification.Method, descriptor.Params.FullName);
                             var @params = notification.Params.ToObject(descriptor.Params, _serializer.JsonSerializer);
+
+                            var lspDescriptor = descriptor as ILspHandlerDescriptor;
+
+                            foreach (var preProcessor in _routeMatchers.ForHandlerPreProcessorMatcher()
+                                .SelectMany(strat => strat.FindPreProcessor(lspDescriptor, @params)))
+                            {
+                                @params = preProcessor.Process(lspDescriptor, @params);
+                            }
+
                             await ReflectionRequestHandlers.HandleNotification(descriptor, @params);
                         }
                     }
@@ -138,6 +147,7 @@ public async Task<ErrorResponse> RouteRequest(IHandlerDescriptor descriptor, Req
                             _logger.LogError(new EventId(-32602), cannotDeserializeRequestParams, "Failed to deserialise request parameters.");
                             return new InvalidParams(request.Id);
                         }
+
                         var lspDescriptor = descriptor as ILspHandlerDescriptor;
 
                         foreach (var preProcessor in _routeMatchers.ForHandlerPreProcessorMatcher()

src/Server/Matchers/ResolveCommandMatcher.cs

@@ -9,7 +9,7 @@
 
 namespace OmniSharp.Extensions.LanguageServer.Server.Matchers
 {
-    public class ResolveCommandMatcher : IHandlerMatcher, IHandlerPostProcessorMatcher, IHandlerPreProcessor, IHandlerPostProcessor
+    public class ResolveCommandMatcher : IHandlerMatcher, IHandlerPreProcessorMatcher, IHandlerPostProcessorMatcher, IHandlerPreProcessor, IHandlerPostProcessor
     {
         private readonly ILogger _logger;
         internal static string PrivateHandlerTypeName = "$$___handlerType___$$";
@@ -79,6 +79,17 @@ private static bool CanResolve<T>(ICanBeResolvedHandler<T> handler, T value)
             return handler.CanResolve(value);
         }
 
+        public IEnumerable<IHandlerPreProcessor> FindPreProcessor(ILspHandlerDescriptor descriptor, object parameters)
+        {
+            if (parameters is ICanBeResolved canBeResolved)
+            {
+                _logger.LogTrace("Using handler {Method}:{Handler}",
+                    descriptor.Method,
+                    descriptor.Handler.GetType().FullName);
+                yield return this;
+            }
+        }
+
         public IEnumerable<IHandlerPostProcessor> FindPostProcessor(ILspHandlerDescriptor descriptor, object parameters, object response)
         {
             if (descriptor.Method == DocumentNames.CodeLens || descriptor.Method == DocumentNames.Completion)