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package jnlp.sample.jardiff;

import java.io.*;
import java.util.*;
import java.net.URL;
import java.util.jar.*;
import java.util.zip.*;

/**
 * JarDiff is able to create a jar file containing the delta between two
 * jar files (old and new). The delta jar file can then be applied to the
 * old jar file to reconstruct the new jar file.
 * <p>
 * Refer to the JNLP spec for details on how this is done.
 *
 * @version 1.11, 06/26/03
 */
public class JarDiffPatcher implements JarDiffConstants, Patcher {
    private static final int DEFAULT_READ_SIZE = 2048;
    private static byte[] newBytes = new byte[DEFAULT_READ_SIZE];
    private static byte[] oldBytes = new byte[DEFAULT_READ_SIZE];
    private static ResourceBundle _resources = JarDiff.getResources();

    public static ResourceBundle getResources() {
        return JarDiff.getResources();
    }

    public void applyPatch(Patcher.PatchDelegate delegate, String oldJarPath,
                           String jarDiffPath, OutputStream result) throws IOException {
            File oldFile = new File(oldJarPath);
            File diffFile = new File(jarDiffPath);
            JarOutputStream jos = new JarOutputStream(result);
            JarFile oldJar = new JarFile(oldFile);
            JarFile jarDiff = new JarFile(diffFile);
            Set ignoreSet = new HashSet();
            Map renameMap = new HashMap();


            determineNameMapping(jarDiff, ignoreSet, renameMap);

            // get all keys in renameMap
            Object[] keys = renameMap.keySet().toArray();


            // Files to implicit move
            Set oldjarNames  = new HashSet();

            Enumeration oldEntries = oldJar.entries();
            if (oldEntries != null) {
                while  (oldEntries.hasMoreElements()) {
                    oldjarNames.add(((JarEntry)oldEntries.nextElement()).getName());
                }
            }

            // size depends on the three parameters below, which is
            // basically the counter for each loop that do the actual
            // writes to the output file
            // since oldjarNames.size() changes in the first two loop
            // below, we need to adjust the size accordingly also when
            // oldjarNames.size() changes
            double size = oldjarNames.size() + keys.length + jarDiff.size();
            double currentEntry = 0;

            // Handle all remove commands
            oldjarNames.removeAll(ignoreSet);
            size -= ignoreSet.size();


            // Add content from JARDiff
            Enumeration entries = jarDiff.entries();
            if (entries != null) {
                while (entries.hasMoreElements()) {
                    JarEntry entry = (JarEntry)entries.nextElement();



                    if (!INDEX_NAME.equals(entry.getName())) {

                        updateDelegate(delegate, currentEntry, size);
                        currentEntry++;

                        writeEntry(jos, entry, jarDiff);

                        // Remove entry from oldjarNames since no implicit
                        //move is needed
                        boolean wasInOld = oldjarNames.remove(entry.getName());

                        // Update progress counters. If it was in old, we do
                        // not need an implicit move, so adjust total size.
                        if (wasInOld) size--;

                    }
                    else {
                        // no write is done, decrement size
                        size--;
                    }
                }
            }



            // go through the renameMap and apply move for each entry
            for (int j = 0; j < keys.length; j++) {



                // Apply move <oldName> <newName> command
                String newName = (String)keys[j];
                String oldName = (String)renameMap.get(newName);

                // Get source JarEntry
                JarEntry oldEntry = oldJar.getJarEntry(oldName);

                if (oldEntry == null) {
                    String moveCmd = MOVE_COMMAND + oldName + " " + newName;
                    handleException("jardiff.error.badmove", moveCmd);
                }

                // Create dest JarEntry
                JarEntry newEntry = new JarEntry(newName);
                newEntry.setTime(oldEntry.getTime());
                newEntry.setSize(oldEntry.getSize());
                newEntry.setCompressedSize(oldEntry.getCompressedSize());
                newEntry.setCrc(oldEntry.getCrc());
                newEntry.setMethod(oldEntry.getMethod());
                newEntry.setExtra(oldEntry.getExtra());
                newEntry.setComment(oldEntry.getComment());


                updateDelegate(delegate, currentEntry, size);
                currentEntry++;

                writeEntry(jos, newEntry, oldJar.getInputStream(oldEntry));

                // Remove entry from oldjarNames since no implicit
                //move is needed
                boolean wasInOld = oldjarNames.remove(oldName);

                // Update progress counters. If it was in old, we do
                // not need an implicit move, so adjust total size.
                if (wasInOld) size--;

            }

            // implicit move
            Iterator iEntries = oldjarNames.iterator();
            if (iEntries != null) {
                while (iEntries.hasNext()) {

                    String name = (String)iEntries.next();
                    JarEntry entry = oldJar.getJarEntry(name);

                    updateDelegate(delegate, currentEntry, size);
                    currentEntry++;

                    writeEntry(jos, entry, oldJar);
                }
            }

            updateDelegate(delegate, currentEntry, size);

            jos.finish();
    }

    private void updateDelegate(Patcher.PatchDelegate delegate, double currentSize, double size) {
        if (delegate != null) {
            delegate.patching((int)(currentSize/size));
        }
    }

    private void determineNameMapping(JarFile jarDiff, Set ignoreSet,
                                      Map renameMap) throws IOException {
        InputStream is = jarDiff.getInputStream(jarDiff.getEntry(INDEX_NAME));

        if (is == null) {
            handleException("jardiff.error.noindex", null);

        }
        LineNumberReader indexReader = new LineNumberReader
            (new InputStreamReader(is, "UTF-8"));
        String line = indexReader.readLine();

        if (line == null || !line.equals(VERSION_HEADER)) {
            handleException("jardiff.error.badheader", line);

        }

        while ((line = indexReader.readLine()) != null) {
            if (line.startsWith(REMOVE_COMMAND)) {
                List sub = getSubpaths(line.substring(REMOVE_COMMAND.
                                                          length()));

                if (sub.size() != 1) {
                    handleException("jardiff.error.badremove", line);

                }
                ignoreSet.add(sub.get(0));
            }
            else if (line.startsWith(MOVE_COMMAND)) {
                List sub = getSubpaths(line.substring(MOVE_COMMAND.length()));

                if (sub.size() != 2) {
                    handleException("jardiff.error.badmove", line);

                }
                // target of move should be the key
                if (renameMap.put(sub.get(1), sub.get(0)) != null) {
                    // invalid move - should not move to same target twice
                    handleException("jardiff.error.badmove", line);
                }
            }
            else if (line.length() > 0) {
                handleException("jardiff.error.badcommand", line);

            }
        }
    }

    private void handleException(String errorMsg, String line) throws IOException {
        try {
            throw new IOException(getResources().getString(errorMsg) + " " + line);
        } catch (MissingResourceException mre) {
             System.err.println("Fatal error: " + errorMsg);
             new Throwable().printStackTrace(System.err);
             System.exit(-1);
        }
    }

    private List getSubpaths(String path) {
        int index = 0;
        int length = path.length();
        ArrayList sub = new ArrayList();

        while (index < length) {
            while (index < length && Character.isWhitespace
                       (path.charAt(index))) {
                index++;
            }
            if (index < length) {
                int start = index;
                int last = start;
                String subString = null;

                while (index < length) {
                    char aChar = path.charAt(index);
                    if (aChar == '\\' && (index + 1) < length &&
                        path.charAt(index + 1) == ' ') {

                        if (subString == null) {
                            subString = path.substring(last, index);
                        }
                        else {
                            subString += path.substring(last, index);
                        }
                        last = ++index;
                    }
                    else if (Character.isWhitespace(aChar)) {
                        break;
                    }
                    index++;
                }
                if (last != index) {
                    if (subString == null) {
                        subString = path.substring(last, index);
                    }
                    else {
                        subString += path.substring(last, index);
                    }
                }
                sub.add(subString);
            }
        }
        return sub;
    }

    private void writeEntry(JarOutputStream jos, JarEntry entry,
                            JarFile file) throws IOException {
        writeEntry(jos, entry, file.getInputStream(entry));
    }

    private void writeEntry(JarOutputStream jos, JarEntry entry,
                            InputStream data) throws IOException {
        //Create a new ZipEntry to clear the compressed size. 5079423
        jos.putNextEntry(new ZipEntry(entry.getName()));

        // Read the entry
        int size = data.read(newBytes);

        while (size != -1) {
            jos.write(newBytes, 0, size);
            size = data.read(newBytes);
        }
        data.close();
    }
}
