1) Moved net.sourceforge.phpeclipse.ui\src\net\sourceforge\phpdt back to net.sourcefo...
[phpeclipse.git] / net.sourceforge.phpeclipse / src / net / sourceforge / phpdt / internal / ui / text / SmartBackspaceManager.java
diff --git a/net.sourceforge.phpeclipse/src/net/sourceforge/phpdt/internal/ui/text/SmartBackspaceManager.java b/net.sourceforge.phpeclipse/src/net/sourceforge/phpdt/internal/ui/text/SmartBackspaceManager.java
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+/*******************************************************************************
+ * Copyright (c) 2000, 2003 IBM Corporation and others.
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the Common Public License v1.0
+ * which accompanies this distribution, and is available at
+ * http://www.eclipse.org/legal/cpl-v10.html
+ *
+ * Contributors:
+ *     IBM Corporation - initial API and implementation
+ *******************************************************************************/
+package net.sourceforge.phpdt.internal.ui.text;
+
+import java.util.HashMap;
+import java.util.Iterator;
+import java.util.Map;
+
+import net.sourceforge.phpdt.internal.ui.text.TypingRun.ChangeType;
+
+//incastrix
+//import org.eclipse.jface.text.Assert;
+import org.eclipse.core.runtime.Assert;
+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.swt.SWT;
+import org.eclipse.swt.custom.VerifyKeyListener;
+import org.eclipse.swt.events.VerifyEvent;
+import org.eclipse.swt.graphics.Point;
+import org.eclipse.text.edits.MalformedTreeException;
+import org.eclipse.text.edits.TextEdit;
+
+/**
+ * Installs as a verify key listener on a viewer and overwrites the behaviour of
+ * the backspace key. Clients may register undo specifications for certain
+ * offsets in a document. The <code>SmartBackspaceManager</code> will manage
+ * the specfications 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)
+                */
+               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();
+                               v.setRedraw(false);
+                       }
+               }
+
+               private void endChange() {
+                       ITextViewer viewer = fViewer;
+                       if (viewer instanceof TextViewer) {
+                               TextViewer v = (TextViewer) viewer;
+                               v.getRewriteTarget().endCompoundChange();
+                               v.setRedraw(true);
+                       }
+               }
+
+               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 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 = new Integer(spec.triggerOffset);
+               fSpecs.put(i, spec);
+       }
+
+       private UndoSpec removeEdit(int offset) {
+               Integer i = new Integer(offset);
+               UndoSpec spec = (UndoSpec) 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
+        */
+       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)
+                        */
+                       public void typingRunStarted(TypingRun run) {
+                       }
+
+                       /*
+                        * @see org.eclipse.jface.text.TypingRunDetector.ITypingRunListener#typingRunEnded(org.eclipse.jface.text.TypingRunDetector.TypingRun)
+                        */
+                       public void typingRunEnded(TypingRun run, ChangeType reason) {
+                               if (reason == TypingRun.SELECTION)
+                                       fSpecs.clear();
+                               else
+                                       prune();
+                       }
+               };
+               fRunDetector.addTypingRunListener(fRunListener);
+       }
+
+       private void prune() {
+               for (Iterator it = fSpecs.values().iterator(); it.hasNext();) {
+                       UndoSpec spec = (UndoSpec) 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;
+               }
+       }
+}