001    /* JarInputStream.java - InputStream for reading jar files
002       Copyright (C) 2000, 2004 Free Software Foundation, Inc.
003    
004    This file is part of GNU Classpath.
005    
006    GNU Classpath is free software; you can redistribute it and/or modify
007    it under the terms of the GNU General Public License as published by
008    the Free Software Foundation; either version 2, or (at your option)
009    any later version.
010    
011    GNU Classpath is distributed in the hope that it will be useful, but
012    WITHOUT ANY WARRANTY; without even the implied warranty of
013    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
014    General Public License for more details.
015    
016    You should have received a copy of the GNU General Public License
017    along with GNU Classpath; see the file COPYING.  If not, write to the
018    Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
019    02110-1301 USA.
020    
021    Linking this library statically or dynamically with other modules is
022    making a combined work based on this library.  Thus, the terms and
023    conditions of the GNU General Public License cover the whole
024    combination.
025    
026    As a special exception, the copyright holders of this library give you
027    permission to link this library with independent modules to produce an
028    executable, regardless of the license terms of these independent
029    modules, and to copy and distribute the resulting executable under
030    terms of your choice, provided that you also meet, for each linked
031    independent module, the terms and conditions of the license of that
032    module.  An independent module is a module which is not derived from
033    or based on this library.  If you modify this library, you may extend
034    this exception to your version of the library, but you are not
035    obligated to do so.  If you do not wish to do so, delete this
036    exception statement from your version. */
037    
038    package java.util.jar;
039    
040    import java.io.IOException;
041    import java.io.InputStream;
042    import java.util.zip.ZipEntry;
043    import 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    
054    public 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    }