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