code: public static void processFile( String input, String mappingPath, String outputFile, boolean doPrune, Log log ) throws IOException
  	{
  		Set<String> usedClassNames = new HashSet<>();
  
  		input = replaceClassNames( input, mappingPath, usedClassNames, log );
  
  		log.debug( usedClassNames.size() + " used css classes in the mapping file" );
  		log.debug( "used css classes : " + usedClassNames );
  
  		CssRewriter cssRewriter = new CssRewriter( usedClassNames, doPrune, log );
  		input = cssRewriter.process( input );
  
  		input += "\r\n// generated by HexaCss maven plugin, see http://www.lteconsulting.fr/hexacss";
  
  		writeFile( outputFile, input, log );
  	}
docs: Process an input file
  
  @throws IOException In case there is a problem
  
  @param input
  The input file content
  @param mappingPath
  The file containing mapping information (lines in the form of
  newName=oldName)
  @param outputFile
  Path to the output file
  @param doPrune
  <code>true</code> if pruning unused CSS rules is needed
  @param log
  Maven logger