| /* |
| * Copyright 2014 Google 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.google.gwt.dev.resource.impl; |
| |
| import static java.nio.file.StandardWatchEventKinds.ENTRY_CREATE; |
| import static java.nio.file.StandardWatchEventKinds.ENTRY_DELETE; |
| import static java.nio.file.StandardWatchEventKinds.OVERFLOW; |
| |
| import com.google.gwt.thirdparty.guava.common.collect.ArrayListMultimap; |
| import com.google.gwt.thirdparty.guava.common.collect.Maps; |
| import com.google.gwt.thirdparty.guava.common.collect.Multimap; |
| |
| import java.io.File; |
| import java.io.FileNotFoundException; |
| import java.io.IOException; |
| import java.lang.ref.WeakReference; |
| import java.nio.file.DirectoryStream; |
| import java.nio.file.FileSystems; |
| import java.nio.file.Files; |
| import java.nio.file.NoSuchFileException; |
| import java.nio.file.Path; |
| import java.nio.file.WatchEvent; |
| import java.nio.file.WatchKey; |
| import java.nio.file.WatchService; |
| import java.util.Map; |
| |
| /** |
| * Listens for and accumulates resources for a given root and PathPrefixSet. |
| */ |
| class ResourceAccumulator { |
| |
| private static final boolean WATCH_FILE_CHANGES_DEFAULT = Boolean.parseBoolean( |
| System.getProperty("gwt.watchFileChanges", "true")); |
| |
| private Map<AbstractResource, ResourceResolution> resolutionsByResource; |
| private Multimap<Path, Path> childPathsByParentPath; |
| private Path rootDirectory; |
| private WeakReference<PathPrefixSet> pathPrefixSetRef; |
| private WatchService watchService; |
| private boolean watchFileChanges = WATCH_FILE_CHANGES_DEFAULT; |
| |
| public ResourceAccumulator(Path rootDirectory, PathPrefixSet pathPrefixSet) { |
| this.rootDirectory = rootDirectory; |
| this.pathPrefixSetRef = new WeakReference<PathPrefixSet>(pathPrefixSet); |
| } |
| |
| public boolean isWatchServiceActive() { |
| return watchService != null; |
| } |
| |
| /** |
| * Make sure the resources associated with this directory and pathPrefixSet are up-to-date. |
| */ |
| public void refreshResources() throws IOException { |
| if (isWatchServiceActive()) { |
| refresh(); |
| } else { |
| fullRefresh(); |
| } |
| } |
| |
| public Map<AbstractResource, ResourceResolution> getResources() { |
| return resolutionsByResource; |
| } |
| |
| public void shutdown() throws IOException { |
| // watchService field is not cleared so any attempt to use this class after shutdown will fail. |
| stopWatchService(); |
| } |
| |
| /** |
| * Full refresh clears existing resources and watchers and does a clean refresh. |
| */ |
| private void fullRefresh() throws IOException { |
| resolutionsByResource = Maps.newIdentityHashMap(); |
| childPathsByParentPath = ArrayListMultimap.create(); |
| |
| maybeInitializeWatchService(); |
| |
| onNewDirectory(rootDirectory); |
| } |
| |
| private void maybeInitializeWatchService() throws IOException { |
| if (watchFileChanges) { |
| stopWatchService(); |
| try { |
| watchService = FileSystems.getDefault().newWatchService(); |
| } catch (IOException e) { |
| watchFileChanges = false; |
| } |
| } |
| } |
| |
| private void stopWatchService() throws IOException { |
| if (watchService != null) { |
| watchService.close(); |
| } |
| } |
| |
| private void refresh() throws IOException { |
| while (true) { |
| WatchKey watchKey = watchService.poll(); |
| if (watchKey == null) { |
| return; |
| } |
| |
| Path parentDir = (Path) watchKey.watchable(); |
| |
| for (WatchEvent<?> watchEvent : watchKey.pollEvents()) { |
| WatchEvent.Kind<?> eventKind = watchEvent.kind(); |
| if (eventKind == OVERFLOW) { |
| fullRefresh(); |
| return; |
| } |
| |
| Path child = parentDir.resolve((Path) watchEvent.context()); |
| if (eventKind == ENTRY_CREATE) { |
| onNewPath(child); |
| } else if (eventKind == ENTRY_DELETE) { |
| onRemovedPath(child); |
| } |
| } |
| |
| watchKey.reset(); |
| } |
| } |
| |
| private void onNewPath(Path path) throws IOException { |
| try { |
| if (Files.isHidden(path)) { |
| return; |
| } |
| |
| if (Files.isRegularFile(path)) { |
| onNewFile(path); |
| } else { |
| onNewDirectory(path); |
| } |
| } catch (NoSuchFileException | FileNotFoundException e) { |
| // ignore: might happen, e.g., for temporary files used for "safe writes" by IDEs/editors |
| } |
| } |
| |
| private void onNewDirectory(Path directory) throws IOException { |
| String relativePath = getRelativePath(directory); |
| if (!relativePath.isEmpty() && !getPathPrefixSet().includesDirectory(relativePath)) { |
| return; |
| } |
| |
| if (watchService != null) { |
| // Start watching the directory. |
| directory.register(watchService, ENTRY_CREATE, ENTRY_DELETE); |
| } |
| |
| try (DirectoryStream<Path> stream = Files.newDirectoryStream(directory)) { |
| for (Path child : stream) { |
| childPathsByParentPath.put(directory, child); |
| onNewPath(child); |
| } |
| } |
| } |
| |
| private void onNewFile(Path file) { |
| FileResource resource = toFileResource(file); |
| ResourceResolution resourceResolution = getPathPrefixSet().includesResource(resource.getPath()); |
| if (resourceResolution != null) { |
| resolutionsByResource.put(resource, resourceResolution); |
| } |
| } |
| |
| private void onRemovedPath(Path path) { |
| resolutionsByResource.remove(toFileResource(path)); |
| for (Path child : childPathsByParentPath.get(path)) { |
| onRemovedPath(child); |
| } |
| } |
| |
| private FileResource toFileResource(Path path) { |
| String relativePath = getRelativePath(path); |
| return FileResource.of(relativePath, path.toFile()); |
| } |
| |
| private String getRelativePath(Path directory) { |
| // Make sure that paths are exposed "Unix" style to PathPrefixSet. |
| return rootDirectory.relativize(directory).toString().replace(File.separator, "/"); |
| } |
| |
| private PathPrefixSet getPathPrefixSet() { |
| PathPrefixSet pathPrefixSet = pathPrefixSetRef.get(); |
| // pathPrefixSet can never be null as the life span of this class is bound by it. |
| assert pathPrefixSet != null; |
| return pathPrefixSet; |
| } |
| } |