/*

 * Copyright (c) 1997, 2013, 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 java.util.jar;

import java.io.FilterInputStream;

import java.io.DataOutputStream;

import java.io.InputStream;

import java.io.OutputStream;

import java.io.IOException;

import java.util.Map;

import java.util.HashMap;

import java.util.Iterator;

/**

 * The Manifest class is used to maintain Manifest entry names and their

 * associated Attributes. There are main Manifest Attributes as well as

 * per-entry Attributes. For information on the Manifest format, please

 * see the

 * <a href="../../../../technotes/guides/jar/jar.html">

 * Manifest format specification</a>.

 *

 * @author  David Connelly

 * @see     Attributes

 * @since   1.2

 */

public class Manifest implements Cloneable {

    // manifest main attributes

    private Attributes attr = new Attributes();

    // manifest entries

    private Map<String, Attributes> entries = new HashMap<>();

    /**

     * Constructs a new, empty Manifest.

     */

    public Manifest() {

    }

    /**

     * Constructs a new Manifest from the specified input stream.

     *

     * @param is the input stream containing manifest data

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

     */

    public Manifest(InputStream is) throws IOException {

        read(is);

    }

    /**

     * Constructs a new Manifest that is a copy of the specified Manifest.

     *

     * @param man the Manifest to copy

     */

    public Manifest(Manifest man) {

        attr.putAll(man.getMainAttributes());

        entries.putAll(man.getEntries());

    }

    /**

     * Returns the main Attributes for the Manifest.

     * @return the main Attributes for the Manifest

     */

    public Attributes getMainAttributes() {

        return attr;

    }

    /**

     * Returns a Map of the entries contained in this Manifest. Each entry

     * is represented by a String name (key) and associated Attributes (value).

     * The Map permits the {@code null} key, but no entry with a null key is

     * created by {@link #read}, nor is such an entry written by using {@link

     * #write}.

     *

     * @return a Map of the entries contained in this Manifest

     */

    public Map<String,Attributes> getEntries() {

        return entries;

    }

    /**

     * Returns the Attributes for the specified entry name.

     * This method is defined as:

     * <pre>

     *      return (Attributes)getEntries().get(name)

     * </pre>

     * Though {@code null} is a valid {@code name}, when

     * {@code getAttributes(null)} is invoked on a {@code Manifest}

     * obtained from a jar file, {@code null} will be returned.  While jar

     * files themselves do not allow {@code null}-named attributes, it is

     * possible to invoke {@link #getEntries} on a {@code Manifest}, and

     * on that result, invoke {@code put} with a null key and an

     * arbitrary value.  Subsequent invocations of

     * {@code getAttributes(null)} will return the just-{@code put}

     * value.

     * <p>

     * Note that this method does not return the manifest's main attributes;

     * see {@link #getMainAttributes}.

     *

     * @param name entry name

     * @return the Attributes for the specified entry name

     */

    public Attributes getAttributes(String name) {

        return getEntries().get(name);

    }

    /**

     * Clears the main Attributes as well as the entries in this Manifest.

     */

    public void clear() {

        attr.clear();

        entries.clear();

    }

    /**

     * Writes the Manifest to the specified OutputStream.

     * Attributes.Name.MANIFEST_VERSION must be set in

     * MainAttributes prior to invoking this method.

     *

     * @param out the output stream

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

     * @see #getMainAttributes

     */

    @SuppressWarnings("deprecation")

    public void write(OutputStream out) throws IOException {

        DataOutputStream dos = new DataOutputStream(out);

        // Write out the main attributes for the manifest

        attr.writeMain(dos);

        // Now write out the pre-entry attributes

        for (Map.Entry<String, Attributes> e : entries.entrySet()) {

            StringBuffer buffer = new StringBuffer("Name: ");

            String value = e.getKey();

            if (value != null) {

                byte[] vb = value.getBytes("UTF8");

                value = new String(vb, 0, 0, vb.length);

            }

            buffer.append(value);

            buffer.append("\r\n");

            make72Safe(buffer);

            dos.writeBytes(buffer.toString());

            e.getValue().write(dos);

        }

        dos.flush();

    }

    /**

     * Adds line breaks to enforce a maximum 72 bytes per line.

     */

    static void make72Safe(StringBuffer line) {

        int length = line.length();

        if (length > 72) {

            int index = 70;

            while (index < length - 2) {

                line.insert(index, "\r\n ");

                index += 72;

                length += 3;

            }

        }

        return;

    }

    /**

     * Reads the Manifest from the specified InputStream. The entry

     * names and attributes read will be merged in with the current

     * manifest entries.

     *

     * @param is the input stream

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

     */

    public void read(InputStream is) throws IOException {

        // Buffered input stream for reading manifest data

        FastInputStream fis = new FastInputStream(is);

        // Line buffer

        byte[] lbuf = new byte[512];

        // Read the main attributes for the manifest

        attr.read(fis, lbuf);

        // Total number of entries, attributes read

        int ecount = 0, acount = 0;

        // Average size of entry attributes

        int asize = 2;

        // Now parse the manifest entries

        int len;

        String name = null;

        boolean skipEmptyLines = true;

        byte[] lastline = null;

        while ((len = fis.readLine(lbuf)) != -1) {

            if (lbuf[--len] != '\n') {

                throw new IOException("manifest line too long");

            }

            if (len > 0 && lbuf[len-1] == '\r') {

                --len;

            }

            if (len == 0 && skipEmptyLines) {

                continue;

            }

            skipEmptyLines = false;

            if (name == null) {

                name = parseName(lbuf, len);

                if (name == null) {

                    throw new IOException("invalid manifest format");

                }

                if (fis.peek() == ' ') {

                    // name is wrapped

                    lastline = new byte[len - 6];

                    System.arraycopy(lbuf, 6, lastline, 0, len - 6);

                    continue;

                }

            } else {

                // continuation line

                byte[] buf = new byte[lastline.length + len - 1];

                System.arraycopy(lastline, 0, buf, 0, lastline.length);

                System.arraycopy(lbuf, 1, buf, lastline.length, len - 1);

                if (fis.peek() == ' ') {

                    // name is wrapped

                    lastline = buf;

                    continue;

                }

                name = new String(buf, 0, buf.length, "UTF8");

                lastline = null;

            }

            Attributes attr = getAttributes(name);

            if (attr == null) {

                attr = new Attributes(asize);

                entries.put(name, attr);

            }

            attr.read(fis, lbuf);

            ecount++;

            acount += attr.size();

            //XXX: Fix for when the average is 0. When it is 0,

            // you get an Attributes object with an initial

            // capacity of 0, which tickles a bug in HashMap.

            asize = Math.max(2, acount / ecount);

            name = null;

            skipEmptyLines = true;

        }

    }

    private String parseName(byte[] lbuf, int len) {

        if (toLower(lbuf[0]) == 'n' && toLower(lbuf[1]) == 'a' &&

            toLower(lbuf[2]) == 'm' && toLower(lbuf[3]) == 'e' &&

            lbuf[4] == ':' && lbuf[5] == ' ') {

            try {

                return new String(lbuf, 6, len - 6, "UTF8");

            }

            catch (Exception e) {

            }

        }

        return null;

    }

    private int toLower(int c) {

        return (c >= 'A' && c <= 'Z') ? 'a' + (c - 'A') : c;

    }

    /**

     * Returns true if the specified Object is also a Manifest and has

     * the same main Attributes and entries.

     *

     * @param o the object to be compared

     * @return true if the specified Object is also a Manifest and has

     * the same main Attributes and entries

     */

    public boolean equals(Object o) {

        if (o instanceof Manifest) {

            Manifest m = (Manifest)o;

            return attr.equals(m.getMainAttributes()) &&

                   entries.equals(m.getEntries());

        } else {

            return false;

        }

    }

    /**

     * Returns the hash code for this Manifest.

     */

    public int hashCode() {

        return attr.hashCode() + entries.hashCode();

    }

    /**

     * Returns a shallow copy of this Manifest.  The shallow copy is

     * implemented as follows:

     * <pre>

     *     public Object clone() { return new Manifest(this); }

     * </pre>

     * @return a shallow copy of this Manifest

     */

    public Object clone() {

        return new Manifest(this);

    }

    /*

     * A fast buffered input stream for parsing manifest files.

     */

    static class FastInputStream extends FilterInputStream {

        private byte buf[];

        private int count = 0;

        private int pos = 0;

        FastInputStream(InputStream in) {

            this(in, 8192);

        }

        FastInputStream(InputStream in, int size) {

            super(in);

            buf = new byte[size];

        }

        public int read() throws IOException {

            if (pos >= count) {

                fill();

                if (pos >= count) {

                    return -1;

                }

            }

            return Byte.toUnsignedInt(buf[pos++]);

        }

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

            int avail = count - pos;

            if (avail <= 0) {

                if (len >= buf.length) {

                    return in.read(b, off, len);

                }

                fill();

                avail = count - pos;

                if (avail <= 0) {

                    return -1;

                }

            }

            if (len > avail) {

                len = avail;

            }

            System.arraycopy(buf, pos, b, off, len);

            pos += len;

            return len;

        }

        /*

         * Reads 'len' bytes from the input stream, or until an end-of-line

         * is reached. Returns the number of bytes read.

         */

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

            byte[] tbuf = this.buf;

            int total = 0;

            while (total < len) {

                int avail = count - pos;

                if (avail <= 0) {

                    fill();

                    avail = count - pos;

                    if (avail <= 0) {

                        return -1;

                    }

                }

                int n = len - total;

                if (n > avail) {

                    n = avail;

                }

                int tpos = pos;

                int maxpos = tpos + n;

                while (tpos < maxpos && tbuf[tpos++] != '\n') ;

                n = tpos - pos;

                System.arraycopy(tbuf, pos, b, off, n);

                off += n;

                total += n;

                pos = tpos;

                if (tbuf[tpos-1] == '\n') {

                    break;

                }

            }

            return total;

        }

        public byte peek() throws IOException {

            if (pos == count)

                fill();

            if (pos == count)

                return -1; // nothing left in buffer

            return buf[pos];

        }

        public int readLine(byte[] b) throws IOException {

            return readLine(b, 0, b.length);

        }

        public long skip(long n) throws IOException {

            if (n <= 0) {

                return 0;

            }

            long avail = count - pos;

            if (avail <= 0) {

                return in.skip(n);

            }

            if (n > avail) {

                n = avail;

            }

            pos += n;

            return n;

        }

        public int available() throws IOException {

            return (count - pos) + in.available();

        }

        public void close() throws IOException {

            if (in != null) {

                in.close();

                in = null;

                buf = null;

            }

        }

        private void fill() throws IOException {

            count = pos = 0;

            int n = in.read(buf, 0, buf.length);

            if (n > 0) {

                count = n;

            }

        }

    }

}