1 /*
2  * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4  *
5  * This code is free software; you can redistribute it and/or modify it
6  * under the terms of the GNU General Public License version 2 only, as
7  * published by the Free Software Foundation.  Oracle designates this
8  * particular file as subject to the "Classpath" exception as provided
9  * by Oracle in the LICENSE file that accompanied this code.
10  *
11  * This code is distributed in the hope that it will be useful, but WITHOUT
12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
14  * version 2 for more details (a copy is included in the LICENSE file that
15  * accompanied this code).
16  *
17  * You should have received a copy of the GNU General Public License version
18  * 2 along with this work; if not, write to the Free Software Foundation,
19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20  *
21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22  * or visit www.oracle.com if you need additional information or have any
23  * questions.
24  */
25 package java.io;
26 
27 import java.util.*;
28 import java.io.File;
29 
30 /**
31  * This class holds a set of filenames to be deleted on VM exit through a shutdown hook.
32  * A set is used both to prevent double-insertion of the same file as well as offer
33  * quick removal.
34  */
35 
36 class DeleteOnExitHook {
37     private static LinkedHashSet<String> files = new LinkedHashSet<>();
38     static {
39         // BEGIN Android-changed: Use Runtime.addShutdownHook() rather than SharedSecrets.
40         Runtime.getRuntime().addShutdownHook(new Thread() {
41             public void run() {
42                 runHooks();
43             }
44         });
45         // END Android-changed: Use Runtime.addShutdownHook() rather than SharedSecrets.
46     }
47 
DeleteOnExitHook()48     private DeleteOnExitHook() {}
49 
add(String file)50     static synchronized void add(String file) {
51         if(files == null) {
52             // DeleteOnExitHook is running. Too late to add a file
53             throw new IllegalStateException("Shutdown in progress");
54         }
55 
56         files.add(file);
57     }
58 
runHooks()59     static void runHooks() {
60         LinkedHashSet<String> theFiles;
61 
62         synchronized (DeleteOnExitHook.class) {
63             theFiles = files;
64             files = null;
65         }
66 
67         ArrayList<String> toBeDeleted = new ArrayList<>(theFiles);
68 
69         // reverse the list to maintain previous jdk deletion order.
70         // Last in first deleted.
71         Collections.reverse(toBeDeleted);
72         for (String filename : toBeDeleted) {
73             (new File(filename)).delete();
74         }
75     }
76 }
77