001    /*
002     * Copyright 2010-2013 JetBrains s.r.o.
003     *
004     * Licensed under the Apache License, Version 2.0 (the "License");
005     * you may not use this file except in compliance with the License.
006     * You may obtain a copy of the License at
007     *
008     * http://www.apache.org/licenses/LICENSE-2.0
009     *
010     * Unless required by applicable law or agreed to in writing, software
011     * distributed under the License is distributed on an "AS IS" BASIS,
012     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013     * See the License for the specific language governing permissions and
014     * limitations under the License.
015     */
016    
017    package org.jetbrains.k2js.translate.utils.mutator;
018    
019    import com.google.dart.compiler.backend.js.ast.*;
020    import org.jetbrains.annotations.NotNull;
021    
022    import java.util.List;
023    
024    import static org.jetbrains.k2js.translate.utils.JsAstUtils.convertToStatement;
025    
026    public final class LastExpressionMutator {
027        public static JsStatement mutateLastExpression(@NotNull JsNode node, @NotNull Mutator mutator) {
028            return convertToStatement(new LastExpressionMutator(mutator).apply(node));
029        }
030    
031        @NotNull
032        private final Mutator mutator;
033    
034        private LastExpressionMutator(@NotNull Mutator mutator) {
035            this.mutator = mutator;
036        }
037    
038        //TODO: visitor?
039        //TODO: when expression?
040        @NotNull
041        private JsNode apply(@NotNull JsNode node) {
042            if (node instanceof JsBlock) {
043                return applyToBlock((JsBlock) node);
044            }
045            if (node instanceof JsIf) {
046                return applyToIf((JsIf) node);
047            }
048            if (node instanceof JsExprStmt) {
049                return applyToStatement((JsExprStmt) node);
050            }
051            return mutator.mutate(node);
052        }
053    
054        @NotNull
055        private JsNode applyToStatement(@NotNull JsExprStmt node) {
056            return convertToStatement(apply(node.getExpression()));
057        }
058    
059        @NotNull
060        private JsNode applyToIf(@NotNull JsIf node) {
061            node.setThenStatement(convertToStatement(apply(node.getThenStatement())));
062            JsStatement elseStmt = node.getElseStatement();
063            if (elseStmt != null) {
064                node.setElseStatement(convertToStatement(apply(elseStmt)));
065            }
066            return node;
067        }
068    
069        @NotNull
070        private JsNode applyToBlock(@NotNull JsBlock node) {
071            List<JsStatement> statements = node.getStatements();
072    
073            if (statements.isEmpty()) return node;
074    
075            int size = statements.size();
076            statements.set(size - 1, convertToStatement(apply(statements.get(size - 1))));
077            return node;
078        }
079    }