From 99fb1c4fb7e030fb0200711e6287b15fb5fb0ce5 Mon Sep 17 00:00:00 2001
From: pekspro <msn@pekspro.com>
Date: Sun, 5 Jul 2020 07:23:18 +0200
Subject: [PATCH 1/2] Adds DiscoverDecoderAsync.

---
 src/ImageSharp/Image.Decode.cs | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/src/ImageSharp/Image.Decode.cs b/src/ImageSharp/Image.Decode.cs
index 6b6dc6e21..1dededae4 100644
--- a/src/ImageSharp/Image.Decode.cs
+++ b/src/ImageSharp/Image.Decode.cs
@@ -101,6 +101,22 @@ namespace SixLabors.ImageSharp
                 : null;
         }
 
+        /// <summary>
+        /// By reading the header on the provided stream this calculates the images format.
+        /// </summary>
+        /// <param name="stream">The image stream to read the header from.</param>
+        /// <param name="config">The configuration.</param>
+        /// <param name="format">The IImageFormat.</param>
+        /// <returns>The image format or null if none found.</returns>
+        private static async Task<IImageDecoder> DiscoverDecoderAsync(Stream stream, Configuration config, out IImageFormat format)
+        {
+            format = await InternalDetectFormatAsync(stream, config).ConfigureAwait(false);
+
+            return format != null
+                ? config.ImageFormatsManager.FindDecoder(format)
+                : null;
+        }
+
         /// <summary>
         /// Decodes the image stream to the current image.
         /// </summary>

From b4c21c4299e14e48037c82c0160244ab4141d466 Mon Sep 17 00:00:00 2001
From: pekspro <msn@pekspro.com>
Date: Mon, 6 Jul 2020 19:15:32 +0200
Subject: [PATCH 2/2] Adds DiscoverDecoderAsync and starts using it.

---
 src/ImageSharp/Image.Decode.cs | 23 ++++++++++++++---------
 1 file changed, 14 insertions(+), 9 deletions(-)

diff --git a/src/ImageSharp/Image.Decode.cs b/src/ImageSharp/Image.Decode.cs
index 1dededae4..5330782f2 100644
--- a/src/ImageSharp/Image.Decode.cs
+++ b/src/ImageSharp/Image.Decode.cs
@@ -106,15 +106,16 @@ namespace SixLabors.ImageSharp
         /// </summary>
         /// <param name="stream">The image stream to read the header from.</param>
         /// <param name="config">The configuration.</param>
-        /// <param name="format">The IImageFormat.</param>
-        /// <returns>The image format or null if none found.</returns>
-        private static async Task<IImageDecoder> DiscoverDecoderAsync(Stream stream, Configuration config, out IImageFormat format)
+        /// <returns>The decoder and the image format or null if none found.</returns>
+        private static async Task<(IImageDecoder decoder, IImageFormat format)> DiscoverDecoderAsync(Stream stream, Configuration config)
         {
-            format = await InternalDetectFormatAsync(stream, config).ConfigureAwait(false);
+            IImageFormat format = await InternalDetectFormatAsync(stream, config).ConfigureAwait(false);
 
-            return format != null
+            IImageDecoder decoder = format != null
                 ? config.ImageFormatsManager.FindDecoder(format)
                 : null;
+
+            return (decoder, format);
         }
 
         /// <summary>
@@ -149,7 +150,7 @@ namespace SixLabors.ImageSharp
         private static async Task<(Image<TPixel> Image, IImageFormat Format)> DecodeAsync<TPixel>(Stream stream, Configuration config)
             where TPixel : unmanaged, IPixel<TPixel>
         {
-            IImageDecoder decoder = DiscoverDecoder(stream, config, out IImageFormat format);
+            (IImageDecoder decoder, IImageFormat format) = await DiscoverDecoderAsync(stream, config).ConfigureAwait(false);
             if (decoder is null)
             {
                 return (null, null);
@@ -173,7 +174,7 @@ namespace SixLabors.ImageSharp
 
         private static async Task<(Image Image, IImageFormat Format)> DecodeAsync(Stream stream, Configuration config)
         {
-            IImageDecoder decoder = DiscoverDecoder(stream, config, out IImageFormat format);
+            (IImageDecoder decoder, IImageFormat format) = await DiscoverDecoderAsync(stream, config).ConfigureAwait(false);
             if (decoder is null)
             {
                 return (null, null);
@@ -193,7 +194,9 @@ namespace SixLabors.ImageSharp
         /// </returns>
         private static (IImageInfo ImageInfo, IImageFormat Format) InternalIdentity(Stream stream, Configuration config)
         {
-            if (!(DiscoverDecoder(stream, config, out IImageFormat format) is IImageInfoDetector detector))
+            IImageDecoder decoder = DiscoverDecoder(stream, config, out IImageFormat format);
+
+            if (!(decoder is IImageInfoDetector detector))
             {
                 return (null, null);
             }
@@ -213,7 +216,9 @@ namespace SixLabors.ImageSharp
         /// is not found.</returns>
         private static async Task<(IImageInfo ImageInfo, IImageFormat Format)> InternalIdentityAsync(Stream stream, Configuration config)
         {
-            if (!(DiscoverDecoder(stream, config, out IImageFormat format) is IImageInfoDetector detector))
+            (IImageDecoder decoder, IImageFormat format) = await DiscoverDecoderAsync(stream, config).ConfigureAwait(false);
+
+            if (!(decoder is IImageInfoDetector detector))
             {
                 return (null, null);
             }