repo/org.ibex.tool/src/org/eclipse/jdt/internal/compiler/ast/LabeledStatement.java

   1 /*******************************************************************************
   2  * Copyright (c) 2000, 2004 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 org.eclipse.jdt.internal.compiler.ast;
  12
  13 import org.eclipse.jdt.internal.compiler.ASTVisitor;
  14 import org.eclipse.jdt.internal.compiler.codegen.*;
  15 import org.eclipse.jdt.internal.compiler.flow.*;
  16 import org.eclipse.jdt.internal.compiler.lookup.*;
  17
  18 public class LabeledStatement extends Statement {
  19
  20         public Statement statement;
  21         public char[] label;
  22         public Label targetLabel;
  23
  24         // for local variables table attributes
  25         int mergedInitStateIndex = -1;
  26
  27         /**
  28          * LabeledStatement constructor comment.
  29          */
  30         public LabeledStatement(char[] label, Statement statement, int sourceStart, int sourceEnd) {
  31
  32                 this.statement = statement;
  33                 // remember useful empty statement
  34                 if (statement instanceof EmptyStatement) statement.bits |= IsUsefulEmptyStatementMASK;
  35                 this.label = label;
  36                 this.sourceStart = sourceStart;
  37                 this.sourceEnd = sourceEnd;
  38         }
  39
  40         public FlowInfo analyseCode(
  41                 BlockScope currentScope,
  42                 FlowContext flowContext,
  43                 FlowInfo flowInfo) {
  44
  45                 // need to stack a context to store explicit label, answer inits in case of normal completion merged
  46                 // with those relative to the exit path from break statement occurring inside the labeled statement.
  47                 if (statement == null) {
  48                         return flowInfo;
  49                 } else {
  50                         LabelFlowContext labelContext;
  51                         FlowInfo mergedInfo =
  52                                 statement
  53                                         .analyseCode(
  54                                                 currentScope,
  55                                                 (labelContext =
  56                                                         new LabelFlowContext(
  57                                                                 flowContext,
  58                                                                 this,
  59                                                                 label,
  60                                                                 (targetLabel = new Label()),
  61                                                                 currentScope)),
  62                                                 flowInfo)
  63                                         .mergedWith(labelContext.initsOnBreak);
  64                         mergedInitStateIndex =
  65                                 currentScope.methodScope().recordInitializationStates(mergedInfo);
  66                         return mergedInfo;
  67                 }
  68         }
  69
  70         public ASTNode concreteStatement() {
  71
  72                 // return statement.concreteStatement(); // for supporting nested labels:   a:b:c: someStatement (see 21912)
  73                 return statement;
  74         }
  75
  76         /**
  77          * Code generation for labeled statement
  78          *
  79          * may not need actual source positions recording
  80          *
  81          * @param currentScope org.eclipse.jdt.internal.compiler.lookup.BlockScope
  82          * @param codeStream org.eclipse.jdt.internal.compiler.codegen.CodeStream
  83          */
  84         public void generateCode(BlockScope currentScope, CodeStream codeStream) {
  85
  86                 int pc = codeStream.position;
  87                 if (targetLabel != null) {
  88                         targetLabel.initialize(codeStream);
  89                         if (statement != null) {
  90                                 statement.generateCode(currentScope, codeStream);
  91                         }
  92                         targetLabel.place();
  93                 }
  94                 // May loose some local variable initializations : affecting the local variable attributes
  95                 if (mergedInitStateIndex != -1) {
  96                         codeStream.removeNotDefinitelyAssignedVariables(currentScope, mergedInitStateIndex);
  97                         codeStream.addDefinitelyAssignedVariables(currentScope, mergedInitStateIndex);
  98                 }
  99                 codeStream.recordPositionsFrom(pc, this.sourceStart);
 100         }
 101
 102         public StringBuffer printStatement(int tab, StringBuffer output) {
 103
 104                 printIndent(tab, output).append(label).append(": "); //$NON-NLS-1$
 105                 if (this.statement == null)
 106                         output.append(';');
 107                 else
 108                         this.statement.printStatement(0, output);
 109                 return output;
 110         }
 111
 112         public void resolve(BlockScope scope) {
 113
 114                 if (this.statement != null) {
 115                         this.statement.resolve(scope);
 116                 }
 117         }
 118
 119
 120         public void traverse(
 121                 ASTVisitor visitor,
 122                 BlockScope blockScope) {
 123
 124                 if (visitor.visit(this, blockScope)) {
 125                         if (this.statement != null) this.statement.traverse(visitor, blockScope);
 126                 }
 127                 visitor.endVisit(this, blockScope);
 128         }
 129 }