/*
 * Copyright 1997-2009 Sun Microsystems, Inc.  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.  Sun designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
 * CA 95054 USA or visit www.sun.com if you need additional information or
 * have any questions.
 */

package java.util.jar;

import java.io.*;
import java.lang.ref.SoftReference;
import java.util.*;
import java.util.zip.*;
import java.security.CodeSigner;
import java.security.cert.Certificate;
import java.security.AccessController;
import sun.security.action.GetPropertyAction;
import sun.security.util.ManifestEntryVerifier;
import sun.misc.SharedSecrets;

/**
 * The <code>JarFile</code> class is used to read the contents of a jar file
 * from any file that can be opened with <code>java.io.RandomAccessFile</code>.
 * It extends the class <code>java.util.zip.ZipFile</code> with support
 * for reading an optional <code>Manifest</code> entry. The
 * <code>Manifest</code> can be used to specify meta-information about the
 * jar file and its entries.
 *
 * <p> Unless otherwise noted, passing a <tt>null</tt> argument to a constructor
 * or method in this class will cause a {@link NullPointerException} to be
 * thrown.
 *
 * @author  David Connelly
 * @see     Manifest
 * @see     java.util.zip.ZipFile
 * @see     java.util.jar.JarEntry
 * @since   1.2
 */
public
class JarFile extends ZipFile {
    private SoftReference<Manifest> manRef;
    private JarEntry manEntry;
    private JarVerifier jv;
    private boolean jvInitialized;
    private boolean verify;
    private boolean computedHasClassPathAttribute;
    private boolean hasClassPathAttribute;

    // Set up JavaUtilJarAccess in SharedSecrets
    static {
        SharedSecrets.setJavaUtilJarAccess(new JavaUtilJarAccessImpl());
    }

    /**
     * The JAR manifest file name.
     */
    public static final String MANIFEST_NAME = "META-INF/MANIFEST.MF";

    /**
     * Creates a new <code>JarFile</code> to read from the specified
     * file <code>name</code>. The <code>JarFile</code> will be verified if
     * it is signed.
     * @param name the name of the jar file to be opened for reading
     * @throws IOException if an I/O error has occurred
     * @throws SecurityException if access to the file is denied
     *         by the SecurityManager
     */
    public JarFile(String name) throws IOException {
        this(new File(name), true, ZipFile.OPEN_READ);
    }

    /**
     * Creates a new <code>JarFile</code> to read from the specified
     * file <code>name</code>.
     * @param name the name of the jar file to be opened for reading
     * @param verify whether or not to verify the jar file if
     * it is signed.
     * @throws IOException if an I/O error has occurred
     * @throws SecurityException if access to the file is denied
     *         by the SecurityManager
     */
    public JarFile(String name, boolean verify) throws IOException {
        this(new File(name), verify, ZipFile.OPEN_READ);
    }

    /**
     * Creates a new <code>JarFile</code> to read from the specified
     * <code>File</code> object. The <code>JarFile</code> will be verified if
     * it is signed.
     * @param file the jar file to be opened for reading
     * @throws IOException if an I/O error has occurred
     * @throws SecurityException if access to the file is denied
     *         by the SecurityManager
     */
    public JarFile(File file) throws IOException {
        this(file, true, ZipFile.OPEN_READ);
    }


    /**
     * Creates a new <code>JarFile</code> to read from the specified
     * <code>File</code> object.
     * @param file the jar file to be opened for reading
     * @param verify whether or not to verify the jar file if
     * it is signed.
     * @throws IOException if an I/O error has occurred
     * @throws SecurityException if access to the file is denied
     *         by the SecurityManager.
     */
    public JarFile(File file, boolean verify) throws IOException {
        this(file, verify, ZipFile.OPEN_READ);
    }


    /**
     * Creates a new <code>JarFile</code> to read from the specified
     * <code>File</code> object in the specified mode.  The mode argument
     * must be either <tt>OPEN_READ</tt> or <tt>OPEN_READ | OPEN_DELETE</tt>.
     *
     * @param file the jar file to be opened for reading
     * @param verify whether or not to verify the jar file if
     * it is signed.
     * @param mode the mode in which the file is to be opened
     * @throws IOException if an I/O error has occurred
     * @throws IllegalArgumentException
     *         if the <tt>mode</tt> argument is invalid
     * @throws SecurityException if access to the file is denied
     *         by the SecurityManager
     * @since 1.3
     */
    public JarFile(File file, boolean verify, int mode) throws IOException {
        super(file, mode);
        this.verify = verify;
    }

    /**
     * Returns the jar file manifest, or <code>null</code> if none.
     *
     * @return the jar file manifest, or <code>null</code> if none
     *
     * @throws IllegalStateException
     *         may be thrown if the jar file has been closed
     */
    public Manifest getManifest() throws IOException {
        return getManifestFromReference();
    }

    private Manifest getManifestFromReference() throws IOException {
        Manifest man = manRef != null ? manRef.get() : null;

        if (man == null) {

            JarEntry manEntry = getManEntry();

            // If found then load the manifest
            if (manEntry != null) {
                if (verify) {
                    byte[] b = getBytes(manEntry);
                    man = new Manifest(new ByteArrayInputStream(b));
                    if (!jvInitialized) {
                        jv = new JarVerifier(b);
                    }
                } else {
                    man = new Manifest(super.getInputStream(manEntry));
                }
                manRef = new SoftReference(man);
            }
        }
        return man;
    }

    private native String[] getMetaInfEntryNames();

    /**
     * Returns the <code>JarEntry</code> for the given entry name or
     * <code>null</code> if not found.
     *
     * @param name the jar file entry name
     * @return the <code>JarEntry</code> for the given entry name or
     *         <code>null</code> if not found.
     *
     * @throws IllegalStateException
     *         may be thrown if the jar file has been closed
     *
     * @see java.util.jar.JarEntry
     */
    public JarEntry getJarEntry(String name) {
        return (JarEntry)getEntry(name);
    }

    /**
     * Returns the <code>ZipEntry</code> for the given entry name or
     * <code>null</code> if not found.
     *
     * @param name the jar file entry name
     * @return the <code>ZipEntry</code> for the given entry name or
     *         <code>null</code> if not found
     *
     * @throws IllegalStateException
     *         may be thrown if the jar file has been closed
     *
     * @see java.util.zip.ZipEntry
     */
    public ZipEntry getEntry(String name) {
        ZipEntry ze = super.getEntry(name);
        if (ze != null) {
            return new JarFileEntry(ze);
        }
        return null;
    }

    /**
     * Returns an enumeration of the zip file entries.
     */
    public Enumeration<JarEntry> entries() {
        final Enumeration enum_ = super.entries();
        return new Enumeration<JarEntry>() {
            public boolean hasMoreElements() {
                return enum_.hasMoreElements();
            }
            public JarFileEntry nextElement() {
                ZipEntry ze = (ZipEntry)enum_.nextElement();
                return new JarFileEntry(ze);
            }
        };
    }

    private class JarFileEntry extends JarEntry {
        JarFileEntry(ZipEntry ze) {
            super(ze);
        }
        public Attributes getAttributes() throws IOException {
            Manifest man = JarFile.this.getManifest();
            if (man != null) {
                return man.getAttributes(getName());
            } else {
                return null;
            }
        }
        public Certificate[] getCertificates() {
            try {
                maybeInstantiateVerifier();
            } catch (IOException e) {
                throw new RuntimeException(e);
            }
            if (certs == null && jv != null) {
                certs = jv.getCerts(getName());
            }
            return certs == null ? null : certs.clone();
        }
        public CodeSigner[] getCodeSigners() {
            try {
                maybeInstantiateVerifier();
            } catch (IOException e) {
                throw new RuntimeException(e);
            }
            if (signers == null && jv != null) {
                signers = jv.getCodeSigners(getName());
            }
            return signers == null ? null : signers.clone();
        }
    }

    /*
     * Ensures that the JarVerifier has been created if one is
     * necessary (i.e., the jar appears to be signed.) This is done as
     * a quick check to avoid processing of the manifest for unsigned
     * jars.
     */
    private void maybeInstantiateVerifier() throws IOException {
        if (jv != null) {
            return;
        }

        if (verify) {
            String[] names = getMetaInfEntryNames();
            if (names != null) {
                for (int i = 0; i < names.length; i++) {
                    String name = names[i].toUpperCase(Locale.ENGLISH);
                    if (name.endsWith(".DSA") ||
                        name.endsWith(".RSA") ||
                        name.endsWith(".EC") ||
                        name.endsWith(".SF")) {
                        // Assume since we found a signature-related file
                        // that the jar is signed and that we therefore
                        // need a JarVerifier and Manifest
                        getManifest();
                        return;
                    }
                }
            }
            // No signature-related files; don't instantiate a
            // verifier
            verify = false;
        }
    }


    /*
     * Initializes the verifier object by reading all the manifest
     * entries and passing them to the verifier.
     */
    private void initializeVerifier() {
        ManifestEntryVerifier mev = null;

        // Verify "META-INF/" entries...
        try {
            String[] names = getMetaInfEntryNames();
            if (names != null) {
                for (int i = 0; i < names.length; i++) {
                    JarEntry e = getJarEntry(names[i]);
                    if (!e.isDirectory()) {
                        if (mev == null) {
                            mev = new ManifestEntryVerifier
                                (getManifestFromReference());
                        }
                        byte[] b = getBytes(e);
                        if (b != null && b.length > 0) {
                            jv.beginEntry(e, mev);
                            jv.update(b.length, b, 0, b.length, mev);
                            jv.update(-1, null, 0, 0, mev);
                        }
                    }
                }
            }
        } catch (IOException ex) {
            // if we had an error parsing any blocks, just
            // treat the jar file as being unsigned
            jv = null;
            verify = false;
        }

        // if after initializing the verifier we have nothing
        // signed, we null it out.

        if (jv != null) {

            jv.doneWithMeta();
            if (JarVerifier.debug != null) {
                JarVerifier.debug.println("done with meta!");
            }

            if (jv.nothingToVerify()) {
                if (JarVerifier.debug != null) {
                    JarVerifier.debug.println("nothing to verify!");
                }
                jv = null;
                verify = false;
            }
        }
    }

    /*
     * Reads all the bytes for a given entry. Used to process the
     * META-INF files.
     */
    private byte[] getBytes(ZipEntry ze) throws IOException {
        byte[] b = new byte[(int)ze.getSize()];
        DataInputStream is = new DataInputStream(super.getInputStream(ze));
        is.readFully(b, 0, b.length);
        is.close();
        return b;
    }

    /**
     * Returns an input stream for reading the contents of the specified
     * zip file entry.
     * @param ze the zip file entry
     * @return an input stream for reading the contents of the specified
     *         zip file entry
     * @throws ZipException if a zip file format error has occurred
     * @throws IOException if an I/O error has occurred
     * @throws SecurityException if any of the jar file entries
     *         are incorrectly signed.
     * @throws IllegalStateException
     *         may be thrown if the jar file has been closed
     */
    public synchronized InputStream getInputStream(ZipEntry ze)
        throws IOException
    {
        maybeInstantiateVerifier();
        if (jv == null) {
            return super.getInputStream(ze);
        }
        if (!jvInitialized) {
            initializeVerifier();
            jvInitialized = true;
            // could be set to null after a call to
            // initializeVerifier if we have nothing to
            // verify
            if (jv == null)
                return super.getInputStream(ze);
        }

        // wrap a verifier stream around the real stream
        return new JarVerifier.VerifierStream(
            getManifestFromReference(),
            ze instanceof JarFileEntry ?
            (JarEntry) ze : getJarEntry(ze.getName()),
            super.getInputStream(ze),
            jv);
    }

    // Statics for hand-coded Boyer-Moore search in hasClassPathAttribute()
    // The bad character shift for "class-path"
    private static int[] lastOcc;
    // The good suffix shift for "class-path"
    private static int[] optoSft;
    // Initialize the shift arrays to search for "class-path"
    private static char[] src = {'c','l','a','s','s','-','p','a','t','h'};
    static {
        lastOcc = new int[128];
        optoSft = new int[10];
        lastOcc[(int)'c']=1;
        lastOcc[(int)'l']=2;
        lastOcc[(int)'s']=5;
        lastOcc[(int)'-']=6;
        lastOcc[(int)'p']=7;
        lastOcc[(int)'a']=8;
        lastOcc[(int)'t']=9;
        lastOcc[(int)'h']=10;
        for (int i=0; i<9; i++)
            optoSft[i]=10;
        optoSft[9]=1;
    }

    private JarEntry getManEntry() {
        if (manEntry == null) {
            // First look up manifest entry using standard name
            manEntry = getJarEntry(MANIFEST_NAME);
            if (manEntry == null) {
                // If not found, then iterate through all the "META-INF/"
                // entries to find a match.
                String[] names = getMetaInfEntryNames();
                if (names != null) {
                    for (int i = 0; i < names.length; i++) {
                        if (MANIFEST_NAME.equals(
                                                 names[i].toUpperCase(Locale.ENGLISH))) {
                            manEntry = getJarEntry(names[i]);
                            break;
                        }
                    }
                }
            }
        }
        return manEntry;
    }

    // Returns true iff this jar file has a manifest with a class path
    // attribute. Returns false if there is no manifest or the manifest
    // does not contain a "Class-Path" attribute. Currently exported to
    // core libraries via sun.misc.SharedSecrets.
    boolean hasClassPathAttribute() throws IOException {
        if (computedHasClassPathAttribute) {
            return hasClassPathAttribute;
        }

        hasClassPathAttribute = false;
        if (!isKnownToNotHaveClassPathAttribute()) {
            JarEntry manEntry = getManEntry();
            if (manEntry != null) {
                byte[] b = new byte[(int)manEntry.getSize()];
                DataInputStream dis = new DataInputStream(
                                                          super.getInputStream(manEntry));
                dis.readFully(b, 0, b.length);
                dis.close();

                int last = b.length - src.length;
                int i = 0;
                next:
                while (i<=last) {
                    for (int j=9; j>=0; j--) {
                        char c = (char) b[i+j];
                        c = (((c-'A')|('Z'-c)) >= 0) ? (char)(c + 32) : c;
                        if (c != src[j]) {
                            i += Math.max(j + 1 - lastOcc[c&0x7F], optoSft[j]);
                            continue next;
                        }
                    }
                    hasClassPathAttribute = true;
                    break;
                }
            }
        }
        computedHasClassPathAttribute = true;
        return hasClassPathAttribute;
    }

    private static String javaHome;
    private static String[] jarNames;
    private boolean isKnownToNotHaveClassPathAttribute() {
        // Optimize away even scanning of manifest for jar files we
        // deliver which don't have a class-path attribute. If one of
        // these jars is changed to include such an attribute this code
        // must be changed.
        if (javaHome == null) {
            javaHome = AccessController.doPrivileged(
                new GetPropertyAction("java.home"));
        }
        if (jarNames == null) {
            String[] names = new String[10];
            String fileSep = File.separator;
            int i = 0;
            names[i++] = fileSep + "rt.jar";
            names[i++] = fileSep + "sunrsasign.jar";
            names[i++] = fileSep + "jsse.jar";
            names[i++] = fileSep + "jce.jar";
            names[i++] = fileSep + "charsets.jar";
            names[i++] = fileSep + "dnsns.jar";
            names[i++] = fileSep + "ldapsec.jar";
            names[i++] = fileSep + "localedata.jar";
            names[i++] = fileSep + "sunjce_provider.jar";
            names[i++] = fileSep + "sunpkcs11.jar";
            jarNames = names;
        }

        String name = getName();
        String localJavaHome = javaHome;
        if (name.startsWith(localJavaHome)) {
            String[] names = jarNames;
            for (int i = 0; i < names.length; i++) {
                if (name.endsWith(names[i])) {
                    return true;
                }
            }
        }
        return false;
    }
}