Revert optimization for RendererBase to use a plain type for the dictionary key (#632)

Don't try to use the MT pointer on unsupported platforms

src/Markdig.Tests/TestContainerBlocks.cs

@@ -88,5 +88,102 @@ namespace Markdig.Tests
 
             Assert.Throws<ArgumentException>(() => container[0] = two); // two already has a parent
         }
+
+        [Test]
+        public void Contains()
+        {
+            var container = new MockContainerBlock();
+            var block = new ParagraphBlock();
+
+            Assert.False(container.Contains(block));
+
+            container.Add(block);
+            Assert.True(container.Contains(block));
+
+            container.Add(new ParagraphBlock());
+            Assert.True(container.Contains(block));
+
+            container.Insert(0, new ParagraphBlock());
+            Assert.True(container.Contains(block));
+        }
+
+        [Test]
+        public void Remove()
+        {
+            var container = new MockContainerBlock();
+            var block = new ParagraphBlock();
+
+            Assert.False(container.Remove(block));
+            Assert.AreEqual(0, container.Count);
+            Assert.Throws<ArgumentOutOfRangeException>(() => container.RemoveAt(0));
+            Assert.AreEqual(0, container.Count);
+
+            container.Add(block);
+            Assert.AreEqual(1, container.Count);
+            Assert.True(container.Remove(block));
+            Assert.AreEqual(0, container.Count);
+            Assert.False(container.Remove(block));
+            Assert.AreEqual(0, container.Count);
+
+            container.Add(block);
+            Assert.AreEqual(1, container.Count);
+            container.RemoveAt(0);
+            Assert.AreEqual(0, container.Count);
+            Assert.Throws<ArgumentOutOfRangeException>(() => container.RemoveAt(0));
+            Assert.AreEqual(0, container.Count);
+
+            container.Add(new ParagraphBlock { Column = 1 });
+            container.Add(new ParagraphBlock { Column = 2 });
+            container.Add(new ParagraphBlock { Column = 3 });
+            container.Add(new ParagraphBlock { Column = 4 });
+            Assert.AreEqual(4, container.Count);
+
+            container.RemoveAt(2);
+            Assert.AreEqual(3, container.Count);
+            Assert.AreEqual(4, container[2].Column);
+
+            Assert.True(container.Remove(container[1]));
+            Assert.AreEqual(2, container.Count);
+            Assert.AreEqual(1, container[0].Column);
+            Assert.AreEqual(4, container[1].Column);
+            Assert.Throws<IndexOutOfRangeException>(() => _ = container[2]);
+        }
+
+        [Test]
+        public void CopyTo()
+        {
+            var container = new MockContainerBlock();
+
+            var destination = new Block[4];
+            container.CopyTo(destination, 0);
+            container.CopyTo(destination, 1);
+            container.CopyTo(destination, -1);
+            container.CopyTo(destination, 5);
+            Assert.Null(destination[0]);
+
+            container.Add(new ParagraphBlock());
+            container.CopyTo(destination, 0);
+            Assert.NotNull(destination[0]);
+            Assert.Null(destination[1]);
+            Assert.Null(destination[2]);
+            Assert.Null(destination[3]);
+
+            container.CopyTo(destination, 2);
+            Assert.NotNull(destination[0]);
+            Assert.Null(destination[1]);
+            Assert.NotNull(destination[2]);
+            Assert.Null(destination[3]);
+
+            Array.Clear(destination);
+
+            container.Add(new ParagraphBlock());
+            container.CopyTo(destination, 1);
+            Assert.Null(destination[0]);
+            Assert.NotNull(destination[1]);
+            Assert.NotNull(destination[2]);
+            Assert.Null(destination[3]);
+
+            Assert.Throws<IndexOutOfRangeException>(() => container.CopyTo(destination, 3));
+        }
     }
 }

src/Markdig/Renderers/RendererBase.cs

@@ -4,7 +4,9 @@
 
 using System;
 using System.Collections.Generic;
+using System.Diagnostics;
 using System.Runtime.CompilerServices;
+using System.Runtime.InteropServices;
 using Markdig.Helpers;
 using Markdig.Syntax;
 using Markdig.Syntax.Inlines;
@@ -17,20 +19,7 @@ namespace Markdig.Renderers
     /// <seealso cref="IMarkdownRenderer" />
     public abstract class RendererBase : IMarkdownRenderer
     {
-        private readonly struct KeyWrapper : IEquatable<KeyWrapper>
-        {
-            public readonly IntPtr Key;
-
-            public KeyWrapper(IntPtr key) => Key = key;
-
-            public bool Equals(KeyWrapper other) => Key == other.Key;
-
-            public override int GetHashCode() => Key.GetHashCode();
-
-            public override bool Equals(object? obj) => throw new NotImplementedException();
-        }
-
-        private readonly Dictionary<KeyWrapper, IMarkdownObjectRenderer?> _renderersPerType = new();
+        private readonly Dictionary<Type, IMarkdownObjectRenderer?> _renderersPerType = new();
         internal int _childrenDepth = 0;
 
         /// <summary>
@@ -40,13 +29,11 @@ namespace Markdig.Renderers
 
         private IMarkdownObjectRenderer? GetRendererInstance(MarkdownObject obj)
         {
-            KeyWrapper key = GetKeyForType(obj);
-            Type objectType = obj.GetType();
-
+            var key = obj.GetType();
             for (int i = 0; i < ObjectRenderers.Count; i++)
             {
                 var renderer = ObjectRenderers[i];
-                if (renderer.Accept(this, objectType))
+                if (renderer.Accept(this, key))
                 {
                     _renderersPerType[key] = renderer;
                     return renderer;
@@ -154,7 +141,7 @@ namespace Markdig.Renderers
             // Calls before writing an object
             ObjectWriteBefore?.Invoke(this, obj);
 
-            if (!_renderersPerType.TryGetValue(GetKeyForType(obj), out IMarkdownObjectRenderer? renderer))
+            if (!_renderersPerType.TryGetValue(obj.GetType(), out IMarkdownObjectRenderer? renderer))
             {
                 renderer = GetRendererInstance(obj);
             }
@@ -175,22 +162,5 @@ namespace Markdig.Renderers
             // Calls after writing an object
             ObjectWriteAfter?.Invoke(this, obj);
         }
-
-        [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        private static KeyWrapper GetKeyForType(MarkdownObject obj)
-        {
-#if NET
-            IntPtr methodTablePtr = Unsafe.Add(ref Unsafe.As<RawData>(obj).Data, -1);
-            return new KeyWrapper(methodTablePtr);
-#else
-            IntPtr typeHandle = Type.GetTypeHandle(obj).Value;
-            return new KeyWrapper(typeHandle);
-#endif
-        }
-
-        private sealed class RawData
-        {
-            public IntPtr Data;
-        }
     }
 }

src/Markdig/Syntax/ContainerBlock.cs

@@ -130,7 +130,7 @@ namespace Markdig.Syntax
             BlockWrapper[] children = _children;
             for (int i = 0; i < Count && i < children.Length; i++)
             {
-                array[arrayIndex + 1] = children[i].Block;
+                array[arrayIndex + i] = children[i].Block;
             }
         }
 
@@ -193,7 +193,7 @@ namespace Markdig.Syntax
 
         public void RemoveAt(int index)
         {
-            if ((uint)index > (uint)Count)
+            if ((uint)index >= (uint)Count)
                 ThrowHelper.ArgumentOutOfRangeException_index();
 
             Count--;