Merge branch 'release/2.1' into release/2.2

NuGetPackageVerifier.json

@@ -1,7 +1,14 @@
 {
-    "Default": {
-        "rules": [
-            "DefaultCompositeRule"
-        ]
+  "nonshipping": {
+    "rules": [],
+    "packages": {
+      "Microsoft.Extensions.Buffers.MemoryPool.Sources": {},
+      "Microsoft.Extensions.Buffers.Testing.Sources": {}
     }
-}
+  },
+  "Default": {
+    "rules": [
+      "DefaultCompositeRule"
+    ]
+  }
+}

build/dependencies.props

@@ -19,9 +19,6 @@
     <MicrosoftAspNetCoreTestingPackageVersion>2.2.0-preview1-34755</MicrosoftAspNetCoreTestingPackageVersion>
     <MicrosoftAspNetCoreWebUtilitiesPackageVersion>2.2.0-preview1-34755</MicrosoftAspNetCoreWebUtilitiesPackageVersion>
     <MicrosoftExtensionsActivatorUtilitiesSourcesPackageVersion>2.2.0-preview1-34755</MicrosoftExtensionsActivatorUtilitiesSourcesPackageVersion>
-    <MicrosoftExtensionsBuffersMemoryPoolSourcesPackageVersion>2.2.0-preview1-34755</MicrosoftExtensionsBuffersMemoryPoolSourcesPackageVersion>
-    <MicrosoftExtensionsBuffersSourcesPackageVersion>2.2.0-preview1-34755</MicrosoftExtensionsBuffersSourcesPackageVersion>
-    <MicrosoftExtensionsBuffersTestingSourcesPackageVersion>2.2.0-preview1-34755</MicrosoftExtensionsBuffersTestingSourcesPackageVersion>
     <MicrosoftExtensionsConfigurationBinderPackageVersion>2.2.0-preview1-34755</MicrosoftExtensionsConfigurationBinderPackageVersion>
     <MicrosoftExtensionsConfigurationCommandLinePackageVersion>2.2.0-preview1-34755</MicrosoftExtensionsConfigurationCommandLinePackageVersion>
     <MicrosoftExtensionsConfigurationJsonPackageVersion>2.2.0-preview1-34755</MicrosoftExtensionsConfigurationJsonPackageVersion>

shared/Microsoft.Extensions.Buffers.MemoryPool.Sources/DiagnosticMemoryPool.cs

@@ -0,0 +1,165 @@
+// Copyright (c) Microsoft. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license information.
+
+using System.Collections.Generic;
+using System.Linq;
+using System.Threading.Tasks;
+
+namespace System.Buffers
+{
+    /// <summary>
+    /// Used to allocate and distribute re-usable blocks of memory.
+    /// </summary>
+    internal class DiagnosticMemoryPool : MemoryPool<byte>
+    {
+        private readonly MemoryPool<byte> _pool;
+
+        private readonly bool _allowLateReturn;
+
+        private readonly bool _rentTracking;
+
+        private readonly object _syncObj;
+
+        private readonly HashSet<DiagnosticPoolBlock> _blocks;
+
+        private readonly List<Exception> _blockAccessExceptions;
+
+        private readonly TaskCompletionSource<object> _allBlocksRetuned;
+
+        private int _totalBlocks;
+
+        /// <summary>
+        /// This default value passed in to Rent to use the default value for the pool.
+        /// </summary>
+        private const int AnySize = -1;
+
+        public DiagnosticMemoryPool(MemoryPool<byte> pool, bool allowLateReturn = false, bool rentTracking = false)
+        {
+            _pool = pool;
+            _allowLateReturn = allowLateReturn;
+            _rentTracking = rentTracking;
+            _blocks = new HashSet<DiagnosticPoolBlock>();
+            _syncObj = new object();
+            _allBlocksRetuned = new TaskCompletionSource<object>();
+            _blockAccessExceptions = new List<Exception>();
+        }
+
+        public bool IsDisposed { get; private set; }
+
+        public override IMemoryOwner<byte> Rent(int size = AnySize)
+        {
+            lock (_syncObj)
+            {
+                if (IsDisposed)
+                {
+                    MemoryPoolThrowHelper.ThrowObjectDisposedException(MemoryPoolThrowHelper.ExceptionArgument.MemoryPool);
+                }
+
+                var diagnosticPoolBlock = new DiagnosticPoolBlock(this, _pool.Rent(size));
+                if (_rentTracking)
+                {
+                    diagnosticPoolBlock.Track();
+                }
+                _totalBlocks++;
+                _blocks.Add(diagnosticPoolBlock);
+                return diagnosticPoolBlock;
+            }
+        }
+
+        public override int MaxBufferSize => _pool.MaxBufferSize;
+
+        internal void Return(DiagnosticPoolBlock block)
+        {
+            bool returnedAllBlocks;
+            lock (_syncObj)
+            {
+                _blocks.Remove(block);
+                returnedAllBlocks = _blocks.Count == 0;
+            }
+
+            if (IsDisposed)
+            {
+                if (!_allowLateReturn)
+                {
+                    MemoryPoolThrowHelper.ThrowInvalidOperationException_BlockReturnedToDisposedPool(block);
+                }
+
+                if (returnedAllBlocks)
+                {
+                    SetAllBlocksReturned();
+                }
+            }
+
+        }
+
+        internal void ReportException(Exception exception)
+        {
+            lock (_syncObj)
+            {
+                _blockAccessExceptions.Add(exception);
+            }
+        }
+
+        protected override void Dispose(bool disposing)
+        {
+            if (IsDisposed)
+            {
+                MemoryPoolThrowHelper.ThrowInvalidOperationException_DoubleDispose();
+            }
+
+            bool allBlocksReturned = false;
+            try
+            {
+                lock (_syncObj)
+                {
+                    IsDisposed = true;
+                    allBlocksReturned = _blocks.Count == 0;
+                    if (!allBlocksReturned && !_allowLateReturn)
+                    {
+                        MemoryPoolThrowHelper.ThrowInvalidOperationException_DisposingPoolWithActiveBlocks(_totalBlocks - _blocks.Count, _totalBlocks, _blocks.ToArray());
+                    }
+
+                    if (_blockAccessExceptions.Any())
+                    {
+                        throw CreateAccessExceptions();
+                    }
+                }
+            }
+            finally
+            {
+                if (allBlocksReturned)
+                {
+                    SetAllBlocksReturned();
+                }
+            }
+        }
+
+        private void SetAllBlocksReturned()
+        {
+            if (_blockAccessExceptions.Any())
+            {
+                _allBlocksRetuned.SetException(CreateAccessExceptions());
+            }
+            else
+            {
+                _allBlocksRetuned.SetResult(null);
+            }
+        }
+
+        private AggregateException CreateAccessExceptions()
+        {
+            return new AggregateException("Exceptions occurred while accessing blocks", _blockAccessExceptions.ToArray());
+        }
+
+        public async Task WhenAllBlocksReturnedAsync(TimeSpan timeout)
+        {
+            var task = await Task.WhenAny(_allBlocksRetuned.Task, Task.Delay(timeout));
+            if (task != _allBlocksRetuned.Task)
+            {
+                MemoryPoolThrowHelper.ThrowInvalidOperationException_BlocksWereNotReturnedInTime(_totalBlocks - _blocks.Count, _totalBlocks, _blocks.ToArray());
+            }
+
+            await task;
+        }
+    }
+}

shared/Microsoft.Extensions.Buffers.MemoryPool.Sources/DiagnosticPoolBlock.cs

@@ -0,0 +1,224 @@
+// Copyright (c) Microsoft. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license information.
+
+using System.Threading;
+using System.Diagnostics;
+using System.Runtime.InteropServices;
+
+namespace System.Buffers
+{
+    /// <summary>
+    /// Block tracking object used by the byte buffer memory pool. A slab is a large allocation which is divided into smaller blocks. The
+    /// individual blocks are then treated as independent array segments.
+    /// </summary>
+    internal sealed class DiagnosticPoolBlock : MemoryManager<byte>
+    {
+        /// <summary>
+        /// Back-reference to the memory pool which this block was allocated from. It may only be returned to this pool.
+        /// </summary>
+        private readonly DiagnosticMemoryPool _pool;
+
+        private readonly IMemoryOwner<byte> _memoryOwner;
+        private MemoryHandle? _memoryHandle;
+        private Memory<byte> _memory;
+
+        private readonly object _syncObj = new object();
+        private bool _isDisposed;
+        private int _pinCount;
+
+
+        /// <summary>
+        /// This object cannot be instantiated outside of the static Create method
+        /// </summary>
+        internal DiagnosticPoolBlock(DiagnosticMemoryPool pool, IMemoryOwner<byte> memoryOwner)
+        {
+            _pool = pool;
+            _memoryOwner = memoryOwner;
+            _memory = memoryOwner.Memory;
+        }
+
+        public override Memory<byte> Memory
+        {
+            get
+            {
+                try
+                {
+                    lock (_syncObj)
+                    {
+                        if (_isDisposed)
+                        {
+                            MemoryPoolThrowHelper.ThrowObjectDisposedException(MemoryPoolThrowHelper.ExceptionArgument.MemoryPoolBlock);
+                        }
+
+                        if (_pool.IsDisposed)
+                        {
+                            MemoryPoolThrowHelper.ThrowInvalidOperationException_BlockIsBackedByDisposedSlab(this);
+                        }
+
+                        return CreateMemory(_memory.Length);
+                    }
+                }
+                catch (Exception exception)
+                {
+                    _pool.ReportException(exception);
+                    throw;
+                }
+            }
+        }
+
+        protected override void Dispose(bool disposing)
+        {
+            try
+            {
+                lock (_syncObj)
+                {
+                    if (Volatile.Read(ref _pinCount) > 0)
+                    {
+                        MemoryPoolThrowHelper.ThrowInvalidOperationException_ReturningPinnedBlock(this);
+                    }
+
+                    if (_isDisposed)
+                    {
+                        MemoryPoolThrowHelper.ThrowInvalidOperationException_BlockDoubleDispose(this);
+                    }
+
+                    _memoryOwner.Dispose();
+
+                    _pool.Return(this);
+
+                    _isDisposed = true;
+                }
+            }
+            catch (Exception exception)
+            {
+                _pool.ReportException(exception);
+                throw;
+            }
+        }
+
+        public override Span<byte> GetSpan()
+        {
+            try
+            {
+                lock (_syncObj)
+                {
+                    if (_isDisposed)
+                    {
+                        MemoryPoolThrowHelper.ThrowObjectDisposedException(MemoryPoolThrowHelper.ExceptionArgument.MemoryPoolBlock);
+                    }
+
+                    if (_pool.IsDisposed)
+                    {
+                        MemoryPoolThrowHelper.ThrowInvalidOperationException_BlockIsBackedByDisposedSlab(this);
+                    }
+
+                    return _memory.Span;
+                }
+            }
+            catch (Exception exception)
+            {
+                _pool.ReportException(exception);
+                throw;
+            }
+        }
+
+        public override MemoryHandle Pin(int byteOffset = 0)
+        {
+            try
+            {
+                lock (_syncObj)
+                {
+                    if (_isDisposed)
+                    {
+                        MemoryPoolThrowHelper.ThrowObjectDisposedException(MemoryPoolThrowHelper.ExceptionArgument.MemoryPoolBlock);
+                    }
+
+                    if (_pool.IsDisposed)
+                    {
+                        MemoryPoolThrowHelper.ThrowInvalidOperationException_BlockIsBackedByDisposedSlab(this);
+                    }
+
+                    if (byteOffset < 0 || byteOffset > _memory.Length)
+                    {
+                        MemoryPoolThrowHelper.ThrowArgumentOutOfRangeException(_memory.Length, byteOffset);
+                    }
+
+                    _pinCount++;
+
+                    _memoryHandle = _memoryHandle ?? _memory.Pin();
+
+                    unsafe
+                    {
+                        return new MemoryHandle(((IntPtr)_memoryHandle.Value.Pointer + byteOffset).ToPointer(), default, this);
+                    }
+                }
+            }
+            catch (Exception exception)
+            {
+                _pool.ReportException(exception);
+                throw;
+            }
+        }
+
+        protected override bool TryGetArray(out ArraySegment<byte> segment)
+        {
+            try
+            {
+                lock (_syncObj)
+                {
+                    if (_isDisposed)
+                    {
+                        MemoryPoolThrowHelper.ThrowObjectDisposedException(MemoryPoolThrowHelper.ExceptionArgument.MemoryPoolBlock);
+                    }
+
+                    if (_pool.IsDisposed)
+                    {
+                        MemoryPoolThrowHelper.ThrowInvalidOperationException_BlockIsBackedByDisposedSlab(this);
+                    }
+
+                    return MemoryMarshal.TryGetArray(_memory, out segment);
+                }
+            }
+            catch (Exception exception)
+            {
+                _pool.ReportException(exception);
+                throw;
+            }
+        }
+
+        public override void Unpin()
+        {
+            try
+            {
+                lock (_syncObj)
+                {
+                    if (_pinCount == 0)
+                    {
+                        MemoryPoolThrowHelper.ThrowInvalidOperationException_PinCountZero(this);
+                    }
+
+                    _pinCount--;
+
+                    if (_pinCount == 0)
+                    {
+                        Debug.Assert(_memoryHandle.HasValue);
+                        _memoryHandle.Value.Dispose();
+                        _memoryHandle = null;
+                    }
+                }
+            }
+            catch (Exception exception)
+            {
+                _pool.ReportException(exception);
+                throw;
+            }
+        }
+
+        public StackTrace Leaser { get; set; }
+
+        public void Track()
+        {
+            Leaser = new StackTrace(false);
+        }
+    }
+}

shared/Microsoft.Extensions.Buffers.MemoryPool.Sources/MemoryPoolBlock.cs

@@ -0,0 +1,61 @@
+// Copyright (c) Microsoft. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license information.
+
+using System.Runtime.InteropServices;
+
+namespace System.Buffers
+{
+    /// <summary>
+    /// Block tracking object used by the byte buffer memory pool. A slab is a large allocation which is divided into smaller blocks. The
+    /// individual blocks are then treated as independent array segments.
+    /// </summary>
+    internal sealed class MemoryPoolBlock : IMemoryOwner<byte>
+    {
+        private readonly int _offset;
+        private readonly int _length;
+
+        /// <summary>
+        /// This object cannot be instantiated outside of the static Create method
+        /// </summary>
+        internal MemoryPoolBlock(SlabMemoryPool pool, MemoryPoolSlab slab, int offset, int length)
+        {
+            _offset = offset;
+            _length = length;
+
+            Pool = pool;
+            Slab = slab;
+
+            Memory = MemoryMarshal.CreateFromPinnedArray(slab.Array, _offset, _length);
+        }
+
+        /// <summary>
+        /// Back-reference to the memory pool which this block was allocated from. It may only be returned to this pool.
+        /// </summary>
+        public SlabMemoryPool Pool { get; }
+
+        /// <summary>
+        /// Back-reference to the slab from which this block was taken, or null if it is one-time-use memory.
+        /// </summary>
+        public MemoryPoolSlab Slab { get; }
+
+        public Memory<byte> Memory { get; }
+
+        ~MemoryPoolBlock()
+        {
+            if (Slab != null && Slab.IsActive)
+            {
+                // Need to make a new object because this one is being finalized
+                Pool.Return(new MemoryPoolBlock(Pool, Slab, _offset, _length));
+            }
+        }
+
+        public void Dispose()
+        {
+            Pool.Return(this);
+        }
+
+        public void Lease()
+        {
+        }
+    }
+}

shared/Microsoft.Extensions.Buffers.MemoryPool.Sources/MemoryPoolSlab.cs

@@ -0,0 +1,80 @@
+// Copyright (c) Microsoft. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license information.
+
+using System.Runtime.InteropServices;
+
+namespace System.Buffers
+{
+    /// <summary>
+    /// Slab tracking object used by the byte buffer memory pool. A slab is a large allocation which is divided into smaller blocks. The
+    /// individual blocks are then treated as independant array segments.
+    /// </summary>
+    internal class MemoryPoolSlab : IDisposable
+    {
+        /// <summary>
+        /// This handle pins the managed array in memory until the slab is disposed. This prevents it from being
+        /// relocated and enables any subsections of the array to be used as native memory pointers to P/Invoked API calls.
+        /// </summary>
+        private GCHandle _gcHandle;
+        private bool _isDisposed;
+
+        public MemoryPoolSlab(byte[] data)
+        {
+            Array = data;
+            _gcHandle = GCHandle.Alloc(data, GCHandleType.Pinned);
+            NativePointer = _gcHandle.AddrOfPinnedObject();
+        }
+
+        /// <summary>
+        /// True as long as the blocks from this slab are to be considered returnable to the pool. In order to shrink the
+        /// memory pool size an entire slab must be removed. That is done by (1) setting IsActive to false and removing the
+        /// slab from the pool's _slabs collection, (2) as each block currently in use is Return()ed to the pool it will
+        /// be allowed to be garbage collected rather than re-pooled, and (3) when all block tracking objects are garbage
+        /// collected and the slab is no longer references the slab will be garbage collected and the memory unpinned will
+        /// be unpinned by the slab's Dispose.
+        /// </summary>
+        public bool IsActive => !_isDisposed;
+
+        public IntPtr NativePointer { get; private set; }
+
+        public byte[] Array { get; private set; }
+
+        public static MemoryPoolSlab Create(int length)
+        {
+            // allocate and pin requested memory length
+            var array = new byte[length];
+
+            // allocate and return slab tracking object
+            return new MemoryPoolSlab(array);
+        }
+
+        protected void Dispose(bool disposing)
+        {
+            if (_isDisposed)
+            {
+                return;
+            }
+
+            _isDisposed = true;
+
+            Array = null;
+            NativePointer = IntPtr.Zero;;
+
+            if (_gcHandle.IsAllocated)
+            {
+                _gcHandle.Free();
+            }
+        }
+
+        ~MemoryPoolSlab()
+        {
+            Dispose(false);
+        }
+
+        public void Dispose()
+        {
+            Dispose(true);
+            GC.SuppressFinalize(this);
+        }
+    }
+}

shared/Microsoft.Extensions.Buffers.MemoryPool.Sources/MemoryPoolThrowHelper.cs

@@ -0,0 +1,125 @@
+// Copyright (c) Microsoft. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license information.
+
+using System.Diagnostics;
+using System.Runtime.CompilerServices;
+using System.Text;
+
+namespace System.Buffers
+{
+    internal class MemoryPoolThrowHelper
+    {
+        public static void ThrowArgumentOutOfRangeException(int sourceLength, int offset)
+        {
+            throw GetArgumentOutOfRangeException(sourceLength, offset);
+        }
+
+        [MethodImpl(MethodImplOptions.NoInlining)]
+        private static ArgumentOutOfRangeException GetArgumentOutOfRangeException(int sourceLength, int offset)
+        {
+            if ((uint)offset > (uint)sourceLength)
+            {
+                // Offset is negative or less than array length
+                return new ArgumentOutOfRangeException(GetArgumentName(ExceptionArgument.offset));
+            }
+
+            // The third parameter (not passed) length must be out of range
+            return new ArgumentOutOfRangeException(GetArgumentName(ExceptionArgument.length));
+        }
+
+        public static void ThrowInvalidOperationException_PinCountZero(DiagnosticPoolBlock block)
+        {
+            throw new InvalidOperationException(GenerateMessage("Can't unpin, pin count is zero", block));
+        }
+
+        public static void ThrowInvalidOperationException_ReturningPinnedBlock(DiagnosticPoolBlock block)
+        {
+            throw new InvalidOperationException(GenerateMessage("Disposing pinned block", block));
+        }
+
+        public static void ThrowInvalidOperationException_DoubleDispose()
+        {
+            throw new InvalidOperationException("Object is being disposed twice");
+        }
+
+        public static void ThrowInvalidOperationException_BlockDoubleDispose(DiagnosticPoolBlock block)
+        {
+            throw new InvalidOperationException("Block is being disposed twice");
+        }
+
+        public static void ThrowInvalidOperationException_BlockReturnedToDisposedPool(DiagnosticPoolBlock block)
+        {
+            throw new InvalidOperationException(GenerateMessage("Block is being returned to disposed pool", block));
+        }
+
+        public static void ThrowInvalidOperationException_BlockIsBackedByDisposedSlab(DiagnosticPoolBlock block)
+        {
+            throw new InvalidOperationException(GenerateMessage("Block is backed by disposed slab", block));
+        }
+
+        public static void ThrowInvalidOperationException_DisposingPoolWithActiveBlocks(int returned, int total, DiagnosticPoolBlock[] blocks)
+        {
+            throw new InvalidOperationException(GenerateMessage($"Memory pool with active blocks is being disposed, {returned} of {total} returned", blocks));
+        }
+
+        public static void ThrowInvalidOperationException_BlocksWereNotReturnedInTime(int returned, int total, DiagnosticPoolBlock[] blocks)
+        {
+            throw new InvalidOperationException(GenerateMessage($"Blocks were not returned in time, {returned} of {total} returned ", blocks));
+        }
+
+        private static string GenerateMessage(string message, params DiagnosticPoolBlock[] blocks)
+        {
+            StringBuilder builder = new StringBuilder(message);
+            foreach (var diagnosticPoolBlock in blocks)
+            {
+                if (diagnosticPoolBlock.Leaser != null)
+                {
+                    builder.AppendLine();
+
+                    builder.AppendLine("Block leased from:");
+                    builder.AppendLine(diagnosticPoolBlock.Leaser.ToString());
+                }
+            }
+
+            return builder.ToString();
+        }
+
+        public static void ThrowArgumentOutOfRangeException_BufferRequestTooLarge(int maxSize)
+        {
+            throw GetArgumentOutOfRangeException_BufferRequestTooLarge(maxSize);
+        }
+
+        public static void ThrowObjectDisposedException(ExceptionArgument argument)
+        {
+            throw GetObjectDisposedException(argument);
+        }
+
+        [MethodImpl(MethodImplOptions.NoInlining)]
+        private static ArgumentOutOfRangeException GetArgumentOutOfRangeException_BufferRequestTooLarge(int maxSize)
+        {
+            return new ArgumentOutOfRangeException(GetArgumentName(ExceptionArgument.size), $"Cannot allocate more than {maxSize} bytes in a single buffer");
+        }
+
+        [MethodImpl(MethodImplOptions.NoInlining)]
+        private static ObjectDisposedException GetObjectDisposedException(ExceptionArgument argument)
+        {
+            return new ObjectDisposedException(GetArgumentName(argument));
+        }
+
+        private static string GetArgumentName(ExceptionArgument argument)
+        {
+            Debug.Assert(Enum.IsDefined(typeof(ExceptionArgument), argument), "The enum value is not defined, please check the ExceptionArgument Enum.");
+
+            return argument.ToString();
+        }
+
+        internal enum ExceptionArgument
+        {
+            size,
+            offset,
+            length,
+            MemoryPoolBlock,
+            MemoryPool
+        }
+    }
+}

shared/Microsoft.Extensions.Buffers.MemoryPool.Sources/SlabMemoryPool.cs

@@ -0,0 +1,191 @@
+// Copyright (c) Microsoft. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license information.
+
+using System.Collections.Concurrent;
+using System.Diagnostics;
+using System.Threading;
+
+namespace System.Buffers
+{
+    /// <summary>
+    /// Used to allocate and distribute re-usable blocks of memory.
+    /// </summary>
+    internal class SlabMemoryPool : MemoryPool<byte>
+    {
+        /// <summary>
+        /// The size of a block. 4096 is chosen because most operating systems use 4k pages.
+        /// </summary>
+        private const int _blockSize = 4096;
+
+        /// <summary>
+        /// Allocating 32 contiguous blocks per slab makes the slab size 128k. This is larger than the 85k size which will place the memory
+        /// in the large object heap. This means the GC will not try to relocate this array, so the fact it remains pinned does not negatively
+        /// affect memory management's compactification.
+        /// </summary>
+        private const int _blockCount = 32;
+
+        /// <summary>
+        /// Max allocation block size for pooled blocks,
+        /// larger values can be leased but they will be disposed after use rather than returned to the pool.
+        /// </summary>
+        public override int MaxBufferSize { get; } = _blockSize;
+
+        /// <summary>
+        /// 4096 * 32 gives you a slabLength of 128k contiguous bytes allocated per slab
+        /// </summary>
+        private static readonly int _slabLength = _blockSize * _blockCount;
+
+        /// <summary>
+        /// Thread-safe collection of blocks which are currently in the pool. A slab will pre-allocate all of the block tracking objects
+        /// and add them to this collection. When memory is requested it is taken from here first, and when it is returned it is re-added.
+        /// </summary>
+        private readonly ConcurrentQueue<MemoryPoolBlock> _blocks = new ConcurrentQueue<MemoryPoolBlock>();
+
+        /// <summary>
+        /// Thread-safe collection of slabs which have been allocated by this pool. As long as a slab is in this collection and slab.IsActive,
+        /// the blocks will be added to _blocks when returned.
+        /// </summary>
+        private readonly ConcurrentStack<MemoryPoolSlab> _slabs = new ConcurrentStack<MemoryPoolSlab>();
+
+        /// <summary>
+        /// This is part of implementing the IDisposable pattern.
+        /// </summary>
+        private bool _isDisposed; // To detect redundant calls
+
+        private int _totalAllocatedBlocks;
+
+        private readonly object _disposeSync = new object();
+
+        /// <summary>
+        /// This default value passed in to Rent to use the default value for the pool.
+        /// </summary>
+        private const int AnySize = -1;
+
+        public override IMemoryOwner<byte> Rent(int size = AnySize)
+        {
+            if (size > _blockSize)
+            {
+                MemoryPoolThrowHelper.ThrowArgumentOutOfRangeException_BufferRequestTooLarge(_blockSize);
+            }
+
+            var block = Lease();
+            return block;
+        }
+
+        /// <summary>
+        /// Called to take a block from the pool.
+        /// </summary>
+        /// <returns>The block that is reserved for the called. It must be passed to Return when it is no longer being used.</returns>
+        private MemoryPoolBlock Lease()
+        {
+            if (_isDisposed)
+            {
+                MemoryPoolThrowHelper.ThrowObjectDisposedException(MemoryPoolThrowHelper.ExceptionArgument.MemoryPool);
+            }
+
+            if (_blocks.TryDequeue(out MemoryPoolBlock block))
+            {
+                // block successfully taken from the stack - return it
+
+                block.Lease();
+                return block;
+            }
+            // no blocks available - grow the pool
+            block = AllocateSlab();
+            block.Lease();
+            return block;
+        }
+
+        /// <summary>
+        /// Internal method called when a block is requested and the pool is empty. It allocates one additional slab, creates all of the
+        /// block tracking objects, and adds them all to the pool.
+        /// </summary>
+        private MemoryPoolBlock AllocateSlab()
+        {
+            var slab = MemoryPoolSlab.Create(_slabLength);
+            _slabs.Push(slab);
+
+            var basePtr = slab.NativePointer;
+            // Page align the blocks
+            var offset = (int)((((ulong)basePtr + (uint)_blockSize - 1) & ~((uint)_blockSize - 1)) - (ulong)basePtr);
+            // Ensure page aligned
+            Debug.Assert(((ulong)basePtr + (uint)offset) % _blockSize == 0);
+
+            var blockCount = (_slabLength - offset) / _blockSize;
+            Interlocked.Add(ref _totalAllocatedBlocks, blockCount);
+
+            MemoryPoolBlock block = null;
+
+            for (int i = 0; i < blockCount; i++)
+            {
+                block = new MemoryPoolBlock(this, slab, offset, _blockSize);
+
+                if (i != blockCount - 1) // last block
+                {
+#if BLOCK_LEASE_TRACKING
+                    block.IsLeased = true;
+#endif
+                    Return(block);
+                }
+
+                offset += _blockSize;
+            }
+
+            return block;
+        }
+
+        /// <summary>
+        /// Called to return a block to the pool. Once Return has been called the memory no longer belongs to the caller, and
+        /// Very Bad Things will happen if the memory is read of modified subsequently. If a caller fails to call Return and the
+        /// block tracking object is garbage collected, the block tracking object's finalizer will automatically re-create and return
+        /// a new tracking object into the pool. This will only happen if there is a bug in the server, however it is necessary to avoid
+        /// leaving "dead zones" in the slab due to lost block tracking objects.
+        /// </summary>
+        /// <param name="block">The block to return. It must have been acquired by calling Lease on the same memory pool instance.</param>
+        internal void Return(MemoryPoolBlock block)
+        {
+#if BLOCK_LEASE_TRACKING
+            Debug.Assert(block.Pool == this, "Returned block was not leased from this pool");
+            Debug.Assert(block.IsLeased, $"Block being returned to pool twice: {block.Leaser}{Environment.NewLine}");
+            block.IsLeased = false;
+#endif
+
+            if (!_isDisposed)
+            {
+                _blocks.Enqueue(block);
+            }
+            else
+            {
+                GC.SuppressFinalize(block);
+            }
+        }
+
+        protected override void Dispose(bool disposing)
+        {
+            if (_isDisposed)
+            {
+                return;
+            }
+
+            lock (_disposeSync)
+            {
+                _isDisposed = true;
+
+                if (disposing)
+                {
+                    while (_slabs.TryPop(out MemoryPoolSlab slab))
+                    {
+                        // dispose managed state (managed objects).
+                        slab.Dispose();
+                    }
+                }
+
+                // Discard blocks in pool
+                while (_blocks.TryDequeue(out MemoryPoolBlock block))
+                {
+                    GC.SuppressFinalize(block);
+                }
+            }
+        }
+    }
+}

shared/Microsoft.Extensions.Buffers.Testing.Sources/BufferSegment.cs

@@ -0,0 +1,24 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+namespace System.Buffers
+{
+    internal class BufferSegment : ReadOnlySequenceSegment<byte>
+    {
+        public BufferSegment(Memory<byte> memory)
+        {
+            Memory = memory;
+        }
+
+        public BufferSegment Append(Memory<byte> memory)
+        {
+            var segment = new BufferSegment(memory)
+            {
+                RunningIndex = RunningIndex + Memory.Length
+            };
+            Next = segment;
+            return segment;
+        }
+    }
+}

shared/Microsoft.Extensions.Buffers.Testing.Sources/CustomMemoryForTest.cs

@@ -0,0 +1,45 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+namespace System.Buffers
+{
+    internal class CustomMemoryForTest<T> : IMemoryOwner<T>
+    {
+        private bool _disposed;
+        private T[] _array;
+        private readonly int _offset;
+        private readonly int _length;
+
+        public CustomMemoryForTest(T[] array): this(array, 0, array.Length)
+        {
+        }
+
+        public CustomMemoryForTest(T[] array, int offset, int length)
+        {
+            _array = array;
+            _offset = offset;
+            _length = length;
+        }
+
+        public Memory<T> Memory
+        {
+            get
+            {
+                if (_disposed)
+                    throw new ObjectDisposedException(nameof(CustomMemoryForTest<T>));
+                return new Memory<T>(_array, _offset, _length);
+            }
+        }
+
+        public void Dispose()
+        {
+            if (_disposed)
+                return;
+
+            _array = null;
+            _disposed = true;
+        }
+    }
+}
+

shared/Microsoft.Extensions.Buffers.Testing.Sources/ReadOnlySequenceFactory.cs

@@ -0,0 +1,148 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+using System.Collections.Generic;
+using System.Text;
+
+namespace System.Buffers
+{
+    internal abstract class ReadOnlySequenceFactory
+    {
+        public static ReadOnlySequenceFactory ArrayFactory { get; } = new ArrayTestSequenceFactory();
+        public static ReadOnlySequenceFactory MemoryFactory { get; } = new MemoryTestSequenceFactory();
+        public static ReadOnlySequenceFactory OwnedMemoryFactory { get; } = new OwnedMemoryTestSequenceFactory();
+        public static ReadOnlySequenceFactory SingleSegmentFactory { get; } = new SingleSegmentTestSequenceFactory();
+        public static ReadOnlySequenceFactory SegmentPerByteFactory { get; } = new BytePerSegmentTestSequenceFactory();
+
+        public abstract ReadOnlySequence<byte> CreateOfSize(int size);
+        public abstract ReadOnlySequence<byte> CreateWithContent(byte[] data);
+
+        public ReadOnlySequence<byte> CreateWithContent(string data)
+        {
+            return CreateWithContent(Encoding.ASCII.GetBytes(data));
+        }
+
+        internal class ArrayTestSequenceFactory : ReadOnlySequenceFactory
+        {
+            public override ReadOnlySequence<byte> CreateOfSize(int size)
+            {
+                return new ReadOnlySequence<byte>(new byte[size + 20], 10, size);
+            }
+
+            public override ReadOnlySequence<byte> CreateWithContent(byte[] data)
+            {
+                var startSegment = new byte[data.Length + 20];
+                Array.Copy(data, 0, startSegment, 10, data.Length);
+                return new ReadOnlySequence<byte>(startSegment, 10, data.Length);
+            }
+        }
+
+        internal class MemoryTestSequenceFactory : ReadOnlySequenceFactory
+        {
+            public override ReadOnlySequence<byte> CreateOfSize(int size)
+            {
+                return CreateWithContent(new byte[size]);
+            }
+
+            public override ReadOnlySequence<byte> CreateWithContent(byte[] data)
+            {
+                var startSegment = new byte[data.Length + 20];
+                Array.Copy(data, 0, startSegment, 10, data.Length);
+                return new ReadOnlySequence<byte>(new Memory<byte>(startSegment, 10, data.Length));
+            }
+        }
+
+        internal class OwnedMemoryTestSequenceFactory : ReadOnlySequenceFactory
+        {
+            public override ReadOnlySequence<byte> CreateOfSize(int size)
+            {
+                return CreateWithContent(new byte[size]);
+            }
+
+            public override ReadOnlySequence<byte> CreateWithContent(byte[] data)
+            {
+                var startSegment = new byte[data.Length + 20];
+                Array.Copy(data, 0, startSegment, 10, data.Length);
+                return new ReadOnlySequence<byte>(new CustomMemoryForTest<byte>(startSegment, 10, data.Length).Memory);
+            }
+        }
+
+        internal class SingleSegmentTestSequenceFactory : ReadOnlySequenceFactory
+        {
+            public override ReadOnlySequence<byte> CreateOfSize(int size)
+            {
+                return CreateWithContent(new byte[size]);
+            }
+
+            public override ReadOnlySequence<byte> CreateWithContent(byte[] data)
+            {
+                return CreateSegments(data);
+            }
+        }
+
+        internal class BytePerSegmentTestSequenceFactory : ReadOnlySequenceFactory
+        {
+            public override ReadOnlySequence<byte> CreateOfSize(int size)
+            {
+                return CreateWithContent(new byte[size]);
+            }
+
+            public override ReadOnlySequence<byte> CreateWithContent(byte[] data)
+            {
+                var segments = new List<byte[]>();
+
+                segments.Add(Array.Empty<byte>());
+                foreach (var b in data)
+                {
+                    segments.Add(new[] { b });
+                    segments.Add(Array.Empty<byte>());
+                }
+
+                return CreateSegments(segments.ToArray());
+            }
+        }
+
+        public static ReadOnlySequence<byte> CreateSegments(params byte[][] inputs)
+        {
+            if (inputs == null || inputs.Length == 0)
+            {
+                throw new InvalidOperationException();
+            }
+
+            int i = 0;
+
+            BufferSegment last = null;
+            BufferSegment first = null;
+
+            do
+            {
+                byte[] s = inputs[i];
+                int length = s.Length;
+                int dataOffset = length;
+                var chars = new byte[length * 2];
+
+                for (int j = 0; j < length; j++)
+                {
+                    chars[dataOffset + j] = s[j];
+                }
+
+                // Create a segment that has offset relative to the OwnedMemory and OwnedMemory itself has offset relative to array
+                var memory = new Memory<byte>(chars).Slice(length, length);
+
+                if (first == null)
+                {
+                    first = new BufferSegment(memory);
+                    last = first;
+                }
+                else
+                {
+                    last = last.Append(memory);
+                }
+                i++;
+            } while (i < inputs.Length);
+
+            return new ReadOnlySequence<byte>(first, 0, last, last.Memory.Length);
+        }
+    }
+}

src/Kestrel.Core/Internal/BufferReader.cs

@@ -0,0 +1,155 @@
+// Copyright (c) Microsoft. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license information.
+
+using System;
+using System.Buffers;
+using System.Runtime.CompilerServices;
+
+namespace System.Buffers
+{
+    internal ref struct BufferReader
+    {
+        private ReadOnlySpan<byte> _currentSpan;
+        private int _index;
+
+        private ReadOnlySequence<byte> _sequence;
+        private SequencePosition _currentSequencePosition;
+        private SequencePosition _nextSequencePosition;
+
+        private int _consumedBytes;
+        private bool _end;
+
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        public BufferReader(in ReadOnlySequence<byte> buffer)
+        {
+            _index = 0;
+            _consumedBytes = 0;
+            _sequence = buffer;
+            _currentSequencePosition = _sequence.Start;
+            _nextSequencePosition = _currentSequencePosition;
+
+            if (_sequence.TryGet(ref _nextSequencePosition, out var memory, true))
+            {
+                _end = false;
+                _currentSpan = memory.Span;
+                if (_currentSpan.Length == 0)
+                {
+                    // No space in first span, move to one with space
+                    MoveNext();
+                }
+            }
+            else
+            {
+                // No space in any spans and at end of sequence
+                _end = true;
+                _currentSpan = default;
+            }
+        }
+
+        public bool End => _end;
+
+        public int CurrentSegmentIndex => _index;
+
+        public SequencePosition Position => _sequence.GetPosition(_index, _currentSequencePosition);
+
+        public ReadOnlySpan<byte> CurrentSegment => _currentSpan;
+
+        public ReadOnlySpan<byte> UnreadSegment => _currentSpan.Slice(_index);
+
+        public int ConsumedBytes => _consumedBytes;
+
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        public int Peek()
+        {
+            if (_end)
+            {
+                return -1;
+            }
+            return _currentSpan[_index];
+        }
+
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        public int Read()
+        {
+            if (_end)
+            {
+                return -1;
+            }
+
+            var value = _currentSpan[_index];
+            _index++;
+            _consumedBytes++;
+
+            if (_index >= _currentSpan.Length)
+            {
+                MoveNext();
+            }
+
+            return value;
+        }
+
+        [MethodImpl(MethodImplOptions.NoInlining)]
+        private void MoveNext()
+        {
+            var previous = _nextSequencePosition;
+            while (_sequence.TryGet(ref _nextSequencePosition, out var memory, true))
+            {
+                _currentSequencePosition = previous;
+                _currentSpan = memory.Span;
+                _index = 0;
+                if (_currentSpan.Length > 0)
+                {
+                    return;
+                }
+            }
+            _end = true;
+        }
+
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        public void Advance(int byteCount)
+        {
+            if (!_end && byteCount > 0 && (_index + byteCount) < _currentSpan.Length)
+            {
+                _consumedBytes += byteCount;
+                _index += byteCount;
+            }
+            else
+            {
+                AdvanceNext(byteCount);
+            }
+        }
+
+        [MethodImpl(MethodImplOptions.NoInlining)]
+        private void AdvanceNext(int byteCount)
+        {
+            if (byteCount < 0)
+            {
+                BuffersThrowHelper.ThrowArgumentOutOfRangeException(BuffersThrowHelper.ExceptionArgument.length);
+            }
+
+            _consumedBytes += byteCount;
+
+            while (!_end && byteCount > 0)
+            {
+                if ((_index + byteCount) < _currentSpan.Length)
+                {
+                    _index += byteCount;
+                    byteCount = 0;
+                    break;
+                }
+
+                var remaining = (_currentSpan.Length - _index);
+
+                _index += remaining;
+                byteCount -= remaining;
+
+                MoveNext();
+            }
+
+            if (byteCount > 0)
+            {
+                BuffersThrowHelper.ThrowArgumentOutOfRangeException(BuffersThrowHelper.ExceptionArgument.length);
+            }
+        }
+    }
+}

src/Kestrel.Core/Internal/BufferWriter.cs

@@ -1,4 +1,3 @@
-
 // Copyright (c) .NET Foundation. All rights reserved.
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
@@ -6,16 +5,14 @@ using System.Runtime.CompilerServices;
 
 namespace System.Buffers
 {
-    // TODO: Once this is public, update the actual CountingBufferWriter in the Common repo,
-    // and go back to using that.
-    internal ref struct CountingBufferWriter<T> where T: IBufferWriter<byte>
+    internal ref struct BufferWriter<T> where T : IBufferWriter<byte>
     {
         private T _output;
         private Span<byte> _span;
         private int _buffered;
         private long _bytesCommitted;
 
-        public CountingBufferWriter(T output)
+        public BufferWriter(T output)
         {
             _buffered = 0;
             _bytesCommitted = 0;

src/Kestrel.Core/Internal/Http/ChunkWriter.cs

@@ -48,14 +48,14 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http
             return new ArraySegment<byte>(bytes, offset, 10 - offset);
         }
 
-        internal static int WriteBeginChunkBytes(ref CountingBufferWriter<PipeWriter> start, int dataCount)
+        internal static int WriteBeginChunkBytes(ref BufferWriter<PipeWriter> start, int dataCount)
         {
             var chunkSegment = BeginChunkBytes(dataCount);
             start.Write(new ReadOnlySpan<byte>(chunkSegment.Array, chunkSegment.Offset, chunkSegment.Count));
             return chunkSegment.Count;
         }
 
-        internal static void WriteEndChunkBytes(ref CountingBufferWriter<PipeWriter> start)
+        internal static void WriteEndChunkBytes(ref BufferWriter<PipeWriter> start)
         {
             start.Write(new ReadOnlySpan<byte>(_endChunkBytes.Array, _endChunkBytes.Offset, _endChunkBytes.Count));
         }

src/Kestrel.Core/Internal/Http/Http1OutputProducer.cs

@@ -117,7 +117,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http
                 }
 
                 var buffer = _pipeWriter;
-                var writer = new CountingBufferWriter<PipeWriter>(buffer);
+                var writer = new BufferWriter<PipeWriter>(buffer);
 
                 writer.Write(_bytesHttpVersion11);
                 var statusBytes = ReasonPhrases.ToStatusBytes(statusCode, reasonPhrase);
@@ -196,7 +196,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http
                     return Task.CompletedTask;
                 }
 
-                var writer = new CountingBufferWriter<PipeWriter>(_pipeWriter);
+                var writer = new BufferWriter<PipeWriter>(_pipeWriter);
                 if (buffer.Length > 0)
                 {
                     writer.Write(buffer);

src/Kestrel.Core/Internal/Http/HttpHeaders.Generated.cs

@@ -7765,7 +7765,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http
             return true;
         }
         
-        internal void CopyToFast(ref CountingBufferWriter<PipeWriter> output)
+        internal void CopyToFast(ref BufferWriter<PipeWriter> output)
         {
             var tempBits = _bits | (_contentLength.HasValue ? -9223372036854775808L : 0);
             

src/Kestrel.Core/Internal/Http/HttpProtocol.cs

@@ -936,7 +936,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http
             var bytesWritten = 0L;
             if (buffer.Length > 0)
             {
-                var writer = new CountingBufferWriter<PipeWriter>(writableBuffer);
+                var writer = new BufferWriter<PipeWriter>(writableBuffer);
 
                 ChunkWriter.WriteBeginChunkBytes(ref writer, buffer.Length);
                 writer.Write(buffer.Span);

src/Kestrel.Core/Internal/Http/HttpResponseHeaders.cs

@@ -27,7 +27,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http
             return GetEnumerator();
         }
 
-        internal void CopyTo(ref CountingBufferWriter<PipeWriter> buffer)
+        internal void CopyTo(ref BufferWriter<PipeWriter> buffer)
         {
             CopyToFast(ref buffer);
             if (MaybeUnknown != null)

src/Kestrel.Core/Internal/Http/PipelineExtensions.cs

@@ -40,7 +40,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http
             return result;
         }
 
-        internal static unsafe void WriteAsciiNoValidation(ref this CountingBufferWriter<PipeWriter> buffer, string data)
+        internal static unsafe void WriteAsciiNoValidation(ref this BufferWriter<PipeWriter> buffer, string data)
         {
             if (string.IsNullOrEmpty(data))
             {
@@ -69,7 +69,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http
         }
 
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        internal static unsafe void WriteNumeric(ref this CountingBufferWriter<PipeWriter> buffer, ulong number)
+        internal static unsafe void WriteNumeric(ref this BufferWriter<PipeWriter> buffer, ulong number)
         {
             const byte AsciiDigitStart = (byte)'0';
 
@@ -119,7 +119,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http
         }
 
         [MethodImpl(MethodImplOptions.NoInlining)]
-        private static void WriteNumericMultiWrite(ref this CountingBufferWriter<PipeWriter> buffer, ulong number)
+        private static void WriteNumericMultiWrite(ref this BufferWriter<PipeWriter> buffer, ulong number)
         {
             const byte AsciiDigitStart = (byte)'0';
 
@@ -140,7 +140,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http
         }
 
         [MethodImpl(MethodImplOptions.NoInlining)]
-        private unsafe static void WriteAsciiMultiWrite(ref this CountingBufferWriter<PipeWriter> buffer, string data)
+        private unsafe static void WriteAsciiMultiWrite(ref this BufferWriter<PipeWriter> buffer, string data)
         {
             var remaining = data.Length;
 

src/Kestrel.Core/Kestrel.Core.csproj

@@ -11,6 +11,10 @@
     <NoWarn>CS1591;$(NoWarn)</NoWarn>
   </PropertyGroup>
 
+  <ItemGroup>
+    <Compile Include="..\shared\ThrowHelper.cs" />
+  </ItemGroup>
+
   <ItemGroup>
     <PackageReference Include="Microsoft.AspNetCore.Certificates.Generation.Sources" PrivateAssets="All" Version="$(MicrosoftAspNetCoreCertificatesGenerationSourcesPackageVersion)" />
     <PackageReference Include="Microsoft.AspNetCore.Hosting.Abstractions" Version="$(MicrosoftAspNetCoreHostingAbstractionsPackageVersion)" />
@@ -21,8 +25,6 @@
     <PackageReference Include="Microsoft.Extensions.Options" Version="$(MicrosoftExtensionsOptionsPackageVersion)" />
     <PackageReference Include="System.Threading.Tasks.Extensions" Version="$(SystemThreadingTasksExtensionsPackageVersion)" />
     <PackageReference Include="System.Memory" Version="$(SystemMemoryPackageVersion)" />
-    <PackageReference Include="Microsoft.Extensions.Buffers.Sources" Version="$(MicrosoftExtensionsBuffersSourcesPackageVersion)" PrivateAssets="All" />
-    <PackageReference Include="Microsoft.Extensions.Buffers.MemoryPool.Sources" Version="$(MicrosoftExtensionsBuffersMemoryPoolSourcesPackageVersion)" PrivateAssets="All" />
     <PackageReference Include="System.Runtime.CompilerServices.Unsafe" Version="$(SystemRuntimeCompilerServicesUnsafePackageVersion)" />
     <PackageReference Include="System.Security.Cryptography.Cng" Version="$(SystemSecurityCryptographyCngPackageVersion)" />
     <PackageReference Include="System.Numerics.Vectors" Version="$(SystemNumericsVectorsPackageVersion)" />

src/Kestrel.Transport.Abstractions/Kestrel.Transport.Abstractions.csproj

@@ -13,11 +13,12 @@
   </PropertyGroup>
 
   <ItemGroup>
-    <ProjectReference Include="..\Connections.Abstractions\Connections.Abstractions.csproj" />
+    <Compile Include="..\shared\ThrowHelper.cs" />
+    <Compile Include="..\..\shared\Microsoft.Extensions.Buffers.MemoryPool.Sources\*.cs" />
   </ItemGroup>
+
   <ItemGroup>
-    <PackageReference Include="Microsoft.Extensions.Buffers.Sources" Version="$(MicrosoftExtensionsBuffersSourcesPackageVersion)" PrivateAssets="All" />
-    <PackageReference Include="Microsoft.Extensions.Buffers.MemoryPool.Sources" Version="$(MicrosoftExtensionsBuffersMemoryPoolSourcesPackageVersion)" PrivateAssets="All" />
+    <ProjectReference Include="..\Connections.Abstractions\Connections.Abstractions.csproj" />
   </ItemGroup>
 
 </Project>

src/Kestrel.Transport.Abstractions/Properties/AssemblyInfo.cs

@@ -0,0 +1,8 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System.Runtime.CompilerServices;
+
+[assembly: InternalsVisibleTo("Microsoft.AspNetCore.Server.Kestrel.Core.Tests, PublicKey=0024000004800000940000000602000000240000525341310004000001000100f33a29044fa9d740c9b3213a93e57c84b472c84e0b8a0e1ae48e67a9f8f6de9d5f7f3d52ac23e48ac51801f1dc950abe901da34d2a9e3baadb141a17c77ef3c565dd5ee5054b91cf63bb3c6ab83f72ab3aafe93d0fc3c2348b764fafb0b1c0733de51459aeab46580384bf9d74c4e28164b7cde247f891ba07891c9d872ad2bb")]
+[assembly: InternalsVisibleTo("Sockets.FunctionalTests, PublicKey=0024000004800000940000000602000000240000525341310004000001000100f33a29044fa9d740c9b3213a93e57c84b472c84e0b8a0e1ae48e67a9f8f6de9d5f7f3d52ac23e48ac51801f1dc950abe901da34d2a9e3baadb141a17c77ef3c565dd5ee5054b91cf63bb3c6ab83f72ab3aafe93d0fc3c2348b764fafb0b1c0733de51459aeab46580384bf9d74c4e28164b7cde247f891ba07891c9d872ad2bb")]
+[assembly: InternalsVisibleTo("Libuv.FunctionalTests, PublicKey=0024000004800000940000000602000000240000525341310004000001000100f33a29044fa9d740c9b3213a93e57c84b472c84e0b8a0e1ae48e67a9f8f6de9d5f7f3d52ac23e48ac51801f1dc950abe901da34d2a9e3baadb141a17c77ef3c565dd5ee5054b91cf63bb3c6ab83f72ab3aafe93d0fc3c2348b764fafb0b1c0733de51459aeab46580384bf9d74c4e28164b7cde247f891ba07891c9d872ad2bb")]

src/shared/ThrowHelper.cs

@@ -0,0 +1,34 @@
+// Copyright (c) Microsoft. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license information.
+
+using System.Diagnostics;
+using System.Runtime.CompilerServices;
+
+namespace System.Buffers
+{
+    internal class BuffersThrowHelper
+    {
+        public static void ThrowArgumentOutOfRangeException(ExceptionArgument argument)
+        {
+            throw GetArgumentOutOfRangeException(argument);
+        }
+
+        [MethodImpl(MethodImplOptions.NoInlining)]
+        private static ArgumentOutOfRangeException GetArgumentOutOfRangeException(ExceptionArgument argument)
+        {
+            return new ArgumentOutOfRangeException(GetArgumentName(argument));
+        }
+
+        private static string GetArgumentName(ExceptionArgument argument)
+        {
+            Debug.Assert(Enum.IsDefined(typeof(ExceptionArgument), argument), "The enum value is not defined, please check the ExceptionArgument Enum.");
+
+            return argument.ToString();
+        }
+
+        internal enum ExceptionArgument
+        {
+            length,
+        }
+    }
+}

test/Kestrel.Core.Tests/BufferReaderTests.cs

@@ -0,0 +1,300 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+using Xunit;
+
+namespace System.Buffers.Tests
+{
+    public abstract class ReadableBufferReaderFacts
+    {
+        public class Array : SingleSegment
+        {
+            public Array() : base(ReadOnlySequenceFactory.ArrayFactory) { }
+            internal Array(ReadOnlySequenceFactory factory) : base(factory) { }
+        }
+
+        public class OwnedMemory : SingleSegment
+        {
+            public OwnedMemory() : base(ReadOnlySequenceFactory.OwnedMemoryFactory) { }
+        }
+        public class Memory : SingleSegment
+        {
+            public Memory() : base(ReadOnlySequenceFactory.MemoryFactory) { }
+        }
+
+        public class SingleSegment : SegmentPerByte
+        {
+            public SingleSegment() : base(ReadOnlySequenceFactory.SingleSegmentFactory) { }
+            internal SingleSegment(ReadOnlySequenceFactory factory) : base(factory) { }
+
+            [Fact]
+            public void AdvanceSingleBufferSkipsBytes()
+            {
+                var reader = new BufferReader(Factory.CreateWithContent(new byte[] { 1, 2, 3, 4, 5 }));
+                reader.Advance(2);
+                Assert.Equal(2, reader.CurrentSegmentIndex);
+                Assert.Equal(3, reader.CurrentSegment[reader.CurrentSegmentIndex]);
+                Assert.Equal(3, reader.Peek());
+                reader.Advance(2);
+                Assert.Equal(5, reader.Peek());
+                Assert.Equal(4, reader.CurrentSegmentIndex);
+                Assert.Equal(5, reader.CurrentSegment[reader.CurrentSegmentIndex]);
+            }
+
+            [Fact]
+            public void TakeReturnsByteAndMoves()
+            {
+                var reader = new BufferReader(Factory.CreateWithContent(new byte[] { 1, 2 }));
+                Assert.Equal(0, reader.CurrentSegmentIndex);
+                Assert.Equal(1, reader.CurrentSegment[reader.CurrentSegmentIndex]);
+                Assert.Equal(1, reader.Read());
+                Assert.Equal(1, reader.CurrentSegmentIndex);
+                Assert.Equal(2, reader.CurrentSegment[reader.CurrentSegmentIndex]);
+                Assert.Equal(2, reader.Read());
+                Assert.Equal(-1, reader.Read());
+            }
+        }
+
+        public class SegmentPerByte : ReadableBufferReaderFacts
+        {
+            public SegmentPerByte() : base(ReadOnlySequenceFactory.SegmentPerByteFactory) { }
+            internal SegmentPerByte(ReadOnlySequenceFactory factory) : base(factory) { }
+        }
+
+        internal ReadOnlySequenceFactory Factory { get; }
+
+        internal ReadableBufferReaderFacts(ReadOnlySequenceFactory factory)
+        {
+            Factory = factory;
+        }
+
+        [Fact]
+        public void PeekReturnsByteWithoutMoving()
+        {
+            var reader = new BufferReader(Factory.CreateWithContent(new byte[] { 1, 2 }));
+            Assert.Equal(1, reader.Peek());
+            Assert.Equal(1, reader.Peek());
+        }
+
+        [Fact]
+        public void CursorIsCorrectAtEnd()
+        {
+            var reader = new BufferReader(Factory.CreateWithContent(new byte[] { 1, 2 }));
+            reader.Read();
+            reader.Read();
+            Assert.True(reader.End);
+        }
+
+        [Fact]
+        public void CursorIsCorrectWithEmptyLastBlock()
+        {
+            var first = new BufferSegment(new byte[] { 1, 2 });
+            var last = first.Append(new byte[4]);
+
+            var reader = new BufferReader(new ReadOnlySequence<byte>(first, 0, last, 0));
+            reader.Read();
+            reader.Read();
+            reader.Read();
+            Assert.Same(last, reader.Position.GetObject());
+            Assert.Equal(0, reader.Position.GetInteger());
+            Assert.True(reader.End);
+        }
+
+        [Fact]
+        public void PeekReturnsMinuOneByteInTheEnd()
+        {
+            var reader = new BufferReader(Factory.CreateWithContent(new byte[] { 1, 2 }));
+            Assert.Equal(1, reader.Read());
+            Assert.Equal(2, reader.Read());
+            Assert.Equal(-1, reader.Peek());
+        }
+
+        [Fact]
+        public void AdvanceToEndThenPeekReturnsMinusOne()
+        {
+            var reader = new BufferReader(Factory.CreateWithContent(new byte[] { 1, 2, 3, 4, 5 }));
+            reader.Advance(5);
+            Assert.True(reader.End);
+            Assert.Equal(-1, reader.Peek());
+        }
+
+        [Fact]
+        public void AdvancingPastLengthThrows()
+        {
+            var reader = new BufferReader(Factory.CreateWithContent(new byte[] { 1, 2, 3, 4, 5 }));
+            try
+            {
+                reader.Advance(6);
+                Assert.True(false);
+            }
+            catch (Exception ex)
+            {
+                Assert.True(ex is ArgumentOutOfRangeException);
+            }
+        }
+
+        [Fact]
+        public void CtorFindsFirstNonEmptySegment()
+        {
+            var buffer = Factory.CreateWithContent(new byte[] { 1 });
+            var reader = new BufferReader(buffer);
+
+            Assert.Equal(1, reader.Peek());
+        }
+
+        [Fact]
+        public void EmptySegmentsAreSkippedOnMoveNext()
+        {
+            var buffer = Factory.CreateWithContent(new byte[] { 1, 2 });
+            var reader = new BufferReader(buffer);
+
+            Assert.Equal(1, reader.Peek());
+            reader.Advance(1);
+            Assert.Equal(2, reader.Peek());
+        }
+
+        [Fact]
+        public void PeekGoesToEndIfAllEmptySegments()
+        {
+            var buffer = Factory.CreateOfSize(0);
+            var reader = new BufferReader(buffer);
+
+            Assert.Equal(-1, reader.Peek());
+            Assert.True(reader.End);
+        }
+
+        [Fact]
+        public void AdvanceTraversesSegments()
+        {
+            var buffer = Factory.CreateWithContent(new byte[] { 1, 2, 3 });
+            var reader = new BufferReader(buffer);
+
+            reader.Advance(2);
+            Assert.Equal(3, reader.CurrentSegment[reader.CurrentSegmentIndex]);
+            Assert.Equal(3, reader.Read());
+        }
+
+        [Fact]
+        public void AdvanceThrowsPastLengthMultipleSegments()
+        {
+            var buffer = Factory.CreateWithContent(new byte[] { 1, 2, 3 });
+            var reader = new BufferReader(buffer);
+
+            try
+            {
+                reader.Advance(4);
+                Assert.True(false);
+            }
+            catch (Exception ex)
+            {
+                Assert.True(ex is ArgumentOutOfRangeException);
+            }
+        }
+
+        [Fact]
+        public void TakeTraversesSegments()
+        {
+            var buffer = Factory.CreateWithContent(new byte[] { 1, 2, 3 });
+            var reader = new BufferReader(buffer);
+
+            Assert.Equal(1, reader.Read());
+            Assert.Equal(2, reader.Read());
+            Assert.Equal(3, reader.Read());
+            Assert.Equal(-1, reader.Read());
+        }
+
+        [Fact]
+        public void PeekTraversesSegments()
+        {
+            var buffer = Factory.CreateWithContent(new byte[] { 1, 2 });
+            var reader = new BufferReader(buffer);
+
+            Assert.Equal(1, reader.CurrentSegment[reader.CurrentSegmentIndex]);
+            Assert.Equal(1, reader.Read());
+
+            Assert.Equal(2, reader.CurrentSegment[reader.CurrentSegmentIndex]);
+            Assert.Equal(2, reader.Peek());
+            Assert.Equal(2, reader.Read());
+            Assert.Equal(-1, reader.Peek());
+            Assert.Equal(-1, reader.Read());
+        }
+
+        [Fact]
+        public void PeekWorkesWithEmptySegments()
+        {
+            var buffer = Factory.CreateWithContent(new byte[] { 1 });
+            var reader = new BufferReader(buffer);
+
+            Assert.Equal(0, reader.CurrentSegmentIndex);
+            Assert.Equal(1, reader.CurrentSegment.Length);
+            Assert.Equal(1, reader.Peek());
+            Assert.Equal(1, reader.Read());
+            Assert.Equal(-1, reader.Peek());
+            Assert.Equal(-1, reader.Read());
+        }
+
+        [Fact]
+        public void WorkesWithEmptyBuffer()
+        {
+            var reader = new BufferReader(Factory.CreateWithContent(new byte[] { }));
+
+            Assert.Equal(0, reader.CurrentSegmentIndex);
+            Assert.Equal(0, reader.CurrentSegment.Length);
+            Assert.Equal(-1, reader.Peek());
+            Assert.Equal(-1, reader.Read());
+        }
+
+        [Theory]
+        [InlineData(0, false)]
+        [InlineData(5, false)]
+        [InlineData(10, false)]
+        [InlineData(11, true)]
+        [InlineData(12, true)]
+        [InlineData(15, true)]
+        public void ReturnsCorrectCursor(int takes, bool end)
+        {
+            var readableBuffer = Factory.CreateWithContent(new byte[] { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 });
+            var reader = new BufferReader(readableBuffer);
+            for (int i = 0; i < takes; i++)
+            {
+                reader.Read();
+            }
+
+            var expected = end ? new byte[] { } : readableBuffer.Slice((long)takes).ToArray();
+            Assert.Equal(expected, readableBuffer.Slice(reader.Position).ToArray());
+        }
+
+        [Fact]
+        public void SlicingBufferReturnsCorrectCursor()
+        {
+            var buffer = Factory.CreateWithContent(new byte[] { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 });
+            var sliced = buffer.Slice(2L);
+
+            var reader = new BufferReader(sliced);
+            Assert.Equal(sliced.ToArray(), buffer.Slice(reader.Position).ToArray());
+            Assert.Equal(2, reader.Peek());
+            Assert.Equal(0, reader.CurrentSegmentIndex);
+        }
+
+        [Fact]
+        public void ReaderIndexIsCorrect()
+        {
+            var buffer = Factory.CreateWithContent(new byte[] { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 });
+            var reader = new BufferReader(buffer);
+
+            var counter = 1;
+            while (!reader.End)
+            {
+                var span = reader.CurrentSegment;
+                for (int i = reader.CurrentSegmentIndex; i < span.Length; i++)
+                {
+                    Assert.Equal(counter++, reader.CurrentSegment[i]);
+                }
+                reader.Advance(span.Length);
+            }
+            Assert.Equal(buffer.Length, reader.ConsumedBytes);
+        }
+    }
+
+}

test/Kestrel.Core.Tests/BufferWriterTests.cs

@@ -0,0 +1,228 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System.Buffers;
+using System.Collections.Generic;
+using System.Linq;
+using System.Threading.Tasks;
+using Xunit;
+
+namespace System.IO.Pipelines.Tests
+{
+    public class BufferWriterTests : IDisposable
+    {
+        protected Pipe Pipe;
+        public BufferWriterTests()
+        {
+            Pipe = new Pipe(new PipeOptions(useSynchronizationContext: false, pauseWriterThreshold: 0, resumeWriterThreshold: 0));
+        }
+
+        public void Dispose()
+        {
+            Pipe.Writer.Complete();
+            Pipe.Reader.Complete();
+        }
+
+        private byte[] Read()
+        {
+            Pipe.Writer.FlushAsync().GetAwaiter().GetResult();
+            Pipe.Writer.Complete();
+            ReadResult readResult = Pipe.Reader.ReadAsync().GetAwaiter().GetResult();
+            byte[] data = readResult.Buffer.ToArray();
+            Pipe.Reader.AdvanceTo(readResult.Buffer.End);
+            return data;
+        }
+
+        [Theory]
+        [InlineData(3, -1, 0)]
+        [InlineData(3, 0, -1)]
+        [InlineData(3, 0, 4)]
+        [InlineData(3, 4, 0)]
+        [InlineData(3, -1, -1)]
+        [InlineData(3, 4, 4)]
+        public void ThrowsForInvalidParameters(int arrayLength, int offset, int length)
+        {
+            BufferWriter<PipeWriter> writer = new BufferWriter<PipeWriter>(Pipe.Writer);
+            var array = new byte[arrayLength];
+            for (var i = 0; i < array.Length; i++)
+            {
+                array[i] = (byte)(i + 1);
+            }
+
+            writer.Write(new Span<byte>(array, 0, 0));
+            writer.Write(new Span<byte>(array, array.Length, 0));
+
+            try
+            {
+                writer.Write(new Span<byte>(array, offset, length));
+                Assert.True(false);
+            }
+            catch (Exception ex)
+            {
+                Assert.True(ex is ArgumentOutOfRangeException);
+            }
+
+            writer.Write(new Span<byte>(array, 0, array.Length));
+            writer.Commit();
+
+            Assert.Equal(array, Read());
+        }
+
+        [Theory]
+        [InlineData(0, 3)]
+        [InlineData(1, 2)]
+        [InlineData(2, 1)]
+        [InlineData(1, 1)]
+        public void CanWriteWithOffsetAndLength(int offset, int length)
+        {
+            BufferWriter<PipeWriter> writer = new BufferWriter<PipeWriter>(Pipe.Writer);
+            var array = new byte[] { 1, 2, 3 };
+
+            writer.Write(new Span<byte>(array, offset, length));
+
+            Assert.Equal(0, writer.BytesCommitted);
+
+            writer.Commit();
+
+            Assert.Equal(length, writer.BytesCommitted);
+            Assert.Equal(array.Skip(offset).Take(length).ToArray(), Read());
+            Assert.Equal(length, writer.BytesCommitted);
+        }
+
+        [Fact]
+        public void CanWriteEmpty()
+        {
+            BufferWriter<PipeWriter> writer = new BufferWriter<PipeWriter>(Pipe.Writer);
+            var array = new byte[] { };
+
+            writer.Write(array);
+            writer.Write(new Span<byte>(array, 0, array.Length));
+            writer.Commit();
+
+            Assert.Equal(0, writer.BytesCommitted);
+            Assert.Equal(array, Read());
+        }
+
+        [Fact]
+        public void CanWriteIntoHeadlessBuffer()
+        {
+            BufferWriter<PipeWriter> writer = new BufferWriter<PipeWriter>(Pipe.Writer);
+
+            writer.Write(new byte[] { 1, 2, 3 });
+            writer.Commit();
+
+            Assert.Equal(3, writer.BytesCommitted);
+            Assert.Equal(new byte[] { 1, 2, 3 }, Read());
+        }
+
+        [Fact]
+        public void CanWriteMultipleTimes()
+        {
+            BufferWriter<PipeWriter> writer = new BufferWriter<PipeWriter>(Pipe.Writer);
+
+            writer.Write(new byte[] { 1 });
+            writer.Write(new byte[] { 2 });
+            writer.Write(new byte[] { 3 });
+            writer.Commit();
+
+            Assert.Equal(3, writer.BytesCommitted);
+            Assert.Equal(new byte[] { 1, 2, 3 }, Read());
+        }
+
+        [Fact]
+        public void CanWriteOverTheBlockLength()
+        {
+            Memory<byte> memory = Pipe.Writer.GetMemory();
+            BufferWriter<PipeWriter> writer = new BufferWriter<PipeWriter>(Pipe.Writer);
+
+            IEnumerable<byte> source = Enumerable.Range(0, memory.Length).Select(i => (byte)i);
+            byte[] expectedBytes = source.Concat(source).Concat(source).ToArray();
+
+            writer.Write(expectedBytes);
+            writer.Commit();
+
+            Assert.Equal(expectedBytes.LongLength, writer.BytesCommitted);
+            Assert.Equal(expectedBytes, Read());
+        }
+
+        [Fact]
+        public void EnsureAllocatesSpan()
+        {
+            BufferWriter<PipeWriter> writer = new BufferWriter<PipeWriter>(Pipe.Writer);
+            writer.Ensure(10);
+            Assert.True(writer.Span.Length > 10);
+            Assert.Equal(0, writer.BytesCommitted);
+            Assert.Equal(new byte[] { }, Read());
+        }
+
+        [Fact]
+        public void ExposesSpan()
+        {
+            int initialLength = Pipe.Writer.GetMemory().Length;
+            BufferWriter<PipeWriter> writer = new BufferWriter<PipeWriter>(Pipe.Writer);
+            Assert.Equal(initialLength, writer.Span.Length);
+            Assert.Equal(new byte[] { }, Read());
+        }
+
+        [Fact]
+        public void SlicesSpanAndAdvancesAfterWrite()
+        {
+            int initialLength = Pipe.Writer.GetMemory().Length;
+
+            BufferWriter<PipeWriter> writer = new BufferWriter<PipeWriter>(Pipe.Writer);
+
+            writer.Write(new byte[] { 1, 2, 3 });
+            writer.Commit();
+
+            Assert.Equal(3, writer.BytesCommitted);
+            Assert.Equal(initialLength - 3, writer.Span.Length);
+            Assert.Equal(Pipe.Writer.GetMemory().Length, writer.Span.Length);
+            Assert.Equal(new byte[] { 1, 2, 3 }, Read());
+        }
+
+        [Fact]
+        public void BufferWriterCountsBytesCommitted()
+        {
+            BufferWriter<PipeWriter> writer = new BufferWriter<PipeWriter>(Pipe.Writer);
+
+            writer.Write(new byte[] { 1, 2, 3 });
+            Assert.Equal(0, writer.BytesCommitted);
+
+            writer.Commit();
+            Assert.Equal(3, writer.BytesCommitted);
+
+            writer.Ensure(10);
+            writer.Advance(10);
+            Assert.Equal(3, writer.BytesCommitted);
+
+            writer.Commit();
+            Assert.Equal(13, writer.BytesCommitted);
+
+            Pipe.Writer.FlushAsync().GetAwaiter().GetResult();
+            var readResult = Pipe.Reader.ReadAsync().GetAwaiter().GetResult();
+
+            // Consuming the buffer does not change BytesCommitted
+            Assert.Equal(13, readResult.Buffer.Length);
+            Assert.Equal(13, writer.BytesCommitted);
+        }
+
+        [Theory]
+        [InlineData(5)]
+        [InlineData(50)]
+        [InlineData(500)]
+        [InlineData(5000)]
+        [InlineData(50000)]
+        public void WriteLargeDataBinary(int length)
+        {
+            var data = new byte[length];
+            new Random(length).NextBytes(data);
+
+            BufferWriter<PipeWriter> writer = new BufferWriter<PipeWriter>(Pipe.Writer);
+            writer.Write(data);
+            writer.Commit();
+
+            Assert.Equal(length, writer.BytesCommitted);
+            Assert.Equal(data, Read());
+        }
+    }
+}

test/Kestrel.Core.Tests/DiagnosticMemoryPoolTests.cs

@@ -0,0 +1,228 @@
+// Copyright (c) Microsoft. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license information.
+
+using System;
+using System.Buffers;
+using System.Runtime.InteropServices;
+using System.Threading.Tasks;
+using Xunit;
+
+namespace Microsoft.Extensions.Internal.Test
+{
+    public class DiagnosticMemoryPoolTests: MemoryPoolTests
+    {
+        protected override MemoryPool<byte> CreatePool() => new DiagnosticMemoryPool(new SlabMemoryPool());
+
+        [Fact]
+        public void DoubleDisposeThrows()
+        {
+            var memoryPool = CreatePool();
+            memoryPool.Dispose();
+            var exception = Assert.Throws<InvalidOperationException>(() => memoryPool.Dispose());
+            Assert.Equal("Object is being disposed twice", exception.Message);
+        }
+
+        [Fact]
+        public void DisposeWithActiveBlocksThrows()
+        {
+            var memoryPool = CreatePool();
+            var block = memoryPool.Rent();
+            ExpectDisposeException(memoryPool);
+
+            var exception = Assert.Throws<InvalidOperationException>(() => block.Dispose());
+            Assert.Equal("Block is being returned to disposed pool", exception.Message);
+        }
+
+        [Fact]
+        public void DoubleBlockDisposeThrows()
+        {
+            var memoryPool = CreatePool();
+            var block = memoryPool.Rent();
+            block.Dispose();
+            var exception = Assert.Throws<InvalidOperationException>(() => block.Dispose());
+            Assert.Equal("Block is being disposed twice", exception.Message);
+
+            ExpectDisposeAggregateException(memoryPool, exception);
+        }
+
+        [Fact]
+        public void GetMemoryOfDisposedPoolThrows()
+        {
+            var memoryPool = CreatePool();
+            var block = memoryPool.Rent();
+
+            ExpectDisposeException(memoryPool);
+
+            var exception = Assert.Throws<InvalidOperationException>(() => block.Memory);
+            Assert.Equal("Block is backed by disposed slab", exception.Message);
+        }
+
+        [Fact]
+        public void GetMemoryPinOfDisposedPoolThrows()
+        {
+            var memoryPool = CreatePool();
+            var block = memoryPool.Rent();
+            var memory = block.Memory;
+
+            ExpectDisposeException(memoryPool);
+
+            var exception = Assert.Throws<InvalidOperationException>(() => memory.Pin());
+            Assert.Equal("Block is backed by disposed slab", exception.Message);
+        }
+
+        [Fact]
+        public void GetMemorySpanOfDisposedPoolThrows()
+        {
+            var memoryPool = CreatePool();
+            var block = memoryPool.Rent();
+            var memory = block.Memory;
+
+            ExpectDisposeException(memoryPool);
+
+            var threw = false;
+            try
+            {
+                _ = memory.Span;
+            }
+            catch (InvalidOperationException ode)
+            {
+                threw = true;
+                Assert.Equal("Block is backed by disposed slab", ode.Message);
+            }
+            Assert.True(threw);
+        }
+
+        [Fact]
+        public void GetMemoryTryGetArrayOfDisposedPoolThrows()
+        {
+            var memoryPool = CreatePool();
+            var block = memoryPool.Rent();
+            var memory = block.Memory;
+
+            ExpectDisposeException(memoryPool);
+
+            var exception = Assert.Throws<InvalidOperationException>(() => MemoryMarshal.TryGetArray<byte>(memory, out _));
+            Assert.Equal("Block is backed by disposed slab", exception.Message);
+        }
+
+        [Fact]
+        public void GetMemoryOfDisposedThrows()
+        {
+            var memoryPool = CreatePool();
+            var block = memoryPool.Rent();
+
+            block.Dispose();
+
+            var exception = Assert.Throws<ObjectDisposedException>(() => block.Memory);
+            Assert.Equal($"Cannot access a disposed object.{Environment.NewLine}Object name: 'MemoryPoolBlock'.", exception.Message);
+
+            ExpectDisposeAggregateException(memoryPool, exception);
+        }
+
+        [Fact]
+        public void GetMemoryPinOfDisposedThrows()
+        {
+            var memoryPool = CreatePool();
+            var block = memoryPool.Rent();
+            var memory = block.Memory;
+
+            block.Dispose();
+
+            var exception = Assert.Throws<ObjectDisposedException>(() => memory.Pin());
+            Assert.Equal($"Cannot access a disposed object.{Environment.NewLine}Object name: 'MemoryPoolBlock'.", exception.Message);
+
+            ExpectDisposeAggregateException(memoryPool, exception);
+        }
+
+        [Fact]
+        public void GetMemorySpanOfDisposedThrows()
+        {
+            var memoryPool = CreatePool();
+            var block = memoryPool.Rent();
+            var memory = block.Memory;
+
+            block.Dispose();
+
+            Exception exception = null;
+            try
+            {
+                _ = memory.Span;
+            }
+            catch (ObjectDisposedException ode)
+            {
+                exception = ode;
+                Assert.Equal($"Cannot access a disposed object.{Environment.NewLine}Object name: 'MemoryPoolBlock'.", ode.Message);
+            }
+            Assert.NotNull(exception);
+
+            ExpectDisposeAggregateException(memoryPool, exception);
+        }
+
+        [Fact]
+        public void GetMemoryTryGetArrayOfDisposedThrows()
+        {
+            var memoryPool = CreatePool();
+            var block = memoryPool.Rent();
+            var memory = block.Memory;
+
+            block.Dispose();
+
+            var exception = Assert.Throws<ObjectDisposedException>(() => MemoryMarshal.TryGetArray<byte>(memory, out _));
+            Assert.Equal($"Cannot access a disposed object.{Environment.NewLine}Object name: 'MemoryPoolBlock'.", exception.Message);
+
+            ExpectDisposeAggregateException(memoryPool, exception);
+        }
+
+        [Fact]
+        public async Task DoesNotThrowWithLateReturns()
+        {
+            var memoryPool = new DiagnosticMemoryPool(new SlabMemoryPool(), allowLateReturn: true);
+            var block = memoryPool.Rent();
+            memoryPool.Dispose();
+            block.Dispose();
+            await memoryPool.WhenAllBlocksReturnedAsync(TimeSpan.FromSeconds(5));
+        }
+
+        [Fact]
+        public async Task ThrowsOnAccessToLateBlocks()
+        {
+            var memoryPool = new DiagnosticMemoryPool(new SlabMemoryPool(), allowLateReturn: true);
+            var block = memoryPool.Rent();
+            memoryPool.Dispose();
+
+            var exception = Assert.Throws<InvalidOperationException>(() => block.Memory);
+            Assert.Equal("Block is backed by disposed slab", exception.Message);
+
+            block.Dispose();
+            var aggregateException = await Assert.ThrowsAsync<AggregateException>(async () => await memoryPool.WhenAllBlocksReturnedAsync(TimeSpan.FromSeconds(5)));
+
+            Assert.Equal(new Exception [] { exception }, aggregateException.InnerExceptions);
+        }
+
+        [Fact]
+        public void ExceptionsContainStackTraceWhenEnabled()
+        {
+            var memoryPool = new DiagnosticMemoryPool(new SlabMemoryPool(), rentTracking: true);
+            var block = memoryPool.Rent();
+
+            ExpectDisposeException(memoryPool);
+
+            var exception = Assert.Throws<InvalidOperationException>(() => block.Memory);
+            Assert.Contains("Block is backed by disposed slab", exception.Message);
+            Assert.Contains("ExceptionsContainStackTraceWhenEnabled", exception.Message);
+        }
+
+        private static void ExpectDisposeException(MemoryPool<byte> memoryPool)
+        {
+            var exception = Assert.Throws<InvalidOperationException>(() => memoryPool.Dispose());
+            Assert.Contains("Memory pool with active blocks is being disposed, 0 of 1 returned", exception.Message);
+        }
+
+        private static void ExpectDisposeAggregateException(MemoryPool<byte> memoryPool, params Exception[] inner)
+        {
+            var exception = Assert.Throws<AggregateException>(() => memoryPool.Dispose());
+
+            Assert.Equal(inner, exception.InnerExceptions);
+        }
+    }
+}

test/Kestrel.Core.Tests/Kestrel.Core.Tests.csproj

@@ -9,6 +9,7 @@
 
   <ItemGroup>
     <Compile Include="..\shared\**\*.cs" />
+    <Compile Include="..\..\shared\Microsoft.Extensions.Buffers.Testing.Sources\*.cs" />
     <Content Include="..\shared\TestCertificates\*.pfx" CopyToOutputDirectory="PreserveNewest" />
   </ItemGroup>
 
@@ -23,7 +24,6 @@
     <PackageReference Include="Microsoft.AspNetCore.Http" Version="$(MicrosoftAspNetCoreHttpPackageVersion)" />
     <PackageReference Include="System.Memory" Version="$(SystemMemoryPackageVersion)" />
     <PackageReference Include="System.Runtime.CompilerServices.Unsafe" Version="$(SystemRuntimeCompilerServicesUnsafePackageVersion)" />
-    <PackageReference Include="Microsoft.Extensions.Buffers.Testing.Sources" Version="$(MicrosoftExtensionsBuffersTestingSourcesPackageVersion)" />
   </ItemGroup>
 
 </Project>

test/Kestrel.Core.Tests/MemoryPoolTests.cs

@@ -0,0 +1,50 @@
+// Copyright (c) Microsoft. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license information.
+
+using System;
+using System.Buffers;
+using Xunit;
+
+namespace Microsoft.Extensions.Internal.Test
+{
+    public abstract class MemoryPoolTests
+    {
+        protected abstract MemoryPool<byte> CreatePool();
+
+        [Fact]
+        public void CanDisposeAfterCreation()
+        {
+            var memoryPool = CreatePool();
+            memoryPool.Dispose();
+        }
+
+        [Fact]
+        public void CanDisposeAfterReturningBlock()
+        {
+            var memoryPool = CreatePool();
+            var block = memoryPool.Rent();
+            block.Dispose();
+            memoryPool.Dispose();
+        }
+
+        [Fact]
+        public void CanDisposeAfterPinUnpinBlock()
+        {
+            var memoryPool = CreatePool();
+            var block = memoryPool.Rent();
+            block.Memory.Pin().Dispose();
+            block.Dispose();
+            memoryPool.Dispose();
+        }
+
+        [Fact]
+        public void LeasingFromDisposedPoolThrows()
+        {
+            var memoryPool = CreatePool();
+            memoryPool.Dispose();
+
+            var exception = Assert.Throws<ObjectDisposedException>(() => memoryPool.Rent());
+            Assert.Equal($"Cannot access a disposed object.{Environment.NewLine}Object name: 'MemoryPool'.", exception.Message);
+        }
+    }
+}

test/Kestrel.Core.Tests/PipelineExtensionTests.cs

@@ -38,7 +38,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
         public void WritesNumericToAscii(ulong number)
         {
             var writerBuffer = _pipe.Writer;
-            var writer = new CountingBufferWriter<PipeWriter>(writerBuffer);
+            var writer = new BufferWriter<PipeWriter>(writerBuffer);
             writer.WriteNumeric(number);
             writer.Commit();
             writerBuffer.FlushAsync().GetAwaiter().GetResult();
@@ -56,7 +56,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
         public void WritesNumericAcrossSpanBoundaries(int gapSize)
         {
             var writerBuffer = _pipe.Writer;
-            var writer = new CountingBufferWriter<PipeWriter>(writerBuffer);
+            var writer = new BufferWriter<PipeWriter>(writerBuffer);
             // almost fill up the first block
             var spacer = new byte[writer.Span.Length - gapSize];
             writer.Write(spacer);
@@ -87,7 +87,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
         public void EncodesAsAscii(string input, byte[] expected)
         {
             var pipeWriter = _pipe.Writer;
-            var writer = new CountingBufferWriter<PipeWriter>(pipeWriter);
+            var writer = new BufferWriter<PipeWriter>(pipeWriter);
             writer.WriteAsciiNoValidation(input);
             writer.Commit();
             pipeWriter.FlushAsync().GetAwaiter().GetResult();
@@ -117,7 +117,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
             // WriteAscii doesn't validate if characters are in the ASCII range
             // but it shouldn't produce more than one byte per character
             var writerBuffer = _pipe.Writer;
-            var writer = new CountingBufferWriter<PipeWriter>(writerBuffer);
+            var writer = new BufferWriter<PipeWriter>(writerBuffer);
             writer.WriteAsciiNoValidation(input);
             writer.Commit();
             writerBuffer.FlushAsync().GetAwaiter().GetResult();
@@ -131,7 +131,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
         {
             const byte maxAscii = 0x7f;
             var writerBuffer = _pipe.Writer;
-            var writer = new CountingBufferWriter<PipeWriter>(writerBuffer);
+            var writer = new BufferWriter<PipeWriter>(writerBuffer);
             for (var i = 0; i < maxAscii; i++)
             {
                 writer.WriteAsciiNoValidation(new string((char)i, 1));
@@ -161,7 +161,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
         {
             var testString = new string(' ', stringLength);
             var writerBuffer = _pipe.Writer;
-            var writer = new CountingBufferWriter<PipeWriter>(writerBuffer);
+            var writer = new BufferWriter<PipeWriter>(writerBuffer);
             // almost fill up the first block
             var spacer = new byte[writer.Span.Length - gapSize];
             writer.Write(spacer);

test/Kestrel.Core.Tests/SlabMemoryPoolTests.cs

@@ -0,0 +1,29 @@
+// Copyright (c) Microsoft. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license information.
+
+using System.Buffers;
+using Xunit;
+
+namespace Microsoft.Extensions.Internal.Test
+{
+    public  class SlabMemoryPoolTests: MemoryPoolTests
+    {
+        protected override MemoryPool<byte> CreatePool() => new SlabMemoryPool();
+
+        [Fact]
+        public void DoubleDisposeWorks()
+        {
+            var memoryPool = CreatePool();
+            memoryPool.Dispose();
+            memoryPool.Dispose();
+        }
+
+        [Fact]
+        public void DisposeWithActiveBlocksWorks()
+        {
+            var memoryPool = CreatePool();
+            var block = memoryPool.Rent();
+            memoryPool.Dispose();
+        }
+    }
+}

tools/CodeGenerator/KnownHeaders.cs

@@ -541,7 +541,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http
             return true;
         }}
         {(loop.ClassName == "HttpResponseHeaders" ? $@"
-        internal void CopyToFast(ref CountingBufferWriter<PipeWriter> output)
+        internal void CopyToFast(ref BufferWriter<PipeWriter> output)
         {{
             var tempBits = _bits | (_contentLength.HasValue ? {1L << 63}L : 0);
             {Each(loop.Headers.Where(header => header.Identifier != "ContentLength").OrderBy(h => !h.PrimaryHeader), header => $@"