net.sourceforge.phpeclipse/src/net/sourceforge/phpdt/internal/compiler/flow/FlowContext.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.compiler.flow;
  12
  13 import net.sourceforge.phpdt.core.compiler.CharOperation;
  14 import net.sourceforge.phpdt.internal.compiler.ast.ASTNode;
  15 import net.sourceforge.phpdt.internal.compiler.ast.AbstractMethodDeclaration;
  16 import net.sourceforge.phpdt.internal.compiler.ast.Reference;
  17 import net.sourceforge.phpdt.internal.compiler.ast.TryStatement;
  18 import net.sourceforge.phpdt.internal.compiler.codegen.Label;
  19 import net.sourceforge.phpdt.internal.compiler.lookup.BlockScope;
  20 import net.sourceforge.phpdt.internal.compiler.lookup.ReferenceBinding;
  21 import net.sourceforge.phpdt.internal.compiler.lookup.Scope;
  22 import net.sourceforge.phpdt.internal.compiler.lookup.TypeBinding;
  23 import net.sourceforge.phpdt.internal.compiler.lookup.TypeConstants;
  24 import net.sourceforge.phpdt.internal.compiler.lookup.VariableBinding;
  25
  26 /**
  27  * Reflects the context of code analysis, keeping track of enclosing try
  28  * statements, exception handlers, etc...
  29  */
  30 public class FlowContext implements TypeConstants {
  31
  32         public ASTNode associatedNode;
  33
  34         public FlowContext parent;
  35
  36         public final static FlowContext NotContinuableContext = new FlowContext(
  37                         null, null);
  38
  39         public FlowContext(FlowContext parent, ASTNode associatedNode) {
  40
  41                 this.parent = parent;
  42                 this.associatedNode = associatedNode;
  43         }
  44
  45         public Label breakLabel() {
  46
  47                 return null;
  48         }
  49
  50         public void checkExceptionHandlers(TypeBinding[] raisedExceptions,
  51                         ASTNode location, FlowInfo flowInfo, BlockScope scope) {
  52
  53                 // check that all the argument exception types are handled
  54                 // JDK Compatible implementation - when an exception type is thrown,
  55                 // all related catch blocks are marked as reachable... instead of those
  56                 // only
  57                 // until the point where it is safely handled (Smarter - see comment at
  58                 // the end)
  59                 int remainingCount; // counting the number of remaining unhandled
  60                                                         // exceptions
  61                 int raisedCount; // total number of exceptions raised
  62                 if ((raisedExceptions == null)
  63                                 || ((raisedCount = raisedExceptions.length) == 0))
  64                         return;
  65                 remainingCount = raisedCount;
  66
  67                 // duplicate the array of raised exceptions since it will be updated
  68                 // (null replaces any handled exception)
  69                 System.arraycopy(raisedExceptions, 0,
  70                                 (raisedExceptions = new TypeBinding[raisedCount]), 0,
  71                                 raisedCount);
  72                 FlowContext traversedContext = this;
  73
  74                 while (traversedContext != null) {
  75                         ASTNode sub;
  76                         if (((sub = traversedContext.subRoutine()) != null)
  77                                         && sub.cannotReturn()) {
  78                                 // traversing a non-returning subroutine means that all
  79                                 // unhandled
  80                                 // exceptions will actually never get sent...
  81                                 return;
  82                         }
  83                         // filter exceptions that are locally caught from the innermost
  84                         // enclosing
  85                         // try statement to the outermost ones.
  86                         if (traversedContext instanceof ExceptionHandlingFlowContext) {
  87                                 ExceptionHandlingFlowContext exceptionContext = (ExceptionHandlingFlowContext) traversedContext;
  88                                 ReferenceBinding[] caughtExceptions;
  89                                 if ((caughtExceptions = exceptionContext.handledExceptions) != NoExceptions) {
  90                                         int caughtCount = caughtExceptions.length;
  91                                         boolean[] locallyCaught = new boolean[raisedCount]; // at
  92                                                                                                                                                 // most
  93
  94                                         for (int caughtIndex = 0; caughtIndex < caughtCount; caughtIndex++) {
  95                                                 ReferenceBinding caughtException = caughtExceptions[caughtIndex];
  96                                                 for (int raisedIndex = 0; raisedIndex < raisedCount; raisedIndex++) {
  97                                                         TypeBinding raisedException;
  98                                                         if ((raisedException = raisedExceptions[raisedIndex]) != null) {
  99                                                                 switch (Scope.compareTypes(raisedException,
 100                                                                                 caughtException)) {
 101                                                                 case EqualOrMoreSpecific:
 102                                                                         exceptionContext.recordHandlingException(
 103                                                                                         caughtException, flowInfo
 104                                                                                                         .unconditionalInits(),
 105                                                                                         raisedException, location,
 106                                                                                         locallyCaught[raisedIndex]);
 107                                                                         // was already definitely caught ?
 108                                                                         if (!locallyCaught[raisedIndex]) {
 109                                                                                 locallyCaught[raisedIndex] = true;
 110                                                                                 // remember that this exception has been
 111                                                                                 // definitely caught
 112                                                                                 remainingCount--;
 113                                                                         }
 114                                                                         break;
 115                                                                 case MoreGeneric:
 116                                                                         exceptionContext.recordHandlingException(
 117                                                                                         caughtException, flowInfo
 118                                                                                                         .unconditionalInits(),
 119                                                                                         raisedException, location, false);
 120                                                                         // was not caught already per construction
 121                                                                 }
 122                                                         }
 123                                                 }
 124                                         }
 125                                         // remove locally caught exceptions from the remaining ones
 126                                         for (int i = 0; i < raisedCount; i++) {
 127                                                 if (locallyCaught[i]) {
 128                                                         raisedExceptions[i] = null; // removed from the
 129                                                                                                                 // remaining ones.
 130                                                 }
 131                                         }
 132                                 }
 133                                 // method treatment for unchecked exceptions
 134                                 if (exceptionContext.isMethodContext) {
 135                                         for (int i = 0; i < raisedCount; i++) {
 136                                                 TypeBinding raisedException;
 137                                                 if ((raisedException = raisedExceptions[i]) != null) {
 138                                                         if (raisedException.isCompatibleWith(scope
 139                                                                         .getJavaLangRuntimeException())
 140                                                                         || raisedException.isCompatibleWith(scope
 141                                                                                         .getJavaLangError())) {
 142                                                                 remainingCount--;
 143                                                                 raisedExceptions[i] = null;
 144                                                         }
 145                                                 }
 146                                         }
 147                                         // anonymous constructors are allowed to throw any
 148                                         // exceptions (their thrown exceptions
 149                                         // clause will be fixed up later as per JLS 8.6).
 150                                         if (exceptionContext.associatedNode instanceof AbstractMethodDeclaration) {
 151                                                 AbstractMethodDeclaration method = (AbstractMethodDeclaration) exceptionContext.associatedNode;
 152                                                 if (method.isConstructor()
 153                                                                 && method.binding.declaringClass
 154                                                                                 .isAnonymousType()) {
 155
 156                                                         for (int i = 0; i < raisedCount; i++) {
 157                                                                 TypeBinding raisedException;
 158                                                                 if ((raisedException = raisedExceptions[i]) != null) {
 159                                                                         exceptionContext
 160                                                                                         .mergeUnhandledException(raisedException);
 161                                                                 }
 162                                                         }
 163                                                         return; // no need to complain, will fix up
 164                                                                         // constructor exceptions
 165                                                 }
 166                                         }
 167                                         break; // not handled anywhere, thus jump to error handling
 168                                 }
 169                         }
 170                         if (remainingCount == 0)
 171                                 return;
 172
 173                         traversedContext.recordReturnFrom(flowInfo.unconditionalInits());
 174                         if (traversedContext.associatedNode instanceof TryStatement) {
 175                                 flowInfo = flowInfo
 176                                                 .copy()
 177                                                 .addInitializationsFrom(
 178                                                                 ((TryStatement) traversedContext.associatedNode).subRoutineInits);
 179                         }
 180                         traversedContext = traversedContext.parent;
 181                 }
 182                 // if reaches this point, then there are some remaining unhandled
 183                 // exception types.
 184                 nextReport: for (int i = 0; i < raisedCount; i++) {
 185                         TypeBinding exception;
 186                         if ((exception = raisedExceptions[i]) != null) {
 187                                 // only one complaint if same exception declared to be thrown
 188                                 // more than once
 189                                 for (int j = 0; j < i; j++) {
 190                                         if (raisedExceptions[j] == exception)
 191                                                 continue nextReport; // already reported
 192                                 }
 193                                 scope.problemReporter().unhandledException(exception, location);
 194                         }
 195                 }
 196         }
 197
 198         public void checkExceptionHandlers(TypeBinding raisedException,
 199                         ASTNode location, FlowInfo flowInfo, BlockScope scope) {
 200
 201                 // LIGHT-VERSION OF THE EQUIVALENT WITH AN ARRAY OF EXCEPTIONS
 202                 // check that all the argument exception types are handled
 203                 // JDK Compatible implementation - when an exception type is thrown,
 204                 // all related catch blocks are marked as reachable... instead of those
 205                 // only
 206                 // until the point where it is safely handled (Smarter - see comment at
 207                 // the end)
 208                 FlowContext traversedContext = this;
 209                 while (traversedContext != null) {
 210                         ASTNode sub;
 211                         if (((sub = traversedContext.subRoutine()) != null)
 212                                         && sub.cannotReturn()) {
 213                                 // traversing a non-returning subroutine means that all
 214                                 // unhandled
 215                                 // exceptions will actually never get sent...
 216                                 return;
 217                         }
 218
 219                         // filter exceptions that are locally caught from the innermost
 220                         // enclosing
 221                         // try statement to the outermost ones.
 222                         if (traversedContext instanceof ExceptionHandlingFlowContext) {
 223                                 ExceptionHandlingFlowContext exceptionContext = (ExceptionHandlingFlowContext) traversedContext;
 224                                 ReferenceBinding[] caughtExceptions;
 225                                 if ((caughtExceptions = exceptionContext.handledExceptions) != NoExceptions) {
 226                                         boolean definitelyCaught = false;
 227                                         for (int caughtIndex = 0, caughtCount = caughtExceptions.length; caughtIndex < caughtCount; caughtIndex++) {
 228                                                 ReferenceBinding caughtException = caughtExceptions[caughtIndex];
 229                                                 switch (Scope.compareTypes(raisedException,
 230                                                                 caughtException)) {
 231                                                 case EqualOrMoreSpecific:
 232                                                         exceptionContext
 233                                                                         .recordHandlingException(caughtException,
 234                                                                                         flowInfo.unconditionalInits(),
 235                                                                                         raisedException, location,
 236                                                                                         definitelyCaught);
 237                                                         // was it already definitely caught ?
 238                                                         definitelyCaught = true;
 239                                                         break;
 240                                                 case MoreGeneric:
 241                                                         exceptionContext.recordHandlingException(
 242                                                                         caughtException, flowInfo
 243                                                                                         .unconditionalInits(),
 244                                                                         raisedException, location, false);
 245                                                         // was not caught already per construction
 246                                                 }
 247                                         }
 248                                         if (definitelyCaught)
 249                                                 return;
 250                                 }
 251                                 // method treatment for unchecked exceptions
 252                                 if (exceptionContext.isMethodContext) {
 253                                         if (raisedException.isCompatibleWith(scope
 254                                                         .getJavaLangRuntimeException())
 255                                                         || raisedException.isCompatibleWith(scope
 256                                                                         .getJavaLangError()))
 257                                                 return;
 258
 259                                         // anonymous constructors are allowed to throw any
 260                                         // exceptions (their thrown exceptions
 261                                         // clause will be fixed up later as per JLS 8.6).
 262                                         if (exceptionContext.associatedNode instanceof AbstractMethodDeclaration) {
 263                                                 AbstractMethodDeclaration method = (AbstractMethodDeclaration) exceptionContext.associatedNode;
 264                                                 if (method.isConstructor()
 265                                                                 && method.binding.declaringClass
 266                                                                                 .isAnonymousType()) {
 267
 268                                                         exceptionContext
 269                                                                         .mergeUnhandledException(raisedException);
 270                                                         return; // no need to complain, will fix up
 271                                                                         // constructor exceptions
 272                                                 }
 273                                         }
 274                                         break; // not handled anywhere, thus jump to error handling
 275                                 }
 276                         }
 277
 278                         traversedContext.recordReturnFrom(flowInfo.unconditionalInits());
 279                         if (traversedContext.associatedNode instanceof TryStatement) {
 280                                 flowInfo = flowInfo
 281                                                 .copy()
 282                                                 .addInitializationsFrom(
 283                                                                 ((TryStatement) traversedContext.associatedNode).subRoutineInits);
 284                         }
 285                         traversedContext = traversedContext.parent;
 286                 }
 287                 // if reaches this point, then there are some remaining unhandled
 288                 // exception types.
 289                 scope.problemReporter().unhandledException(raisedException, location);
 290         }
 291
 292         public Label continueLabel() {
 293
 294                 return null;
 295         }
 296
 297         /*
 298          * lookup through break labels
 299          */
 300         public FlowContext getTargetContextForBreakLabel(char[] labelName) {
 301
 302                 FlowContext current = this, lastNonReturningSubRoutine = null;
 303                 while (current != null) {
 304                         if (current.isNonReturningContext()) {
 305                                 lastNonReturningSubRoutine = current;
 306                         }
 307                         char[] currentLabelName;
 308                         if (((currentLabelName = current.labelName()) != null)
 309                                         && CharOperation.equals(currentLabelName, labelName)) {
 310                                 if (lastNonReturningSubRoutine == null) {
 311                                         return current;
 312                                 } else {
 313                                         return lastNonReturningSubRoutine;
 314                                 }
 315                         }
 316                         current = current.parent;
 317                 }
 318                 // not found
 319                 return null;
 320         }
 321
 322         /*
 323          * lookup through continue labels
 324          */
 325         public FlowContext getTargetContextForContinueLabel(char[] labelName) {
 326
 327                 FlowContext current = this;
 328                 FlowContext lastContinuable = null;
 329                 FlowContext lastNonReturningSubRoutine = null;
 330
 331                 while (current != null) {
 332                         if (current.isNonReturningContext()) {
 333                                 lastNonReturningSubRoutine = current;
 334                         } else {
 335                                 if (current.isContinuable()) {
 336                                         lastContinuable = current;
 337                                 }
 338                         }
 339
 340                         char[] currentLabelName;
 341                         if ((currentLabelName = current.labelName()) != null
 342                                         && CharOperation.equals(currentLabelName, labelName)) {
 343
 344                                 // matching label found
 345                                 if ((lastContinuable != null)
 346                                                 && (current.associatedNode.concreteStatement() == lastContinuable.associatedNode)) {
 347
 348                                         if (lastNonReturningSubRoutine == null) {
 349                                                 return lastContinuable;
 350                                         } else {
 351                                                 return lastNonReturningSubRoutine;
 352                                         }
 353                                 } else {
 354                                         // label is found, but not a continuable location
 355                                         return NotContinuableContext;
 356                                 }
 357                         }
 358                         current = current.parent;
 359                 }
 360                 // not found
 361                 return null;
 362         }
 363
 364         /*
 365          * lookup a default break through breakable locations
 366          */
 367         public FlowContext getTargetContextForDefaultBreak() {
 368
 369                 FlowContext current = this, lastNonReturningSubRoutine = null;
 370                 while (current != null) {
 371                         if (current.isNonReturningContext()) {
 372                                 lastNonReturningSubRoutine = current;
 373                         }
 374                         if (current.isBreakable() && current.labelName() == null) {
 375                                 if (lastNonReturningSubRoutine == null) {
 376                                         return current;
 377                                 } else {
 378                                         return lastNonReturningSubRoutine;
 379                                 }
 380                         }
 381                         current = current.parent;
 382                 }
 383                 // not found
 384                 return null;
 385         }
 386
 387         /*
 388          * lookup a default continue amongst continuable locations
 389          */
 390         public FlowContext getTargetContextForDefaultContinue() {
 391
 392                 FlowContext current = this, lastNonReturningSubRoutine = null;
 393                 while (current != null) {
 394                         if (current.isNonReturningContext()) {
 395                                 lastNonReturningSubRoutine = current;
 396                         }
 397                         if (current.isContinuable()) {
 398                                 if (lastNonReturningSubRoutine == null) {
 399                                         return current;
 400                                 } else {
 401                                         return lastNonReturningSubRoutine;
 402                                 }
 403                         }
 404                         current = current.parent;
 405                 }
 406                 // not found
 407                 return null;
 408         }
 409
 410         public String individualToString() {
 411
 412                 return "Flow context"; //$NON-NLS-1$
 413         }
 414
 415         public FlowInfo initsOnBreak() {
 416
 417                 return FlowInfo.DEAD_END;
 418         }
 419
 420         public UnconditionalFlowInfo initsOnReturn() {
 421
 422                 return FlowInfo.DEAD_END;
 423         }
 424
 425         public boolean isBreakable() {
 426
 427                 return false;
 428         }
 429
 430         public boolean isContinuable() {
 431
 432                 return false;
 433         }
 434
 435         public boolean isNonReturningContext() {
 436
 437                 return false;
 438         }
 439
 440         public boolean isSubRoutine() {
 441
 442                 return false;
 443         }
 444
 445         public char[] labelName() {
 446
 447                 return null;
 448         }
 449
 450         public void recordBreakFrom(FlowInfo flowInfo) {
 451         }
 452
 453         public void recordContinueFrom(FlowInfo flowInfo) {
 454         }
 455
 456         boolean recordFinalAssignment(VariableBinding variable,
 457                         Reference finalReference) {
 458
 459                 return true; // keep going
 460         }
 461
 462         public void recordReturnFrom(FlowInfo flowInfo) {
 463         }
 464
 465         public void recordSettingFinal(VariableBinding variable,
 466                         Reference finalReference) {
 467
 468                 // for initialization inside looping statement that effectively loops
 469                 FlowContext context = this;
 470                 while (context != null) {
 471                         if (!context.recordFinalAssignment(variable, finalReference)) {
 472                                 break; // no need to keep going
 473                         }
 474                         context = context.parent;
 475                 }
 476         }
 477
 478         void removeFinalAssignmentIfAny(Reference reference) {
 479         }
 480
 481         public ASTNode subRoutine() {
 482
 483                 return null;
 484         }
 485
 486         public String toString() {
 487
 488                 StringBuffer buffer = new StringBuffer();
 489                 FlowContext current = this;
 490                 int parentsCount = 0;
 491                 while ((current = current.parent) != null) {
 492                         parentsCount++;
 493                 }
 494                 FlowContext[] parents = new FlowContext[parentsCount + 1];
 495                 current = this;
 496                 int index = parentsCount;
 497                 while (index >= 0) {
 498                         parents[index--] = current;
 499                         current = current.parent;
 500                 }
 501                 for (int i = 0; i < parentsCount; i++) {
 502                         for (int j = 0; j < i; j++)
 503                                 buffer.append('\t');
 504                         buffer.append(parents[i].individualToString()).append('\n');
 505                 }
 506                 buffer.append('*');
 507                 for (int j = 0; j < parentsCount + 1; j++)
 508                         buffer.append('\t');
 509                 buffer.append(individualToString()).append('\n');
 510                 return buffer.toString();
 511         }
 512 }