net.sourceforge.phpeclipse/src/net/sourceforge/phpdt/internal/compiler/flow/FlowInfo.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.Statement;
  14 import net.sourceforge.phpdt.internal.compiler.lookup.BlockScope;
  15 import net.sourceforge.phpdt.internal.compiler.lookup.FieldBinding;
  16 import net.sourceforge.phpdt.internal.compiler.lookup.LocalVariableBinding;
  17
  18 public abstract class FlowInfo {
  19         public static final UnconditionalFlowInfo DeadEnd = new UnconditionalFlowInfo(); // Represents a dead branch status of initialization
  20 abstract public UnconditionalFlowInfo addInitializationsFrom(UnconditionalFlowInfo otherInits);
  21 abstract public UnconditionalFlowInfo addPotentialInitializationsFrom(UnconditionalFlowInfo otherInits);
  22 public FlowInfo asNegatedCondition() {
  23         return this;
  24 }
  25 public boolean complainIfUnreachable(Statement statement, BlockScope scope) {
  26         // Report an error if necessary
  27
  28         return false;
  29 }
  30 public static FlowInfo conditional(FlowInfo initsWhenTrue, FlowInfo initsWhenFalse){
  31         // if (initsWhenTrue.equals(initsWhenFalse)) return initsWhenTrue; -- could optimize if #equals is defined
  32         return new ConditionalFlowInfo(initsWhenTrue, initsWhenFalse);
  33 }
  34 abstract public FlowInfo copy();
  35 public static UnconditionalFlowInfo initial(int maxFieldCount) {
  36         UnconditionalFlowInfo info = new UnconditionalFlowInfo();
  37         info.maxFieldCount = maxFieldCount;
  38         return info;
  39 }
  40 abstract public FlowInfo initsWhenFalse();
  41 abstract public FlowInfo initsWhenTrue();
  42 final public boolean isDeadEnd() {
  43         return this == DeadEnd;
  44 }
  45 /**
  46  * Check status of definite assignment for a field.
  47  */
  48  abstract public boolean isDefinitelyAssigned(FieldBinding field);
  49 /**
  50  * Check status of definite assignment for a local.
  51  */
  52 public abstract boolean isDefinitelyAssigned(LocalVariableBinding local);
  53 abstract public boolean isFakeReachable();
  54 /**
  55  * Check status of potential assignment for a field.
  56  */
  57  abstract public boolean isPotentiallyAssigned(FieldBinding field);
  58 /**
  59  * Check status of potential assignment for a local variable.
  60  */
  61  abstract public boolean isPotentiallyAssigned(LocalVariableBinding field);
  62 /**
  63  * Record a field got definitely assigned.
  64  */
  65 abstract public void markAsDefinitelyAssigned(FieldBinding field);
  66 /**
  67  * Record a local got definitely assigned.
  68  */
  69 abstract public void markAsDefinitelyAssigned(LocalVariableBinding local);
  70 /**
  71  * Clear the initialization info for a field
  72  */
  73 abstract public void markAsDefinitelyNotAssigned(FieldBinding field);
  74 /**
  75  * Clear the initialization info for a local variable
  76  */
  77 abstract public void markAsDefinitelyNotAssigned(LocalVariableBinding local);
  78 abstract public FlowInfo markAsFakeReachable(boolean isFakeReachable);
  79 abstract public UnconditionalFlowInfo mergedWith(UnconditionalFlowInfo otherInits);
  80 public String toString(){
  81         if (this == DeadEnd){
  82                 return "FlowInfo.DeadEnd"; //$NON-NLS-1$
  83         }
  84         return super.toString();
  85 }
  86 abstract public UnconditionalFlowInfo unconditionalInits();
  87 }