| /* |
| * 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.solr.util; |
| |
| import java.io.File; |
| import java.io.FileInputStream; |
| import java.io.FileNotFoundException; |
| import java.io.FilenameFilter; |
| import java.io.IOException; |
| import java.io.InputStream; |
| import java.nio.file.Files; |
| import java.util.ArrayList; |
| import java.util.Arrays; |
| import java.util.Collection; |
| import java.util.HashSet; |
| import java.util.List; |
| import java.util.Set; |
| |
| |
| /** |
| * |
| * @since solr 1.3 |
| */ |
| public class VersionedFile |
| { |
| /* Open the latest version of a file... fileName if that exists, or |
| * the last fileName.* after being sorted lexicographically. |
| * Older versions of the file are deleted (and queued for deletion if |
| * that fails). |
| */ |
| public static InputStream getLatestFile(String dirName, String fileName) throws FileNotFoundException |
| { |
| Collection<File> oldFiles=null; |
| final String prefix = fileName+'.'; |
| File f = new File(dirName, fileName); |
| InputStream is = null; |
| |
| // there can be a race between checking for a file and opening it... |
| // the user may have just put a new version in and deleted an old version. |
| // try multiple times in a row. |
| for (int retry=0; retry<10 && is==null; retry++) { |
| try { |
| if (!f.exists()) { |
| File dir = new File(dirName); |
| String[] names = dir.list(new FilenameFilter() { |
| @Override |
| public boolean accept(File dir, String name) { |
| return name.startsWith(prefix); |
| } |
| }); |
| Arrays.sort(names); |
| f = new File(dir, names[names.length-1]); |
| oldFiles = new ArrayList<>(); |
| for (int i=0; i<names.length-1; i++) { |
| oldFiles.add(new File(dir, names[i])); |
| } |
| } |
| |
| is = new FileInputStream(f); |
| } catch (Exception e) { |
| // swallow exception for now |
| } |
| } |
| |
| // allow exception to be thrown from the final try. |
| if (is == null) { |
| is = new FileInputStream(f); |
| } |
| |
| // delete old files only after we have successfully opened the newest |
| if (oldFiles != null) { |
| delete(oldFiles); |
| } |
| |
| return is; |
| } |
| |
| private static final Set<File> deleteList = new HashSet<>(); |
| private static synchronized void delete(Collection<File> files) { |
| synchronized (deleteList) { |
| deleteList.addAll(files); |
| List<File> deleted = new ArrayList<>(); |
| for (File df : deleteList) { |
| try { |
| try { |
| Files.deleteIfExists(df.toPath()); |
| } catch (IOException cause) { |
| // TODO: should this class care if a file couldn't be deleted? |
| // this just emulates previous behavior, where only SecurityException would be handled. |
| } |
| // deleteList.remove(df); |
| deleted.add(df); |
| } catch (SecurityException e) { |
| if (!df.exists()) { |
| deleted.add(df); |
| } |
| } |
| } |
| deleteList.removeAll(deleted); |
| } |
| } |
| } |