BreakStatement.java

/*******************************************************************************
 * Copyright (c) 2000, 2004 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials 
 * are made available under the terms of the Common Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/cpl-v10.html
 * 
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.jdt.internal.compiler.ast;

import org.eclipse.jdt.internal.compiler.ASTVisitor;
import org.eclipse.jdt.internal.compiler.flow.*;
import org.eclipse.jdt.internal.compiler.lookup.*;

public class BreakStatement extends BranchStatement {
	
	public BreakStatement(char[] label, int sourceStart, int e) {
		super(label, sourceStart, e);
	}

	public FlowInfo analyseCode(
		BlockScope currentScope,
		FlowContext flowContext,
		FlowInfo flowInfo) {

		// here requires to generate a sequence of finally blocks invocations depending corresponding
		// to each of the traversed try statements, so that execution will terminate properly.

		// lookup the label, this should answer the returnContext
		FlowContext targetContext = (label == null) 
			? flowContext.getTargetContextForDefaultBreak()
			: flowContext.getTargetContextForBreakLabel(label);

		if (targetContext == null) {
			if (label == null) {
				currentScope.problemReporter().invalidBreak(this);
			} else {
				currentScope.problemReporter().undefinedLabel(this); 
			}
			return flowInfo; // pretend it did not break since no actual target
		}
		
		targetLabel = targetContext.breakLabel();
		FlowContext traversedContext = flowContext;
		int subIndex = 0, maxSub = 5;
		subroutines = new SubRoutineStatement[maxSub];
		
		do {
			SubRoutineStatement sub;
			if ((sub = traversedContext.subRoutine()) != null) {
				if (subIndex == maxSub) {
					System.arraycopy(subroutines, 0, (subroutines = new SubRoutineStatement[maxSub*=2]), 0, subIndex); // grow
				}
				subroutines[subIndex++] = sub;
				if (sub.isSubRoutineEscaping()) {
					break;
				}
			}
			traversedContext.recordReturnFrom(flowInfo.unconditionalInits());

			ASTNode node;
			if ((node = traversedContext.associatedNode) instanceof TryStatement) {
				TryStatement tryStatement = (TryStatement) node;
				flowInfo.addInitializationsFrom(tryStatement.subRoutineInits); // collect inits			
			} else if (traversedContext == targetContext) {
				// only record break info once accumulated through subroutines, and only against target context
				targetContext.recordBreakFrom(flowInfo);
				break;
			}
		} while ((traversedContext = traversedContext.parent) != null);
		
		// resize subroutines
		if (subIndex != maxSub) {
			System.arraycopy(subroutines, 0, (subroutines = new SubRoutineStatement[subIndex]), 0, subIndex);
		}
		return FlowInfo.DEAD_END;
	}
	
	public StringBuffer printStatement(int tab, StringBuffer output) {

		printIndent(tab, output).append("break "); //$NON-NLS-1$
		if (label != null) output.append(label);
		return output.append(';');
	}
	
	public void traverse(
		ASTVisitor visitor,
		BlockScope blockscope) {

		visitor.visit(this, blockscope);
		visitor.endVisit(this, blockscope);
	}
}