1 /*
2 * Copyright (c) 2015, 2016, 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
26 package jdk.nio.zipfs;
27
28 import java.io.IOException;
29 import java.io.InputStream;
30 import java.lang.Runtime.Version;
31 import java.nio.file.Path;
32 import java.util.Arrays;
33 import java.util.HashMap;
34 import java.util.Map;
35 import java.util.TreeMap;
36 import java.util.function.Consumer;
37 import java.util.function.Function;
38 import jdk.internal.util.jar.JarAttributes;
39
40 /**
41 * Adds aliasing to ZipFileSystem to support multi-release jar files. An alias map
42 * is created by {@link JarFileSystem#createVersionedLinks(int)}. The map is then
43 * consulted when an entry is looked up in {@link JarFileSystem#getEntry(byte[])}
44 * to determine if the entry has a corresponding versioned entry. If so, the
45 * versioned entry is returned.
46 *
47 * @author Steve Drach
48 */
49
50 class JarFileSystem extends ZipFileSystem {
51 private Function<byte[],byte[]> lookup;
52
53 @Override
54 IndexNode getInode(byte[] path) {
55 // check for an alias to a versioned entry
56 byte[] versionedPath = lookup.apply(path);
57 return versionedPath == null ? super.getInode(path) : super.getInode(versionedPath);
58 }
59
60 JarFileSystem(ZipFileSystemProvider provider, Path zfpath, Map<String,?> env)
61 throws IOException {
62 super(provider, zfpath, env);
63 lookup = path -> path; // lookup needs to be set before isMultiReleaseJar is called
64 // because it eventually calls getEntry
65 if (isMultiReleaseJar()) {
66 int version;
67 Object o = env.get("multi-release");
68 if (o instanceof String) {
69 String s = (String)o;
70 if (s.equals("runtime")) {
71 version = Runtime.version().major();
72 } else {
73 version = Integer.parseInt(s);
74 }
75 } else if (o instanceof Integer) {
76 version = (Integer)o;
77 } else if (o instanceof Version) {
78 version = ((Version)o).major();
79 } else {
80 throw new IllegalArgumentException("env parameter must be String, Integer, "
81 + "or Version");
82 }
83 lookup = createVersionedLinks(version < 0 ? 0 : version);
84 setReadOnly();
85 }
86 }
87
88 private boolean isMultiReleaseJar() {
89 try (InputStream is = newInputStream(getBytes("/META-INF/MANIFEST.MF"))) {
90 byte[] manifest = is.readAllBytes();
91 return JarAttributes.isMultiRelease(manifest);
92 } catch (IOException x) {
93 return false;
94 }
95 }
96
97 /**
98 * create a map of aliases for versioned entries, for example:
99 * version/PackagePrivate.class -> META-INF/versions/9/version/PackagePrivate.class
100 * version/PackagePrivate.java -> META-INF/versions/9/version/PackagePrivate.java
101 * version/Version.class -> META-INF/versions/10/version/Version.class
102 * version/Version.java -> META-INF/versions/10/version/Version.java
103 *
104 * then wrap the map in a function that getEntry can use to override root
105 * entry lookup for entries that have corresponding versioned entries
106 */
107 private Function<byte[],byte[]> createVersionedLinks(int version) {
108 HashMap<IndexNode,byte[]> aliasMap = new HashMap<>();
109 getVersionMap(version, getInode(getBytes("/META-INF/versions"))).values()
110 .forEach(versionNode -> { // for each META-INF/versions/{n} directory
111 // put all the leaf inodes, i.e. entries, into the alias map
112 // possibly shadowing lower versioned entries
113 walk(versionNode, entryNode -> {
114 byte[] rootName = getRootName(versionNode, entryNode);
115 if (rootName != null) {
116 IndexNode rootNode = getInode(rootName);
117 if (rootNode == null) { // no matching root node, make a virtual one
118 rootNode = IndexNode.keyOf(rootName);
119 }
120 aliasMap.put(rootNode, entryNode.name);
121 }
122 });
123 });
124 return path -> aliasMap.get(IndexNode.keyOf(path));
125 }
126
127 /**
128 * create a sorted version map of version -> inode, for inodes <= max version
129 * 9 -> META-INF/versions/9
130 * 10 -> META-INF/versions/10
131 */
132 private TreeMap<Integer, IndexNode> getVersionMap(int version, IndexNode metaInfVersions) {
133 TreeMap<Integer,IndexNode> map = new TreeMap<>();
134 IndexNode child = metaInfVersions.child;
135 while (child != null) {
136 Integer key = getVersion(child.name, metaInfVersions.name.length + 1);
137 if (key != null && key <= version) {
138 map.put(key, child);
139 }
140 child = child.sibling;
141 }
142 return map;
143 }
144
145 /**
146 * extract the integer version number -- META-INF/versions/9 returns 9
147 */
148 private Integer getVersion(byte[] name, int offset) {
149 try {
150 return Integer.parseInt(getString(Arrays.copyOfRange(name, offset, name.length)));
151 } catch (NumberFormatException x) {
152 // ignore this even though it might indicate issues with the JAR structure
153 return null;
154 }
155 }
156
157 /**
158 * walk the IndexNode tree processing all leaf nodes
159 */
160 private void walk(IndexNode inode, Consumer<IndexNode> process) {
161 if (inode == null) return;
162 if (inode.isDir()) {
163 walk(inode.child, process);
164 } else {
165 process.accept(inode);
166 }
167 walk(inode.sibling, process);
168 }
169
170 /**
171 * extract the root name from a versioned entry name
172 * given inode for META-INF/versions/9/foo/bar.class
173 * and prefix META-INF/versions/9/
174 * returns foo/bar.class
175 */
176 private byte[] getRootName(IndexNode prefix, IndexNode inode) {
177 int offset = prefix.name.length;
178 byte[] fullName = inode.name;
179 return Arrays.copyOfRange(fullName, offset, fullName.length);
180 }
181 }