Texture loading: reduce memory allocations (#6623)

* rebase

* add methods Ryyjinx.Common EmbeddedResources and SteamUtils

* GAL changes - change SetData() methods and ThreadedTexture commands to use IMemoryOwner<byte> instead of SpanOrArray<byte>

* Ryujinx.Graphics.Texture: change texture conversion methods to return IMemoryOwner<byte> and allocate from ByteMemoryPool

* Ryujinx.Graphics.OpenGL: update ITexture and Texture-like types with SetData() methods to take IMemoryOwner<byte> instead of SpanOrArray<byte>

* Ryujinx.Graphics.Vulkan: update ITexture and Texture-like types with SetData() methods to take IMemoryOwner<byte> instead of SpanOrArray<byte>

* Ryujinx.Graphics.Gpu: update ITexture and Texture-like types with SetData() methods to take IMemoryOwner<byte> instead of SpanOrArray<byte>

* Remove now-unused SpanOrArray<T>

* post-rebase cleanup

* PixelConverter: remove unsafe modifier on safe methods, and remove one unnecessary cast

* use ByteMemoryPool.Rent() in GetWritableRegion() impls

* fix formatting, rename `ReadRentedMemory()` to `ReadFileToRentedMemory()``

* Texture.ConvertToHostCompatibleFormat(): dispose of `result` in Astc decode branch

3 files changed, 81 insertions, 92 deletions

diff --git a/src/Ryujinx.Common/Memory/SpanOrArray.cs b/src/Ryujinx.Common/Memory/SpanOrArray.cs
deleted file mode 100644
index 269ac02f..00000000
--- a/src/Ryujinx.Common/Memory/SpanOrArray.cs
+++ /dev/null
@@ -1,89 +0,0 @@
-using System;
-
-namespace Ryujinx.Common.Memory
-{
-    /// <summary>
-    /// A struct that can represent both a Span and Array.
-    /// This is useful to keep the Array representation when possible to avoid copies.
-    /// </summary>
-    /// <typeparam name="T">Element Type</typeparam>
-    public readonly ref struct SpanOrArray<T> where T : unmanaged
-    {
-        public readonly T[] Array;
-        public readonly ReadOnlySpan<T> Span;
-
-        /// <summary>
-        /// Create a new SpanOrArray from an array.
-        /// </summary>
-        /// <param name="array">Array to store</param>
-        public SpanOrArray(T[] array)
-        {
-            Array = array;
-            Span = ReadOnlySpan<T>.Empty;
-        }
-
-        /// <summary>
-        /// Create a new SpanOrArray from a readonly span.
-        /// </summary>
-        /// <param name="array">Span to store</param>
-        public SpanOrArray(ReadOnlySpan<T> span)
-        {
-            Array = null;
-            Span = span;
-        }
-
-        /// <summary>
-        /// Return the contained array, or convert the span if necessary.
-        /// </summary>
-        /// <returns>An array containing the data</returns>
-        public T[] ToArray()
-        {
-            return Array ?? Span.ToArray();
-        }
-
-        /// <summary>
-        /// Return a ReadOnlySpan from either the array or ReadOnlySpan.
-        /// </summary>
-        /// <returns>A ReadOnlySpan containing the data</returns>
-        public ReadOnlySpan<T> AsSpan()
-        {
-            return Array ?? Span;
-        }
-
-        /// <summary>
-        /// Cast an array to a SpanOrArray.
-        /// </summary>
-        /// <param name="array">Source array</param>
-        public static implicit operator SpanOrArray<T>(T[] array)
-        {
-            return new SpanOrArray<T>(array);
-        }
-
-        /// <summary>
-        /// Cast a ReadOnlySpan to a SpanOrArray.
-        /// </summary>
-        /// <param name="span">Source ReadOnlySpan</param>
-        public static implicit operator SpanOrArray<T>(ReadOnlySpan<T> span)
-        {
-            return new SpanOrArray<T>(span);
-        }
-
-        /// <summary>
-        /// Cast a Span to a SpanOrArray.
-        /// </summary>
-        /// <param name="span">Source Span</param>
-        public static implicit operator SpanOrArray<T>(Span<T> span)
-        {
-            return new SpanOrArray<T>(span);
-        }
-
-        /// <summary>
-        /// Cast a SpanOrArray to a ReadOnlySpan
-        /// </summary>
-        /// <param name="spanOrArray">Source SpanOrArray</param>
-        public static implicit operator ReadOnlySpan<T>(SpanOrArray<T> spanOrArray)
-        {
-            return spanOrArray.AsSpan();
-        }
-    }
-}
diff --git a/src/Ryujinx.Common/Utilities/EmbeddedResources.cs b/src/Ryujinx.Common/Utilities/EmbeddedResources.cs
index a4facc2e..e22571c9 100644
--- a/src/Ryujinx.Common/Utilities/EmbeddedResources.cs
+++ b/src/Ryujinx.Common/Utilities/EmbeddedResources.cs
@@ -1,5 +1,6 @@
 using Ryujinx.Common.Utilities;
 using System;
+using System.Buffers;
 using System.IO;
 using System.Linq;
 using System.Reflection;
@@ -41,6 +42,22 @@ namespace Ryujinx.Common
             return StreamUtils.StreamToBytes(stream);
         }
 
+        public static IMemoryOwner<byte> ReadFileToRentedMemory(string filename)
+        {
+            var (assembly, path) = ResolveManifestPath(filename);
+
+            return ReadFileToRentedMemory(assembly, path);
+        }
+
+        public static IMemoryOwner<byte> ReadFileToRentedMemory(Assembly assembly, string filename)
+        {
+            using var stream = GetStream(assembly, filename);
+
+            return stream is null
+                ? null
+                : StreamUtils.StreamToRentedMemory(stream);
+        }
+
         public async static Task<byte[]> ReadAsync(Assembly assembly, string filename)
         {
             using var stream = GetStream(assembly, filename);
diff --git a/src/Ryujinx.Common/Utilities/StreamUtils.cs b/src/Ryujinx.Common/Utilities/StreamUtils.cs
index 7a20c98e..74b6af5e 100644
--- a/src/Ryujinx.Common/Utilities/StreamUtils.cs
+++ b/src/Ryujinx.Common/Utilities/StreamUtils.cs
@@ -1,4 +1,6 @@
+using Microsoft.IO;
 using Ryujinx.Common.Memory;
+using System.Buffers;
 using System.IO;
 using System.Threading;
 using System.Threading.Tasks;
@@ -9,12 +11,50 @@ namespace Ryujinx.Common.Utilities
     {
         public static byte[] StreamToBytes(Stream input)
         {
-            using MemoryStream stream = MemoryStreamManager.Shared.GetStream();
+            using RecyclableMemoryStream output = StreamToRecyclableMemoryStream(input);
 
+            return output.ToArray();
+        }
 
-            input.CopyTo(stream);
+        public static IMemoryOwner<byte> StreamToRentedMemory(Stream input)
+        {
+            if (input is MemoryStream inputMemoryStream)
+            {
+                return MemoryStreamToRentedMemory(inputMemoryStream);
+            }
+            else if (input.CanSeek)
+            {
+                long bytesExpected = input.Length;
 
-            return stream.ToArray();
+                IMemoryOwner<byte> ownedMemory = ByteMemoryPool.Rent(bytesExpected);
+
+                var destSpan = ownedMemory.Memory.Span;
+
+                int totalBytesRead = 0;
+
+                while (totalBytesRead < bytesExpected)
+                {
+                    int bytesRead = input.Read(destSpan[totalBytesRead..]);
+
+                    if (bytesRead == 0)
+                    {
+                        ownedMemory.Dispose();
+
+                        throw new IOException($"Tried reading {bytesExpected} but the stream closed after reading {totalBytesRead}.");
+                    }
+
+                    totalBytesRead += bytesRead;
+                }
+
+                return ownedMemory;
+            }
+            else
+            {
+                // If input is (non-seekable) then copy twice: first into a RecyclableMemoryStream, then to a rented IMemoryOwner<byte>.
+                using RecyclableMemoryStream output = StreamToRecyclableMemoryStream(input);
+
+                return MemoryStreamToRentedMemory(output);
+            }
         }
 
         public static async Task<byte[]> StreamToBytesAsync(Stream input, CancellationToken cancellationToken = default)
@@ -25,5 +65,26 @@ namespace Ryujinx.Common.Utilities
 
             return stream.ToArray();
         }
+
+        private static IMemoryOwner<byte> MemoryStreamToRentedMemory(MemoryStream input)
+        {
+            input.Position = 0;
+
+            IMemoryOwner<byte> ownedMemory = ByteMemoryPool.Rent(input.Length);
+
+            // Discard the return value because we assume reading a MemoryStream always succeeds completely.
+            _ = input.Read(ownedMemory.Memory.Span);
+
+            return ownedMemory;
+        }
+
+        private static RecyclableMemoryStream StreamToRecyclableMemoryStream(Stream input)
+        {
+            RecyclableMemoryStream stream = MemoryStreamManager.Shared.GetStream();
+
+            input.CopyTo(stream);
+
+            return stream;
+        }
     }
 }