1 /*

     2  * Copyright (c) 2015, 2017, 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.NoSuchFileException;

    32 import java.nio.file.Path;

    33 import java.util.Arrays;

    34 import java.util.HashMap;

    35 import java.util.Map;

    36 import java.util.TreeMap;

    37 import java.util.function.Consumer;

    38 import java.util.function.Function;

    39 import java.util.jar.Attributes;

    40 import java.util.jar.Manifest;

    41 

    42 /**

    43  * Adds aliasing to ZipFileSystem to support multi-release jar files.  An alias map

    44  * is created by {@link JarFileSystem#createVersionedLinks(int)}.  The map is then

    45  * consulted when an entry is looked up in {@link JarFileSystem#getEntry(byte[])}

    46  * to determine if the entry has a corresponding versioned entry.  If so, the

    47  * versioned entry is returned.

    48  *

    49  * @author Steve Drach

    50  */

    51 

    52 class JarFileSystem extends ZipFileSystem {

    53     private Function<byte[],byte[]> lookup;

    54 

    55     @Override

    56     IndexNode getInode(byte[] path) {

    57         // check for an alias to a versioned entry

    58         byte[] versionedPath = lookup.apply(path);

    59         return versionedPath == null ? super.getInode(path) : super.getInode(versionedPath);

    60     }

    61 

    62     JarFileSystem(ZipFileSystemProvider provider, Path zfpath, Map<String,?> env)

    63             throws IOException {

    64         super(provider, zfpath, env);

    65         lookup = path -> path;  // lookup needs to be set before isMultiReleaseJar is called

    66                                 // because it eventually calls getEntry

    67         if (isMultiReleaseJar()) {

    68             int version;

    69             Object o = env.get("multi-release");

    70             if (o instanceof String) {

    71                 String s = (String)o;

    72                 if (s.equals("runtime")) {

    73                     version = Runtime.version().major();

    74                 } else {

    75                     version = Integer.parseInt(s);

    76                 }

    77             } else if (o instanceof Integer) {

    78                 version = (Integer)o;

    79             } else if (o instanceof Version) {

    80                 version = ((Version)o).major();

    81             } else {

    82                 throw new IllegalArgumentException("env parameter must be String, Integer, "

    83                         + "or Version");

    84             }

    85             lookup = createVersionedLinks(version < 0 ? 0 : version);

    86             setReadOnly();

    87         }

    88     }

    89 

    90     private boolean isMultiReleaseJar() throws IOException {

    91         try (InputStream is = newInputStream(getBytes("/META-INF/MANIFEST.MF"))) {

    92             String multiRelease = new Manifest(is).getMainAttributes()

    93                     .getValue(Attributes.Name.MULTI_RELEASE);

    94             return "true".equalsIgnoreCase(multiRelease);

    95         } catch (NoSuchFileException x) {

    96             return false;

    97         }

    98     }

    99 

   100     /**

   101      * create a map of aliases for versioned entries, for example:

   102      *   version/PackagePrivate.class -> META-INF/versions/9/version/PackagePrivate.class

   103      *   version/PackagePrivate.java -> META-INF/versions/9/version/PackagePrivate.java

   104      *   version/Version.class -> META-INF/versions/10/version/Version.class

   105      *   version/Version.java -> META-INF/versions/10/version/Version.java

   106      *

   107      * then wrap the map in a function that getEntry can use to override root

   108      * entry lookup for entries that have corresponding versioned entries

   109      */

   110     private Function<byte[],byte[]> createVersionedLinks(int version) {

   111         HashMap<IndexNode,byte[]> aliasMap = new HashMap<>();

   112         getVersionMap(version, getInode(getBytes("/META-INF/versions"))).values()

   113                 .forEach(versionNode -> {   // for each META-INF/versions/{n} directory

   114                     // put all the leaf inodes, i.e. entries, into the alias map

   115                     // possibly shadowing lower versioned entries

   116                     walk(versionNode, entryNode -> {

   117                         byte[] rootName = getRootName(versionNode, entryNode);

   118                         if (rootName != null) {

   119                             IndexNode rootNode = getInode(rootName);

   120                             if (rootNode == null) { // no matching root node, make a virtual one

   121                                 rootNode = IndexNode.keyOf(rootName);

   122                             }

   123                             aliasMap.put(rootNode, entryNode.name);

   124                         }

   125                     });

   126                 });

   127         return path -> aliasMap.get(IndexNode.keyOf(path));

   128     }

   129 

   130     /**

   131      * create a sorted version map of version -> inode, for inodes <= max version

   132      *   9 -> META-INF/versions/9

   133      *  10 -> META-INF/versions/10

   134      */

   135     private TreeMap<Integer, IndexNode> getVersionMap(int version, IndexNode metaInfVersions) {

   136         TreeMap<Integer,IndexNode> map = new TreeMap<>();

   137         IndexNode child = metaInfVersions.child;

   138         while (child != null) {

   139             Integer key = getVersion(child.name, metaInfVersions.name.length + 1);

   140             if (key != null && key <= version) {

   141                 map.put(key, child);

   142             }

   143             child = child.sibling;

   144         }

   145         return map;

   146     }

   147 

   148     /**

   149      * extract the integer version number -- META-INF/versions/9 returns 9

   150      */

   151     private Integer getVersion(byte[] name, int offset) {

   152         try {

   153             return Integer.parseInt(getString(Arrays.copyOfRange(name, offset, name.length)));

   154         } catch (NumberFormatException x) {

   155             // ignore this even though it might indicate issues with the JAR structure

   156             return null;

   157         }

   158     }

   159 

   160     /**

   161      * walk the IndexNode tree processing all leaf nodes

   162      */

   163     private void walk(IndexNode inode, Consumer<IndexNode> process) {

   164         if (inode == null) return;

   165         if (inode.isDir()) {

   166             walk(inode.child, process);

   167         } else {

   168             process.accept(inode);

   169         }

   170         walk(inode.sibling, process);

   171     }

   172 

   173     /**

   174      * extract the root name from a versioned entry name

   175      *   given inode for META-INF/versions/9/foo/bar.class

   176      *   and prefix META-INF/versions/9/

   177      *   returns foo/bar.class

   178      */

   179     private byte[] getRootName(IndexNode prefix, IndexNode inode) {

   180         int offset = prefix.name.length;

   181         byte[] fullName = inode.name;

   182         return Arrays.copyOfRange(fullName, offset, fullName.length);

   183     }

   184 }