commons-vfs2/src/main/java/org/apache/commons/vfs2/provider/jar/JarFileObject.java

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.apache.commons.vfs2.provider.jar;

import java.io.IOException;
import java.security.cert.Certificate;
import java.util.HashMap;
import java.util.Map;
import java.util.jar.Attributes;
import java.util.jar.JarEntry;
import java.util.jar.JarFile;
import java.util.jar.Manifest;
import java.util.zip.ZipEntry;

import org.apache.commons.vfs2.FileSystemException;
import org.apache.commons.vfs2.provider.AbstractFileName;
import org.apache.commons.vfs2.provider.zip.ZipFileObject;

/**
 * A file in a Jar file system.
 */
public class JarFileObject extends ZipFileObject {

    private final JarFileSystem fs;

    private Attributes attributes;

    protected JarFileObject(final AbstractFileName name, final ZipEntry entry, final JarFileSystem fs,
        final boolean zipExists) throws FileSystemException {
        super(name, entry, fs, zipExists);
        if (entry != null) {
            // For Java 9 and up: Force the certificates to be read and cached now. This avoids an
            // IllegalStateException in java.util.jar.JarFile.isMultiRelease() when it tries
            // to read the certificates and the file is closed.
            ((JarEntry) entry).getCertificates();
        }
        this.fs = fs;

        try {
            getAttributes(); // early get the attributes as the zip file might be closed
        } catch (final IOException e) {
            throw new FileSystemException(e);
        }
    }

    /**
     * Adds the source attributes to the destination map.
     */
    private void addAll(final Attributes src, final Map<String, Object> dest) {
        src.forEach((k, v) -> dest.put(String.valueOf(k), v));
    }

    /**
     * Returns the value of an attribute.
     */
    @Override
    protected Map<String, Object> doGetAttributes() throws Exception {
        final Map<String, Object> attrs = new HashMap<>();

        // Add the file system's attributes first
        final JarFileSystem fs = (JarFileSystem) getFileSystem();
        addAll(fs.getAttributes(), attrs);

        // Add this file's attributes
        addAll(getAttributes(), attrs);

        return attrs;
    }

    /**
     * Return the certificates of this JarEntry.
     */
    @Override
    protected Certificate[] doGetCertificates() {
        if (entry == null) {
            return null;
        }

        return ((JarEntry) entry).getCertificates();
    }

    /**
     * Returns the attributes of this file.
     */
    Attributes getAttributes() throws IOException {
        if (attributes == null) {
            if (entry == null) {
                attributes = new Attributes(1);
            } else {
                attributes = ((JarEntry) entry).getAttributes();
                if (attributes == null) {
                    attributes = new Attributes(1);
                }
            }
        }

        return attributes;
    }

    /**
     * Returns the Jar manifest.
     */
    Manifest getManifest() throws IOException {
        if (fs.getZipFile() == null) {
            return null;
        }

        return ((JarFile) fs.getZipFile()).getManifest();
    }
}