package org.apache.maven.scm.provider.accurev.cli;
   
   /*
    * 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.Reader;
  import java.io.Writer;
  import java.nio.channels.Channels;
  import java.nio.channels.Pipe;
  import java.nio.channels.Pipe.SinkChannel;
  import java.nio.channels.Pipe.SourceChannel;
  import java.nio.charset.Charset;
  import java.util.ArrayList;
  import java.util.Arrays;
  import java.util.HashMap;
  import java.util.List;
  import java.util.Map;
  
  import org.apache.maven.scm.log.ScmLogger;
  import org.codehaus.plexus.util.cli.StreamConsumer;
  import org.codehaus.plexus.util.xml.pull.MXParser;
  import org.codehaus.plexus.util.xml.pull.XmlPullParser;
  import org.codehaus.plexus.util.xml.pull.XmlPullParserException;
  
  /**
   * This class is required because Plexus command line won't let you get to the process stream output process.
   * 
   * @author ggardner
   */
  public abstract class XppStreamConsumer
      extends Thread
      implements StreamConsumer
  
  {
      public ScmLogger getLogger()
      {
          return logger;
      }
  
      private Writer writer;
  
      private XmlPullParser parser = new MXParser();
  
      private volatile boolean complete = false;
  
      private ScmLogger logger;
  
      private int lineCount = 0;
  
      private Reader reader;
  
      public XppStreamConsumer( ScmLogger logger )
      {
  
          super();
          this.logger = logger;
          try
          {
              Pipe p = Pipe.open();
              SinkChannel sink = p.sink();
              SourceChannel source = p.source();
              writer = Channels.newWriter( sink, Charset.defaultCharset().name() );
              reader = Channels.newReader( source, Charset.defaultCharset().name() );
              parser.setInput( reader );
  
          }
          catch ( Exception e )
          {
              logger.error( "Exception initialising pipe", e );
          }
  
      }
  
      public final void consumeLine( String line )
      {
          // Do not debug line here - as CommandOutputConsumer wraps this and uses
          // the same logger
          try
          {
              writer.append( line );
              if ( lineCount == 0 )
              {
                 this.start();
             }
             lineCount++;
             writer.flush();
         }
         catch ( IOException e )
         {
             throw new RuntimeException( "error pumping line to pipe", e );
         }
 
     }
 
     @Override
     public void run()
     {
 
         try
         {
             parse( parser );
         }
         catch ( Exception e )
         {
             caughtParseException( e );
         }
         finally
         {
             synchronized ( this )
             {
                 
                 try
                 {
                     reader.close();
                 }
                 catch ( IOException e )
                 {
                     getLogger().warn( "Error closing pipe reader", e );
                 }
                 
                 complete = true;
                 this.notifyAll();
             }
         }
     }
 
     protected void caughtParseException( Exception e )
     {
         logger.warn( "Exception parsing input", e );
 
     }
 
     protected void parse( XmlPullParser p )
         throws XmlPullParserException, IOException
     {
         List<String> tagPath = new ArrayList<String>();
         int eventType = p.getEventType();
         if ( logger.isDebugEnabled() )
         {
             logger.debug( "Event " + eventType );
         }
 
         while ( eventType != XmlPullParser.END_DOCUMENT )
         {
             int lastIndex = tagPath.size() - 1;
             String tagName;
             switch ( eventType )
             {
                 case XmlPullParser.START_DOCUMENT:
 
                     break;
 
                 case XmlPullParser.START_TAG:
                     tagName = p.getName();
                     if ( tagName != null )
                     {
                         tagPath.add( tagName );
                         int attributeCount = p.getAttributeCount();
                         Map<String, String> attributes = new HashMap<String, String>( Math.max( attributeCount, 0 ) );
                         for ( int i = 0; i < attributeCount; i++ )
                         {
                             attributes.put( p.getAttributeName( i ), p.getAttributeValue( i ) );
                         }
 
                         startTag( tagPath, attributes );
                     }
                     break;
 
                 case XmlPullParser.TEXT:
                     if ( !p.isWhitespace() )
                     {
                         String text = p.getText();
                         text( tagPath, text );
                     }
                     break;
 
                 case XmlPullParser.END_TAG:
                     tagName = p.getName();
 
                     if ( lastIndex < 0 || !tagName.equals( tagPath.get( lastIndex ) ) )
                     {
                         logger.warn( "Bad tag path: " + Arrays.toString( tagPath.toArray() ) );
                     }
                     endTag( tagPath );
                     tagPath.remove( lastIndex );
                     break;
 
                 default:
                     logger.warn( "Unexpected event type " + eventType );
                     break;
             }
             p.next();
             eventType = p.getEventType();
             if ( logger.isDebugEnabled() )
             {
                 logger.debug( "Event " + eventType );
             }
         }
     }
 
     /**
      * close the input and wait for parsing to complete
      */
     public void waitComplete()
     {
         Thread.yield();
         try
         {
             writer.close();
         }
         catch ( IOException e1 )
         {
             logger.warn( "Exception flushing output", e1 );
         }
 
         while ( !isComplete() )
         {
             synchronized ( this )
             {
                 try
                 {
                     if ( !isComplete() )
                     {
                         this.wait( 1000 );
                     }
                 }
                 catch ( Exception e )
                 {
                     logger.warn( e );
                 }
             }
         }
 
     }
 
     private boolean isComplete()
     {
         return complete || lineCount == 0;
     }
 
     protected void startTag( List<String> tagPath, Map<String, String> attributes )
     {
         if ( logger.isDebugEnabled() )
         {
             String tagName = getTagName( tagPath );
             logger.debug( "START_TAG: " + tagName + "(" + attributes.size() + ")" );
         }
     }
 
     protected static String getTagName( List<String> tagPath )
     {
         return tagPath.size() == 0 ? null : tagPath.get( tagPath.size() - 1 );
     }
 
     protected void endTag( List<String> tagPath )
     {
         if ( logger.isDebugEnabled() )
         {
             logger.debug( "END_TAG: " + getTagName( tagPath ) );
         }
     }
 
     protected void text( List<String> tagPath, String text )
     {
         if ( logger.isDebugEnabled() )
         {
             logger.debug( "TEXT: " + text );
         }
     }
 
 }