net.sourceforge.phpeclipse.ui/src/net/sourceforge/phpdt/internal/ui/text/SmartBackspaceManager.java

   1 /*******************************************************************************
   2  * Copyright (c) 2000, 2003 IBM Corporation and others.
   3  * All rights reserved. This program and the accompanying materials
   4  * are made available under the terms of the Common Public License v1.0
   5  * which accompanies this distribution, and is available at
   6  * http://www.eclipse.org/legal/cpl-v10.html
   7  *
   8  * Contributors:
   9  *     IBM Corporation - initial API and implementation
  10  *******************************************************************************/
  11 package net.sourceforge.phpdt.internal.ui.text;
  12
  13 import java.util.HashMap;
  14 import java.util.Iterator;
  15 import java.util.Map;
  16
  17 import net.sourceforge.phpdt.internal.ui.text.TypingRun.ChangeType;
  18
  19 //incastrix
  20 //import org.eclipse.jface.text.Assert;
  21 import org.eclipse.core.runtime.Assert;
  22 import org.eclipse.jface.text.BadLocationException;
  23 import org.eclipse.jface.text.IDocument;
  24 import org.eclipse.jface.text.IRegion;
  25 import org.eclipse.jface.text.ITextViewer;
  26 import org.eclipse.jface.text.ITextViewerExtension;
  27 import org.eclipse.jface.text.TextViewer;
  28 import org.eclipse.swt.SWT;
  29 import org.eclipse.swt.custom.VerifyKeyListener;
  30 import org.eclipse.swt.events.VerifyEvent;
  31 import org.eclipse.swt.graphics.Point;
  32 import org.eclipse.text.edits.MalformedTreeException;
  33 import org.eclipse.text.edits.TextEdit;
  34
  35 /**
  36  * Installs as a verify key listener on a viewer and overwrites the behaviour of
  37  * the backspace key. Clients may register undo specifications for certain
  38  * offsets in a document. The <code>SmartBackspaceManager</code> will manage
  39  * the specfications and execute the contained <code>TextEdit</code>s when
  40  * backspace is pressed at the given offset and the specification is still
  41  * valid.
  42  * <p>
  43  * Undo specifications are removed after a number of typing runs.
  44  * </p>
  45  *
  46  * @since 3.0
  47  */
  48 public class SmartBackspaceManager {
  49         /* independent of JDT - may be moved to jface.text */
  50
  51         /**
  52          * An undo specification describes the change that should be executed if
  53          * backspace is pressed at its trigger offset.
  54          *
  55          * @since 3.0
  56          */
  57         public static final class UndoSpec {
  58                 private final int triggerOffset;
  59
  60                 private final IRegion selection;
  61
  62                 private final TextEdit[] undoEdits;
  63
  64                 private final UndoSpec child;
  65
  66                 int lives;
  67
  68                 /**
  69                  * Creates a new spec. A specification consists of a number of
  70                  * <code>TextEdit</code> s that will be executed when backspace is
  71                  * pressed at <code>triggerOffset</code>. The spec will be removed
  72                  * when it is executed, or if more than <code>lives</code>
  73                  * <code>TypingRun</code>s
  74                  * have ended after registering the spec.
  75                  * <p>
  76                  * Optionally, a child specification can be registered. After executing
  77                  * the spec, the child spec will be registered with the manager. This
  78                  * allows to create chains of <code>UndoSpec</code>s that will be
  79                  * executed upon repeated pressing of backspace.
  80                  * </p>
  81                  *
  82                  * @param triggerOffset
  83                  *            the offset where this spec is active
  84                  * @param selection
  85                  *            the selection after executing the undo spec
  86                  * @param edits
  87                  *            the <code>TextEdit</code> s to perform when executing
  88                  *            the spec
  89                  * @param lives
  90                  *            the number of <code>TypingRun</code> s before removing
  91                  *            the spec
  92                  * @param child
  93                  *            a child specification that will be registered after
  94                  *            executing this spec, or <code>null</code>
  95                  */
  96                 public UndoSpec(int triggerOffset, IRegion selection, TextEdit[] edits,
  97                                 int lives, UndoSpec child) {
  98                         Assert.isLegal(triggerOffset >= 0);
  99                         Assert.isLegal(selection != null);
 100                         Assert.isLegal(lives >= 0);
 101                         Assert.isLegal(edits != null);
 102                         Assert.isLegal(edits.length > 0);
 103                         for (int i = 0; i < edits.length; i++) {
 104                                 Assert.isLegal(edits[i] != null);
 105                         }
 106
 107                         this.triggerOffset = triggerOffset;
 108                         this.selection = selection;
 109                         this.undoEdits = edits;
 110                         this.lives = lives;
 111                         this.child = child;
 112                 }
 113         }
 114
 115         private class BackspaceListener implements VerifyKeyListener {
 116
 117                 /*
 118                  * @see org.eclipse.swt.custom.VerifyKeyListener#verifyKey(org.eclipse.swt.events.VerifyEvent)
 119                  */
 120                 public void verifyKey(VerifyEvent event) {
 121                         if (fViewer != null && isBackspace(event)) {
 122                                 int offset = getCaretOffset();
 123                                 UndoSpec spec = removeEdit(offset);
 124                                 if (spec != null) {
 125                                         try {
 126                                                 beginChange();
 127                                                 for (int i = 0; i < spec.undoEdits.length; i++) {
 128                                                         spec.undoEdits[i].apply(getDocument(),
 129                                                                         TextEdit.UPDATE_REGIONS);
 130                                                 }
 131                                                 fViewer.setSelectedRange(spec.selection.getOffset(),
 132                                                                 spec.selection.getLength());
 133                                                 if (spec.child != null)
 134                                                         register(spec.child);
 135                                         } catch (MalformedTreeException e) {
 136                                                 // fall back to standard bs
 137                                                 return;
 138                                         } catch (BadLocationException e) {
 139                                                 // fall back to standard bs
 140                                                 return;
 141                                         } finally {
 142                                                 endChange();
 143                                         }
 144                                         event.doit = false;
 145                                 }
 146
 147                         }
 148                 }
 149
 150                 private void beginChange() {
 151                         ITextViewer viewer = fViewer;
 152                         if (viewer instanceof TextViewer) {
 153                                 TextViewer v = (TextViewer) viewer;
 154                                 v.getRewriteTarget().beginCompoundChange();
 155                                 v.setRedraw(false);
 156                         }
 157                 }
 158
 159                 private void endChange() {
 160                         ITextViewer viewer = fViewer;
 161                         if (viewer instanceof TextViewer) {
 162                                 TextViewer v = (TextViewer) viewer;
 163                                 v.getRewriteTarget().endCompoundChange();
 164                                 v.setRedraw(true);
 165                         }
 166                 }
 167
 168                 private boolean isBackspace(VerifyEvent event) {
 169                         return event.doit == true && event.character == SWT.BS
 170                                         && event.stateMask == 0;
 171                 }
 172
 173                 private int getCaretOffset() {
 174                         ITextViewer viewer = fViewer;
 175                         Point point = viewer.getSelectedRange();
 176                         return point.x;
 177                 }
 178
 179         }
 180
 181         private ITextViewer fViewer;
 182
 183         private BackspaceListener fBackspaceListener;
 184
 185         private Map fSpecs;
 186
 187         private TypingRunDetector fRunDetector;
 188
 189         private ITypingRunListener fRunListener;
 190
 191         /**
 192          * Registers an undo specification with this manager.
 193          *
 194          * @param spec
 195          *            the specification to register
 196          * @throws IllegalStateException
 197          *             if the manager is not installed
 198          */
 199         public void register(UndoSpec spec) {
 200                 if (fViewer == null)
 201                         throw new IllegalStateException();
 202
 203                 ensureListenerInstalled();
 204                 addEdit(spec);
 205         }
 206
 207         private void addEdit(UndoSpec spec) {
 208                 Integer i = new Integer(spec.triggerOffset);
 209                 fSpecs.put(i, spec);
 210         }
 211
 212         private UndoSpec removeEdit(int offset) {
 213                 Integer i = new Integer(offset);
 214                 UndoSpec spec = (UndoSpec) fSpecs.remove(i);
 215                 return spec;
 216         }
 217
 218         private void ensureListenerInstalled() {
 219                 if (fBackspaceListener == null) {
 220                         fBackspaceListener = new BackspaceListener();
 221                         ITextViewer viewer = fViewer;
 222                         if (viewer instanceof ITextViewerExtension)
 223                                 ((ITextViewerExtension) viewer)
 224                                                 .prependVerifyKeyListener(fBackspaceListener);
 225                         else
 226                                 viewer.getTextWidget().addVerifyKeyListener(fBackspaceListener);
 227                 }
 228         }
 229
 230         private void ensureListenerRemoved() {
 231                 if (fBackspaceListener != null) {
 232                         ITextViewer viewer = fViewer;
 233                         if (viewer instanceof ITextViewerExtension)
 234                                 ((ITextViewerExtension) viewer)
 235                                                 .removeVerifyKeyListener(fBackspaceListener);
 236                         else
 237                                 viewer.getTextWidget().removeVerifyKeyListener(
 238                                                 fBackspaceListener);
 239                         fBackspaceListener = null;
 240                 }
 241         }
 242
 243         private IDocument getDocument() {
 244                 return fViewer.getDocument();
 245         }
 246
 247         /**
 248          * Installs the receiver on a text viewer.
 249          *
 250          * @param viewer
 251          */
 252         public void install(ITextViewer viewer) {
 253                 Assert.isLegal(viewer != null);
 254
 255                 fViewer = viewer;
 256                 fSpecs = new HashMap();
 257                 fRunDetector = new TypingRunDetector();
 258                 fRunDetector.install(viewer);
 259                 fRunListener = new ITypingRunListener() {
 260
 261                         /*
 262                          * @see org.eclipse.jface.text.TypingRunDetector.ITypingRunListener#typingRunStarted(org.eclipse.jface.text.TypingRunDetector.TypingRun)
 263                          */
 264                         public void typingRunStarted(TypingRun run) {
 265                         }
 266
 267                         /*
 268                          * @see org.eclipse.jface.text.TypingRunDetector.ITypingRunListener#typingRunEnded(org.eclipse.jface.text.TypingRunDetector.TypingRun)
 269                          */
 270                         public void typingRunEnded(TypingRun run, ChangeType reason) {
 271                                 if (reason == TypingRun.SELECTION)
 272                                         fSpecs.clear();
 273                                 else
 274                                         prune();
 275                         }
 276                 };
 277                 fRunDetector.addTypingRunListener(fRunListener);
 278         }
 279
 280         private void prune() {
 281                 for (Iterator it = fSpecs.values().iterator(); it.hasNext();) {
 282                         UndoSpec spec = (UndoSpec) it.next();
 283                         if (--spec.lives < 0)
 284                                 it.remove();
 285                 }
 286         }
 287
 288         /**
 289          * Uninstalls the receiver. No undo specifications may be registered on an
 290          * uninstalled manager.
 291          */
 292         public void uninstall() {
 293                 if (fViewer != null) {
 294                         fRunDetector.removeTypingRunListener(fRunListener);
 295                         fRunDetector.uninstall();
 296                         fRunDetector = null;
 297                         ensureListenerRemoved();
 298                         fViewer = null;
 299                 }
 300         }
 301 }