.NET 8.0 and a few other perf improvements

.github/workflows/ci.yml

@@ -20,10 +20,13 @@ jobs:
         submodules: true
         fetch-depth: 0
 
-    - name: Install .NET 6.0
+    - name: Install .NET 6.0, 7.0, and 8.0
       uses: actions/setup-dotnet@v1
       with:
-        dotnet-version: '6.0.x'
+        dotnet-version: |
+          6.0.x
+          7.0.x
+          8.0.x
 
     - name: Build, Test, Pack, Publish
       shell: bash

src/Markdig.Tests/Markdig.Tests.csproj

@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFramework>net6.0</TargetFramework>
+    <TargetFrameworks>net6.0;net8.0</TargetFrameworks>
     <OutputType>Exe</OutputType>
     <IsPackable>false</IsPackable>
     <ImplicitUsings>enable</ImplicitUsings>

src/Markdig.Tests/TestYamlFrontMatterExtension.cs

@@ -75,8 +75,11 @@ public DummyRenderer()
             ObjectRenderers = new ObjectRendererCollection();
         }
 
+#pragma warning disable CS0067 // ObjectWriteBefore/ObjectWriteAfter is never used
         public event Action<IMarkdownRenderer, MarkdownObject> ObjectWriteBefore;
         public event Action<IMarkdownRenderer, MarkdownObject> ObjectWriteAfter;
+#pragma warning restore CS0067
+
         public ObjectRendererCollection ObjectRenderers { get; }
         public object Render(MarkdownObject markdownObject)
         {

src/Markdig/Extensions/AutoIdentifiers/AutoIdentifierExtension.cs

@@ -20,16 +20,18 @@ namespace Markdig.Extensions.AutoIdentifiers;
 public class AutoIdentifierExtension : IMarkdownExtension
 {
     private const string AutoIdentifierKey = "AutoIdentifier";
-    private readonly AutoIdentifierOptions options;
-    private readonly StripRendererCache rendererCache = new StripRendererCache();
+
+    private static readonly StripRendererCache _rendererCache = new();
+
+    private readonly AutoIdentifierOptions _options;
 
     /// <summary>
     /// Initializes a new instance of the <see cref="AutoIdentifierExtension"/> class.
     /// </summary>
     /// <param name="options">The options.</param>
     public AutoIdentifierExtension(AutoIdentifierOptions options)
     {
-        this.options = options;
+        _options = options;
     }
 
     public void Setup(MarkdownPipelineBuilder pipeline)
@@ -68,7 +70,7 @@ private void HeadingBlockParser_Closed(BlockProcessor processor, Block block)
         }
 
         // If the AutoLink options is set, we register a LinkReferenceDefinition at the document level
-        if ((options & AutoIdentifierOptions.AutoLink) != 0)
+        if ((_options & AutoIdentifierOptions.AutoLink) != 0)
         {
             var headingLine = headingBlock.Lines.Lines[0];
 
@@ -157,16 +159,17 @@ private void HeadingBlock_ProcessInlinesEnd(InlineProcessor processor, Inline? i
         }
 
         // Use internally a HtmlRenderer to strip links from a heading
-        var stripRenderer = rendererCache.Get();
+        var stripRenderer = _rendererCache.Get();
 
         stripRenderer.Render(headingBlock.Inline);
-        var headingText = stripRenderer.Writer.ToString()!;
-        rendererCache.Release(stripRenderer);
+        ReadOnlySpan<char> rawHeadingText = ((FastStringWriter)stripRenderer.Writer).AsSpan();
 
         // Urilize the link
-        headingText = (options & AutoIdentifierOptions.GitHub) != 0
-            ? LinkHelper.UrilizeAsGfm(headingText)
-            : LinkHelper.Urilize(headingText, (options & AutoIdentifierOptions.AllowOnlyAscii) != 0);
+        string headingText = (_options & AutoIdentifierOptions.GitHub) != 0
+            ? LinkHelper.UrilizeAsGfm(rawHeadingText)
+            : LinkHelper.Urilize(rawHeadingText, (_options & AutoIdentifierOptions.AllowOnlyAscii) != 0);
+
+        _rendererCache.Release(stripRenderer);
 
         // If the heading is empty, use the word "section" instead
         var baseHeadingId = string.IsNullOrEmpty(headingText) ? "section" : headingText;
@@ -197,7 +200,7 @@ private sealed class StripRendererCache : ObjectCache<HtmlRenderer>
     {
         protected override HtmlRenderer NewInstance()
         {
-            var headingWriter = new StringWriter();
+            var headingWriter = new FastStringWriter();
             var stripRenderer = new HtmlRenderer(headingWriter)
             {
                 // Set to false both to avoid having any HTML tags in the output
@@ -209,7 +212,9 @@ protected override HtmlRenderer NewInstance()
 
         protected override void Reset(HtmlRenderer instance)
         {
-            instance.Reset();
+            instance.ResetInternal();
+
+            ((FastStringWriter)instance.Writer).Reset();
         }
     }
 }

src/Markdig/Helpers/BlockWrapper.cs

@@ -22,7 +22,7 @@ public BlockWrapper(Block block)
 
     public bool Equals(BlockWrapper other) => ReferenceEquals(Block, other.Block);
 
-    public override bool Equals(object obj) => Block.Equals(obj);
+    public override bool Equals(object? obj) => Block.Equals(obj);
 
     public override int GetHashCode() => Block.GetHashCode();
 }

src/Markdig/Helpers/CharHelper.cs

@@ -30,15 +30,17 @@ public static class CharHelper
         { 'I', 1 }, { 'V', 5 }, { 'X', 10 }
     };
 
-    private static readonly char[] punctuationExceptions = { '−', '-', '†', '‡' };
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    private static bool IsPunctuationException(char c) =>
+        c is '−' or '-' or '†' or '‡';
 
     public static void CheckOpenCloseDelimiter(char pc, char c, bool enableWithinWord, out bool canOpen, out bool canClose)
     {
         pc.CheckUnicodeCategory(out bool prevIsWhiteSpace, out bool prevIsPunctuation);
         c.CheckUnicodeCategory(out bool nextIsWhiteSpace, out bool nextIsPunctuation);
 
-        var prevIsExcepted = prevIsPunctuation && punctuationExceptions.Contains(pc);
-        var nextIsExcepted = nextIsPunctuation && punctuationExceptions.Contains(c);
+        var prevIsExcepted = prevIsPunctuation && IsPunctuationException(pc);
+        var nextIsExcepted = nextIsPunctuation && IsPunctuationException(c);
 
         // A left-flanking delimiter run is a delimiter run that is
         // (1) not followed by Unicode whitespace, and either
@@ -126,19 +128,6 @@ public static bool IsAcrossTab(int column)
         return (column & (TabSize - 1)) != 0;
     }
 
-    [MethodImpl(MethodImplOptions.AggressiveInlining)]
-    public static bool Contains(this char[] charList, char c)
-    {
-        foreach (char ch in charList)
-        {
-            if (ch == c)
-            {
-                return true;
-            }
-        }
-        return false;
-    }
-
     [MethodImpl(MethodImplOptions.AggressiveInlining)]
     public static bool IsWhitespace(this char c)
     {
@@ -178,7 +167,7 @@ static bool IsWhitespaceRare(char c)
     [MethodImpl(MethodImplOptions.AggressiveInlining)]
     public static bool IsControl(this char c)
     {
-        return c < ' ' || char.IsControl(c);
+        return char.IsControl(c);
     }
 
     [MethodImpl(MethodImplOptions.AggressiveInlining)]
@@ -211,15 +200,17 @@ public static void CheckUnicodeCategory(this char c, out bool space, out bool pu
         {
             // A Unicode punctuation character is an ASCII punctuation character
             // or anything in the general Unicode categories Pc, Pd, Pe, Pf, Pi, Po, or Ps.
+            const int PunctuationCategoryMask =
+                1 << (int)UnicodeCategory.ConnectorPunctuation |
+                1 << (int)UnicodeCategory.DashPunctuation |
+                1 << (int)UnicodeCategory.OpenPunctuation |
+                1 << (int)UnicodeCategory.ClosePunctuation |
+                1 << (int)UnicodeCategory.InitialQuotePunctuation |
+                1 << (int)UnicodeCategory.FinalQuotePunctuation |
+                1 << (int)UnicodeCategory.OtherPunctuation;
+
             space = false;
-            UnicodeCategory category = CharUnicodeInfo.GetUnicodeCategory(c);
-            punctuation = category == UnicodeCategory.ConnectorPunctuation
-                || category == UnicodeCategory.DashPunctuation
-                || category == UnicodeCategory.OpenPunctuation
-                || category == UnicodeCategory.ClosePunctuation
-                || category == UnicodeCategory.InitialQuotePunctuation
-                || category == UnicodeCategory.FinalQuotePunctuation
-                || category == UnicodeCategory.OtherPunctuation;
+            punctuation = (PunctuationCategoryMask & (1 << (int)CharUnicodeInfo.GetUnicodeCategory(c))) != 0;
         }
     }
 
@@ -236,14 +227,16 @@ internal static bool IsSpaceOrPunctuation(this char c)
         }
         else
         {
-            var category = CharUnicodeInfo.GetUnicodeCategory(c);
-            return category == UnicodeCategory.ConnectorPunctuation
-                || category == UnicodeCategory.DashPunctuation
-                || category == UnicodeCategory.OpenPunctuation
-                || category == UnicodeCategory.ClosePunctuation
-                || category == UnicodeCategory.InitialQuotePunctuation
-                || category == UnicodeCategory.FinalQuotePunctuation
-                || category == UnicodeCategory.OtherPunctuation;
+            const int PunctuationCategoryMask =
+                1 << (int)UnicodeCategory.ConnectorPunctuation |
+                1 << (int)UnicodeCategory.DashPunctuation |
+                1 << (int)UnicodeCategory.OpenPunctuation |
+                1 << (int)UnicodeCategory.ClosePunctuation |
+                1 << (int)UnicodeCategory.InitialQuotePunctuation |
+                1 << (int)UnicodeCategory.FinalQuotePunctuation |
+                1 << (int)UnicodeCategory.OtherPunctuation;
+
+            return (PunctuationCategoryMask & (1 << (int)CharUnicodeInfo.GetUnicodeCategory(c))) != 0;
         }
     }