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.config;
018    
019    import com.intellij.openapi.project.Project;
020    import com.intellij.openapi.util.io.FileUtil;
021    import org.jetbrains.annotations.NotNull;
022    import org.jetbrains.jet.lang.psi.JetFile;
023    import org.jetbrains.k2js.utils.JetFileUtils;
024    
025    import java.io.BufferedReader;
026    import java.io.IOException;
027    import java.io.InputStream;
028    import java.io.InputStreamReader;
029    import java.net.URL;
030    import java.util.*;
031    
032    /**
033     * A helper class to discover a META-INF/services file on the classpath and load the files referenced inside it
034     */
035    public final class MetaInfServices {
036        private MetaInfServices() {
037        }
038    
039        public static List<JetFile> loadServicesFiles(@NotNull String metaInfServicesFile, @NotNull Project project) {
040            List<JetFile> libFiles = new ArrayList<JetFile>();
041            Set<URL> urlsLoaded = new HashSet<URL>();
042            try {
043                Enumeration<URL> resources = MetaInfServices.class.getClassLoader().getResources(metaInfServicesFile);
044                loadLibFiles(resources, urlsLoaded, libFiles, project);
045                resources = Thread.currentThread().getContextClassLoader().getResources(metaInfServicesFile);
046                loadLibFiles(resources, urlsLoaded, libFiles, project);
047            }
048            catch (IOException e) {
049                throw new IllegalStateException(e);
050            }
051            return libFiles;
052        }
053    
054        private static void loadLibFiles(@NotNull Enumeration<URL> resources,
055                @NotNull Set<URL> urlsLoaded,
056                @NotNull List<JetFile> libFiles,
057                @NotNull Project project)
058                throws IOException {
059            while (resources.hasMoreElements()) {
060                URL url = resources.nextElement();
061                if (url != null) {
062                    if (urlsLoaded.add(url)) {
063                        BufferedReader reader = new BufferedReader(new InputStreamReader(url.openStream()));
064                        try {
065                            while (true) {
066                                String line = reader.readLine();
067                                if (line == null) {
068                                    break;
069                                }
070                                else {
071                                    line = line.trim();
072                                    if (line.length() == 0 || line.startsWith("#")) continue;
073                                    // lets try to discover the file
074                                    InputStream stream = loadClasspathResource(line);
075                                    if (stream != null) {
076                                        String text = FileUtil.loadTextAndClose(stream);
077                                        JetFile file = JetFileUtils.createPsiFile(line, text, project);
078                                        libFiles.add(file);
079                                    }
080                                }
081                            }
082                        }
083                        finally {
084                            reader.close();
085                        }
086                    }
087                }
088            }
089        }
090    
091        /**
092         * Tries to load the given resource name on the classpath
093         */
094        public static InputStream loadClasspathResource(String resourceName) {
095            InputStream answer = ClassPathLibraryDefintionsConfig.class.getClassLoader().getResourceAsStream(resourceName);
096            if (answer == null) {
097                answer = Thread.currentThread().getContextClassLoader().getResourceAsStream(resourceName);
098            }
099            return answer;
100        }
101    }