Add IFileSystem

src/ImageSharp/Configuration.cs

@@ -12,6 +12,7 @@ namespace ImageSharp
     using System.Threading.Tasks;
 
     using Formats;
+    using ImageSharp.IO;
 
     /// <summary>
     /// Provides initialization code which allows extending the library.
@@ -53,6 +54,13 @@ namespace ImageSharp
         /// </summary>
         internal int MaxHeaderSize { get; private set; }
 
+#if !NETSTANDARD1_1
+        /// <summary>
+        /// Helper for accessing the local file system.
+        /// </summary>
+        internal IFileSystem FileSystem { get; set; } = new LocalFileSystem();
+#endif
+
         /// <summary>
         /// Adds a new <see cref="IImageFormat"/> to the collection of supported image formats.
         /// </summary>

src/ImageSharp/IO/IFileSystem.cs

@@ -0,0 +1,31 @@
+// <copyright file="Endianness.cs" company="James Jackson-South">
+// Copyright (c) James Jackson-South and contributors.
+// Licensed under the Apache License, Version 2.0.
+// </copyright>
+
+using System.IO;
+
+namespace ImageSharp.IO
+{
+#if !NETSTANDARD1_1
+    /// <summary>
+    /// A simple interface representing the filesystem.
+    /// </summary>
+    public interface IFileSystem
+    {
+        /// <summary>
+        /// Returns a readable stream as defined by the path.
+        /// </summary>
+        /// <param name="path">Path to the file to open.</param>
+        /// <returns>A stream representing the file to open.</returns>
+        Stream OpenRead(string path);
+
+        /// <summary>
+        /// Creates or opens a file and returns it as a writeable stream as defined by the path.
+        /// </summary>
+        /// <param name="path">Path to the file to open.</param>
+        /// <returns>A stream representing the file to open.</returns>
+        Stream OpenWrite(string path);
+    }
+#endif
+}

src/ImageSharp/IO/LocalFileSystem.cs

@@ -0,0 +1,27 @@
+using System;
+using System.Collections.Generic;
+using System.IO;
+using System.Text;
+
+namespace ImageSharp.IO
+{
+#if !NETSTANDARD1_1
+    /// <summary>
+    /// A wrapper around the local File apis.
+    /// </summary>
+    public class LocalFileSystem : IFileSystem
+    {
+        /// <inheritdoc/>
+        public Stream OpenRead(string path)
+        {
+            return File.OpenRead(path);
+        }
+
+        /// <inheritdoc/>
+        public Stream OpenWrite(string path)
+        {
+            return File.OpenWrite(path);
+        }
+    }
+#endif
+}

src/ImageSharp/Image/Image{TColor}.cs

@@ -168,7 +168,7 @@ namespace ImageSharp
             : base(configuration)
         {
             Guard.NotNull(filePath, nameof(filePath));
-            using (FileStream fs = File.OpenRead(filePath))
+            using (Stream fs = File.OpenRead(filePath))
             {
                 this.Load(fs, options);
             }
@@ -349,7 +349,7 @@ namespace ImageSharp
         public Image<TColor> Save(Stream stream, IEncoderOptions options)
         {
             Guard.NotNull(stream, nameof(stream));
-            this.CurrentImageFormat.Encoder.Encode(this, stream, options);
+            this.SaveInternal(stream, this.CurrentImageFormat?.Encoder, options);
             return this;
         }
 
@@ -373,9 +373,10 @@ namespace ImageSharp
         /// <returns>The <see cref="Image{TColor}"/></returns>
         public Image<TColor> Save(Stream stream, IImageFormat format, IEncoderOptions options)
         {
-            Guard.NotNull(stream, nameof(stream));
             Guard.NotNull(format, nameof(format));
-            format.Encoder.Encode(this, stream, options);
+
+            this.SaveInternal(stream, format.Encoder, options);
+
             return this;
         }
 
@@ -405,15 +406,7 @@ namespace ImageSharp
         /// </returns>
         public Image<TColor> Save(Stream stream, IImageEncoder encoder, IEncoderOptions options)
         {
-            Guard.NotNull(stream, nameof(stream));
+            this.SaveInternal(stream, encoder, options);
-            Guard.NotNull(encoder, nameof(encoder));
-            encoder.Encode(this, stream, options);
-
-            // Reset to the start of the stream.
-            if (stream.CanSeek)
-            {
-                stream.Position = 0;
-            }
 
             return this;
         }
@@ -569,6 +562,29 @@ namespace ImageSharp
             return target;
         }
 
+        /// <summary>
+        /// Internally saves the image to the given stream using the given image encoder and options.
+        /// Can be used by overridden by tests to verify save opperations.
+        /// </summary>
+        /// <param name="stream">The stream to save the image to.</param>
+        /// <param name="encoder">The encoder to save the image with.</param>
+        /// <param name="options">The options for the encoder.</param>
+        /// <exception cref="System.ArgumentNullException">Thrown if the stream or encoder is null.</exception>
+        internal virtual void SaveInternal(Stream stream, IImageEncoder encoder, IEncoderOptions options)
+        {
+            Guard.NotNull(stream, nameof(stream));
+            Guard.NotNull(encoder, nameof(encoder));
+
+            long startOfStream = stream.Position;
+            encoder.Encode(this, stream, options);
+
+            // Reset to the start of the stream.
+            if (stream.CanSeek)
+            {
+                stream.Position = startOfStream;
+            }
+        }
+
         /// <summary>
         /// Creates a new <see cref="ImageFrame{TColor}"/> from this instance
         /// </summary>

tests/ImageSharp.Tests/ConfigurationTests.cs

@@ -10,7 +10,7 @@ namespace ImageSharp.Tests
     using System.Linq;
 
     using ImageSharp.Formats;
-
+    using ImageSharp.IO;
     using Xunit;
 
     /// <summary>
@@ -18,6 +18,16 @@ namespace ImageSharp.Tests
     /// </summary>
     public class ConfigurationTests
     {
+        [Fact]
+        public void DefaultsToLocalFileSystem()
+        {
+            var configuration = Configuration.CreateDefaultInstance();
+
+            ImageSharp.IO.IFileSystem fs = configuration.FileSystem;
+
+            Assert.IsType<LocalFileSystem>(fs);
+        }
+
         [Fact]
         public void IfAutoloadWellknwonFormatesIsTrueAllFormateAreLoaded()
         {

tests/ImageSharp.Tests/IO/LocalFileSystem.cs

@@ -0,0 +1,53 @@
+// <copyright file="LittleEndianBitConverterTests.cs" company="James Jackson-South">
+// Copyright (c) James Jackson-South and contributors.
+// Licensed under the Apache License, Version 2.0.
+// </copyright>
+
+namespace ImageSharp.Tests.IO
+{
+    using System;
+    using System.IO;
+    using ImageSharp.IO;
+
+    using Xunit;
+
+    public class LocalFileSystemTests
+    {
+        [Fact]
+        public void OpenRead()
+        {
+            string path = Path.GetTempFileName();
+            string testData = Guid.NewGuid().ToString();
+            File.WriteAllText(path, testData);
+
+            LocalFileSystem fs = new LocalFileSystem();
+
+            using (var r = new StreamReader(fs.OpenRead(path)))
+            {
+                string data = r.ReadToEnd();
+
+                Assert.Equal(testData, data);
+            }
+
+            File.Delete(path);
+        }
+
+        [Fact]
+        public void OpenWrite()
+        {
+            string path = Path.GetTempFileName();
+            string testData = Guid.NewGuid().ToString();
+            LocalFileSystem fs = new LocalFileSystem();
+
+            using (var r = new StreamWriter(fs.OpenWrite(path)))
+            {
+                r.Write(testData);
+            }
+
+            string data = File.ReadAllText(path);
+            Assert.Equal(testData, data);
+
+            File.Delete(path);
+        }
+    }
+}

tests/ImageSharp.Tests/Image/ImageSaveTests.cs

@@ -0,0 +1,48 @@
+// <copyright file="PixelAccessorTests.cs" company="James Jackson-South">
+// Copyright (c) James Jackson-South and contributors.
+// Licensed under the Apache License, Version 2.0.
+// </copyright>
+
+namespace ImageSharp.Tests
+{
+    using System;
+    using System.IO;
+    using System.Linq;
+    using ImageSharp.Formats;
+    using ImageSharp.IO;
+    using Moq;
+    using Xunit;
+
+    /// <summary>
+    /// Tests the <see cref="Image"/> class.
+    /// </summary>
+    public class ImageSaveTests : IDisposable
+    {
+        private readonly SaveWatchingImage Image;
+        private readonly Mock<IFileSystem> fileSystem;
+
+        public ImageSaveTests()
+        {
+            this.fileSystem = new Mock<IFileSystem>();
+            this.Image = new SaveWatchingImage(1, 1, this.fileSystem.Object);
+        }
+
+        [Fact]
+        public void SavePath()
+        {
+            Stream stream = new MemoryStream();
+            this.fileSystem.Setup(x => x.OpenWrite("path")).Returns(stream);
+            this.Image.Save("path");
+
+            SaveWatchingImage.OperationDetails operation = this.Image.Saves.Single();
+            Assert.Equal(stream, operation.stream);
+            Assert.Equal(this.Image.CurrentImageFormat.Encoder, operation.encoder);
+            Assert.Null(operation.options);
+        }
+
+        public void Dispose()
+        {
+            this.Image.Dispose();
+        }
+    }
+}

tests/ImageSharp.Tests/Image/SaveWatchingImage.cs

@@ -0,0 +1,39 @@
+
+namespace ImageSharp.Tests
+{
+    using System;
+    using System.IO;
+    using ImageSharp;
+    using Processing;
+    using System.Collections.Generic;
+    using ImageSharp.Formats;
+    using ImageSharp.IO;
+
+    /// <summary>
+    /// Watches but does not actually run the processors against the image.
+    /// </summary>
+    /// <seealso cref="ImageSharp.Image{ImageSharp.Color}" />
+    public class SaveWatchingImage : Image<Color>
+    {
+        public List<OperationDetails> Saves { get; } = new List<OperationDetails>();
+        
+        public SaveWatchingImage(int width, int height, IFileSystem fs = null)
+           : base(width, height, Configuration.CreateDefaultInstance())
+        {
+            //switch out the file system for tests
+            this.Configuration.FileSystem = fs ?? this.Configuration.FileSystem;
+        }
+
+        internal override void SaveInternal(Stream stream, IImageEncoder encoder, IEncoderOptions options)
+        {
+
+        }
+
+        public struct OperationDetails
+        {
+            public Stream stream;
+            public IImageEncoder encoder;
+            public IEncoderOptions options;
+        }
+    }
+}