OoasTools

/**

  *

  *                      OOAS Compiler

  *

  *       Copyright 2015, AIT Austrian Institute of Technology.

  * This code is based on the C# Version of the OOAS Compiler, which is

  * copyright 2015 by the Institute of Software Technology, Graz University

  * of Technology with portions copyright by the AIT Austrian Institute of

  * Technology. All rights reserved.

  *

  * SEE THE "LICENSE" FILE FOR THE TERMS UNDER WHICH THIS FILE IS PROVIDED.

  *

  * If you modify the file please update the list of contributors below to in-

  * clude your name. Please also stick to the coding convention of using TABs

  * to do the basic (block-level) indentation and spaces for anything after

  * that. (Enable the display of special chars and it should be pretty obvious

  * what this means.) Also, remove all trailing whitespace.

  *

  * Contributors:

  *               Willibald Krenn (AIT)

  *               Stephan Zimmerer (AIT)

  *               Markus Demetz (AIT)

  *               Christoph Czurda (AIT)

  *

  */

package org.momut.ooas.visitors.optimisation;

import java.util.LinkedList;

import org.momut.ooas.utils.exceptions.InternalCompilerException;

public final class OoaJoinSequentialCompositionBlocksVisitor extends OoaCompleteAstTraversalVisitor {

	@Override

	public void visit(SeqBlock seqBlock) {

		// do all the children first.

		super.visit(seqBlock);

		checkScope(seqBlock);

		// now see whether we can join a child-seq block

		boolean didSomeWork = false;

		final LinkedList<Statement> newList = new LinkedList<>();

		for (final Statement s: seqBlock.statements()) {

			if (s.kind() == StatementKind.SeqBlock && ((Block)s).isSimpleBlock()) {

				final SeqBlock child = (SeqBlock)s;

				if (child.GetParentScope() != seqBlock)

					throw new InternalCompilerException("Internal Error: AST structure error.");

				// now add all the statements of seqblock to the current seqblock

				for (final Statement childS: child.statements()) {

					if (childS instanceof IScope)

						((IScope)childS).SetParentScope(seqBlock);

					newList.add(childS);

				}

				didSomeWork = true;

			} else

				newList.add(s);

		}

		if (didSomeWork) {

			m_changes = true;

			seqBlock.SetStatements(newList);

		}

	}

	@Override

	public void visit(NondetBlock nondetBlock) {

		super.visit(nondetBlock);

		checkScope(nondetBlock);

	}

	@Override

	public void visit(PrioBlock prioBlock) {

		super.visit(prioBlock);

		checkScope(prioBlock);

	}

	private final void checkScope(Block aBlock) {

		for (final Statement element: aBlock.statements())

			if (element instanceof IScope) {

				final IScope child = (IScope) element;

				if (child.GetParentScope() != aBlock)

					throw new InternalCompilerException("Internal Error: AST structure error.");

			}

	}

	private boolean m_changes = false;

	public OoaJoinSequentialCompositionBlocksVisitor(ParserState aState) {

		super(aState);

	}

	public boolean changedAst() {

		return m_changes;

	}

}