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 try
  24  * statements, exception handlers, etc...
  25  */
  26 public class LoopingFlowContext extends SwitchFlowContext {
  27
  28         public Label continueLabel;
  29
  30         public UnconditionalFlowInfo initsOnContinue = FlowInfo.DEAD_END;
  31
  32         Reference finalAssignments[];
  33
  34         VariableBinding finalVariables[];
  35
  36         int assignCount = 0;
  37
  38         Scope associatedScope;
  39
  40         public LoopingFlowContext(FlowContext parent, ASTNode associatedNode,
  41                         Label breakLabel, Label continueLabel, Scope associatedScope) {
  42                 super(parent, associatedNode, breakLabel);
  43                 this.continueLabel = continueLabel;
  44                 this.associatedScope = associatedScope;
  45         }
  46
  47         public void complainOnFinalAssignmentsInLoop(BlockScope scope,
  48                         FlowInfo flowInfo) {
  49                 for (int i = 0; i < assignCount; i++) {
  50                         VariableBinding variable = finalVariables[i];
  51                         if (variable == null)
  52                                 continue;
  53                         boolean complained = false; // remember if have complained on this
  54                                                                                 // final assignment
  55                         if (variable instanceof FieldBinding) {
  56                                 if (flowInfo.isPotentiallyAssigned((FieldBinding) variable)) {
  57                                         complained = true;
  58                                         scope.problemReporter()
  59                                                         .duplicateInitializationOfBlankFinalField(
  60                                                                         (FieldBinding) variable,
  61                                                                         finalAssignments[i]);
  62                                 }
  63                         } else {
  64                                 if (flowInfo
  65                                                 .isPotentiallyAssigned((LocalVariableBinding) variable)) {
  66                                         complained = true;
  67                                         scope.problemReporter()
  68                                                         .duplicateInitializationOfFinalLocal(
  69                                                                         (LocalVariableBinding) variable,
  70                                                                         finalAssignments[i]);
  71                                 }
  72                         }
  73                         // any reference reported at this level is removed from the parent
  74                         // context where it
  75                         // could also be reported again
  76                         if (complained) {
  77                                 FlowContext context = parent;
  78                                 while (context != null) {
  79                                         context.removeFinalAssignmentIfAny(finalAssignments[i]);
  80                                         context = context.parent;
  81                                 }
  82                         }
  83                 }
  84         }
  85
  86         public Label continueLabel() {
  87                 return continueLabel;
  88         }
  89
  90         public String individualToString() {
  91                 StringBuffer buffer = new StringBuffer("Looping flow context"); //$NON-NLS-1$
  92                 buffer
  93                                 .append("[initsOnBreak -").append(initsOnBreak.toString()).append(']'); //$NON-NLS-1$
  94                 buffer
  95                                 .append("[initsOnContinue -").append(initsOnContinue.toString()).append(']'); //$NON-NLS-1$
  96                 return buffer.toString();
  97         }
  98
  99         public boolean isContinuable() {
 100                 return true;
 101         }
 102
 103         public boolean isContinuedTo() {
 104                 return initsOnContinue != FlowInfo.DEAD_END;
 105         }
 106
 107         public void recordContinueFrom(FlowInfo flowInfo) {
 108
 109                 if (!flowInfo.isReachable())
 110                         return;
 111                 if (initsOnContinue == FlowInfo.DEAD_END) {
 112                         initsOnContinue = flowInfo.copy().unconditionalInits();
 113                 } else {
 114                         initsOnContinue = initsOnContinue.mergedWith(flowInfo
 115                                         .unconditionalInits());
 116                 }
 117                 ;
 118         }
 119
 120         boolean recordFinalAssignment(VariableBinding binding,
 121                         Reference finalAssignment) {
 122                 // do not consider variables which are defined inside this loop
 123                 if (binding instanceof LocalVariableBinding) {
 124                         Scope scope = ((LocalVariableBinding) binding).declaringScope;
 125                         while ((scope = scope.parent) != null) {
 126                                 if (scope == associatedScope)
 127                                         return false;
 128                         }
 129                 }
 130                 if (assignCount == 0) {
 131                         finalAssignments = new Reference[5];
 132                         finalVariables = new VariableBinding[5];
 133                 } else {
 134                         if (assignCount == finalAssignments.length)
 135                                 System.arraycopy(finalAssignments, 0,
 136                                                 (finalAssignments = new Reference[assignCount * 2]), 0,
 137                                                 assignCount);
 138                         System.arraycopy(finalVariables, 0,
 139                                         (finalVariables = new VariableBinding[assignCount * 2]), 0,
 140                                         assignCount);
 141                 }
 142                 ;
 143                 finalAssignments[assignCount] = finalAssignment;
 144                 finalVariables[assignCount++] = binding;
 145                 return true;
 146         }
 147
 148         void removeFinalAssignmentIfAny(Reference reference) {
 149                 for (int i = 0; i < assignCount; i++) {
 150                         if (finalAssignments[i] == reference) {
 151                                 finalAssignments[i] = null;
 152                                 finalVariables[i] = null;
 153                                 return;
 154                         }
 155                 }
 156         }
 157 }