Merge pull request #3191 from icsharpcode/file-loaders

Add IFileLoader API

ICSharpCode.Decompiler.Tests/RoundtripAssembly.cs

@@ -289,8 +289,8 @@ namespace ICSharpCode.Decompiler.Tests
 
 		class TestProjectDecompiler : WholeProjectDecompiler
 		{
-			public TestProjectDecompiler(Guid projecGuid, IAssemblyResolver resolver, AssemblyReferenceClassifier assemblyReferenceClassifier, DecompilerSettings settings)
-				: base(settings, projecGuid, resolver, assemblyReferenceClassifier, debugInfoProvider: null)
+			public TestProjectDecompiler(Guid projectGuid, IAssemblyResolver resolver, AssemblyReferenceClassifier assemblyReferenceClassifier, DecompilerSettings settings)
+				: base(settings, projectGuid, resolver, null, assemblyReferenceClassifier, debugInfoProvider: null)
 			{
 			}
 		}

ICSharpCode.Decompiler/CSharp/ProjectDecompiler/IProjectFileWriter.cs

@@ -27,7 +27,7 @@ namespace ICSharpCode.Decompiler.CSharp.ProjectDecompiler
 	/// An interface for a service that creates and writes a project file structure
 	/// for a specific module being decompiled.
 	/// </summary>
-	interface IProjectFileWriter
+	public interface IProjectFileWriter
 	{
 		/// <summary>
 		/// Writes the content of a new project file for the specified <paramref name="module"/> being decompiled.

ICSharpCode.Decompiler/CSharp/ProjectDecompiler/IProjectInfoProvider.cs

@@ -25,7 +25,7 @@ namespace ICSharpCode.Decompiler.CSharp.ProjectDecompiler
 	/// <summary>
 	/// An interface that provides common information for a project being decompiled to.
 	/// </summary>
-	interface IProjectInfoProvider
+	public interface IProjectInfoProvider
 	{
 		/// <summary>
 		/// Gets the assembly resolver active for the project.

ICSharpCode.Decompiler/CSharp/ProjectDecompiler/WholeProjectDecompiler.cs

@@ -99,16 +99,17 @@ namespace ICSharpCode.Decompiler.CSharp.ProjectDecompiler
 		#endregion
 
 		public WholeProjectDecompiler(IAssemblyResolver assemblyResolver)
-			: this(new DecompilerSettings(), assemblyResolver, assemblyReferenceClassifier: null, debugInfoProvider: null)
+			: this(new DecompilerSettings(), assemblyResolver, projectWriter: null, assemblyReferenceClassifier: null, debugInfoProvider: null)
 		{
 		}
 
 		public WholeProjectDecompiler(
 			DecompilerSettings settings,
 			IAssemblyResolver assemblyResolver,
+			IProjectFileWriter projectWriter,
 			AssemblyReferenceClassifier assemblyReferenceClassifier,
 			IDebugInfoProvider debugInfoProvider)
-			: this(settings, Guid.NewGuid(), assemblyResolver, assemblyReferenceClassifier, debugInfoProvider)
+			: this(settings, Guid.NewGuid(), assemblyResolver, projectWriter, assemblyReferenceClassifier, debugInfoProvider)
 		{
 		}
 
@@ -116,6 +117,7 @@ namespace ICSharpCode.Decompiler.CSharp.ProjectDecompiler
 			DecompilerSettings settings,
 			Guid projectGuid,
 			IAssemblyResolver assemblyResolver,
+			IProjectFileWriter projectWriter,
 			AssemblyReferenceClassifier assemblyReferenceClassifier,
 			IDebugInfoProvider debugInfoProvider)
 		{
@@ -124,7 +126,7 @@ namespace ICSharpCode.Decompiler.CSharp.ProjectDecompiler
 			AssemblyResolver = assemblyResolver ?? throw new ArgumentNullException(nameof(assemblyResolver));
 			AssemblyReferenceClassifier = assemblyReferenceClassifier ?? new AssemblyReferenceClassifier();
 			DebugInfoProvider = debugInfoProvider;
-			projectWriter = Settings.UseSdkStyleProjectFormat ? ProjectFileWriterSdkStyle.Create() : ProjectFileWriterDefault.Create();
+			this.projectWriter = projectWriter ?? (Settings.UseSdkStyleProjectFormat ? ProjectFileWriterSdkStyle.Create() : ProjectFileWriterDefault.Create());
 		}
 
 		// per-run members

ICSharpCode.ILSpyCmd/IlspyCmdProgram.cs

@@ -24,8 +24,6 @@ using McMaster.Extensions.CommandLineUtils;
 
 using Microsoft.Extensions.Hosting;
 
-using NuGet.Versioning;
-
 namespace ICSharpCode.ILSpyCmd
 {
 	[Command(Name = "ilspycmd", Description = "dotnet tool for decompiling .NET assemblies and generating portable PDBs",
@@ -314,7 +312,7 @@ Examples:
 			{
 				resolver.AddSearchDirectory(path);
 			}
-			var decompiler = new WholeProjectDecompiler(GetSettings(module), resolver, resolver, TryLoadPDB(module));
+			var decompiler = new WholeProjectDecompiler(GetSettings(module), resolver, null, resolver, TryLoadPDB(module));
 			using (var projectFileWriter = new StreamWriter(File.OpenWrite(projectFileName)))
 				return decompiler.DecompileProject(module, Path.GetDirectoryName(projectFileName), projectFileWriter);
 		}

ICSharpCode.ILSpyX/AssemblyList.cs

@@ -30,6 +30,7 @@ using System.Threading.Tasks;
 using System.Xml.Linq;
 
 using ICSharpCode.ILSpyX.Extensions;
+using ICSharpCode.ILSpyX.FileLoaders;
 
 namespace ICSharpCode.ILSpyX
 {
@@ -128,6 +129,7 @@ namespace ICSharpCode.ILSpyX
 
 		public bool ApplyWinRTProjections { get; set; }
 		public bool UseDebugSymbols { get; set; }
+		public FileLoaderRegistry LoaderRegistry => this.manager.LoaderRegistry;
 
 		/// <summary>
 		/// Gets the loaded assemblies. This method is thread-safe.
@@ -279,7 +281,7 @@ namespace ICSharpCode.ILSpyX
 		{
 			file = Path.GetFullPath(file);
 			return OpenAssembly(file, () => {
-				var newAsm = new LoadedAssembly(this, file, applyWinRTProjections: ApplyWinRTProjections, useDebugSymbols: UseDebugSymbols);
+				var newAsm = new LoadedAssembly(this, file, fileLoaders: manager?.LoaderRegistry, applyWinRTProjections: ApplyWinRTProjections, useDebugSymbols: UseDebugSymbols);
 				newAsm.IsAutoLoaded = isAutoLoaded;
 				return newAsm;
 			});
@@ -293,6 +295,7 @@ namespace ICSharpCode.ILSpyX
 			file = Path.GetFullPath(file);
 			return OpenAssembly(file, () => {
 				var newAsm = new LoadedAssembly(this, file, stream: Task.FromResult(stream),
+					fileLoaders: manager?.LoaderRegistry,
 					applyWinRTProjections: ApplyWinRTProjections, useDebugSymbols: UseDebugSymbols);
 				newAsm.IsAutoLoaded = isAutoLoaded;
 				return newAsm;
@@ -345,6 +348,7 @@ namespace ICSharpCode.ILSpyX
 					return null;
 
 				var newAsm = new LoadedAssembly(this, file, stream: Task.FromResult<Stream?>(stream),
+					fileLoaders: manager?.LoaderRegistry,
 					applyWinRTProjections: ApplyWinRTProjections, useDebugSymbols: UseDebugSymbols);
 				newAsm.IsAutoLoaded = target.IsAutoLoaded;
 
@@ -374,6 +378,7 @@ namespace ICSharpCode.ILSpyX
 			if (index < 0)
 				return null;
 			var newAsm = new LoadedAssembly(this, target.FileName, pdbFileName: target.PdbFileName,
+				fileLoaders: manager?.LoaderRegistry,
 				applyWinRTProjections: ApplyWinRTProjections, useDebugSymbols: UseDebugSymbols);
 			newAsm.IsAutoLoaded = target.IsAutoLoaded;
 			lock (lockObj)

ICSharpCode.ILSpyX/AssemblyListManager.cs

@@ -23,6 +23,7 @@ using System.Linq;
 using System.Xml.Linq;
 
 using ICSharpCode.Decompiler.Metadata;
+using ICSharpCode.ILSpyX.FileLoaders;
 using ICSharpCode.ILSpyX.Settings;
 
 namespace ICSharpCode.ILSpyX
@@ -59,6 +60,8 @@ namespace ICSharpCode.ILSpyX
 
 		public ObservableCollection<string> AssemblyLists { get; } = new ObservableCollection<string>();
 
+		public FileLoaderRegistry LoaderRegistry { get; } = new FileLoaderRegistry();
+
 		/// <summary>
 		/// Loads an assembly list from the ILSpySettings.
 		/// If no list with the specified name is found, the default list is loaded instead.

ICSharpCode.ILSpyX/AssemblyListSnapshot.cs

@@ -27,6 +27,7 @@ using System.Threading.Tasks;
 using ICSharpCode.Decompiler.Metadata;
 using ICSharpCode.Decompiler.Util;
 using ICSharpCode.ILSpyX.Extensions;
+using ICSharpCode.ILSpyX.FileLoaders;
 
 namespace ICSharpCode.ILSpyX
 {
@@ -156,7 +157,7 @@ namespace ICSharpCode.ILSpyX
 
 			foreach (var asm in assemblies)
 			{
-				LoadedAssembly.LoadResult result;
+				LoadResult result;
 				try
 				{
 					result = await asm.GetLoadResultAsync().ConfigureAwait(false);

ICSharpCode.ILSpyX/FileLoaders/ArchiveFileLoader.cs

@@ -0,0 +1,40 @@
+// Copyright (c) 2024 Siegfried Pammer
+// 
+// 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.IO;
+using System.Threading.Tasks;
+
+namespace ICSharpCode.ILSpyX.FileLoaders
+{
+	public sealed class ArchiveFileLoader : IFileLoader
+	{
+		public Task<LoadResult?> Load(string fileName, Stream stream, FileLoadSettings settings)
+		{
+			try
+			{
+				var zip = LoadedPackage.FromZipFile(fileName);
+				var result = zip != null ? new LoadResult { Package = zip } : null;
+				return Task.FromResult(result);
+			}
+			catch (InvalidDataException)
+			{
+				return Task.FromResult<LoadResult?>(null);
+			}
+		}
+	}
+}

ICSharpCode.ILSpyX/FileLoaders/BundleFileLoader.cs

@@ -0,0 +1,33 @@
+// Copyright (c) 2024 Siegfried Pammer
+// 
+// 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.IO;
+using System.Threading.Tasks;
+
+namespace ICSharpCode.ILSpyX.FileLoaders
+{
+	public sealed class BundleFileLoader : IFileLoader
+	{
+		public Task<LoadResult?> Load(string fileName, Stream stream, FileLoadSettings settings)
+		{
+			var bundle = LoadedPackage.FromBundle(fileName);
+			var result = bundle != null ? new LoadResult { Package = bundle } : null;
+			return Task.FromResult(result);
+		}
+	}
+}

ICSharpCode.ILSpyX/FileLoaders/FileLoaderRegistry.cs

@@ -0,0 +1,49 @@
+// Copyright (c) 2024 Siegfried Pammer
+// 
+// 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.Collections.Generic;
+
+namespace ICSharpCode.ILSpyX.FileLoaders
+{
+	public sealed class FileLoaderRegistry
+	{
+		readonly List<IFileLoader> registeredLoaders = new List<IFileLoader>();
+
+		public IReadOnlyList<IFileLoader> RegisteredLoaders => registeredLoaders;
+
+		public void Register(IFileLoader loader)
+		{
+			if (loader is null)
+			{
+				throw new ArgumentNullException(nameof(loader));
+			}
+
+			registeredLoaders.Add(loader);
+		}
+
+		public FileLoaderRegistry()
+		{
+			Register(new XamarinCompressedFileLoader());
+			Register(new WebCilFileLoader());
+			Register(new MetadataFileLoader());
+			Register(new BundleFileLoader());
+			Register(new ArchiveFileLoader());
+		}
+	}
+}

ICSharpCode.ILSpyX/FileLoaders/LoadResult.cs

@@ -0,0 +1,40 @@
+// Copyright (c) 2024 Siegfried Pammer
+// 
+// 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.Threading.Tasks;
+
+using ICSharpCode.Decompiler.Metadata;
+
+namespace ICSharpCode.ILSpyX.FileLoaders
+{
+	public sealed class LoadResult
+	{
+		public MetadataFile? MetadataFile { get; init; }
+		public Exception? FileLoadException { get; init; }
+		public LoadedPackage? Package { get; init; }
+	}
+
+	public record FileLoadSettings(bool ApplyWinRTProjections);
+
+	public interface IFileLoader
+	{
+		Task<LoadResult?> Load(string fileName, Stream stream, FileLoadSettings settings);
+	}
+}

ICSharpCode.ILSpyX/FileLoaders/MetadataFileLoader.cs

@@ -0,0 +1,48 @@
+// Copyright (c) 2024 Siegfried Pammer
+// 
+// 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.Reflection.Metadata;
+using System.Threading.Tasks;
+
+using ICSharpCode.Decompiler.Metadata;
+
+using static ICSharpCode.Decompiler.Metadata.MetadataFile;
+
+namespace ICSharpCode.ILSpyX.FileLoaders
+{
+	public sealed class MetadataFileLoader : IFileLoader
+	{
+		public Task<LoadResult?> Load(string fileName, Stream stream, FileLoadSettings settings)
+		{
+			try
+			{
+				var kind = Path.GetExtension(fileName).Equals(".pdb", StringComparison.OrdinalIgnoreCase)
+					? MetadataFileKind.ProgramDebugDatabase : MetadataFileKind.Metadata;
+				var metadata = MetadataReaderProvider.FromMetadataStream(stream, MetadataStreamOptions.PrefetchMetadata | MetadataStreamOptions.LeaveOpen);
+				var metadataFile = new MetadataFile(kind, fileName, metadata);
+				return Task.FromResult<LoadResult?>(new LoadResult { MetadataFile = metadataFile });
+			}
+			catch (BadImageFormatException)
+			{
+				return Task.FromResult<LoadResult?>(null);
+			}
+		}
+	}
+}

ICSharpCode.ILSpyX/FileLoaders/WebCilFileLoader.cs

@@ -0,0 +1,40 @@
+// Copyright (c) 2024 Siegfried Pammer
+// 
+// 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.IO;
+using System.Reflection.Metadata;
+using System.Threading.Tasks;
+
+using ICSharpCode.Decompiler.Metadata;
+
+namespace ICSharpCode.ILSpyX.FileLoaders
+{
+	public sealed class WebCilFileLoader : IFileLoader
+	{
+		public Task<LoadResult?> Load(string fileName, Stream stream, FileLoadSettings settings)
+		{
+			MetadataReaderOptions options = settings.ApplyWinRTProjections
+						? MetadataReaderOptions.ApplyWindowsRuntimeProjections
+						: MetadataReaderOptions.None;
+
+			var wasm = WebCilFile.FromStream(fileName, options);
+			var result = wasm != null ? new LoadResult { MetadataFile = wasm } : null;
+			return Task.FromResult(result);
+		}
+	}
+}

ICSharpCode.ILSpyX/FileLoaders/XamarinCompressedFileLoader.cs

@@ -0,0 +1,73 @@
+// Copyright (c) 2024 Siegfried Pammer
+// 
+// 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.Buffers;
+using System.IO;
+using System.Reflection.Metadata;
+using System.Reflection.PortableExecutable;
+using System.Text;
+using System.Threading.Tasks;
+
+using ICSharpCode.Decompiler.Metadata;
+
+using K4os.Compression.LZ4;
+
+namespace ICSharpCode.ILSpyX.FileLoaders
+{
+	public sealed class XamarinCompressedFileLoader : IFileLoader
+	{
+		public async Task<LoadResult?> Load(string fileName, Stream stream, FileLoadSettings settings)
+		{
+			const uint CompressedDataMagic = 0x5A4C4158; // Magic used for Xamarin compressed module header ('XALZ', little-endian)
+			using var fileReader = new BinaryReader(stream, Encoding.UTF8, leaveOpen: true);
+			// Read compressed file header
+			var magic = fileReader.ReadUInt32();
+			if (magic != CompressedDataMagic)
+				return null;
+			_ = fileReader.ReadUInt32(); // skip index into descriptor table, unused
+			int uncompressedLength = (int)fileReader.ReadUInt32();
+			int compressedLength = (int)stream.Length;  // Ensure we read all of compressed data
+			ArrayPool<byte> pool = ArrayPool<byte>.Shared;
+			var src = pool.Rent(compressedLength);
+			var dst = pool.Rent(uncompressedLength);
+			try
+			{
+				// fileReader stream position is now at compressed module data
+				await stream.ReadAsync(src, 0, compressedLength).ConfigureAwait(false);
+				// Decompress
+				LZ4Codec.Decode(src, 0, compressedLength, dst, 0, uncompressedLength);
+				// Load module from decompressed data buffer
+				using (var uncompressedStream = new MemoryStream(dst, writable: false))
+				{
+					MetadataReaderOptions options = settings.ApplyWinRTProjections
+						? MetadataReaderOptions.ApplyWindowsRuntimeProjections
+						: MetadataReaderOptions.None;
+
+					return new LoadResult {
+						MetadataFile = new PEFile(fileName, stream, PEStreamOptions.PrefetchEntireImage, metadataOptions: options)
+					};
+				}
+			}
+			finally
+			{
+				pool.Return(dst);
+				pool.Return(src);
+			}
+		}
+	}
+}

ICSharpCode.ILSpyX/LoadedAssembly.cs

@@ -17,7 +17,6 @@
 // DEALINGS IN THE SOFTWARE.
 
 using System;
-using System.Buffers;
 using System.Diagnostics;
 using System.IO;
 using System.Reflection.Metadata;
@@ -31,12 +30,9 @@ using ICSharpCode.Decompiler.Metadata;
 using ICSharpCode.Decompiler.TypeSystem;
 using ICSharpCode.Decompiler.TypeSystem.Implementation;
 using ICSharpCode.Decompiler.Util;
+using ICSharpCode.ILSpyX.FileLoaders;
 using ICSharpCode.ILSpyX.PdbProvider;
 
-using K4os.Compression.LZ4;
-
-using static ICSharpCode.Decompiler.Metadata.MetadataFile;
-
 
 #nullable enable
 
@@ -65,47 +61,29 @@ namespace ICSharpCode.ILSpyX
 		/// </summary>
 		internal static readonly ConditionalWeakTable<MetadataFile, LoadedAssembly> loadedAssemblies = new ConditionalWeakTable<MetadataFile, LoadedAssembly>();
 
-		public sealed class LoadResult
-		{
-			public MetadataFile? MetadataFile { get; }
-			public PEFile? PEFile => MetadataFile as PEFile;
-			public Exception? FileLoadException { get; }
-			public LoadedPackage? Package { get; }
-
-			public LoadResult(PEFile peFile)
-			{
-				this.MetadataFile = peFile ?? throw new ArgumentNullException(nameof(peFile));
-			}
-			public LoadResult(Exception fileLoadException, LoadedPackage package)
-			{
-				this.FileLoadException = fileLoadException ?? throw new ArgumentNullException(nameof(fileLoadException));
-				this.Package = package ?? throw new ArgumentNullException(nameof(package));
-			}
-			public LoadResult(Exception fileLoadException, MetadataFile metadataFile)
-			{
-				this.FileLoadException = fileLoadException ?? throw new ArgumentNullException(nameof(fileLoadException));
-				this.MetadataFile = metadataFile ?? throw new ArgumentNullException(nameof(metadataFile));
-			}
-		}
-
 		readonly Task<LoadResult> loadingTask;
 		readonly AssemblyList assemblyList;
 		readonly string fileName;
 		readonly string shortName;
 		readonly IAssemblyResolver? providedAssemblyResolver;
+		readonly FileLoaderRegistry? fileLoaders;
 		readonly bool applyWinRTProjections;
 		readonly bool useDebugSymbols;
 
 		public LoadedAssembly? ParentBundle { get; }
 
 		public LoadedAssembly(AssemblyList assemblyList, string fileName,
-			Task<Stream?>? stream = null, IAssemblyResolver? assemblyResolver = null, string? pdbFileName = null,
+			Task<Stream?>? stream = null,
+			FileLoaderRegistry? fileLoaders = null,
+			IAssemblyResolver? assemblyResolver = null,
+			string? pdbFileName = null,
 			bool applyWinRTProjections = false, bool useDebugSymbols = false)
 		{
 			this.assemblyList = assemblyList ?? throw new ArgumentNullException(nameof(assemblyList));
 			this.fileName = fileName ?? throw new ArgumentNullException(nameof(fileName));
 			this.PdbFileName = pdbFileName;
 			this.providedAssemblyResolver = assemblyResolver;
+			this.fileLoaders = fileLoaders;
 			this.applyWinRTProjections = applyWinRTProjections;
 			this.useDebugSymbols = useDebugSymbols;
 
@@ -114,9 +92,10 @@ namespace ICSharpCode.ILSpyX
 		}
 
 		public LoadedAssembly(LoadedAssembly bundle, string fileName, Task<Stream?>? stream,
+			FileLoaderRegistry? fileLoaders = null,
 			IAssemblyResolver? assemblyResolver = null,
 			bool applyWinRTProjections = false, bool useDebugSymbols = false)
-			: this(bundle.assemblyList, fileName, stream, assemblyResolver, null,
+			: this(bundle.assemblyList, fileName, stream, fileLoaders, assemblyResolver, null,
 				  applyWinRTProjections, useDebugSymbols)
 		{
 			this.ParentBundle = bundle;
@@ -180,7 +159,7 @@ namespace ICSharpCode.ILSpyX
 			if (loadResult.MetadataFile != null)
 				return loadResult.MetadataFile;
 			else
-				throw loadResult.FileLoadException!;
+				throw loadResult.FileLoadException ?? new MetadataFileNotSupportedException();
 		}
 
 		/// <summary>
@@ -334,145 +313,84 @@ namespace ICSharpCode.ILSpyX
 
 		async Task<LoadResult> LoadAsync(Task<Stream?>? streamTask)
 		{
-			// runs on background thread
-			var stream = streamTask != null ? await streamTask.ConfigureAwait(false) : null;
-			if (stream != null)
-			{
-				// Read the module from a precrafted stream
-				if (!stream.CanSeek)
+			using var stream = await PrepareStream();
+			FileLoadSettings settings = new FileLoadSettings(applyWinRTProjections);
+
+			LoadResult? result = null;
+
+			if (fileLoaders != null)
 			{
-					var memoryStream = new MemoryStream();
-					stream.CopyTo(memoryStream);
-					stream.Close();
-					memoryStream.Position = 0;
-					stream = memoryStream;
-				}
-				var streamOptions = stream is MemoryStream ? PEStreamOptions.PrefetchEntireImage : PEStreamOptions.Default;
-				return LoadAssembly(stream, streamOptions, applyWinRTProjections);
-			}
-			// Read the module from disk
-			Exception loadAssemblyException;
-			try
+				foreach (var loader in fileLoaders.RegisteredLoaders)
 				{
-				using (var fileStream = new FileStream(fileName, FileMode.Open, FileAccess.Read))
+					stream.Position = 0;
+					result = await loader.Load(fileName, stream, settings).ConfigureAwait(false);
+					if (result != null)
 					{
-					return LoadAssembly(fileStream, PEStreamOptions.PrefetchEntireImage, applyWinRTProjections);
+						break;
 					}
 				}
-			catch (MetadataFileNotSupportedException ex)
-			{
-				loadAssemblyException = ex;
 			}
-			catch (BadImageFormatException ex)
+
+			if (result == null)
 			{
-				loadAssemblyException = ex;
-			}
-			// Maybe its a compressed Xamarin/Mono assembly, see https://github.com/xamarin/xamarin-android/pull/4686
+				stream.Position = 0;
 				try
 				{
-				return LoadCompressedAssembly(fileName);
+					MetadataReaderOptions options = applyWinRTProjections
+						? MetadataReaderOptions.ApplyWindowsRuntimeProjections
+						: MetadataReaderOptions.None;
+
+					PEFile module = new PEFile(fileName, stream, PEStreamOptions.PrefetchEntireImage, metadataOptions: options);
+					result = new LoadResult { MetadataFile = module };
 				}
-			catch (InvalidDataException)
+				catch (Exception ex)
 				{
-				// Not a compressed module, try other options below
+					result = new LoadResult { FileLoadException = ex };
 				}
-			// If it's not a .NET module, maybe it's a single-file bundle
-			var bundle = LoadedPackage.FromBundle(fileName);
-			if (bundle != null)
-			{
-				bundle.LoadedAssembly = this;
-				return new LoadResult(loadAssemblyException, bundle);
 			}
-			// If it's not a .NET module, maybe it's a WASM module
-			var wasm = WebCilFile.FromStream(fileName);
-			if (wasm != null)
+
+			if (result.MetadataFile != null)
 			{
 				lock (loadedAssemblies)
 				{
-					loadedAssemblies.Add(wasm, this);
-				}
-				return new LoadResult(loadAssemblyException, wasm);
-			}
-			// If it's not a .NET module, maybe it's a zip archive (e.g. .nupkg)
-			try
-			{
-				var zip = LoadedPackage.FromZipFile(fileName);
-				zip.LoadedAssembly = this;
-				return new LoadResult(loadAssemblyException, zip);
+					loadedAssemblies.Add(result.MetadataFile, this);
 				}
-			catch (InvalidDataException)
-			{
-				// Not a compressed module, try other options below
-			}
-			// or it could be a standalone portable PDB
-			try
-			{
-				using (var fileStream = new FileStream(fileName, FileMode.Open, FileAccess.Read))
-				{
-					var kind = Path.GetExtension(fileName).Equals(".pdb", StringComparison.OrdinalIgnoreCase) ? MetadataFileKind.ProgramDebugDatabase : MetadataFileKind.Metadata;
-					var metadata = MetadataReaderProvider.FromMetadataStream(fileStream, MetadataStreamOptions.PrefetchMetadata);
-					var metadataFile = new MetadataFile(kind, fileName, metadata);
-					lock (loadedAssemblies)
+
+				if (result.MetadataFile is PEFile module)
 				{
-						loadedAssemblies.Add(metadataFile, this);
-					}
-					return new LoadResult(loadAssemblyException, metadataFile);
+					debugInfoProvider = LoadDebugInfo(module);
 				}
 			}
-			catch (Exception)
+			else if (result.Package != null)
 			{
-				throw loadAssemblyException;
-			}
+				result.Package.LoadedAssembly = this;
 			}
-
-		LoadResult LoadAssembly(Stream stream, PEStreamOptions streamOptions, bool applyWinRTProjections)
-		{
-			MetadataReaderOptions options = applyWinRTProjections
-				? MetadataReaderOptions.ApplyWindowsRuntimeProjections
-				: MetadataReaderOptions.None;
-
-			PEFile module = new PEFile(fileName, stream, streamOptions, metadataOptions: options);
-
-			debugInfoProvider = LoadDebugInfo(module);
-			lock (loadedAssemblies)
+			else if (result.FileLoadException != null)
 			{
-				loadedAssemblies.Add(module, this);
-			}
-			return new LoadResult(module);
+				throw result.FileLoadException;
 			}
+			return result;
 
-		LoadResult LoadCompressedAssembly(string fileName)
-		{
-			const uint CompressedDataMagic = 0x5A4C4158; // Magic used for Xamarin compressed module header ('XALZ', little-endian)
-			using (var fileStream = new FileStream(fileName, FileMode.Open, FileAccess.Read))
-			using (var fileReader = new BinaryReader(fileStream))
+			async Task<Stream> PrepareStream()
 			{
-				// Read compressed file header
-				var magic = fileReader.ReadUInt32();
-				if (magic != CompressedDataMagic)
-					throw new InvalidDataException($"Xamarin compressed module header magic {magic} does not match expected {CompressedDataMagic}");
-				_ = fileReader.ReadUInt32(); // skip index into descriptor table, unused
-				int uncompressedLength = (int)fileReader.ReadUInt32();
-				int compressedLength = (int)fileStream.Length;  // Ensure we read all of compressed data
-				ArrayPool<byte> pool = ArrayPool<byte>.Shared;
-				var src = pool.Rent(compressedLength);
-				var dst = pool.Rent(uncompressedLength);
-				try
+				// runs on background thread
+				var stream = streamTask != null ? await streamTask.ConfigureAwait(false) : null;
+				if (stream != null)
 				{
-					// fileReader stream position is now at compressed module data
-					fileStream.Read(src, 0, compressedLength);
-					// Decompress
-					LZ4Codec.Decode(src, 0, compressedLength, dst, 0, uncompressedLength);
-					// Load module from decompressed data buffer
-					using (var uncompressedStream = new MemoryStream(dst, writable: false))
+					// Read the module from a precrafted stream
+					if (!stream.CanSeek)
 					{
-						return LoadAssembly(uncompressedStream, PEStreamOptions.PrefetchEntireImage, applyWinRTProjections);
+						var memoryStream = new MemoryStream();
+						stream.CopyTo(memoryStream);
+						stream.Close();
+						memoryStream.Position = 0;
+						stream = memoryStream;
 					}
+					return stream;
 				}
-				finally
+				else
 				{
-					pool.Return(dst);
-					pool.Return(src);
+					return new FileStream(fileName, FileMode.Open, FileAccess.Read);
 				}
 			}
 		}

ICSharpCode.ILSpyX/LoadedPackage.cs

@@ -71,8 +71,11 @@ namespace ICSharpCode.ILSpyX
 			foreach (var entry in this.Entries)
 			{
 				var (dirname, filename) = SplitName(entry.Name);
+				if (!string.IsNullOrEmpty(filename))
+				{
 					GetFolder(dirname).Entries.Add(new FolderEntry(filename, entry));
 				}
+			}
 			this.RootFolder = rootFolder;
 
 			static (string, string) SplitName(string filename)
@@ -336,6 +339,7 @@ namespace ICSharpCode.ILSpyX
 				{
 					asm = new LoadedAssembly(
 						package.LoadedAssembly, entry.Name,
+						fileLoaders: package.LoadedAssembly.AssemblyList.LoaderRegistry,
 						assemblyResolver: this,
 						stream: Task.Run(entry.TryOpenStream),
 						applyWinRTProjections: package.LoadedAssembly.AssemblyList.ApplyWinRTProjections,

ILSpy/Languages/CSharpLanguage.cs

@@ -518,7 +518,7 @@ namespace ICSharpCode.ILSpy
 			readonly DecompilationOptions options;
 
 			public ILSpyWholeProjectDecompiler(LoadedAssembly assembly, DecompilationOptions options)
-				: base(options.DecompilerSettings, assembly.GetAssemblyResolver(options.DecompilerSettings.AutoLoadAssemblyReferences, options.DecompilerSettings.ApplyWindowsRuntimeProjections), assembly.GetAssemblyReferenceClassifier(options.DecompilerSettings.ApplyWindowsRuntimeProjections), assembly.GetDebugInfoOrNull())
+				: base(options.DecompilerSettings, assembly.GetAssemblyResolver(options.DecompilerSettings.AutoLoadAssemblyReferences, options.DecompilerSettings.ApplyWindowsRuntimeProjections), null, assembly.GetAssemblyReferenceClassifier(options.DecompilerSettings.ApplyWindowsRuntimeProjections), assembly.GetDebugInfoOrNull())
 			{
 				this.assembly = assembly;
 				this.options = options;

ILSpy/MainWindow.xaml.cs

@@ -54,6 +54,7 @@ using ICSharpCode.ILSpy.TreeNodes;
 using ICSharpCode.ILSpy.Updates;
 using ICSharpCode.ILSpy.ViewModels;
 using ICSharpCode.ILSpyX;
+using ICSharpCode.ILSpyX.FileLoaders;
 using ICSharpCode.ILSpyX.Settings;
 using ICSharpCode.TreeView;
 
@@ -152,6 +153,7 @@ namespace ICSharpCode.ILSpy
 			InitMainMenu();
 			InitWindowMenu();
 			InitToolbar();
+			InitFileLoaders();
 			ContextMenuProvider.Add(AssemblyTreeView);
 
 			this.Loaded += MainWindow_Loaded;
@@ -579,6 +581,19 @@ namespace ICSharpCode.ILSpy
 		}
 		#endregion
 
+		#region File Loader extensibility
+
+		void InitFileLoaders()
+		{
+			// TODO
+			foreach (var loader in App.ExportProvider.GetExportedValues<IFileLoader>())
+			{
+
+			}
+		}
+
+		#endregion
+
 		#region Message Hook
 		protected override void OnSourceInitialized(EventArgs e)
 		{

ILSpy/TreeNodes/AssemblyTreeNode.cs

@@ -33,6 +33,7 @@ using ICSharpCode.ILSpy.Metadata;
 using ICSharpCode.ILSpy.Properties;
 using ICSharpCode.ILSpy.ViewModels;
 using ICSharpCode.ILSpyX;
+using ICSharpCode.ILSpyX.FileLoaders;
 using ICSharpCode.ILSpyX.PdbProvider;
 using ICSharpCode.TreeView;
 
@@ -188,7 +189,7 @@ namespace ICSharpCode.ILSpy.TreeNodes
 
 		protected override void LoadChildren()
 		{
-			LoadedAssembly.LoadResult loadResult;
+			LoadResult loadResult;
 			try
 			{
 				loadResult = LoadedAssembly.GetLoadResultAsync().GetAwaiter().GetResult();
@@ -205,7 +206,7 @@ namespace ICSharpCode.ILSpy.TreeNodes
 					switch (loadResult.MetadataFile.Kind)
 					{
 						case MetadataFile.MetadataFileKind.PortableExecutable:
-							LoadChildrenForPEFile(loadResult.PEFile);
+							LoadChildrenForPEFile(loadResult.MetadataFile);
 							break;
 						case MetadataFile.MetadataFileKind.WebCIL:
 							LoadChildrenForWebCilFile((WebCilFile)loadResult.MetadataFile);
@@ -462,7 +463,7 @@ namespace ICSharpCode.ILSpy.TreeNodes
 			try
 			{
 				var loadResult = LoadedAssembly.GetLoadResultAsync().GetAwaiter().GetResult();
-				if (loadResult.PEFile != null)
+				if (loadResult.MetadataFile != null)
 				{
 					language.DecompileAssembly(LoadedAssembly, output, options);
 				}
@@ -471,13 +472,9 @@ namespace ICSharpCode.ILSpy.TreeNodes
 					output.WriteLine("// " + LoadedAssembly.FileName);
 					DecompilePackage(loadResult.Package, output);
 				}
-				else if (loadResult.MetadataFile != null)
-				{
-					output.WriteLine("// " + LoadedAssembly.FileName);
-				}
-				else
+				else if (loadResult.FileLoadException != null)
 				{
-					LoadedAssembly.GetMetadataFileOrNullAsync().GetAwaiter().GetResult();
+					HandleException(loadResult.FileLoadException, loadResult.FileLoadException.Message);
 				}
 			}
 			catch (BadImageFormatException badImage)