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.ast.IScope;

import org.momut.ooas.ast.statements.Block;

import org.momut.ooas.ast.statements.NondetBlock;

import org.momut.ooas.ast.statements.PrioBlock;

import org.momut.ooas.ast.statements.SeqBlock;

import org.momut.ooas.ast.statements.Statement;

import org.momut.ooas.ast.statements.StatementKind;

import org.momut.ooas.parser.ParserState;

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

import org.momut.ooas.visitors.OoaCompleteAstTraversalVisitor;

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;

        }

}