Implement Visual Studio solution generation for icsharpcode#972

ICSharpCode.Decompiler/CSharp/SolutionCreator.cs

@@ -0,0 +1,275 @@
+// Copyright (c) 2016 Daniel Grunwald
+// 
+// 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;
+using System.IO;
+using System.Linq;
+using System.Xml.Linq;
+
+namespace ICSharpCode.Decompiler.CSharp
+{
+	/// <summary>
+	/// A container class that holds information about a Visual Studio project.
+	/// </summary>
+	public sealed class ProjectItem : ProjectId
+	{
+		/// <summary>
+		/// Initializes a new instance of the <see cref="ProjectItem"/> class.
+		/// </summary>
+		/// <param name="projectFile">The full path of the project file.</param>
+		/// <param name="projectPlatform">The project platform.</param>
+		/// <param name="projectGuid">The project GUID.</param>
+		/// 
+		/// <exception cref="ArgumentException">Thrown when <paramref name="projectFile"/> 
+		/// or <paramref name="projectPlatform"/> is null or empty.</exception>
+		public ProjectItem(string projectFile, string projectPlatform, Guid projectGuid)
+			: base(projectPlatform, projectGuid)
+		{
+			ProjectName = Path.GetFileNameWithoutExtension(projectFile);
+			FilePath = projectFile;
+		}
+
+		/// <summary>
+		/// Gets the name of the project.
+		/// </summary>
+		public string ProjectName { get; }
+
+		/// <summary>
+		/// Gets the full path to the project file.
+		/// </summary>
+		public string FilePath { get; }
+	}
+
+	/// <summary>
+	/// A container class that holds platform and GUID information about a Visual Studio project.
+	/// </summary>
+	public class ProjectId
+	{
+		/// <summary>
+		/// Initializes a new instance of the <see cref="ProjectId"/> class.
+		/// </summary>
+		/// <param name="projectPlatform">The project platform.</param>
+		/// <param name="projectGuid">The project GUID.</param>
+		/// 
+		/// <exception cref="ArgumentException">Thrown when <paramref name="projectFile"/> 
+		/// or <paramref name="projectPlatform"/> is null or empty.</exception>
+		public ProjectId(string projectPlatform, Guid projectGuid)
+		{
+			if (string.IsNullOrWhiteSpace(projectPlatform)) {
+				throw new ArgumentException("The platform cannot be null or empty.", nameof(projectPlatform));
+			}
+
+			Guid = projectGuid;
+			PlatformName = projectPlatform;
+		}
+
+		/// <summary>
+		/// Gets the GUID of this project.
+		/// </summary>
+		public Guid Guid { get; }
+
+		/// <summary>
+		/// Gets the platform name of this project. Only single platform per project is supported.
+		/// </summary>
+		public string PlatformName { get; }
+	}
+
+	/// <summary>
+	/// A helper class that can write a Visual Studio Solution file for the provided projects.
+	/// </summary>
+	public static class SolutionCreator
+	{
+		private static readonly XNamespace ProjectFileNamespace = XNamespace.Get("http://schemas.microsoft.com/developer/msbuild/2003");
+
+		/// <summary>
+		/// Writes a solution file to the specified <paramref name="targetFile"/>.
+		/// </summary>
+		/// <param name="targetFile">The full path of the file to write.</param>
+		/// <param name="projects">The projects contained in this solution.</param>
+		/// 
+		/// <exception cref="ArgumentException">Thrown when <paramref name="targetFile"/> is null or empty.</exception>
+		/// <exception cref="ArgumentNullException">Thrown when <paramref name="projects"/> is null.</exception>
+		/// <exception cref="InvalidOperationException">Thrown when <paramref name="projects"/> contains no items.</exception>
+		public static void WriteSolutionFile(string targetFile, IEnumerable<ProjectItem> projects)
+		{
+			if (string.IsNullOrWhiteSpace(targetFile)) {
+				throw new ArgumentException("The target file cannot be null or empty.", nameof(targetFile));
+			}
+
+			if (projects == null) {
+				throw new ArgumentNullException(nameof(projects));
+			}
+
+			if (!projects.Any()) {
+				throw new InvalidOperationException("At least one project is expected.");
+			}
+
+			using (var writer = new StreamWriter(targetFile)) {
+				WriteSolutionFile(writer, projects, Path.GetDirectoryName(targetFile));
+			}
+
+			FixProjectReferences(projects);
+		}
+
+		private static void WriteSolutionFile(TextWriter writer, IEnumerable<ProjectItem> projects, string solutionPath)
+		{
+			WriteHeader(writer);
+			WriteProjects(writer, projects, solutionPath);
+
+			writer.WriteLine("Global");
+
+			var platforms = WriteSolutionConfigurations(writer, projects);
+			WriteProjectConfigurations(writer, projects, platforms);
+
+			writer.WriteLine("\tGlobalSection(SolutionProperties) = preSolution");
+			writer.WriteLine("\t\tHideSolutionNode = FALSE");
+			writer.WriteLine("\tEndGlobalSection");
+
+			writer.WriteLine("EndGlobal");
+		}
+
+		private static void WriteHeader(TextWriter writer)
+		{
+			writer.WriteLine("Microsoft Visual Studio Solution File, Format Version 12.00");
+			writer.WriteLine("# Visual Studio 14");
+			writer.WriteLine("VisualStudioVersion = 14.0.24720.0");
+			writer.WriteLine("MinimumVisualStudioVersion = 10.0.40219.1");
+		}
+
+		private static void WriteProjects(TextWriter writer, IEnumerable<ProjectItem> projects, string solutionPath)
+		{
+			var solutionGuid = Guid.NewGuid().ToString("B").ToUpperInvariant();
+
+			foreach (var project in projects) {
+				var projectRelativePath = GetRelativePath(solutionPath, project.FilePath);
+				var projectGuid = project.Guid.ToString("B").ToUpperInvariant();
+
+				writer.WriteLine($"Project(\"{solutionGuid}\") = \"{project.ProjectName}\", \"{projectRelativePath}\", \"{projectGuid}\"");
+				writer.WriteLine("EndProject");
+			}
+		}
+
+		private static IEnumerable<string> WriteSolutionConfigurations(TextWriter writer, IEnumerable<ProjectItem> projects)
+		{
+			var platforms = projects.GroupBy(p => p.PlatformName).Select(g => g.Key).ToList();
+
+			platforms.Sort();
+
+			writer.WriteLine("\tGlobalSection(SolutionConfigurationPlatforms) = preSolution");
+			foreach (var platform in platforms) {
+				writer.WriteLine($"\t\tDebug|{platform} = Debug|{platform}");
+			}
+
+			foreach (var platform in platforms) {
+				writer.WriteLine($"\t\tRelease|{platform} = Release|{platform}");
+			}
+
+			writer.WriteLine("\tEndGlobalSection");
+
+			return platforms;
+		}
+
+		private static void WriteProjectConfigurations(
+			TextWriter writer,
+			IEnumerable<ProjectItem> projects,
+			IEnumerable<string> solutionPlatforms)
+		{
+			writer.WriteLine("\tGlobalSection(ProjectConfigurationPlatforms) = postSolution");
+
+			foreach (var project in projects) {
+				var projectGuid = project.Guid.ToString("B").ToUpperInvariant();
+
+				foreach (var platform in solutionPlatforms) {
+					writer.WriteLine($"\t\t{projectGuid}.Debug|{platform}.ActiveCfg = Debug|{project.PlatformName}");
+					writer.WriteLine($"\t\t{projectGuid}.Debug|{platform}.Build.0 = Debug|{project.PlatformName}");
+				}
+
+				foreach (var platform in solutionPlatforms) {
+					writer.WriteLine($"\t\t{projectGuid}.Release|{platform}.ActiveCfg = Release|{project.PlatformName}");
+					writer.WriteLine($"\t\t{projectGuid}.Release|{platform}.Build.0 = Release|{project.PlatformName}");
+				}
+			}
+
+			writer.WriteLine("\tEndGlobalSection");
+		}
+
+		private static void FixProjectReferences(IEnumerable<ProjectItem> projects)
+		{
+			var projectsMap = projects.ToDictionary(p => p.ProjectName, p => p);
+
+			foreach (var project in projects) {
+				var projectDirectory = Path.GetDirectoryName(project.FilePath);
+				XDocument projectDoc = XDocument.Load(project.FilePath);
+
+				var referencesItemGroups = projectDoc.Root
+					.Elements(ProjectFileNamespace + "ItemGroup")
+					.Where(e => e.Elements(ProjectFileNamespace + "Reference").Any());
+
+				foreach (var itemGroup in referencesItemGroups) {
+					FixProjectReferences(projectDirectory, itemGroup, projectsMap);
+				}
+
+				projectDoc.Save(project.FilePath);
+			}
+		}
+
+		private static void FixProjectReferences(string projectDirectory, XElement itemGroup, IDictionary<string, ProjectItem> projects)
+		{
+			foreach (var item in itemGroup.Elements(ProjectFileNamespace + "Reference").ToList()) {
+				var assemblyName = item.Attribute("Include")?.Value;
+				if (assemblyName != null && projects.TryGetValue(assemblyName, out var referencedProject)) {
+					item.Remove();
+
+					var projectReference = new XElement(ProjectFileNamespace + "ProjectReference",
+						new XElement(ProjectFileNamespace + "Project", referencedProject.Guid.ToString("B").ToUpperInvariant()),
+						new XElement(ProjectFileNamespace + "Name", referencedProject.ProjectName));
+					projectReference.SetAttributeValue("Include", GetRelativePath(projectDirectory, referencedProject.FilePath));
+
+					itemGroup.Add(projectReference);
+				}
+			}
+		}
+
+		private static string GetRelativePath(string fromPath, string toPath)
+		{
+			Uri fromUri = new Uri(AppendDirectorySeparatorChar(fromPath));
+			Uri toUri = new Uri(AppendDirectorySeparatorChar(toPath));
+
+			if (fromUri.Scheme != toUri.Scheme) {
+				return toPath;
+			}
+
+			Uri relativeUri = fromUri.MakeRelativeUri(toUri);
+			string relativePath = Uri.UnescapeDataString(relativeUri.ToString());
+
+			if (string.Equals(toUri.Scheme, Uri.UriSchemeFile, StringComparison.OrdinalIgnoreCase)) {
+				relativePath = relativePath.Replace(Path.AltDirectorySeparatorChar, Path.DirectorySeparatorChar);
+			}
+
+			return relativePath;
+		}
+
+		private static string AppendDirectorySeparatorChar(string path)
+		{
+			return Path.HasExtension(path) || path.EndsWith(Path.DirectorySeparatorChar.ToString())
+				? path
+				: path + Path.DirectorySeparatorChar;
+		}
+	}
+}

ICSharpCode.Decompiler/CSharp/WholeProjectDecompiler.cs

@@ -101,7 +101,7 @@ namespace ICSharpCode.Decompiler.CSharp
 			}
 		}
 
-		public void DecompileProject(PEFile moduleDefinition, string targetDirectory, TextWriter projectFileWriter, CancellationToken cancellationToken = default(CancellationToken))
+		public ProjectId DecompileProject(PEFile moduleDefinition, string targetDirectory, TextWriter projectFileWriter, CancellationToken cancellationToken = default(CancellationToken))
 		{
 			if (string.IsNullOrEmpty(targetDirectory)) {
 				throw new InvalidOperationException("Must set TargetDirectory");
@@ -110,7 +110,7 @@ namespace ICSharpCode.Decompiler.CSharp
 			directories.Clear();
 			var files = WriteCodeFilesInProject(moduleDefinition, cancellationToken).ToList();
 			files.AddRange(WriteResourceFilesInProject(moduleDefinition));
-			WriteProjectFile(projectFileWriter, files, moduleDefinition);
+			return WriteProjectFile(projectFileWriter, files, moduleDefinition);
 		}
 
 		enum LanguageTargets
@@ -120,11 +120,12 @@ namespace ICSharpCode.Decompiler.CSharp
 		}
 
 		#region WriteProjectFile
-		void WriteProjectFile(TextWriter writer, IEnumerable<Tuple<string, string>> files, Metadata.PEFile module)
+		ProjectId WriteProjectFile(TextWriter writer, IEnumerable<Tuple<string, string>> files, Metadata.PEFile module)
 		{
 			const string ns = "http://schemas.microsoft.com/developer/msbuild/2003";
 			string platformName = GetPlatformName(module);
 			Guid guid = this.ProjectGuid ?? Guid.NewGuid();
+
 			using (XmlTextWriter w = new XmlTextWriter(writer)) {
 				w.Formatting = Formatting.Indented;
 				w.WriteStartDocument();
@@ -281,6 +282,8 @@ namespace ICSharpCode.Decompiler.CSharp
 
 				w.WriteEndDocument();
 			}
+
+			return new ProjectId(platformName, guid);
 		}
 
 		protected virtual bool IsGacAssembly(Metadata.IAssemblyReference r, Metadata.PEFile asm)

ICSharpCode.Decompiler/ICSharpCode.Decompiler.csproj

@@ -61,6 +61,7 @@
     <Compile Include="CSharp\CSharpLanguageVersion.cs" />
     <Compile Include="CSharp\RequiredNamespaceCollector.cs" />
     <Compile Include="CSharp\SequencePointBuilder.cs" />
+    <Compile Include="CSharp\SolutionCreator.cs" />
     <Compile Include="CSharp\Syntax\AstNode.cs" />
     <Compile Include="CSharp\Syntax\AstNodeCollection.cs" />
     <Compile Include="CSharp\Syntax\AstType.cs" />

ILSpy/Languages/CSharpLanguage.cs

@@ -343,12 +343,12 @@ namespace ICSharpCode.ILSpy
 			}
 		}
 
-		public override void DecompileAssembly(LoadedAssembly assembly, ITextOutput output, DecompilationOptions options)
+		public override object DecompileAssembly(LoadedAssembly assembly, ITextOutput output, DecompilationOptions options)
 		{
 			var module = assembly.GetPEFileOrNull();
 			if (options.FullDecompilation && options.SaveAsProjectDirectory != null) {
 				var decompiler = new ILSpyWholeProjectDecompiler(assembly, options);
-				decompiler.DecompileProject(module, options.SaveAsProjectDirectory, new TextOutputWriter(output), options.CancellationToken);
+				return decompiler.DecompileProject(module, options.SaveAsProjectDirectory, new TextOutputWriter(output), options.CancellationToken);
 			} else {
 				AddReferenceAssemblyWarningMessage(module, output);
 				AddReferenceWarningMessage(module, output);
@@ -415,6 +415,8 @@ namespace ICSharpCode.ILSpy
 					}
 					WriteCode(output, options.DecompilerSettings, st, decompiler.TypeSystem);
 				}
+
+				return true;
 			}
 		}
 

ILSpy/Languages/ILLanguage.cs

@@ -150,7 +150,7 @@ namespace ICSharpCode.ILSpy
 			dis.DisassembleNamespace(nameSpace, module, types.Select(t => (TypeDefinitionHandle)t.MetadataToken));
 		}
 		
-		public override void DecompileAssembly(LoadedAssembly assembly, ITextOutput output, DecompilationOptions options)
+		public override object DecompileAssembly(LoadedAssembly assembly, ITextOutput output, DecompilationOptions options)
 		{
 			output.WriteLine("// " + assembly.FileName);
 			output.WriteLine();
@@ -174,6 +174,8 @@ namespace ICSharpCode.ILSpy
 					dis.WriteModuleContents(module);
 				}
 			}
+
+			return true;
 		}
 	}
 }

ILSpy/Languages/Language.cs

@@ -131,11 +131,11 @@ namespace ICSharpCode.ILSpy
 			WriteCommentLine(output, nameSpace);
 		}
 
-		public virtual void DecompileAssembly(LoadedAssembly assembly, ITextOutput output, DecompilationOptions options)
+		public virtual object DecompileAssembly(LoadedAssembly assembly, ITextOutput output, DecompilationOptions options)
 		{
 			WriteCommentLine(output, assembly.FileName);
 			var asm = assembly.GetPEFileOrNull();
-			if (asm == null) return;
+			if (asm == null) return false;
 			var metadata = asm.Metadata;
 			if (metadata.IsAssembly) {
 				var name = metadata.GetAssemblyDefinition();
@@ -147,6 +147,8 @@ namespace ICSharpCode.ILSpy
 			} else {
 				WriteCommentLine(output, metadata.GetString(metadata.GetModuleDefinition().Name));
 			}
+
+			return true;
 		}
 
 		public virtual void WriteCommentLine(ITextOutput output, string comment)

ILSpy/SolutionWriter.cs

@@ -27,6 +27,7 @@ using System.Threading;
 using System.Threading.Tasks;
 using System.Windows;
 using ICSharpCode.Decompiler;
+using ICSharpCode.Decompiler.CSharp;
 using ICSharpCode.ILSpy.TextView;
 using ICSharpCode.ILSpy.TreeNodes;
 using Microsoft.Win32;
@@ -130,6 +131,8 @@ namespace ICSharpCode.ILSpy
 		{
 			var solutionDirectory = Path.GetDirectoryName(solutionFilePath);
 			var statusOutput = new ConcurrentBag<string>();
+			var projects = new ConcurrentBag<ProjectItem>();
+
 			var result = new AvalonEditTextOutput();
 
 			var duplicates = new HashSet<string>();
@@ -140,20 +143,45 @@ namespace ICSharpCode.ILSpy
 
 			Stopwatch stopwatch = Stopwatch.StartNew();
 
-			await Task.Run(() => Parallel.ForEach(assemblyNodes, n => WriteProject(n, solutionDirectory, statusOutput, ct)))
+			try {
+				await Task.Run(() => Parallel.ForEach(assemblyNodes, n => WriteProject(n, solutionDirectory, statusOutput, projects, ct)))
 					.ConfigureAwait(false);
 
+				await Task.Run(() => SolutionCreator.WriteSolutionFile(solutionFilePath, projects))
+					.ConfigureAwait(false);
+			} catch (AggregateException ae) {
+				if (ae.Flatten().InnerExceptions.All(e => e is OperationCanceledException)) {
+					result.WriteLine();
+					result.WriteLine("Generation was cancelled.");
+					return result;
+				}
+
+				result.WriteLine();
+				result.WriteLine("Failed to generate the Visual Studio Solution. Errors:");
+				ae.Handle(e => {
+					result.WriteLine(e.Message);
+					return true;
+				});
+				
+				return result;
+			}
 
 			foreach (var item in statusOutput) {
 				result.WriteLine(item);
 			}
 
 			if (statusOutput.Count == 0) {
-				result.WriteLine("Successfully decompiled the following assemblies to a Visual Studio Solution:");
+				result.WriteLine("Successfully decompiled the following assemblies into Visual Studio projects:");
 				foreach (var item in assemblyNodes.Select(n => n.Text.ToString())) {
 					result.WriteLine(item);
 				}
 
+				result.WriteLine();
+
+				if (assemblyNodes.Count() == projects.Count) {
+					result.WriteLine("Created the Visual Studio Solution file.");
+				}
+
 				result.WriteLine();
 				result.WriteLine("Elapsed time: " + stopwatch.Elapsed.TotalSeconds.ToString("F1") + " seconds.");
 				result.WriteLine();
@@ -163,7 +191,12 @@ namespace ICSharpCode.ILSpy
 			return result;
 		}
 
-		private static void WriteProject(AssemblyTreeNode assemblyNode, string targetDirectory, ConcurrentBag<string> statusOutput, CancellationToken ct)
+		private static void WriteProject(
+			AssemblyTreeNode assemblyNode,
+			string targetDirectory,
+			ConcurrentBag<string> statusOutput,
+			ConcurrentBag<ProjectItem> targetContainer,
+			CancellationToken ct)
 		{
 			var loadedAssembly = assemblyNode.LoadedAssembly;
 
@@ -187,11 +220,16 @@ namespace ICSharpCode.ILSpy
 					CancellationToken = ct,
 					SaveAsProjectDirectory = targetDirectory };
 
-					assemblyNode.Decompile(assemblyNode.Language, projectFileOutput, options);
+					if (assemblyNode.Decompile(assemblyNode.Language, projectFileOutput, options) is ProjectId projectInfo) {
+						targetContainer.Add(new ProjectItem(projectFileName, projectInfo.PlatformName, projectInfo.Guid));
 					}
-			} catch (Exception e) {
+				}
+			} 
+			catch (OperationCanceledException) {
+				throw;
+			}
+			catch (Exception e) {
 				statusOutput.Add($"Failed to decompile the assembly '{loadedAssembly.FileName}':{Environment.NewLine}{e}");
-				return;
 			}
 		}
 	}

ILSpy/TreeNodes/AssemblyListTreeNode.cs

@@ -141,7 +141,7 @@ namespace ICSharpCode.ILSpy.TreeNodes
 
 		public Action<SharpTreeNode> Select = delegate { };
 
-		public override void Decompile(Language language, ITextOutput output, DecompilationOptions options)
+		public override object Decompile(Language language, ITextOutput output, DecompilationOptions options)
 		{
 			language.WriteCommentLine(output, "List: " + assemblyList.ListName);
 			output.WriteLine();
@@ -150,6 +150,8 @@ namespace ICSharpCode.ILSpy.TreeNodes
 				output.WriteLine();
 				asm.Decompile(language, output, options);
 			}
+
+			return true;
 		}
 
 		#region Find*Node

ILSpy/TreeNodes/AssemblyReferenceTreeNode.cs

@@ -79,7 +79,7 @@ namespace ICSharpCode.ILSpy.TreeNodes
 			}
 		}
 		
-		public override void Decompile(Language language, ITextOutput output, DecompilationOptions options)
+		public override object Decompile(Language language, ITextOutput output, DecompilationOptions options)
 		{
 			var loaded = parentAssembly.LoadedAssembly.LoadedAssemblyReferencesInfo.TryGetInfo(r.FullName, out var info);
 			if (r.IsWindowsRuntime) {
@@ -98,6 +98,8 @@ namespace ICSharpCode.ILSpy.TreeNodes
 				output.Unindent();
 				output.WriteLine();
 			}
+
+			return true;
 		}
 	}
 }

ILSpy/TreeNodes/AssemblyTreeNode.cs

@@ -240,7 +240,7 @@ namespace ICSharpCode.ILSpy.TreeNodes
 				return FilterResult.Recurse;
 		}
 
-		public override void Decompile(Language language, ITextOutput output, DecompilationOptions options)
+		public override object Decompile(Language language, ITextOutput output, DecompilationOptions options)
 		{
 			void HandleException(Exception ex, string message)
 			{
@@ -259,21 +259,21 @@ namespace ICSharpCode.ILSpy.TreeNodes
 				switch (ex.InnerException) {
 					case BadImageFormatException badImage:
 						HandleException(badImage, "This file does not contain a managed assembly.");
-						return;
+						return null;
 					case FileNotFoundException fileNotFound:
 						HandleException(fileNotFound, "The file was not found.");
-						return;
+						return null;
 					case DirectoryNotFoundException dirNotFound:
 						HandleException(dirNotFound, "The directory was not found.");
-						return;
+						return null;
 					case PEFileNotSupportedException notSupported:
 						HandleException(notSupported, notSupported.Message);
-						return;
+						return null;
 					default:
 						throw;
 				}
 			}
-			language.DecompileAssembly(LoadedAssembly, output, options);
+			return language.DecompileAssembly(LoadedAssembly, output, options);
 		}
 
 		public override bool Save(DecompilerTextView textView)

ILSpy/TreeNodes/BaseTypesEntryNode.cs

@@ -97,9 +97,10 @@ namespace ICSharpCode.ILSpy.TreeNodes
 			return false;
 		}
 
-		public override void Decompile(Language language, ITextOutput output, DecompilationOptions options)
+		public override object Decompile(Language language, ITextOutput output, DecompilationOptions options)
 		{
 			language.WriteCommentLine(output, language.TypeToString(type, includeNamespace: true));
+			return true;
 		}
 
 		IEntity IMemberTreeNode.Member {

ILSpy/TreeNodes/BaseTypesTreeNode.cs

@@ -69,12 +69,14 @@ namespace ICSharpCode.ILSpy.TreeNodes
 			}
 		}
 
-		public override void Decompile(Language language, ITextOutput output, DecompilationOptions options)
+		public override object Decompile(Language language, ITextOutput output, DecompilationOptions options)
 		{
 			App.Current.Dispatcher.Invoke(DispatcherPriority.Normal, new Action(EnsureLazyChildren));
 			foreach (ILSpyTreeNode child in this.Children) {
 				child.Decompile(language, output, options);
 			}
+
+			return true;
 		}
 	}
 }

ILSpy/TreeNodes/DerivedTypesEntryNode.cs

@@ -90,9 +90,10 @@ namespace ICSharpCode.ILSpy.TreeNodes
 			e.Handled = BaseTypesEntryNode.ActivateItem(this, type);
 		}
 
-		public override void Decompile(Language language, ITextOutput output, DecompilationOptions options)
+		public override object Decompile(Language language, ITextOutput output, DecompilationOptions options)
 		{
 			language.WriteCommentLine(output, language.TypeToString(type, includeNamespace: true));
+			return true;
 		}
 
 		IEntity IMemberTreeNode.Member => type;

ILSpy/TreeNodes/DerivedTypesTreeNode.cs

@@ -92,9 +92,10 @@ namespace ICSharpCode.ILSpy.TreeNodes
 			return typeRef.GetFullTypeName(referenceMetadata) == typeDef.GetFullTypeName(definitionMetadata);
 		}
 
-		public override void Decompile(Language language, ITextOutput output, DecompilationOptions options)
+		public override object Decompile(Language language, ITextOutput output, DecompilationOptions options)
 		{
 			threading.Decompile(language, output, options, EnsureLazyChildren);
+			return true;
 		}
 	}
 }

ILSpy/TreeNodes/EventTreeNode.cs

@@ -67,9 +67,10 @@ namespace ICSharpCode.ILSpy.TreeNodes
 				return FilterResult.Hidden;
 		}
 		
-		public override void Decompile(Language language, ITextOutput output, DecompilationOptions options)
+		public override object Decompile(Language language, ITextOutput output, DecompilationOptions options)
 		{
 			language.DecompileEvent(EventDefinition, output, options);
+			return true;
 		}
 		
 		public override bool IsPublicAPI {

ILSpy/TreeNodes/FieldTreeNode.cs

@@ -68,9 +68,10 @@ namespace ICSharpCode.ILSpy.TreeNodes
 				return FilterResult.Hidden;
 		}
 
-		public override void Decompile(Language language, ITextOutput output, DecompilationOptions options)
+		public override object Decompile(Language language, ITextOutput output, DecompilationOptions options)
 		{
 			language.DecompileField(FieldDefinition, output, options);
+			return true;
 		}
 		
 		public override bool IsPublicAPI {

ILSpy/TreeNodes/ILSpyTreeNode.cs

@@ -57,7 +57,7 @@ namespace ICSharpCode.ILSpy.TreeNodes
 				return FilterResult.Hidden;
 		}
 
-		public abstract void Decompile(Language language, ITextOutput output, DecompilationOptions options);
+		public abstract object Decompile(Language language, ITextOutput output, DecompilationOptions options);
 
 		/// <summary>
 		/// Used to implement special view logic for some items.

ILSpy/TreeNodes/MethodTreeNode.cs

@@ -83,9 +83,10 @@ namespace ICSharpCode.ILSpy.TreeNodes
 			}
 		}
 
-		public override void Decompile(Language language, ITextOutput output, DecompilationOptions options)
+		public override object Decompile(Language language, ITextOutput output, DecompilationOptions options)
 		{
 			language.DecompileMethod(MethodDefinition, output, options);
+			return true;
 		}
 
 		public override FilterResult Filter(FilterSettings settings)

ILSpy/TreeNodes/ModuleReferenceTreeNode.cs

@@ -72,10 +72,11 @@ namespace ICSharpCode.ILSpy.TreeNodes
 			}
 		}
 
-		public override void Decompile(Language language, ITextOutput output, DecompilationOptions options)
+		public override object Decompile(Language language, ITextOutput output, DecompilationOptions options)
 		{
 			language.WriteCommentLine(output, moduleName);
 			language.WriteCommentLine(output, containsMetadata ? "contains metadata" : "contains no metadata");
+			return true;
 		}
 	}
 }

ILSpy/TreeNodes/NamespaceTreeNode.cs

@@ -56,9 +56,10 @@ namespace ICSharpCode.ILSpy.TreeNodes
 				return FilterResult.Recurse;
 		}
 		
-		public override void Decompile(Language language, ITextOutput output, DecompilationOptions options)
+		public override object Decompile(Language language, ITextOutput output, DecompilationOptions options)
 		{
 			language.DecompileNamespace(name, this.Children.OfType<TypeTreeNode>().Select(t => t.TypeDefinition), output, options);
+			return true;
 		}
 	}
 }

ILSpy/TreeNodes/PropertyTreeNode.cs

@@ -74,9 +74,10 @@ namespace ICSharpCode.ILSpy.TreeNodes
 				return FilterResult.Hidden;
 		}
 
-		public override void Decompile(Language language, ITextOutput output, DecompilationOptions options)
+		public override object Decompile(Language language, ITextOutput output, DecompilationOptions options)
 		{
 			language.DecompileProperty(PropertyDefinition, output, options);
+			return true;
 		}
 
 		public override bool IsPublicAPI {

ILSpy/TreeNodes/ReferenceFolderTreeNode.cs

@@ -62,7 +62,7 @@ namespace ICSharpCode.ILSpy.TreeNodes
 				this.Children.Add(new ModuleReferenceTreeNode(parentAssembly, r, metadata));
 		}
 		
-		public override void Decompile(Language language, ITextOutput output, DecompilationOptions options)
+		public override object Decompile(Language language, ITextOutput output, DecompilationOptions options)
 		{
 			language.WriteCommentLine(output, $"Detected Target-Framework-Id: {parentAssembly.LoadedAssembly.GetTargetFrameworkIdAsync().Result}");
 			App.Current.Dispatcher.Invoke(DispatcherPriority.Normal, new Action(EnsureLazyChildren));
@@ -86,7 +86,7 @@ namespace ICSharpCode.ILSpy.TreeNodes
 				output.Unindent();
 				output.WriteLine();
 			}
-			
+			return true;
 		}
 	}
 }

ILSpy/TreeNodes/ResourceListTreeNode.cs

@@ -64,13 +64,15 @@ namespace ICSharpCode.ILSpy.TreeNodes
 				return FilterResult.Recurse;
 		}
 		
-		public override void Decompile(Language language, ITextOutput output, DecompilationOptions options)
+		public override object Decompile(Language language, ITextOutput output, DecompilationOptions options)
 		{
 			App.Current.Dispatcher.Invoke(DispatcherPriority.Normal, new Action(EnsureLazyChildren));
 			foreach (ILSpyTreeNode child in this.Children) {
 				child.Decompile(language, output, options);
 				output.WriteLine();
 			}
+
+			return true;
 		}
 	}
 }

ILSpy/TreeNodes/ResourceNodes/ImageListResourceEntryNode.cs

@@ -75,9 +75,10 @@ namespace ICSharpCode.ILSpy.TreeNodes
 		}
 
 
-		public override void Decompile(Language language, ITextOutput output, DecompilationOptions options)
+		public override object Decompile(Language language, ITextOutput output, DecompilationOptions options)
 		{
 			EnsureLazyChildren();
+			return true;
 		}
 	}
 }

ILSpy/TreeNodes/ResourceNodes/ResourceEntryNode.cs

@@ -73,9 +73,10 @@ namespace ICSharpCode.ILSpy.TreeNodes
 			return result;
 		}
 
-		public override void Decompile(Language language, ITextOutput output, DecompilationOptions options)
+		public override object Decompile(Language language, ITextOutput output, DecompilationOptions options)
 		{
 			language.WriteCommentLine(output, string.Format("{0} = {1}", key, data));
+			return true;
 		}
 
 		public override bool Save(DecompilerTextView textView)

ILSpy/TreeNodes/ResourceNodes/ResourceTreeNode.cs

@@ -67,7 +67,7 @@ namespace ICSharpCode.ILSpy.TreeNodes
 				return FilterResult.Hidden;
 		}
 		
-		public override void Decompile(Language language, ITextOutput output, DecompilationOptions options)
+		public override object Decompile(Language language, ITextOutput output, DecompilationOptions options)
 		{
 			language.WriteCommentLine(output, string.Format("{0} ({1}, {2})", r.Name, r.ResourceType, r.Attributes));
 			
@@ -76,6 +76,8 @@ namespace ICSharpCode.ILSpy.TreeNodes
 				smartOutput.AddButton(Images.Save, Resources.Save, delegate { Save(MainWindow.Instance.TextView); });
 				output.WriteLine();
 			}
+
+			return true;
 		}
 		
 		public override bool View(DecompilerTextView textView)

ILSpy/TreeNodes/ResourceNodes/ResourcesFileTreeNode.cs

@@ -141,7 +141,7 @@ namespace ICSharpCode.ILSpy.TreeNodes
 			return true;
 		}
 
-		public override void Decompile(Language language, ITextOutput output, DecompilationOptions options)
+		public override object Decompile(Language language, ITextOutput output, DecompilationOptions options)
 		{
 			EnsureLazyChildren();
 			base.Decompile(language, output, options);
@@ -168,6 +168,8 @@ namespace ICSharpCode.ILSpy.TreeNodes
 				}
 				output.WriteLine();
 			}
+
+			return true;
 		}
 
 		internal class SerializedObjectRepresentation

ILSpy/TreeNodes/ThreadingSupport.cs

@@ -128,8 +128,9 @@ namespace ICSharpCode.ILSpy.TreeNodes
 				return FilterResult.Match;
 			}
 			
-			public override void Decompile(Language language, ITextOutput output, DecompilationOptions options)
+			public override object Decompile(Language language, ITextOutput output, DecompilationOptions options)
 			{
+				return false;
 			}
 		}
 		
@@ -151,8 +152,9 @@ namespace ICSharpCode.ILSpy.TreeNodes
 				return FilterResult.Match;
 			}
 			
-			public override void Decompile(Language language, ITextOutput output, DecompilationOptions options)
+			public override object Decompile(Language language, ITextOutput output, DecompilationOptions options)
 			{
+				return false;
 			}
 		}
 

ILSpy/TreeNodes/TypeTreeNode.cs

@@ -103,9 +103,10 @@ namespace ICSharpCode.ILSpy.TreeNodes
 
 		public override bool CanExpandRecursively => true;
 
-		public override void Decompile(Language language, ITextOutput output, DecompilationOptions options)
+		public override object Decompile(Language language, ITextOutput output, DecompilationOptions options)
 		{
 			language.DecompileType(TypeDefinition, output, options);
+			return true;
 		}
 
 		public override object Icon => GetIcon(TypeDefinition);