[StickyScrolling] Move text and style calculation to StickyLine

Move the text and style calculation to the StickyLine itself in order to
enable the sticky line provider to overwrite the default behavior. This
is needed to apply custom texts or custom styles for the sticky lines.

Preparation for #2398

Author: Christopher-Hermann

bundles/org.eclipse.ui.editors/src/org/eclipse/ui/internal/texteditor/stickyscroll/DefaultStickyLinesProvider.java

@@ -33,9 +33,9 @@ public class DefaultStickyLinesProvider implements IStickyLinesProvider {
 	private StickyLinesProperties fProperties;
 
 	@Override
-	public List<StickyLine> getStickyLines(StyledText textWidget, int lineNumber, StickyLinesProperties properties) {
+	public List<IStickyLine> getStickyLines(StyledText textWidget, int lineNumber, StickyLinesProperties properties) {
 		this.fProperties= properties;
-		LinkedList<StickyLine> stickyLines= new LinkedList<>();
+		LinkedList<IStickyLine> stickyLines= new LinkedList<>();
 
 		try {
 			int startIndetation= getStartIndentation(lineNumber, textWidget);
@@ -50,7 +50,7 @@ public List<StickyLine> getStickyLines(StyledText textWidget, int lineNumber, St
 
 				if (indentation < previousIndetation) {
 					previousIndetation= indentation;
-					stickyLines.addFirst(new StickyLine(line, i));
+					stickyLines.addFirst(new StickyLine(i, textWidget));
 				}
 			}
 		} catch (IllegalArgumentException e) {

bundles/org.eclipse.ui.editors/src/org/eclipse/ui/internal/texteditor/stickyscroll/IStickyLine.java

@@ -0,0 +1,44 @@
+/*******************************************************************************
+ * Copyright (c) 2024 SAP SE.
+ *
+ * This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License 2.0
+ * which accompanies this distribution, and is available at
+ * https://www.eclipse.org/legal/epl-2.0/
+ *
+ * SPDX-License-Identifier: EPL-2.0
+ *
+ * Contributors:
+ *     SAP SE - initial API and implementation
+ *******************************************************************************/
+package org.eclipse.ui.internal.texteditor.stickyscroll;
+
+import org.eclipse.swt.custom.StyleRange;
+
+/**
+ * Representation of a sticky line.
+ */
+public interface IStickyLine {
+
+	/**
+	 * Returns the line number of the sticky line.
+	 * 
+	 * @return the line number of the sticky line
+	 */
+	int getLineNumber();
+
+	/**
+	 * Returns the text of the sticky line.
+	 * 
+	 * @return the text of the sticky line
+	 */
+	String getText();
+
+	/**
+	 * Returns the style ranges of the sticky line.
+	 * 
+	 * @return the style ranges of the sticky line
+	 */
+	StyleRange[] getStyleRanges();
+
+}

bundles/org.eclipse.ui.editors/src/org/eclipse/ui/internal/texteditor/stickyscroll/IStickyLinesProvider.java

@@ -37,7 +37,7 @@ public interface IStickyLinesProvider {
 	 * @param properties Properties for additional information
 	 * @return The list of sticky lines to show
 	 */
-	public List<StickyLine> getStickyLines(StyledText textWidget, int lineNumber, StickyLinesProperties properties);
+	public List<IStickyLine> getStickyLines(StyledText textWidget, int lineNumber, StickyLinesProperties properties);
 
 	/**
 	 * Additional properties and access in order to calculate the sticky lines.

bundles/org.eclipse.ui.editors/src/org/eclipse/ui/internal/texteditor/stickyscroll/StickyLine.java

@@ -13,13 +13,47 @@
  *******************************************************************************/
 package org.eclipse.ui.internal.texteditor.stickyscroll;
 
+import org.eclipse.swt.custom.StyleRange;
+import org.eclipse.swt.custom.StyledText;
+
 /**
- * 
- * A record representing a sticky line containing the text to display, and line number. It serves as
- * an abstraction to represent sticky line for sticky scrolling.
- * 
- * @param text the text of the corresponding sticky line
- * @param lineNumber the specific line number of the sticky line
+ * Default implementation of {@link IStickyLine}. Information about the text and style ranges are
+ * calculated from the given text widget.
  */
-public record StickyLine(String text, int lineNumber) {
+public class StickyLine implements IStickyLine {
+
+	private int lineNumber;
+
+	private String text;
+
+	private StyledText textWidget;
+
+	public StickyLine(int lineNumber, StyledText textWidget) {
+		this.lineNumber= lineNumber;
+		this.textWidget= textWidget;
+	}
+
+	@Override
+	public int getLineNumber() {
+		return this.lineNumber;
+	}
+
+	@Override
+	public String getText() {
+		if (text == null) {
+			text= textWidget.getLine(lineNumber);
+		}
+		return text;
+	}
+
+	@Override
+	public StyleRange[] getStyleRanges() {
+		int offsetAtLine= textWidget.getOffsetAtLine(lineNumber);
+		StyleRange[] styleRanges= textWidget.getStyleRanges(offsetAtLine, getText().length());
+		for (StyleRange styleRange : styleRanges) {
+			styleRange.start= styleRange.start - offsetAtLine;
+		}
+		return styleRanges;
+	}
+
 }

bundles/org.eclipse.ui.editors/src/org/eclipse/ui/internal/texteditor/stickyscroll/StickyScrollingControl.java

@@ -14,8 +14,6 @@
 package org.eclipse.ui.internal.texteditor.stickyscroll;
 
 import java.util.ArrayList;
-import java.util.Arrays;
-import java.util.Collections;
 import java.util.Iterator;
 import java.util.List;
 import java.util.StringJoiner;
@@ -65,7 +63,7 @@
 /**
  * This class builds a control that is rendered on top of the given source viewer. The controls
  * shows the sticky lines that are set via {@link #setStickyLines(List)} on top of the source
- * viewer. The {@link StickyLine#lineNumber()} is linked to to corresponding line number in the
+ * viewer. The {@link StickyLine#getLineNumber()} is linked to to corresponding line number in the
  * given source viewer, with index starting at 0.
  * 
  * As part of its responsibilities, the class handles layout arrangement and styling of the sticky
@@ -87,7 +85,7 @@ public class StickyScrollingControl {
 
 	private static final String DISABLE_CSS= "org.eclipse.e4.ui.css.disabled"; //$NON-NLS-1$
 
-	private List<StickyLine> stickyLines;
+	private List<IStickyLine> stickyLines;
 
 	private ISourceViewer sourceViewer;
 
@@ -135,7 +133,7 @@ public StickyScrollingControl(ISourceViewer sourceViewer, IVerticalRuler vertica
 	 * 
 	 * @param stickyLines The sticky lines to show
 	 */
-	public void setStickyLines(List<StickyLine> stickyLines) {
+	public void setStickyLines(List<IStickyLine> stickyLines) {
 		if (!stickyLines.equals(this.stickyLines)) {
 			this.stickyLines= stickyLines;
 			updateStickyScrollingControls();
@@ -206,9 +204,9 @@ private void updateStickyScrollingControls() {
 		StringJoiner stickyLineTextJoiner= new StringJoiner(System.lineSeparator());
 		StringJoiner stickyLineNumberJoiner= new StringJoiner(System.lineSeparator());
 		for (int i= 0; i < getNumberStickyLines(); i++) {
-			StickyLine stickyLine= stickyLines.get(i);
-			stickyLineTextJoiner.add(stickyLine.text());
-			int lineNumber= getSourceViewerLineNumber(stickyLine.lineNumber());
+			IStickyLine stickyLine= stickyLines.get(i);
+			stickyLineTextJoiner.add(stickyLine.getText());
+			int lineNumber= getSourceViewerLineNumber(stickyLine.getLineNumber());
 			stickyLineNumberJoiner.add(fillLineNumberWithLeadingSpaces(lineNumber + 1));
 		}
 
@@ -244,14 +242,20 @@ private void styleStickyLines() {
 			return;
 		}
 
-		List<StyleRange> stickyLinesStyleRanges= new ArrayList<>();
-		int stickyLineTextOffset= 0;
-		for (int i= 0; i < getNumberStickyLines(); i++) {
-			StickyLine stickyLine= stickyLines.get(i);
-			stickyLinesStyleRanges.addAll(getStickyLineStyleRanges(stickyLine, stickyLineTextOffset));
-			stickyLineTextOffset+= stickyLine.text().length() + System.lineSeparator().length();
+		int stickyLineOffset= 0;
+		List<StyleRange> styleRanges= new ArrayList<>();
+		for (IStickyLine stickyLine : stickyLines) {
+			StyleRange[] ranges= stickyLine.getStyleRanges();
+			if (ranges != null) {
+				for (StyleRange styleRange : ranges) {
+					styleRange.start+= stickyLineOffset;
+					styleRanges.add(styleRange);
+				}
+			}
+
+			stickyLineOffset+= stickyLine.getText().length() + System.lineSeparator().length();
 		}
-		stickyLineText.setStyleRanges(stickyLinesStyleRanges.toArray(StyleRange[]::new));
+		stickyLineText.setStyleRanges(styleRanges.toArray(StyleRange[]::new));
 
 		stickyLineNumber.setFont(textWidget.getFont());
 		stickyLineNumber.setStyleRange(new StyleRange(0, stickyLineNumber.getText().length(), settings.lineNumberColor(), null));
@@ -263,22 +267,6 @@ private void styleStickyLines() {
 		stickyLineText.setLeftMargin(textWidget.getLeftMargin());
 	}
 
-	private List<StyleRange> getStickyLineStyleRanges(StickyLine stickyLine, int stickyLineTextOffset) {
-		int lineNumber= stickyLine.lineNumber();
-		try {
-			StyledText textWidget= sourceViewer.getTextWidget();
-			int offsetAtLine= textWidget.getOffsetAtLine(lineNumber);
-			StyleRange[] styleRanges= textWidget.getStyleRanges(offsetAtLine, stickyLine.text().length());
-			for (StyleRange styleRange : styleRanges) {
-				styleRange.start= styleRange.start - offsetAtLine + stickyLineTextOffset;
-			}
-			return Arrays.asList(styleRanges);
-		} catch (IllegalArgumentException e) {
-			//Styling could not be copied, skip!
-			return Collections.emptyList();
-		}
-	}
-
 	private void layoutStickyLines() {
 		if (getNumberStickyLines() == 0) {
 			stickyLinesCanvas.setVisible(false);
@@ -365,12 +353,12 @@ private void calculateAndSetStickyLinesCanvasBounds() {
 
 	private void navigateToClickedLine(MouseEvent event) {
 		int clickedStickyLineIndex= stickyLineText.getLineIndex(event.y);
-		StickyLine clickedStickyLine= stickyLines.get(clickedStickyLineIndex);
+		IStickyLine clickedStickyLine= stickyLines.get(clickedStickyLineIndex);
 
 		try {
-			int offset= sourceViewer.getDocument().getLineOffset(clickedStickyLine.lineNumber());
+			int offset= sourceViewer.getDocument().getLineOffset(clickedStickyLine.getLineNumber());
 			sourceViewer.setSelectedRange(offset, 0);
-			ensureSourceViewerLineVisible(clickedStickyLine.lineNumber());
+			ensureSourceViewerLineVisible(clickedStickyLine.getLineNumber());
 		} catch (BadLocationException e) {
 			//Do not navigate
 		}

bundles/org.eclipse.ui.editors/src/org/eclipse/ui/internal/texteditor/stickyscroll/StickyScrollingHandler.java

@@ -153,7 +153,7 @@ public void viewportChanged(int newVerticalOffset) {
 	}
 
 	private void calculateAndShowStickyLines() {
-		List<StickyLine> stickyLines= Collections.emptyList();
+		List<IStickyLine> stickyLines= Collections.emptyList();
 
 		StyledText textWidget= sourceViewer.getTextWidget();
 		int startLine= textWidget.getTopIndex();
@@ -171,19 +171,19 @@ private void calculateAndShowStickyLines() {
 		stickyScrollingControl.setStickyLines(stickyLines);
 	}
 
-	private List<StickyLine> adaptStickyLinesToVisibleArea(List<StickyLine> stickyLines, int startLine) {
+	private List<IStickyLine> adaptStickyLinesToVisibleArea(List<IStickyLine> stickyLines, int startLine) {
 		if (stickyLines.isEmpty()) {
 			return stickyLines;
 		}
 
-		LinkedList<StickyLine> adaptedStickyLines= new LinkedList<>(stickyLines);
+		LinkedList<IStickyLine> adaptedStickyLines= new LinkedList<>(stickyLines);
 
 		int firstVisibleLine= startLine + adaptedStickyLines.size();
 		StyledText textWidget= sourceViewer.getTextWidget();
 		int maximumLines= textWidget.getLineCount();
 
 		for (int i= startLine + 1; i <= firstVisibleLine && i < maximumLines; i++) {
-			List<StickyLine> stickyLinesInLineI= stickyLinesProvider.getStickyLines(textWidget, i, stickyLinesProperties);
+			List<IStickyLine> stickyLinesInLineI= stickyLinesProvider.getStickyLines(textWidget, i, stickyLinesProperties);
 
 			if (stickyLinesInLineI.size() > adaptedStickyLines.size()) {
 				adaptedStickyLines= new LinkedList<>(stickyLinesInLineI);

tests/org.eclipse.ui.editors.tests/src/org/eclipse/ui/internal/texteditor/stickyscroll/DefaultStickyLinesProviderTest.java

@@ -16,7 +16,7 @@
 import static org.hamcrest.MatcherAssert.assertThat;
 import static org.hamcrest.Matchers.empty;
 import static org.hamcrest.Matchers.is;
-import static org.hamcrest.collection.IsIterableContainingInOrder.contains;
+import static org.junit.Assert.assertEquals;
 
 import java.util.List;
 
@@ -51,7 +51,7 @@ public void setup() {
 
 	@Test
 	public void testEmptySourceCode() {
-		List<StickyLine> stickyLines = stickyLinesProvider.getStickyLines(textWidget, 0, stickyLinesProperties);
+		List<IStickyLine> stickyLines = stickyLinesProvider.getStickyLines(textWidget, 0, stickyLinesProperties);
 
 		assertThat(stickyLines, is(empty()));
 	}
@@ -63,9 +63,10 @@ public void testSingleStickyLine() {
 				 line 2<""";
 		setText(text);
 
-		List<StickyLine> stickyLines = stickyLinesProvider.getStickyLines(textWidget, 1, stickyLinesProperties);
+		List<IStickyLine> stickyLines = stickyLinesProvider.getStickyLines(textWidget, 1, stickyLinesProperties);
 
-		assertThat(stickyLines, contains(new StickyLine("line 1", 0)));
+		assertEquals(1, stickyLines.size());
+		assertEquals(0, stickyLines.get(0).getLineNumber());
 	}
 
 	@Test
@@ -77,9 +78,10 @@ public void testLineUnderStickyLine() {
 				  line 4""";
 		setText(text);
 
-		List<StickyLine> stickyLines = stickyLinesProvider.getStickyLines(textWidget, 1, stickyLinesProperties);
+		List<IStickyLine> stickyLines = stickyLinesProvider.getStickyLines(textWidget, 1, stickyLinesProperties);
 
-		assertThat(stickyLines, contains(new StickyLine("line 1", 0)));
+		assertEquals(1, stickyLines.size());
+		assertEquals(0, stickyLines.get(0).getLineNumber());
 	}
 
 	@Test
@@ -91,9 +93,10 @@ public void testNewStickyRoot() {
 				 line 4<""";
 		setText(text);
 
-		List<StickyLine> stickyLines = stickyLinesProvider.getStickyLines(textWidget, 3, stickyLinesProperties);
+		List<IStickyLine> stickyLines = stickyLinesProvider.getStickyLines(textWidget, 3, stickyLinesProperties);
 
-		assertThat(stickyLines, contains(new StickyLine("line 3", 2)));
+		assertEquals(1, stickyLines.size());
+		assertEquals(2, stickyLines.get(0).getLineNumber());
 	}
 
 	@Test
@@ -106,9 +109,11 @@ public void testIgnoreEmptyLines() {
 				  line 3<""";
 		setText(text);
 
-		List<StickyLine> stickyLines = stickyLinesProvider.getStickyLines(textWidget, 4, stickyLinesProperties);
+		List<IStickyLine> stickyLines = stickyLinesProvider.getStickyLines(textWidget, 4, stickyLinesProperties);
 
-		assertThat(stickyLines, contains(new StickyLine("line 1", 0), new StickyLine(" line 2", 2)));
+		assertEquals(2, stickyLines.size());
+		assertEquals(0, stickyLines.get(0).getLineNumber());
+		assertEquals(2, stickyLines.get(1).getLineNumber());
 	}
 
 	@Test
@@ -120,9 +125,11 @@ public void testLinesWithTabs() {
 				\t\tline 3<""";
 		setText(text);
 
-		List<StickyLine> stickyLines = stickyLinesProvider.getStickyLines(textWidget, 2, stickyLinesProperties);
+		List<IStickyLine> stickyLines = stickyLinesProvider.getStickyLines(textWidget, 2, stickyLinesProperties);
 
-		assertThat(stickyLines, contains(new StickyLine("line 1", 0), new StickyLine("\tline 2", 1)));
+		assertEquals(2, stickyLines.size());
+		assertEquals(0, stickyLines.get(0).getLineNumber());
+		assertEquals(1, stickyLines.get(1).getLineNumber());
 	}
 
 	@Test
@@ -136,9 +143,11 @@ public void testStartAtEmptyLineWithNext() {
 		textWidget.setText(text);
 		textWidget.setTopIndex(3);
 
-		List<StickyLine> stickyLines = stickyLinesProvider.getStickyLines(textWidget, 3, stickyLinesProperties);
+		List<IStickyLine> stickyLines = stickyLinesProvider.getStickyLines(textWidget, 3, stickyLinesProperties);
 
-		assertThat(stickyLines, contains(new StickyLine("line 1", 0), new StickyLine(" line 2", 2)));
+		assertEquals(2, stickyLines.size());
+		assertEquals(0, stickyLines.get(0).getLineNumber());
+		assertEquals(2, stickyLines.get(1).getLineNumber());
 	}
 
 	@Test
@@ -151,9 +160,11 @@ public void testStartAtEmptyLineWithPrevious() {
 				line 4""";
 		setText(text);
 
-		List<StickyLine> stickyLines = stickyLinesProvider.getStickyLines(textWidget, 3, stickyLinesProperties);
+		List<IStickyLine> stickyLines = stickyLinesProvider.getStickyLines(textWidget, 3, stickyLinesProperties);
 
-		assertThat(stickyLines, contains(new StickyLine("line 1", 0), new StickyLine(" line 2", 1)));
+		assertEquals(2, stickyLines.size());
+		assertEquals(0, stickyLines.get(0).getLineNumber());
+		assertEquals(1, stickyLines.get(1).getLineNumber());
 	}
 
 	/**