Replace custom DateTimeFormatter with ToString("r") or TryFormat (#5695)

src/Http/Headers/src/DateTimeFormatter.cs

@@ -1,100 +0,0 @@
-// Copyright (c) .NET Foundation. All rights reserved.
-// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
-
-using System;
-using System.Globalization;
-using System.Runtime.CompilerServices;
-using Microsoft.Extensions.Primitives;
-
-namespace Microsoft.Net.Http.Headers
-{
-    internal static class DateTimeFormatter
-    {
-        private static readonly DateTimeFormatInfo FormatInfo = CultureInfo.InvariantCulture.DateTimeFormat;
-
-        private static readonly string[] MonthNames = FormatInfo.AbbreviatedMonthNames;
-        private static readonly string[] DayNames = FormatInfo.AbbreviatedDayNames;
-
-        private static readonly int Rfc1123DateLength = "ddd, dd MMM yyyy HH:mm:ss GMT".Length;
-        private static readonly int QuotedRfc1123DateLength = Rfc1123DateLength + 2;
-
-        // ASCII numbers are in the range 48 - 57.
-        private const int AsciiNumberOffset = 0x30;
-
-        private const string Gmt = "GMT";
-        private const char Comma = ',';
-        private const char Space = ' ';
-        private const char Colon = ':';
-        private const char Quote = '"';
-
-        public static string ToRfc1123String(this DateTimeOffset dateTime)
-        {
-            return ToRfc1123String(dateTime, false);
-        }
-
-        public static string ToRfc1123String(this DateTimeOffset dateTime, bool quoted)
-        {
-            var universal = dateTime.UtcDateTime;
-
-            var length = quoted ? QuotedRfc1123DateLength : Rfc1123DateLength;
-            var target = new InplaceStringBuilder(length);
-
-            if (quoted)
-            {
-                target.Append(Quote);
-            }
-
-            target.Append(DayNames[(int)universal.DayOfWeek]);
-            target.Append(Comma);
-            target.Append(Space);
-            AppendNumber(ref target, universal.Day);
-            target.Append(Space);
-            target.Append(MonthNames[universal.Month - 1]);
-            target.Append(Space);
-            AppendYear(ref target, universal.Year);
-            target.Append(Space);
-            AppendTimeOfDay(ref target, universal.TimeOfDay);
-            target.Append(Space);
-            target.Append(Gmt);
-
-            if (quoted)
-            {
-                target.Append(Quote);
-            }
-
-            return target.ToString();
-        }
-
-        [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        private static void AppendYear(ref InplaceStringBuilder target, int year)
-        {
-            target.Append(GetAsciiChar(year / 1000));
-            target.Append(GetAsciiChar(year % 1000 / 100));
-            target.Append(GetAsciiChar(year % 100 / 10));
-            target.Append(GetAsciiChar(year % 10));
-        }
-
-        [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        private static void AppendTimeOfDay(ref InplaceStringBuilder target, TimeSpan timeOfDay)
-        {
-            AppendNumber(ref target, timeOfDay.Hours);
-            target.Append(Colon);
-            AppendNumber(ref target, timeOfDay.Minutes);
-            target.Append(Colon);
-            AppendNumber(ref target, timeOfDay.Seconds);
-        }
-
-        [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        private static void AppendNumber(ref InplaceStringBuilder target, int number)
-        {
-            target.Append(GetAsciiChar(number / 10));
-            target.Append(GetAsciiChar(number % 10));
-        }
-
-        [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        private static char GetAsciiChar(int value)
-        {
-            return (char)(AsciiNumberOffset + value);
-        }
-    }
-}

src/Http/Headers/src/HeaderUtilities.cs

@@ -589,7 +589,16 @@ namespace Microsoft.Net.Http.Headers
 
         public static string FormatDate(DateTimeOffset dateTime, bool quoted)
         {
-            return dateTime.ToRfc1123String(quoted);
+            if (quoted)
+            {
+                return string.Create(31, dateTime, (span, dt) =>
+                {
+                    span[0] = span[30] = '"';
+                    dt.TryFormat(span.Slice(1), out _, "r");
+                });
+            }
+
+            return dateTime.ToString("r");
         }
 
         public static StringSegment RemoveQuotes(StringSegment input)