Factory-walking resource dispatcher + Save scaffolding

Move IResourceNodeFactory to ILSpyX.Abstractions and GuessFileType to ILSpyX.Util
so both UIs can consume them. Wire ResourceEntryNode.Create(Resource) to walk the
MEF-discovered IResourceNodeFactory list (falls back to the generic node), make
Avalonia's ILSpyTreeNode implement ITreeNode for that contract, and register a
ResourcesFileTreeNodeFactory to keep .resources files routed correctly. Adds the
Save virtual on ILSpyTreeNode plus inline "Save" buttons + SaveAsync on
ResourceEntryNode/ResourceTreeNode using a new FilePickers helper around
StorageProvider.SaveFilePickerAsync.

Assisted-by: Claude:claude-opus-4-7:Claude Code

ICSharpCode.ILSpyX/Abstractions/IResourceNodeFactory.cs

@@ -0,0 +1,32 @@
+// Copyright (c) 2011 AlphaSierraPapa for the SharpDevelop Team
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy of this
+// software and associated documentation files (the "Software"), to deal in the Software
+// without restriction, including without limitation the rights to use, copy, modify, merge,
+// publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons
+// to whom the Software is furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in all copies or
+// substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
+// INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
+// PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE
+// FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
+// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+// DEALINGS IN THE SOFTWARE.
+
+using ICSharpCode.Decompiler.Metadata;
+
+namespace ICSharpCode.ILSpyX.Abstractions
+{
+	/// <summary>
+	/// This interface allows plugins to create custom nodes for resources.
+	/// </summary>
+	public interface IResourceNodeFactory
+	{
+		// Null means "this factory doesn't claim the resource"; callers iterate factories until
+		// one returns non-null and otherwise fall back to a generic node.
+		ITreeNode? CreateNode(Resource resource);
+	}
+}

ICSharpCode.ILSpyX/Util/GuessFileType.cs

@@ -0,0 +1,184 @@
+// Copyright (c) 2011 AlphaSierraPapa for the SharpDevelop Team
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy of this
+// software and associated documentation files (the "Software"), to deal in the Software
+// without restriction, including without limitation the rights to use, copy, modify, merge,
+// publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons
+// to whom the Software is furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in all copies or
+// substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
+// INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
+// PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE
+// FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
+// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+// DEALINGS IN THE SOFTWARE.
+
+using System;
+using System.IO;
+using System.Text;
+using System.Xml;
+
+namespace ICSharpCode.ILSpyX.Util
+{
+	/// <summary>
+	/// Static methods for determining the type of a file.
+	/// </summary>
+	public static class GuessFileType
+	{
+		public static FileType DetectFileType(Stream stream)
+		{
+			StreamReader reader;
+			if (stream.Length >= 2)
+			{
+				int firstByte = stream.ReadByte();
+				int secondByte = stream.ReadByte();
+				switch ((firstByte << 8) | secondByte)
+				{
+					case 0xfffe: // UTF-16 LE BOM / UTF-32 LE BOM
+					case 0xfeff: // UTF-16 BE BOM
+						stream.Position -= 2;
+						reader = new StreamReader(stream, detectEncodingFromByteOrderMarks: true);
+						break;
+					case 0xefbb: // start of UTF-8 BOM
+						if (stream.ReadByte() == 0xbf)
+						{
+							reader = new StreamReader(stream, Encoding.UTF8);
+							break;
+						}
+						else
+						{
+							return FileType.Binary;
+						}
+					default:
+						if (IsUTF8(stream, (byte)firstByte, (byte)secondByte))
+						{
+							stream.Position = 0;
+							reader = new StreamReader(stream, Encoding.UTF8);
+							break;
+						}
+						else
+						{
+							return FileType.Binary;
+						}
+				}
+			}
+			else
+			{
+				return FileType.Binary;
+			}
+			// Now we got a StreamReader with the correct encoding
+			// Check for XML now
+			try
+			{
+				XmlTextReader xmlReader = new XmlTextReader(reader);
+				xmlReader.XmlResolver = null;
+				xmlReader.MoveToContent();
+				return FileType.Xml;
+			}
+			catch (XmlException)
+			{
+				return FileType.Text;
+			}
+		}
+
+		static bool IsUTF8(Stream fs, byte firstByte, byte secondByte)
+		{
+			int max = (int)Math.Min(fs.Length, 500000); // look at max. 500 KB
+			const int ASCII = 0;
+			const int Error = 1;
+			const int UTF8 = 2;
+			const int UTF8Sequence = 3;
+			int state = ASCII;
+			int sequenceLength = 0;
+			byte b;
+			for (int i = 0; i < max; i++)
+			{
+				if (i == 0)
+				{
+					b = firstByte;
+				}
+				else if (i == 1)
+				{
+					b = secondByte;
+				}
+				else
+				{
+					b = (byte)fs.ReadByte();
+				}
+				if (b < 0x80)
+				{
+					// normal ASCII character
+					if (state == UTF8Sequence)
+					{
+						state = Error;
+						break;
+					}
+				}
+				else if (b < 0xc0)
+				{
+					// 10xxxxxx : continues UTF8 byte sequence
+					if (state == UTF8Sequence)
+					{
+						--sequenceLength;
+						if (sequenceLength < 0)
+						{
+							state = Error;
+							break;
+						}
+						else if (sequenceLength == 0)
+						{
+							state = UTF8;
+						}
+					}
+					else
+					{
+						state = Error;
+						break;
+					}
+				}
+				else if (b >= 0xc2 && b < 0xf5)
+				{
+					// beginning of byte sequence
+					if (state == UTF8 || state == ASCII)
+					{
+						state = UTF8Sequence;
+						if (b < 0xe0)
+						{
+							sequenceLength = 1; // one more byte following
+						}
+						else if (b < 0xf0)
+						{
+							sequenceLength = 2; // two more bytes following
+						}
+						else
+						{
+							sequenceLength = 3; // three more bytes following
+						}
+					}
+					else
+					{
+						state = Error;
+						break;
+					}
+				}
+				else
+				{
+					// 0xc0, 0xc1, 0xf5 to 0xff are invalid in UTF-8 (see RFC 3629)
+					state = Error;
+					break;
+				}
+			}
+			return state != Error;
+		}
+	}
+
+	public enum FileType
+	{
+		Binary,
+		Text,
+		Xml
+	}
+}

ILSpy/Assets/Icons/Save.svg

@@ -0,0 +1 @@
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 16 16"><style>.icon-canvas-transparent{opacity:0;fill:#f6f6f6}.icon-vs-out{fill:#f6f6f6}.icon-vs-fg{fill:#f0eff1}.icon-vs-action-blue{fill:#00539c}</style><path class="icon-canvas-transparent" d="M16 0v16H0V0h16z" id="canvas"/><path class="icon-vs-out" d="M16 2v14H2.586L0 13.414V2C0 .897.897 0 2 0h12c1.102 0 2 .897 2 2z" id="outline"/><path class="icon-vs-fg" d="M13 3v4H3V3h10zm-9 7v5h2v-3h2v3h4v-5H4z" id="iconFg"/><g id="iconBg"><path class="icon-vs-action-blue" d="M6 12h2v3H6v-3zm9-10v13h-3v-5H4v5H3l-2-2V2a1 1 0 0 1 1-1h12a1 1 0 0 1 1 1zm-2 1H3v4h10V3z"/></g></svg>

ILSpy/Commands/FilePickers.cs

@@ -0,0 +1,93 @@
+// Copyright (c) 2026 AlphaSierraPapa for the SharpDevelop Team
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy of this
+// software and associated documentation files (the "Software"), to deal in the Software
+// without restriction, including without limitation the rights to use, copy, modify, merge,
+// publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons
+// to whom the Software is furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in all copies or
+// substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
+// INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
+// PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE
+// FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
+// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+// DEALINGS IN THE SOFTWARE.
+
+using System.Collections.Generic;
+using System.IO;
+using System.Threading.Tasks;
+
+using global::Avalonia.Controls.ApplicationLifetimes;
+using global::Avalonia.Platform.Storage;
+
+namespace ILSpy.Commands
+{
+	/// <summary>
+	/// Helpers around <see cref="IStorageProvider"/> for save dialogs. Mirrors the WPF
+	/// SaveFileDialog Filter API ("Display|*.ext;*.ext|...") so callers can keep the existing
+	/// strings.
+	/// </summary>
+	public static class FilePickers
+	{
+		/// <summary>
+		/// Shows a save-file picker. <paramref name="filter"/> uses WPF SaveFileDialog syntax —
+		/// pairs of <c>display|patterns</c> joined by <c>|</c>. <paramref name="defaultFileName"/>
+		/// pre-fills the file name (no path). Returns the selected absolute path, or <c>null</c>
+		/// if the user cancelled.
+		/// </summary>
+		public static async Task<string?> SaveAsync(
+			string filter,
+			string? defaultFileName = null,
+			string? title = null)
+		{
+			var owner = (global::Avalonia.Application.Current?.ApplicationLifetime
+				as IClassicDesktopStyleApplicationLifetime)?.MainWindow;
+			if (owner == null)
+				return null;
+
+			var fileTypes = ParseFilter(filter);
+			var suggested = defaultFileName != null
+				? Path.GetFileName(defaultFileName)
+				: null;
+
+			var file = await owner.StorageProvider.SaveFilePickerAsync(new FilePickerSaveOptions {
+				Title = title,
+				FileTypeChoices = fileTypes,
+				SuggestedFileName = suggested,
+				DefaultExtension = fileTypes.Count > 0 ? GuessExtension(fileTypes[0]) : null,
+			});
+
+			return file?.TryGetLocalPath();
+		}
+
+		/// <summary>"PNG (*.png)|*.png|All files|*.*" → two file types.</summary>
+		static IReadOnlyList<FilePickerFileType> ParseFilter(string filter)
+		{
+			var result = new List<FilePickerFileType>();
+			var parts = filter.Split('|');
+			for (int i = 0; i + 1 < parts.Length; i += 2)
+			{
+				var display = parts[i];
+				var patterns = parts[i + 1].Split(';');
+				result.Add(new FilePickerFileType(display) { Patterns = patterns });
+			}
+			return result;
+		}
+
+		static string? GuessExtension(FilePickerFileType type)
+		{
+			if (type.Patterns is null)
+				return null;
+			foreach (var p in type.Patterns)
+			{
+				// "*.ext" → "ext"; bare "*" or "*.*" yields no useful extension.
+				if (p.StartsWith("*.", System.StringComparison.Ordinal) && p.Length > 2 && p[2] != '*')
+					return p[2..];
+			}
+			return null;
+		}
+	}
+}

ILSpy/Images.cs

@@ -73,6 +73,7 @@ namespace ILSpy.Images
 		public static readonly IImage Back = LoadSvg(nameof(Back));
 		public static readonly IImage Forward = LoadSvg(nameof(Forward));
 		public static readonly IImage Open = LoadSvg(nameof(Open));
+		public static readonly IImage Save = LoadSvg(nameof(Save));
 
 		// Containers
 		public static readonly IImage Namespace = LoadSvg(nameof(Namespace));

ILSpy/TreeNodes/ILSpyTreeNode.cs

@@ -16,7 +16,11 @@
 // OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
 // DEALINGS IN THE SOFTWARE.
 
+using System.Collections.Generic;
+using System.Linq;
+
 using ICSharpCode.Decompiler;
+using ICSharpCode.ILSpyX.Abstractions;
 using ICSharpCode.ILSpyX.TreeView;
 
 using ILSpy.AppEnv;
@@ -24,8 +28,10 @@ using ILSpy.Languages;
 
 namespace ILSpy.TreeNodes
 {
-	public abstract class ILSpyTreeNode : SharpTreeNode
+	public abstract class ILSpyTreeNode : SharpTreeNode, ITreeNode
 	{
+		IEnumerable<ITreeNode> ITreeNode.Children => Children.OfType<ILSpyTreeNode>();
+
 		static LanguageService? cachedLanguageService;
 
 		/// <summary>
@@ -35,6 +41,15 @@ namespace ILSpy.TreeNodes
 		protected static LanguageService LanguageService
 			=> cachedLanguageService ??= AppComposition.Current.GetExport<LanguageService>();
 
+		/// <summary>
+		/// All MEF-discovered <see cref="IResourceNodeFactory"/> instances. Resource-tree nodes
+		/// walk this list to dispatch a <see cref="ICSharpCode.Decompiler.Metadata.Resource"/> to
+		/// the right specialised node (image / xml / .resources / …) before falling back to the
+		/// generic node.
+		/// </summary>
+		protected static ICollection<IResourceNodeFactory> ResourceNodeFactories { get; }
+			= AppComposition.Current.GetExports<IResourceNodeFactory>().ToArray();
+
 		public Language Language => LanguageService.CurrentLanguage;
 
 		/// <summary>
@@ -54,5 +69,13 @@ namespace ILSpy.TreeNodes
 		{
 			language.WriteCommentLine(output, Text?.ToString() ?? GetType().Name);
 		}
+
+		/// <summary>
+		/// Special "Save" handling for nodes that aren't textual code. Default returns false,
+		/// meaning the host should use the regular decompile-to-file path. Override and return
+		/// true after writing the node's content to handle Save inline (e.g. raw byte copy for
+		/// embedded resources).
+		/// </summary>
+		public virtual bool Save() => false;
 	}
 }

ILSpy/TreeNodes/ResourceEntryNode.cs

@@ -18,11 +18,17 @@
 
 using System;
 using System.IO;
+using System.Linq;
+using System.Threading.Tasks;
 
 using ICSharpCode.Decompiler;
+using ICSharpCode.Decompiler.CSharp.ProjectDecompiler;
 using ICSharpCode.Decompiler.IL;
+using ICSharpCode.Decompiler.Metadata;
 
+using ILSpy.Commands;
 using ILSpy.Languages;
+using ILSpy.TextView;
 
 namespace ILSpy.TreeNodes
 {
@@ -51,9 +57,48 @@ namespace ILSpy.TreeNodes
 		{
 			using var data = OpenStream();
 			language.WriteCommentLine(output, $"{key} = {data.Length} bytes");
+			if (output is ISmartTextOutput smart)
+			{
+				smart.WriteLine();
+				smart.AddButton(Images.Images.Save, "Save", async (_, _) => await SaveAsync().ConfigureAwait(false));
+				smart.WriteLine();
+			}
+		}
+
+		public override bool Save()
+		{
+			_ = SaveAsync();
+			return true;
+		}
+
+		async Task SaveAsync()
+		{
+			var defaultName = Path.GetFileName(WholeProjectDecompiler.SanitizeFileName(key));
+			var path = await FilePickers.SaveAsync("All files|*.*", defaultName).ConfigureAwait(false);
+			if (path == null)
+				return;
+			using var src = OpenStream();
+			using var dst = File.Create(path);
+			src.CopyTo(dst);
 		}
 
 		public static ILSpyTreeNode Create(string name, byte[] data)
 			=> new ResourceEntryNode(name, () => new MemoryStream(data));
+
+		/// <summary>
+		/// Walks <see cref="ILSpyTreeNode.ResourceNodeFactories"/> and returns the first node any
+		/// factory builds for <paramref name="resource"/>. Falls back to a plain
+		/// <see cref="ResourceTreeNode"/> when no factory claims it. The single dispatch entry
+		/// point used by both <see cref="ResourceListTreeNode"/> and packages.
+		/// </summary>
+		public static ILSpyTreeNode Create(Resource resource)
+		{
+			ArgumentNullException.ThrowIfNull(resource);
+			return ResourceNodeFactories
+				.Select(f => f.CreateNode(resource))
+				.OfType<ILSpyTreeNode>()
+				.FirstOrDefault()
+				?? new ResourceTreeNode(resource);
+		}
 	}
 }

ILSpy/TreeNodes/ResourceTreeNode.cs

@@ -17,12 +17,17 @@
 // DEALINGS IN THE SOFTWARE.
 
 using System;
+using System.IO;
+using System.Threading.Tasks;
 
 using ICSharpCode.Decompiler;
+using ICSharpCode.Decompiler.CSharp.ProjectDecompiler;
 using ICSharpCode.Decompiler.IL;
 using ICSharpCode.Decompiler.Metadata;
 
+using ILSpy.Commands;
 using ILSpy.Languages;
+using ILSpy.TextView;
 
 namespace ILSpy.TreeNodes
 {
@@ -49,14 +54,36 @@ namespace ILSpy.TreeNodes
 			var sizeInBytes = Resource.TryGetLength();
 			var sizeInBytesText = sizeInBytes == null ? "" : ", " + sizeInBytes + " bytes";
 			language.WriteCommentLine(output, $"{Resource.Name} ({Resource.ResourceType}, {Resource.Attributes}{sizeInBytesText})");
+			if (output is ISmartTextOutput smart)
+			{
+				smart.WriteLine();
+				smart.AddButton(Images.Images.Save, "Save", async (_, _) => await SaveAsync().ConfigureAwait(false));
+				smart.WriteLine();
+			}
 		}
 
-		public static ILSpyTreeNode Create(Resource resource)
+		public override bool Save()
 		{
-			ArgumentNullException.ThrowIfNull(resource);
-			if (resource.Name.EndsWith(".resources", StringComparison.OrdinalIgnoreCase))
-				return new ResourcesFileTreeNode(resource);
-			return new ResourceTreeNode(resource);
+			_ = SaveAsync();
+			return true;
 		}
+
+		async Task SaveAsync()
+		{
+			var defaultName = Path.GetFileName(WholeProjectDecompiler.SanitizeFileName(Resource.Name));
+			var path = await FilePickers.SaveAsync("All files|*.*", defaultName).ConfigureAwait(false);
+			if (path == null)
+				return;
+			using var src = Resource.TryOpenStream();
+			if (src == null)
+				return;
+			src.Position = 0;
+			using var dst = File.Create(path);
+			src.CopyTo(dst);
+		}
+
+		// Keep the symmetric name from WPF: callers can use ResourceTreeNode.Create or
+		// ResourceEntryNode.Create interchangeably.
+		public static ILSpyTreeNode Create(Resource resource) => ResourceEntryNode.Create(resource);
 	}
 }

ILSpy/TreeNodes/ResourcesFileTreeNode.cs

@@ -18,17 +18,31 @@
 
 using System;
 using System.Collections.Generic;
+using System.Composition;
 using System.IO;
 using System.Linq;
 
 using ICSharpCode.Decompiler;
 using ICSharpCode.Decompiler.Metadata;
 using ICSharpCode.Decompiler.Util;
+using ICSharpCode.ILSpyX.Abstractions;
 
 using ILSpy.Languages;
 
 namespace ILSpy.TreeNodes
 {
+	[Export(typeof(IResourceNodeFactory))]
+	[Shared]
+	sealed class ResourcesFileTreeNodeFactory : IResourceNodeFactory
+	{
+		public ITreeNode? CreateNode(Resource resource)
+		{
+			if (resource.Name.EndsWith(".resources", StringComparison.OrdinalIgnoreCase))
+				return new ResourcesFileTreeNode(resource);
+			return null;
+		}
+	}
+
 	/// <summary>
 	/// A <c>.resources</c> file embedded in an assembly. Children are
 	/// <see cref="ResourceEntryNode"/> for byte-payload entries; string entries are