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      1 /*
      2  * Copyright (C) 2017 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 package com.android.car.test.utils;
     18 
     19 import android.annotation.Nullable;
     20 import android.os.SystemClock;
     21 import java.io.File;
     22 import java.io.IOException;
     23 import java.nio.file.FileVisitResult;
     24 import java.nio.file.Files;
     25 import java.nio.file.Path;
     26 import java.nio.file.SimpleFileVisitor;
     27 import java.nio.file.attribute.BasicFileAttributes;
     28 
     29 /**
     30  * A utility class that creates a temporary directory.
     31  * The directory, and any files contained within, are automatically deleted when calling close().
     32  *
     33  * Example usage:
     34  *
     35  * try (TemporaryDirectory tf = new TemporaryDirectory("myTest")) {
     36  *     ...
     37  * } // directory gets deleted here
     38  */
     39 public class TemporaryDirectory implements AutoCloseable {
     40     private Path mDirectory;
     41 
     42     private static final class DeletingVisitor extends SimpleFileVisitor<Path> {
     43         FileVisitResult consume(Path path) throws IOException {
     44             Files.delete(path);
     45             return FileVisitResult.CONTINUE;
     46         }
     47 
     48         @Override
     49         public FileVisitResult visitFile(Path path, BasicFileAttributes basicFileAttributes)
     50                 throws IOException {
     51             return consume(path);
     52         }
     53 
     54         @Override
     55         public FileVisitResult postVisitDirectory(Path path, IOException e)
     56                 throws IOException {
     57             return consume(path);
     58         }
     59     }
     60 
     61     private static final SimpleFileVisitor<Path> DELETE = new DeletingVisitor();
     62 
     63     TemporaryDirectory(Path directory) throws IOException {
     64         mDirectory = Files.createDirectory(directory);
     65     }
     66 
     67     public TemporaryDirectory(@Nullable String prefix) throws IOException {
     68         if (prefix == null) {
     69             prefix = TemporaryDirectory.class.getSimpleName();
     70         }
     71         prefix += String.valueOf(SystemClock.elapsedRealtimeNanos());
     72 
     73         mDirectory = Files.createTempDirectory(prefix);
     74     }
     75 
     76     @Override
     77     public void close() throws Exception {
     78         Files.walkFileTree(mDirectory, DELETE);
     79     }
     80 
     81     public File getDirectory() {
     82         return mDirectory.toFile();
     83     }
     84 
     85     public Path getPath() { return mDirectory; }
     86 
     87     public TemporaryDirectory getSubdirectory(String name) throws IOException {
     88         return new TemporaryDirectory(mDirectory.resolve(name));
     89     }
     90 }
     91