| /* |
| * Copyright 2012-present Facebook, Inc. |
| * |
| * Licensed 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 com.facebook.buck.util; |
| |
| import com.google.common.base.Preconditions; |
| import com.google.common.collect.ImmutableSet; |
| import com.google.common.collect.Maps; |
| import com.google.common.eventbus.EventBus; |
| |
| import java.io.Closeable; |
| import java.io.IOException; |
| import java.nio.file.FileVisitResult; |
| import java.nio.file.LinkOption; |
| import java.nio.file.Path; |
| import java.nio.file.SimpleFileVisitor; |
| import java.nio.file.StandardWatchEventKinds; |
| import java.nio.file.WatchEvent; |
| import java.nio.file.WatchKey; |
| import java.nio.file.WatchService; |
| import java.nio.file.attribute.BasicFileAttributes; |
| import java.util.Map; |
| |
| /** |
| * Watches a ProjectFilesystem for file changes using a given WatchService. |
| * Change events are posted to a given EventBus when postEvents are called unless the affected files are |
| * contained within the given excludeDirectories. |
| */ |
| public class ProjectFilesystemWatcher implements Closeable { |
| |
| private final WatchService watchService; // TODO(user): use intellij file watching? |
| private final Map<WatchKey,Path> keys; |
| private final EventBus eventBus; |
| private final ProjectFilesystem filesystem; |
| private final ImmutableSet<String> ignoredPrefixes; |
| |
| public ProjectFilesystemWatcher(ProjectFilesystem filesystem, |
| EventBus fileChangeEventBus, |
| ImmutableSet<String> excludeDirectories, |
| WatchService watchService) throws IOException { |
| this.filesystem = Preconditions.checkNotNull(filesystem); |
| this.ignoredPrefixes = Preconditions.checkNotNull(excludeDirectories); |
| this.eventBus = Preconditions.checkNotNull(fileChangeEventBus); |
| this.watchService = Preconditions.checkNotNull(watchService); |
| this.keys = Maps.newHashMap(); |
| registerAll(filesystem.getRootPath()); |
| } |
| |
| /** Post filesystem events to eventBus */ |
| public void postEvents() throws IOException { |
| WatchKey key; |
| while((key = watchService.poll()) != null) { |
| Path dir = keys.get(key); |
| if (dir == null) { |
| continue; // Ignored or unknown directory. |
| } |
| for (final WatchEvent<?> event : key.pollEvents()) { |
| if (filesystem.isPathChangeEvent(event)) { |
| |
| // Check against ignored directories. |
| Path name = (Path) event.context(); |
| final Path child = dir.resolve(name); |
| if (shouldIgnore(child)) { |
| continue; |
| } |
| |
| // If directory is created, watch its children. |
| if (filesystem.isDirectory(child, LinkOption.NOFOLLOW_LINKS)) { |
| if (event.kind() == StandardWatchEventKinds.ENTRY_CREATE) { |
| registerAll(child); |
| } |
| continue; // TODO(user): post events about directories? |
| } |
| |
| // Path returned by event.context() is relative to key directory, so return resolved |
| // child Path instead to allow clients to access the full, absolute Path correctly. |
| eventBus.post(new WatchEvent<Path>(){ |
| |
| @Override |
| @SuppressWarnings("unchecked") // Needed for conversion from Kind<?> to Kind<Path> |
| public Kind<Path> kind() { |
| return (Kind<Path>) event.kind(); |
| } |
| |
| @Override |
| public int count() { |
| return event.count(); |
| } |
| |
| @Override |
| public Path context() { |
| return child; |
| } |
| }); |
| |
| } else { |
| eventBus.post(event); |
| } |
| } |
| |
| // Reset key and remove from set if directory no longer accessible |
| if (!key.reset()) { |
| keys.remove(key); |
| } |
| } |
| } |
| |
| private boolean shouldIgnore(Path path) { |
| Path normalizedPath = path.normalize(); |
| for (String prefix : ignoredPrefixes) { |
| if (normalizedPath.startsWith(prefix)) { |
| return true; |
| } |
| } |
| return false; |
| } |
| |
| /** |
| * Register the given directory with the WatchService. |
| */ |
| private void register(Path dir) throws IOException { |
| WatchKey key = dir.register(watchService, |
| StandardWatchEventKinds.ENTRY_CREATE, |
| StandardWatchEventKinds.ENTRY_DELETE, |
| StandardWatchEventKinds.ENTRY_MODIFY); |
| keys.put(key, dir); |
| } |
| |
| /** |
| * Register the given directory, and all its sub-directories, with the |
| * WatchService, unless it's an ignored sub-tree. |
| */ |
| private void registerAll(final Path start) throws IOException { |
| filesystem.walkFileTree(start, new SimpleFileVisitor<Path>() { |
| @Override |
| public FileVisitResult preVisitDirectory(Path dir, BasicFileAttributes attributes) |
| throws IOException { |
| if (shouldIgnore(dir)) { |
| return FileVisitResult.SKIP_SUBTREE; |
| } |
| register(dir); |
| return FileVisitResult.CONTINUE; |
| } |
| }); |
| } |
| |
| @Override |
| public void close() throws IOException { |
| watchService.close(); |
| } |
| } |