src/jdk.zipfs/share/classes/jdk/nio/zipfs/JarFileSystem.java
changeset 47216 71c04702a3d5
parent 44257 3220d2ac3cee
child 48327 d2a837cf9ff1
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/jdk.zipfs/share/classes/jdk/nio/zipfs/JarFileSystem.java	Tue Sep 12 19:03:39 2017 +0200
@@ -0,0 +1,184 @@
+/*
+ * Copyright (c) 2015, 2017, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.  Oracle designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Oracle in the LICENSE file that accompanied this code.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+package jdk.nio.zipfs;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.lang.Runtime.Version;
+import java.nio.file.NoSuchFileException;
+import java.nio.file.Path;
+import java.util.Arrays;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.TreeMap;
+import java.util.function.Consumer;
+import java.util.function.Function;
+import java.util.jar.Attributes;
+import java.util.jar.Manifest;
+
+/**
+ * Adds aliasing to ZipFileSystem to support multi-release jar files.  An alias map
+ * is created by {@link JarFileSystem#createVersionedLinks(int)}.  The map is then
+ * consulted when an entry is looked up in {@link JarFileSystem#getEntry(byte[])}
+ * to determine if the entry has a corresponding versioned entry.  If so, the
+ * versioned entry is returned.
+ *
+ * @author Steve Drach
+ */
+
+class JarFileSystem extends ZipFileSystem {
+    private Function<byte[],byte[]> lookup;
+
+    @Override
+    IndexNode getInode(byte[] path) {
+        // check for an alias to a versioned entry
+        byte[] versionedPath = lookup.apply(path);
+        return versionedPath == null ? super.getInode(path) : super.getInode(versionedPath);
+    }
+
+    JarFileSystem(ZipFileSystemProvider provider, Path zfpath, Map<String,?> env)
+            throws IOException {
+        super(provider, zfpath, env);
+        lookup = path -> path;  // lookup needs to be set before isMultiReleaseJar is called
+                                // because it eventually calls getEntry
+        if (isMultiReleaseJar()) {
+            int version;
+            Object o = env.get("multi-release");
+            if (o instanceof String) {
+                String s = (String)o;
+                if (s.equals("runtime")) {
+                    version = Runtime.version().major();
+                } else {
+                    version = Integer.parseInt(s);
+                }
+            } else if (o instanceof Integer) {
+                version = (Integer)o;
+            } else if (o instanceof Version) {
+                version = ((Version)o).major();
+            } else {
+                throw new IllegalArgumentException("env parameter must be String, Integer, "
+                        + "or Version");
+            }
+            lookup = createVersionedLinks(version < 0 ? 0 : version);
+            setReadOnly();
+        }
+    }
+
+    private boolean isMultiReleaseJar() throws IOException {
+        try (InputStream is = newInputStream(getBytes("/META-INF/MANIFEST.MF"))) {
+            String multiRelease = new Manifest(is).getMainAttributes()
+                    .getValue(Attributes.Name.MULTI_RELEASE);
+            return "true".equalsIgnoreCase(multiRelease);
+        } catch (NoSuchFileException x) {
+            return false;
+        }
+    }
+
+    /**
+     * create a map of aliases for versioned entries, for example:
+     *   version/PackagePrivate.class -> META-INF/versions/9/version/PackagePrivate.class
+     *   version/PackagePrivate.java -> META-INF/versions/9/version/PackagePrivate.java
+     *   version/Version.class -> META-INF/versions/10/version/Version.class
+     *   version/Version.java -> META-INF/versions/10/version/Version.java
+     *
+     * then wrap the map in a function that getEntry can use to override root
+     * entry lookup for entries that have corresponding versioned entries
+     */
+    private Function<byte[],byte[]> createVersionedLinks(int version) {
+        HashMap<IndexNode,byte[]> aliasMap = new HashMap<>();
+        getVersionMap(version, getInode(getBytes("/META-INF/versions"))).values()
+                .forEach(versionNode -> {   // for each META-INF/versions/{n} directory
+                    // put all the leaf inodes, i.e. entries, into the alias map
+                    // possibly shadowing lower versioned entries
+                    walk(versionNode, entryNode -> {
+                        byte[] rootName = getRootName(versionNode, entryNode);
+                        if (rootName != null) {
+                            IndexNode rootNode = getInode(rootName);
+                            if (rootNode == null) { // no matching root node, make a virtual one
+                                rootNode = IndexNode.keyOf(rootName);
+                            }
+                            aliasMap.put(rootNode, entryNode.name);
+                        }
+                    });
+                });
+        return path -> aliasMap.get(IndexNode.keyOf(path));
+    }
+
+    /**
+     * create a sorted version map of version -> inode, for inodes <= max version
+     *   9 -> META-INF/versions/9
+     *  10 -> META-INF/versions/10
+     */
+    private TreeMap<Integer, IndexNode> getVersionMap(int version, IndexNode metaInfVersions) {
+        TreeMap<Integer,IndexNode> map = new TreeMap<>();
+        IndexNode child = metaInfVersions.child;
+        while (child != null) {
+            Integer key = getVersion(child.name, metaInfVersions.name.length + 1);
+            if (key != null && key <= version) {
+                map.put(key, child);
+            }
+            child = child.sibling;
+        }
+        return map;
+    }
+
+    /**
+     * extract the integer version number -- META-INF/versions/9 returns 9
+     */
+    private Integer getVersion(byte[] name, int offset) {
+        try {
+            return Integer.parseInt(getString(Arrays.copyOfRange(name, offset, name.length)));
+        } catch (NumberFormatException x) {
+            // ignore this even though it might indicate issues with the JAR structure
+            return null;
+        }
+    }
+
+    /**
+     * walk the IndexNode tree processing all leaf nodes
+     */
+    private void walk(IndexNode inode, Consumer<IndexNode> process) {
+        if (inode == null) return;
+        if (inode.isDir()) {
+            walk(inode.child, process);
+        } else {
+            process.accept(inode);
+        }
+        walk(inode.sibling, process);
+    }
+
+    /**
+     * extract the root name from a versioned entry name
+     *   given inode for META-INF/versions/9/foo/bar.class
+     *   and prefix META-INF/versions/9/
+     *   returns foo/bar.class
+     */
+    private byte[] getRootName(IndexNode prefix, IndexNode inode) {
+        int offset = prefix.name.length;
+        byte[] fullName = inode.name;
+        return Arrays.copyOfRange(fullName, offset, fullName.length);
+    }
+}