001/* JarInputStream.java - InputStream for reading jar files
002   Copyright (C) 2000, 2004 Free Software Foundation, Inc.
003
004This file is part of GNU Classpath.
005
006GNU Classpath is free software; you can redistribute it and/or modify
007it under the terms of the GNU General Public License as published by
008the Free Software Foundation; either version 2, or (at your option)
009any later version.
010
011GNU Classpath is distributed in the hope that it will be useful, but
012WITHOUT ANY WARRANTY; without even the implied warranty of
013MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
014General Public License for more details.
015
016You should have received a copy of the GNU General Public License
017along with GNU Classpath; see the file COPYING.  If not, write to the
018Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
01902110-1301 USA.
020
021Linking this library statically or dynamically with other modules is
022making a combined work based on this library.  Thus, the terms and
023conditions of the GNU General Public License cover the whole
024combination.
025
026As a special exception, the copyright holders of this library give you
027permission to link this library with independent modules to produce an
028executable, regardless of the license terms of these independent
029modules, and to copy and distribute the resulting executable under
030terms of your choice, provided that you also meet, for each linked
031independent module, the terms and conditions of the license of that
032module.  An independent module is a module which is not derived from
033or based on this library.  If you modify this library, you may extend
034this exception to your version of the library, but you are not
035obligated to do so.  If you do not wish to do so, delete this
036exception statement from your version. */
037
038package java.util.jar;
039
040import java.io.IOException;
041import java.io.InputStream;
042import java.util.zip.ZipEntry;
043import java.util.zip.ZipInputStream;
044
045/**
046 * InputStream for reading jar files.
047 * XXX - verification of the signatures in the Manifest file is not yet
048 * implemented.
049 *
050 * @since 1.2
051 * @author Mark Wielaard (mark@klomp.org)
052 */
053
054public class JarInputStream extends ZipInputStream
055{
056  // Fields
057
058  /** The manifest for this file or null when there was no manifest. */
059  private Manifest manifest;
060
061  /** The first real JarEntry for this file. Used by readManifest() to store
062     an entry that isn't the manifest but that should be returned by
063     getNextEntry next time it is called. Null when no firstEntry was read
064     while searching for the manifest entry, or when it has already been
065     returned by getNextEntry(). */
066  private JarEntry firstEntry;
067
068  // Constructors
069
070  /**
071   * Creates a new JarInputStream and tries to read the manifest.
072   * If such a manifest is present the JarInputStream tries to verify all
073   * the entry signatures while reading.
074   *
075   * @param in InputStream to read the jar from
076   * @exception IOException when an error occurs when opening or reading
077   */
078  public JarInputStream(InputStream in) throws IOException
079  {
080    this(in, true);
081  }
082
083  /**
084   * Creates a new JarInputStream and tries to read the manifest.
085   * If such a manifest is present and verify is true, the JarInputStream
086   * tries to verify all the entry signatures while reading.
087   *
088   * @param in InputStream to read the jar from
089   * @param verify whether or not to verify the manifest entries
090   * @exception IOException when an error occurs when opening or reading
091   */
092  public JarInputStream(InputStream in, boolean verify) throws IOException
093  {
094    super(in);
095    readManifest(verify);
096  }
097
098  // Methods
099
100  /**
101   * Set the manifest if found. Skips all entries that start with "META-INF/"
102   *
103   * @param verify when true (and a Manifest is found) checks the Manifest,
104   * when false no check is performed
105   * @exception IOException if an error occurs while reading
106   */
107  private void readManifest(boolean verify) throws IOException
108  {
109    firstEntry = (JarEntry) super.getNextEntry();
110    while ((firstEntry != null) &&
111           firstEntry.getName().startsWith("META-INF/"))
112      {
113        if (firstEntry.getName().equals(JarFile.MANIFEST_NAME))
114          {
115            manifest = new Manifest(this);
116          }
117        firstEntry = (JarEntry) super.getNextEntry();
118      }
119
120    if (verify)
121      {
122        // XXX
123      }
124  }
125
126  /**
127   * Creates a JarEntry for a particular name and consults the manifest
128   * for the Attributes of the entry.
129   * Used by <code>ZipEntry.getNextEntry()</code>
130   *
131   * @param name the name of the new entry
132   */
133  protected ZipEntry createZipEntry(String name)
134  {
135    ZipEntry zipEntry = super.createZipEntry(name);
136    JarEntry jarEntry = new JarEntry(zipEntry);
137    if (manifest != null)
138      {
139        jarEntry.attr = manifest.getAttributes(name);
140      }
141    return jarEntry;
142  }
143
144  /**
145   * Returns the Manifest for the jar file or null if there was no Manifest.
146   */
147  public Manifest getManifest()
148  {
149    return manifest;
150  }
151
152  /**
153   * Returns the next entry or null when there are no more entries.
154   * Does actually return a JarEntry, if you don't want to cast it yourself
155   * use <code>getNextJarEntry()</code>. Does not return any entries found
156   * at the beginning of the ZipFile that are special
157   * (those that start with "META-INF/").
158   *
159   * @exception IOException if an IO error occurs when reading the entry
160   */
161  public ZipEntry getNextEntry() throws IOException
162  {
163    ZipEntry entry;
164    if (firstEntry != null)
165      {
166        entry = firstEntry;
167        firstEntry = null;
168      }
169    else
170      {
171        entry = super.getNextEntry();
172      }
173    return entry;
174  }
175
176  /**
177   * Returns the next jar entry or null when there are no more entries.
178   *
179   * @exception IOException if an IO error occurs when reading the entry
180   */
181  public JarEntry getNextJarEntry() throws IOException
182  {
183    return (JarEntry) getNextEntry();
184  }
185
186  /**
187   * XXX
188   *
189   * @param buf XXX
190   * @param off XXX
191   * @param len XXX
192   * @return XXX
193   * @exception IOException XXX
194   */
195  public int read(byte[]buf, int off, int len) throws IOException
196  {
197    // XXX if (verify) {}
198    return super.read(buf, off, len);
199  }
200}