Merge pull request #377 from MihaZupan/allocation-reductions

10% time and 50% memory improvement
xoofx · Oct 15, 2019 · 07a7714 · 07a7714
2 parents f8ab1cc + 3606f23
commit 07a7714
Show file tree

Hide file tree

Showing 28 changed files with 567 additions and 309 deletions.
diff --git a/appveyor.yml b/appveyor.yml
@@ -1,5 +1,5 @@
 version: 10.0.{build}
-image: Visual Studio 2017
+image: Visual Studio 2019
 configuration: Release
 environment:
   COVERALLS_REPO_TOKEN:

diff --git a/changelog.md b/changelog.md
@@ -5,6 +5,7 @@
 - Fix SmartyPants quote matching ([(PR #360)](https://github.com/lunet-io/markdig/pull/360))
 - Fix generic attributes with values of length 1 ([(PR #361)](https://github.com/lunet-io/markdig/pull/361))
 - Fix link text balanced bracket matching ([(PR #375)](https://github.com/lunet-io/markdig/pull/375))
+- Improve overall performance and substantially reduce allocations ([(PR #377)](https://github.com/lunet-io/markdig/pull/377))
 
 ## 0.17.1 (04 July 2019)
 - Fix regression when escaping HTML characters ([(PR #340)](https://github.com/lunet-io/markdig/pull/340))

diff --git a/src/Markdig.Tests/TestStringSliceList.cs b/src/Markdig.Tests/TestStringSliceList.cs
@@ -1,4 +1,4 @@
-using NUnit.Framework;
+using NUnit.Framework;
 using System.Collections.Generic;
 using System.Text;
 using Markdig.Helpers;
@@ -81,8 +81,18 @@ public void TestStringLineGroupSaveAndRestore()
         public void TestSkipWhitespaces()
         {
             var text = new StringLineGroup("             ABC").ToCharIterator();
-            Assert.True(text.TrimStart());
+            Assert.False(text.TrimStart());
             Assert.AreEqual('A', text.CurrentChar);
+
+            text = new StringLineGroup("        ").ToCharIterator();
+            Assert.True(text.TrimStart());
+            Assert.AreEqual('\0', text.CurrentChar);
+
+            var slice = new StringSlice("             ABC");
+            Assert.False(slice.TrimStart());
+
+            slice = new StringSlice("        ");
+            Assert.True(slice.TrimStart());
         }
 
         [Test]

diff --git a/src/Markdig/Extensions/AutoIdentifiers/AutoIdentifierExtension.cs b/src/Markdig/Extensions/AutoIdentifiers/AutoIdentifierExtension.cs
@@ -22,6 +22,7 @@ public class AutoIdentifierExtension : IMarkdownExtension
     {
         private const string AutoIdentifierKey = "AutoIdentifier";
         private readonly AutoIdentifierOptions options;
+        private readonly StripRendererCache rendererCache = new StripRendererCache();
 
         /// <summary>
         /// Initializes a new instance of the <see cref="AutoIdentifierExtension"/> class.
@@ -159,17 +160,11 @@ private void HeadingBlock_ProcessInlinesEnd(InlineProcessor processor, Inline in
             }
 
             // Use internally a HtmlRenderer to strip links from a heading
-            var headingWriter = new StringWriter();
-            var stripRenderer = new HtmlRenderer(headingWriter)
-            {
-                // Set to false both to avoid having any HTML tags in the output
-                EnableHtmlForInline = false,
-                EnableHtmlEscape = false
-            };
+            var stripRenderer = rendererCache.Get();
 
             stripRenderer.Render(headingBlock.Inline);
-            var headingText = headingWriter.ToString();
-            headingWriter.GetStringBuilder().Length = 0;
+            var headingText = stripRenderer.Writer.ToString();
+            rendererCache.Release(stripRenderer);
 
             // Urilize the link
             headingText = (options & AutoIdentifierOptions.GitHub) != 0
@@ -195,5 +190,25 @@ private void HeadingBlock_ProcessInlinesEnd(InlineProcessor processor, Inline in
 
             attributes.Id = headingId;
         }
+
+        private sealed class StripRendererCache : ObjectCache<HtmlRenderer>
+        {
+            protected override HtmlRenderer NewInstance()
+            {
+                var headingWriter = new StringWriter();
+                var stripRenderer = new HtmlRenderer(headingWriter)
+                {
+                    // Set to false both to avoid having any HTML tags in the output
+                    EnableHtmlForInline = false,
+                    EnableHtmlEscape = false
+                };
+                return stripRenderer;
+            }
+
+            protected override void Reset(HtmlRenderer instance)
+            {
+                instance.Reset();
+            }
+        }
     }
 }