IntroduceKindFinder.java

/*
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
 *
 * Copyright 1997-2010 Oracle and/or its affiliates. All rights reserved.
 *
 * Oracle and Java are registered trademarks of Oracle and/or its affiliates.
 * Other names may be trademarks of their respective owners.
 *
 * The contents of this file are subject to the terms of either the GNU
 * General Public License Version 2 only ("GPL") or the Common
 * Development and Distribution License("CDDL") (collectively, the
 * "License"). You may not use this file except in compliance with the
 * License. You can obtain a copy of the License at
 * http://www.netbeans.org/cddl-gplv2.html
 * or nbbuild/licenses/CDDL-GPL-2-CP. See the License for the
 * specific language governing permissions and limitations under the
 * License.  When distributing the software, include this License Header
 * Notice in each file and include the License file at
 * nbbuild/licenses/CDDL-GPL-2-CP.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the GPL Version 2 section of the License file that
 * accompanied this code. If applicable, add the following below the
 * License Header, with the fields enclosed by brackets [] replaced by
 * your own identifying information:
 * "Portions Copyrighted [year] [name of copyright owner]"
 * 
 * If you wish your version of this file to be governed by only the CDDL
 * or only the GPL Version 2, indicate your decision by adding
 * "[Contributor] elects to include this software in this distribution
 * under the [CDDL or GPL Version 2] license." If you do not indicate a
 * single choice of license, a recipient has the option to distribute
 * your version of this file under either the CDDL, the GPL Version 2 or
 * to extend the choice of license to its licensees as provided above.
 * However, if you add GPL Version 2 code and therefore, elected the GPL
 * Version 2 license, then the option applies only if the new code is
 * made subject to such option by the copyright holder.
 * 
 * Contributor(s):
 * 
 * Portions Copyrighted 2007 Sun Microsystems, Inc.
 */
package org.netbeans.modules.ruby.hints.introduce;

import org.netbeans.modules.ruby.ParseTreeVisitor;
import java.util.ArrayList;
import java.util.List;
import org.jrubyparser.ast.Node;
import org.jrubyparser.ast.NodeType;

/**
 * Finder which determines if the given range in the AST represents a valid range for
 * introducing methods, constants, etc - and if so determines -which- IntroduceKinds are eligible.
 * 
 * @author Tor Norbye
 */
class IntroduceKindFinder implements ParseTreeVisitor {
    private boolean seenConstant;
    private boolean seenNonConstant;
    private boolean seenMethod;
    private boolean invalid;
    private boolean simple = true;

    public boolean visit(Node node) {
        switch (node.getNodeType()) {
        // I can't handle these kinds of flow control yet:
        case RETURNNODE:
        // I should be able to handle break and next if the loop which these are referring
        // to are within my code fragment... but how to check that? Needs work! XXX
        case BREAKNODE:
        case NEXTNODE:
        case REDONODE:
        case RETRYNODE:
        // Yield is okay:
        //case YIELDNODE:
            invalid = true;
            break;
            
        case NILNODE:
        case FALSENODE:
        case TRUENODE:
        case ZARRAYNODE:
        case ZEROARGNODE:
        case ARRAYNODE:
        case BIGNUMNODE:
        case FIXNUMNODE:
        case XSTRNODE:
        case STRNODE:
        case REGEXPNODE:
        case FLOATNODE:
        case DREGEXPNODE:
        case DSTRNODE:
        case DXSTRNODE:
        case SYMBOLNODE:
        case EVSTRNODE:
            // constant eligible
            seenConstant = true;
            break;

        case NEWLINENODE:
            // Can't have multiple statements in anything but a method
            seenMethod = true;
            break;

        case DEFNNODE:
        case DEFSNODE:
        case MODULENODE:
        case CLASSNODE:
        case SCLASSNODE:
        case ARGSCATNODE:
        case ARGSNODE:
        case ARGSPUSHNODE:
            invalid = true;
            break;

        // Control flow, assignments etc. imply that it's not an expression, so it would
        // have to be an extract method operation
        case YIELDNODE:
        case WHENNODE:
        case WHILENODE:
        case UNDEFNODE:
        case UNTILNODE:
        case RESCUEBODYNODE:
        case RESCUENODE:
        case ITERNODE:
        case FORNODE:
        case IFNODE:
        case LOCALASGNNODE:
        case DASGNNODE:
        case CONSTDECLNODE:
        case CLASSVARASGNNODE:
        case ATTRASSIGNNODE:
        case CLASSVARDECLNODE:
        case GLOBALASGNNODE:
        case INSTASGNNODE:
        case MULTIPLEASGNNODE:
        case OPASGNANDNODE:
        case OPASGNNODE:
        case OPASGNORNODE:
        case OPELEMENTASGNNODE:
            seenMethod = true;
            break;

        case ANDNODE:
        case ORNODE:
        case NOTNODE:
        case HASHNODE:
        case CALLNODE:
            // What I really want to capture here is that the method
            // is no longer nontrivial - don't offer extract on just a single method
            // identifier etc.
            //simple = false;
            break;

        case FCALLNODE:
        case VCALLNODE:
        case LOCALVARNODE:
        case INSTVARNODE:
        case DVARNODE:
            simple = false;
            seenNonConstant = true;
            break;
        }

        return invalid;
    }

    public boolean unvisit(Node node) {
        return invalid;
    }

    public List<IntroduceKind> getKinds() {
        if (invalid) {
            return null;
        }

        List<IntroduceKind> kinds = new ArrayList<IntroduceKind>();

        if (seenMethod) {
            kinds.add(IntroduceKind.CREATE_METHOD);
            return kinds;
        }

        if (seenConstant) {
            if (!seenNonConstant) {
                kinds.add(IntroduceKind.CREATE_CONSTANT);
            }
            kinds.add(IntroduceKind.CREATE_FIELD);
            kinds.add(IntroduceKind.CREATE_VARIABLE);
        } else if (!simple) {
            kinds.add(IntroduceKind.CREATE_VARIABLE);
            kinds.add(IntroduceKind.CREATE_FIELD);
        }

        return kinds;
    }
}