Merge pull request #199 from gui-cs/tig/tig-extract-automatic-folding-orchestrat

Extract automatic folding orchestration from Ted into Editor

Author: tig

examples/ted/TedApp.FileOperations.cs

@@ -586,7 +586,6 @@ private void ApplyFileMetadata (string? filePath)
 
         UpdateFileNameShortcut ();
         UpdatePreviewVisibility ();
-        InstallFolding ();
         Editor.SetNeedsDraw ();
     }
 

examples/ted/TedApp.cs

@@ -22,17 +22,11 @@ namespace Ted;
 /// </summary>
 public sealed partial class TedApp : Window
 {
-    private const int MaximumAutomaticFoldingDocumentLength = 1_000_000;
-
-    private readonly BraceFoldingStrategy _braceFoldingStrategy;
-
     // Per-instance config path. Defaults to the real ~/.tui location; tests inject a temp path so they
     // never touch the developer's real config (and stay parallel-safe — no env/static mutation).
     private readonly string _configPath;
     private readonly Shortcut _fileNameShortcut;
     private readonly MenuItem _previewMarkdownMenuItem;
-    private TextDocument? _foldingDocument;
-    private bool _foldingUpdateNeeded;
 
     /// <summary>Initializes a new <see cref="TedApp" />.</summary>
     /// <param name="readOnly">Opens the editor read-only.</param>
@@ -78,9 +72,8 @@ public TedApp (bool readOnly = false, string? configPath = null)
         Editor.IndentationStrategy =
             EditorSettings.AutoIndent ? new DefaultIndentationStrategy () : null;
 
-        // Enable brace-based folding. The strategy re-scans on each document change.
-        _braceFoldingStrategy = new BraceFoldingStrategy ();
-        InstallFolding ();
+        // Enable brace-based folding. The editor handles the full lifecycle automatically.
+        Editor.FoldingStrategy = new BraceFoldingStrategy ();
 
         ShowOpenDialog = ShowDefaultOpenDialog;
         ShowSaveDialog = ShowDefaultSaveDialog;
@@ -573,259 +566,4 @@ private void ShowSettingsDialog ()
 
         dialog.Dispose ();
     }
-
-    /// <summary>
-    ///     Creates a <see cref="FoldingManager" /> for the current document and wires up
-    ///     automatic fold updates on document changes.
-    /// </summary>
-    private void InstallFolding ()
-    {
-        if (Editor.Document is null)
-        {
-            SetFoldingDocument (null);
-
-            return;
-        }
-
-        if (Editor.Document.TextLength > MaximumAutomaticFoldingDocumentLength)
-        {
-            SetFoldingDocument (null);
-            Editor.FoldingManager = null;
-
-            return;
-        }
-
-        FoldingManager fm = new (Editor.Document);
-        Editor.FoldingManager = fm;
-        _braceFoldingStrategy.UpdateFoldings (fm, Editor.Document);
-        SetFoldingDocument (Editor.Document);
-    }
-
-    private void UpdateFoldings ()
-    {
-        if (Editor.FoldingManager is null || Editor.Document is null)
-        {
-            return;
-        }
-
-        if (Editor.Document.TextLength > MaximumAutomaticFoldingDocumentLength)
-        {
-            SetFoldingDocument (null);
-            Editor.FoldingManager = null;
-
-            return;
-        }
-
-        _braceFoldingStrategy.UpdateFoldings (Editor.FoldingManager,
-            Editor.Document);
-    }
-
-    private void SetFoldingDocument (TextDocument? document)
-    {
-        if (ReferenceEquals (_foldingDocument, document))
-        {
-            return;
-        }
-
-        if (_foldingDocument is not null)
-        {
-            _foldingDocument.Changed -= OnFoldingDocumentChanged;
-            _foldingDocument.UpdateFinished -= OnFoldingDocumentUpdateFinished;
-        }
-
-        _foldingDocument = document;
-        _foldingUpdateNeeded = false;
-
-        if (_foldingDocument is not null)
-        {
-            _foldingDocument.Changed += OnFoldingDocumentChanged;
-            _foldingDocument.UpdateFinished += OnFoldingDocumentUpdateFinished;
-        }
-    }
-
-    private void OnFoldingDocumentChanged (object? sender, DocumentChangeEventArgs e)
-    {
-        _foldingUpdateNeeded |= FoldingChangeMayAffectStructure (e);
-    }
-
-    private void OnFoldingDocumentUpdateFinished (object? sender, EventArgs e)
-    {
-        if (!_foldingUpdateNeeded)
-        {
-            return;
-        }
-
-        _foldingUpdateNeeded = false;
-        UpdateFoldings ();
-    }
-
-    private bool FoldingChangeMayAffectStructure (DocumentChangeEventArgs e)
-    {
-        if (TryGetMappedStructuralChange (e, out var mappedStructuralChange))
-        {
-            return mappedStructuralChange;
-        }
-
-        return ContainsFoldingStructuralCharacter (e.InsertedText)
-               || ContainsFoldingStructuralCharacter (e.RemovedText);
-    }
-
-    private bool TryGetMappedStructuralChange (DocumentChangeEventArgs e, out bool structuralChange)
-    {
-        structuralChange = false;
-        OffsetChangeMap map = e.OffsetChangeMap;
-        var hasInsertion = false;
-        var hasRemoval = false;
-
-        if (map.Count == 0)
-        {
-            return false;
-        }
-
-        foreach (OffsetChangeMapEntry entry in map)
-        {
-            hasInsertion |= entry.InsertionLength > 0;
-            hasRemoval |= entry.RemovalLength > 0;
-
-            if (entry.InsertionLength > 0 && entry.RemovalLength > 0)
-            {
-                return false;
-            }
-        }
-
-        if (!hasInsertion && !hasRemoval)
-        {
-            return false;
-        }
-
-        if (hasInsertion && hasRemoval)
-        {
-            return false;
-        }
-
-        structuralChange = hasInsertion
-            ? MappedInsertionsContainFoldingStructuralCharacter (map, e.InsertedText, e.Offset)
-            : MappedRemovalsContainFoldingStructuralCharacter (map, e.RemovedText, e.Offset, e.RemovalLength);
-
-        return true;
-    }
-
-    private bool MappedInsertionsContainFoldingStructuralCharacter (OffsetChangeMap map, ITextSource text,
-        int baseOffset)
-    {
-        if (InsertionEntriesUseInsertedTextCoordinates (map, baseOffset, text.TextLength))
-        {
-            return MappedInsertionsContainFoldingStructuralCharacterWithoutShift (map, text, baseOffset);
-        }
-
-        var insertedShift = 0;
-
-        foreach (OffsetChangeMapEntry entry in map)
-        {
-            if (entry.InsertionLength == 0)
-            {
-                continue;
-            }
-
-            var relativeOffset = entry.Offset - baseOffset + insertedShift;
-
-            if (ContainsFoldingStructuralCharacter (text, relativeOffset, entry.InsertionLength))
-            {
-                return true;
-            }
-
-            insertedShift += entry.InsertionLength;
-        }
-
-        return false;
-    }
-
-    private bool MappedInsertionsContainFoldingStructuralCharacterWithoutShift (
-        OffsetChangeMap map,
-        ITextSource text,
-        int baseOffset)
-    {
-        foreach (OffsetChangeMapEntry entry in map)
-        {
-            if (entry.InsertionLength == 0)
-            {
-                continue;
-            }
-
-            var relativeOffset = entry.Offset - baseOffset;
-
-            if (ContainsFoldingStructuralCharacter (text, relativeOffset, entry.InsertionLength))
-            {
-                return true;
-            }
-        }
-
-        return false;
-    }
-
-    private bool MappedRemovalsContainFoldingStructuralCharacter (
-        OffsetChangeMap map,
-        ITextSource text,
-        int baseOffset,
-        int removalLength)
-    {
-        if (!RemovalEntriesUseRemovedTextCoordinates (map, baseOffset, removalLength))
-        {
-            return MappedInsertionsContainFoldingStructuralCharacter (map.Invert (), text, baseOffset);
-        }
-
-        foreach (OffsetChangeMapEntry entry in map)
-        {
-            if (entry.RemovalLength == 0)
-            {
-                continue;
-            }
-
-            var relativeOffset = entry.Offset - baseOffset;
-
-            if (ContainsFoldingStructuralCharacter (text, relativeOffset, entry.RemovalLength))
-            {
-                return true;
-            }
-        }
-
-        return false;
-    }
-
-    private static bool RemovalEntriesUseRemovedTextCoordinates (OffsetChangeMap map, int baseOffset, int removalLength)
-    {
-        return map.Count > 0
-               && map[0].RemovalLength > 0
-               && map[0].Offset + map[0].RemovalLength == baseOffset + removalLength;
-    }
-
-    private static bool InsertionEntriesUseInsertedTextCoordinates (OffsetChangeMap map, int baseOffset,
-        int insertionLength)
-    {
-        return map.Count > 0
-               && map[^1].InsertionLength > 0
-               && map[^1].Offset + map[^1].InsertionLength == baseOffset + insertionLength;
-    }
-
-    private bool ContainsFoldingStructuralCharacter (ITextSource text)
-    {
-        return ContainsFoldingStructuralCharacter (text, 0, text.TextLength);
-    }
-
-    private bool ContainsFoldingStructuralCharacter (ITextSource text, int offset, int length)
-    {
-        for (var i = offset; i < offset + length; i++)
-        {
-            var ch = text.GetCharAt (i);
-
-            if (ch == _braceFoldingStrategy.OpeningBrace
-                || ch == _braceFoldingStrategy.ClosingBrace
-                || ch is '\r' or '\n')
-            {
-                return true;
-            }
-        }
-
-        return false;
-    }
 }