| /* |
| * Copyright 2022 Google LLC |
| * |
| * 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.android.libraries.mobiledatadownload.file.openers; |
| |
| import android.net.Uri; |
| import com.google.android.libraries.mobiledatadownload.file.OpenContext; |
| import com.google.android.libraries.mobiledatadownload.file.Opener; |
| import com.google.android.libraries.mobiledatadownload.file.SynchronousFileStorage; |
| import com.google.android.libraries.mobiledatadownload.file.common.internal.Exceptions; |
| import java.io.IOException; |
| import java.util.ArrayList; |
| import java.util.List; |
| |
| /** |
| * Deletes the file or directory at the given URI recursively. This behaves similarly to {@link |
| * SynchronousFileStorage#deleteRecursively} except as described in the following paragraph. |
| * |
| * <p>If an IO exception occurs attempting to read, open, or delete any file under the given |
| * directory, this method skips that file and continues. All such exceptions are collected and, |
| * after attempting to delete all files, an {@code IOException} is thrown containing those |
| * exceptions as {@linkplain Throwable#getSuppressed() suppressed exceptions}. |
| * |
| * <p>WARNING: this opener suffers from the following caveats and should be used with caution: |
| * |
| * <ul> |
| * <li>Directory tree traversal is not an atomic operation |
| * <li>There are no special considerations for symlinks, meaning the opener could get caught in a |
| * recursive directory loop (i.e. a directory that contains a symlink to itself) |
| * </ul> |
| * |
| * <p>Usage: <code> |
| * storage.open(uri, RecursiveDeleteOpener.create()); |
| * </code> |
| */ |
| public final class RecursiveDeleteOpener implements Opener<Void> { |
| private RecursiveDeleteOpener() {} |
| |
| public static RecursiveDeleteOpener create() { |
| return new RecursiveDeleteOpener(); |
| } |
| |
| @Override |
| public Void open(OpenContext openContext) throws IOException { |
| List<IOException> exceptions = new ArrayList<>(); |
| deleteRecursively(openContext.storage(), openContext.encodedUri(), exceptions); |
| if (!exceptions.isEmpty()) { |
| throw Exceptions.combinedIOException("Failed to delete one or more files", exceptions); |
| } |
| |
| return null; // for Void return type |
| } |
| |
| private static void deleteRecursively( |
| SynchronousFileStorage storage, Uri uri, List<IOException> exceptions) { |
| try { |
| if (storage.isDirectory(uri)) { |
| for (Uri child : storage.children(uri)) { |
| deleteRecursively(storage, child, exceptions); |
| } |
| storage.deleteDirectory(uri); |
| } else { |
| storage.deleteFile(uri); |
| } |
| } catch (IOException e) { |
| exceptions.add(e); |
| } |
| } |
| } |