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 /** {@inheritDoc} */
78 @Override
79 public ReflogEntry getLastEntry() throws IOException {
80 return getReverseEntry(0);
81 }
82
83 /* (non-Javadoc)
84 * @see org.eclipse.jgit.internal.storage.file.ReflogReaader#getReverseEntries()
85 */
86 /** {@inheritDoc} */
87 @Override
88 public List<ReflogEntry> getReverseEntries() throws IOException {
89 return getReverseEntries(Integer.MAX_VALUE);
90 }
91
92 /* (non-Javadoc)
93 * @see org.eclipse.jgit.internal.storage.file.ReflogReaader#getReverseEntry(int)
94 */
95 /** {@inheritDoc} */
96 @Override
97 public ReflogEntry getReverseEntry(int number) throws IOException {
98 if (number < 0)
99 throw new IllegalArgumentException();
100
101 final byte[] log;
102 try {
103 log = IO.readFully(logName);
104 } catch (FileNotFoundException e) {
105 if (logName.exists()) {
106 throw e;
107 }
108 return null;
109 }
110
111 int rs = RawParseUtils.prevLF(log, log.length);
112 int current = 0;
113 while (rs >= 0) {
114 rs = RawParseUtils.prevLF(log, rs);
115 if (number == current)
116 return new ReflogEntryImpl(log, rs < 0 ? 0 : rs + 2);
117 current++;
118 }
119 return null;
120 }
121
122 /* (non-Javadoc)
123 * @see org.eclipse.jgit.internal.storage.file.ReflogReaader#getReverseEntries(int)
124 */
125 /** {@inheritDoc} */
126 @Override
127 public List<ReflogEntry> getReverseEntries(int max) throws IOException {
128 final byte[] log;
129 try {
130 log = IO.readFully(logName);
131 } catch (FileNotFoundException e) {
132 if (logName.exists()) {
133 throw e;
134 }
135 return Collections.emptyList();
136 }
137
138 int rs = RawParseUtils.prevLF(log, log.length);
139 List<ReflogEntry> ret = new ArrayList<>();
140 while (rs >= 0 && max-- > 0) {
141 rs = RawParseUtils.prevLF(log, rs);
142 ReflogEntry entry = new ReflogEntryImpl(log, rs < 0 ? 0 : rs + 2);
143 ret.add(entry);
144 }
145 return ret;
146 }
147 }