Improved RequestProcessingAsync legibility

With precomputed tasks

Hopefully #391, the good bits...

Author: benaadams

src/Microsoft.AspNet.Server.Kestrel/Http/Frame.cs

@@ -263,28 +263,15 @@ public async Task RequestProcessingAsync()
         {
             try
             {
-                var terminated = false;
-                while (!terminated && !_requestProcessingStopping)
+                while (!_requestProcessingStopping)
                 {
-                    while (!terminated && !_requestProcessingStopping && !TakeStartLine(SocketInput))
+                    if (!await ReadStartLineAsync() ||
+                        !await ReadHeadersAsync())
                     {
-                        terminated = SocketInput.RemoteIntakeFin;
-                        if (!terminated)
-                        {
-                            await SocketInput;
-                        }
-                    }
-
-                    while (!terminated && !_requestProcessingStopping && !TakeMessageHeaders(SocketInput, _requestHeaders))
-                    {
-                        terminated = SocketInput.RemoteIntakeFin;
-                        if (!terminated)
-                        {
-                            await SocketInput;
-                        }
+                        break;
                     }
 
-                    if (!terminated && !_requestProcessingStopping)
+                    if (!_requestProcessingStopping)
                     {
                         var messageBody = MessageBody.For(HttpVersion, _requestHeaders, this);
                         _keepAlive = messageBody.RequestKeepAlive;
@@ -337,7 +324,10 @@ public async Task RequestProcessingAsync()
                             _responseBody.StopAcceptingWrites();
                         }
 
-                        terminated = !_keepAlive;
+                        if (!_keepAlive)
+                        {
+                            break;
+                        }
                     }
 
                     Reset();
@@ -372,6 +362,62 @@ public async Task RequestProcessingAsync()
                 }
             }
         }
+        private Task<bool> ReadStartLineAsync()
+        {
+            if (!_requestProcessingStopping && !TakeStartLine(SocketInput))
+            {
+                if (SocketInput.RemoteIntakeFin)
+                {
+                    return TaskUtilities.CompletedFalseTask;
+                };
+                return ReadStartLineAwaitAsync();
+            }
+            return TaskUtilities.CompletedTrueTask;
+        }
+
+        private async Task<bool> ReadStartLineAwaitAsync()
+        {
+            await SocketInput;
+
+            while (!_requestProcessingStopping && !TakeStartLine(SocketInput))
+            {
+                if (SocketInput.RemoteIntakeFin)
+                {
+                    return false;
+                };
+
+                await SocketInput;
+            }
+            return true;
+        }
+
+        private Task<bool> ReadHeadersAsync()
+        {
+            if (!_requestProcessingStopping && !TakeMessageHeaders(SocketInput, _requestHeaders))
+            {
+                if (SocketInput.RemoteIntakeFin)
+                {
+                    return TaskUtilities.CompletedFalseTask;
+                };
+                return ReadHeadersAwaitAsync();
+            }
+            return TaskUtilities.CompletedTrueTask;
+        }
+
+        private async Task<bool> ReadHeadersAwaitAsync()
+        {
+            await SocketInput;
+
+            while (!_requestProcessingStopping && !TakeMessageHeaders(SocketInput, _requestHeaders))
+            {
+                if (SocketInput.RemoteIntakeFin)
+                {
+                    return false;
+                };
+                await SocketInput;
+            }
+            return true;
+        }
 
         public void OnStarting(Func<object, Task> callback, object state)
         {

src/Microsoft.AspNet.Server.Kestrel/Infrastructure/TaskUtilities.cs

@@ -12,5 +12,7 @@ public static class TaskUtilities
 #else
         public static Task CompletedTask = Task.FromResult<object>(null);
 #endif
+        public static Task<bool> CompletedTrueTask = Task.FromResult(true);
+        public static Task<bool> CompletedFalseTask = Task.FromResult(false);
     }
 }