001/*
002 * Copyright (C) 2012 eXo Platform SAS.
003 *
004 * This is free software; you can redistribute it and/or modify it
005 * under the terms of the GNU Lesser General Public License as
006 * published by the Free Software Foundation; either version 2.1 of
007 * the License, or (at your option) any later version.
008 *
009 * This software is distributed in the hope that it will be useful,
010 * but WITHOUT ANY WARRANTY; without even the implied warranty of
011 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
012 * Lesser General Public License for more details.
013 *
014 * You should have received a copy of the GNU Lesser General Public
015 * License along with this software; if not, write to the Free
016 * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
017 * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
018 */
019package org.crsh.lang.impl.groovy.ast;
020
021import org.codehaus.groovy.ast.ASTNode;
022import org.codehaus.groovy.ast.ClassHelper;
023import org.codehaus.groovy.ast.ClassNode;
024import org.codehaus.groovy.ast.FieldNode;
025import org.codehaus.groovy.ast.MethodNode;
026import org.codehaus.groovy.ast.Parameter;
027import org.codehaus.groovy.ast.stmt.BlockStatement;
028import org.codehaus.groovy.ast.stmt.ReturnStatement;
029import org.codehaus.groovy.ast.stmt.Statement;
030import org.codehaus.groovy.control.CompilePhase;
031import org.codehaus.groovy.control.SourceUnit;
032import org.codehaus.groovy.transform.ASTTransformation;
033import org.codehaus.groovy.transform.GroovyASTTransformation;
034import org.crsh.lang.impl.groovy.command.GroovyScriptCommand;
035
036import java.lang.reflect.Modifier;
037import java.util.List;
038
039/**
040 * <p>A transformer that tags a CRaSH script class when it has an explicit return statement.
041 * Indeed Groovy script last statement are returned by default and this value is sometimes
042 * not desirable in CRaSH script commands unless they are explicitly returned by the script.</p>
043 *
044 * @author Julien Viet
045 */
046@GroovyASTTransformation(phase= CompilePhase.SEMANTIC_ANALYSIS)
047public class ScriptLastStatementTransformer implements ASTTransformation {
048
049  /** . */
050  public static final String FIELD_NAME = "org_crsh_has_explicit_return";
051
052  /** . */
053  private static final ClassNode GROOVY_SCRIPT_COMMAND = ClassHelper.make(GroovyScriptCommand.class);
054
055  @Override
056  public void visit(ASTNode[] nodes, SourceUnit source) {
057    for (ClassNode classNode : source.getAST().getClasses()) {
058      if (classNode.isDerivedFrom(GROOVY_SCRIPT_COMMAND)) {
059        MethodNode run = classNode.getMethod("run", new Parameter[0]);
060        Statement code = run.getCode();
061        if (code instanceof BlockStatement) {
062          BlockStatement block = (BlockStatement)code;
063          List<Statement> statements = block.getStatements();
064          int size = statements.size();
065          if (size > 0) {
066            Statement last = statements.get(size - 1);
067            if (last instanceof ReturnStatement) {
068              classNode.addField(new FieldNode(
069                  FIELD_NAME,
070                  Modifier.PUBLIC | Modifier.STATIC,
071                  ClassHelper.Boolean_TYPE,
072                  classNode,
073                  null));
074            }
075          }
076        }
077      }
078    }
079  }
080}