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// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
using System.Buffers.Binary;
using System.Diagnostics;
using System.Globalization;
using System.Text;
using Microsoft.AspNetCore.Http;
namespace CodeGenerator.HttpUtilities;
public class HttpUtilities
{
public static string GeneratedFile()
{
var httpMethods = new[]
{
new Tuple<string, String>("CONNECT ", "Connect"),
new Tuple<string, String>("DELETE ", "Delete"),
new Tuple<string, String>("HEAD ", "Head"),
new Tuple<string, String>("PATCH ", "Patch"),
new Tuple<string, String>("POST ", "Post"),
new Tuple<string, String>("PUT ", "Put"),
new Tuple<string, String>("OPTIONS ", "Options"),
new Tuple<string, String>("TRACE ", "Trace"),
new Tuple<string, String>("GET ", "Get")
};
return GenerateFile(httpMethods);
}
private static string GenerateFile(Tuple<string, String>[] httpMethods)
{
var maskLength = (byte)Math.Ceiling(Math.Log(httpMethods.Length, 2));
var methodsInfo = httpMethods.Select(GetMethodStringAndUlongAndMaskLength).ToList();
var methodsInfoWithoutGet = methodsInfo.Where(m => m.HttpMethod != "Get").ToList();
var methodsAsciiStringAsLong = methodsInfo.Select(m => m.AsciiStringAsLong).ToArray();
var mask = HttpUtilitiesGeneratorHelpers.SearchKeyByLookThroughMaskCombinations(methodsAsciiStringAsLong, 0, sizeof(ulong) * 8, maskLength);
if (mask.HasValue == false)
{
throw new InvalidOperationException(string.Format(CultureInfo.InvariantCulture, "Generated {0} not found.", nameof(mask)));
}
var functionGetKnownMethodIndex = GetFunctionBodyGetKnownMethodIndex(mask.Value);
var methodsSection = GetMethodsSection(methodsInfoWithoutGet);
var masksSection = GetMasksSection(methodsInfoWithoutGet);
var setKnownMethodSection = GetSetKnownMethodSection(methodsInfoWithoutGet);
var methodNamesSection = GetMethodNamesSection(methodsInfo);
int knownMethodsArrayLength = (int)(Math.Pow(2, maskLength) + 1);
int methodNamesArrayLength = httpMethods.Length;
return string.Format(CultureInfo.InvariantCulture, @"// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
using System;
using System.Runtime.CompilerServices;
using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http;
#nullable enable
namespace Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Infrastructure
{{
internal static partial class HttpUtilities
{{
// readonly primitive statics can be Jit'd to consts https://github.com/dotnet/coreclr/issues/1079
{0}
{1}
private static readonly Tuple<ulong, ulong, HttpMethod, int>[] _knownMethods =
new Tuple<ulong, ulong, HttpMethod, int>[{2}];
private static readonly string[] _methodNames = new string[{3}];
static HttpUtilities()
{{
{4}
FillKnownMethodsGaps();
{5}
}}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
private static int GetKnownMethodIndex(ulong value)
{{
{6}
}}
}}
}}", methodsSection, masksSection, knownMethodsArrayLength, methodNamesArrayLength, setKnownMethodSection, methodNamesSection, functionGetKnownMethodIndex);
}
private static string GetMethodsSection(List<MethodInfo> methodsInfo)
{
var result = new StringBuilder();
for (var index = 0; index < methodsInfo.Count; index++)
{
var methodInfo = methodsInfo[index];
var httpMethodFieldName = GetHttpMethodFieldName(methodInfo);
result.AppendFormat(CultureInfo.InvariantCulture, " private static readonly ulong {0} = GetAsciiStringAsLong(\"{1}\");", httpMethodFieldName, methodInfo.MethodAsciiString.Replace("\0", "\\0"));
if (index < methodsInfo.Count - 1)
{
result.AppendLine();
}
}
return result.ToString();
}
private static string GetMasksSection(List<MethodInfo> methodsInfo)
{
var distinctLengths = methodsInfo.Select(m => m.MaskLength).Distinct().ToList();
distinctLengths.Sort((t1, t2) => -t1.CompareTo(t2));
var result = new StringBuilder();
for (var index = 0; index < distinctLengths.Count; index++)
{
var maskBytesLength = distinctLengths[index];
var maskArray = GetMaskArray(maskBytesLength);
var hexMaskString = HttpUtilitiesGeneratorHelpers.GeHexString(maskArray, "0x", ", ");
var maskFieldName = GetMaskFieldName(maskBytesLength);
result.AppendFormat(CultureInfo.InvariantCulture, """ private static readonly ulong {0} = GetMaskAsLong([{1}]);""", maskFieldName, hexMaskString);
result.AppendLine();
if (index < distinctLengths.Count - 1)
{
result.AppendLine();
}
}
return result.ToString();
}
private static string GetSetKnownMethodSection(List<MethodInfo> methodsInfo)
{
methodsInfo = methodsInfo.ToList();
methodsInfo.Sort((t1, t2) => t1.MaskLength.CompareTo(t2.MaskLength));
var result = new StringBuilder();
for (var index = 0; index < methodsInfo.Count; index++)
{
var methodInfo = methodsInfo[index];
var maskFieldName = GetMaskFieldName(methodInfo.MaskLength);
var httpMethodFieldName = GetHttpMethodFieldName(methodInfo);
result.AppendFormat(CultureInfo.InvariantCulture, " SetKnownMethod({0}, {1}, HttpMethod.{3}, {4});", maskFieldName, httpMethodFieldName, typeof(String).Name, methodInfo.HttpMethod, methodInfo.MaskLength - 1);
if (index < methodsInfo.Count - 1)
{
result.AppendLine();
}
}
return result.ToString();
}
private static string GetMethodNamesSection(List<MethodInfo> methodsInfo)
{
methodsInfo = methodsInfo.ToList();
methodsInfo.Sort((t1, t2) => string.Compare(t1.HttpMethod, t2.HttpMethod, StringComparison.Ordinal));
var result = new StringBuilder();
for (var index = 0; index < methodsInfo.Count; index++)
{
var methodInfo = methodsInfo[index];
result.AppendFormat(CultureInfo.InvariantCulture, " _methodNames[(byte)HttpMethod.{1}] = {2}.{3};", typeof(String).Name, methodInfo.HttpMethod, typeof(HttpMethods).Name, methodInfo.HttpMethod);
if (index < methodsInfo.Count - 1)
{
result.AppendLine();
}
}
return result.ToString();
}
private static string GetFunctionBodyGetKnownMethodIndex(ulong mask)
{
var shifts = HttpUtilitiesGeneratorHelpers.GetShifts(mask);
var maskHexString = HttpUtilitiesGeneratorHelpers.MaskToHexString(mask);
string bodyString;
if (shifts.Length > 0)
{
var bitsCount = HttpUtilitiesGeneratorHelpers.CountBits(mask);
var tmpReturn = string.Empty;
foreach (var item in shifts)
{
if (tmpReturn.Length > 0)
{
tmpReturn += " | ";
}
tmpReturn += string.Format(CultureInfo.InvariantCulture, "(tmp >> {1})", HttpUtilitiesGeneratorHelpers.MaskToHexString(item.Mask), item.Shift);
}
var mask2 = (ulong)(Math.Pow(2, bitsCount) - 1);
string returnString = string.Format(CultureInfo.InvariantCulture, "return ({0}) & {1};", tmpReturn, HttpUtilitiesGeneratorHelpers.MaskToHexString(mask2));
bodyString = string.Format(CultureInfo.InvariantCulture, " const int magicNumer = {0};\r\n var tmp = (int)value & magicNumer;\r\n {1}", HttpUtilitiesGeneratorHelpers.MaskToHexString(mask), returnString);
}
else
{
bodyString = string.Format(CultureInfo.InvariantCulture, "return (int)(value & {0});", maskHexString);
}
return bodyString;
}
private static string GetHttpMethodFieldName(MethodInfo methodsInfo)
{
return string.Format(CultureInfo.InvariantCulture, "_http{0}MethodLong", methodsInfo.HttpMethod.ToString());
}
private static string GetMaskFieldName(int nBytes)
{
return string.Format(CultureInfo.InvariantCulture, "_mask{0}Chars", nBytes);
}
private static string GetMethodString(string method)
{
ArgumentNullException.ThrowIfNull(method);
const int length = sizeof(ulong);
if (method.Length > length)
{
throw new ArgumentException(string.Format(CultureInfo.CurrentCulture, "MethodAsciiString {0} length is greather than {1}", method, length));
}
string result = method;
if (result.Length == length)
{
return result;
}
if (result.Length < length)
{
var count = length - result.Length;
for (int i = 0; i < count; i++)
{
result += "\0";
}
}
return result;
}
private sealed class MethodInfo
{
public string MethodAsciiString;
public ulong AsciiStringAsLong;
public string HttpMethod;
public int MaskLength;
}
private static MethodInfo GetMethodStringAndUlongAndMaskLength(Tuple<string, string> method)
{
var methodString = GetMethodString(method.Item1);
var asciiAsLong = GetAsciiStringAsLong(methodString);
return new MethodInfo
{
MethodAsciiString = methodString,
AsciiStringAsLong = asciiAsLong,
HttpMethod = method.Item2.ToString(),
MaskLength = method.Item1.Length
};
}
private static byte[] GetMaskArray(int n, int length = sizeof(ulong))
{
var maskArray = new byte[length];
for (int i = 0; i < n; i++)
{
maskArray[i] = 0xff;
}
return maskArray;
}
private static ulong GetAsciiStringAsLong(string str)
{
Debug.Assert(str.Length == sizeof(ulong), string.Format(CultureInfo.InvariantCulture, "String must be exactly {0} (ASCII) characters long.", sizeof(ulong)));
var bytes = Encoding.ASCII.GetBytes(str);
return BinaryPrimitives.ReadUInt64LittleEndian(bytes);
}
}
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