jardiff.java

编写程序

/*
 * @(#)JarDiff.java	1.13 03/06/26
 * 
 * Copyright 2004 Sun Microsystems, Inc. All rights reserved.
 * SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 */
package jnlp.sample.jardiff;

import java.io.*;
import java.util.*;
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 1.13, 06/26/03
 */
public class JarDiff implements JarDiffConstants {
    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 = null;

    // The JARDiff.java is the stand-along jardiff.jar tool. Thus, we do not
    // depend on Globals.java and other stuff here. Instead, we use an explicit
    // _debug flag.
    private static boolean _debug;

    public static ResourceBundle getResources() {
	if (_resources == null) {
	    _resources = ResourceBundle.getBundle("jnlp/sample/jardiff/resources/strings");
	}
	return _resources;
    }

    /**
     * Creates a patch from the two passed in files, writing the result
     * to <code>os</code>.
     */
    public static void createPatch(String oldPath, String newPath,
                            OutputStream os, boolean minimal) throws IOException{
        JarFile2 oldJar = new JarFile2(oldPath);
        JarFile2 newJar = new JarFile2(newPath);
      
        Iterator entries;
        HashMap moved = new HashMap();
        HashSet visited = new HashSet();
	HashSet implicit = new HashSet();
	HashSet moveSrc = new HashSet();
	HashSet newEntries = new HashSet();

	// FIRST PASS
	// Go through the entries in new jar and
	// determine which files are candidates for implicit moves
	// ( files that has the same filename and same content in old.jar
	// and new.jar )
	// and for files that cannot be implicitly moved, we will either
	// find out whether it is moved or new (modified)
	entries = newJar.getJarEntries();
	if (entries != null) {
	    while (entries.hasNext()) {
		JarEntry newEntry = (JarEntry)entries.next(); 
		String newname = newEntry.getName();
	
		// Return best match of contents, will return a name match if possible 
		String oldname = oldJar.getBestMatch(newJar, newEntry);
		if (oldname == null) {
		    // New or modified entry
		    if (_debug) {
			 System.out.println("NEW: "+ newname); 
		    }
		    newEntries.add(newname);
		} else {
		    // Content already exist - need to do a move
		    
		    // Should do implicit move? Yes, if names are the same, and
		    // no move command already exist from oldJar
		    if (oldname.equals(newname) && !moveSrc.contains(oldname)) {
			if (_debug) { 
			     System.out.println(newname + " added to implicit set!");
			}
			implicit.add(newname);
		    } else {
			// The 1.0.1/1.0 JarDiffPatcher cannot handle
			// multiple MOVE command with same src.
			// The work around here is if we are going to generate
			// a MOVE command with duplicate src, we will
			// instead add the target as a new file.  This way
			// the jardiff can be applied by 1.0.1/1.0
			// JarDiffPatcher also.
			if (!minimal && (implicit.contains(oldname) || 
					  moveSrc.contains(oldname) )) {
			    
			    // generate non-minimal jardiff
			    // for backward compatibility
			   
			    if (_debug) {
				    
				System.out.println("NEW: "+ newname); 
			    }
			    newEntries.add(newname);			
			} else {
			    // Use newname as key, since they are unique
			    if (_debug) {
				System.err.println("moved.put " + newname + " " + oldname); 
			    }
			    moved.put(newname, oldname);
			    moveSrc.add(oldname);
			}
			// Check if this disables an implicit 'move <oldname> <oldname>'
			if (implicit.contains(oldname) && minimal) { 
			  
			    if (_debug) {
				System.err.println("implicit.remove " + oldname);
				
				System.err.println("moved.put " + oldname + " " + oldname); 
				
			    }
			    implicit.remove(oldname);
			    moved.put(oldname, oldname);
			    moveSrc.add(oldname);		     
			}

		
		    } 
		}
	    }
	}

	
	// SECOND PASS: <deleted files> = <oldjarnames> - <implicitmoves> - 
	// <source of move commands> - <new or modified entries>
	ArrayList deleted = new ArrayList();
	entries = oldJar.getJarEntries();
	if (entries != null) {
            while (entries.hasNext()) {
		JarEntry oldEntry = (JarEntry)entries.next();
		String oldName = oldEntry.getName();
		if (!implicit.contains(oldName) && !moveSrc.contains(oldName)
		    && !newEntries.contains(oldName)) {
		    if (_debug) {
			System.err.println("deleted.add " + oldName);
		    }
		    deleted.add(oldName);
		}
	    }
	}
	
	//DEBUG
	if (_debug) {
	    //DEBUG:  print out moved map
	    entries = moved.keySet().iterator();
	    if (entries != null) {
		System.out.println("MOVED MAP!!!");
		while (entries.hasNext()) {
		    String newName = (String)entries.next();
		    String oldName = (String)moved.get(newName);	
		    System.out.println("key is " + newName + " value is " + oldName);
		}
	    }
	    
	    //DEBUG:  print out IMOVE map
	    entries = implicit.iterator();
	    if (entries != null) {
		System.out.println("IMOVE MAP!!!");
		while (entries.hasNext()) {
		    String newName = (String)entries.next();		 
		    System.out.println("key is " + newName);
		}
	    }
	}

	JarOutputStream jos = new JarOutputStream(os);

	// Write out all the MOVEs and REMOVEs
        createIndex(jos, deleted, moved);

        // Put in New and Modified entries
	entries = newEntries.iterator();
	if (entries != null) {
	   
	    while (entries.hasNext()) {
		String newName = (String)entries.next();		      
		if (_debug) {
		    System.out.println("New File: " + newName);
		}
		writeEntry(jos, newJar.getEntryByName(newName), newJar);
	    }
	}
     
    
        jos.finish();
    }

    /**
     * Writes the index file out to <code>jos</code>.
     * <code>oldEntries</code> gives the names of the files that were removed,
     * <code>movedMap</code> maps from the new name to the old name.
     */
    private static void createIndex(JarOutputStream jos, List oldEntries,
                             Map movedMap) throws
                       IOException {
        StringWriter writer = new StringWriter();

        writer.write(VERSION_HEADER);
        writer.write("\r\n");

        // Write out entries that have been removed
        for (int counter = 0; counter < oldEntries.size(); counter++) {
            String name = (String)oldEntries.get(counter);

            writer.write(REMOVE_COMMAND);
            writer.write(" ");
            writeEscapedString(writer, name);
            writer.write("\r\n");
        }

        // And those that have moved
        Iterator names = movedMap.keySet().iterator();

        if (names != null) {
            while (names.hasNext()) {
                String newName = (String)names.next();
                String oldName = (String)movedMap.get(newName);

		writer.write(MOVE_COMMAND);
		writer.write(" ");
		writeEscapedString(writer, oldName);
		writer.write(" ");
		writeEscapedString(writer, newName);
		writer.write("\r\n");
		   
            }
        }

        JarEntry je = new JarEntry(INDEX_NAME);
        byte[] bytes = writer.toString().getBytes("UTF-8");

        writer.close();
        jos.putNextEntry(je);
        jos.write(bytes, 0, bytes.length);
    }

    private static void writeEscapedString(Writer writer, String string)
                      throws IOException {
        int index = 0;
        int last = 0;
        char[] chars = null;

        while ((index = string.indexOf(' ', index)) != -1) {
            if (last != index) {
                if (chars == null) {
                    chars = string.toCharArray();
                }
                writer.write(chars, last, index - last);
            }
            last = index;
            index++;
            writer.write('\\');
        }
        if (last != 0) {
            writer.write(chars, last, chars.length - last);
        }
        else {
            // no spaces
            writer.write(string);
        }
    }

    private static void writeEntry(JarOutputStream jos, JarEntry entry,
                            JarFile2 file) throws IOException {
        writeEntry(jos, entry, file.getJarFile().getInputStream(entry));
    }

    private static void writeEntry(JarOutputStream jos, JarEntry entry,
                            InputStream data) throws IOException {
        jos.putNextEntry(entry);