1 /*
2 * Copyright (C) 2009, Robin Rosenberg <robin.rosenberg@dewire.com>
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.FileNotFoundException;
48 import java.io.IOException;
49 import java.util.ArrayList;
50 import java.util.Collections;
51 import java.util.List;
52
53 import org.eclipse.jgit.lib.Constants;
54 import org.eclipse.jgit.lib.ReflogEntry;
55 import org.eclipse.jgit.lib.ReflogReader;
56 import org.eclipse.jgit.lib.Repository;
57 import org.eclipse.jgit.util.IO;
58 import org.eclipse.jgit.util.RawParseUtils;
59
60 /**
61 * Utility for reading reflog entries
62 */
63 class ReflogReaderImpl implements ReflogReader {
64 private File logName;
65
66 /**
67 * @param db
68 * @param refname
69 */
70 ReflogReaderImpl(Repository db, String refname) {
71 logName = new File(db.getDirectory(), Constants.LOGS + '/' + refname);
72 }
73
74 /* (non-Javadoc)
75 * @see org.eclipse.jgit.internal.storage.file.ReflogReaader#getLastEntry()
76 */
77 public ReflogEntry getLastEntry() throws IOException {
78 return getReverseEntry(0);
79 }
80
81 /* (non-Javadoc)
82 * @see org.eclipse.jgit.internal.storage.file.ReflogReaader#getReverseEntries()
83 */
84 public List<ReflogEntry> getReverseEntries() throws IOException {
85 return getReverseEntries(Integer.MAX_VALUE);
86 }
87
88 /* (non-Javadoc)
89 * @see org.eclipse.jgit.internal.storage.file.ReflogReaader#getReverseEntry(int)
90 */
91 public ReflogEntry getReverseEntry(int number) throws IOException {
92 if (number < 0)
93 throw new IllegalArgumentException();
94
95 final byte[] log;
96 try {
97 log = IO.readFully(logName);
98 } catch (FileNotFoundException e) {
99 return null;
100 }
101
102 int rs = RawParseUtils.prevLF(log, log.length);
103 int current = 0;
104 while (rs >= 0) {
105 rs = RawParseUtils.prevLF(log, rs);
106 if (number == current)
107 return new ReflogEntryImpl(log, rs < 0 ? 0 : rs + 2);
108 current++;
109 }
110 return null;
111 }
112
113 /* (non-Javadoc)
114 * @see org.eclipse.jgit.internal.storage.file.ReflogReaader#getReverseEntries(int)
115 */
116 public List<ReflogEntry> getReverseEntries(int max) throws IOException {
117 final byte[] log;
118 try {
119 log = IO.readFully(logName);
120 } catch (FileNotFoundException e) {
121 return Collections.emptyList();
122 }
123
124 int rs = RawParseUtils.prevLF(log, log.length);
125 List<ReflogEntry> ret = new ArrayList<ReflogEntry>();
126 while (rs >= 0 && max-- > 0) {
127 rs = RawParseUtils.prevLF(log, rs);
128 ReflogEntry entry = new ReflogEntryImpl(log, rs < 0 ? 0 : rs + 2);
129 ret.add(entry);
130 }
131 return ret;
132 }
133 }