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;

import java.util.Stack;

import org.momut.ooas.ast.expressions.Expression;

import org.momut.ooas.ast.expressions.ExpressionKind;

import org.momut.ooas.ast.expressions.IdentifierExpression;

import org.momut.ooas.ast.identifiers.IdentifierKind;

import org.momut.ooas.ast.identifiers.MethodIdentifier;

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

import org.momut.ooas.ast.types.FunctionType;

import org.momut.ooas.ast.types.OoActionSystemType;

import org.momut.ooas.parser.ParserMessage;

import org.momut.ooas.parser.ParserState;

/// <summary>

/// This visitor scans all methods and decides whether they are pure, i.e. there is no state-update.

/// </summary>

public final class OoaMethodPureClassifierVisitor extends OoaCompleteAstTraversalVisitor

{

        Stack<MethodIdentifier> currentMethod = new Stack<MethodIdentifier>();

        @Override

        public void visit(MethodIdentifier methodIdentifier)

        {

                currentMethod.push(methodIdentifier);

                ((FunctionType)currentMethod.peek().type()).SetIsPureFunction(true); // assume is true..

                super.visit(currentMethod.peek());

                if (((FunctionType)currentMethod.peek().type()).isPureFunction())

                {

                        m_ParserState.AddMessage(

                                        new ParserMessage(m_ParserState.filename, methodIdentifier.line(),

                                                        methodIdentifier.column(), String.format("Found pure method: %s",

                                                                        methodIdentifier.tokenText())));

                } else

                        m_ParserState.AddMessage(

                                        new ParserMessage(m_ParserState.filename, methodIdentifier.line(),

                                                        methodIdentifier.column(), String.format("Found extended method: %s",

                                                                        methodIdentifier.tokenText())));

                currentMethod.pop();

        }

        @Override

        public void visit(OoActionSystemType systemType)

        {

                boolean functionPure = false; //introduce variable with save value

                if (currentMethod.size() > 0 && currentMethod.peek() != null) //if we are determining the pureness...

                {

                        functionPure = ((FunctionType)currentMethod.peek().type()).isPureFunction(); //...save the current value

                }

                super.visit(systemType); // go down in recursion

                if ( currentMethod.size() > 0 && currentMethod.peek() != null) //but restore old pureness!

                {

                        ((FunctionType)currentMethod.peek().type()).SetIsPureFunction(functionPure);

                }

        }

        @Override

        public void visit(Assignment assignment)

        {

                boolean assignmentPure = true;

                if (currentMethod.size() > 0 && currentMethod.peek() != null)

                {

                        for (Expression x: assignment.places())

                        {

                                if (x.kind() != ExpressionKind.Identifier)

                                        assignmentPure = false;

                                else if (((IdentifierExpression)x).identifier().kind() == IdentifierKind.AttributeIdentifier)

                                        assignmentPure = false;

                        }

                        boolean functionPure = assignmentPure && ((FunctionType)currentMethod.peek().type()).isPureFunction();

                        ((FunctionType)currentMethod.peek().type()).SetIsPureFunction(functionPure);

                }

                super.visit(assignment);

        }

        public OoaMethodPureClassifierVisitor(ParserState aState)

        {

                super (aState);

        }

}