- Replace DecompilerTextView.CleanUpName with direct uses of WholeProjectDecompiler.CleanUpFileName

- Add file extension handling to WholeProjectDecompiler.CleanUpName
- Add WholeProjectDecompiler.SanitizeFileName, which respects file extensions

ICSharpCode.Decompiler/CSharp/ProjectDecompiler/WholeProjectDecompiler.cs

@@ -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))
@@ -571,14 +571,25 @@ 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 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 +598,49 @@ namespace ICSharpCode.Decompiler.CSharp.ProjectDecompiler
 			if (pos > 0)
 				text = text.Substring(0, pos);
 			text = text.Trim();
-			// Whitelist allowed characters, replace everything else:
+			string extension = null;
-			StringBuilder b = new StringBuilder(text.Length);
 			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
@@ -614,7 +651,7 @@ namespace ICSharpCode.Decompiler.CSharp.ProjectDecompiler
 				}
 				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 +662,8 @@ 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 +677,8 @@ namespace ICSharpCode.Decompiler.CSharp.ProjectDecompiler
 		/// </summary>
 		public static string CleanUpDirectoryName(string text)
 		{
-			return CleanUpFileName(text, separateAtDots: true).Replace('.', Path.DirectorySeparatorChar);
+			return CleanUpName(text, separateAtDots: true, treatAsFileName: false)
+				.Replace('.', Path.DirectorySeparatorChar);
 		}
 
 		static bool IsReservedFileSystemName(string name)

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/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)
 			{