Java 1.2 How-To/JavaHowTo.iso/3rdParty/jbuilder/unsupported/JDK1.2beta3/SOURCE/SRC.ZIP/java/util/jar/JarInputStream.java

Java Source | 1998-03-20 | 5.2 KB | 183 lines

/*
 * @(#)JarInputStream.java    1.15 98/03/18
 *
 * Copyright 1997, 1998 by Sun Microsystems, Inc.,
 * 901 San Antonio Road, Palo Alto, California, 94303, U.S.A.
 * All rights reserved.
 *
 * This software is the confidential and proprietary information
 * of Sun Microsystems, Inc. ("Confidential Information").  You
 * shall not disclose such Confidential Information and shall use
 * it only in accordance with the terms of the license agreement
 * you entered into with Sun.
 */

package java.util.jar;

import java.util.zip.*;
import java.io.*;
import java.security.Identity;

/**
 * The <code>JarInputStream</code> class is used to read the contents of
 * a JAR file from any input stream. It extends the class
 * <code>java.util.zip.ZipInputStream</code> with support for reading
 * an optional <code>Manifest</code> entry. The <code>Manifest</code>
 * can be used to store meta-information about the JAR file and its entries.
 *
 * @author  David Connelly
 * @version 1.15, 03/18/98
 * @see        Manifest
 * @see        java.util.zip.ZipInputStream
 * @since   JDK1.2
 */
public
class JarInputStream extends ZipInputStream {
    private Manifest man;
    private JarEntry manEntry;
    private JarEntry first;
    private JarVerifier jv;

    /**
     * Creates a new <code>JarInputStream</code> 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
     * @exception IOException if an I/O error has occurred
     */
    public JarInputStream(InputStream in) throws IOException {
    this(in, true);
    }

    /**
     * Creates a new <code>JarInputStream</code> 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.
     * @exception IOException if an I/O error has occurred
     */
    public JarInputStream(InputStream in, boolean verify) throws IOException {
    super(in);
    JarEntry e = (JarEntry)super.getNextEntry();

    if (e.getName().equalsIgnoreCase("META-INF/"))
        e = (JarEntry)super.getNextEntry();

    if (JarFile.MANIFEST_NAME.equalsIgnoreCase(e.getName())) {
        man = new Manifest();
        byte bytes[] = getBytes(new BufferedInputStream(this));
        man.read(new ByteArrayInputStream(bytes));
         //man.read(new BufferedInputStream(this));
        closeEntry();
        manEntry = e;
        if (verify) {
        jv = new JarVerifier(man, bytes);
        }
        first = getNextJarEntry();
    } else {
        first = e;
    }
    }

    private byte[] getBytes(InputStream is)
    throws IOException
    {
    byte[] buffer = new byte[8192];
    ByteArrayOutputStream baos = new ByteArrayOutputStream(2048);

    int n;

    baos.reset();
    while ((n = is.read(buffer, 0, buffer.length)) != -1) {
        baos.write(buffer, 0, n);
    }
    return baos.toByteArray();
    }

    /**
     * Returns the <code>Manifest</code> for this JAR file, or
     * <code>null</code> if none.
     */
    public Manifest getManifest() {
    return man;
    }

    /**
     * Returns the JarEntry for the manifest, or <code>null</code> if none.
     */
    public JarEntry getManifestEntry() {
    return manEntry;
    }

    /**
     * Reads the next ZIP file entry and positions stream at the beginning
     * of the entry data.
     * @exception ZipException if a ZIP file error has occurred
     * @exception IOException if an I/O error has occurred
     */
    public ZipEntry getNextEntry() throws IOException {
    JarEntry e;
    if (first == null) {
        e = (JarEntry)super.getNextEntry();
    } else {
        e = first;
        first = null;
    }
    if (jv != null && e != null) {
        jv.beginEntry(e);
    }
    return e;
    }

    /**
     * Reads the next JAR file entry and positions the stream at the
     * beginning of the entry data.
     * @exception ZipException if a ZIP file error has occurred
     * @exception IOException if an I/O error has occurred
     */
    public JarEntry getNextJarEntry() throws IOException {
    return (JarEntry)getNextEntry();
    }

    /**
     * Reads from the current JAR file entry into an array of bytes.
     * Blocks until some input is available.
     * @param b the buffer into which the data is read
     * @param off the start offset of the data
     * @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
     * @exception ZipException if a ZIP file error has occurred
     * @exception IOException if an I/O error has occurred
     */
    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);
    }
    return n;
    }

    /**
     * Creates a new <code>JarEntry</code> (<code>ZipEntry</code>) for the
     * specified JAR file entry name.
     *
     * @param name the name of the JAR/ZIP file entry
     */
    protected ZipEntry createZipEntry(String name) {
    JarEntry e = new JarEntry(name);
    if (man != null) {
        e.attr = man.getAttributes(name);
    }
    return e;
    }
}