Merge branch 'benaadams/valuetask' into dev

src/Microsoft.AspNet.Server.Kestrel/Filter/LibuvStream.cs

@@ -11,9 +11,13 @@ namespace Microsoft.AspNet.Server.Kestrel.Filter
 {
     public class LibuvStream : Stream
     {
+        private readonly static Task<int> _initialCachedTask = Task.FromResult(0);
+
         private readonly SocketInput _input;
         private readonly ISocketOutput _output;
 
+        private Task<int> _cachedTask = _initialCachedTask;
+
         public LibuvStream(SocketInput input, ISocketOutput output)
         {
             _input = input;
@@ -58,12 +62,30 @@ namespace Microsoft.AspNet.Server.Kestrel.Filter
 
         public override int Read(byte[] buffer, int offset, int count)
         {
-            return ReadAsync(new ArraySegment<byte>(buffer, offset, count)).GetAwaiter().GetResult();
+            // ValueTask uses .GetAwaiter().GetResult() if necessary
+            // https://github.com/dotnet/corefx/blob/f9da3b4af08214764a51b2331f3595ffaf162abe/src/System.Threading.Tasks.Extensions/src/System/Threading/Tasks/ValueTask.cs#L156
+            return ReadAsync(new ArraySegment<byte>(buffer, offset, count)).Result;
         }
 
         public override Task<int> ReadAsync(byte[] buffer, int offset, int count, CancellationToken cancellationToken)
         {
-            return ReadAsync(new ArraySegment<byte>(buffer, offset, count));
+            var task = ReadAsync(new ArraySegment<byte>(buffer, offset, count));
+
+            if (task.IsCompletedSuccessfully)
+            {
+                if (_cachedTask.Result != task.Result)
+                {
+                    // Needs .AsTask to match Stream's Async method return types
+                    _cachedTask = task.AsTask();
+                }
+            }
+            else
+            {
+                // Needs .AsTask to match Stream's Async method return types
+                _cachedTask = task.AsTask();
+            }
+
+            return _cachedTask;
         }
 
         public override void Write(byte[] buffer, int offset, int count)
@@ -99,7 +121,7 @@ namespace Microsoft.AspNet.Server.Kestrel.Filter
             // No-op since writes are immediate.
         }
 
-        private Task<int> ReadAsync(ArraySegment<byte> buffer)
+        private ValueTask<int> ReadAsync(ArraySegment<byte> buffer)
         {
             return _input.ReadAsync(buffer.Array, buffer.Offset, buffer.Count);
         }

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

@@ -53,7 +53,8 @@ namespace Microsoft.AspNet.Server.Kestrel.Http
         {
             ValidateState();
 
-            return ReadAsync(buffer, offset, count).GetAwaiter().GetResult();
+            // ValueTask uses .GetAwaiter().GetResult() if necessary
+            return ReadAsync(buffer, offset, count).Result;
         }
 
 #if NET451
@@ -80,7 +81,7 @@ namespace Microsoft.AspNet.Server.Kestrel.Http
 
             var tcs = new TaskCompletionSource<int>(state);
             var task = _body.ReadAsync(new ArraySegment<byte>(buffer, offset, count), cancellationToken);
-            task.ContinueWith((task2, state2) =>
+            task.AsTask().ContinueWith((task2, state2) =>
             {
                 var tcs2 = (TaskCompletionSource<int>)state2;
                 if (task2.IsCanceled)
@@ -104,7 +105,8 @@ namespace Microsoft.AspNet.Server.Kestrel.Http
         {
             ValidateState();
 
-            return _body.ReadAsync(new ArraySegment<byte>(buffer, offset, count), cancellationToken);
+            // Needs .AsTask to match Stream's Async method return types
+            return _body.ReadAsync(new ArraySegment<byte>(buffer, offset, count), cancellationToken).AsTask();
         }
 
         public override void Write(byte[] buffer, int offset, int count)

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

@@ -22,11 +22,10 @@ namespace Microsoft.AspNet.Server.Kestrel.Http
 
         public bool RequestKeepAlive { get; protected set; }
 
-        public Task<int> ReadAsync(ArraySegment<byte> buffer, CancellationToken cancellationToken = default(CancellationToken))
+        public ValueTask<int> ReadAsync(ArraySegment<byte> buffer, CancellationToken cancellationToken = default(CancellationToken))
         {
-            Task<int> result = null;
             var send100Continue = 0;
-            result = ReadAsyncImplementation(buffer, cancellationToken);
+            var result = ReadAsyncImplementation(buffer, cancellationToken);
             if (!result.IsCompleted)
             {
                 send100Continue = Interlocked.Exchange(ref _send100Continue, 0);
@@ -40,7 +39,7 @@ namespace Microsoft.AspNet.Server.Kestrel.Http
 
         public async Task Consume(CancellationToken cancellationToken = default(CancellationToken))
         {
-            Task<int> result;
+            ValueTask<int> result;
             var send100checked = false;
             do
             {
@@ -56,7 +55,8 @@ namespace Microsoft.AspNet.Server.Kestrel.Http
                         send100checked = true;
                     }
                 }
-                else if (result.GetAwaiter().GetResult() == 0) 
+                // ValueTask uses .GetAwaiter().GetResult() if necessary
+                else if (result.Result == 0) 
                 {
                     // Completed Task, end of stream
                     return;
@@ -69,7 +69,7 @@ namespace Microsoft.AspNet.Server.Kestrel.Http
             } while (await result != 0);
         }
 
-        public abstract Task<int> ReadAsyncImplementation(ArraySegment<byte> buffer, CancellationToken cancellationToken);
+        public abstract ValueTask<int> ReadAsyncImplementation(ArraySegment<byte> buffer, CancellationToken cancellationToken);
 
         public static MessageBody For(
             string httpVersion,
@@ -137,7 +137,7 @@ namespace Microsoft.AspNet.Server.Kestrel.Http
             {
             }
 
-            public override Task<int> ReadAsyncImplementation(ArraySegment<byte> buffer, CancellationToken cancellationToken)
+            public override ValueTask<int> ReadAsyncImplementation(ArraySegment<byte> buffer, CancellationToken cancellationToken)
             {
                 return _context.SocketInput.ReadAsync(buffer.Array, buffer.Offset, buffer.Array == null ? 8192 : buffer.Count);
             }
@@ -156,7 +156,7 @@ namespace Microsoft.AspNet.Server.Kestrel.Http
                 _inputLength = _contentLength;
             }
 
-            public override async Task<int> ReadAsyncImplementation(ArraySegment<byte> buffer, CancellationToken cancellationToken)
+            public override ValueTask<int> ReadAsyncImplementation(ArraySegment<byte> buffer, CancellationToken cancellationToken)
             {
                 var input = _context.SocketInput;
 
@@ -166,9 +166,29 @@ namespace Microsoft.AspNet.Server.Kestrel.Http
                     return 0;
                 }
 
-                var actual = await _context.SocketInput.ReadAsync(buffer.Array, buffer.Offset, limit);
+                var task = _context.SocketInput.ReadAsync(buffer.Array, buffer.Offset, limit);
-                _inputLength -= actual;
 
+                if (task.IsCompleted)
+                {
+                    // .GetAwaiter().GetResult() done by ValueTask if needed
+                    var actual = task.Result;
+                    _inputLength -= actual;
+                    if (actual == 0)
+                    {
+                        throw new InvalidDataException("Unexpected end of request content");
+                    }
+                    return actual;
+                }
+                else
+                {
+                    return ReadAsyncAwaited(task.AsTask());
+                }
+            }
+
+            private async Task<int> ReadAsyncAwaited(Task<int> task)
+            {
+                var actual = await task;
+                _inputLength -= actual;
                 if (actual == 0)
                 {
                     throw new InvalidDataException("Unexpected end of request content");
@@ -178,7 +198,6 @@ namespace Microsoft.AspNet.Server.Kestrel.Http
             }
         }
 
-
         /// <summary>
         ///   http://tools.ietf.org/html/rfc2616#section-3.6.1
         /// </summary>
@@ -193,8 +212,12 @@ namespace Microsoft.AspNet.Server.Kestrel.Http
             {
                 RequestKeepAlive = keepAlive;
             }
+            public override ValueTask<int> ReadAsyncImplementation(ArraySegment<byte> buffer, CancellationToken cancellationToken)
+            {
+                return ReadAsyncAwaited(buffer, cancellationToken);
+            }
 
-            public override async Task<int> ReadAsyncImplementation(ArraySegment<byte> buffer, CancellationToken cancellationToken)
+            private async Task<int> ReadAsyncAwaited(ArraySegment<byte> buffer, CancellationToken cancellationToken)
             {
                 var input = _context.SocketInput;
 

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

@@ -8,7 +8,33 @@ namespace Microsoft.AspNet.Server.Kestrel.Http
 {
     public static class SocketInputExtensions
     {
-        public static async Task<int> ReadAsync(this SocketInput input, byte[] buffer, int offset, int count)
+        public static ValueTask<int> ReadAsync(this SocketInput input, byte[] buffer, int offset, int count)
+        {
+            while (true)
+            {
+                if (!input.IsCompleted)
+                {
+                    return input.ReadAsyncAwaited(buffer, offset, count);
+                }
+
+                var begin = input.ConsumingStart();
+
+                int actual;
+                var end = begin.CopyTo(buffer, offset, count, out actual);
+                input.ConsumingComplete(end, end);
+
+                if (actual != 0)
+                {
+                    return actual;
+                }
+                if (input.RemoteIntakeFin)
+                {
+                    return 0;
+                }
+            }
+        }
+
+        private static async Task<int> ReadAsyncAwaited(this SocketInput input, byte[] buffer, int offset, int count)
         {
             while (true)
             {

src/Microsoft.AspNet.Server.Kestrel/project.json

@@ -20,7 +20,8 @@
     "Microsoft.AspNet.Internal.libuv-Windows": {
       "version": "1.0.0-*",
       "type": "build"
-    }
+    },
+    "System.Threading.Tasks.Extensions": "4.0.0-*"
   },
   "frameworks": {
     "dnx451": { },