async await where required

src/ImageSharp/Advanced/AdvancedImageExtensions.cs

@@ -4,8 +4,6 @@
 using System;
 using System.Collections.Generic;
 using System.IO;
-using System.Linq;
-using System.Runtime.InteropServices;
 using System.Text;
 using System.Threading.Tasks;
 using SixLabors.ImageSharp.Formats;
@@ -76,8 +74,8 @@ namespace SixLabors.ImageSharp.Advanced
         /// <param name="source">The source.</param>
         /// <param name="visitor">The visitor.</param>
         /// <returns>A  <see cref="Task"/> representing the asynchronous operation.</returns>
-        public static Task AcceptVisitorAsync(this Image source, IImageVisitorAsync visitor)
+        public static async Task AcceptVisitorAsync(this Image source, IImageVisitorAsync visitor)
-            => source.AcceptAsync(visitor);
+            => await source.AcceptAsync(visitor).ConfigureAwait(false);
 
         /// <summary>
         /// Gets the configuration for the image.

src/ImageSharp/Formats/Bmp/BmpEncoder.cs

@@ -42,11 +42,11 @@ namespace SixLabors.ImageSharp.Formats.Bmp
         }
 
         /// <inheritdoc/>
-        public Task EncodeAsync<TPixel>(Image<TPixel> image, Stream stream)
+        public async Task EncodeAsync<TPixel>(Image<TPixel> image, Stream stream)
             where TPixel : unmanaged, IPixel<TPixel>
         {
             var encoder = new BmpEncoderCore(this, image.GetMemoryAllocator());
-            return encoder.EncodeAsync(image, stream);
+            await encoder.EncodeAsync(image, stream).ConfigureAwait(false);
         }
     }
 }

src/ImageSharp/Formats/Gif/GifEncoder.cs

@@ -41,11 +41,11 @@ namespace SixLabors.ImageSharp.Formats.Gif
         }
 
         /// <inheritdoc/>
-        public Task EncodeAsync<TPixel>(Image<TPixel> image, Stream stream)
+        public async Task EncodeAsync<TPixel>(Image<TPixel> image, Stream stream)
             where TPixel : unmanaged, IPixel<TPixel>
         {
             var encoder = new GifEncoderCore(image.GetConfiguration(), this);
-            return encoder.EncodeAsync(image, stream);
+            await encoder.EncodeAsync(image, stream).ConfigureAwait(false);
         }
     }
 }

src/ImageSharp/Formats/Tga/TgaDecoder.cs

@@ -74,11 +74,11 @@ namespace SixLabors.ImageSharp.Formats.Tga
         }
 
         /// <inheritdoc/>
-        public Task<IImageInfo> IdentifyAsync(Configuration configuration, Stream stream)
+        public async Task<IImageInfo> IdentifyAsync(Configuration configuration, Stream stream)
         {
             Guard.NotNull(stream, nameof(stream));
 
-            return new TgaDecoderCore(configuration, this).IdentifyAsync(stream);
+            return await new TgaDecoderCore(configuration, this).IdentifyAsync(stream).ConfigureAwait(false);
         }
     }
 }

src/ImageSharp/Formats/Tga/TgaEncoder.cs

@@ -32,11 +32,11 @@ namespace SixLabors.ImageSharp.Formats.Tga
         }
 
         /// <inheritdoc/>
-        public Task EncodeAsync<TPixel>(Image<TPixel> image, Stream stream)
+        public async Task EncodeAsync<TPixel>(Image<TPixel> image, Stream stream)
             where TPixel : unmanaged, IPixel<TPixel>
         {
             var encoder = new TgaEncoderCore(this, image.GetMemoryAllocator());
-            return encoder.EncodeAsync(image, stream);
+            await encoder.EncodeAsync(image, stream).ConfigureAwait(false);
         }
     }
 }

src/ImageSharp/Image.Decode.cs

@@ -79,7 +79,7 @@ namespace SixLabors.ImageSharp
         /// <returns>The mime type or null if none found.</returns>
         private static Task<IImageFormat> InternalDetectFormatAsync(Stream stream, Configuration config)
         {
-            // we are going to cheat here because we know that by this point we have been wrapped in a
+            // We are going to cheat here because we know that by this point we have been wrapped in a
             // seekable stream then we are free to use sync APIs this is potentially brittle and may
             // need a better fix in the future.
             return Task.FromResult(InternalDetectFormat(stream, config));
@@ -184,7 +184,7 @@ namespace SixLabors.ImageSharp
                 return (null, null);
             }
 
-            var info = detector?.Identify(config, stream);
+            IImageInfo info = detector?.Identify(config, stream);
             return new FormattedImageInfo(info, format);
         }
 
@@ -203,7 +203,12 @@ namespace SixLabors.ImageSharp
                 return (null, null);
             }
 
-            var info = await detector?.IdentifyAsync(config, stream);
+            if (detector is null)
+            {
+                return (null, format);
+            }
+
+            IImageInfo info = await detector.IdentifyAsync(config, stream).ConfigureAwait(false);
             return new FormattedImageInfo(info, format);
         }
     }

src/ImageSharp/Image.FromStream.cs

@@ -57,8 +57,12 @@ namespace SixLabors.ImageSharp
         /// <exception cref="ArgumentNullException">The stream is null.</exception>
         /// <exception cref="NotSupportedException">The stream is not readable.</exception>
         /// <returns>The format type or null if none found.</returns>
-        public static Task<IImageFormat> DetectFormatAsync(Configuration configuration, Stream stream)
+        public static async Task<IImageFormat> DetectFormatAsync(Configuration configuration, Stream stream)
-            => WithSeekableStreamAsync(configuration, stream, s => InternalDetectFormatAsync(s, configuration));
+            => await WithSeekableStreamAsync(
+                configuration,
+                stream,
+                async s => await InternalDetectFormatAsync(s, configuration).ConfigureAwait(false))
+            .ConfigureAwait(false);
 
         /// <summary>
         /// Reads the raw image information from the specified stream without fully decoding it.
@@ -180,8 +184,12 @@ namespace SixLabors.ImageSharp
         /// <returns>
         /// The <see cref="FormattedImageInfo"/> with <see cref="FormattedImageInfo.ImageInfo"/> set to null if suitable info detector is not found.
         /// </returns>
-        public static Task<FormattedImageInfo> IdentifyWithFormatAsync(Configuration configuration, Stream stream)
+        public static async Task<FormattedImageInfo> IdentifyWithFormatAsync(Configuration configuration, Stream stream)
-            => WithSeekableStreamAsync(configuration, stream, s => InternalIdentityAsync(s, configuration ?? Configuration.Default));
+            => await WithSeekableStreamAsync(
+                configuration,
+                stream,
+                async s => await InternalIdentityAsync(s, configuration ?? Configuration.Default))
+            .ConfigureAwait(false);
 
         /// <summary>
         /// Decode a new instance of the <see cref="Image"/> class from the given stream.
@@ -330,7 +338,7 @@ namespace SixLabors.ImageSharp
         /// <returns>A new <see cref="Image"/>.</returns>>
         public static async Task<Image> LoadAsync(Configuration configuration, Stream stream)
         {
-            var fmt = await LoadWithFormatAsync(configuration, stream).ConfigureAwait(false);
+            FormattedImage fmt = await LoadWithFormatAsync(configuration, stream).ConfigureAwait(false);
             return fmt.Image;
         }
 
@@ -387,9 +395,9 @@ namespace SixLabors.ImageSharp
         /// <exception cref="InvalidImageContentException">Image contains invalid content.</exception>
         /// <typeparam name="TPixel">The pixel format.</typeparam>
         /// <returns>A <see cref="Task"/> representing the asynchronous operation.</returns>
-        public static Task<FormattedImage<TPixel>> LoadWithFormatAsync<TPixel>(Stream stream)
+        public static async Task<FormattedImage<TPixel>> LoadWithFormatAsync<TPixel>(Stream stream)
             where TPixel : unmanaged, IPixel<TPixel>
-            => LoadWithFormatAsync<TPixel>(Configuration.Default, stream);
+            => await LoadWithFormatAsync<TPixel>(Configuration.Default, stream).ConfigureAwait(false);
 
         /// <summary>
         /// Create a new instance of the <see cref="Image{TPixel}"/> class from the given stream.
@@ -417,9 +425,13 @@ namespace SixLabors.ImageSharp
         /// <exception cref="InvalidImageContentException">Image contains invalid content.</exception>
         /// <typeparam name="TPixel">The pixel format.</typeparam>
         /// <returns>A new <see cref="Image{TPixel}"/>.</returns>>
-        public static Task<Image<TPixel>> LoadAsync<TPixel>(Stream stream, IImageDecoder decoder)
+        public static async Task<Image<TPixel>> LoadAsync<TPixel>(Stream stream, IImageDecoder decoder)
             where TPixel : unmanaged, IPixel<TPixel>
-            => WithSeekableStreamAsync(Configuration.Default, stream, s => decoder.DecodeAsync<TPixel>(Configuration.Default, s));
+            => await WithSeekableStreamAsync(
+                Configuration.Default,
+                stream,
+                async s => await decoder.DecodeAsync<TPixel>(Configuration.Default, s).ConfigureAwait(false))
+            .ConfigureAwait(false);
 
         /// <summary>
         /// Create a new instance of the <see cref="Image{TPixel}"/> class from the given stream.
@@ -451,9 +463,13 @@ namespace SixLabors.ImageSharp
         /// <exception cref="InvalidImageContentException">Image contains invalid content.</exception>
         /// <typeparam name="TPixel">The pixel format.</typeparam>
         /// <returns>A new <see cref="Image{TPixel}"/>.</returns>>
-        public static Task<Image<TPixel>> LoadAsync<TPixel>(Configuration configuration, Stream stream, IImageDecoder decoder)
+        public static async Task<Image<TPixel>> LoadAsync<TPixel>(Configuration configuration, Stream stream, IImageDecoder decoder)
             where TPixel : unmanaged, IPixel<TPixel>
-            => WithSeekableStreamAsync(configuration, stream, s => decoder.DecodeAsync<TPixel>(configuration, s));
+            => await WithSeekableStreamAsync(
+                configuration,
+                stream,
+                async s => await decoder.DecodeAsync<TPixel>(configuration, s).ConfigureAwait(false))
+            .ConfigureAwait(false);
 
         /// <summary>
         /// Create a new instance of the <see cref="Image{TPixel}"/> class from the given stream.
@@ -520,7 +536,11 @@ namespace SixLabors.ImageSharp
         /// <returns>A new <see cref="Image{TPixel}"/>.</returns>
         public static async Task<FormattedImage> LoadWithFormatAsync(Configuration configuration, Stream stream)
         {
-            (Image img, IImageFormat format) data = await WithSeekableStreamAsync(configuration, stream, s => DecodeAsync(s, configuration));
+            (Image img, IImageFormat format) data = await WithSeekableStreamAsync(
+                    configuration,
+                    stream,
+                    async s => await DecodeAsync(s, configuration).ConfigureAwait(false))
+                .ConfigureAwait(false);
 
             if (data.img != null)
             {
@@ -553,7 +573,12 @@ namespace SixLabors.ImageSharp
         public static async Task<FormattedImage<TPixel>> LoadWithFormatAsync<TPixel>(Configuration configuration, Stream stream)
             where TPixel : unmanaged, IPixel<TPixel>
         {
-            (Image<TPixel> img, IImageFormat format) data = await WithSeekableStreamAsync(configuration, stream, s => DecodeAsync<TPixel>(s, configuration));
+            (Image<TPixel> img, IImageFormat format) data =
+                await WithSeekableStreamAsync(
+                    configuration,
+                    stream,
+                    async s => await DecodeAsync<TPixel>(s, configuration).ConfigureAwait(false))
+                .ConfigureAwait(false);
 
             if (data.img != null)
             {
@@ -646,6 +671,9 @@ namespace SixLabors.ImageSharp
             }
 
             // We want to be able to load images from things like HttpContext.Request.Body
+            // TODO: Should really find a nice way to use a pool for these.
+            // Investigate readonly version of the linked implementation.
+            // https://github.com/mgravell/Pipelines.Sockets.Unofficial/compare/mgravell:24482d4...mgravell:6740ea4
             using (var memoryStream = new MemoryStream())
             {
                 stream.CopyTo(memoryStream);
@@ -655,7 +683,10 @@ namespace SixLabors.ImageSharp
             }
         }
 
-        private static async Task<T> WithSeekableStreamAsync<T>(Configuration configuration, Stream stream, Func<Stream, Task<T>> action)
+        private static async Task<T> WithSeekableStreamAsync<T>(
+            Configuration configuration,
+            Stream stream,
+            Func<Stream, Task<T>> action)
         {
             Guard.NotNull(configuration, nameof(configuration));
             Guard.NotNull(stream, nameof(stream));
@@ -665,8 +696,9 @@ namespace SixLabors.ImageSharp
                 throw new NotSupportedException("Cannot read from the stream.");
             }
 
-            // to make sure we don't trigger anything with aspnetcore then we just need to make sure we are seekable and we make the copy using CopyToAsync
+            // To make sure we don't trigger anything with aspnetcore then we just need to make sure we are
-            // if the stream is seekable then we arn't using one of the aspnetcore wrapped streams that error on sync api calls and we can use it with out
+            // seekable and we make the copy using CopyToAsync if the stream is seekable then we arn't using
+            // one of the aspnetcore wrapped streams that error on sync api calls and we can use it without
             // having to further wrap
             if (stream.CanSeek)
             {
@@ -678,7 +710,8 @@ namespace SixLabors.ImageSharp
                 return await action(stream).ConfigureAwait(false);
             }
 
-            using (var memoryStream = new MemoryStream()) // should really find a nice way to use a pool for these!!
+            // TODO: See above comment.
+            using (var memoryStream = new MemoryStream())
             {
                 await stream.CopyToAsync(memoryStream).ConfigureAwait(false);
                 memoryStream.Position = 0;

src/ImageSharp/Image.cs

@@ -105,13 +105,13 @@ namespace SixLabors.ImageSharp
         /// <param name="encoder">The encoder to save the image with.</param>
         /// <exception cref="System.ArgumentNullException">Thrown if the stream or encoder is null.</exception>
         /// <returns>A <see cref="Task"/> representing the asynchronous operation.</returns>
-        public Task SaveAsync(Stream stream, IImageEncoder encoder)
+        public async Task SaveAsync(Stream stream, IImageEncoder encoder)
         {
             Guard.NotNull(stream, nameof(stream));
             Guard.NotNull(encoder, nameof(encoder));
             this.EnsureNotDisposed();
 
-            return this.AcceptVisitorAsync(new EncodeVisitor(encoder, stream));
+            await this.AcceptVisitorAsync(new EncodeVisitor(encoder, stream)).ConfigureAwait(false);
         }
 
         /// <summary>
@@ -177,16 +177,11 @@ namespace SixLabors.ImageSharp
             }
 
             public void Visit<TPixel>(Image<TPixel> image)
-                where TPixel : unmanaged, IPixel<TPixel>
+                where TPixel : unmanaged, IPixel<TPixel> => this.encoder.Encode(image, this.stream);
-            {
-                this.encoder.Encode(image, this.stream);
-            }
 
-            public Task VisitAsync<TPixel>(Image<TPixel> image)
+            public async Task VisitAsync<TPixel>(Image<TPixel> image)
                 where TPixel : unmanaged, IPixel<TPixel>
-            {
+                => await this.encoder.EncodeAsync(image, this.stream).ConfigureAwait(false);
-                return this.encoder.EncodeAsync(image, this.stream).ConfigureAwait(false);
-            }
         }
     }
 }