Improvements around streams

* Use ArrayPool instead of allocating new buffers each time
* Remove NetworkStream copy
* Remove some dead code

1 files changed, 136 insertions, 90 deletions

diff --git a/Emby.Server.Implementations/IO/StreamHelper.cs b/Emby.Server.Implementations/IO/StreamHelper.cs
index 09cf4d4a3..d02cd84a0 100644
--- a/Emby.Server.Implementations/IO/StreamHelper.cs
+++ b/Emby.Server.Implementations/IO/StreamHelper.cs
@@ -1,4 +1,5 @@
 using System;
+using System.Buffers;
 using System.IO;
 using System.Threading;
 using System.Threading.Tasks;
@@ -8,168 +9,213 @@ namespace Emby.Server.Implementations.IO
 {
     public class StreamHelper : IStreamHelper
     {
+        private const int StreamCopyToBufferSize = 81920;
+
         public async Task CopyToAsync(Stream source, Stream destination, int bufferSize, Action onStarted, CancellationToken cancellationToken)
         {
-            byte[] buffer = new byte[bufferSize];
-            int read;
-            while ((read = source.Read(buffer, 0, buffer.Length)) != 0)
+            byte[] buffer = ArrayPool<byte>.Shared.Rent(bufferSize);
+            try
             {
-                cancellationToken.ThrowIfCancellationRequested();
+                int read;
+                while ((read = await source.ReadAsync(buffer, 0, buffer.Length).ConfigureAwait(false)) != 0)
+                {
+                    cancellationToken.ThrowIfCancellationRequested();
 
-                await destination.WriteAsync(buffer, 0, read).ConfigureAwait(false);
+                    await destination.WriteAsync(buffer, 0, read).ConfigureAwait(false);
 
-                if (onStarted != null)
-                {
-                    onStarted();
-                    onStarted = null;
+                    if (onStarted != null)
+                    {
+                        onStarted();
+                        onStarted = null;
+                    }
                 }
             }
+            finally
+            {
+                ArrayPool<byte>.Shared.Return(buffer);
+            }
         }
 
         public async Task CopyToAsync(Stream source, Stream destination, int bufferSize, int emptyReadLimit, CancellationToken cancellationToken)
         {
-            byte[] buffer = new byte[bufferSize];
-
-            if (emptyReadLimit <= 0)
+            byte[] buffer = ArrayPool<byte>.Shared.Rent(bufferSize);
+            try
             {
-                int read;
-                while ((read = source.Read(buffer, 0, buffer.Length)) != 0)
+                if (emptyReadLimit <= 0)
                 {
-                    cancellationToken.ThrowIfCancellationRequested();
+                    int read;
+                    while ((read = await source.ReadAsync(buffer, 0, buffer.Length).ConfigureAwait(false)) != 0)
+                    {
+                        cancellationToken.ThrowIfCancellationRequested();
 
-                    await destination.WriteAsync(buffer, 0, read).ConfigureAwait(false);
-                }
+                        await destination.WriteAsync(buffer, 0, read).ConfigureAwait(false);
+                    }
 
-                return;
-            }
+                    return;
+                }
 
-            var eofCount = 0;
+                var eofCount = 0;
 
-            while (eofCount < emptyReadLimit)
-            {
-                cancellationToken.ThrowIfCancellationRequested();
+                while (eofCount < emptyReadLimit)
+                {
+                    cancellationToken.ThrowIfCancellationRequested();
 
-                var bytesRead = source.Read(buffer, 0, buffer.Length);
+                    var bytesRead = await source.ReadAsync(buffer, 0, buffer.Length).ConfigureAwait(false);
 
-                if (bytesRead == 0)
-                {
-                    eofCount++;
-                    await Task.Delay(50, cancellationToken).ConfigureAwait(false);
-                }
-                else
-                {
-                    eofCount = 0;
+                    if (bytesRead == 0)
+                    {
+                        eofCount++;
+                        await Task.Delay(50, cancellationToken).ConfigureAwait(false);
+                    }
+                    else
+                    {
+                        eofCount = 0;
 
-                    await destination.WriteAsync(buffer, 0, bytesRead).ConfigureAwait(false);
+                        await destination.WriteAsync(buffer, 0, bytesRead).ConfigureAwait(false);
+                    }
                 }
             }
+            finally
+            {
+                ArrayPool<byte>.Shared.Return(buffer);
+            }
         }
 
-        const int StreamCopyToBufferSize = 81920;
         public async Task<int> CopyToAsync(Stream source, Stream destination, CancellationToken cancellationToken)
         {
-            var array = new byte[StreamCopyToBufferSize];
-            int bytesRead;
-            int totalBytesRead = 0;
-
-            while ((bytesRead = await source.ReadAsync(array, 0, array.Length, cancellationToken).ConfigureAwait(false)) != 0)
+            byte[] buffer = ArrayPool<byte>.Shared.Rent(StreamCopyToBufferSize);
+            try
             {
-                var bytesToWrite = bytesRead;
+                int totalBytesRead = 0;
 
-                if (bytesToWrite > 0)
+                int bytesRead;
+                while ((bytesRead = await source.ReadAsync(buffer, 0, buffer.Length, cancellationToken).ConfigureAwait(false)) != 0)
                 {
-                    await destination.WriteAsync(array, 0, Convert.ToInt32(bytesToWrite), cancellationToken).ConfigureAwait(false);
+                    var bytesToWrite = bytesRead;
 
-                    totalBytesRead += bytesRead;
+                    if (bytesToWrite > 0)
+                    {
+                        await destination.WriteAsync(buffer, 0, Convert.ToInt32(bytesToWrite), cancellationToken).ConfigureAwait(false);
+
+                        totalBytesRead += bytesRead;
+                    }
                 }
-            }
 
-            return totalBytesRead;
+                return totalBytesRead;
+            }
+            finally
+            {
+                ArrayPool<byte>.Shared.Return(buffer);
+            }
         }
 
         public async Task<int> CopyToAsyncWithSyncRead(Stream source, Stream destination, CancellationToken cancellationToken)
         {
-            var array = new byte[StreamCopyToBufferSize];
-            int bytesRead;
-            int totalBytesRead = 0;
-
-            while ((bytesRead = source.Read(array, 0, array.Length)) != 0)
+            byte[] buffer = ArrayPool<byte>.Shared.Rent(StreamCopyToBufferSize);
+            try
             {
-                var bytesToWrite = bytesRead;
+                int bytesRead;
+                int totalBytesRead = 0;
 
-                if (bytesToWrite > 0)
+                while ((bytesRead = source.Read(buffer, 0, buffer.Length)) != 0)
                 {
-                    await destination.WriteAsync(array, 0, Convert.ToInt32(bytesToWrite), cancellationToken).ConfigureAwait(false);
+                    var bytesToWrite = bytesRead;
 
-                    totalBytesRead += bytesRead;
+                    if (bytesToWrite > 0)
+                    {
+                        await destination.WriteAsync(buffer, 0, Convert.ToInt32(bytesToWrite), cancellationToken).ConfigureAwait(false);
+
+                        totalBytesRead += bytesRead;
+                    }
                 }
-            }
 
-            return totalBytesRead;
+                return totalBytesRead;
+            }
+            finally
+            {
+                ArrayPool<byte>.Shared.Return(buffer);
+            }
         }
 
         public async Task CopyToAsyncWithSyncRead(Stream source, Stream destination, long copyLength, CancellationToken cancellationToken)
         {
-            var array = new byte[StreamCopyToBufferSize];
-            int bytesRead;
-
-            while ((bytesRead = source.Read(array, 0, array.Length)) != 0)
+            byte[] buffer = ArrayPool<byte>.Shared.Rent(StreamCopyToBufferSize);
+            try
             {
-                var bytesToWrite = Math.Min(bytesRead, copyLength);
+                int bytesRead;
 
-                if (bytesToWrite > 0)
+                while ((bytesRead = source.Read(buffer, 0, buffer.Length)) != 0)
                 {
-                    await destination.WriteAsync(array, 0, Convert.ToInt32(bytesToWrite), cancellationToken).ConfigureAwait(false);
-                }
+                    var bytesToWrite = Math.Min(bytesRead, copyLength);
 
-                copyLength -= bytesToWrite;
+                    if (bytesToWrite > 0)
+                    {
+                        await destination.WriteAsync(buffer, 0, Convert.ToInt32(bytesToWrite), cancellationToken).ConfigureAwait(false);
+                    }
 
-                if (copyLength <= 0)
-                {
-                    break;
+                    copyLength -= bytesToWrite;
+
+                    if (copyLength <= 0)
+                    {
+                        break;
+                    }
                 }
             }
+            finally
+            {
+                ArrayPool<byte>.Shared.Return(buffer);
+            }
         }
 
         public async Task CopyToAsync(Stream source, Stream destination, long copyLength, CancellationToken cancellationToken)
         {
-            var array = new byte[StreamCopyToBufferSize];
-            int bytesRead;
-
-            while ((bytesRead = await source.ReadAsync(array, 0, array.Length, cancellationToken).ConfigureAwait(false)) != 0)
+            byte[] buffer = ArrayPool<byte>.Shared.Rent(StreamCopyToBufferSize);
+            try
             {
-                var bytesToWrite = Math.Min(bytesRead, copyLength);
+                int bytesRead;
 
-                if (bytesToWrite > 0)
+                while ((bytesRead = await source.ReadAsync(buffer, 0, buffer.Length, cancellationToken).ConfigureAwait(false)) != 0)
                 {
-                    await destination.WriteAsync(array, 0, Convert.ToInt32(bytesToWrite), cancellationToken).ConfigureAwait(false);
-                }
+                    var bytesToWrite = Math.Min(bytesRead, copyLength);
 
-                copyLength -= bytesToWrite;
+                    if (bytesToWrite > 0)
+                    {
+                        await destination.WriteAsync(buffer, 0, Convert.ToInt32(bytesToWrite), cancellationToken).ConfigureAwait(false);
+                    }
 
-                if (copyLength <= 0)
-                {
-                    break;
+                    copyLength -= bytesToWrite;
+
+                    if (copyLength <= 0)
+                    {
+                        break;
+                    }
                 }
             }
+            finally
+            {
+                ArrayPool<byte>.Shared.Return(buffer);
+            }
         }
 
         public async Task CopyUntilCancelled(Stream source, Stream target, int bufferSize, CancellationToken cancellationToken)
         {
-            byte[] buffer = new byte[bufferSize];
-
-            while (!cancellationToken.IsCancellationRequested)
+            byte[] buffer = ArrayPool<byte>.Shared.Rent(bufferSize);
+            try
             {
-                var bytesRead = await CopyToAsyncInternal(source, target, buffer, cancellationToken).ConfigureAwait(false);
-
-                //var position = fs.Position;
-                //_logger.LogDebug("Streamed {0} bytes to position {1} from file {2}", bytesRead, position, path);
-
-                if (bytesRead == 0)
+                while (!cancellationToken.IsCancellationRequested)
                 {
-                    await Task.Delay(100).ConfigureAwait(false);
+                    var bytesRead = await CopyToAsyncInternal(source, target, buffer, cancellationToken).ConfigureAwait(false);
+
+                    if (bytesRead == 0)
+                    {
+                        await Task.Delay(100).ConfigureAwait(false);
+                    }
                 }
             }
+            finally
+            {
+                ArrayPool<byte>.Shared.Return(buffer);
+            }
         }
 
         private static async Task<int> CopyToAsyncInternal(Stream source, Stream destination, byte[] buffer, CancellationToken cancellationToken)