[Text] [Optimization] [Alloc] Bidi Pooling

src/Avalonia.Base/Media/TextFormatting/TextFormatterImpl.cs

@@ -159,7 +159,7 @@ namespace Avalonia.Media.TextFormatting
         {
             var flowDirection = paragraphProperties.FlowDirection;
             var drawableTextRuns = new List<DrawableTextRun>();
-            var biDiData = new BidiData((sbyte)flowDirection);
+            using var biDiData = new BidiData((sbyte)flowDirection);
 
             foreach (var textRun in textRuns)
             {
@@ -177,7 +177,7 @@ namespace Avalonia.Media.TextFormatting
                 }
             }
 
-            var biDi = new BidiAlgorithm();
+            using var biDi = new BidiAlgorithm();
 
             biDi.Process(biDiData);
 

src/Avalonia.Base/Media/TextFormatting/Unicode/BiDiAlgorithm.cs

@@ -27,7 +27,7 @@ namespace Avalonia.Media.TextFormatting.Unicode
     /// as much as possible.
     /// </para>
     /// </remarks>
-    internal sealed class BidiAlgorithm
+    internal sealed class BidiAlgorithm : IDisposable
     {
         /// <summary>
         /// The original BiDiClass classes as provided by the caller
@@ -1714,5 +1714,13 @@ namespace Avalonia.Media.TextFormatting.Unicode
 
             public BidiClass Eos { get; }
         }
+
+        public void Dispose()
+        {
+            _workingClassesBuffer.Dispose();
+            _resolvedLevelsBuffer.Dispose();
+            _x9Map.Dispose();
+            _isolatedRunMapping.Dispose();
+        }
     }
 }

src/Avalonia.Base/Media/TextFormatting/Unicode/BiDiData.cs

@@ -11,7 +11,7 @@ namespace Avalonia.Media.TextFormatting.Unicode
     /// Represents a unicode string and all associated attributes
     /// for each character required for the bidirectional Unicode algorithm
     /// </summary>
-    internal class BidiData
+    internal class BidiData : IDisposable
     {
         private ArrayBuilder<BidiClass> _classes;
         private ArrayBuilder<BidiPairedBracketType> _pairedBracketTypes;
@@ -181,5 +181,15 @@ namespace Avalonia.Media.TextFormatting.Unicode
             
             return _tempLevelBuffer.Add(length, false);
         }
+
+        public void Dispose()
+        {
+            _classes.Dispose();
+            _pairedBracketTypes.Dispose();
+            _pairedBracketValues.Dispose();
+            _savedClasses.Dispose();
+            _savedPairedBracketTypes.Dispose();
+            _tempLevelBuffer.Dispose();
+        }
     }
 }

src/Avalonia.Base/Utilities/ArrayBuilder.cs

@@ -3,6 +3,7 @@
 // Ported from: https://github.com/SixLabors/Fonts/
 
 using System;
+using System.Buffers;
 using System.Runtime.CompilerServices;
 
 namespace Avalonia.Utilities
@@ -11,7 +12,7 @@ namespace Avalonia.Utilities
     /// A helper type for avoiding allocations while building arrays.
     /// </summary>
     /// <typeparam name="T">The type of item contained in the array.</typeparam>
-    internal struct ArrayBuilder<T>
+    internal struct ArrayBuilder<T> : IDisposable
         where T : struct
     {
         private const int DefaultCapacity = 4;
@@ -135,7 +136,7 @@ namespace Avalonia.Utilities
             }
 
             // Same expansion algorithm as List<T>.
-            var newCapacity = length == 0 ? DefaultCapacity : (uint)length * 2u;
+            var newCapacity = length == 0 ? DefaultCapacity : length * 2;
 
             if (newCapacity > MaxCoreClrArrayLength)
             {
@@ -144,10 +145,11 @@ namespace Avalonia.Utilities
 
             if (newCapacity < min)
             {
-                newCapacity = (uint)min;
+                newCapacity = min;
             }
 
-            var array = new T[newCapacity];
+            Dispose();
+            var array = ArrayPool<T>.Shared.Rent(newCapacity);
 
             if (_size > 0)
             {
@@ -180,5 +182,13 @@ namespace Avalonia.Utilities
         /// <returns>The <see cref="ArraySlice{T}"/>.</returns>
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
         public ArraySlice<T> AsSlice(int start, int length) => new ArraySlice<T>(_data!, start, length);
+        
+        public void Dispose()
+        {
+            if (_data != null)
+            {
+                ArrayPool<T>.Shared.Return(_data);
+            }
+        }
     }
 }