tikhomirov@115: /*
tikhomirov@115:  * Copyright (c) 2011 TMate Software Ltd
tikhomirov@115:  *  
tikhomirov@115:  * This program is free software; you can redistribute it and/or modify
tikhomirov@115:  * it under the terms of the GNU General Public License as published by
tikhomirov@115:  * the Free Software Foundation; version 2 of the License.
tikhomirov@115:  *
tikhomirov@115:  * This program is distributed in the hope that it will be useful,
tikhomirov@115:  * but WITHOUT ANY WARRANTY; without even the implied warranty of
tikhomirov@115:  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
tikhomirov@115:  * GNU General Public License for more details.
tikhomirov@115:  *
tikhomirov@115:  * For information on how to redistribute this software under
tikhomirov@115:  * the terms of a license other than GNU General Public License
tikhomirov@130:  * contact TMate Software at support@hg4j.com
tikhomirov@115:  */
tikhomirov@115: package org.tmatesoft.hg.internal;
tikhomirov@115: 
tikhomirov@148: import java.io.IOException;
tikhomirov@115: import java.nio.ByteBuffer;
tikhomirov@355: import java.util.ArrayList;
tikhomirov@115: import java.util.Collection;
tikhomirov@355: import java.util.List;
tikhomirov@115: 
tikhomirov@157: import org.tmatesoft.hg.util.Adaptable;
tikhomirov@115: import org.tmatesoft.hg.util.ByteChannel;
tikhomirov@148: import org.tmatesoft.hg.util.CancelledException;
tikhomirov@115: 
tikhomirov@115: /**
tikhomirov@115:  *
tikhomirov@115:  * @author Artem Tikhomirov
tikhomirov@115:  * @author TMate Software Ltd.
tikhomirov@115:  */
tikhomirov@157: public class FilterByteChannel implements ByteChannel, Adaptable {
tikhomirov@115: 	private final Filter[] filters;
tikhomirov@115: 	private final ByteChannel delegate;
tikhomirov@115: 	
tikhomirov@115: 	public FilterByteChannel(ByteChannel delegateChannel, Collection<Filter> filtersToApply) {
tikhomirov@115: 		if (delegateChannel == null || filtersToApply == null) {
tikhomirov@115: 			throw new IllegalArgumentException();
tikhomirov@115: 		}
tikhomirov@115: 		delegate = delegateChannel;
tikhomirov@115: 		filters = filtersToApply.toArray(new Filter[filtersToApply.size()]);
tikhomirov@115: 	}
tikhomirov@115: 
tikhomirov@148: 	public int write(ByteBuffer buffer) throws IOException, CancelledException {
tikhomirov@115: 		final int srcPos = buffer.position();
tikhomirov@115: 		ByteBuffer processed = buffer;
tikhomirov@115: 		for (Filter f : filters) {
tikhomirov@115: 			// each next filter consumes not more than previous
tikhomirov@115: 			// hence total consumed equals position shift in the original buffer
tikhomirov@115: 			processed = f.filter(processed);
tikhomirov@115: 		}
tikhomirov@115: 		delegate.write(processed);
tikhomirov@115: 		return buffer.position() - srcPos; // consumed as much from original buffer
tikhomirov@115: 	}
tikhomirov@115: 
tikhomirov@157: 	// adapters or implemented interfaces of the original class shall not be obfuscated by filter
tikhomirov@157: 	public <T> T getAdapter(Class<T> adapterClass) {
tikhomirov@355: 		if (adapterClass == Preview.class) {
tikhomirov@355: 			ArrayList<Preview> previewers = new ArrayList<Preview>(filters.length);
tikhomirov@356: 			Adaptable.Factory<Preview> factory = new Adaptable.Factory<Preview>(Preview.class);
tikhomirov@355: 			for (Filter f : filters) {
tikhomirov@356: 				Preview p = factory.get(f);
tikhomirov@356: 				if (p != null) {
tikhomirov@356: 					previewers.add(p);
tikhomirov@355: 				}
tikhomirov@355: 			}
tikhomirov@355: 			if (!previewers.isEmpty()) {
tikhomirov@355: 				@SuppressWarnings("unchecked")
tikhomirov@355: 				T rv = (T) new PreviewSupport(previewers);
tikhomirov@355: 				return rv;
tikhomirov@355: 			}
tikhomirov@355: 			// fall through to let delegate answer
tikhomirov@355: 		}
tikhomirov@356: 		return Adaptable.Factory.getAdapter(delegate, adapterClass, null);
tikhomirov@157: 	}
tikhomirov@355: 
tikhomirov@355: 	private static class PreviewSupport implements Preview {
tikhomirov@355: 		private final Preview[] participants;
tikhomirov@355: 
tikhomirov@355: 		public PreviewSupport(List<Preview> previewers) {
tikhomirov@355: 			participants = new Preview[previewers.size()];
tikhomirov@355: 			previewers.toArray(participants);
tikhomirov@355: 		}
tikhomirov@355: 		
tikhomirov@355: 		public void preview(ByteBuffer src) {
tikhomirov@355: 			final int originalPos = src.position();
tikhomirov@355: 			for (Preview p : participants) {
tikhomirov@355: 				p.preview(src);
tikhomirov@355: 				// reset to initial state
tikhomirov@355: 				src.position(originalPos);
tikhomirov@355: 			}
tikhomirov@355: 		}
tikhomirov@355: 	}
tikhomirov@115: }