net.sourceforge.phpeclipse/src/net/sourceforge/phpdt/internal/compiler/ast/Case.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.ast;
  12
  13 import net.sourceforge.phpdt.internal.compiler.IAbstractSyntaxTreeVisitor;
  14 import net.sourceforge.phpdt.internal.compiler.codegen.CaseLabel;
  15 import net.sourceforge.phpdt.internal.compiler.codegen.CodeStream;
  16 import net.sourceforge.phpdt.internal.compiler.flow.FlowContext;
  17 import net.sourceforge.phpdt.internal.compiler.flow.FlowInfo;
  18 import net.sourceforge.phpdt.internal.compiler.impl.Constant;
  19 import net.sourceforge.phpdt.internal.compiler.lookup.BlockScope;
  20 import net.sourceforge.phpdt.internal.compiler.lookup.TypeBinding;
  21
  22 public class Case extends Statement {
  23
  24         public Expression constantExpression;
  25         public CaseLabel targetLabel;
  26         public Case(int sourceStart, Expression constantExpression) {
  27                 this.constantExpression = constantExpression;
  28                 this.sourceEnd = constantExpression.sourceEnd;
  29                 this.sourceStart = sourceStart;
  30         }
  31
  32         public FlowInfo analyseCode(
  33                 BlockScope currentScope,
  34                 FlowContext flowContext,
  35                 FlowInfo flowInfo) {
  36
  37                 if (constantExpression.constant == NotAConstant)
  38                         currentScope.problemReporter().caseExpressionMustBeConstant(constantExpression);
  39
  40                 this.constantExpression.analyseCode(currentScope, flowContext, flowInfo);
  41                 return flowInfo;
  42         }
  43
  44         /**
  45          * Case code generation
  46          *
  47          */
  48         public void generateCode(BlockScope currentScope, CodeStream codeStream) {
  49
  50                 if ((bits & IsReachableMASK) == 0) {
  51                         return;
  52                 }
  53                 int pc = codeStream.position;
  54                 targetLabel.place();
  55                 codeStream.recordPositionsFrom(pc, this.sourceStart);
  56         }
  57
  58         public void resolve(BlockScope scope) {
  59
  60                 // error....use resolveCase....
  61                 throw new NullPointerException();
  62         }
  63
  64         public Constant resolveCase(
  65                 BlockScope scope,
  66                 TypeBinding testTb,
  67                 SwitchStatement switchStatement) {
  68
  69                 // add into the collection of cases of the associated switch statement
  70                 switchStatement.cases[switchStatement.caseCount++] = this;
  71                 TypeBinding caseTb = constantExpression.resolveType(scope);
  72                 if (caseTb == null || testTb == null)
  73                         return null;
  74                 if (constantExpression.isConstantValueOfTypeAssignableToType(caseTb, testTb))
  75                         return constantExpression.constant;
  76                 if (BlockScope.areTypesCompatible(caseTb, testTb))
  77                         return constantExpression.constant;
  78                 scope.problemReporter().typeMismatchErrorActualTypeExpectedType(
  79                         constantExpression,
  80                         caseTb,
  81                         testTb);
  82                 return null;
  83         }
  84
  85         public String toString(int tab) {
  86
  87                 String s = tabString(tab);
  88                 s = s + "case " + constantExpression.toStringExpression() + " : "; //$NON-NLS-1$ //$NON-NLS-2$
  89                 return s;
  90         }
  91
  92         public void traverse(
  93                 IAbstractSyntaxTreeVisitor visitor,
  94                 BlockScope blockScope) {
  95
  96                 if (visitor.visit(this, blockScope)) {
  97                         constantExpression.traverse(visitor, blockScope);
  98                 }
  99                 visitor.endVisit(this, blockScope);
 100         }
 101 }