Fix non-seekable stream reading.

src/ImageSharp/IO/ChunkedMemoryStream.cs

@@ -0,0 +1,544 @@
+// Copyright (c) Six Labors.
+// Licensed under the Apache License, Version 2.0.
+
+using System;
+using System.IO;
+using System.Runtime.CompilerServices;
+using SixLabors.ImageSharp.Memory;
+
+namespace SixLabors.ImageSharp.IO
+{
+    /// <summary>
+    /// Provides an in-memory stream composed of non-contiguous chunks that doesn't need to be resized.
+    /// Chunks are allocated by the <see cref="MemoryAllocator"/> assigned via the constructor
+    /// and is designed to take advantage of buffer pooling when available.
+    /// </summary>
+    internal sealed class ChunkedMemoryStream : Stream
+    {
+        /// <summary>
+        /// The default length in bytes of each buffer chunk.
+        /// </summary>
+        public const int DefaultBufferLength = 4096;
+
+        // The memory allocator.
+        private readonly MemoryAllocator allocator;
+
+        // Data
+        private MemoryChunk memoryChunk;
+
+        // The length of each buffer chunk
+        private readonly int chunkLength;
+
+        // Has the stream been disposed.
+        private bool isDisposed;
+
+        // Current chunk to write to
+        private MemoryChunk writeChunk;
+
+        // Offset into chunk to write to
+        private int writeOffset;
+
+        // Current chunk to read from
+        private MemoryChunk readChunk;
+
+        // Offset into chunk to read from
+        private int readOffset;
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="ChunkedMemoryStream"/> class.
+        /// </summary>
+        public ChunkedMemoryStream(MemoryAllocator allocator)
+            : this(DefaultBufferLength, allocator)
+        {
+        }
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="ChunkedMemoryStream"/> class.
+        /// </summary>
+        /// <param name="bufferLength">The length, in bytes of each buffer chunk.</param>
+        /// <param name="allocator">The memory allocator.</param>
+        public ChunkedMemoryStream(int bufferLength, MemoryAllocator allocator)
+        {
+            Guard.MustBeGreaterThan(bufferLength, 0, nameof(bufferLength));
+            Guard.NotNull(allocator, nameof(allocator));
+
+            this.chunkLength = bufferLength;
+            this.allocator = allocator;
+        }
+
+        /// <inheritdoc/>
+        public override bool CanRead => !this.isDisposed;
+
+        /// <inheritdoc/>
+        public override bool CanSeek => !this.isDisposed;
+
+        /// <inheritdoc/>
+        public override bool CanWrite => !this.isDisposed;
+
+        /// <inheritdoc/>
+        public override long Length
+        {
+            get
+            {
+                this.EnsureNotDisposed();
+
+                int length = 0;
+                MemoryChunk chunk = this.memoryChunk;
+                while (chunk != null)
+                {
+                    MemoryChunk next = chunk.Next;
+                    if (next != null)
+                    {
+                        length += chunk.Length;
+                    }
+                    else
+                    {
+                        length += this.writeOffset;
+                    }
+
+                    chunk = next;
+                }
+
+                return length;
+            }
+        }
+
+        /// <inheritdoc/>
+        public override long Position
+        {
+            get
+            {
+                this.EnsureNotDisposed();
+
+                if (this.readChunk is null)
+                {
+                    return 0;
+                }
+
+                int pos = 0;
+                MemoryChunk chunk = this.memoryChunk;
+                while (chunk != this.readChunk)
+                {
+                    pos += chunk.Length;
+                    chunk = chunk.Next;
+                }
+
+                pos += this.readOffset;
+
+                return pos;
+            }
+
+            set
+            {
+                this.EnsureNotDisposed();
+
+                if (value < 0)
+                {
+                    throw new ArgumentOutOfRangeException(nameof(value));
+                }
+
+                // Back up current position in case new position is out of range
+                MemoryChunk backupReadChunk = this.readChunk;
+                int backupReadOffset = this.readOffset;
+
+                this.readChunk = null;
+                this.readOffset = 0;
+
+                int leftUntilAtPos = (int)value;
+                MemoryChunk chunk = this.memoryChunk;
+                while (chunk != null)
+                {
+                    if ((leftUntilAtPos < chunk.Length)
+                            || ((leftUntilAtPos == chunk.Length)
+                            && (chunk.Next is null)))
+                    {
+                        // The desired position is in this chunk
+                        this.readChunk = chunk;
+                        this.readOffset = leftUntilAtPos;
+                        break;
+                    }
+
+                    leftUntilAtPos -= chunk.Length;
+                    chunk = chunk.Next;
+                }
+
+                if (this.readChunk is null)
+                {
+                    // Position is out of range
+                    this.readChunk = backupReadChunk;
+                    this.readOffset = backupReadOffset;
+                    throw new ArgumentOutOfRangeException(nameof(value));
+                }
+            }
+        }
+
+        /// <inheritdoc/>
+        public override long Seek(long offset, SeekOrigin origin)
+        {
+            this.EnsureNotDisposed();
+
+            switch (origin)
+            {
+                case SeekOrigin.Begin:
+                    this.Position = offset;
+                    break;
+
+                case SeekOrigin.Current:
+                    this.Position += offset;
+                    break;
+
+                case SeekOrigin.End:
+                    this.Position = this.Length + offset;
+                    break;
+            }
+
+            return this.Position;
+        }
+
+        /// <inheritdoc/>
+        public override void SetLength(long value)
+            => throw new NotSupportedException();
+
+        /// <inheritdoc/>
+        protected override void Dispose(bool disposing)
+        {
+            if (this.isDisposed)
+            {
+                return;
+            }
+
+            try
+            {
+                this.isDisposed = true;
+                if (disposing)
+                {
+                    this.ReleaseMemoryChunks(this.memoryChunk);
+                }
+
+                this.memoryChunk = null;
+                this.writeChunk = null;
+                this.readChunk = null;
+            }
+            finally
+            {
+                base.Dispose(disposing);
+            }
+        }
+
+        /// <inheritdoc/>
+        public override void Flush()
+        {
+        }
+
+        /// <inheritdoc/>
+        public override int Read(byte[] buffer, int offset, int count)
+        {
+            Guard.NotNull(buffer, nameof(buffer));
+            Guard.MustBeGreaterThanOrEqualTo(offset, 0, nameof(offset));
+            Guard.MustBeGreaterThanOrEqualTo(count, 0, nameof(count));
+            if (buffer.Length - offset < count)
+            {
+                throw new ArgumentException($"{offset} subtracted from the buffer length is less than {count}");
+            }
+
+            this.EnsureNotDisposed();
+
+            if (this.readChunk is null)
+            {
+                if (this.memoryChunk is null)
+                {
+                    return 0;
+                }
+
+                this.readChunk = this.memoryChunk;
+                this.readOffset = 0;
+            }
+
+            byte[] chunkBuffer = this.writeChunk.Buffer.Array;
+            int chunkSize = this.readChunk.Length;
+            if (this.readChunk.Next is null)
+            {
+                chunkSize = this.writeOffset;
+            }
+
+            int bytesRead = 0;
+
+            while (count > 0)
+            {
+                if (this.readOffset == chunkSize)
+                {
+                    // Exit if no more chunks are currently available
+                    if (this.readChunk.Next is null)
+                    {
+                        break;
+                    }
+
+                    this.readChunk = this.readChunk.Next;
+                    this.readOffset = 0;
+                    chunkBuffer = this.writeChunk.Buffer.Array;
+                    chunkSize = this.readChunk.Length;
+                    if (this.readChunk.Next is null)
+                    {
+                        chunkSize = this.writeOffset;
+                    }
+                }
+
+                int readCount = Math.Min(count, chunkSize - this.readOffset);
+                Buffer.BlockCopy(chunkBuffer, this.readOffset, buffer, offset, readCount);
+                offset += readCount;
+                count -= readCount;
+                this.readOffset += readCount;
+                bytesRead += readCount;
+            }
+
+            return bytesRead;
+        }
+
+        /// <inheritdoc/>
+        public override int ReadByte()
+        {
+            this.EnsureNotDisposed();
+
+            if (this.readChunk is null)
+            {
+                if (this.memoryChunk is null)
+                {
+                    return 0;
+                }
+
+                this.readChunk = this.memoryChunk;
+                this.readOffset = 0;
+            }
+
+            byte[] chunkBuffer = this.writeChunk.Buffer.Array;
+            int chunkSize = this.readChunk.Length;
+            if (this.readChunk.Next is null)
+            {
+                chunkSize = this.writeOffset;
+            }
+
+            if (this.readOffset == chunkSize)
+            {
+                // Exit if no more chunks are currently available
+                if (this.readChunk.Next is null)
+                {
+                    return -1;
+                }
+
+                this.readChunk = this.readChunk.Next;
+                this.readOffset = 0;
+                chunkBuffer = this.writeChunk.Buffer.Array;
+            }
+
+            return chunkBuffer[this.readOffset++];
+        }
+
+        /// <inheritdoc/>
+        public override void Write(byte[] buffer, int offset, int count)
+        {
+            this.EnsureNotDisposed();
+
+            if (this.memoryChunk is null)
+            {
+                this.memoryChunk = this.AllocateMemoryChunk();
+                this.writeChunk = this.memoryChunk;
+                this.writeOffset = 0;
+            }
+
+            byte[] chunkBuffer = this.writeChunk.Buffer.Array;
+            int chunkSize = this.writeChunk.Length;
+
+            while (count > 0)
+            {
+                if (this.writeOffset == chunkSize)
+                {
+                    // Allocate a new chunk if the current one is full
+                    this.writeChunk.Next = this.AllocateMemoryChunk();
+                    this.writeChunk = this.writeChunk.Next;
+                    this.writeOffset = 0;
+                    chunkBuffer = this.writeChunk.Buffer.Array;
+                    chunkSize = this.writeChunk.Length;
+                }
+
+                int copyCount = Math.Min(count, chunkSize - this.writeOffset);
+                Buffer.BlockCopy(buffer, offset, chunkBuffer, this.writeOffset, copyCount);
+                offset += copyCount;
+                count -= copyCount;
+                this.writeOffset += copyCount;
+            }
+        }
+
+        /// <inheritdoc/>
+        public override void WriteByte(byte value)
+        {
+            this.EnsureNotDisposed();
+
+            if (this.memoryChunk is null)
+            {
+                this.memoryChunk = this.AllocateMemoryChunk();
+                this.writeChunk = this.memoryChunk;
+                this.writeOffset = 0;
+            }
+
+            byte[] chunkBuffer = this.writeChunk.Buffer.Array;
+            int chunkSize = this.writeChunk.Length;
+
+            if (this.writeOffset == chunkSize)
+            {
+                // Allocate a new chunk if the current one is full
+                this.writeChunk.Next = this.AllocateMemoryChunk();
+                this.writeChunk = this.writeChunk.Next;
+                this.writeOffset = 0;
+                chunkBuffer = this.writeChunk.Buffer.Array;
+            }
+
+            chunkBuffer[this.writeOffset++] = value;
+        }
+
+        /// <summary>
+        /// Copy entire buffer into an array.
+        /// </summary>
+        /// <returns>The <see cref="T:byte[]"/>.</returns>
+        public byte[] ToArray()
+        {
+            int length = (int)this.Length; // This will throw if stream is closed
+            byte[] copy = new byte[this.Length];
+
+            MemoryChunk backupReadChunk = this.readChunk;
+            int backupReadOffset = this.readOffset;
+
+            this.readChunk = this.memoryChunk;
+            this.readOffset = 0;
+            this.Read(copy, 0, length);
+
+            this.readChunk = backupReadChunk;
+            this.readOffset = backupReadOffset;
+
+            return copy;
+        }
+
+        /// <summary>
+        /// Write remainder of this stream to another stream.
+        /// </summary>
+        /// <param name="stream">The stream to write to.</param>
+        public void WriteTo(Stream stream)
+        {
+            this.EnsureNotDisposed();
+
+            Guard.NotNull(stream, nameof(stream));
+
+            if (this.readChunk is null)
+            {
+                if (this.memoryChunk is null)
+                {
+                    return;
+                }
+
+                this.readChunk = this.memoryChunk;
+                this.readOffset = 0;
+            }
+
+            byte[] chunkBuffer = this.readChunk.Buffer.Array;
+            int chunkSize = this.readChunk.Length;
+            if (this.readChunk.Next is null)
+            {
+                chunkSize = this.writeOffset;
+            }
+
+            // Following code mirrors Read() logic (readChunk/readOffset should
+            // point just past last byte of last chunk when done)
+            // loop until end of chunks is found
+            while (true)
+            {
+                if (this.readOffset == chunkSize)
+                {
+                    // Exit if no more chunks are currently available
+                    if (this.readChunk.Next is null)
+                    {
+                        break;
+                    }
+
+                    this.readChunk = this.readChunk.Next;
+                    this.readOffset = 0;
+                    chunkBuffer = this.readChunk.Buffer.Array;
+                    chunkSize = this.readChunk.Length;
+                    if (this.readChunk.Next is null)
+                    {
+                        chunkSize = this.writeOffset;
+                    }
+                }
+
+                int writeCount = chunkSize - this.readOffset;
+                stream.Write(chunkBuffer, this.readOffset, writeCount);
+                this.readOffset = chunkSize;
+            }
+        }
+
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        private void EnsureNotDisposed()
+        {
+            if (this.isDisposed)
+            {
+                ThrowDisposed();
+            }
+        }
+
+        [MethodImpl(MethodImplOptions.NoInlining)]
+        private static void ThrowDisposed()
+        {
+            throw new ObjectDisposedException(null, "The stream is closed.");
+        }
+
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        private MemoryChunk AllocateMemoryChunk()
+        {
+            IManagedByteBuffer buffer = this.allocator.AllocateManagedByteBuffer(this.chunkLength);
+            return new MemoryChunk
+            {
+                Buffer = buffer,
+                Next = null,
+                Length = this.chunkLength
+            };
+        }
+
+        private void ReleaseMemoryChunks(MemoryChunk chunk)
+        {
+            while (chunk != null)
+            {
+                chunk.Dispose();
+                chunk = chunk.Next;
+            }
+        }
+
+        private sealed class MemoryChunk : IDisposable
+        {
+            private bool isDisposed;
+
+            public IManagedByteBuffer Buffer { get; set; }
+
+            public MemoryChunk Next { get; set; }
+
+            public int Length { get; set; }
+
+            private void Dispose(bool disposing)
+            {
+                if (!this.isDisposed)
+                {
+                    if (disposing)
+                    {
+                        this.Buffer.Dispose();
+                    }
+
+                    this.Buffer = null;
+                    this.isDisposed = true;
+                }
+            }
+
+            public void Dispose()
+            {
+                this.Dispose(disposing: true);
+                GC.SuppressFinalize(this);
+            }
+        }
+    }
+}

src/ImageSharp/Image.FromStream.cs

@@ -8,6 +8,7 @@ using System.Text;
 using System.Threading;
 using System.Threading.Tasks;
 using SixLabors.ImageSharp.Formats;
+using SixLabors.ImageSharp.IO;
 using SixLabors.ImageSharp.Memory;
 using SixLabors.ImageSharp.PixelFormats;
 
@@ -731,7 +732,7 @@ namespace SixLabors.ImageSharp
             }
 
             // We want to be able to load images from things like HttpContext.Request.Body
-            using MemoryStream memoryStream = configuration.MemoryAllocator.AllocateFixedCapacityMemoryStream(stream.Length);
+            using var memoryStream = new ChunkedMemoryStream(configuration.MemoryAllocator);
             stream.CopyTo(memoryStream, configuration.StreamProcessingBufferSize);
             memoryStream.Position = 0;
 
@@ -775,7 +776,7 @@ namespace SixLabors.ImageSharp
                 return await action(stream, cancellationToken).ConfigureAwait(false);
             }
 
-            using MemoryStream memoryStream = configuration.MemoryAllocator.AllocateFixedCapacityMemoryStream(stream.Length);
+            using var memoryStream = new ChunkedMemoryStream(configuration.MemoryAllocator);
             await stream.CopyToAsync(memoryStream, configuration.StreamProcessingBufferSize, cancellationToken).ConfigureAwait(false);
             memoryStream.Position = 0;
 

tests/ImageSharp.Tests/IO/ChunkedMemoryStreamTests.cs

@@ -0,0 +1,183 @@
+// Copyright (c) Six Labors.
+// Licensed under the Apache License, Version 2.0.
+
+using System;
+using System.Collections.Generic;
+using System.IO;
+using SixLabors.ImageSharp.IO;
+using SixLabors.ImageSharp.Memory;
+using Xunit;
+
+namespace SixLabors.ImageSharp.Tests.IO
+{
+    /// <summary>
+    /// Tests for the <see cref="ChunkedMemoryStream"/> class.
+    /// </summary>
+    public class ChunkedMemoryStreamTests
+    {
+        private readonly MemoryAllocator allocator;
+
+        public ChunkedMemoryStreamTests()
+        {
+            this.allocator = Configuration.Default.MemoryAllocator;
+        }
+
+        [Fact]
+        public void MemoryStream_Ctor_InvalidCapacities()
+        {
+            Assert.Throws<ArgumentOutOfRangeException>(() => new ChunkedMemoryStream(int.MinValue, this.allocator));
+            Assert.Throws<ArgumentOutOfRangeException>(() => new ChunkedMemoryStream(0, this.allocator));
+        }
+
+        [Fact]
+        public void ChunkedPooledMemoryStream_GetPositionTest_Negative()
+        {
+            using var ms = new ChunkedMemoryStream(this.allocator);
+            long iCurrentPos = ms.Position;
+            for (int i = -1; i > -6; i--)
+            {
+                Assert.Throws<ArgumentOutOfRangeException>(() => ms.Position = i);
+                Assert.Equal(ms.Position, iCurrentPos);
+            }
+        }
+
+        [Fact]
+        public void MemoryStream_ReadTest_Negative()
+        {
+            var ms2 = new ChunkedMemoryStream(this.allocator);
+
+            Assert.Throws<ArgumentNullException>(() => ms2.Read(null, 0, 0));
+            Assert.Throws<ArgumentOutOfRangeException>(() => ms2.Read(new byte[] { 1 }, -1, 0));
+            Assert.Throws<ArgumentOutOfRangeException>(() => ms2.Read(new byte[] { 1 }, 0, -1));
+            Assert.Throws<ArgumentException>(null, () => ms2.Read(new byte[] { 1 }, 2, 0));
+            Assert.Throws<ArgumentException>(null, () => ms2.Read(new byte[] { 1 }, 0, 2));
+
+            ms2.Dispose();
+
+            Assert.Throws<ObjectDisposedException>(() => ms2.Read(new byte[] { 1 }, 0, 1));
+        }
+
+        [Fact]
+        public void MemoryStream_WriteToTests()
+        {
+            using (var ms2 = new ChunkedMemoryStream(this.allocator))
+            {
+                byte[] bytArrRet;
+                byte[] bytArr = new byte[] { byte.MinValue, byte.MaxValue, 1, 2, 3, 4, 5, 6, 128, 250 };
+
+                // [] Write to FileStream, check the filestream
+                ms2.Write(bytArr, 0, bytArr.Length);
+
+                using var readonlyStream = new ChunkedMemoryStream(this.allocator);
+                ms2.WriteTo(readonlyStream);
+                readonlyStream.Flush();
+                readonlyStream.Position = 0;
+                bytArrRet = new byte[(int)readonlyStream.Length];
+                readonlyStream.Read(bytArrRet, 0, (int)readonlyStream.Length);
+                for (int i = 0; i < bytArr.Length; i++)
+                {
+                    Assert.Equal(bytArr[i], bytArrRet[i]);
+                }
+            }
+
+            // [] Write to memoryStream, check the memoryStream
+            using (var ms2 = new ChunkedMemoryStream(this.allocator))
+            using (var ms3 = new ChunkedMemoryStream(this.allocator))
+            {
+                byte[] bytArrRet;
+                byte[] bytArr = new byte[] { byte.MinValue, byte.MaxValue, 1, 2, 3, 4, 5, 6, 128, 250 };
+
+                ms2.Write(bytArr, 0, bytArr.Length);
+                ms2.WriteTo(ms3);
+                ms3.Position = 0;
+                bytArrRet = new byte[(int)ms3.Length];
+                ms3.Read(bytArrRet, 0, (int)ms3.Length);
+                for (int i = 0; i < bytArr.Length; i++)
+                {
+                    Assert.Equal(bytArr[i], bytArrRet[i]);
+                }
+            }
+        }
+
+        [Fact]
+        public void MemoryStream_WriteToTests_Negative()
+        {
+            using var ms2 = new ChunkedMemoryStream(this.allocator);
+            Assert.Throws<ArgumentNullException>(() => ms2.WriteTo(null));
+
+            ms2.Write(new byte[] { 1 }, 0, 1);
+            var readonlyStream = new MemoryStream(new byte[1028], false);
+            Assert.Throws<NotSupportedException>(() => ms2.WriteTo(readonlyStream));
+
+            readonlyStream.Dispose();
+
+            // [] Pass in a closed stream
+            Assert.Throws<ObjectDisposedException>(() => ms2.WriteTo(readonlyStream));
+        }
+
+        [Fact]
+        public void MemoryStream_CopyTo_Invalid()
+        {
+            ChunkedMemoryStream memoryStream;
+            const string BufferSize = "bufferSize";
+            using (memoryStream = new ChunkedMemoryStream(this.allocator))
+            {
+                const string Destination = "destination";
+                Assert.Throws<ArgumentNullException>(Destination, () => memoryStream.CopyTo(destination: null));
+
+                // Validate the destination parameter first.
+                Assert.Throws<ArgumentNullException>(Destination, () => memoryStream.CopyTo(destination: null, bufferSize: 0));
+                Assert.Throws<ArgumentNullException>(Destination, () => memoryStream.CopyTo(destination: null, bufferSize: -1));
+
+                // Then bufferSize.
+                Assert.Throws<ArgumentOutOfRangeException>(BufferSize, () => memoryStream.CopyTo(Stream.Null, bufferSize: 0)); // 0-length buffer doesn't make sense.
+                Assert.Throws<ArgumentOutOfRangeException>(BufferSize, () => memoryStream.CopyTo(Stream.Null, bufferSize: -1));
+            }
+
+            // After the Stream is disposed, we should fail on all CopyTos.
+            Assert.Throws<ArgumentOutOfRangeException>(BufferSize, () => memoryStream.CopyTo(Stream.Null, bufferSize: 0)); // Not before bufferSize is validated.
+            Assert.Throws<ArgumentOutOfRangeException>(BufferSize, () => memoryStream.CopyTo(Stream.Null, bufferSize: -1));
+
+            ChunkedMemoryStream disposedStream = memoryStream;
+
+            // We should throw first for the source being disposed...
+            Assert.Throws<ObjectDisposedException>(() => memoryStream.CopyTo(disposedStream, 1));
+
+            // Then for the destination being disposed.
+            memoryStream = new ChunkedMemoryStream(this.allocator);
+            Assert.Throws<ObjectDisposedException>(() => memoryStream.CopyTo(disposedStream, 1));
+            memoryStream.Dispose();
+        }
+
+        [Theory]
+        [MemberData(nameof(CopyToData))]
+        public void CopyTo(Stream source, byte[] expected)
+        {
+            using var destination = new ChunkedMemoryStream(this.allocator);
+            source.CopyTo(destination);
+            Assert.InRange(source.Position, source.Length, int.MaxValue); // Copying the data should have read to the end of the stream or stayed past the end.
+            Assert.Equal(expected, destination.ToArray());
+        }
+
+        public static IEnumerable<object[]> CopyToData()
+        {
+            // Stream is positioned @ beginning of data
+            byte[] data1 = new byte[] { 1, 2, 3 };
+            var stream1 = new MemoryStream(data1);
+
+            yield return new object[] { stream1, data1 };
+
+            // Stream is positioned in the middle of data
+            byte[] data2 = new byte[] { 0xff, 0xf3, 0xf0 };
+            var stream2 = new MemoryStream(data2) { Position = 1 };
+
+            yield return new object[] { stream2, new byte[] { 0xf3, 0xf0 } };
+
+            // Stream is positioned after end of data
+            byte[] data3 = data2;
+            var stream3 = new MemoryStream(data3) { Position = data3.Length + 1 };
+
+            yield return new object[] { stream3, Array.Empty<byte>() };
+        }
+    }
+}

tests/ImageSharp.Tests/Image/ImageTests.Load_FromStream_PassLocalConfiguration.cs

@@ -2,7 +2,7 @@
 // Licensed under the Apache License, Version 2.0.
 
 using System.IO;
-
+using System.Threading.Tasks;
 using SixLabors.ImageSharp.Formats;
 using SixLabors.ImageSharp.PixelFormats;
 
@@ -39,7 +39,7 @@ namespace SixLabors.ImageSharp.Tests
             [Fact]
             public void NonSeekableStream()
             {
-                var stream = new NoneSeekableStream(this.DataStream);
+                var stream = new NonSeekableStream(this.DataStream);
                 var img = Image.Load<Rgba32>(this.TopLevelConfiguration, stream);
 
                 Assert.NotNull(img);
@@ -47,6 +47,17 @@ namespace SixLabors.ImageSharp.Tests
                 this.TestFormat.VerifySpecificDecodeCall<Rgba32>(this.Marker, this.TopLevelConfiguration);
             }
 
+            [Fact]
+            public async Task NonSeekableStreamAsync()
+            {
+                var stream = new NonSeekableStream(this.DataStream);
+                Image<Rgba32> img = await Image.LoadAsync<Rgba32>(this.TopLevelConfiguration, stream);
+
+                Assert.NotNull(img);
+
+                this.TestFormat.VerifySpecificDecodeCall<Rgba32>(this.Marker, this.TopLevelConfiguration);
+            }
+
             [Fact]
             public void Configuration_Stream_Decoder_Specific()
             {

tests/ImageSharp.Tests/Image/NonSeekableStream.cs

@@ -0,0 +1,43 @@
+// Copyright (c) Six Labors.
+// Licensed under the Apache License, Version 2.0.
+
+using System;
+using System.IO;
+
+namespace SixLabors.ImageSharp.Tests
+{
+    internal class NonSeekableStream : Stream
+    {
+        private readonly Stream dataStream;
+
+        public NonSeekableStream(Stream dataStream)
+            => this.dataStream = dataStream;
+
+        public override bool CanRead => this.dataStream.CanRead;
+
+        public override bool CanSeek => false;
+
+        public override bool CanWrite => false;
+
+        public override long Length => throw new NotSupportedException();
+
+        public override long Position
+        {
+            get { throw new NotSupportedException(); }
+            set { throw new NotSupportedException(); }
+        }
+
+        public override void Flush() => this.dataStream.Flush();
+
+        public override int Read(byte[] buffer, int offset, int count) => this.dataStream.Read(buffer, offset, count);
+
+        public override long Seek(long offset, SeekOrigin origin)
+            => throw new NotSupportedException();
+
+        public override void SetLength(long value)
+            => throw new NotSupportedException();
+
+        public override void Write(byte[] buffer, int offset, int count)
+            => throw new NotImplementedException();
+    }
+}

tests/ImageSharp.Tests/Image/NoneSeekableStream.cs

@@ -1,53 +0,0 @@
-// Copyright (c) Six Labors.
-// Licensed under the Apache License, Version 2.0.
-
-using System;
-using System.IO;
-
-namespace SixLabors.ImageSharp.Tests
-{
-    internal class NoneSeekableStream : Stream
-    {
-        private Stream dataStream;
-
-        public NoneSeekableStream(Stream dataStream)
-        {
-            this.dataStream = dataStream;
-        }
-
-        public override bool CanRead => this.dataStream.CanRead;
-
-        public override bool CanSeek => false;
-
-        public override bool CanWrite => false;
-
-        public override long Length => this.dataStream.Length;
-
-        public override long Position { get => this.dataStream.Position; set => throw new NotImplementedException(); }
-
-        public override void Flush()
-        {
-            this.dataStream.Flush();
-        }
-
-        public override int Read(byte[] buffer, int offset, int count)
-        {
-            return this.dataStream.Read(buffer, offset, count);
-        }
-
-        public override long Seek(long offset, SeekOrigin origin)
-        {
-            throw new NotImplementedException();
-        }
-
-        public override void SetLength(long value)
-        {
-            throw new NotImplementedException();
-        }
-
-        public override void Write(byte[] buffer, int offset, int count)
-        {
-            throw new NotImplementedException();
-        }
-    }
-}