Fix potential hang when parsing LinkReferenceDefinition (#278)

xoofx · Dec 28, 2018 · c3395e6 · c3395e6
1 parent cc47d33
commit c3395e6
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Showing 6 changed files with 38 additions and 13 deletions.
diff --git a/src/Markdig.Tests/Markdig.Tests.csproj b/src/Markdig.Tests/Markdig.Tests.csproj
@@ -76,6 +76,9 @@
   </ItemGroup>
   <ItemGroup>
     <None Include="App.config" />
+    <Content Include="hang.md">
+      <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
+    </Content>
     <None Include="project.json" />
     <None Include="Specs\GlobalizationSpecs.md" />
     <None Include="Specs\JiraLinks.md" />

diff --git a/src/Markdig.Tests/TestParser.cs b/src/Markdig.Tests/TestParser.cs
@@ -3,6 +3,7 @@
 // See the license.txt file in the project root for more information.
 using System;
 using System.Collections.Generic;
+using System.IO;
 using System.Text;
 using System.Text.RegularExpressions;
 using Markdig.Extensions.JiraLinks;
@@ -12,6 +13,13 @@ namespace Markdig.Tests
 {
     public class TestParser
     {
+        [Test]
+        public void TestFixHang()
+        {
+            var input = File.ReadAllText("hang.md");
+            var html = Markdown.ToHtml(input);
+        }
+
         [Test]
         public void TestEmphasisAndHtmlEntity()
         {

diff --git a/src/Markdig.Tests/hang.md b/src/Markdig.Tests/hang.md
diff --git a/src/Markdig/Helpers/StringLineGroup.cs b/src/Markdig/Helpers/StringLineGroup.cs
@@ -225,6 +225,30 @@ public Iterator(StringLineGroup lines)
 
             public int SliceIndex { get; private set; }
 
+            public StringLineGroup Remaining()
+            {
+                var lines = _lines;
+                if (CurrentChar == '\0')
+                {
+                    lines.Clear();
+                }
+                else
+                {
+                    for (int i = SliceIndex - 1; i >= 0; i--)
+                    {
+                        lines.RemoveAt(i);
+                    }
+
+                    if (lines.Lines.Length > 0)
+                    {
+                        lines.Lines[0].Column = _offset - lines.Lines[0].Slice.Start;
+                        lines.Lines[0].Slice.Start = _offset;
+                    }
+                }
+
+                return lines;
+            }
+
             public char NextChar()
             {
                 Start++;

diff --git a/src/Markdig/Parsers/ParagraphBlockParser.cs b/src/Markdig/Parsers/ParagraphBlockParser.cs
@@ -166,18 +166,7 @@ private bool TryMatchLinkReferenceDefinition(ref StringLineGroup lines, BlockPro
                     linkReferenceDefinition.UrlSpan     = linkReferenceDefinition.UrlSpan   .MoveForward(startPosition);
                     linkReferenceDefinition.TitleSpan   = linkReferenceDefinition.TitleSpan .MoveForward(startPosition);
 
-                    // Remove lines that have been matched
-                    if (iterator.Start > iterator.End)
-                    {
-                        lines.Clear();
-                    }
-                    else
-                    {
-                        for (int i = iterator.SliceIndex - 1; i >= 0; i--)
-                        {
-                            lines.RemoveAt(i);
-                        }
-                    }
+                    lines = iterator.Remaining();
                 }
                 else
                 {

diff --git a/src/markdig.sln.DotSettings b/src/markdig.sln.DotSettings
@@ -2,4 +2,5 @@
 	<s:String x:Key="/Default/CodeStyle/FileHeader/FileHeaderText/@EntryValue">Copyright (c) Alexandre Mutel. All rights reserved.&#xD;
 This file is licensed under the BSD-Clause 2 license. &#xD;
 See the license.txt file in the project root for more information.</s:String>
-	<s:String x:Key="/Default/CodeStyle/Naming/CSharpNaming/PredefinedNamingRules/=PrivateInstanceFields/@EntryIndexedValue">&lt;Policy Inspect="True" Prefix="" Suffix="" Style="aaBb" /&gt;</s:String></wpf:ResourceDictionary>
+	<s:String x:Key="/Default/CodeStyle/Naming/CSharpNaming/PredefinedNamingRules/=PrivateInstanceFields/@EntryIndexedValue">&lt;Policy Inspect="True" Prefix="" Suffix="" Style="aaBb" /&gt;</s:String>
+	<s:String x:Key="/Default/Environment/UnitTesting/NUnitProvider/SetCurrentDirectoryTo/@EntryValue">TestFolder</s:String></wpf:ResourceDictionary>