FrameDecoderHandler.java

/*******************************************************************************
 * Copyright (c) 2016 comtel inc.
 *
 * Licensed 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.
 *******************************************************************************/
package org.jfxvnc.net.rfb.codec.decoder;

import java.util.EnumMap;
import java.util.List;

import org.jfxvnc.net.rfb.codec.Encoding;
import org.jfxvnc.net.rfb.codec.PixelFormat;
import org.jfxvnc.net.rfb.codec.ServerEvent;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import io.netty.buffer.ByteBuf;
import io.netty.channel.ChannelHandlerContext;
import io.netty.handler.codec.ByteToMessageDecoder;

public class FrameDecoderHandler extends ByteToMessageDecoder {
  private static Logger logger = LoggerFactory.getLogger(FrameDecoderHandler.class);

  private final EnumMap<ServerEvent, FrameDecoder> frameDecoder = new EnumMap<>(ServerEvent.class);

  enum State {
    NEXT, FRAME
  }

  private State state = State.NEXT;

  private ServerEvent serverEvent;

  public FrameDecoderHandler(PixelFormat pixelFormat) {

    frameDecoder.put(ServerEvent.SET_COLOR_MAP_ENTRIES, new ColourMapEntriesDecoder());
    frameDecoder.put(ServerEvent.BELL, new BellDecoder());
    frameDecoder.put(ServerEvent.SERVER_CUT_TEXT, new ServerCutTextDecoder());
    frameDecoder.put(ServerEvent.FRAMEBUFFER_UPDATE, new FramebufferUpdateRectDecoder(pixelFormat));
  }

  public Encoding[] getSupportedEncodings() {
    return ((FramebufferUpdateRectDecoder) frameDecoder.get(ServerEvent.FRAMEBUFFER_UPDATE)).getSupportedEncodings();
  }

  public boolean isPixelFormatSupported() {
    return ((FramebufferUpdateRectDecoder) frameDecoder.get(ServerEvent.FRAMEBUFFER_UPDATE)).isPixelFormatSupported();
  }

  @Override
  protected void decode(ChannelHandlerContext ctx, ByteBuf in, List<Object> out) throws Exception {
    if (!in.isReadable()) {
      return;
    }

    FrameDecoder decoder;
    switch (state) {
      case NEXT:
        serverEvent = ServerEvent.valueOf(in.getUnsignedByte(0));
        decoder = frameDecoder.get(serverEvent);

        if (decoder == null) {
          logger.error("not handled server message type: {} ({})", serverEvent, in.getUnsignedByte(0));
          in.skipBytes(in.readableBytes());
          return;
        }
        if (!decoder.decode(ctx, in, out)) {
          state = State.FRAME;
        }
      case FRAME:
        decoder = frameDecoder.get(serverEvent);

        if (decoder == null) {
          logger.error("not handled server message type: {} ({})", serverEvent, in.getUnsignedByte(0));
          in.skipBytes(in.readableBytes());
          return;
        }
        if (decoder.decode(ctx, in, out)) {
          state = State.NEXT;
        }
        break;
      default:
        logger.warn("unknown state: {}", state);
        break;
    }
  }

}