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Speed up PathStringHelper (#9709)

This commit is contained in:
Ben Adams 2019-04-30 16:13:03 +01:00 committed by David Fowler
parent 5c7c621895
commit caf4374f83
2 changed files with 80 additions and 44 deletions
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74
src/Http/Http.Abstractions/src/Internal/PathStringHelper.cs
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@ -1,47 +1,67 @@
// 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.Diagnostics;
using System.Runtime.CompilerServices;
namespace Microsoft.AspNetCore.Http.Internal
{
internal class PathStringHelper
internal static class PathStringHelper
{
private static bool[] ValidPathChars = {
false, false, false, false, false, false, false, false, // 0x00 - 0x07
false, false, false, false, false, false, false, false, // 0x08 - 0x0F
false, false, false, false, false, false, false, false, // 0x10 - 0x17
false, false, false, false, false, false, false, false, // 0x18 - 0x1F
false, true, false, false, true, false, true, true, // 0x20 - 0x27
true, true, true, true, true, true, true, true, // 0x28 - 0x2F
true, true, true, true, true, true, true, true, // 0x30 - 0x37
true, true, true, true, false, true, false, false, // 0x38 - 0x3F
true, true, true, true, true, true, true, true, // 0x40 - 0x47
true, true, true, true, true, true, true, true, // 0x48 - 0x4F
true, true, true, true, true, true, true, true, // 0x50 - 0x57
true, true, true, false, false, false, false, true, // 0x58 - 0x5F
false, true, true, true, true, true, true, true, // 0x60 - 0x67
true, true, true, true, true, true, true, true, // 0x68 - 0x6F
true, true, true, true, true, true, true, true, // 0x70 - 0x77
true, true, true, false, false, false, true, false, // 0x78 - 0x7F
// uint[] bits uses 1 cache line (Array info + 16 bytes)
// bool[] would use 3 cache lines (Array info + 128 bytes)
// So we use 128 bits rather than 128 bytes/bools
private static readonly uint[] ValidPathChars = {
0b_0000_0000__0000_0000__0000_0000__0000_0000, // 0x00 - 0x1F
0b_0010_1111__1111_1111__1111_1111__1101_0010, // 0x20 - 0x3F
0b_1000_0111__1111_1111__1111_1111__1111_1111, // 0x40 - 0x5F
0b_0100_0111__1111_1111__1111_1111__1111_1110, // 0x60 - 0x7F
};
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public static bool IsValidPathChar(char c)
{
return c < ValidPathChars.Length && ValidPathChars[c];
// Use local array and uint .Length compare to elide the bounds check on array access
var validChars = ValidPathChars;
var i = (int)c;
// Array is in chunks of 32 bits, so get offset by dividing by 32
var offset = i >> 5; // i / 32;
// Significant bit position is the remainder of the above calc; i % 32 => i & 31
var significantBit = 1u << (i & 31);
// Check offset in bounds and check if significant bit set
return (uint)offset < (uint)validChars.Length &&
((validChars[offset] & significantBit) != 0);
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public static bool IsPercentEncodedChar(string str, int index)
{
return index < str.Length - 2
&& str[index] == '%'
&& IsHexadecimalChar(str[index + 1])
&& IsHexadecimalChar(str[index + 2]);
var len = (uint)str.Length;
if (str[index] == '%' && index < len - 2)
{
return AreFollowingTwoCharsHex(str, index);
}
return false;
}
public static bool IsHexadecimalChar(char c)
[MethodImpl(MethodImplOptions.NoInlining)]
private static bool AreFollowingTwoCharsHex(string str, int index)
{
return ('0' <= c && c <= '9')
|| ('A' <= c && c <= 'F')
|| ('a' <= c && c <= 'f');
Debug.Assert(index < str.Length - 2);
var c1 = str[index + 1];
var c2 = str[index + 2];
return IsHexadecimalChar(c1) && IsHexadecimalChar(c2);
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
private static bool IsHexadecimalChar(char c)
{
// Between 0 - 9 or uppercased between A - F
return (uint)(c - '0') <= 9 || (uint)((c & ~0x20) - 'A') <= ('F' - 'A');
}
}
}

50
src/Http/Http.Abstractions/src/PathString.cs
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@ -16,8 +16,6 @@ namespace Microsoft.AspNetCore.Http
[TypeConverter(typeof(PathStringConverter))]
public readonly struct PathString : IEquatable<PathString>
{
private static readonly char[] splitChar = { '/' };
/// <summary>
/// Represents the empty path. This field is read-only.
/// </summary>
@ -75,27 +73,46 @@ namespace Microsoft.AspNetCore.Http
return string.Empty;
}
var value = _value;
var i = 0;
for (; i < value.Length; i++)
{
if (!PathStringHelper.IsValidPathChar(value[i]) || PathStringHelper.IsPercentEncodedChar(value, i))
{
break;
}
}
if (i < value.Length)
{
return ToEscapedUriComponent(value, i);
}
return value;
}
private static string ToEscapedUriComponent(string value, int i)
{
StringBuilder buffer = null;
var start = 0;
var count = 0;
var count = i;
var requiresEscaping = false;
var i = 0;
while (i < _value.Length)
while (i < value.Length)
{
var isPercentEncodedChar = PathStringHelper.IsPercentEncodedChar(_value, i);
if (PathStringHelper.IsValidPathChar(_value[i]) || isPercentEncodedChar)
var isPercentEncodedChar = PathStringHelper.IsPercentEncodedChar(value, i);
if (PathStringHelper.IsValidPathChar(value[i]) || isPercentEncodedChar)
{
if (requiresEscaping)
{
// the current segment requires escape
if (buffer == null)
{
buffer = new StringBuilder(_value.Length * 3);
buffer = new StringBuilder(value.Length * 3);
}
buffer.Append(Uri.EscapeDataString(_value.Substring(start, count)));
buffer.Append(Uri.EscapeDataString(value.Substring(start, count)));
requiresEscaping = false;
start = i;
@ -120,10 +137,10 @@ namespace Microsoft.AspNetCore.Http
// the current segment doesn't require escape
if (buffer == null)
{
buffer = new StringBuilder(_value.Length * 3);
buffer = new StringBuilder(value.Length * 3);
}
buffer.Append(_value, start, count);
buffer.Append(value, start, count);
requiresEscaping = true;
start = i;
@ -135,9 +152,9 @@ namespace Microsoft.AspNetCore.Http
}
}
if (count == _value.Length && !requiresEscaping)
if (count == value.Length && !requiresEscaping)
{
return _value;
return value;
}
else
{
@ -145,16 +162,16 @@ namespace Microsoft.AspNetCore.Http
{
if (buffer == null)
{
buffer = new StringBuilder(_value.Length * 3);
buffer = new StringBuilder(value.Length * 3);
}
if (requiresEscaping)
{
buffer.Append(Uri.EscapeDataString(_value.Substring(start, count)));
buffer.Append(Uri.EscapeDataString(value.Substring(start, count)));
}
else
{
buffer.Append(_value, start, count);
buffer.Append(value, start, count);
}
}
@ -162,7 +179,6 @@ namespace Microsoft.AspNetCore.Http
}
}
/// <summary>
/// Returns an PathString given the path as it is escaped in the URI format. The string MUST NOT contain any
/// value that is not a path.