/*
    * Copyright 2014 The Netty Project
    *
    * The Netty Project 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:
    *
    *   https://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 io.netty.handler.codec.http.websocketx.extensions.compression;
  
  import io.netty.handler.codec.http.websocketx.BinaryWebSocketFrame;
  import io.netty.handler.codec.http.websocketx.ContinuationWebSocketFrame;
  import io.netty.handler.codec.http.websocketx.TextWebSocketFrame;
  import io.netty.handler.codec.http.websocketx.WebSocketFrame;
  import io.netty.handler.codec.http.websocketx.extensions.WebSocketExtension;
  import io.netty.handler.codec.http.websocketx.extensions.WebSocketExtensionFilter;
  
  /**
   * Per-frame implementation of deflate compressor.
   */
  class PerFrameDeflateEncoder extends DeflateEncoder {
  
      /**
       * Constructor
       *
       * @param compressionLevel compression level of the compressor.
       * @param windowSize       maximum size of the window compressor buffer.
       * @param noContext        true to disable context takeover.
       */
      PerFrameDeflateEncoder(int compressionLevel, int windowSize, boolean noContext) {
          super(compressionLevel, windowSize, noContext, WebSocketExtensionFilter.NEVER_SKIP);
      }
  
      /**
       * Constructor
       *
       * @param compressionLevel compression level of the compressor.
       * @param windowSize       maximum size of the window compressor buffer.
       * @param noContext        true to disable context takeover.
       * @param extensionEncoderFilter extension encoder filter for per frame deflate encoder.
       */
      PerFrameDeflateEncoder(int compressionLevel, int windowSize, boolean noContext,
                             WebSocketExtensionFilter extensionEncoderFilter) {
          super(compressionLevel, windowSize, noContext, extensionEncoderFilter);
      }
  
      @Override
      public boolean acceptOutboundMessage(Object msg) throws Exception {
          if (!super.acceptOutboundMessage(msg)) {
              return false;
          }
  
          WebSocketFrame wsFrame = (WebSocketFrame) msg;
          if (extensionEncoderFilter().mustSkip(wsFrame)) {
              return false;
          }
  
          return (msg instanceof TextWebSocketFrame || msg instanceof BinaryWebSocketFrame ||
                  msg instanceof ContinuationWebSocketFrame) &&
                 wsFrame.content().readableBytes() > 0 &&
                 (wsFrame.rsv() & WebSocketExtension.RSV1) == 0;
      }
  
      @Override
      protected int rsv(WebSocketFrame msg) {
          return msg.rsv() | WebSocketExtension.RSV1;
      }
  
      @Override
      protected boolean removeFrameTail(WebSocketFrame msg) {
          return true;
      }
  
  }