ltk/org.eclipse.statet.ltk.ui/src/org/eclipse/statet/ltk/ui/sourceediting/actions/GotoMatchingBracketHandler.java

/*=============================================================================#
 # Copyright (c) 2006, 2020 Stephan Wahlbrink and others.
 # 
 # This program and the accompanying materials are made available under the
 # terms of the Eclipse Public License 2.0 which is available at
 # https://www.eclipse.org/legal/epl-2.0, or the Apache License, Version 2.0
 # which is available at https://www.apache.org/licenses/LICENSE-2.0.
 # 
 # SPDX-License-Identifier: EPL-2.0 OR Apache-2.0
 # 
 # Contributors:
 #     Stephan Wahlbrink <sw@wahlbrink.eu> - initial API and implementation
 #=============================================================================*/

package org.eclipse.statet.ltk.ui.sourceediting.actions;

import org.eclipse.core.commands.AbstractHandler;
import org.eclipse.core.commands.ExecutionEvent;
import org.eclipse.core.commands.ExecutionException;
import org.eclipse.jface.text.IDocument;
import org.eclipse.jface.text.IRegion;
import org.eclipse.jface.text.ITextSelection;
import org.eclipse.jface.text.ITextViewerExtension5;
import org.eclipse.jface.text.source.ICharacterPairMatcher;
import org.eclipse.jface.text.source.ISourceViewer;
import org.eclipse.swt.widgets.Display;
import org.eclipse.ui.texteditor.IEditorStatusLine;

import org.eclipse.statet.ecommons.text.ICharPairMatcher;

import org.eclipse.statet.internal.ltk.ui.EditingMessages;
import org.eclipse.statet.ltk.ui.sourceediting.ISourceEditor;


public class GotoMatchingBracketHandler extends AbstractHandler {
	
	
	private final ISourceEditor sourceEditor;
	
	private final ICharPairMatcher pairMatcher;
	
	
	public GotoMatchingBracketHandler(final ICharPairMatcher pairMatcher, final ISourceEditor editor) {
		assert (pairMatcher != null);
		assert (editor != null);
		this.sourceEditor= editor;
		this.pairMatcher= pairMatcher;
		
//		setBaseEnabled(true);
	}
	
	
	@Override
	public Object execute(final ExecutionEvent event) throws ExecutionException {
		gotoMatchingBracket();
		
		return null;
	}
	
	/**
	 * Jumps to the matching bracket.
	 */
	public void gotoMatchingBracket() {
		final ISourceViewer sourceViewer= this.sourceEditor.getViewer();
		if (sourceViewer == null) {
			return;
		}
		final IDocument document= sourceViewer.getDocument();
		
		final ITextSelection selection= (ITextSelection) sourceViewer.getSelectionProvider().getSelection();
		final int offset= selection.getOffset();
		final int selectionLength= selection.getLength();
		
		final IRegion region= (selectionLength <= 1) ?
				this.pairMatcher.match(document, offset, (selection.getLength() == 0)): null;
		{	String message= null;
			if (region == null) {
				message= EditingMessages.GotoMatchingBracketAction_error_InvalidSelection;
			}
			else if (region.getLength() < 2) {
				if (region.getLength() >= 0) {
					return; // invalid
				}
				message= EditingMessages.GotoMatchingBracketAction_error_NoMatchingBracket;
			}
			if (message != null) {
				final IEditorStatusLine statusLine= this.sourceEditor.getAdapter(IEditorStatusLine.class);
				if (statusLine != null) {
					statusLine.setMessage(true, message, null);
				}
				Display.getCurrent().beep();
				return;
			}
		}
		
		{	final int targetOffset= (this.pairMatcher.getAnchor() == ICharacterPairMatcher.RIGHT) ?
					region.getOffset() + 1 : region.getOffset() + region.getLength() - 1;
			
			boolean visible= false;
			if (sourceViewer instanceof ITextViewerExtension5) {
				final ITextViewerExtension5 extension= (ITextViewerExtension5) sourceViewer;
				visible= (extension.modelOffset2WidgetOffset(targetOffset) > -1);
			} else {
				final IRegion visibleRegion= sourceViewer.getVisibleRegion();
				visible= (targetOffset >= visibleRegion.getOffset() && targetOffset <= visibleRegion.getOffset() + visibleRegion.getLength());
			}
			
			if (!visible) {
				final IEditorStatusLine statusLine= this.sourceEditor.getAdapter(IEditorStatusLine.class);
				if (statusLine != null) {
					statusLine.setMessage(true, EditingMessages.GotoMatchingBracketAction_error_BracketOutsideSelectedElement, null);
				}
				Display.getCurrent().beep();
				return;
			}
			
			sourceViewer.setSelectedRange(targetOffset, 0);
			sourceViewer.revealRange(targetOffset, 0);
		}
	}
	
}