net.sourceforge.phpeclipse/src/net/sourceforge/phpdt/internal/compiler/flow/LoopingFlowContext.java

   1 /*******************************************************************************
   2  * Copyright (c) 2000, 2001, 2002 International Business Machines Corp. and others.
   3  * All rights reserved. This program and the accompanying materials
   4  * are made available under the terms of the Common Public License v0.5
   5  * which accompanies this distribution, and is available at
   6  * http://www.eclipse.org/legal/cpl-v05.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.internal.compiler.ast.AstNode;
  14 import net.sourceforge.phpdt.internal.compiler.ast.NameReference;
  15 import net.sourceforge.phpdt.internal.compiler.ast.Reference;
  16 import net.sourceforge.phpdt.internal.compiler.codegen.Label;
  17 import net.sourceforge.phpdt.internal.compiler.lookup.BlockScope;
  18 import net.sourceforge.phpdt.internal.compiler.lookup.FieldBinding;
  19 import net.sourceforge.phpdt.internal.compiler.lookup.LocalVariableBinding;
  20 import net.sourceforge.phpdt.internal.compiler.lookup.Scope;
  21 import net.sourceforge.phpdt.internal.compiler.lookup.VariableBinding;
  22
  23 /**
  24  * Reflects the context of code analysis, keeping track of enclosing
  25  *      try statements, exception handlers, etc...
  26  */
  27 public class LoopingFlowContext extends SwitchFlowContext {
  28         public Label continueLabel;
  29         public UnconditionalFlowInfo initsOnContinue = FlowInfo.DeadEnd;
  30         Reference finalAssignments[];
  31         VariableBinding finalVariables[];
  32         int assignCount = 0;
  33         Scope associatedScope;
  34         public LoopingFlowContext(
  35                 FlowContext parent,
  36                 AstNode associatedNode,
  37                 Label breakLabel,
  38                 Label continueLabel,
  39                 Scope associatedScope) {
  40                 super(parent, associatedNode, breakLabel);
  41                 this.continueLabel = continueLabel;
  42                 this.associatedScope = associatedScope;
  43         }
  44
  45         public void complainOnFinalAssignmentsInLoop(
  46                 BlockScope scope,
  47                 FlowInfo flowInfo) {
  48                 for (int i = 0; i < assignCount; i++) {
  49                         VariableBinding variable;
  50                         if ((variable = finalVariables[i]) != null) {
  51                                 boolean complained; // remember if have complained on this final assignment
  52                                 if (variable instanceof FieldBinding) {
  53                                         if (complained = flowInfo.isPotentiallyAssigned((FieldBinding) variable)) {
  54                                                 scope.problemReporter().duplicateInitializationOfBlankFinalField(
  55                                                         (FieldBinding) variable,
  56                                                         (NameReference) finalAssignments[i]);
  57                                         }
  58                                 } else {
  59                                         if (complained =
  60                                                 flowInfo.isPotentiallyAssigned((LocalVariableBinding) variable)) {
  61                                                 scope.problemReporter().duplicateInitializationOfFinalLocal(
  62                                                         (LocalVariableBinding) variable,
  63                                                         (NameReference) finalAssignments[i]);
  64                                         }
  65                                 }
  66                                 // any reference reported at this level is removed from the parent context where it
  67                                 // could also be reported again
  68                                 if (complained) {
  69                                         FlowContext context = parent;
  70                                         while (context != null) {
  71                                                 context.removeFinalAssignmentIfAny(finalAssignments[i]);
  72                                                 context = context.parent;
  73                                         }
  74                                 }
  75                         }
  76                 }
  77         }
  78
  79         public Label continueLabel() {
  80                 return continueLabel;
  81         }
  82
  83         public String individualToString() {
  84                 return "Looping flow context"; //$NON-NLS-1$
  85         }
  86
  87         public boolean isContinuable() {
  88                 return true;
  89         }
  90
  91         public boolean isContinuedTo() {
  92                 return initsOnContinue != FlowInfo.DeadEnd;
  93         }
  94
  95         public void recordContinueFrom(FlowInfo flowInfo) {
  96                 if (initsOnContinue == FlowInfo.DeadEnd) {
  97                         initsOnContinue = flowInfo.copy().unconditionalInits();
  98                 } else {
  99                         // ignore if not really reachable (1FKEKRP)
 100                         if (flowInfo.isFakeReachable())
 101                                 return;
 102                         initsOnContinue.mergedWith(flowInfo.unconditionalInits());
 103                 };
 104         }
 105
 106         boolean recordFinalAssignment(
 107                 VariableBinding binding,
 108                 Reference finalAssignment) {
 109                 // do not consider variables which are defined inside this loop
 110                 if (binding instanceof LocalVariableBinding) {
 111                         Scope scope = ((LocalVariableBinding) binding).declaringScope;
 112                         while ((scope = scope.parent) != null) {
 113                                 if (scope == associatedScope)
 114                                         return false;
 115                         }
 116                 }
 117                 if (assignCount == 0) {
 118                         finalAssignments = new Reference[5];
 119                         finalVariables = new VariableBinding[5];
 120                 } else {
 121                         if (assignCount == finalAssignments.length)
 122                                 System.arraycopy(
 123                                         finalAssignments,
 124                                         0,
 125                                         (finalAssignments = new Reference[assignCount * 2]),
 126                                         0,
 127                                         assignCount);
 128                         System.arraycopy(
 129                                 finalVariables,
 130                                 0,
 131                                 (finalVariables = new VariableBinding[assignCount * 2]),
 132                                 0,
 133                                 assignCount);
 134                 };
 135                 finalAssignments[assignCount] = finalAssignment;
 136                 finalVariables[assignCount++] = binding;
 137                 return true;
 138         }
 139
 140         void removeFinalAssignmentIfAny(Reference reference) {
 141                 for (int i = 0; i < assignCount; i++) {
 142                         if (finalAssignments[i] == reference) {
 143                                 finalAssignments[i] = null;
 144                                 finalVariables[i] = null;
 145                                 return;
 146                         }
 147                 }
 148         }
 149 }