package org.apache.maven.plugins.shade.resource;
   
   /*
    * 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 java.io.IOException;
  import java.io.InputStream;
  import java.util.Arrays;
  import java.util.List;
  import java.util.Map;
  import java.util.jar.Attributes;
  import java.util.jar.JarEntry;
  import java.util.jar.JarFile;
  import java.util.jar.JarOutputStream;
  import java.util.jar.Manifest;
  
  import org.apache.maven.plugins.shade.relocation.Relocator;
  
  /**
   * A resource processor that allows the arbitrary addition of attributes to
   * the first MANIFEST.MF that is found in the set of JARs being processed, or
   * to a newly created manifest for the shaded JAR.
   *
   * @author Jason van Zyl
   * @since 1.2
   */
  public class ManifestResourceTransformer
      implements ResourceTransformer
  {
      private final List<String> defaultAttributes = Arrays.asList( "Export-Package",
                                                                    "Import-Package",
                                                                    "Provide-Capability",
                                                                    "Require-Capability" ); 
      
      // Configuration
      private String mainClass;
  
      private Map<String, Object> manifestEntries;
  
      private List<String> additionalAttributes;
  
      // Fields
      private boolean manifestDiscovered;
  
      private Manifest manifest;
      
      public void setMainClass( String mainClass )
      {
          this.mainClass = mainClass;
      }
      
      public void setManifestEntries( Map<String, Object> manifestEntries )
      {
          this.manifestEntries = manifestEntries;
      }
      
      public void setAdditionalAttributes( List<String> additionalAttributes )
      {
          this.additionalAttributes = additionalAttributes;
      }
  
      @Override
      public boolean canTransformResource( String resource )
      {
          if ( JarFile.MANIFEST_NAME.equalsIgnoreCase( resource ) )
          {
              return true;
          }
  
          return false;
      }
  
      @Override
      public void processResource( String resource, InputStream is, List<Relocator> relocators )
          throws IOException
      {
          // We just want to take the first manifest we come across as that's our project's manifest. This is the behavior
          // now which is situational at best. Right now there is no context passed in with the processing so we cannot
          // tell what artifact is being processed.
          if ( !manifestDiscovered )
          {
              manifest = new Manifest( is );
  
             if ( relocators != null && !relocators.isEmpty() ) 
             {
                 final Attributes attributes = manifest.getMainAttributes();
 
                 for ( final String attribute : defaultAttributes )
                 {
                     final String attributeValue = attributes.getValue( attribute );
                     if ( attributeValue != null )
                     {
                         String newValue = relocate( attributeValue, relocators );
                         attributes.putValue( attribute, newValue );
                     }
                 }
 
                 if ( additionalAttributes != null )
                 {
                     for ( final String attribute : additionalAttributes )
                     {
                         final String attributeValue = attributes.getValue( attribute );
                         if ( attributeValue != null )
                         {
                             String newValue = relocate( attributeValue, relocators );
                             attributes.putValue( attribute, newValue );
                         }
                     }
                 }
             }
 
             manifestDiscovered = true;
         }
     }
 
     @Override
     public boolean hasTransformedResource()
     {
         return true;
     }
 
     @Override
     public void modifyOutputStream( JarOutputStream jos )
         throws IOException
     {
         // If we didn't find a manifest, then let's create one.
         if ( manifest == null )
         {
             manifest = new Manifest();
         }
 
         Attributes attributes = manifest.getMainAttributes();
 
         if ( mainClass != null )
         {
             attributes.put( Attributes.Name.MAIN_CLASS, mainClass );
         }
 
         if ( manifestEntries != null )
         {
             for ( Map.Entry<String, Object> entry : manifestEntries.entrySet() )
             {
                 attributes.put( new Attributes.Name( entry.getKey() ), entry.getValue() );
             }
         }
 
         jos.putNextEntry( new JarEntry( JarFile.MANIFEST_NAME ) );
         manifest.write( jos );
     }
     
     private String relocate( String originalValue, List<Relocator> relocators )
     {
         String newValue = originalValue;
         for ( Relocator relocator : relocators )
         {
             String value;
             do
             {
                 value = newValue;
                 newValue = relocator.relocateClass( value );
             }
             while ( !value.equals( newValue ) );
         }
         return newValue;
     }
 }