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