/*

  * Licensed to the Apache Software Foundation (ASF) under one

  * or more contributor license agreements.  See the NOTICE file

  * distributed with this work for additional information

  * regarding copyright ownership.  The ASF licenses this file

  * to you under the Apache License, Version 2.0 (the

  * "License"); you may not use this file except in compliance

  * with the License.  You may obtain a copy of the License at

  *

  *     http://www.apache.org/licenses/LICENSE-2.0

  *

  * Unless required by applicable law or agreed to in writing, software

  * distributed under the License is distributed on an "AS IS" BASIS,

  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

  * See the License for the specific language governing permissions and

  * limitations under the License.

  */

 package org.apache.giraph.utils;

 import org.apache.hadoop.conf.Configuration;

 import org.apache.hadoop.fs.FileSystem;

 import org.apache.hadoop.fs.Path;

 import org.apache.log4j.Logger;

 import com.google.common.base.Charsets;

 import com.google.common.io.Closeables;

 import com.google.common.io.Files;

 import java.io.File;

 import java.io.FileFilter;

 import java.io.IOException;

 import java.io.Writer;

 /**

  * Helper class for filesystem operations during testing

  */

 public class FileUtils {

   /** Logger */

   private static final Logger LOG = Logger.getLogger(FileUtils.class);

   /**

    * Utility class should not be instantiatable

    */

   private FileUtils() {

   }

   /**

    * Create a temporary folder that will be removed after the test.

    *

    * @param computationName Used for generating the folder name.

    * @return File object for the directory.

    */

   public static File createTestDir(String computationName)

     throws IOException {

     String systemTmpDir = System.getProperty("java.io.tmpdir");

     long simpleRandomLong = (long) (Long.MAX_VALUE * Math.random());

     File testTempDir = new File(systemTmpDir, "giraph-" +

         computationName + '-' + simpleRandomLong);

     if (!testTempDir.mkdir()) {

       throw new IOException("Could not create " + testTempDir);

     }

     testTempDir.deleteOnExit();

     return testTempDir;

   }

   /**

    * Make a temporary file.

    *

    * @param parent Parent directory.

    * @param name File name.

    * @return File object to temporary file.

    * @throws IOException

    */

   public static File createTempFile(File parent, String name)

     throws IOException {

     return createTestTempFileOrDir(parent, name, false);

   }

   /**

    * Make a temporary directory.

    *

    * @param parent Parent directory.

    * @param name Directory name.

    * @return File object to temporary file.

    * @throws IOException

    */

   public static File createTempDir(File parent, String name)

     throws IOException {

     File dir = createTestTempFileOrDir(parent, name, true);

     if (!dir.delete()) {

       LOG.error("createTempDir: Failed to create directory " + dir);

     }

     return dir;

   }

   /**

    * Create a test temp file or directory.

    *

    * @param parent Parent directory

    * @param name Name of file

    * @param dir Is directory?

    * @return File object

    * @throws IOException

    */

   public static File createTestTempFileOrDir(File parent, String name,

     boolean dir) throws IOException {

     File f = new File(parent, name);

     f.deleteOnExit();

     if (dir && !f.mkdirs()) {

       throw new IOException("Could not make directory " + f);

     }

     return f;

   }

   /**

    * Write lines to a file.

    *

    * @param file File to write lines to

    * @param lines Strings written to the file

    * @throws IOException

    */

   public static void writeLines(File file, String[] lines)

     throws IOException {

     Writer writer = Files.newWriter(file, Charsets.UTF_8);

     try {

       for (String line : lines) {

         writer.write(line);

         writer.write('\n');

       }

     } finally {

       Closeables.close(writer, true);

     }

   }

   /**

    * Recursively delete a directory

    *

    * @param dir Directory to delete

    */

   public static void delete(File dir) {

     if (dir != null) {

       new DeletingVisitor().accept(dir);

     }

   }

   /**

    * Deletes files.

    */

   private static class DeletingVisitor implements FileFilter {

     @Override

     public boolean accept(File f) {

       if (!f.isFile()) {

         if (f.listFiles(this) == null) {

           LOG.error("accept: Failed to list files of " + f);

         }

       }

       if (!f.delete()) {

         LOG.error("accept: Failed to delete file " + f);

       }

       return false;

     }

   }

   /**

    * Helper method to remove a path if it exists.

    *

    * @param conf Configuration to load FileSystem from

    * @param path Path to remove

    * @throws IOException

    */

   public static void deletePath(Configuration conf, String path)

     throws IOException {

     deletePath(conf, new Path(path));

   }

   /**

    * Helper method to remove a path if it exists.

    *

    * @param conf Configuration to load FileSystem from

    * @param path Path to remove

    * @throws IOException

    */

   public static void deletePath(Configuration conf, Path path)

     throws IOException {

     FileSystem fs = FileSystem.get(conf);

     fs.delete(path, true);

   }

 }