| /******************************************************************************* |
| * Copyright (c) 2000, 2011 IBM Corporation and others. |
| * |
| * 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: |
| * IBM Corporation - initial API and implementation |
| *******************************************************************************/ |
| package org.eclipse.jdt.internal.ui.text; |
| |
| import java.util.HashMap; |
| import java.util.Iterator; |
| import java.util.Map; |
| |
| import org.eclipse.swt.SWT; |
| import org.eclipse.swt.custom.VerifyKeyListener; |
| import org.eclipse.swt.events.VerifyEvent; |
| import org.eclipse.swt.graphics.Point; |
| |
| import org.eclipse.core.runtime.Assert; |
| |
| import org.eclipse.text.edits.MalformedTreeException; |
| import org.eclipse.text.edits.TextEdit; |
| |
| import org.eclipse.jface.text.BadLocationException; |
| import org.eclipse.jface.text.IDocument; |
| import org.eclipse.jface.text.IRegion; |
| import org.eclipse.jface.text.ITextViewer; |
| import org.eclipse.jface.text.ITextViewerExtension; |
| import org.eclipse.jface.text.TextViewer; |
| |
| import org.eclipse.jdt.internal.ui.text.TypingRun.ChangeType; |
| |
| |
| /** |
| * Installs as a verify key listener on a viewer and overwrites the behavior |
| * of the backspace key. Clients may register undo specifications for certain |
| * offsets in a document. The <code>SmartBackspaceManager</code> will manage the |
| * specifications and execute the contained <code>TextEdit</code>s when backspace |
| * is pressed at the given offset and the specification is still valid. |
| * <p> |
| * Undo specifications are removed after a number of typing runs. |
| * </p> |
| * |
| * @since 3.0 |
| */ |
| public class SmartBackspaceManager { |
| /* independent of JDT - may be moved to jface.text */ |
| |
| /** |
| * An undo specification describes the change that should be executed if |
| * backspace is pressed at its trigger offset. |
| * |
| * @since 3.0 |
| */ |
| public static final class UndoSpec { |
| private final int triggerOffset; |
| private final IRegion selection; |
| private final TextEdit[] undoEdits; |
| private final UndoSpec child; |
| int lives; |
| |
| /** |
| * Creates a new spec. A specification consists of a number of |
| * <code>TextEdit</code>s that will be executed when backspace is |
| * pressed at <code>triggerOffset</code>. The spec will be removed |
| * when it is executed, or if more than <code>lives</code> |
| * <code>TypingRun</code>s have ended after registering the spec. |
| * <p> |
| * Optionally, a child specification can be registered. After executing |
| * the spec, the child spec will be registered with the manager. This allows |
| * to create chains of <code>UndoSpec</code>s that will be executed upon |
| * repeated pressing of backspace. |
| * </p> |
| * |
| * @param triggerOffset the offset where this spec is active |
| * @param selection the selection after executing the undo spec |
| * @param edits the <code>TextEdit</code>s to perform when executing |
| * the spec |
| * @param lives the number of <code>TypingRun</code>s before removing |
| * the spec |
| * @param child a child specification that will be registered after |
| * executing this spec, or <code>null</code> |
| */ |
| public UndoSpec(int triggerOffset, IRegion selection, TextEdit[] edits, int lives, UndoSpec child) { |
| Assert.isLegal(triggerOffset >= 0); |
| Assert.isLegal(selection != null); |
| Assert.isLegal(lives >= 0); |
| Assert.isLegal(edits != null); |
| Assert.isLegal(edits.length > 0); |
| for (int i= 0; i < edits.length; i++) { |
| Assert.isLegal(edits[i] != null); |
| } |
| |
| this.triggerOffset= triggerOffset; |
| this.selection= selection; |
| this.undoEdits= edits; |
| this.lives= lives; |
| this.child= child; |
| } |
| } |
| |
| |
| private class BackspaceListener implements VerifyKeyListener { |
| |
| /* |
| * @see org.eclipse.swt.custom.VerifyKeyListener#verifyKey(org.eclipse.swt.events.VerifyEvent) |
| */ |
| @Override |
| public void verifyKey(VerifyEvent event) { |
| if (fViewer != null && isBackspace(event)) { |
| int offset= getCaretOffset(); |
| UndoSpec spec= removeEdit(offset); |
| if (spec != null) { |
| try { |
| beginChange(); |
| for (int i= 0; i < spec.undoEdits.length; i++) { |
| spec.undoEdits[i].apply(getDocument(), TextEdit.UPDATE_REGIONS); |
| } |
| fViewer.setSelectedRange(spec.selection.getOffset(), spec.selection.getLength()); |
| if (spec.child != null) |
| register(spec.child); |
| } catch (MalformedTreeException e) { |
| // fall back to standard bs |
| return; |
| } catch (BadLocationException e) { |
| // fall back to standard bs |
| return; |
| } finally { |
| endChange(); |
| } |
| event.doit= false; |
| } |
| |
| } |
| } |
| |
| private void beginChange() { |
| ITextViewer viewer= fViewer; |
| if (viewer instanceof TextViewer) { |
| TextViewer v= (TextViewer) viewer; |
| v.getRewriteTarget().beginCompoundChange(); |
| } |
| } |
| |
| private void endChange() { |
| ITextViewer viewer= fViewer; |
| if (viewer instanceof TextViewer) { |
| TextViewer v= (TextViewer) viewer; |
| v.getRewriteTarget().endCompoundChange(); |
| } |
| } |
| |
| private boolean isBackspace(VerifyEvent event) { |
| return event.doit == true && event.character == SWT.BS && event.stateMask == 0; |
| } |
| |
| private int getCaretOffset() { |
| ITextViewer viewer= fViewer; |
| Point point= viewer.getSelectedRange(); |
| return point.x; |
| } |
| |
| } |
| |
| private ITextViewer fViewer; |
| private BackspaceListener fBackspaceListener; |
| private Map<Integer, UndoSpec> fSpecs; |
| private TypingRunDetector fRunDetector; |
| private ITypingRunListener fRunListener; |
| |
| /** |
| * Registers an undo specification with this manager. |
| * |
| * @param spec the specification to register |
| * @throws IllegalStateException if the manager is not installed |
| */ |
| public void register(UndoSpec spec) { |
| if (fViewer == null) |
| throw new IllegalStateException(); |
| |
| ensureListenerInstalled(); |
| addEdit(spec); |
| } |
| |
| private void addEdit(UndoSpec spec) { |
| Integer i= Integer.valueOf(spec.triggerOffset); |
| fSpecs.put(i, spec); |
| } |
| |
| private UndoSpec removeEdit(int offset) { |
| Integer i= Integer.valueOf(offset); |
| UndoSpec spec= fSpecs.remove(i); |
| return spec; |
| } |
| |
| private void ensureListenerInstalled() { |
| if (fBackspaceListener == null) { |
| fBackspaceListener= new BackspaceListener(); |
| ITextViewer viewer= fViewer; |
| if (viewer instanceof ITextViewerExtension) |
| ((ITextViewerExtension) viewer).prependVerifyKeyListener(fBackspaceListener); |
| else |
| viewer.getTextWidget().addVerifyKeyListener(fBackspaceListener); |
| } |
| } |
| |
| private void ensureListenerRemoved() { |
| if (fBackspaceListener != null) { |
| ITextViewer viewer= fViewer; |
| if (viewer instanceof ITextViewerExtension) |
| ((ITextViewerExtension) viewer).removeVerifyKeyListener(fBackspaceListener); |
| else |
| viewer.getTextWidget().removeVerifyKeyListener(fBackspaceListener); |
| fBackspaceListener= null; |
| } |
| } |
| |
| private IDocument getDocument() { |
| return fViewer.getDocument(); |
| } |
| |
| /** |
| * Installs the receiver on a text viewer. |
| * |
| * @param viewer the text viewer |
| */ |
| public void install(ITextViewer viewer) { |
| Assert.isLegal(viewer != null); |
| |
| fViewer= viewer; |
| fSpecs= new HashMap<>(); |
| fRunDetector= new TypingRunDetector(); |
| fRunDetector.install(viewer); |
| fRunListener= new ITypingRunListener() { |
| |
| /* |
| * @see org.eclipse.jface.text.TypingRunDetector.ITypingRunListener#typingRunStarted(org.eclipse.jface.text.TypingRunDetector.TypingRun) |
| */ |
| @Override |
| public void typingRunStarted(TypingRun run) { |
| } |
| |
| /* |
| * @see org.eclipse.jface.text.TypingRunDetector.ITypingRunListener#typingRunEnded(org.eclipse.jface.text.TypingRunDetector.TypingRun) |
| */ |
| @Override |
| public void typingRunEnded(TypingRun run, ChangeType reason) { |
| if (reason == TypingRun.SELECTION) |
| fSpecs.clear(); |
| else |
| prune(); |
| } |
| }; |
| fRunDetector.addTypingRunListener(fRunListener); |
| } |
| |
| private void prune() { |
| for (Iterator<UndoSpec> it= fSpecs.values().iterator(); it.hasNext();) { |
| UndoSpec spec= it.next(); |
| if (--spec.lives < 0) |
| it.remove(); |
| } |
| } |
| |
| /** |
| * Uninstalls the receiver. No undo specifications may be registered on an |
| * uninstalled manager. |
| */ |
| public void uninstall() { |
| if (fViewer != null) { |
| fRunDetector.removeTypingRunListener(fRunListener); |
| fRunDetector.uninstall(); |
| fRunDetector= null; |
| ensureListenerRemoved(); |
| fViewer= null; |
| } |
| } |
| } |