A few HttpParser changes (#1624)

- Renamed KestrelHttpParser to HttpParser
- Removed the generic virtual dispatch as it turns out to be an
order of magnitude slower than regular virtual dispatch. This change
means we also lose the inlining of Frame.OnStartLine and Frame.OnHeader.

src/Microsoft.AspNetCore.Server.Kestrel.Core/Internal/Http/HttpParser.cs

@@ -10,9 +10,9 @@ using Microsoft.Extensions.Logging;
 
 namespace Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http
 {
-    public class KestrelHttpParser : IHttpParser
+    public class HttpParser : IHttpParser
     {
-        public KestrelHttpParser(IKestrelTrace log)
+        public HttpParser(IKestrelTrace log)
         {
             Log = log;
         }
@@ -28,7 +28,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http
         private const byte ByteQuestionMark = (byte)'?';
         private const byte BytePercentage = (byte)'%';
 
-        public unsafe bool ParseRequestLine<T>(T handler, ReadableBuffer buffer, out ReadCursor consumed, out ReadCursor examined) where T : IHttpRequestLineHandler
+        public unsafe bool ParseRequestLine(IHttpRequestLineHandler handler, ReadableBuffer buffer, out ReadCursor consumed, out ReadCursor examined)
         {
             consumed = buffer.Start;
             examined = buffer.End;
@@ -67,7 +67,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http
             return true;
         }
 
-        private unsafe void ParseRequestLine<T>(T handler, byte* data, int length) where T : IHttpRequestLineHandler
+        private unsafe void ParseRequestLine(IHttpRequestLineHandler handler, byte* data, int length)
         {
             int offset;
             Span<byte> customMethod = default(Span<byte>);
@@ -184,7 +184,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http
             handler.OnStartLine(method, httpVersion, targetBuffer, pathBuffer, query, customMethod, pathEncoded);
         }
 
-        public unsafe bool ParseHeaders<T>(T handler, ReadableBuffer buffer, out ReadCursor consumed, out ReadCursor examined, out int consumedBytes) where T : IHttpHeadersHandler
+        public unsafe bool ParseHeaders(IHttpHeadersHandler handler, ReadableBuffer buffer, out ReadCursor consumed, out ReadCursor examined, out int consumedBytes)
         {
             consumed = buffer.Start;
             examined = buffer.End;
@@ -347,7 +347,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http
         }
 
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        private unsafe void TakeSingleHeader<T>(byte* headerLine, int length, T handler) where T : IHttpHeadersHandler
+        private unsafe void TakeSingleHeader(byte* headerLine, int length, IHttpHeadersHandler handler)
         {
             // Skip CR, LF from end position
             var valueEnd = length - 3;

src/Microsoft.AspNetCore.Server.Kestrel.Core/Internal/Http/IHttpParser.cs

@@ -7,9 +7,9 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http
 {
     public interface IHttpParser
     {
-        bool ParseRequestLine<T>(T handler, ReadableBuffer buffer, out ReadCursor consumed, out ReadCursor examined) where T : IHttpRequestLineHandler;
+        bool ParseRequestLine(IHttpRequestLineHandler handler, ReadableBuffer buffer, out ReadCursor consumed, out ReadCursor examined);
 
-        bool ParseHeaders<T>(T handler, ReadableBuffer buffer, out ReadCursor consumed, out ReadCursor examined, out int consumedBytes) where T : IHttpHeadersHandler;
+        bool ParseHeaders(IHttpHeadersHandler handler, ReadableBuffer buffer, out ReadCursor consumed, out ReadCursor examined, out int consumedBytes);
 
         void Reset();
     }

src/Microsoft.AspNetCore.Server.Kestrel.Core/KestrelServer.cs

@@ -101,7 +101,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core
                 var serviceContext = new ServiceContext
                 {
                     Log = trace,
-                    HttpParserFactory = frame => new KestrelHttpParser(frame.ServiceContext.Log),
+                    HttpParserFactory = frame => new HttpParser(frame.ServiceContext.Log),
                     ThreadPool = threadPool,
                     DateHeaderValueManager = _dateHeaderValueManager,
                     ServerOptions = Options

test/Microsoft.AspNetCore.Server.Kestrel.Core.Tests/FrameResponseHeadersTests.cs

@@ -259,7 +259,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
 
         private class NoopHttpParser : IHttpParser
         {
-            public bool ParseHeaders<T>(T handler, ReadableBuffer buffer, out ReadCursor consumed, out ReadCursor examined, out int consumedBytes) where T : IHttpHeadersHandler
+            public bool ParseHeaders(IHttpHeadersHandler handler, ReadableBuffer buffer, out ReadCursor consumed, out ReadCursor examined, out int consumedBytes)
             {
                 consumed = buffer.Start;
                 examined = buffer.End;
@@ -267,7 +267,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
                 return false;
             }
 
-            public bool ParseRequestLine<T>(T handler, ReadableBuffer buffer, out ReadCursor consumed, out ReadCursor examined) where T : IHttpRequestLineHandler
+            public bool ParseRequestLine(IHttpRequestLineHandler handler, ReadableBuffer buffer, out ReadCursor consumed, out ReadCursor examined)
             {
                 consumed = buffer.Start;
                 examined = buffer.End;

test/Microsoft.AspNetCore.Server.Kestrel.Core.Tests/HttpParserTests.cs

@@ -418,7 +418,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             Assert.Equal(buffer.End, examined);
         }
 
-        private IHttpParser CreateParser(IKestrelTrace log) => new KestrelHttpParser(log);
+        private IHttpParser CreateParser(IKestrelTrace log) => new HttpParser(log);
 
         public static IEnumerable<string[]> RequestLineValidData => HttpParsingData.RequestLineValidData;
 

test/Microsoft.AspNetCore.Server.Kestrel.Performance/FrameParsingOverheadBenchmark.cs

@@ -114,7 +114,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Performance
 
             public static readonly NullParser Instance = new NullParser();
 
-            public bool ParseHeaders<T>(T handler, ReadableBuffer buffer, out ReadCursor consumed, out ReadCursor examined, out int consumedBytes) where T : IHttpHeadersHandler
+            public bool ParseHeaders(IHttpHeadersHandler handler, ReadableBuffer buffer, out ReadCursor consumed, out ReadCursor examined, out int consumedBytes)
             {
                 handler.OnHeader(new Span<byte>(_hostHeaderName), new Span<byte>(_hostHeaderValue));
                 handler.OnHeader(new Span<byte>(_acceptHeaderName), new Span<byte>(_acceptHeaderValue));
@@ -127,7 +127,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Performance
                 return true;
             }
 
-            public bool ParseRequestLine<T>(T handler, ReadableBuffer buffer, out ReadCursor consumed, out ReadCursor examined) where T : IHttpRequestLineHandler
+            public bool ParseRequestLine(IHttpRequestLineHandler handler, ReadableBuffer buffer, out ReadCursor consumed, out ReadCursor examined)
             {
                 handler.OnStartLine(HttpMethod.Get,
                     HttpVersion.Http11,

test/Microsoft.AspNetCore.Server.Kestrel.Performance/FrameWritingBenchmark.cs

@@ -94,7 +94,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Performance
                 DateHeaderValueManager = new DateHeaderValueManager(),
                 ServerOptions = new KestrelServerOptions(),
                 Log = new MockTrace(),
-                HttpParserFactory = f => new KestrelHttpParser(log: null)
+                HttpParserFactory = f => new HttpParser(log: null)
             };
             var frameContext = new FrameContext
             {

test/Microsoft.AspNetCore.Server.Kestrel.Performance/KestrelHttpParserBenchmark.cs

@@ -12,7 +12,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Performance
 
     public class KestrelHttpParserBenchmark : IHttpRequestLineHandler, IHttpHeadersHandler
     {
-        private readonly KestrelHttpParser _parser = new KestrelHttpParser(log: null);
+        private readonly HttpParser _parser = new HttpParser(log: null);
 
         private ReadableBuffer _buffer;
 

test/Microsoft.AspNetCore.Server.Kestrel.Performance/RequestParsingBenchmark.cs

@@ -23,7 +23,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Performance
         {
             var serviceContext = new ServiceContext
             {
-                HttpParserFactory = f => new KestrelHttpParser(f.ServiceContext.Log),
+                HttpParserFactory = f => new HttpParser(f.ServiceContext.Log),
                 ServerOptions = new KestrelServerOptions()
             };
             var frameContext = new FrameContext

test/Microsoft.AspNetCore.Server.Kestrel.Performance/ResponseHeaderCollectionBenchmark.cs

@@ -170,7 +170,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Performance
         {
             var serviceContext = new ServiceContext
             {
-                HttpParserFactory = f => new KestrelHttpParser(f.ServiceContext.Log),
+                HttpParserFactory = f => new HttpParser(f.ServiceContext.Log),
                 ServerOptions = new KestrelServerOptions()
             };
             var frameContext = new FrameContext

test/Microsoft.AspNetCore.Server.Kestrel.Performance/ResponseHeadersWritingBenchmark.cs

@@ -120,7 +120,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Performance
                 DateHeaderValueManager = new DateHeaderValueManager(),
                 ServerOptions = new KestrelServerOptions(),
                 Log = new MockTrace(),
-                HttpParserFactory = f => new KestrelHttpParser(log: null)
+                HttpParserFactory = f => new HttpParser(log: null)
             };
 
             var frameContext = new FrameContext

test/shared/TestServiceContext.cs

@@ -18,7 +18,7 @@ namespace Microsoft.AspNetCore.Testing
             ThreadPool = new LoggingThreadPool(Log);
             DateHeaderValueManager = new DateHeaderValueManager(systemClock: new MockSystemClock());
             DateHeaderValue = DateHeaderValueManager.GetDateHeaderValues().String;
-            HttpParserFactory = frame => new KestrelHttpParser(frame.ServiceContext.Log);
+            HttpParserFactory = frame => new HttpParser(frame.ServiceContext.Log);
             ServerOptions = new KestrelServerOptions
             {
                 AddServerHeader = false