1 /*
2 * Copyright (C) 2009, Google Inc.
3 * and other copyright owners as documented in the project's IP log.
4 *
5 * This program and the accompanying materials are made available
6 * under the terms of the Eclipse Distribution License v1.0 which
7 * accompanies this distribution, is reproduced below, and is
8 * available at http://www.eclipse.org/org/documents/edl-v10.php
9 *
10 * All rights reserved.
11 *
12 * Redistribution and use in source and binary forms, with or
13 * without modification, are permitted provided that the following
14 * conditions are met:
15 *
16 * - Redistributions of source code must retain the above copyright
17 * notice, this list of conditions and the following disclaimer.
18 *
19 * - Redistributions in binary form must reproduce the above
20 * copyright notice, this list of conditions and the following
21 * disclaimer in the documentation and/or other materials provided
22 * with the distribution.
23 *
24 * - Neither the name of the Eclipse Foundation, Inc. nor the
25 * names of its contributors may be used to endorse or promote
26 * products derived from this software without specific prior
27 * written permission.
28 *
29 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
30 * CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
31 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
32 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
33 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
34 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
35 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
36 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
37 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
38 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
39 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
40 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
41 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
42 */
43
44 package org.eclipse.jgit.internal.storage.file;
45
46 import java.io.File;
47 import java.io.IOException;
48
49 import org.eclipse.jgit.lib.Constants;
50 import org.eclipse.jgit.util.FS;
51 import org.eclipse.jgit.util.FileUtils;
52
53 /**
54 * Keeps track of a {@link org.eclipse.jgit.internal.storage.file.PackFile}'s
55 * associated <code>.keep</code> file.
56 */
57 public class PackLock {
58 private final File keepFile;
59
60 /**
61 * Create a new lock for a pack file.
62 *
63 * @param packFile
64 * location of the <code>pack-*.pack</code> file.
65 * @param fs
66 * the filesystem abstraction used by the repository.
67 */
68 public PackLock(File packFile, FS fs) {
69 final File p = packFile.getParentFile();
70 final String n = packFile.getName();
71 keepFile = new File(p, n.substring(0, n.length() - 5) + ".keep"); //$NON-NLS-1$
72 }
73
74 /**
75 * Create the <code>pack-*.keep</code> file, with the given message.
76 *
77 * @param msg
78 * message to store in the file.
79 * @return true if the keep file was successfully written; false otherwise.
80 * @throws java.io.IOException
81 * the keep file could not be written.
82 */
83 public boolean lock(String msg) throws IOException {
84 if (msg == null)
85 return false;
86 if (!msg.endsWith("\n")) //$NON-NLS-1$
87 msg += "\n"; //$NON-NLS-1$
88 final LockFile lf = new LockFile(keepFile);
89 if (!lf.lock())
90 return false;
91 lf.write(Constants.encode(msg));
92 return lf.commit();
93 }
94
95 /**
96 * Remove the <code>.keep</code> file that holds this pack in place.
97 *
98 * @throws java.io.IOException
99 * if deletion of .keep file failed
100 */
101 public void unlock() throws IOException {
102 FileUtils.delete(keepFile);
103 }
104 }