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   1 /*
   2  * (c) Copyright IBM Corp. 2000, 2001.
   3  * All Rights Reserved.
   4  */
   5 package net.sourceforge.phpdt.internal.ui.text.link;
   6
   7 import java.util.Arrays;
   8 import java.util.Comparator;
   9 import java.util.HashMap;
  10 import java.util.Map;
  11
  12 import net.sourceforge.phpeclipse.PHPeclipsePlugin;
  13
  14 import org.eclipse.jface.text.BadLocationException;
  15 import org.eclipse.jface.text.BadPositionCategoryException;
  16 import org.eclipse.jface.text.DocumentEvent;
  17 import org.eclipse.jface.text.IDocument;
  18 import org.eclipse.jface.text.IDocumentExtension;
  19 import org.eclipse.jface.text.IDocumentListener;
  20 import org.eclipse.jface.text.IPositionUpdater;
  21 import org.eclipse.jface.text.Position;
  22 import org.eclipse.jface.text.TypedPosition;
  23 import org.eclipse.jface.util.Assert;
  24
  25 //import org.eclipse.jdt.internal.ui.JavaPlugin;
  26
  27 /**
  28  * This class manages linked positions in a document. Positions are linked
  29  * by type names. If positions have the same type name, they are considered
  30  * as <em>linked</em>.
  31  *
  32  * The manager remains active on a document until any of the following actions
  33  * occurs:
  34  *
  35  * <ul>
  36  *   <li>A document change is performed which would invalidate any of the
  37  *       above constraints.</li>
  38  *
  39  *   <li>The method <code>uninstall()</code> is called.</li>
  40  *
  41  *   <li>Another instance of <code>LinkedPositionManager</code> tries to
  42  *       gain control of the same document.
  43  * </ul>
  44  */
  45 public class LinkedPositionManager implements IDocumentListener, IPositionUpdater {
  46
  47         private static class PositionComparator implements Comparator {
  48                 /*
  49                  * @see Comparator#compare(Object, Object)
  50                  */
  51                 public int compare(Object object0, Object object1) {
  52                         Position position0= (Position) object0;
  53                         Position position1= (Position) object1;
  54
  55                         return position0.getOffset() - position1.getOffset();
  56                 }
  57         }
  58
  59         private class Replace implements IDocumentExtension.IReplace {
  60
  61                 private Position fReplacePosition;
  62                 private int fReplaceDeltaOffset;
  63                 private int fReplaceLength;
  64                 private String fReplaceText;
  65
  66                 public Replace(Position position, int deltaOffset, int length, String text) {
  67                         fReplacePosition= position;
  68                         fReplaceDeltaOffset= deltaOffset;
  69                         fReplaceLength= length;
  70                         fReplaceText= text;
  71                 }
  72
  73                 public void perform(IDocument document, IDocumentListener owner) {
  74                         document.removeDocumentListener(owner);
  75                         try {
  76                                 document.replace(fReplacePosition.getOffset() + fReplaceDeltaOffset, fReplaceLength, fReplaceText);
  77                         } catch (BadLocationException e) {
  78                                 PHPeclipsePlugin.log(e);
  79                                 // TBD
  80                         }
  81                         document.addDocumentListener(owner);
  82                 }
  83         }
  84
  85         private static final String LINKED_POSITION= "LinkedPositionManager.linked.position"; //$NON-NLS-1$
  86         private static final Comparator fgPositionComparator= new PositionComparator();
  87         private static final Map fgActiveManagers= new HashMap();
  88
  89         private IDocument fDocument;
  90
  91         private LinkedPositionListener fListener;
  92
  93         /**
  94          * Creates a <code>LinkedPositionManager</code> for a <code>IDocument</code>.
  95          *
  96          * @param document the document to use with linked positions.
  97          */
  98         public LinkedPositionManager(IDocument document) {
  99                 Assert.isNotNull(document);
 100
 101                 fDocument= document;
 102                 install();
 103         }
 104
 105         /**
 106          * Sets a listener to notify changes of current linked position.
 107          */
 108         public void setLinkedPositionListener(LinkedPositionListener listener) {
 109                 fListener= listener;
 110         }
 111
 112         /**
 113          * Adds a linked position to the manager.
 114          * There are the following constraints for linked positions:
 115          *
 116          * <ul>
 117          *   <li>Any two positions have spacing of at least one character.
 118          *       This implies that two positions must not overlap.</li>
 119          *
 120          *   <li>The string at any position must not contain line delimiters.</li>
 121          * </ul>
 122          *
 123          * @param offset the offset of the position.
 124          * @param length the length of the position.
 125          */
 126         public void addPosition(int offset, int length) throws BadLocationException {
 127                 Position[] positions= getPositions(fDocument);
 128
 129                 if (positions != null) {
 130                         for (int i = 0; i < positions.length; i++)
 131                                 if (collides(positions[i], offset, length))
 132                                         throw new BadLocationException(LinkedPositionMessages.getString(("LinkedPositionManager.error.position.collision"))); //$NON-NLS-1$
 133                 }
 134
 135                 String type= fDocument.get(offset, length);
 136
 137                 if (containsLineDelimiters(type))
 138                         throw new BadLocationException(LinkedPositionMessages.getString(("LinkedPositionManager.error.contains.line.delimiters"))); //$NON-NLS-1$
 139
 140                 try {
 141                         fDocument.addPosition(LINKED_POSITION, new TypedPosition(offset, length, type));
 142                 } catch (BadPositionCategoryException e) {
 143                         PHPeclipsePlugin.log(e);
 144                         Assert.isTrue(false);
 145                 }
 146         }
 147
 148         /**
 149          * Tests if a manager is already active for a document.
 150          */
 151         public static boolean hasActiveManager(IDocument document) {
 152                 return fgActiveManagers.get(document) != null;
 153         }
 154
 155         private void install() {
 156                 LinkedPositionManager manager= (LinkedPositionManager) fgActiveManagers.get(fDocument);
 157                 if (manager != null)
 158                         manager.leave(true);
 159
 160                 fgActiveManagers.put(fDocument, this);
 161
 162                 fDocument.addPositionCategory(LINKED_POSITION);
 163                 fDocument.addPositionUpdater(this);
 164                 fDocument.addDocumentListener(this);
 165         }
 166
 167         /**
 168          * Leaves the linked mode. If unsuccessful, the linked positions
 169          * are restored to the values at the time they were added.
 170          */
 171         public void uninstall(boolean success) {
 172                 fDocument.removeDocumentListener(this);
 173
 174                 try {
 175                         Position[] positions= getPositions(fDocument);
 176                         if ((!success) && (positions != null)) {
 177                                 // restore
 178                                 for (int i= 0; i != positions.length; i++) {
 179                                         TypedPosition position= (TypedPosition) positions[i];
 180                                         fDocument.replace(position.getOffset(), position.getLength(), position.getType());
 181                                 }
 182                         }
 183
 184                         fDocument.removePositionCategory(LINKED_POSITION);
 185
 186                 } catch (BadLocationException e) {
 187                         PHPeclipsePlugin.log(e);
 188                         Assert.isTrue(false);
 189
 190                 } catch (BadPositionCategoryException e) {
 191                         PHPeclipsePlugin.log(e);
 192                         Assert.isTrue(false);
 193
 194                 } finally {
 195                         fDocument.removePositionUpdater(this);
 196                         fgActiveManagers.remove(fDocument);
 197                 }
 198         }
 199
 200         /**
 201          * Returns the first linked position.
 202          *
 203          * @return returns <code>null</code> if no linked position exist.
 204          */
 205         public Position getFirstPosition() {
 206                 return getNextPosition(-1);
 207         }
 208
 209         /**
 210          * Returns the next linked position with an offset greater than <code>offset</code>.
 211          * If another position with the same type and offset lower than <code>offset</code>
 212          * exists, the position is skipped.
 213          *
 214          * @return returns <code>null</code> if no linked position exist.
 215          */
 216         public Position getNextPosition(int offset) {
 217                 Position[] positions= getPositions(fDocument);
 218                 return findNextPosition(positions, offset);
 219         }
 220
 221         private static Position findNextPosition(Position[] positions, int offset) {
 222                 // skip already visited types
 223                 for (int i= 0; i != positions.length; i++) {
 224                         if (positions[i].getOffset() > offset) {
 225                                 String type= ((TypedPosition) positions[i]).getType();
 226                                 int j;
 227                                 for (j = 0; j != i; j++)
 228                                         if (((TypedPosition) positions[j]).getType().equals(type))
 229                                                 break;
 230
 231                                 if (j == i)
 232                                         return positions[i];
 233                         }
 234                 }
 235
 236                 return null;
 237         }
 238
 239         /**
 240          * Returns the position with the greatest offset smaller than <code>offset</code>.
 241          *
 242          * @return returns <code>null</code> if no linked position exist.
 243          */
 244         public Position getPreviousPosition(int offset) {
 245                 Position[] positions= getPositions(fDocument);
 246                 if (positions == null)
 247                         return null;
 248
 249                 Position lastPosition= null;
 250                 Position position= getFirstPosition();
 251
 252                 while ((position != null) && (position.getOffset() < offset)) {
 253                         lastPosition= position;
 254                         position= findNextPosition(positions, position.getOffset());
 255                 }
 256
 257                 return lastPosition;
 258         }
 259
 260         private static Position[] getPositions(IDocument document) {
 261                 try {
 262                         Position[] positions= document.getPositions(LINKED_POSITION);
 263                         Arrays.sort(positions, fgPositionComparator);
 264                         return positions;
 265
 266                 } catch (BadPositionCategoryException e) {
 267                         PHPeclipsePlugin.log(e);
 268                         Assert.isTrue(false);
 269                 }
 270
 271                 return null;
 272         }
 273
 274         public static boolean includes(Position position, int offset, int length) {
 275                 return
 276                         (offset >= position.getOffset()) &&
 277                         (offset + length <= position.getOffset() + position.getLength());
 278         }
 279
 280         public static boolean excludes(Position position, int offset, int length) {
 281                 return
 282                         (offset + length <= position.getOffset()) ||
 283                         (position.getOffset() + position.getLength() <= offset);
 284         }
 285
 286         /*
 287          * Collides if spacing if positions intersect each other or are adjacent.
 288          */
 289         private static boolean collides(Position position, int offset, int length) {
 290                 return
 291                         (offset <= position.getOffset() + position.getLength()) &&
 292                         (position.getOffset() <= offset + length);
 293         }
 294
 295         private void leave(boolean success) {
 296                 uninstall(success);
 297
 298                 if (fListener != null)
 299                         fListener.exit(success);
 300         }
 301
 302         /*
 303          * @see IDocumentListener#documentAboutToBeChanged(DocumentEvent)
 304          */
 305         public void documentAboutToBeChanged(DocumentEvent event) {
 306                 IDocument document= event.getDocument();
 307
 308                 Position[] positions= getPositions(document);
 309                 Position position= findCurrentEditablePosition(positions, event.getOffset());
 310
 311                 // modification outside editable position
 312                 if (position == null) {
 313                         position= findCurrentPosition(positions, event.getOffset());
 314
 315                         // modification outside any position
 316                         if (position == null) {
 317                                 // check for destruction of constraints (spacing of at least 1)
 318                                 if ((event.getText().length() == 0) &&
 319                                         (findCurrentPosition(positions, event.getOffset()) != null) &&
 320                                         (findCurrentPosition(positions, event.getOffset() + event.getLength()) != null))
 321                                 {
 322                                         leave(true);
 323                                 }
 324
 325                         // modification intersects non-editable position
 326                         } else {
 327                                 leave(true);
 328                         }
 329
 330                 // modification intersects editable position
 331                 } else {
 332                         // modificaction inside editable position
 333                         if (includes(position, event.getOffset(), event.getLength())) {
 334                                 if (containsLineDelimiters(event.getText()))
 335                                         leave(true);
 336
 337                         // modificaction exceeds editable position
 338                         } else {
 339                                 leave(true);
 340                         }
 341                 }
 342         }
 343
 344         /*
 345          * @see IDocumentListener#documentChanged(DocumentEvent)
 346          */
 347         public void documentChanged(DocumentEvent event) {
 348                 IDocument document= event.getDocument();
 349
 350                 Position[] positions= getPositions(document);
 351                 TypedPosition currentPosition= (TypedPosition) findCurrentEditablePosition(positions, event.getOffset());
 352
 353                 // ignore document changes (assume it won't invalidate constraints)
 354                 if (currentPosition == null)
 355                         return;
 356
 357                 int deltaOffset= event.getOffset() - currentPosition.getOffset();
 358
 359                 if (fListener != null)
 360                         fListener.setCurrentPosition(currentPosition, deltaOffset + event.getText().length());
 361
 362                 for (int i= 0; i != positions.length; i++) {
 363                         TypedPosition p= (TypedPosition) positions[i];
 364
 365                         if (p.getType().equals(currentPosition.getType()) && !p.equals(currentPosition)) {
 366                                 Replace replace= new Replace(p, deltaOffset, event.getLength(), event.getText());
 367                                 ((IDocumentExtension) document).registerPostNotificationReplace(this, replace);
 368                         }
 369                 }
 370         }
 371
 372         /*
 373          * @see IPositionUpdater#update(DocumentEvent)
 374          */
 375         public void update(DocumentEvent event) {
 376                 int deltaLength= event.getText().length() - event.getLength();
 377
 378                 Position[] positions= getPositions(event.getDocument());
 379                 TypedPosition currentPosition= (TypedPosition) findCurrentPosition(positions, event.getOffset());
 380
 381                 // document change outside positions
 382                 if (currentPosition == null) {
 383
 384                         for (int i= 0; i != positions.length; i++) {
 385                                 TypedPosition position= (TypedPosition) positions[i];
 386                                 int offset= position.getOffset();
 387
 388                                 if (offset >= event.getOffset())
 389                                         position.setOffset(offset + deltaLength);
 390                         }
 391
 392                 // document change within a position
 393                 } else {
 394                         int length= currentPosition.getLength();
 395
 396                         for (int i= 0; i != positions.length; i++) {
 397                                 TypedPosition position= (TypedPosition) positions[i];
 398                                 int offset= position.getOffset();
 399
 400                                 if (position.equals(currentPosition)) {
 401                                         position.setLength(length + deltaLength);
 402                                 } else if (offset > currentPosition.getOffset()) {
 403                                         position.setOffset(offset + deltaLength);
 404                                 }
 405                         }
 406                 }
 407         }
 408
 409         private static Position findCurrentPosition(Position[] positions, int offset) {
 410                 for (int i= 0; i != positions.length; i++)
 411                         if (includes(positions[i], offset, 0))
 412                                 return positions[i];
 413
 414                 return null;
 415         }
 416
 417         private static Position findCurrentEditablePosition(Position[] positions, int offset) {
 418                 Position position= positions[0];
 419
 420                 while ((position != null) && !includes(position, offset, 0))
 421                         position= findNextPosition(positions, position.getOffset());
 422
 423                 return position;
 424         }
 425
 426         private boolean containsLineDelimiters(String string) {
 427                 String[] delimiters= fDocument.getLegalLineDelimiters();
 428
 429                 for (int i= 0; i != delimiters.length; i++)
 430                         if (string.indexOf(delimiters[i]) != -1)
 431                                 return true;
 432
 433                 return false;
 434         }
 435
 436         /**
 437          * Test if ok to modify through UI.
 438          */
 439         public boolean anyPositionIncludes(int offset, int length) {
 440                 Position[] positions= getPositions(fDocument);
 441
 442                 Position position= findCurrentEditablePosition(positions, offset);
 443                 if (position == null)
 444                         return false;
 445
 446                 return includes(position, offset, length);
 447         }
 448
 449 }