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1   /*
2    * Copyright (C) 2009, Constantine Plotnikov <constantine.plotnikov@gmail.com>
3    * Copyright (C) 2009, Google Inc.
4    * Copyright (C) 2009, JetBrains s.r.o.
5    * and other copyright owners as documented in the project's IP log.
6    *
7    * This program and the accompanying materials are made available
8    * under the terms of the Eclipse Distribution License v1.0 which
9    * accompanies this distribution, is reproduced below, and is
10   * available at http://www.eclipse.org/org/documents/edl-v10.php
11   *
12   * All rights reserved.
13   *
14   * Redistribution and use in source and binary forms, with or
15   * without modification, are permitted provided that the following
16   * conditions are met:
17   *
18   * - Redistributions of source code must retain the above copyright
19   *   notice, this list of conditions and the following disclaimer.
20   *
21   * - Redistributions in binary form must reproduce the above
22   *   copyright notice, this list of conditions and the following
23   *   disclaimer in the documentation and/or other materials provided
24   *   with the distribution.
25   *
26   * - Neither the name of the Eclipse Foundation, Inc. nor the
27   *   names of its contributors may be used to endorse or promote
28   *   products derived from this software without specific prior
29   *   written permission.
30   *
31   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
32   * CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
33   * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
34   * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
35   * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
36   * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
37   * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
38   * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
39   * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
40   * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
41   * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
42   * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
43   * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
44   */
45  
46  package org.eclipse.jgit.lib;
47  
48  import java.io.FileNotFoundException;
49  import java.io.IOException;
50  import java.text.MessageFormat;
51  
52  import org.eclipse.jgit.errors.ConfigInvalidException;
53  import org.eclipse.jgit.errors.IncorrectObjectTypeException;
54  import org.eclipse.jgit.errors.MissingObjectException;
55  import org.eclipse.jgit.internal.JGitText;
56  import org.eclipse.jgit.revwalk.RevCommit;
57  import org.eclipse.jgit.revwalk.RevTree;
58  import org.eclipse.jgit.revwalk.RevWalk;
59  import org.eclipse.jgit.treewalk.TreeWalk;
60  import org.eclipse.jgit.util.RawParseUtils;
61  
62  /**
63   * Configuration file based on the blobs stored in the repository.
64   *
65   * This implementation currently only provides reading support, and is primarily
66   * useful for supporting the {@code .gitmodules} file.
67   */
68  public class BlobBasedConfig extends Config {
69  	/**
70  	 * Parse a configuration from a byte array.
71  	 *
72  	 * @param base
73  	 *            the base configuration file
74  	 * @param blob
75  	 *            the byte array, should be UTF-8 encoded text.
76  	 * @throws org.eclipse.jgit.errors.ConfigInvalidException
77  	 *             the byte array is not a valid configuration format.
78  	 */
79  	public BlobBasedConfig(Config base, final byte[] blob)
80  			throws ConfigInvalidException {
81  		super(base);
82  		final String decoded;
83  		if (isUtf8(blob)) {
84  			decoded = RawParseUtils.decode(RawParseUtils.UTF8_CHARSET,
85  					blob, 3, blob.length);
86  		} else {
87  			decoded = RawParseUtils.decode(blob);
88  		}
89  		fromText(decoded);
90  	}
91  
92  	/**
93  	 * Load a configuration file from a blob.
94  	 *
95  	 * @param base
96  	 *            the base configuration file
97  	 * @param db
98  	 *            the repository
99  	 * @param objectId
100 	 *            the object identifier
101 	 * @throws java.io.IOException
102 	 *             the blob cannot be read from the repository.
103 	 * @throws org.eclipse.jgit.errors.ConfigInvalidException
104 	 *             the blob is not a valid configuration format.
105 	 */
106 	public BlobBasedConfig(Config base, Repository db, AnyObjectId objectId)
107 			throws IOException, ConfigInvalidException {
108 		this(base, read(db, objectId));
109 	}
110 
111 	private static byte[] read(Repository db, AnyObjectId blobId)
112 			throws MissingObjectException, IncorrectObjectTypeException,
113 			IOException {
114 		try (ObjectReader or = db.newObjectReader()) {
115 			return read(or, blobId);
116 		}
117 	}
118 
119 	private static byte[] read(ObjectReader or, AnyObjectId blobId)
120 			throws MissingObjectException, IncorrectObjectTypeException,
121 			IOException {
122 		ObjectLoader loader = or.open(blobId, Constants.OBJ_BLOB);
123 		return loader.getCachedBytes(Integer.MAX_VALUE);
124 	}
125 
126 	/**
127 	 * Load a configuration file from a blob stored in a specific commit.
128 	 *
129 	 * @param base
130 	 *            the base configuration file
131 	 * @param db
132 	 *            the repository containing the objects.
133 	 * @param treeish
134 	 *            the tree (or commit) that contains the object
135 	 * @param path
136 	 *            the path within the tree
137 	 * @throws java.io.FileNotFoundException
138 	 *             the path does not exist in the commit's tree.
139 	 * @throws java.io.IOException
140 	 *             the tree and/or blob cannot be accessed.
141 	 * @throws org.eclipse.jgit.errors.ConfigInvalidException
142 	 *             the blob is not a valid configuration format.
143 	 */
144 	public BlobBasedConfig(Config base, Repository db, AnyObjectId treeish,
145 			String path) throws FileNotFoundException, IOException,
146 			ConfigInvalidException {
147 		this(base, read(db, treeish, path));
148 	}
149 
150 	private static byte[] read(Repository db, AnyObjectId treeish, String path)
151 			throws MissingObjectException, IncorrectObjectTypeException,
152 			IOException {
153 		try (ObjectReader or = db.newObjectReader()) {
154 			TreeWalk tree = TreeWalk.forPath(or, path, asTree(or, treeish));
155 			if (tree == null)
156 				throw new FileNotFoundException(MessageFormat.format(JGitText
157 						.get().entryNotFoundByPath, path));
158 			return read(or, tree.getObjectId(0));
159 		}
160 	}
161 
162 	private static AnyObjectId asTree(ObjectReader or, AnyObjectId treeish)
163 			throws MissingObjectException, IncorrectObjectTypeException,
164 			IOException {
165 		if (treeish instanceof RevTree)
166 			return treeish;
167 
168 		if (treeish instanceof RevCommit
169 				&& ((RevCommit) treeish).getTree() != null)
170 			return ((RevCommit) treeish).getTree();
171 
172 		try (RevWalk rw = new RevWalk(or)) {
173 			return rw.parseTree(treeish).getId();
174 		}
175 	}
176 }