editable - refactoring of tabs processing

src/dlangui/core/editable.d

@@ -402,20 +402,42 @@ alias TokenPropString = ubyte[];
 
 /// interface for custom syntax highlight
 interface SyntaxHighlighter {
+
+    /// returns editable content
+    @property EditableContent content();
+    /// set editable content
+    @property SyntaxHighlighter content(EditableContent content);
+
     /// categorize characters in content by token types
     void updateHighlight(dstring[] lines, TokenPropString[] props, int changeStartLine, int changeEndLine);
     /// return true if toggle line comment is supported for file type
     @property bool supportsToggleLineComment();
     /// return true if can toggle line comments for specified text range
-    bool canToggleLineComment(EditableContent content, TextRange range);
+    bool canToggleLineComment(TextRange range);
     /// toggle line comments for specified text range
-    void toggleLineComment(EditableContent content, TextRange range, Object source);
+    void toggleLineComment(TextRange range, Object source);
     /// return true if toggle block comment is supported for file type
     @property bool supportsToggleBlockComment();
     /// return true if can toggle block comments for specified text range
-    bool canToggleBlockComment(EditableContent content, TextRange range);
+    bool canToggleBlockComment(TextRange range);
     /// toggle block comments for specified text range
-    void toggleBlockComment(EditableContent content, TextRange range, Object source);
+    void toggleBlockComment(TextRange range, Object source);
+}
+
+/// measure line text (tabs, spaces, and nonspace positions)
+struct TextLineMeasure {
+    /// line length
+    int len;
+    /// first non-space index in line
+    int firstNonSpace = -1;
+    /// first non-space position according to tab size
+    int firstNonSpaceX;
+    /// last non-space character index in line
+    int lastNonSpace = -1;
+    /// last non-space position based on tab size
+    int lastNonSpaceX;
+    /// true if line has zero length or consists of spaces and tabs only
+    @property bool empty() { return len == 0 || firstNonSpace < 0; }
 }
 
 /// editable plain text (singleline/multiline)
@@ -442,6 +464,7 @@ class EditableContent {
 
     @property EditableContent syntaxHighlighter(SyntaxHighlighter syntaxHighlighter) {
         _syntaxHighlighter = syntaxHighlighter;
+        _syntaxHighlighter.content = this;
         updateTokenProps(0, cast(int)_lines.length);
         return this;
     }
@@ -461,6 +484,31 @@ class EditableContent {
         _readOnly = readOnly;
     }
 
+    protected int _tabSize = 4;
+    protected bool _useSpacesForTabs = true;
+    /// returns tab size (in number of spaces)
+    @property int tabSize() {
+        return _tabSize;
+    }
+    /// sets tab size (in number of spaces)
+    @property EditableContent tabSize(int newTabSize) {
+        if (newTabSize < 1)
+            newTabSize = 1;
+        else if (newTabSize > 16)
+            newTabSize = 16;
+        _tabSize = newTabSize;
+        return this;
+    }
+    /// when true, spaces will be inserted instead of tabs
+    @property bool useSpacesForTabs() {
+        return _useSpacesForTabs;
+    }
+    /// set new Tab key behavior flag: when true, spaces will be inserted instead of tabs
+    @property EditableContent useSpacesForTabs(bool useSpacesForTabs) {
+        _useSpacesForTabs = useSpacesForTabs;
+        return this;
+    }
+
 	/// listeners for edit operations
 	Signal!EditableContentListener contentChangeListeners;
 
@@ -622,6 +670,52 @@ class EditableContent {
         return TextRange(TextPosition(lineIndex, 0), lineIndex < _lines.length - 1 ? lineBegin(lineIndex + 1) : lineEnd(lineIndex));
 	}
 
+    /// measures line non-space start and end positions
+    TextLineMeasure measureLine(int lineIndex) {
+        TextLineMeasure res;
+        dstring s = _lines[lineIndex];
+        res.len = cast(int)s.length;
+        if (lineIndex < 0 || lineIndex >= _lines.length)
+            return res;
+        int x = 0;
+        for (int i = 0; i < s.length; i++) {
+            dchar ch = s[i];
+            if (ch == ' ') {
+                x++;
+            } else if (ch == '\t') {
+                x = (x + _tabSize) % _tabSize;
+            } else {
+                if (res.firstNonSpace < 0) {
+                    res.firstNonSpace = i;
+                    res.firstNonSpaceX = x;
+                }
+                res.lastNonSpace = i;
+                res.lastNonSpaceX = x;
+                x++;
+            }
+        }
+        return res;
+    }
+
+    /// return true if line with index lineIndex is empty (has length 0 or consists only of spaces and tabs)
+    bool lineIsEmpty(int lineIndex) {
+        if (lineIndex < 0 || lineIndex >= _lines.length)
+            return true;
+        dstring s = _lines[lineIndex];
+        foreach(ch; s)
+            if (ch != ' ' && ch != '\t')
+                return false;
+        return true;
+    }
+
+    /// corrent range to cover full lines
+    TextRange fullLinesRange(TextRange r) {
+        r.start.pos = 0;
+        if (r.end.pos > 0)
+            r.end = lineBegin(r.end.line + 1);
+        return r;
+    }
+
     /// returns position before first non-space character of line, returns 0 position if no non-space chars
     TextPosition firstNonSpace(int lineIndex) {
         dstring s = line(lineIndex);

src/dlangui/widgets/editors.d

@@ -180,14 +180,12 @@ class EditWidgetBase : ScrollWidgetBase, EditableContentListener, MenuItemAction
     protected Point _scrollPos;
     protected bool _fixedFont;
     protected int _spaceWidth;
-    protected int _tabSize = 4;
     protected int _leftPaneWidth; // left pane - can be used to show line numbers, collapse controls, bookmarks, breakpoints, custom icons
 
     protected int _minFontSize = -1; // disable zooming
     protected int _maxFontSize = -1; // disable zooming
 
     protected bool _wantTabs = true;
-    protected bool _useSpacesForTabs = false;
     protected bool _showLineNumbers = false; // show line numbers in left pane
     protected bool _showModificationMarks = false; // show modification marks in left pane
     protected bool _showIcons = false; // show icons in left pane
@@ -564,18 +562,18 @@ class EditWidgetBase : ScrollWidgetBase, EditableContentListener, MenuItemAction
 
     /// when true, spaces will be inserted instead of tabs
     @property bool useSpacesForTabs() {
-        return _useSpacesForTabs;
+        return _content.useSpacesForTabs;
     }
 
     /// set new Tab key behavior flag: when true, spaces will be inserted instead of tabs
     @property EditWidgetBase useSpacesForTabs(bool useSpacesForTabs) {
-        _useSpacesForTabs = useSpacesForTabs;
+        _content.useSpacesForTabs = useSpacesForTabs;
         return this;
     }
 
     /// returns tab size (in number of spaces)
     @property int tabSize() {
-        return _tabSize;
+        return _content.tabSize;
     }
 
     /// sets tab size (in number of spaces)
@@ -584,8 +582,8 @@ class EditWidgetBase : ScrollWidgetBase, EditableContentListener, MenuItemAction
             newTabSize = 1;
         else if (newTabSize > 16)
             newTabSize = 16;
-        if (newTabSize != _tabSize) {
+        if (newTabSize != tabSize) {
-            _tabSize = newTabSize;
+            _content.tabSize = newTabSize;
             requestLayout();
         }
         return this;
@@ -807,7 +805,7 @@ class EditWidgetBase : ScrollWidgetBase, EditableContentListener, MenuItemAction
     protected int calcLineWidth(dstring s) {
         int w = 0;
         if (_fixedFont) {
-            int tabw = _tabSize * _spaceWidth;
+            int tabw = tabSize * _spaceWidth;
             // version optimized for fixed font
             for (int i = 0; i < s.length; i++) {
                 if (s[i] == '\t') {
@@ -910,7 +908,7 @@ class EditWidgetBase : ScrollWidgetBase, EditableContentListener, MenuItemAction
 			case EditorActions.ToggleBlockComment:
                 if (!_content.syntaxHighlighter || !_content.syntaxHighlighter.supportsToggleBlockComment)
                     a.state = ACTION_STATE_INVISIBLE;
-                else if (_content.syntaxHighlighter.canToggleBlockComment(_content, _selectionRange))
+                else if (_content.syntaxHighlighter.canToggleBlockComment(_selectionRange))
                     a.state = ACTION_STATE_ENABLED;
                 else
                     a.state = ACTION_STATE_DISABLE;
@@ -918,7 +916,7 @@ class EditWidgetBase : ScrollWidgetBase, EditableContentListener, MenuItemAction
 			case EditorActions.ToggleLineComment:
                 if (!_content.syntaxHighlighter || !_content.syntaxHighlighter.supportsToggleLineComment)
                     a.state = ACTION_STATE_INVISIBLE;
-                else if (_content.syntaxHighlighter.canToggleLineComment(_content, _selectionRange))
+                else if (_content.syntaxHighlighter.canToggleLineComment(_selectionRange))
                     a.state = ACTION_STATE_ENABLED;
                 else
                     a.state = ACTION_STATE_DISABLE;
@@ -1142,7 +1140,7 @@ class EditWidgetBase : ScrollWidgetBase, EditableContentListener, MenuItemAction
                     if (readOnly)
                         return true;
                     if (_selectionRange.empty) {
-                        if (_useSpacesForTabs) {
+                        if (useSpacesForTabs) {
                             // insert one or more spaces to 
                             EditOperation op = new EditOperation(EditAction.Replace, TextRange(_caretPos, _caretPos), [spacesForTab(_caretPos.pos)]);
                             _content.performOperation(op, this);
@@ -1157,7 +1155,7 @@ class EditWidgetBase : ScrollWidgetBase, EditableContentListener, MenuItemAction
                             return handleAction(new Action(EditorActions.Indent));
                         } else {
                             // insert tab
-                            if (_useSpacesForTabs) {
+                            if (useSpacesForTabs) {
                                 // insert one or more spaces to 
                                 EditOperation op = new EditOperation(EditAction.Replace, _selectionRange, [spacesForTab(_selectionRange.start.pos)]);
                                 _content.performOperation(op, this);
@@ -1286,7 +1284,7 @@ class EditWidgetBase : ScrollWidgetBase, EditableContentListener, MenuItemAction
             return src[unindentPos .. $].dup;
         } else {
             // indent
-            if (_useSpacesForTabs) {
+            if (useSpacesForTabs) {
                 if (cursor > 0)
                     cursorPos.pos += tabSize;
                 return spacesForTab(0) ~ src;
@@ -2039,12 +2037,12 @@ class EditBox : EditWidgetBase {
                 }
                 return true;
 			case EditorActions.ToggleBlockComment:
-                if (_content.syntaxHighlighter && _content.syntaxHighlighter.supportsToggleBlockComment && _content.syntaxHighlighter.canToggleBlockComment(_content, _selectionRange))
+                if (_content.syntaxHighlighter && _content.syntaxHighlighter.supportsToggleBlockComment && _content.syntaxHighlighter.canToggleBlockComment(_selectionRange))
-                    _content.syntaxHighlighter.toggleBlockComment(_content, _selectionRange, this);
+                    _content.syntaxHighlighter.toggleBlockComment(_selectionRange, this);
                 return true;
 			case EditorActions.ToggleLineComment:
-                if (_content.syntaxHighlighter && _content.syntaxHighlighter.supportsToggleLineComment && _content.syntaxHighlighter.canToggleLineComment(_content, _selectionRange))
+                if (_content.syntaxHighlighter && _content.syntaxHighlighter.supportsToggleLineComment && _content.syntaxHighlighter.canToggleLineComment(_selectionRange))
-                    _content.syntaxHighlighter.toggleLineComment(_content, _selectionRange, this);
+                    _content.syntaxHighlighter.toggleLineComment(_selectionRange, this);
                 return true;
 			case EditorActions.InsertLine:
                 {