Merge pull request #2567 from icsharpcode/filename-sanitizer

Improve file name sanitizer

ICSharpCode.Decompiler.Tests/TestCases/PdbGen/ForLoopTests.xml

@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="utf-8"?>
 <symbols>
   <files>
-    <file id="1" name="ICSharpCode\Decompiler\Tests\TestCases\PdbGen\ForLoopTests.cs" language="C#" checksumAlgorithm="SHA256"><![CDATA[using System;
+    <file id="1" name="ICSharpCode.Decompiler.Tests.TestCases.PdbGen\ForLoopTests.cs" language="C#" checksumAlgorithm="SHA256"><![CDATA[using System;
 
 namespace ICSharpCode.Decompiler.Tests.TestCases.PdbGen;
 

ICSharpCode.Decompiler.Tests/TestCases/PdbGen/HelloWorld.xml

@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="utf-8"?>
 <symbols>
   <files>
-    <file id="1" name="ICSharpCode\Decompiler\Tests\TestCases\PdbGen\HelloWorld.cs" language="C#" checksumAlgorithm="SHA256"><![CDATA[using System;
+    <file id="1" name="ICSharpCode.Decompiler.Tests.TestCases.PdbGen\HelloWorld.cs" language="C#" checksumAlgorithm="SHA256"><![CDATA[using System;
 
 namespace ICSharpCode.Decompiler.Tests.TestCases.PdbGen;
 

ICSharpCode.Decompiler.Tests/TestCases/PdbGen/LambdaCapturing.xml

@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="utf-8"?>
 <symbols>
   <files>
-    <file id="1" name="ICSharpCode\Decompiler\Tests\TestCases\PdbGen\LambdaCapturing.cs" language="C#" checksumAlgorithm="SHA256"><![CDATA[using System;
+    <file id="1" name="ICSharpCode.Decompiler.Tests.TestCases.PdbGen\LambdaCapturing.cs" language="C#" checksumAlgorithm="SHA256"><![CDATA[using System;
 
 namespace ICSharpCode.Decompiler.Tests.TestCases.PdbGen;
 

ICSharpCode.Decompiler/CSharp/ProjectDecompiler/WholeProjectDecompiler.cs

@@ -214,7 +214,7 @@ namespace ICSharpCode.Decompiler.CSharp.ProjectDecompiler
 					}
 					else
 					{
-						string dir = CleanUpDirectoryName(ns);
+						string dir = Settings.UseNestedDirectoriesForNamespaces ? CleanUpPath(ns) : CleanUpDirectoryName(ns);
 						if (directories.Add(dir))
 							Directory.CreateDirectory(Path.Combine(TargetDirectory, dir));
 						return Path.Combine(dir, file);
@@ -269,7 +269,7 @@ namespace ICSharpCode.Decompiler.CSharp.ProjectDecompiler
 						{
 							foreach (var (name, value) in resourcesFile)
 							{
-								string fileName = CleanUpFileName(name)
+								string fileName = SanitizeFileName(name)
 									.Replace('/', Path.DirectorySeparatorChar);
 								string dirName = Path.GetDirectoryName(fileName);
 								if (!string.IsNullOrEmpty(dirName) && directories.Add(dirName))
@@ -279,7 +279,7 @@ namespace ICSharpCode.Decompiler.CSharp.ProjectDecompiler
 								Stream entryStream = (Stream)value;
 								entryStream.Position = 0;
 								individualResources.AddRange(
-									WriteResourceToFile(fileName, (string)name, entryStream));
+									WriteResourceToFile(fileName, name, entryStream));
 							}
 							decodedIntoIndividualFiles = true;
 						}
@@ -368,6 +368,7 @@ namespace ICSharpCode.Decompiler.CSharp.ProjectDecompiler
 			// That is, a full name of the form "Namespace1.Namespace2{...}.NamespaceN.ResourceName" is split such that
 			// the directory part Namespace1\Namespace2\... reuses as many existing directories as
 			// possible, and only the remaining name parts are used as prefix for the filename.
+			// This is not affected by the UseNestedDirectoriesForNamespaces setting.
 			string[] splitName = fullName.Split(Path.DirectorySeparatorChar);
 			string fileName = string.Join(".", splitName);
 			string separator = Path.DirectorySeparatorChar.ToString();
@@ -546,7 +547,7 @@ namespace ICSharpCode.Decompiler.CSharp.ProjectDecompiler
 				{
 					case PlatformID.MacOSX:
 					case PlatformID.Unix:
-						return (true, int.MaxValue, int.MaxValue);
+						return (true, int.MaxValue, 255);
 					case PlatformID.Win32NT:
 						const string key = @"SYSTEM\CurrentControlSet\Control\FileSystem";
 						var fileSystem = Registry.LocalMachine.OpenSubKey(key);
@@ -571,14 +572,25 @@ namespace ICSharpCode.Decompiler.CSharp.ProjectDecompiler
 		/// </summary>
 		public static string CleanUpFileName(string text)
 		{
-			return CleanUpFileName(text, separateAtDots: false);
+			return CleanUpName(text, separateAtDots: false, treatAsFileName: false);
+		}
+
+		/// <summary>
+		/// Removes invalid characters from file names and reduces their length,
+		/// but keeps file extensions and path structure intact.
+		/// </summary>
+		public static string SanitizeFileName(string fileName)
+		{
+			return CleanUpName(fileName, separateAtDots: false, treatAsFileName: true);
 		}
 
 		/// <summary>
 		/// Cleans up a node name for use as a file system name. If <paramref name="separateAtDots"/> is active,
-		/// dots are seen as segment separators. Each segment is limited to 255 characters.
+		/// dots are seen as segment separators. Each segment is limited to maxSegmentLength characters.
+		/// (see <see cref="GetLongPathSupport"/>) If <paramref name="treatAsFileName"/> is active,
+		/// we check for file a extension and try to preserve it, if it's valid.
 		/// </summary>
-		static string CleanUpFileName(string text, bool separateAtDots)
+		static string CleanUpName(string text, bool separateAtDots, bool treatAsFileName)
 		{
 			int pos = text.IndexOf(':');
 			if (pos > 0)
@@ -587,23 +599,49 @@ namespace ICSharpCode.Decompiler.CSharp.ProjectDecompiler
 			if (pos > 0)
 				text = text.Substring(0, pos);
 			text = text.Trim();
-			// Whitelist allowed characters, replace everything else:
-			StringBuilder b = new StringBuilder(text.Length);
+			string extension = null;
 			int currentSegmentLength = 0;
 			var (supportsLongPaths, maxPathLength, maxSegmentLength) = longPathSupport.Value;
+			if (treatAsFileName)
+			{
+				// Check if input is a file name, i.e., has a valid extension
+				// If yes, preserve extension and append it at the end.
+				// But only, if the extension length does not exceed maxSegmentLength,
+				// if that's the case we just give up and treat the extension no different
+				// from the file name.
+				int lastDot = text.LastIndexOf('.');
+				if (lastDot >= 0 && text.Length - lastDot < maxSegmentLength)
+				{
+					string originalText = text;
+					extension = text.Substring(lastDot);
+					text = text.Remove(lastDot);
+					foreach (var c in extension)
+					{
+						if (!(char.IsLetterOrDigit(c) || c == '-' || c == '_' || c == '.'))
+						{
+							// extension contains an invalid character, therefore cannot be a valid extension.
+							extension = null;
+							text = originalText;
+							break;
+						}
+					}
+				}
+			}
+			// Whitelist allowed characters, replace everything else:
+			StringBuilder b = new StringBuilder(text.Length + (extension?.Length ?? 0));
 			foreach (var c in text)
 			{
 				currentSegmentLength++;
 				if (char.IsLetterOrDigit(c) || c == '-' || c == '_')
 				{
-					// if the current segment exceeds 255 characters,
+					// if the current segment exceeds maxSegmentLength characters,
 					// skip until the end of the segment.
 					if (currentSegmentLength <= maxSegmentLength)
 						b.Append(c);
 				}
 				else if (c == '.' && b.Length > 0 && b[b.Length - 1] != '.')
 				{
-					// if the current segment exceeds 255 characters,
+					// if the current segment exceeds maxSegmentLength characters,
 					// skip until the end of the segment.
 					if (separateAtDots || currentSegmentLength <= maxSegmentLength)
 						b.Append('.'); // allow dot, but never two in a row
@@ -612,9 +650,15 @@ namespace ICSharpCode.Decompiler.CSharp.ProjectDecompiler
 					if (separateAtDots)
 						currentSegmentLength = 0;
 				}
+				else if (treatAsFileName && (c == '/' || c == '\\') && currentSegmentLength > 0)
+				{
+					// if we treat this as a file name, we've started a new segment
+					b.Append(c);
+					currentSegmentLength = 0;
+				}
 				else
 				{
-					// if the current segment exceeds 255 characters,
+					// if the current segment exceeds maxSegmentLength characters,
 					// skip until the end of the segment.
 					if (currentSegmentLength <= maxSegmentLength)
 						b.Append('-');
@@ -625,6 +669,8 @@ namespace ICSharpCode.Decompiler.CSharp.ProjectDecompiler
 			if (b.Length == 0)
 				b.Append('-');
 			string name = b.ToString();
+			if (extension != null)
+				name += extension;
 			if (IsReservedFileSystemName(name))
 				return name + "_";
 			else if (name == ".")
@@ -638,7 +684,13 @@ namespace ICSharpCode.Decompiler.CSharp.ProjectDecompiler
 		/// </summary>
 		public static string CleanUpDirectoryName(string text)
 		{
-			return CleanUpFileName(text, separateAtDots: true).Replace('.', Path.DirectorySeparatorChar);
+			return CleanUpName(text, separateAtDots: false, treatAsFileName: false);
+		}
+
+		public static string CleanUpPath(string text)
+		{
+			return CleanUpName(text, separateAtDots: true, treatAsFileName: false)
+				.Replace('.', Path.DirectorySeparatorChar);
 		}
 
 		static bool IsReservedFileSystemName(string name)

ICSharpCode.Decompiler/DebugInfo/PortablePdbWriter.cs

@@ -66,7 +66,10 @@ namespace ICSharpCode.Decompiler.DebugInfo
 			string BuildFileNameFromTypeName(TypeDefinitionHandle handle)
 			{
 				var typeName = handle.GetFullTypeName(reader).TopLevelTypeName;
-				return Path.Combine(WholeProjectDecompiler.CleanUpDirectoryName(typeName.Namespace), WholeProjectDecompiler.CleanUpFileName(typeName.Name) + ".cs");
+				string ns = settings.UseNestedDirectoriesForNamespaces
+					? WholeProjectDecompiler.CleanUpPath(typeName.Namespace)
+					: WholeProjectDecompiler.CleanUpDirectoryName(typeName.Namespace);
+				return Path.Combine(ns, WholeProjectDecompiler.CleanUpFileName(typeName.Name) + ".cs");
 			}
 
 			foreach (var sourceFile in reader.GetTopLevelTypeDefinitions().GroupBy(BuildFileNameFromTypeName))

ICSharpCode.Decompiler/DecompilerSettings.cs

@@ -1777,7 +1777,7 @@ namespace ICSharpCode.Decompiler
 		/// Gets or sets a value indicating whether the new SDK style format
 		/// shall be used for the generated project files.
 		/// </summary>
-		[Category("DecompilerSettings.Other")]
+		[Category("DecompilerSettings.ProjectExport")]
 		[Description("DecompilerSettings.UseSdkStyleProjectFormat")]
 		public bool UseSdkStyleProjectFormat {
 			get { return useSdkStyleProjectFormat; }
@@ -1790,6 +1790,25 @@ namespace ICSharpCode.Decompiler
 			}
 		}
 
+		bool useNestedDirectoriesForNamespaces;
+
+		/// <summary>
+		/// Gets/sets whether namespaces and namespace-like identifiers should be split at '.'
+		/// and each part should produce a new level of nesting in the output directory structure. 
+		/// </summary>
+		[Category("DecompilerSettings.ProjectExport")]
+		[Description("DecompilerSettings.UseNestedDirectoriesForNamespaces")]
+		public bool UseNestedDirectoriesForNamespaces {
+			get { return useNestedDirectoriesForNamespaces; }
+			set {
+				if (useNestedDirectoriesForNamespaces != value)
+				{
+					useNestedDirectoriesForNamespaces = value;
+					OnPropertyChanged();
+				}
+			}
+		}
+
 		bool aggressiveScalarReplacementOfAggregates = false;
 
 		[Category("DecompilerSettings.Other")]

ILSpy/Commands/ExtractPackageEntryContextMenuEntry.cs

@@ -23,6 +23,7 @@ using System.Linq;
 using System.Threading.Tasks;
 
 using ICSharpCode.Decompiler;
+using ICSharpCode.Decompiler.CSharp.ProjectDecompiler;
 using ICSharpCode.ILSpy.Properties;
 using ICSharpCode.ILSpy.TextView;
 using ICSharpCode.ILSpy.TreeNodes;
@@ -46,7 +47,7 @@ namespace ICSharpCode.ILSpy
 				return;
 			var assembly = selectedNodes[0].PackageEntry;
 			SaveFileDialog dlg = new SaveFileDialog();
-			dlg.FileName = Path.GetFileName(DecompilerTextView.CleanUpName(assembly.Name));
+			dlg.FileName = Path.GetFileName(WholeProjectDecompiler.SanitizeFileName(assembly.Name));
 			dlg.Filter = ".NET assemblies|*.dll;*.exe;*.winmd" + Resources.AllFiles;
 			dlg.InitialDirectory = Path.GetDirectoryName(bundleNode.LoadedAssembly.FileName);
 			if (dlg.ShowDialog() != true)
@@ -70,7 +71,7 @@ namespace ICSharpCode.ILSpy
 				{
 					foreach (var node in selectedNodes)
 					{
-						var fileName = Path.GetFileName(DecompilerTextView.CleanUpName(node.PackageEntry.Name));
+						var fileName = Path.GetFileName(WholeProjectDecompiler.SanitizeFileName(node.PackageEntry.Name));
 						SaveEntry(output, node.PackageEntry, Path.Combine(outputFolderOrFileName, fileName));
 					}
 				}

ILSpy/Commands/GeneratePdbContextMenuEntry.cs

@@ -25,6 +25,7 @@ using System.Windows;
 
 using ICSharpCode.Decompiler;
 using ICSharpCode.Decompiler.CSharp;
+using ICSharpCode.Decompiler.CSharp.ProjectDecompiler;
 using ICSharpCode.Decompiler.DebugInfo;
 using ICSharpCode.ILSpy.Properties;
 using ICSharpCode.ILSpy.TextView;
@@ -63,7 +64,7 @@ namespace ICSharpCode.ILSpy
 				return;
 			}
 			SaveFileDialog dlg = new SaveFileDialog();
-			dlg.FileName = DecompilerTextView.CleanUpName(assembly.ShortName) + ".pdb";
+			dlg.FileName = WholeProjectDecompiler.CleanUpFileName(assembly.ShortName) + ".pdb";
 			dlg.Filter = Resources.PortablePDBPdbAllFiles;
 			dlg.InitialDirectory = Path.GetDirectoryName(assembly.FileName);
 			if (dlg.ShowDialog() != true)

ILSpy/Commands/SelectPdbContextMenuEntry.cs

@@ -19,8 +19,8 @@
 using System.IO;
 using System.Linq;
 
+using ICSharpCode.Decompiler.CSharp.ProjectDecompiler;
 using ICSharpCode.ILSpy.Properties;
-using ICSharpCode.ILSpy.TextView;
 using ICSharpCode.ILSpy.TreeNodes;
 
 using Microsoft.Win32;
@@ -35,7 +35,7 @@ namespace ICSharpCode.ILSpy
 			if (assembly == null)
 				return;
 			OpenFileDialog dlg = new OpenFileDialog();
-			dlg.FileName = DecompilerTextView.CleanUpName(assembly.ShortName) + ".pdb";
+			dlg.FileName = WholeProjectDecompiler.CleanUpFileName(assembly.ShortName) + ".pdb";
 			dlg.Filter = Resources.PortablePDBPdbAllFiles;
 			dlg.InitialDirectory = Path.GetDirectoryName(assembly.FileName);
 			if (dlg.ShowDialog() != true)

ILSpy/Options/MiscSettingsPanel.xaml

@@ -6,9 +6,13 @@
 			 xmlns:properties="clr-namespace:ICSharpCode.ILSpy.Properties"
 			 mc:Ignorable="d" 
              d:DesignHeight="300" d:DesignWidth="300">
-	<StackPanel Margin="10">
-		<CheckBox IsChecked="{Binding AllowMultipleInstances}" Content="{x:Static properties:Resources.AllowMultipleInstances}" />
-		<CheckBox IsChecked="{Binding LoadPreviousAssemblies}" Content="{x:Static properties:Resources.LoadAssembliesThatWereLoadedInTheLastInstance}"/>
-		<Button Command="{Binding AddRemoveShellIntegrationCommand}" Content="{Binding AddRemoveShellIntegrationText}" Margin="3" />
+	<StackPanel Orientation="Vertical">
+		<GroupBox Header="{x:Static properties:Resources.Misc}">
+			<StackPanel Margin="10">
+				<CheckBox IsChecked="{Binding AllowMultipleInstances}" Content="{x:Static properties:Resources.AllowMultipleInstances}" />
+				<CheckBox IsChecked="{Binding LoadPreviousAssemblies}" Content="{x:Static properties:Resources.LoadAssembliesThatWereLoadedInTheLastInstance}"/>
+				<Button Command="{Binding AddRemoveShellIntegrationCommand}" Content="{Binding AddRemoveShellIntegrationText}" Margin="3" />
+			</StackPanel>
+		</GroupBox>
 	</StackPanel>
 </UserControl>

ILSpy/Options/MiscSettingsPanel.xaml.cs

@@ -49,7 +49,7 @@ namespace ICSharpCode.ILSpy.Options
 		{
 			XElement e = settings["MiscSettings"];
 			var s = new MiscSettings();
-			s.AllowMultipleInstances = (bool?)e.Attribute("AllowMultipleInstances") ?? false;
+			s.AllowMultipleInstances = (bool?)e.Attribute(nameof(s.AllowMultipleInstances)) ?? false;
 			s.LoadPreviousAssemblies = (bool?)e.Attribute(nameof(s.LoadPreviousAssemblies)) ?? true;
 
 			return s;
@@ -60,7 +60,7 @@ namespace ICSharpCode.ILSpy.Options
 			var s = (MiscSettings)this.DataContext;
 
 			var section = new XElement("MiscSettings");
-			section.SetAttributeValue("AllowMultipleInstances", s.AllowMultipleInstances);
+			section.SetAttributeValue(nameof(s.AllowMultipleInstances), s.AllowMultipleInstances);
 			section.SetAttributeValue(nameof(s.LoadPreviousAssemblies), s.LoadPreviousAssemblies);
 
 			XElement existingElement = root.Element("MiscSettings");

ILSpy/Properties/Resources.Designer.cs

@@ -1127,6 +1127,15 @@ namespace ICSharpCode.ILSpy.Properties {
             }
         }
         
+        /// <summary>
+        ///   Looks up a localized string similar to Project export.
+        /// </summary>
+        public static string DecompilerSettings_ProjectExport {
+            get {
+                return ResourceManager.GetString("DecompilerSettings.ProjectExport", resourceCulture);
+            }
+        }
+        
         /// <summary>
         ///   Looks up a localized string similar to Ranges.
         /// </summary>
@@ -1316,6 +1325,15 @@ namespace ICSharpCode.ILSpy.Properties {
             }
         }
         
+        /// <summary>
+        ///   Looks up a localized string similar to Use nested directories for namespaces.
+        /// </summary>
+        public static string DecompilerSettings_UseNestedDirectoriesForNamespaces {
+            get {
+                return ResourceManager.GetString("DecompilerSettings.UseNestedDirectoriesForNamespaces", resourceCulture);
+            }
+        }
+        
         /// <summary>
         ///   Looks up a localized string similar to Use non-trailing named arguments.
         /// </summary>
@@ -2002,7 +2020,7 @@ namespace ICSharpCode.ILSpy.Properties {
         }
         
         /// <summary>
-        ///   Looks up a localized string similar to You can change this by toggling the setting at Options &gt; Decompiler &gt; Other &gt; Use new SDK style format for generated project files (*.csproj)..
+        ///   Looks up a localized string similar to You can change this by toggling the setting at Options &gt; Decompiler &gt; Project export &gt; Use new SDK style format for generated project files (*.csproj)..
         /// </summary>
         public static string ProjectExportFormatChangeSettingHint {
             get {
@@ -2029,9 +2047,11 @@ namespace ICSharpCode.ILSpy.Properties {
         }
         
         /// <summary>
-        ///   Looks up a localized string similar to Failed to decompile the assemblies {0} because the namespace directory structure is nested too deep.
+        ///   Looks up a localized string similar to Failed to decompile the assemblies {0} because the namespace names are too long or the directory structure is nested too deep.
+        ///
+        ///If you are using Windows 10.0.14393 (Windows 10 version 1607) or later, you can enable &quot;Long path support&quot; by creating a REG_DWORD registry key named &quot;LongPathsEnabled&quot; with value 0x1 at &quot;HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\FileSystem&quot; (see https://docs.microsoft.com/en-us/windows/win32/fileio/maximum-file-path-limitation for more information).
         ///
-        ///If you are using Windows 10.0.14393 (Windows 10 version 1607) or later, you can enable &quot;Long path support&quot; by creating a REG_DWORD registry key named &quot;LongPathsEnabled&quot; with value 0x1 at &quot;HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\FileSystem&quot; (see https://docs.microsoft.com/en-us/windows/win32/fileio/maximum-file-path-limitation for more information)..
+        ///If this does not [rest of string was truncated]&quot;;.
         /// </summary>
         public static string ProjectExportPathTooLong {
             get {

ILSpy/Properties/Resources.resx

@@ -399,6 +399,9 @@ Are you sure you want to continue?</value>
   <data name="DecompilerSettings.PatternMatching" xml:space="preserve">
     <value>Use pattern matching expressions</value>
   </data>
+  <data name="DecompilerSettings.ProjectExport" xml:space="preserve">
+    <value>Project export</value>
+  </data>
   <data name="DecompilerSettings.Ranges" xml:space="preserve">
     <value>Ranges</value>
   </data>
@@ -462,6 +465,9 @@ Are you sure you want to continue?</value>
   <data name="DecompilerSettings.UseNamedArguments" xml:space="preserve">
     <value>Use named arguments</value>
   </data>
+  <data name="DecompilerSettings.UseNestedDirectoriesForNamespaces" xml:space="preserve">
+    <value>Use nested directories for namespaces</value>
+  </data>
   <data name="DecompilerSettings.UseNonTrailingNamedArguments" xml:space="preserve">
     <value>Use non-trailing named arguments</value>
   </data>
@@ -689,7 +695,7 @@ Please disable all filters that might hide the item (i.e. activate "View &gt; Sh
     <value>Portable PDB|*.pdb|All files|*.*</value>
   </data>
   <data name="ProjectExportFormatChangeSettingHint" xml:space="preserve">
-    <value>You can change this by toggling the setting at Options &gt; Decompiler &gt; Other &gt; Use new SDK style format for generated project files (*.csproj).</value>
+    <value>You can change this by toggling the setting at Options &gt; Decompiler &gt; Project export &gt; Use new SDK style format for generated project files (*.csproj).</value>
   </data>
   <data name="ProjectExportFormatNonSDKHint" xml:space="preserve">
     <value>A Non-SDK project was generated. Learn more at https://docs.microsoft.com/en-us/nuget/resources/check-project-format.</value>
@@ -698,9 +704,11 @@ Please disable all filters that might hide the item (i.e. activate "View &gt; Sh
     <value>A SDK-style project was generated. Learn more at https://docs.microsoft.com/en-us/nuget/resources/check-project-format.</value>
   </data>
   <data name="ProjectExportPathTooLong" xml:space="preserve">
-    <value>Failed to decompile the assemblies {0} because the namespace directory structure is nested too deep.
+    <value>Failed to decompile the assemblies {0} because the namespace names are too long or the directory structure is nested too deep.
+
+If you are using Windows 10.0.14393 (Windows 10 version 1607) or later, you can enable "Long path support" by creating a REG_DWORD registry key named "LongPathsEnabled" with value 0x1 at "HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\FileSystem" (see https://docs.microsoft.com/en-us/windows/win32/fileio/maximum-file-path-limitation for more information).
 
-If you are using Windows 10.0.14393 (Windows 10 version 1607) or later, you can enable "Long path support" by creating a REG_DWORD registry key named "LongPathsEnabled" with value 0x1 at "HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\FileSystem" (see https://docs.microsoft.com/en-us/windows/win32/fileio/maximum-file-path-limitation for more information).</value>
+If this does not solve the problem and your system supports long paths, you can try to use a nested path structure. You can change this by toggling the setting at Options &gt; Decompiler &gt; Project export &gt; Use nested directories for namespaces. This helps because even on "long-path-aware" platforms, the length of a directory name is limited, on Windows/NTFS this is 255 characters.</value>
   </data>
   <data name="PropertyManuallyMissingReferencesListLoadedAssemblies" xml:space="preserve">
     <value>for ex. property getter/setter access. To get optimal decompilation results, please manually add the missing references to the list of loaded assemblies.</value>

ILSpy/TextView/DecompilerTextView.cs

@@ -1034,7 +1034,7 @@ namespace ICSharpCode.ILSpy.TextView
 			SaveFileDialog dlg = new SaveFileDialog();
 			dlg.DefaultExt = language.FileExtension;
 			dlg.Filter = language.Name + "|*" + language.FileExtension + Properties.Resources.AllFiles;
-			dlg.FileName = CleanUpName(treeNodes.First().ToString()) + language.FileExtension;
+			dlg.FileName = WholeProjectDecompiler.CleanUpFileName(treeNodes.First().ToString()) + language.FileExtension;
 			if (dlg.ShowDialog() == true)
 			{
 				SaveToDisk(new DecompilationContext(language, treeNodes.ToArray(), options), dlg.FileName);
@@ -1149,14 +1149,6 @@ namespace ICSharpCode.ILSpy.TextView
 			thread.Start();
 			return tcs.Task;
 		}
-
-		/// <summary>
-		/// Cleans up a node name for use as a file name.
-		/// </summary>
-		internal static string CleanUpName(string text)
-		{
-			return WholeProjectDecompiler.CleanUpFileName(text);
-		}
 		#endregion
 
 		internal ReferenceSegment? GetReferenceSegmentAtMousePosition()

ILSpy/TreeNodes/AssemblyTreeNode.cs

@@ -26,10 +26,10 @@ using System.Windows.Controls;
 using System.Windows.Documents;
 
 using ICSharpCode.Decompiler;
+using ICSharpCode.Decompiler.CSharp.ProjectDecompiler;
 using ICSharpCode.Decompiler.Metadata;
 using ICSharpCode.Decompiler.TypeSystem;
 using ICSharpCode.ILSpy.Properties;
-using ICSharpCode.ILSpy.TextView;
 using ICSharpCode.ILSpy.ViewModels;
 using ICSharpCode.TreeView;
 
@@ -384,7 +384,7 @@ namespace ICSharpCode.ILSpy.TreeNodes
 			if (string.IsNullOrEmpty(language.ProjectFileExtension))
 				return false;
 			SaveFileDialog dlg = new SaveFileDialog();
-			dlg.FileName = DecompilerTextView.CleanUpName(LoadedAssembly.ShortName) + language.ProjectFileExtension;
+			dlg.FileName = WholeProjectDecompiler.CleanUpFileName(LoadedAssembly.ShortName) + language.ProjectFileExtension;
 			dlg.Filter = language.Name + " project|*" + language.ProjectFileExtension + "|" + language.Name + " single file|*" + language.FileExtension + "|All files|*.*";
 			if (dlg.ShowDialog() == true)
 			{

ILSpy/TreeNodes/ResourceNodes/ResourceEntryNode.cs

@@ -20,8 +20,8 @@ using System;
 using System.IO;
 
 using ICSharpCode.Decompiler;
+using ICSharpCode.Decompiler.CSharp.ProjectDecompiler;
 using ICSharpCode.Decompiler.Metadata;
-using ICSharpCode.ILSpy.TextView;
 
 using Microsoft.Win32;
 
@@ -80,7 +80,7 @@ namespace ICSharpCode.ILSpy.TreeNodes
 		public override bool Save(ViewModels.TabPageModel tabPage)
 		{
 			SaveFileDialog dlg = new SaveFileDialog();
-			dlg.FileName = Path.GetFileName(DecompilerTextView.CleanUpName(key));
+			dlg.FileName = Path.GetFileName(WholeProjectDecompiler.SanitizeFileName(key));
 			if (dlg.ShowDialog() == true)
 			{
 				using var data = OpenStream();

ILSpy/TreeNodes/ResourceNodes/ResourceTreeNode.cs

@@ -24,6 +24,7 @@ using System.Text;
 using ICSharpCode.AvalonEdit.Highlighting;
 using ICSharpCode.AvalonEdit.Utils;
 using ICSharpCode.Decompiler;
+using ICSharpCode.Decompiler.CSharp.ProjectDecompiler;
 using ICSharpCode.Decompiler.Metadata;
 using ICSharpCode.ILSpy.Properties;
 using ICSharpCode.ILSpy.TextView;
@@ -91,7 +92,7 @@ namespace ICSharpCode.ILSpy.TreeNodes
 					if (type == FileType.Xml)
 						ext = ".xml";
 					else
-						ext = Path.GetExtension(DecompilerTextView.CleanUpName(Resource.Name));
+						ext = Path.GetExtension(WholeProjectDecompiler.SanitizeFileName(Resource.Name));
 					tabPage.ShowTextView(textView => textView.ShowNode(output, this, HighlightingManager.Instance.GetDefinitionByExtension(ext)));
 					tabPage.SupportsLanguageSwitching = false;
 					return true;
@@ -106,7 +107,7 @@ namespace ICSharpCode.ILSpy.TreeNodes
 			if (s == null)
 				return false;
 			SaveFileDialog dlg = new SaveFileDialog();
-			dlg.FileName = DecompilerTextView.CleanUpName(Resource.Name);
+			dlg.FileName = Path.GetFileName(WholeProjectDecompiler.SanitizeFileName(Resource.Name));
 			if (dlg.ShowDialog() == true)
 			{
 				s.Position = 0;

ILSpy/TreeNodes/ResourceNodes/ResourcesFileTreeNode.cs

@@ -24,6 +24,7 @@ using System.IO;
 using System.Linq;
 
 using ICSharpCode.Decompiler;
+using ICSharpCode.Decompiler.CSharp.ProjectDecompiler;
 using ICSharpCode.Decompiler.Metadata;
 using ICSharpCode.Decompiler.Util;
 using ICSharpCode.ILSpy.Controls;
@@ -129,7 +130,7 @@ namespace ICSharpCode.ILSpy.TreeNodes
 			if (s == null)
 				return false;
 			SaveFileDialog dlg = new SaveFileDialog();
-			dlg.FileName = DecompilerTextView.CleanUpName(Resource.Name);
+			dlg.FileName = Path.GetFileName(WholeProjectDecompiler.SanitizeFileName(Resource.Name));
 			dlg.Filter = Resources.ResourcesFileFilter;
 			if (dlg.ShowDialog() == true)
 			{