package org.apache.maven.shared.jar.identification.hash;

 /*

  * Licensed to the Apache Software Foundation (ASF) under one

  * or more contributor license agreements.  See the NOTICE file

  * distributed with this work for additional information

  * regarding copyright ownership.  The ASF licenses this file

  * to you under the Apache License, Version 2.0 (the

  * "License"); you may not use this file except in compliance

  * with the License.  You may obtain a copy of the License at

  *

  *   http://www.apache.org/licenses/LICENSE-2.0

  *

  * Unless required by applicable law or agreed to in writing,

  * software distributed under the License is distributed on an

  * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY

  * KIND, either express or implied.  See the License for the

  * specific language governing permissions and limitations

  * under the License.

  */

 import org.apache.maven.shared.jar.JarAnalyzer;

 import org.apache.maven.shared.jar.JarData;

 import org.codehaus.plexus.digest.DigesterException;

 import org.codehaus.plexus.digest.StreamingDigester;

 import org.codehaus.plexus.logging.AbstractLogEnabled;

 import org.codehaus.plexus.util.IOUtil;

 import java.io.IOException;

 import java.io.InputStream;

 import java.util.Iterator;

 import java.util.jar.JarEntry;

 /**

  * Analyzer that calculates the hash code for the entire file. Can be used to detect an exact copy of the file's class

  * data. Useful to see thru a recompile, recompression, or timestamp change.

  * <p/>

  * If you are not using Plexus, you must call {@link #setDigester(org.codehaus.plexus.digest.StreamingDigester)} before use

  *

  * @plexus.component role="org.apache.maven.shared.jar.identification.hash.JarHashAnalyzer" role-hint="bytecode"

  */

 public class JarBytecodeHashAnalyzer

     extends AbstractLogEnabled

     implements JarHashAnalyzer

 {

     /**

      * The streaming digester to use for computing the hash. Under Plexus, the default is SHA-1.

      *

      * @plexus.requirement role-hint="sha1"

      */

     private StreamingDigester digester;

     public String computeHash( JarAnalyzer jarAnalyzer )

     {

         JarData jarData = jarAnalyzer.getJarData();

         String result = jarData.getBytecodeHash();

         if ( result == null )

         {

             Iterator it = jarAnalyzer.getClassEntries().iterator();

             try

             {

                 digester.reset();

                 while ( it.hasNext() )

                 {

                     JarEntry entry = (JarEntry) it.next();

                     computeEntryBytecodeHash( jarAnalyzer.getEntryInputStream( entry ) );

                 }

                 result = digester.calc();

                 jarData.setBytecodeHash( result );

             }

             catch ( DigesterException e )

             {

                 getLogger().warn( "Unable to calculate the hashcode.", e );

             }

             catch ( IOException e )

             {

                 getLogger().warn( "Unable to calculate the hashcode.", e );

             }

         }

         return result;

     }

     private void computeEntryBytecodeHash( InputStream is )

         throws IOException, DigesterException

     {

         try

         {

             digester.update( is );

         }

         finally

         {

             IOUtil.close( is );

         }

     }

     public void setDigester( StreamingDigester digester )

     {

         this.digester = digester;

     }

 }