/*
 * Copyright (c) 1999, 2018 Oracle and/or its affiliates. All rights reserved.
 *
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Public License v. 2.0, which is available at
 * http://www.eclipse.org/legal/epl-2.0.
 *
 * This Source Code may also be made available under the following Secondary
 * Licenses when the conditions for such availability set forth in the
 * Eclipse Public License v. 2.0 are satisfied: GNU General Public License,
 * version 2 with the GNU Classpath Exception, which is available at
 * https://www.gnu.org/software/classpath/license.html.
 *
 * SPDX-License-Identifier: EPL-2.0 OR GPL-2.0 WITH Classpath-exception-2.0
 */

package com.sun.ts.lib.util.sec.misc;

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

/**
 * This class is used to maintain mappings from packages, classes and resources
 * to their enclosing JAR files. Mappings are kept at the package level except
 * for class or resource files that are located at the root directory.
 * URLClassLoader uses the mapping information to determine where to fetch an
 * extension class or resource from.
 *
 * @author Zhenghua Li
 * @since 1.3
 */

public class JarIndex {

  /**
   * The hash map that maintains mappings from package/classe/resource to jar
   * file list(s)
   */
  private HashMap indexMap;

  /**
   * The hash map that maintains mappings from jar file to
   * package/class/resource lists
   */
  private HashMap jarMap;

  /*
   * An ordered list of jar file names.
   */
  private String[] jarFiles;

  /**
   * The index file name.
   */
  public static final String INDEX_NAME = "META-INF/INDEX.LIST";

  /**
   * Constructs a new, empty jar index.
   */
  public JarIndex() {
    indexMap = new HashMap();
    jarMap = new HashMap();
  }

  /**
   * Constructs a new index from the specified input stream.
   *
   * @param is
   *          the input stream containing the index data
   */
  public JarIndex(InputStream is) throws IOException {
    this();
    read(is);
  }

  /**
   * Constructs a new index for the specified list of jar files.
   *
   * @param files
   *          the list of jar files to construct the index from.
   */
  public JarIndex(String[] files) throws IOException {
    this();
    this.jarFiles = files;
    parseJars(files);
  }

  /**
   * Returns the jar index, or <code>null</code> if none.
   *
   * @param jar
   *          the JAR file to get the index from.
   * @exception IOException
   *              if an I/O error has occurred.
   */
  public static JarIndex getJarIndex(JarFile jar, MetaIndex metaIndex)
      throws IOException {
    JarIndex index = null;
    /*
     * If metaIndex is not null, check the meta index to see if
     * META-INF/INDEX.LIST is contained in jar file or not.
     */
    if (metaIndex != null && !metaIndex.mayContain(INDEX_NAME)) {
      return null;
    }
    JarEntry e = jar.getJarEntry(INDEX_NAME);
    // if found, then load the index
    if (e != null) {
      index = new JarIndex(jar.getInputStream(e));
    }
    return index;
  }

  /**
   * Returns the jar files that are defined in this index.
   */
  public String[] getJarFiles() {
    return jarFiles;
  }

  /*
   * Add the key, value pair to the hashmap, the value will be put in a linked
   * list which is created if necessary.
   */
  private void addToList(String key, String value, HashMap t) {
    LinkedList list = (LinkedList) t.get(key);
    if (list == null) {
      list = new LinkedList();
      list.add(value);
      t.put(key, list);
    } else if (!list.contains(value)) {
      list.add(value);
    }
  }

  /**
   * Returns the list of jar files that are mapped to the file.
   *
   * @param fileName
   *          the key of the mapping
   */
  public LinkedList get(String fileName) {
    LinkedList jarFiles = null;
    if ((jarFiles = (LinkedList) indexMap.get(fileName)) == null) {
      /* try the package name again */
      int pos;
      if ((pos = fileName.lastIndexOf("/")) != -1) {
        jarFiles = (LinkedList) indexMap.get(fileName.substring(0, pos));
      }
    }
    return jarFiles;
  }

  /**
   * Add the mapping from the specified file to the specified jar file. If there
   * were no mapping for the package of the specified file before, a new linked
   * list will be created, the jar file is added to the list and a new mapping
   * from the package to the jar file list is added to the hashmap. Otherwise,
   * the jar file will be added to the end of the existing list.
   *
   * @param fileName
   *          the file name
   * @param jarName
   *          the jar file that the file is mapped to
   *
   */
  public void add(String fileName, String jarName) {
    String packageName;
    int pos;
    if ((pos = fileName.lastIndexOf("/")) != -1) {
      packageName = fileName.substring(0, pos);
    } else {
      packageName = fileName;
    }

    // add the mapping to indexMap
    addToList(packageName, jarName, indexMap);

    // add the mapping to jarMap
    addToList(jarName, packageName, jarMap);
  }

  /**
   * Go through all the jar files and construct the index table.
   */
  private void parseJars(String[] files) throws IOException {
    if (files == null) {
      return;
    }

    String currentJar = null;

    for (int i = 0; i < files.length; i++) {
      currentJar = files[i];
      ZipFile zrf = new ZipFile(currentJar.replace('/', File.separatorChar));

      Enumeration entries = zrf.entries();
      while (entries.hasMoreElements()) {
        String fileName = ((ZipEntry) (entries.nextElement())).getName();
        // Index the META-INF directory, but not the index or manifest.
        if (!fileName.startsWith("META-INF/")
            || !(fileName.equals("META-INF/") || fileName.equals(INDEX_NAME)
                || fileName.equals(JarFile.MANIFEST_NAME))) {
          add(fileName, currentJar);
        }
      }
      zrf.close();
    }
  }

  /**
   * Writes the index to the specified OutputStream
   *
   * @param out
   *          the output stream
   * @exception IOException
   *              if an I/O error has occurred
   */
  public void write(OutputStream out) throws IOException {
    BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(out, "UTF8"));
    bw.write("JarIndex-Version: 1.0\n\n");

    if (jarFiles != null) {
      for (int i = 0; i < jarFiles.length; i++) {
        /* print out the jar file name */
        String jar = jarFiles[i];
        bw.write(jar + "\n");
        LinkedList jarlist = (LinkedList) jarMap.get(jar);
        if (jarlist != null) {
          Iterator listitr = jarlist.iterator();
          while (listitr.hasNext()) {
            bw.write((String) (listitr.next()) + "\n");
          }
        }
        bw.write("\n");
      }
      bw.flush();
    }
  }

  /**
   * Reads the index from the specified InputStream.
   *
   * @param is
   *          the input stream
   * @exception IOException
   *              if an I/O error has occurred
   */
  public void read(InputStream is) throws IOException {
    BufferedReader br = new BufferedReader(new InputStreamReader(is, "UTF8"));
    String line = null;
    String currentJar = null;

    /* an ordered list of jar file names */
    Vector jars = new Vector();

    /* read until we see a .jar line */
    while ((line = br.readLine()) != null && !line.endsWith(".jar"))
      ;

    for (; line != null; line = br.readLine()) {
      if (line.length() == 0)
        continue;

      if (line.endsWith(".jar")) {
        currentJar = line;
        jars.add(currentJar);
      } else {
        String name = line;
        addToList(name, currentJar, indexMap);
        addToList(currentJar, name, jarMap);
      }
    }

    jarFiles = (String[]) jars.toArray(new String[jars.size()]);
  }

  /**
   * Merges the current index into another index, taking into account the
   * relative path of the current index.
   *
   * @param toIndex
   *          The destination index which the current index will merge into.
   * @param path
   *          The relative path of the this index to the destination index.
   *
   */
  public void merge(JarIndex toIndex, String path) {
    Iterator itr = indexMap.entrySet().iterator();
    while (itr.hasNext()) {
      Map.Entry e = (Map.Entry) itr.next();
      String packageName = (String) e.getKey();
      LinkedList from_list = (LinkedList) e.getValue();
      Iterator listItr = from_list.iterator();
      while (listItr.hasNext()) {
        String jarName = (String) listItr.next();
        if (path != null) {
          jarName = path.concat(jarName);
        }
        toIndex.add(packageName, jarName);
      }
    }
  }
}
