content: /*
   * Copyright (C) 2010. All rights reserved.
   */
  package ro.isdc.wro.extensions.processor.css;
  
  import java.io.IOException;
  import java.io.Reader;
  import java.io.Writer;
  
  import org.apache.commons.io.IOUtils;
  import org.apache.commons.lang3.StringUtils;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import ro.isdc.wro.WroRuntimeException;
  import ro.isdc.wro.extensions.processor.support.ObjectPoolHelper;
  import ro.isdc.wro.extensions.processor.support.sass.SassCss;
  import ro.isdc.wro.model.resource.Resource;
  import ro.isdc.wro.model.resource.ResourceType;
  import ro.isdc.wro.model.resource.SupportedResourceType;
  import ro.isdc.wro.model.resource.processor.Destroyable;
  import ro.isdc.wro.model.resource.processor.ResourcePostProcessor;
  import ro.isdc.wro.model.resource.processor.ResourcePreProcessor;
  import ro.isdc.wro.util.ObjectFactory;
  
  
  /**
   * A processor using sass engine:
   *
   * @author Alex Objelean
   * @created 27 Oct 2010
   */
  @SupportedResourceType(ResourceType.CSS)
  public class SassCssProcessor
      implements ResourcePreProcessor, ResourcePostProcessor, Destroyable {
    private static final Logger LOG = LoggerFactory.getLogger(SassCssProcessor.class);
    public static final String ALIAS = "sassCss";
    public static final String ALIAS_RUBY = "rubySassCss";
  
  
    private ObjectPoolHelper<SassCss> enginePool;
  
    /**
     * default constructor that sets the engine used to RHINO for backwards compatibility.
     */
    public SassCssProcessor() {
      enginePool = new ObjectPoolHelper<SassCss>(new ObjectFactory<SassCss>() {
        @Override
        public SassCss create() {
          return newEngine();
        }
      });
    }
  
    /**
     * {@inheritDoc}
     */
    @Override
    public void process(final Resource resource, final Reader reader, final Writer writer)
        throws IOException {
      final String content = IOUtils.toString(reader);
      final SassCss engine = enginePool.getObject();
      try {
        writer.write(engine.process(content));
      } catch (final WroRuntimeException e) {
        final String resourceUri = resource == null ? StringUtils.EMPTY : "[" + resource.getUri() + "]";
        LOG.error("Exception while applying " + SassCss.class.getClass().getSimpleName() + " processor on the " + resourceUri
            + " resource, no processing applied...", e);
        onException(e);
        writer.write(content);
      } finally {
        reader.close();
        writer.close();
        try {
          enginePool.returnObject(engine);
        } catch (final Exception e) {
          //should never happen
          LOG.error("Cannot return lessCss engine to the pool", e);
        }
      }
    }
  
    /**
     * Invoked when a processing exception occurs. By default the exception is thrown further.
     */
    protected void onException(final WroRuntimeException e) {
      throw e;
    }
  
    /**
     * Method for processing with Rhino based engine
     *
     * @param content
     * @return
     */
    protected SassCss newEngine() {
      return new SassCss();
    }
  
    /**
     * {@inheritDoc}
     */
    @Override
    public void process(final Reader reader, final Writer writer)
        throws IOException {
      process(null, reader, writer);
    }
  
    @Override
    public void destroy() throws Exception {
      enginePool.destroy();
    }
  }
  