Use pooled memory for memory copies performed by `ZipArchiveReader`

osu.Game/IO/Archives/ZipArchiveReader.cs

@@ -1,11 +1,15 @@
 // Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
 // See the LICENCE file in the repository root for full licence text.
 
+using System.Buffers;
 using System.Collections.Generic;
 using System.IO;
 using System.Linq;
+using Microsoft.Toolkit.HighPerformance;
+using osu.Framework.Extensions;
 using osu.Framework.IO.Stores;
 using SharpCompress.Archives.Zip;
+using SixLabors.ImageSharp.Memory;
 
 namespace osu.Game.IO.Archives
 {
@@ -27,15 +31,12 @@ public override Stream GetStream(string name)
             if (entry == null)
                 throw new FileNotFoundException();
 
-            // allow seeking
-            MemoryStream copy = new MemoryStream();
+            var owner = MemoryAllocator.Default.Allocate<byte>((int)entry.Size);
 
             using (Stream s = entry.OpenEntryStream())
-                s.CopyTo(copy);
+                s.ReadToFill(owner.Memory.Span);
 
-            copy.Position = 0;
-
-            return copy;
+            return new MemoryOwnerMemoryStream(owner);
         }
 
         public override void Dispose()
@@ -45,5 +46,48 @@ public override void Dispose()
         }
 
         public override IEnumerable<string> Filenames => archive.Entries.Select(e => e.Key).ExcludeSystemFileNames();
+
+        private class MemoryOwnerMemoryStream : Stream
+        {
+            private readonly IMemoryOwner<byte> owner;
+            private readonly Stream stream;
+
+            public MemoryOwnerMemoryStream(IMemoryOwner<byte> owner)
+            {
+                this.owner = owner;
+
+                stream = owner.Memory.AsStream();
+            }
+
+            protected override void Dispose(bool disposing)
+            {
+                owner?.Dispose();
+                base.Dispose(disposing);
+            }
+
+            public override void Flush() => stream.Flush();
+
+            public override int Read(byte[] buffer, int offset, int count) => stream.Read(buffer, offset, count);
+
+            public override long Seek(long offset, SeekOrigin origin) => stream.Seek(offset, origin);
+
+            public override void SetLength(long value) => stream.SetLength(value);
+
+            public override void Write(byte[] buffer, int offset, int count) => stream.Write(buffer, offset, count);
+
+            public override bool CanRead => stream.CanRead;
+
+            public override bool CanSeek => stream.CanSeek;
+
+            public override bool CanWrite => stream.CanWrite;
+
+            public override long Length => stream.Length;
+
+            public override long Position
+            {
+                get => stream.Position;
+                set => stream.Position = value;
+            }
+        }
     }
 }

osu.Game/osu.Game.csproj

@@ -29,6 +29,7 @@
     <PackageReference Include="Microsoft.EntityFrameworkCore.Sqlite" Version="5.0.14" />
     <PackageReference Include="Microsoft.EntityFrameworkCore.Sqlite.Core" Version="5.0.14" />
     <PackageReference Include="Microsoft.Extensions.Configuration.Abstractions" Version="6.0.0" />
+    <PackageReference Include="Microsoft.Toolkit.HighPerformance" Version="7.1.2" />
     <PackageReference Include="Newtonsoft.Json" Version="13.0.1" />
     <PackageReference Include="ppy.LocalisationAnalyser" Version="2022.417.0">
       <PrivateAssets>all</PrivateAssets>