net.sourceforge.phpeclipse/src/net/sourceforge/phpdt/internal/compiler/flow/LoopingFlowContext.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.internal.compiler.ast.ASTNode;
  14 import net.sourceforge.phpdt.internal.compiler.ast.Reference;
  15 import net.sourceforge.phpdt.internal.compiler.codegen.Label;
  16 import net.sourceforge.phpdt.internal.compiler.lookup.BlockScope;
  17 import net.sourceforge.phpdt.internal.compiler.lookup.FieldBinding;
  18 import net.sourceforge.phpdt.internal.compiler.lookup.LocalVariableBinding;
  19 import net.sourceforge.phpdt.internal.compiler.lookup.Scope;
  20 import net.sourceforge.phpdt.internal.compiler.lookup.VariableBinding;
  21
  22 /**
  23  * Reflects the context of code analysis, keeping track of enclosing
  24  *      try statements, exception handlers, etc...
  25  */
  26 public class LoopingFlowContext extends SwitchFlowContext {
  27
  28         public Label continueLabel;
  29         public UnconditionalFlowInfo initsOnContinue = FlowInfo.DEAD_END;
  30         Reference finalAssignments[];
  31         VariableBinding finalVariables[];
  32         int assignCount = 0;
  33         Scope associatedScope;
  34
  35         public LoopingFlowContext(
  36                 FlowContext parent,
  37                 ASTNode associatedNode,
  38                 Label breakLabel,
  39                 Label continueLabel,
  40                 Scope associatedScope) {
  41                 super(parent, associatedNode, breakLabel);
  42                 this.continueLabel = continueLabel;
  43                 this.associatedScope = associatedScope;
  44         }
  45
  46         public void complainOnFinalAssignmentsInLoop(
  47                 BlockScope scope,
  48                 FlowInfo flowInfo) {
  49                 for (int i = 0; i < assignCount; i++) {
  50                         VariableBinding variable = finalVariables[i];
  51                         if (variable == null) continue;
  52                         boolean complained = false; // remember if have complained on this final assignment
  53                         if (variable instanceof FieldBinding) {
  54                                 if (flowInfo.isPotentiallyAssigned((FieldBinding) variable)) {
  55                                         complained = true;
  56                                         scope.problemReporter().duplicateInitializationOfBlankFinalField(
  57                                                 (FieldBinding) variable,
  58                                                 finalAssignments[i]);
  59                                 }
  60                         } else {
  61                                 if (flowInfo.isPotentiallyAssigned((LocalVariableBinding) variable)) {
  62                                         complained = true;
  63                                         scope.problemReporter().duplicateInitializationOfFinalLocal(
  64                                                 (LocalVariableBinding) variable,
  65                                                 finalAssignments[i]);
  66                                 }
  67                         }
  68                         // any reference reported at this level is removed from the parent context where it
  69                         // could also be reported again
  70                         if (complained) {
  71                                 FlowContext context = parent;
  72                                 while (context != null) {
  73                                         context.removeFinalAssignmentIfAny(finalAssignments[i]);
  74                                         context = context.parent;
  75                                 }
  76                         }
  77                 }
  78         }
  79
  80         public Label continueLabel() {
  81                 return continueLabel;
  82         }
  83
  84         public String individualToString() {
  85                 StringBuffer buffer = new StringBuffer("Looping flow context"); //$NON-NLS-1$
  86                 buffer.append("[initsOnBreak -").append(initsOnBreak.toString()).append(']'); //$NON-NLS-1$
  87                 buffer.append("[initsOnContinue -").append(initsOnContinue.toString()).append(']'); //$NON-NLS-1$
  88                 return buffer.toString();
  89         }
  90
  91         public boolean isContinuable() {
  92                 return true;
  93         }
  94
  95         public boolean isContinuedTo() {
  96                 return initsOnContinue != FlowInfo.DEAD_END;
  97         }
  98
  99         public void recordContinueFrom(FlowInfo flowInfo) {
 100
 101                 if (!flowInfo.isReachable()) return;
 102                 if (initsOnContinue == FlowInfo.DEAD_END) {
 103                         initsOnContinue = flowInfo.copy().unconditionalInits();
 104                 } else {
 105                         initsOnContinue = initsOnContinue.mergedWith(flowInfo.unconditionalInits());
 106                 };
 107         }
 108
 109         boolean recordFinalAssignment(
 110                 VariableBinding binding,
 111                 Reference finalAssignment) {
 112                 // do not consider variables which are defined inside this loop
 113                 if (binding instanceof LocalVariableBinding) {
 114                         Scope scope = ((LocalVariableBinding) binding).declaringScope;
 115                         while ((scope = scope.parent) != null) {
 116                                 if (scope == associatedScope)
 117                                         return false;
 118                         }
 119                 }
 120                 if (assignCount == 0) {
 121                         finalAssignments = new Reference[5];
 122                         finalVariables = new VariableBinding[5];
 123                 } else {
 124                         if (assignCount == finalAssignments.length)
 125                                 System.arraycopy(
 126                                         finalAssignments,
 127                                         0,
 128                                         (finalAssignments = new Reference[assignCount * 2]),
 129                                         0,
 130                                         assignCount);
 131                         System.arraycopy(
 132                                 finalVariables,
 133                                 0,
 134                                 (finalVariables = new VariableBinding[assignCount * 2]),
 135                                 0,
 136                                 assignCount);
 137                 };
 138                 finalAssignments[assignCount] = finalAssignment;
 139                 finalVariables[assignCount++] = binding;
 140                 return true;
 141         }
 142
 143         void removeFinalAssignmentIfAny(Reference reference) {
 144                 for (int i = 0; i < assignCount; i++) {
 145                         if (finalAssignments[i] == reference) {
 146                                 finalAssignments[i] = null;
 147                                 finalVariables[i] = null;
 148                                 return;
 149                         }
 150                 }
 151         }
 152 }