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.BufferedInputStream;
  import java.io.ByteArrayOutputStream;
  import java.io.IOException;
  import java.io.InputStream;
  import java.io.Reader;
  import java.io.Writer;
  import java.util.ArrayList;
  import java.util.List;
  import java.util.jar.JarEntry;
  import java.util.jar.JarOutputStream;
  
  import org.apache.maven.plugins.shade.relocation.Relocator;
  import org.codehaus.plexus.util.ReaderFactory;
  import org.codehaus.plexus.util.WriterFactory;
  import org.codehaus.plexus.util.xml.Xpp3Dom;
  import org.codehaus.plexus.util.xml.Xpp3DomBuilder;
  import org.codehaus.plexus.util.xml.Xpp3DomWriter;
  
  /**
   * A resource processor that aggregates Maven <code>plugin.xml</code> files.
   * 
   * @author Robert Scholte
   * @since 3.0
   */
  public class PluginXmlResourceTransformer
      implements ResourceTransformer
  {
      private List<Xpp3Dom> mojos = new ArrayList<>();
  
      public static final String PLUGIN_XML_PATH = "META-INF/maven/plugin.xml";
  
      public boolean canTransformResource( String resource )
      {
          return PLUGIN_XML_PATH.equals( resource );
      }
  
      public void processResource( String resource, InputStream is, List<Relocator> relocators )
          throws IOException
      {
          Xpp3Dom newDom;
  
          try
          {
              BufferedInputStream bis = new BufferedInputStream( is )
              {
                  public void close()
                      throws IOException
                  {
                      // leave ZIP open
                  }
              };
  
              Reader reader = ReaderFactory.newXmlReader( bis );
  
              newDom = Xpp3DomBuilder.build( reader );
          }
          catch ( Exception e )
          {
              throw new IOException( "Error parsing plugin.xml in " + is, e );
          }
  
          // Only try to merge in mojos if there are some elements in the plugin
          if ( newDom.getChild( "mojos" ) == null )
          {
              return;
          }
  
          for ( Xpp3Dom mojo : newDom.getChild( "mojos" ).getChildren( "mojo" ) )
          {
  
              String impl = getValue( mojo, "implementation" );
              impl = getRelocatedClass( impl, relocators );
              setValue( mojo, "implementation", impl );
  
              Xpp3Dom parameters = mojo.getChild( "parameters" );
              if ( parameters != null )
              {
                  for ( Xpp3Dom parameter : parameters.getChildren() )
                 {
                     String type = getValue( parameter, "type" );
                     type = getRelocatedClass( type, relocators );
                     setValue( parameter, "type", type );
                 }
             }
 
             Xpp3Dom configuration = mojo.getChild( "configuration" );
             if ( configuration != null )
             {
                 for ( Xpp3Dom configurationEntry : configuration.getChildren() )
                 {
                     String implementation = getAttribute( configurationEntry, "implementation" );
                     implementation = getRelocatedClass( implementation, relocators );
                     setAttribute( configurationEntry, "implementation", implementation );
                 }
             }
 
             Xpp3Dom requirements = mojo.getChild( "requirements" );
             if ( requirements != null && requirements.getChildCount() > 0 )
             {
                 for ( Xpp3Dom requirement : requirements.getChildren() )
                 {
                     String requiredRole = getValue( requirement, "role" );
                     requiredRole = getRelocatedClass( requiredRole, relocators );
                     setValue( requirement, "role", requiredRole );
                 }
             }
             mojos.add( mojo );
         }
     }
 
     public void modifyOutputStream( JarOutputStream jos )
         throws IOException
     {
         byte[] data = getTransformedResource();
 
         jos.putNextEntry( new JarEntry( PLUGIN_XML_PATH ) );
 
         jos.write( data );
 
         mojos.clear();
     }
 
     public boolean hasTransformedResource()
     {
         return !mojos.isEmpty();
     }
 
     byte[] getTransformedResource()
         throws IOException
     {
         ByteArrayOutputStream baos = new ByteArrayOutputStream( 1024 * 4 );
 
         try ( Writer writer = WriterFactory.newXmlWriter( baos ) )
         {
             Xpp3Dom dom = new Xpp3Dom( "plugin" );
 
             Xpp3Dom componentDom = new Xpp3Dom( "mojos" );
 
             dom.addChild( componentDom );
 
             for ( Xpp3Dom mojo : mojos )
             {
                 componentDom.addChild( mojo );
             }
 
             Xpp3DomWriter.write( writer, dom );
         }
 
         return baos.toByteArray();
     }
 
     private String getRelocatedClass( String className, List<Relocator> relocators )
     {
         if ( className != null && className.length() > 0 && relocators != null )
         {
             for ( Relocator relocator : relocators )
             {
                 if ( relocator.canRelocateClass( className ) )
                 {
                     return relocator.relocateClass( className );
                 }
             }
         }
 
         return className;
     }
 
     private static String getValue( Xpp3Dom dom, String element )
     {
         Xpp3Dom child = dom.getChild( element );
 
         return ( child != null && child.getValue() != null ) ? child.getValue() : "";
     }
 
     private static void setValue( Xpp3Dom dom, String element, String value )
     {
         Xpp3Dom child = dom.getChild( element );
 
         if ( child == null || value == null || value.length() <= 0 )
         {
             return;
         }
 
         child.setValue( value );
     }
 
     private static String getAttribute( Xpp3Dom dom, String attribute )
     {
         return ( dom.getAttribute( attribute ) != null ) ? dom.getAttribute( attribute ) : "";
     }
 
     private static void setAttribute( Xpp3Dom dom, String attribute, String value )
     {
         String attr = dom.getAttribute( attribute );
 
         if ( attr == null || value == null || value.length() <= 0 )
         {
             return;
         }
 
         dom.setAttribute( attribute, value );
     }
 
 }