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Merged
SimonCropp merged 1 commit into from
Oct 12, 2026
Merged

Use the regex cache for static Regex.Count and Regex.EnumerateSplits #705

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4 changes: 2 additions & 2 deletions apiCount.include.md
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Expand Up @@ -20,8 +20,8 @@
| `netcoreapp3.1` | 880 |
| `net5.0` | 764 |
| `net6.0` | 660 |
| `net7.0` | 519 |
| `net8.0` | 400 |
| `net7.0` | 520 |
| `net8.0` | 401 |
| `net9.0` | 253 |
| `net10.0` | 186 |
| `net11.0` | 56 |
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4 changes: 2 additions & 2 deletions readme.md
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Expand Up @@ -35,8 +35,8 @@ The package targets `netstandard2.0` and is designed to support the following ru
| `netcoreapp3.1` | 880 |
| `net5.0` | 764 |
| `net6.0` | 660 |
| `net7.0` | 519 |
| `net8.0` | 400 |
| `net7.0` | 520 |
| `net8.0` | 401 |
| `net9.0` | 253 |
| `net10.0` | 186 |
| `net11.0` | 56 |
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48 changes: 40 additions & 8 deletions src/Polyfill/Regex/RegexCache.cs
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@@ -1,7 +1,7 @@
// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.

#if !NET7_0_OR_GREATER && FeatureMemory
#if !NET9_0_OR_GREATER
#nullable enable
namespace System.Text.RegularExpressions;

Expand All @@ -10,15 +10,16 @@ namespace System.Text.RegularExpressions;
using System.Collections.Generic;
using System.Diagnostics.CodeAnalysis;
using System.Diagnostics;
using System.Globalization;
using System.Threading;

// https://github.com/dotnet/runtime/blob/main/src/libraries/System.Text.RegularExpressions/src/System/Text/RegularExpressions/Regex.Cache.cs
/// <summary>Cache used to store Regex instances used by the static methods on Regex.</summary>
[ExcludeFromCodeCoverage]
[DebuggerNonUserCode]
#if PolyUseEmbeddedAttribute
[global::Microsoft.CodeAnalysis.EmbeddedAttribute]
#endif
// https://github.com/dotnet/runtime/blob/main/src/libraries/System.Text.RegularExpressions/src/System/Text/RegularExpressions/Regex.Cache.cs
/// <summary>Cache used to store Regex instances used by the static methods on Regex.</summary>
internal sealed class RegexCache
{
const int DefaultMaxCacheSize = 15;
Expand Down Expand Up @@ -67,14 +68,26 @@ public static int MaxCacheSize
}
}

public static Regex GetOrAdd(string pattern)
// Keys a regex constructed without an explicit timeout, which takes the default match timeout. Not a valid
// match timeout, so it never collides with an explicit one.
static readonly TimeSpan s_defaultTimeoutKey = TimeSpan.MinValue;

public static Regex GetOrAdd(string pattern) =>
GetOrAdd(pattern, RegexOptions.None);

public static Regex GetOrAdd(string pattern, RegexOptions options)
{
var key = new Key(pattern, RegexOptions.None, Regex.InfiniteMatchTimeout);
if (pattern is null)
{
throw new ArgumentNullException(nameof(pattern));
}

var key = new Key(pattern, GetCultureKey(options), options, s_defaultTimeoutKey);

var regex = Get(key);
if (regex is null)
{
regex = new Regex(pattern);
regex = new Regex(pattern, options);
Add(key, regex);
}

Expand All @@ -83,7 +96,12 @@ public static Regex GetOrAdd(string pattern)

public static Regex GetOrAdd(string pattern, RegexOptions options, TimeSpan matchTimeout)
{
Key key = new Key(pattern, options, matchTimeout);
if (pattern is null)
{
throw new ArgumentNullException(nameof(pattern));
}

Key key = new Key(pattern, GetCultureKey(options), options, matchTimeout);

Regex? regex = Get(key);
if (regex is null)
Expand All @@ -95,6 +113,17 @@ public static Regex GetOrAdd(string pattern, RegexOptions options, TimeSpan matc
return regex;
}

// A regex captures the casing rules of the culture it was constructed under, so the culture is part of the key.
static string GetCultureKey(RegexOptions options)
{
if ((options & RegexOptions.CultureInvariant) != 0)
{
return "";
}

return CultureInfo.CurrentCulture.ToString();
}

static Regex? Get(Key key)
{
long lastAccessedStamp = 0;
Expand Down Expand Up @@ -176,12 +205,14 @@ static void Add(Key key, Regex regex)
internal readonly struct Key : IEquatable<Key>
{
readonly string _pattern;
readonly string _culture;
readonly RegexOptions _options;
readonly TimeSpan _matchTimeout;

public Key(string pattern, RegexOptions options, TimeSpan matchTimeout)
public Key(string pattern, string culture, RegexOptions options, TimeSpan matchTimeout)
{
_pattern = pattern;
_culture = culture;
_options = options;
_matchTimeout = matchTimeout;
}
Expand All @@ -191,6 +222,7 @@ public override bool Equals([NotNullWhen(true)] object? obj) =>

public bool Equals(Key other) =>
_pattern.Equals(other._pattern) &&
_culture.Equals(other._culture) &&
_options == other._options &&
_matchTimeout == other._matchTimeout;

Expand Down
18 changes: 9 additions & 9 deletions src/Polyfill/Regex/RegexPolyfill.cs
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Expand Up @@ -24,21 +24,21 @@ static partial class Polyfill
/// </summary>
//Link: https://learn.microsoft.com/en-us/dotnet/api/system.text.regularexpressions.regex.count?view=net-11.0#system-text-regularexpressions-regex-count(system-string-system-string)
public static int Count(string input, string pattern) =>
new Regex(pattern).Count(input);
RegexCache.GetOrAdd(pattern).Count(input);

/// <summary>
/// Searches an input string for all occurrences of a regular expression and returns the number of matches.
/// </summary>
//Link: https://learn.microsoft.com/en-us/dotnet/api/system.text.regularexpressions.regex.count?view=net-11.0#system-text-regularexpressions-regex-count(system-string-system-string-system-text-regularexpressions-regexoptions)
public static int Count(string input, string pattern, RegexOptions options) =>
new Regex(pattern, options).Count(input);
RegexCache.GetOrAdd(pattern, options).Count(input);

/// <summary>
/// Searches an input string for all occurrences of a regular expression and returns the number of matches.
/// </summary>
//Link: https://learn.microsoft.com/en-us/dotnet/api/system.text.regularexpressions.regex.count?view=net-11.0#system-text-regularexpressions-regex-count(system-string-system-string-system-text-regularexpressions-regexoptions-system-timespan)
public static int Count(string input, string pattern, RegexOptions options, TimeSpan matchTimeout) =>
new Regex(pattern, options, matchTimeout).Count(input);
RegexCache.GetOrAdd(pattern, options, matchTimeout).Count(input);

#endif

Expand All @@ -49,21 +49,21 @@ public static int Count(string input, string pattern, RegexOptions options, Time
/// </summary>
//Link: https://learn.microsoft.com/en-us/dotnet/api/system.text.regularexpressions.regex.count?view=net-11.0#system-text-regularexpressions-regex-count(system-readonlyspan((system-char))-system-string)
public static int Count(ReadOnlySpan<char> input, string pattern) =>
new Regex(pattern).Count(input);
RegexCache.GetOrAdd(pattern).Count(input);

/// <summary>
/// Searches an input span for all occurrences of a regular expression and returns the number of matches.
/// </summary>
//Link: https://learn.microsoft.com/en-us/dotnet/api/system.text.regularexpressions.regex.count?view=net-11.0#system-text-regularexpressions-regex-count(system-readonlyspan((system-char))-system-string-system-text-regularexpressions-regexoptions)
public static int Count(ReadOnlySpan<char> input, string pattern, RegexOptions options) =>
new Regex(pattern, options).Count(input);
RegexCache.GetOrAdd(pattern, options).Count(input);

/// <summary>
/// Searches an input span for all occurrences of a regular expression and returns the number of matches.
/// </summary>
//Link: https://learn.microsoft.com/en-us/dotnet/api/system.text.regularexpressions.regex.count?view=net-11.0#system-text-regularexpressions-regex-count(system-readonlyspan((system-char))-system-string-system-text-regularexpressions-regexoptions-system-timespan)
public static int Count(ReadOnlySpan<char> input, string pattern, RegexOptions options, TimeSpan matchTimeout) =>
new Regex(pattern, options, matchTimeout).Count(input);
RegexCache.GetOrAdd(pattern, options, matchTimeout).Count(input);

/// <summary>
/// Indicates whether the specified regular expression finds a match in the specified input span, using the specified matching options and time-out interval.
Expand Down Expand Up @@ -114,21 +114,21 @@ public static ValueMatchEnumerator EnumerateMatches(ReadOnlySpan<char> input, st
//Link: https://learn.microsoft.com/en-us/dotnet/api/system.text.regularexpressions.regex.enumeratesplits?view=net-11.0#system-text-regularexpressions-regex-enumeratesplits(system-readonlyspan((system-char))-system-string)
public static ValueSplitEnumerator EnumerateSplits(ReadOnlySpan<char> input, string pattern)
{
var regex = new Regex(pattern);
var regex = RegexCache.GetOrAdd(pattern);
return new ValueSplitEnumerator(input, regex, 0);
}

//Link: https://learn.microsoft.com/en-us/dotnet/api/system.text.regularexpressions.regex.enumeratesplits?view=net-11.0#system-text-regularexpressions-regex-enumeratesplits(system-readonlyspan((system-char))-system-string-system-text-regularexpressions-regexoptions)
public static ValueSplitEnumerator EnumerateSplits(ReadOnlySpan<char> input, string pattern, RegexOptions options)
{
var regex = new Regex(pattern, options);
var regex = RegexCache.GetOrAdd(pattern, options);
return new ValueSplitEnumerator(input, regex, 0);
}

//Link: https://learn.microsoft.com/en-us/dotnet/api/system.text.regularexpressions.regex.enumeratesplits?view=net-11.0#system-text-regularexpressions-regex-enumeratesplits(system-readonlyspan((system-char))-system-string-system-text-regularexpressions-regexoptions-system-timespan)
public static ValueSplitEnumerator EnumerateSplits(ReadOnlySpan<char> input, string pattern, RegexOptions options, TimeSpan matchTimeout)
{
var regex = new Regex(pattern, options, matchTimeout);
var regex = RegexCache.GetOrAdd(pattern, options, matchTimeout);
return new ValueSplitEnumerator(input, regex, 0);
}

Expand Down
37 changes: 29 additions & 8 deletions src/Split/net461/Regex/RegexCache.cs
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@@ -1,20 +1,20 @@
// <auto-generated />
#pragma warning disable
#if FeatureMemory
#nullable enable
namespace System.Text.RegularExpressions;
using System;
using System.Collections.Concurrent;
using System.Collections.Generic;
using System.Diagnostics.CodeAnalysis;
using System.Diagnostics;
using System.Globalization;
using System.Threading;
/// <summary>Cache used to store Regex instances used by the static methods on Regex.</summary>
[ExcludeFromCodeCoverage]
[DebuggerNonUserCode]
#if PolyUseEmbeddedAttribute
[global::Microsoft.CodeAnalysis.EmbeddedAttribute]
#endif
/// <summary>Cache used to store Regex instances used by the static methods on Regex.</summary>
internal sealed class RegexCache
{
const int DefaultMaxCacheSize = 15;
Expand Down Expand Up @@ -58,20 +58,31 @@ public static int MaxCacheSize
}
}
}
public static Regex GetOrAdd(string pattern)
static readonly TimeSpan s_defaultTimeoutKey = TimeSpan.MinValue;
public static Regex GetOrAdd(string pattern) =>
GetOrAdd(pattern, RegexOptions.None);
public static Regex GetOrAdd(string pattern, RegexOptions options)
{
var key = new Key(pattern, RegexOptions.None, Regex.InfiniteMatchTimeout);
if (pattern is null)
{
throw new ArgumentNullException(nameof(pattern));
}
var key = new Key(pattern, GetCultureKey(options), options, s_defaultTimeoutKey);
var regex = Get(key);
if (regex is null)
{
regex = new Regex(pattern);
regex = new Regex(pattern, options);
Add(key, regex);
}
return regex;
}
public static Regex GetOrAdd(string pattern, RegexOptions options, TimeSpan matchTimeout)
{
Key key = new Key(pattern, options, matchTimeout);
if (pattern is null)
{
throw new ArgumentNullException(nameof(pattern));
}
Key key = new Key(pattern, GetCultureKey(options), options, matchTimeout);
Regex? regex = Get(key);
if (regex is null)
{
Expand All @@ -80,6 +91,14 @@ public static Regex GetOrAdd(string pattern, RegexOptions options, TimeSpan matc
}
return regex;
}
static string GetCultureKey(RegexOptions options)
{
if ((options & RegexOptions.CultureInvariant) != 0)
{
return "";
}
return CultureInfo.CurrentCulture.ToString();
}
static Regex? Get(Key key)
{
long lastAccessedStamp = 0;
Expand Down Expand Up @@ -147,18 +166,21 @@ static void Add(Key key, Regex regex)
internal readonly struct Key : IEquatable<Key>
{
readonly string _pattern;
readonly string _culture;
readonly RegexOptions _options;
readonly TimeSpan _matchTimeout;
public Key(string pattern, RegexOptions options, TimeSpan matchTimeout)
public Key(string pattern, string culture, RegexOptions options, TimeSpan matchTimeout)
{
_pattern = pattern;
_culture = culture;
_options = options;
_matchTimeout = matchTimeout;
}
public override bool Equals([NotNullWhen(true)] object? obj) =>
obj is Key other && Equals(other);
public bool Equals(Key other) =>
_pattern.Equals(other._pattern) &&
_culture.Equals(other._culture) &&
_options == other._options &&
_matchTimeout == other._matchTimeout;
public override int GetHashCode() =>
Expand All @@ -175,4 +197,3 @@ sealed class Node(Key key, Regex regex)
public long LastAccessStamp;
}
}
#endif
18 changes: 9 additions & 9 deletions src/Split/net461/Regex/RegexPolyfill.cs
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Expand Up @@ -16,33 +16,33 @@ static partial class Polyfill
/// Searches an input string for all occurrences of a regular expression and returns the number of matches.
/// </summary>
public static int Count(string input, string pattern) =>
new Regex(pattern).Count(input);
RegexCache.GetOrAdd(pattern).Count(input);
/// <summary>
/// Searches an input string for all occurrences of a regular expression and returns the number of matches.
/// </summary>
public static int Count(string input, string pattern, RegexOptions options) =>
new Regex(pattern, options).Count(input);
RegexCache.GetOrAdd(pattern, options).Count(input);
/// <summary>
/// Searches an input string for all occurrences of a regular expression and returns the number of matches.
/// </summary>
public static int Count(string input, string pattern, RegexOptions options, TimeSpan matchTimeout) =>
new Regex(pattern, options, matchTimeout).Count(input);
RegexCache.GetOrAdd(pattern, options, matchTimeout).Count(input);
#if FeatureMemory
/// <summary>
/// Searches an input span for all occurrences of a regular expression and returns the number of matches.
/// </summary>
public static int Count(ReadOnlySpan<char> input, string pattern) =>
new Regex(pattern).Count(input);
RegexCache.GetOrAdd(pattern).Count(input);
/// <summary>
/// Searches an input span for all occurrences of a regular expression and returns the number of matches.
/// </summary>
public static int Count(ReadOnlySpan<char> input, string pattern, RegexOptions options) =>
new Regex(pattern, options).Count(input);
RegexCache.GetOrAdd(pattern, options).Count(input);
/// <summary>
/// Searches an input span for all occurrences of a regular expression and returns the number of matches.
/// </summary>
public static int Count(ReadOnlySpan<char> input, string pattern, RegexOptions options, TimeSpan matchTimeout) =>
new Regex(pattern, options, matchTimeout).Count(input);
RegexCache.GetOrAdd(pattern, options, matchTimeout).Count(input);
/// <summary>
/// Indicates whether the specified regular expression finds a match in the specified input span, using the specified matching options and time-out interval.
/// </summary>
Expand Down Expand Up @@ -77,17 +77,17 @@ public static ValueMatchEnumerator EnumerateMatches(ReadOnlySpan<char> input, st
#if FeatureMemory && FeatureValueTuple
public static ValueSplitEnumerator EnumerateSplits(ReadOnlySpan<char> input, string pattern)
{
var regex = new Regex(pattern);
var regex = RegexCache.GetOrAdd(pattern);
return new ValueSplitEnumerator(input, regex, 0);
}
public static ValueSplitEnumerator EnumerateSplits(ReadOnlySpan<char> input, string pattern, RegexOptions options)
{
var regex = new Regex(pattern, options);
var regex = RegexCache.GetOrAdd(pattern, options);
return new ValueSplitEnumerator(input, regex, 0);
}
public static ValueSplitEnumerator EnumerateSplits(ReadOnlySpan<char> input, string pattern, RegexOptions options, TimeSpan matchTimeout)
{
var regex = new Regex(pattern, options, matchTimeout);
var regex = RegexCache.GetOrAdd(pattern, options, matchTimeout);
return new ValueSplitEnumerator(input, regex, 0);
}
#endif
Expand Down
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