Merge branch 'main' into stefannikolei/nullable/exifprofile

src/ImageSharp/Compression/Zlib/DeflateThrowHelper.cs

@@ -1,23 +1,33 @@
 // Copyright (c) Six Labors.
 // Licensed under the Six Labors Split License.
 
+using System.Diagnostics.CodeAnalysis;
+
 namespace SixLabors.ImageSharp.Compression.Zlib;
 
 internal static class DeflateThrowHelper
 {
+    [DoesNotReturn]
     public static void ThrowAlreadyFinished() => throw new InvalidOperationException("Finish() already called.");
 
+    [DoesNotReturn]
     public static void ThrowAlreadyClosed() => throw new InvalidOperationException("Deflator already closed.");
 
+    [DoesNotReturn]
     public static void ThrowUnknownCompression() => throw new InvalidOperationException("Unknown compression function.");
 
+    [DoesNotReturn]
     public static void ThrowNotProcessed() => throw new InvalidOperationException("Old input was not completely processed.");
 
+    [DoesNotReturn]
     public static void ThrowNull(string name) => throw new ArgumentNullException(name);
 
+    [DoesNotReturn]
     public static void ThrowOutOfRange(string name) => throw new ArgumentOutOfRangeException(name);
 
+    [DoesNotReturn]
     public static void ThrowHeapViolated() => throw new InvalidOperationException("Huffman heap invariant violated.");
 
+    [DoesNotReturn]
     public static void ThrowNoDeflate() => throw new ImageFormatException("Cannot deflate all input.");
 }

src/ImageSharp/Compression/Zlib/Deflater.cs

@@ -1,6 +1,5 @@
 // Copyright (c) Six Labors.
 // Licensed under the Six Labors Split License.
-#nullable disable
 
 using System.Runtime.CompilerServices;
 using SixLabors.ImageSharp.Memory;
@@ -285,7 +284,6 @@ internal sealed class Deflater : IDisposable
         if (!this.isDisposed)
         {
             this.engine.Dispose();
-            this.engine = null;
             this.isDisposed = true;
         }
     }

src/ImageSharp/Compression/Zlib/DeflaterEngine.cs

@@ -1,6 +1,5 @@
 // Copyright (c) Six Labors.
 // Licensed under the Six Labors Split License.
-#nullable disable
 
 using System.Buffers;
 using System.Runtime.CompilerServices;
@@ -87,7 +86,7 @@ internal sealed unsafe class DeflaterEngine : IDisposable
     /// <summary>
     /// The input data for compression.
     /// </summary>
-    private byte[] inputBuf;
+    private byte[]? inputBuf;
 
     /// <summary>
     /// The offset into inputBuf, where input data starts.
@@ -222,7 +221,7 @@ internal sealed unsafe class DeflaterEngine : IDisposable
     /// <param name="buffer">The buffer containing input data.</param>
     /// <param name="offset">The offset of the first byte of data.</param>
     /// <param name="count">The number of bytes of data to use as input.</param>
-    public void SetInput(byte[] buffer, int offset, int count)
+    public void SetInput(byte[]? buffer, int offset, int count)
     {
         if (buffer is null)
         {
@@ -362,6 +361,8 @@ internal sealed unsafe class DeflaterEngine : IDisposable
                 more = this.inputEnd - this.inputOff;
             }
 
+            ArgumentNullException.ThrowIfNull(this.inputBuf);
+
             Unsafe.CopyBlockUnaligned(
                 ref this.window.Span[this.strstart + this.lookahead],
                 ref this.inputBuf[this.inputOff],
@@ -393,11 +394,6 @@ internal sealed unsafe class DeflaterEngine : IDisposable
             this.prevMemoryHandle.Dispose();
             this.prevMemoryOwner.Dispose();
 
-            this.windowMemoryOwner = null;
-            this.headMemoryOwner = null;
-            this.prevMemoryOwner = null;
-            this.huffman = null;
-
             this.isDisposed = true;
         }
     }

src/ImageSharp/Compression/Zlib/DeflaterHuffman.cs

@@ -1,6 +1,5 @@
 // Copyright (c) Six Labors.
 // Licensed under the Six Labors Split License.
-#nullable disable
 
 using System.Buffers;
 using System.Runtime.CompilerServices;
@@ -427,10 +426,6 @@ internal sealed unsafe class DeflaterHuffman : IDisposable
             this.blTree.Dispose();
             this.distTree.Dispose();
 
-            this.Pending = null;
-            this.literalTree = null;
-            this.blTree = null;
-            this.distTree = null;
             this.isDisposed = true;
         }
     }
@@ -977,10 +972,6 @@ internal sealed unsafe class DeflaterHuffman : IDisposable
                 this.codesMemoryHandle.Dispose();
                 this.codesMemoryOwner.Dispose();
 
-                this.frequenciesMemoryOwner = null;
-                this.lengthsMemoryOwner = null;
-                this.codesMemoryOwner = null;
-
                 this.isDisposed = true;
             }
         }

src/ImageSharp/Compression/Zlib/DeflaterOutputStream.cs

@@ -1,6 +1,5 @@
 // Copyright (c) Six Labors.
 // Licensed under the Six Labors Split License.
-#nullable disable
 
 using System.Buffers;
 using SixLabors.ImageSharp.Memory;
@@ -137,8 +136,6 @@ internal sealed class DeflaterOutputStream : Stream
                 this.memoryOwner.Dispose();
             }
 
-            this.deflater = null;
-            this.memoryOwner = null;
             this.isDisposed = true;
             base.Dispose(disposing);
         }

src/ImageSharp/Compression/Zlib/DeflaterPendingBuffer.cs

@@ -1,6 +1,5 @@
 // Copyright (c) Six Labors.
 // Licensed under the Six Labors Split License.
-#nullable disable
 
 using System.Buffers;
 using System.Runtime.CompilerServices;
@@ -180,7 +179,6 @@ internal sealed unsafe class DeflaterPendingBuffer : IDisposable
         {
             this.bufferMemoryHandle.Dispose();
             this.bufferMemoryOwner.Dispose();
-            this.bufferMemoryOwner = null;
             this.isDisposed = true;
         }
     }

src/ImageSharp/Compression/Zlib/ZlibDeflateStream.cs

@@ -1,6 +1,5 @@
 // Copyright (c) Six Labors.
 // Licensed under the Six Labors Split License.
-#nullable disable
 
 using System.Runtime.CompilerServices;
 using SixLabors.ImageSharp.Formats.Png;
@@ -172,8 +171,6 @@ internal sealed class ZlibDeflateStream : Stream
             this.rawStream.WriteByte((byte)(crc & 0xFF));
         }
 
-        this.deflateStream = null;
-
         base.Dispose(disposing);
         this.isDisposed = true;
     }

src/ImageSharp/Compression/Zlib/ZlibInflateStream.cs

@@ -1,7 +1,7 @@
 // Copyright (c) Six Labors.
 // Licensed under the Six Labors Split License.
-#nullable disable
 
+using System.Diagnostics.CodeAnalysis;
 using System.IO.Compression;
 using SixLabors.ImageSharp.IO;
 
@@ -90,7 +90,7 @@ internal sealed class ZlibInflateStream : Stream
     /// <summary>
     /// Gets the compressed stream over the deframed inner stream.
     /// </summary>
-    public DeflateStream CompressedStream { get; private set; }
+    public DeflateStream? CompressedStream { get; private set; }
 
     /// <summary>
     /// Adds new bytes from a frame found in the original stream.
@@ -98,6 +98,7 @@ internal sealed class ZlibInflateStream : Stream
     /// <param name="bytes">The current remaining data according to the chunk length.</param>
     /// <param name="isCriticalChunk">Whether the chunk to be inflated is a critical chunk.</param>
     /// <returns>The <see cref="bool"/>.</returns>
+    [MemberNotNullWhen(true, nameof(CompressedStream))]
     public bool AllocateNewBytes(int bytes, bool isCriticalChunk)
     {
         this.currentDataRemaining = bytes;
@@ -210,6 +211,7 @@ internal sealed class ZlibInflateStream : Stream
         this.isDisposed = true;
     }
 
+    [MemberNotNullWhen(true, nameof(CompressedStream))]
     private bool InitializeInflateStream(bool isCriticalChunk)
     {
         // Read the zlib header : http://tools.ietf.org/html/rfc1950

src/ImageSharp/Diagnostics/MemoryDiagnostics.cs

@@ -1,6 +1,5 @@
 // Copyright (c) Six Labors.
 // Licensed under the Six Labors Split License.
-#nullable disable
 
 namespace SixLabors.ImageSharp.Diagnostics;
 
@@ -17,7 +16,7 @@ public static class MemoryDiagnostics
 {
     private static int totalUndisposedAllocationCount;
 
-    private static UndisposedAllocationDelegate undisposedAllocation;
+    private static UndisposedAllocationDelegate? undisposedAllocation;
     private static int undisposedAllocationSubscriptionCounter;
     private static readonly object SyncRoot = new();
 
@@ -50,12 +49,12 @@ public static class MemoryDiagnostics
     /// <summary>
     /// Fires when ImageSharp allocates memory from a MemoryAllocator
     /// </summary>
-    internal static event Action MemoryAllocated;
+    internal static event Action? MemoryAllocated;
 
     /// <summary>
     /// Fires when ImageSharp releases memory allocated from a MemoryAllocator
     /// </summary>
-    internal static event Action MemoryReleased;
+    internal static event Action? MemoryReleased;
 
     /// <summary>
     /// Gets a value indicating the total number of memory resource objects leaked to the finalizer.

src/ImageSharp/Formats/Jpeg/Components/Decoder/JFifMarker.cs

@@ -26,16 +26,6 @@ internal readonly struct JFifMarker : IEquatable<JFifMarker>
     /// <param name="yDensity">The vertical pixel density.</param>
     private JFifMarker(byte majorVersion, byte minorVersion, byte densityUnits, short xDensity, short yDensity)
     {
-        if (xDensity <= 0)
-        {
-            JpegThrowHelper.ThrowInvalidImageContentException($"X-Density {xDensity} must be greater than 0.");
-        }
-
-        if (yDensity <= 0)
-        {
-            JpegThrowHelper.ThrowInvalidImageContentException($"Y-Density {yDensity} must be greater than 0.");
-        }
-
         this.MajorVersion = majorVersion;
         this.MinorVersion = minorVersion;
 
@@ -64,12 +54,12 @@ internal readonly struct JFifMarker : IEquatable<JFifMarker>
     public PixelResolutionUnit DensityUnits { get; }
 
     /// <summary>
-    /// Gets the horizontal pixel density. Must not be zero.
+    /// Gets the horizontal pixel density.
     /// </summary>
     public short XDensity { get; }
 
     /// <summary>
-    /// Gets the vertical pixel density. Must not be zero.
+    /// Gets the vertical pixel density.
     /// </summary>
     public short YDensity { get; }
 
@@ -88,12 +78,8 @@ internal readonly struct JFifMarker : IEquatable<JFifMarker>
             byte densityUnits = bytes[7];
             short xDensity = (short)((bytes[8] << 8) | bytes[9]);
             short yDensity = (short)((bytes[10] << 8) | bytes[11]);
-
-            if (xDensity > 0 && yDensity > 0)
-            {
-                marker = new JFifMarker(majorVersion, minorVersion, densityUnits, xDensity, yDensity);
-                return true;
-            }
+            marker = new JFifMarker(majorVersion, minorVersion, densityUnits, xDensity, yDensity);
+            return true;
         }
 
         marker = default;

src/ImageSharp/Formats/Jpeg/Components/Decoder/SpectralConverter.cs

@@ -121,4 +121,10 @@ internal abstract class SpectralConverter
 
         return size;
     }
+
+    /// <summary>
+    /// Gets a value indicating whether the converter has a pixel buffer.
+    /// </summary>
+    /// <returns><see langword="true"/> if the converter has a pixel buffer; otherwise, <see langword="false"/>.</returns>
+    public abstract bool HasPixelBuffer();
 }

src/ImageSharp/Formats/Jpeg/Components/Decoder/SpectralConverter{TPixel}.cs

@@ -85,6 +85,12 @@ internal class SpectralConverter<TPixel> : SpectralConverter, IDisposable
     /// </summary>
     public Configuration Configuration { get; }
 
+    /// <summary>
+    /// Gets a value indicating whether the converter has a pixel buffer.
+    /// </summary>
+    /// <returns><see langword="true"/> if the converter has a pixel buffer; otherwise, <see langword="false"/>.</returns>
+    public override bool HasPixelBuffer() => this.pixelBuffer is not null;
+
     /// <summary>
     /// Gets converted pixel buffer.
     /// </summary>

src/ImageSharp/Formats/Jpeg/JpegDecoderCore.cs

@@ -356,6 +356,18 @@ internal sealed class JpegDecoderCore : IRawJpegData, IImageDecoderInternals
                 // to uint to avoid sign extension.
                 if (stream.RemainingBytes < (uint)markerContentByteSize)
                 {
+                    if (metadataOnly && this.Metadata != null && this.Frame != null)
+                    {
+                        // We have enough data to decode the image, so we can stop parsing.
+                        return;
+                    }
+
+                    if (this.Metadata != null && this.Frame != null && spectralConverter.HasPixelBuffer())
+                    {
+                        // We have enough data to decode the image, so we can stop parsing.
+                        return;
+                    }
+
                     JpegThrowHelper.ThrowNotEnoughBytesForMarker(fileMarker.Marker);
                 }
 

src/ImageSharp/Formats/Tiff/Compression/Decompressors/DeflateTiffCompression.cs

@@ -50,19 +50,21 @@ internal sealed class DeflateTiffCompression : TiffBaseDecompressor
                 return left > 0 ? left : 0;
             }))
         {
-            deframeStream.AllocateNewBytes(byteCount, true);
-            DeflateStream dataStream = deframeStream.CompressedStream;
-
-            int totalRead = 0;
-            while (totalRead < buffer.Length)
+            if (deframeStream.AllocateNewBytes(byteCount, true))
             {
-                int bytesRead = dataStream.Read(buffer, totalRead, buffer.Length - totalRead);
-                if (bytesRead <= 0)
+                DeflateStream? dataStream = deframeStream.CompressedStream;
+
+                int totalRead = 0;
+                while (totalRead < buffer.Length)
                 {
-                    break;
-                }
+                    int bytesRead = dataStream.Read(buffer, totalRead, buffer.Length - totalRead);
+                    if (bytesRead <= 0)
+                    {
+                        break;
+                    }
 
-                totalRead += bytesRead;
+                    totalRead += bytesRead;
+                }
             }
         }
 

src/ImageSharp/Memory/Allocators/Internals/Gen2GcCallback.cs

@@ -1,6 +1,5 @@
 // Copyright (c) Six Labors.
 // Licensed under the Six Labors Split License.
-#nullable disable
 
 // Port of BCL internal utility:
 // https://github.com/dotnet/runtime/blob/57bfe474518ab5b7cfe6bf7424a79ce3af9d6657/src/libraries/System.Private.CoreLib/src/System/Gen2GcCallback.cs
@@ -15,8 +14,8 @@ namespace SixLabors.ImageSharp.Memory.Internals;
 /// </summary>
 internal sealed class Gen2GcCallback : CriticalFinalizerObject
 {
-    private readonly Func<bool> callback0;
-    private readonly Func<object, bool> callback1;
+    private readonly Func<bool>? callback0;
+    private readonly Func<object, bool>? callback1;
     private GCHandle weakTargetObj;
 
     private Gen2GcCallback(Func<bool> callback) => this.callback0 = callback;
@@ -32,7 +31,7 @@ internal sealed class Gen2GcCallback : CriticalFinalizerObject
         if (this.weakTargetObj.IsAllocated)
         {
             // Check to see if the target object is still alive.
-            object targetObj = this.weakTargetObj.Target;
+            object? targetObj = this.weakTargetObj.Target;
             if (targetObj == null)
             {
                 // The target object is dead, so this callback object is no longer needed.
@@ -43,7 +42,7 @@ internal sealed class Gen2GcCallback : CriticalFinalizerObject
             // Execute the callback method.
             try
             {
-                if (!this.callback1(targetObj))
+                if (!this.callback1!(targetObj))
                 {
                     // If the callback returns false, this callback object is no longer needed.
                     this.weakTargetObj.Free();
@@ -64,7 +63,7 @@ internal sealed class Gen2GcCallback : CriticalFinalizerObject
             // Execute the callback method.
             try
             {
-                if (!this.callback0())
+                if (!this.callback0!())
                 {
                     // If the callback returns false, this callback object is no longer needed.
                     return;

src/ImageSharp/Memory/Allocators/Internals/RefCountedMemoryLifetimeGuard.cs

@@ -1,6 +1,5 @@
 // Copyright (c) Six Labors.
 // Licensed under the Six Labors Split License.
-#nullable disable
 
 using SixLabors.ImageSharp.Diagnostics;
 
@@ -15,7 +14,7 @@ internal abstract class RefCountedMemoryLifetimeGuard : IDisposable
     private int refCount = 1;
     private int disposed;
     private int released;
-    private string allocationStackTrace;
+    private string? allocationStackTrace;
 
     protected RefCountedMemoryLifetimeGuard()
     {

src/ImageSharp/Memory/Allocators/Internals/SharedArrayPoolBuffer{T}.cs

@@ -1,9 +1,9 @@
 // Copyright (c) Six Labors.
 // Licensed under the Six Labors Split License.
-#nullable disable
 
 using System.Buffers;
 using System.Diagnostics;
+using System.Diagnostics.CodeAnalysis;
 using System.Runtime.CompilerServices;
 using System.Runtime.InteropServices;
 
@@ -22,7 +22,7 @@ internal class SharedArrayPoolBuffer<T> : ManagedBufferBase<T>, IRefCounted
         this.lifetimeGuard = new LifetimeGuard(this.Array);
     }
 
-    public byte[] Array { get; private set; }
+    public byte[]? Array { get; private set; }
 
     protected override void Dispose(bool disposing)
     {
@@ -41,7 +41,11 @@ internal class SharedArrayPoolBuffer<T> : ManagedBufferBase<T>, IRefCounted
         return MemoryMarshal.Cast<byte, T>(this.Array.AsSpan(0, this.lengthInBytes));
     }
 
-    protected override object GetPinnableObject() => this.Array;
+    protected override object GetPinnableObject()
+    {
+        this.CheckDisposed();
+        return this.Array;
+    }
 
     public void AddRef()
     {
@@ -52,6 +56,7 @@ internal class SharedArrayPoolBuffer<T> : ManagedBufferBase<T>, IRefCounted
     public void ReleaseRef() => this.lifetimeGuard.ReleaseRef();
 
     [Conditional("DEBUG")]
+    [MemberNotNull(nameof(Array))]
     private void CheckDisposed()
     {
         if (this.Array == null)
@@ -62,7 +67,7 @@ internal class SharedArrayPoolBuffer<T> : ManagedBufferBase<T>, IRefCounted
 
     private sealed class LifetimeGuard : RefCountedMemoryLifetimeGuard
     {
-        private byte[] array;
+        private byte[]? array;
 
         public LifetimeGuard(byte[] array) => this.array = array;
 
@@ -73,7 +78,7 @@ internal class SharedArrayPoolBuffer<T> : ManagedBufferBase<T>, IRefCounted
             // This is not ideal, but subsequent leaks will end up returning arrays to per-cpu buckets,
             // meaning likely a different bucket than it was rented from,
             // but this is PROBABLY better than not returning the arrays at all.
-            ArrayPool<byte>.Shared.Return(this.array);
+            ArrayPool<byte>.Shared.Return(this.array!);
             this.array = null;
         }
     }

src/ImageSharp/Memory/Allocators/Internals/UniformUnmanagedMemoryPool.cs

@@ -1,6 +1,5 @@
 // Copyright (c) Six Labors.
 // Licensed under the Six Labors Split License.
-#nullable disable
 
 using System.Diagnostics;
 
@@ -13,7 +12,7 @@ internal partial class UniformUnmanagedMemoryPool : System.Runtime.ConstrainedEx
 {
     private static int minTrimPeriodMilliseconds = int.MaxValue;
     private static readonly List<WeakReference<UniformUnmanagedMemoryPool>> AllPools = new();
-    private static Timer trimTimer;
+    private static Timer? trimTimer;
 
     private static readonly Stopwatch Stopwatch = Stopwatch.StartNew();
 
@@ -97,7 +96,7 @@ internal partial class UniformUnmanagedMemoryPool : System.Runtime.ConstrainedEx
     /// <summary>
     /// Rent <paramref name="bufferCount"/> buffers or return 'null' if the pool is full.
     /// </summary>
-    public UnmanagedMemoryHandle[] Rent(int bufferCount)
+    public UnmanagedMemoryHandle[]? Rent(int bufferCount)
     {
         UnmanagedMemoryHandle[] buffersLocal = this.buffers;
 
@@ -248,7 +247,7 @@ internal partial class UniformUnmanagedMemoryPool : System.Runtime.ConstrainedEx
 
             foreach (WeakReference<UniformUnmanagedMemoryPool> weakPoolRef in AllPools)
             {
-                if (weakPoolRef.TryGetTarget(out UniformUnmanagedMemoryPool pool))
+                if (weakPoolRef.TryGetTarget(out UniformUnmanagedMemoryPool? pool))
                 {
                     pool.Trim();
                 }

src/ImageSharp/Memory/Allocators/Internals/UnmanagedMemoryHandle.cs

@@ -1,6 +1,5 @@
 // Copyright (c) Six Labors.
 // Licensed under the Six Labors Split License.
-#nullable disable
 
 using System.Runtime.InteropServices;
 
@@ -20,7 +19,7 @@ internal struct UnmanagedMemoryHandle : IEquatable<UnmanagedMemoryHandle>
     private static long totalOomRetries;
 
     // A Monitor to wait/signal when we are low on memory.
-    private static object lowMemoryMonitor;
+    private static object? lowMemoryMonitor;
 
     public static readonly UnmanagedMemoryHandle NullHandle;
 
@@ -114,9 +113,9 @@ internal struct UnmanagedMemoryHandle : IEquatable<UnmanagedMemoryHandle>
         if (Volatile.Read(ref lowMemoryMonitor) != null)
         {
             // We are low on memory. Signal all threads waiting in AllocateHandle().
-            Monitor.Enter(lowMemoryMonitor);
-            Monitor.PulseAll(lowMemoryMonitor);
-            Monitor.Exit(lowMemoryMonitor);
+            Monitor.Enter(lowMemoryMonitor!);
+            Monitor.PulseAll(lowMemoryMonitor!);
+            Monitor.Exit(lowMemoryMonitor!);
         }
 
         this.lengthInBytes = 0;
@@ -124,7 +123,7 @@ internal struct UnmanagedMemoryHandle : IEquatable<UnmanagedMemoryHandle>
 
     public bool Equals(UnmanagedMemoryHandle other) => this.handle.Equals(other.handle);
 
-    public override bool Equals(object obj) => obj is UnmanagedMemoryHandle other && this.Equals(other);
+    public override bool Equals(object? obj) => obj is UnmanagedMemoryHandle other && this.Equals(other);
 
     public override int GetHashCode() => this.handle.GetHashCode();
 }

src/ImageSharp/Memory/Allocators/UniformUnmanagedMemoryPoolMemoryAllocator.cs

@@ -135,7 +135,7 @@ internal sealed class UniformUnmanagedMemoryPoolMemoryAllocator : MemoryAllocato
         }
 
         // Attempt to rent the whole group from the pool, allocate a group of unmanaged buffers if the attempt fails:
-        if (MemoryGroup<T>.TryAllocate(this.pool, totalLength, bufferAlignment, options, out MemoryGroup<T> poolGroup))
+        if (MemoryGroup<T>.TryAllocate(this.pool, totalLength, bufferAlignment, options, out MemoryGroup<T>? poolGroup))
         {
             return poolGroup;
         }

src/ImageSharp/Memory/DiscontiguousBuffers/MemoryGroupExtensions.cs

@@ -106,7 +106,7 @@ internal static class MemoryGroupExtensions
         }
     }
 
-    internal static void CopyTo<T>(this IMemoryGroup<T> source, IMemoryGroup<T> target)
+    internal static void CopyTo<T>(this IMemoryGroup<T>? source, IMemoryGroup<T>? target)
         where T : struct
     {
         Guard.NotNull(source, nameof(source));

src/ImageSharp/Memory/DiscontiguousBuffers/MemoryGroupSpanCache.cs

@@ -13,7 +13,7 @@ namespace SixLabors.ImageSharp.Memory;
 internal unsafe struct MemoryGroupSpanCache
 {
     public SpanCacheMode Mode;
-    public byte[] SingleArray;
+    public byte[]? SingleArray;
     public void* SinglePointer;
     public void*[] MultiPointer;
 

src/ImageSharp/Memory/DiscontiguousBuffers/MemoryGroupView{T}.cs

@@ -1,9 +1,9 @@
 // Copyright (c) Six Labors.
 // Licensed under the Six Labors Split License.
-#nullable disable
 
 using System.Buffers;
 using System.Collections;
+using System.Diagnostics.CodeAnalysis;
 using System.Runtime.CompilerServices;
 
 namespace SixLabors.ImageSharp.Memory;
@@ -21,7 +21,7 @@ namespace SixLabors.ImageSharp.Memory;
 internal class MemoryGroupView<T> : IMemoryGroup<T>
     where T : struct
 {
-    private MemoryGroup<T> owner;
+    private MemoryGroup<T>? owner;
     private readonly MemoryOwnerWrapper[] memoryWrappers;
 
     public MemoryGroupView(MemoryGroup<T> owner)
@@ -63,6 +63,7 @@ internal class MemoryGroupView<T> : IMemoryGroup<T>
         }
     }
 
+    [MemberNotNullWhen(true, nameof(owner))]
     public bool IsValid => this.owner != null;
 
     public Memory<T> this[int index]
@@ -99,6 +100,7 @@ internal class MemoryGroupView<T> : IMemoryGroup<T>
         this.owner = null;
     }
 
+    [MemberNotNull(nameof(owner))]
     private void EnsureIsValid()
     {
         if (!this.IsValid)

src/ImageSharp/Memory/DiscontiguousBuffers/MemoryGroup{T}.Owned.cs

@@ -1,8 +1,8 @@
 // Copyright (c) Six Labors.
 // Licensed under the Six Labors Split License.
-#nullable disable
 
 using System.Buffers;
+using System.Diagnostics.CodeAnalysis;
 using System.Runtime.CompilerServices;
 using SixLabors.ImageSharp.Memory.Internals;
 
@@ -15,8 +15,8 @@ internal abstract partial class MemoryGroup<T>
     /// </summary>
     public sealed class Owned : MemoryGroup<T>, IEnumerable<Memory<T>>
     {
-        private IMemoryOwner<T>[] memoryOwners;
-        private RefCountedMemoryLifetimeGuard groupLifetimeGuard;
+        private IMemoryOwner<T>[]? memoryOwners;
+        private RefCountedMemoryLifetimeGuard? groupLifetimeGuard;
 
         public Owned(IMemoryOwner<T>[] memoryOwners, int bufferLength, long totalLength, bool swappable)
             : base(bufferLength, totalLength)
@@ -149,7 +149,7 @@ internal abstract partial class MemoryGroup<T>
             }
             else
             {
-                foreach (IMemoryOwner<T> memoryOwner in this.memoryOwners)
+                foreach (IMemoryOwner<T> memoryOwner in this.memoryOwners!)
                 {
                     memoryOwner.Dispose();
                 }
@@ -161,6 +161,7 @@ internal abstract partial class MemoryGroup<T>
         }
 
         [MethodImpl(InliningOptions.ShortMethod)]
+        [MemberNotNull(nameof(memoryOwners))]
         private void EnsureNotDisposed()
         {
             if (this.memoryOwners is null)
@@ -170,6 +171,7 @@ internal abstract partial class MemoryGroup<T>
         }
 
         [MethodImpl(MethodImplOptions.NoInlining)]
+        [DoesNotReturn]
         private static void ThrowObjectDisposedException() => throw new ObjectDisposedException(nameof(MemoryGroup<T>));
 
         // When the MemoryGroup points to multiple buffers via `groupLifetimeGuard`,

src/ImageSharp/Memory/DiscontiguousBuffers/MemoryGroup{T}.cs

@@ -1,9 +1,9 @@
 // Copyright (c) Six Labors.
 // Licensed under the Six Labors Split License.
-#nullable disable
 
 using System.Buffers;
 using System.Collections;
+using System.Diagnostics.CodeAnalysis;
 using System.Runtime.CompilerServices;
 using System.Runtime.InteropServices;
 using SixLabors.ImageSharp.Memory.Internals;
@@ -41,7 +41,7 @@ internal abstract partial class MemoryGroup<T> : IMemoryGroup<T>, IDisposable
     /// <inheritdoc />
     public bool IsValid { get; private set; } = true;
 
-    public MemoryGroupView<T> View { get; private set; }
+    public MemoryGroupView<T> View { get; private set; } = null!;
 
     /// <inheritdoc />
     public abstract Memory<T> this[int index] { get; }
@@ -150,7 +150,7 @@ internal abstract partial class MemoryGroup<T> : IMemoryGroup<T>, IDisposable
         long totalLengthInElements,
         int bufferAlignmentInElements,
         AllocationOptions options,
-        out MemoryGroup<T> memoryGroup)
+        [NotNullWhen(true)] out MemoryGroup<T>? memoryGroup)
     {
         Guard.NotNull(pool, nameof(pool));
         Guard.MustBeGreaterThanOrEqualTo(totalLengthInElements, 0, nameof(totalLengthInElements));
@@ -188,7 +188,7 @@ internal abstract partial class MemoryGroup<T> : IMemoryGroup<T>, IDisposable
             bufferCount++;
         }
 
-        UnmanagedMemoryHandle[] arrays = pool.Rent(bufferCount);
+        UnmanagedMemoryHandle[]? arrays = pool.Rent(bufferCount);
 
         if (arrays == null)
         {

tests/ImageSharp.Benchmarks/Codecs/Jpeg/DecodeJpegParseStreamOnly.cs

@@ -54,6 +54,8 @@ public class DecodeJpegParseStreamOnly
         {
         }
 
+        public override bool HasPixelBuffer() => throw new NotImplementedException();
+
         public override void InjectFrameData(JpegFrame frame, IRawJpegData jpegData)
         {
         }

tests/ImageSharp.Tests/Formats/Jpg/JFifMarkerTests.cs

@@ -46,15 +46,6 @@ public class JFifMarkerTests
         Assert.Equal(default, marker);
     }
 
-    [Fact]
-    public void MarkerIgnoresCorrectHeaderButInvalidDensities()
-    {
-        bool isJFif = JFifMarker.TryParse(this.bytes3, out JFifMarker marker);
-
-        Assert.False(isJFif);
-        Assert.Equal(default, marker);
-    }
-
     [Fact]
     public void MarkerEqualityIsCorrect()
     {

tests/ImageSharp.Tests/Formats/Jpg/JpegDecoderTests.cs

@@ -300,4 +300,15 @@ public partial class JpegDecoderTests
         image.DebugSave(provider);
         image.CompareToOriginal(provider);
     }
+
+    // https://github.com/SixLabors/ImageSharp/issues/2315
+    [Theory]
+    [WithFile(TestImages.Jpeg.Issues.Issue2315_NotEnoughBytes, PixelTypes.Rgba32)]
+    public void Issue2315_DecodeWorks<TPixel>(TestImageProvider<TPixel> provider)
+        where TPixel : unmanaged, IPixel<TPixel>
+    {
+        using Image<TPixel> image = provider.GetImage(JpegDecoder.Instance);
+        image.DebugSave(provider);
+        image.CompareToOriginal(provider);
+    }
 }

tests/ImageSharp.Tests/Formats/Jpg/SpectralJpegTests.cs

@@ -187,6 +187,8 @@ public class SpectralJpegTests
             }
         }
 
+        public override bool HasPixelBuffer() => throw new NotImplementedException();
+
         public override void InjectFrameData(JpegFrame frame, IRawJpegData jpegData)
         {
             this.frame = frame;

tests/ImageSharp.Tests/TestImages.cs

@@ -281,6 +281,7 @@ public static class TestImages
             public const string ValidExifArgumentNullExceptionOnEncode = "Jpg/issues/Issue2087-exif-null-reference-on-encode.jpg";
             public const string Issue2133_DeduceColorSpace = "Jpg/issues/Issue2133.jpg";
             public const string Issue2136_ScanMarkerExtraneousBytes = "Jpg/issues/Issue2136-scan-segment-extraneous-bytes.jpg";
+            public const string Issue2315_NotEnoughBytes = "Jpg/issues/issue-2315.jpg";
 
             public static class Fuzz
             {

tests/Images/Input/Jpg/issues/issue-2315.jpg

@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:f129b057efb499d492e9afcffdd98de62aac1e04b97a09a75b4799ba498cd3c1
+size 319056