| /* |
| * 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.lucene.mockfile; |
| |
| import java.io.IOException; |
| import java.nio.file.CopyOption; |
| import java.nio.file.FileSystem; |
| import java.nio.file.Files; |
| import java.nio.file.Path; |
| import java.nio.file.attribute.BasicFileAttributeView; |
| import java.nio.file.attribute.BasicFileAttributes; |
| import java.util.HashMap; |
| import java.util.Map; |
| |
| /** |
| * FileSystem that (imperfectly) acts like windows. |
| * <p> |
| * Currently this filesystem only prevents deletion of open files. |
| */ |
| public class WindowsFS extends HandleTrackingFS { |
| // This map also supports fileKey -> Path -> counts |
| // which is important to effectively support renames etc. |
| // in the rename case we have to transfer ownership but need to make sure we only transfer ownership for |
| // the path we rename ie. hardlinks will still resolve to the same key |
| final Map<Object,Map<Path, Integer>> openFiles = new HashMap<>(); |
| // TODO: try to make this as realistic as possible... it depends e.g. how you |
| // open files, if you map them, etc, if you can delete them (Uwe knows the rules) |
| |
| // TODO: add case-insensitivity |
| |
| /** |
| * Create a new instance, wrapping the delegate filesystem to |
| * act like Windows. |
| * @param delegate delegate filesystem to wrap. |
| */ |
| public WindowsFS(FileSystem delegate) { |
| super("windows://", delegate); |
| } |
| |
| /** |
| * Returns file "key" (e.g. inode) for the specified path |
| */ |
| private Object getKey(Path existing) throws IOException { |
| BasicFileAttributeView view = Files.getFileAttributeView(existing, BasicFileAttributeView.class); |
| BasicFileAttributes attributes = view.readAttributes(); |
| return attributes.fileKey(); |
| } |
| |
| @Override |
| protected void onOpen(Path path, Object stream) throws IOException { |
| synchronized (openFiles) { |
| final Object key = getKey(path); |
| // we have to read the key under the lock otherwise me might leak the openFile handle |
| // if we concurrently delete or move this file. |
| Map<Path, Integer> pathMap = openFiles.computeIfAbsent(key, k -> new HashMap<>()); |
| pathMap.put(path, pathMap.computeIfAbsent(path, p -> 0).intValue() +1); |
| } |
| } |
| |
| @Override |
| protected void onClose(Path path, Object stream) throws IOException { |
| Object key = getKey(path); // here we can read this outside of the lock |
| synchronized (openFiles) { |
| Map<Path, Integer> pathMap = openFiles.get(key); |
| assert pathMap != null; |
| assert pathMap.containsKey(path); |
| Integer v = pathMap.get(path); |
| if (v != null) { |
| if (v.intValue() == 1) { |
| pathMap.remove(path); |
| } else { |
| v = Integer.valueOf(v.intValue()-1); |
| pathMap.put(path, v); |
| } |
| } |
| if (pathMap.isEmpty()) { |
| openFiles.remove(key); |
| } |
| } |
| } |
| |
| private Object getKeyOrNull(Path path) { |
| try { |
| return getKey(path); |
| } catch (Exception ignore) { |
| // we don't care if the file doesn't exist |
| } |
| return null; |
| } |
| |
| /** |
| * Checks that it's ok to delete {@code Path}. If the file |
| * is still open, it throws IOException("access denied"). |
| */ |
| private void checkDeleteAccess(Path path) throws IOException { |
| Object key = getKeyOrNull(path); |
| if (key != null) { |
| synchronized(openFiles) { |
| if (openFiles.containsKey(key)) { |
| throw new IOException("access denied: " + path); |
| } |
| } |
| } |
| } |
| |
| @Override |
| public void delete(Path path) throws IOException { |
| synchronized (openFiles) { |
| checkDeleteAccess(path); |
| super.delete(path); |
| } |
| } |
| |
| @Override |
| public void move(Path source, Path target, CopyOption... options) throws IOException { |
| synchronized (openFiles) { |
| checkDeleteAccess(source); |
| Object key = getKeyOrNull(target); |
| super.move(source, target, options); |
| if (key != null) { |
| Object newKey = getKey(target); |
| if (newKey.equals(key) == false) { |
| // we need to transfer ownership here if we have open files on this file since the getKey() method will |
| // return a different i-node next time we call it with the target path and our onClose method will |
| // trip an assert |
| Map<Path, Integer> map = openFiles.get(key); |
| if (map != null) { |
| Integer v = map.remove(target); |
| if (v != null) { |
| Map<Path, Integer> pathIntegerMap = openFiles.computeIfAbsent(newKey, k -> new HashMap<>()); |
| Integer existingValue = pathIntegerMap.getOrDefault(target, 0); |
| pathIntegerMap.put(target, existingValue + v); |
| } |
| if (map.isEmpty()) { |
| openFiles.remove(key); |
| } |
| } |
| } |
| } |
| } |
| } |
| |
| @Override |
| public boolean deleteIfExists(Path path) throws IOException { |
| synchronized (openFiles) { |
| checkDeleteAccess(path); |
| return super.deleteIfExists(path); |
| } |
| } |
| } |