/*

 * Copyright (c) 1997, 2019, 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

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 */

package java.util.jar;

import java.util.zip.*;

import java.io.*;

import sun.security.util.ManifestEntryVerifier;

import jdk.internal.util.jar.JarIndex;

/**

 * The {@code JarInputStream} class is used to read the contents of

 * a JAR file from any input stream. It extends the class

 * {@code java.util.zip.ZipInputStream} with support for reading

 * an optional {@code Manifest} entry. The {@code Manifest}

 * can be used to store meta-information about the JAR file and its entries.

 *

 * @author  David Connelly

 * @see     Manifest

 * @see     java.util.zip.ZipInputStream

 * @since   1.2

 */

public

class JarInputStream extends ZipInputStream {

    private Manifest man;

    private JarEntry first;

    private JarVerifier jv;

    private ManifestEntryVerifier mev;

    private final boolean doVerify;

    private boolean tryManifest;

    /**

     * Creates a new {@code JarInputStream} and reads the optional

     * manifest. If a manifest is present, also attempts to verify

     * the signatures if the JarInputStream is signed.

     * @param in the actual input stream

     * @throws    IOException if an I/O error has occurred

     */

    public JarInputStream(InputStream in) throws IOException {

        this(in, true);

    }

    /**

     * Creates a new {@code JarInputStream} and reads the optional

     * manifest. If a manifest is present and verify is true, also attempts

     * to verify the signatures if the JarInputStream is signed.

     *

     * @param in the actual input stream

     * @param verify whether or not to verify the JarInputStream if

     * it is signed.

     * @throws    IOException if an I/O error has occurred

     */

    public JarInputStream(InputStream in, boolean verify) throws IOException {

        super(in);

        this.doVerify = verify;

        // This implementation assumes the META-INF/MANIFEST.MF entry

        // should be either the first or the second entry (when preceded

        // by the dir META-INF/). It skips the META-INF/ and then

        // "consumes" the MANIFEST.MF to initialize the Manifest object.

        JarEntry e = (JarEntry)super.getNextEntry();

        if (e != null && e.getName().equalsIgnoreCase("META-INF/"))

            e = (JarEntry)super.getNextEntry();

        first = checkManifest(e);

    }

    private JarEntry checkManifest(JarEntry e)

        throws IOException

    {

        if (e != null && JarFile.MANIFEST_NAME.equalsIgnoreCase(e.getName())) {

            man = new Manifest();

            byte bytes[] = getBytes(new BufferedInputStream(this));

            man.read(new ByteArrayInputStream(bytes));

            closeEntry();

            if (doVerify) {

                jv = new JarVerifier(bytes);

                mev = new ManifestEntryVerifier(man);

            }

            return (JarEntry)super.getNextEntry();

        }

        return e;

    }

    private byte[] getBytes(InputStream is)

        throws IOException

    {

        byte[] buffer = new byte[8192];

        ByteArrayOutputStream baos = new ByteArrayOutputStream(2048);

        int n;

        while ((n = is.read(buffer, 0, buffer.length)) != -1) {

            baos.write(buffer, 0, n);

        }

        return baos.toByteArray();

    }

    /**

     * Returns the {@code Manifest} for this JAR file, or

     * {@code null} if none.

     *

     * @return the {@code Manifest} for this JAR file, or

     *         {@code null} if none.

     */

    public Manifest getManifest() {

        return man;

    }

    /**

     * Reads the next ZIP file entry and positions the stream at the

     * beginning of the entry data. If verification has been enabled,

     * any invalid signature detected while positioning the stream for

     * the next entry will result in an exception.

     * @throws    ZipException if a ZIP file error has occurred

     * @throws    IOException if an I/O error has occurred

     * @throws    SecurityException if any of the jar file entries

     *         are incorrectly signed.

     */

    public ZipEntry getNextEntry() throws IOException {

        JarEntry e;

        if (first == null) {

            e = (JarEntry)super.getNextEntry();

            if (tryManifest) {

                e = checkManifest(e);

                tryManifest = false;

            }

        } else {

            e = first;

            if (first.getName().equalsIgnoreCase(JarIndex.INDEX_NAME))

                tryManifest = true;

            first = null;

        }

        if (jv != null && e != null) {

            // At this point, we might have parsed all the meta-inf

            // entries and have nothing to verify. If we have

            // nothing to verify, get rid of the JarVerifier object.

            if (jv.nothingToVerify() == true) {

                jv = null;

                mev = null;

            } else {

                jv.beginEntry(e, mev);

            }

        }

        return e;

    }

    /**

     * Reads the next JAR file entry and positions the stream at the

     * beginning of the entry data. If verification has been enabled,

     * any invalid signature detected while positioning the stream for

     * the next entry will result in an exception.

     * @return the next JAR file entry, or null if there are no more entries

     * @throws    ZipException if a ZIP file error has occurred

     * @throws    IOException if an I/O error has occurred

     * @throws    SecurityException if any of the jar file entries

     *         are incorrectly signed.

     */

    public JarEntry getNextJarEntry() throws IOException {

        return (JarEntry)getNextEntry();

    }

    /**

     * Reads from the current JAR file entry into an array of bytes.

     * If {@code len} is not zero, the method

     * blocks until some input is available; otherwise, no

     * bytes are read and {@code 0} is returned.

     * If verification has been enabled, any invalid signature

     * on the current entry will be reported at some point before the

     * end of the entry is reached.

     * @param b the buffer into which the data is read

     * @param off the start offset in the destination array {@code b}

     * @param len the maximum number of bytes to read

     * @return the actual number of bytes read, or -1 if the end of the

     *         entry is reached

     * @throws     NullPointerException If {@code b} is {@code null}.

     * @throws     IndexOutOfBoundsException If {@code off} is negative,

     * {@code len} is negative, or {@code len} is greater than

     * {@code b.length - off}

     * @throws    ZipException if a ZIP file error has occurred

     * @throws    IOException if an I/O error has occurred

     * @throws    SecurityException if any of the jar file entries

     *         are incorrectly signed.

     */

    public int read(byte[] b, int off, int len) throws IOException {

        int n;

        if (first == null) {

            n = super.read(b, off, len);

        } else {

            n = -1;

        }

        if (jv != null) {

            jv.update(n, b, off, len, mev);

        }

        return n;

    }

    /**

     * Creates a new {@code JarEntry} ({@code ZipEntry}) for the

     * specified JAR file entry name. The manifest attributes of

     * the specified JAR file entry name will be copied to the new

     * <CODE>JarEntry</CODE>.

     *

     * @param name the name of the JAR/ZIP file entry

     * @return the {@code JarEntry} object just created

     */

    protected ZipEntry createZipEntry(String name) {

        JarEntry e = new JarEntry(name);

        if (man != null) {

            e.attr = man.getAttributes(name);

        }

        return e;

    }

}