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   /*
    * Copyright 2019 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;
  
  import io.netty.buffer.ByteBuf;
  import io.netty.buffer.Unpooled;
  import io.netty.util.CharsetUtil;
  import io.netty.util.internal.StringUtil;
  
  /**
   * Web Socket Frame for closing the connection.
   */
  public class CloseWebSocketFrame extends WebSocketFrame {
  
      /**
       * Creates a new empty close frame.
       */
      public CloseWebSocketFrame() {
          super(Unpooled.buffer(0));
      }
  
      /**
       * Creates a new empty close frame with closing status code and reason text
       *
       * @param status
       *            Status code as per <a href="https://tools.ietf.org/html/rfc6455#section-7.4">RFC 6455</a>. For
       *            example, <tt>1000</tt> indicates normal closure.
       */
      public CloseWebSocketFrame(WebSocketCloseStatus status) {
          this(requireValidStatusCode(status.code()), status.reasonText());
      }
  
      /**
       * Creates a new empty close frame with closing status code and reason text
       *
       * @param status
       *            Status code as per <a href="https://tools.ietf.org/html/rfc6455#section-7.4">RFC 6455</a>. For
       *            example, <tt>1000</tt> indicates normal closure.
       * @param reasonText
       *            Reason text. Set to null if no text.
       */
      public CloseWebSocketFrame(WebSocketCloseStatus status, String reasonText) {
          this(requireValidStatusCode(status.code()), reasonText);
      }
  
      /**
       * Creates a new empty close frame with closing status code and reason text
       *
       * @param statusCode
       *            Integer status code as per <a href="https://tools.ietf.org/html/rfc6455#section-7.4">RFC 6455</a>. For
       *            example, <tt>1000</tt> indicates normal closure.
       * @param reasonText
       *            Reason text. Set to null if no text.
       */
      public CloseWebSocketFrame(int statusCode, String reasonText) {
          this(true, 0, requireValidStatusCode(statusCode), reasonText);
      }
  
      /**
       * Creates a new close frame with no losing status code and no reason text
       *
       * @param finalFragment
       *            flag indicating if this frame is the final fragment
       * @param rsv
       *            reserved bits used for protocol extensions.
       */
      public CloseWebSocketFrame(boolean finalFragment, int rsv) {
          this(finalFragment, rsv, Unpooled.buffer(0));
      }
  
      /**
       * Creates a new close frame with closing status code and reason text
       *
       * @param finalFragment
       *            flag indicating if this frame is the final fragment
       * @param rsv
       *            reserved bits used for protocol extensions
       * @param statusCode
       *            Integer status code as per <a href="https://tools.ietf.org/html/rfc6455#section-7.4">RFC 6455</a>. For
       *            example, <tt>1000</tt> indicates normal closure.
       * @param reasonText
       *            Reason text. Set to null if no text.
       */
      public CloseWebSocketFrame(boolean finalFragment, int rsv, int statusCode, String reasonText) {
          super(finalFragment, rsv, newBinaryData(requireValidStatusCode(statusCode), reasonText));
      }
 
     private static ByteBuf newBinaryData(int statusCode, String reasonText) {
         if (reasonText == null) {
             reasonText = StringUtil.EMPTY_STRING;
         }
 
         ByteBuf binaryData = Unpooled.buffer(2 + reasonText.length());
         binaryData.writeShort(statusCode);
         if (!reasonText.isEmpty()) {
             binaryData.writeCharSequence(reasonText, CharsetUtil.UTF_8);
         }
         return binaryData;
     }
 
     /**
      * Creates a new close frame
      *
      * @param finalFragment
      *            flag indicating if this frame is the final fragment
      * @param rsv
      *            reserved bits used for protocol extensions
      * @param binaryData
      *            the content of the frame. Must be 2 byte integer followed by optional UTF-8 encoded string.
      */
     public CloseWebSocketFrame(boolean finalFragment, int rsv, ByteBuf binaryData) {
         super(finalFragment, rsv, binaryData);
     }
 
     /**
      * Returns the closing status code as per <a href="https://tools.ietf.org/html/rfc6455#section-7.4">RFC 6455</a>. If
      * a status code is set, -1 is returned.
      */
     public int statusCode() {
         ByteBuf binaryData = content();
         if (binaryData == null || binaryData.readableBytes() < 2) {
             return -1;
         }
 
         return binaryData.getUnsignedShort(binaryData.readerIndex());
     }
 
     /**
      * Returns the reason text as per <a href="https://tools.ietf.org/html/rfc6455#section-7.4">RFC 6455</a> If a reason
      * text is not supplied, an empty string is returned.
      */
     public String reasonText() {
         ByteBuf binaryData = content();
         if (binaryData == null || binaryData.readableBytes() <= 2) {
             return "";
         }
 
         return binaryData.toString(binaryData.readerIndex() + 2, binaryData.readableBytes() - 2, CharsetUtil.UTF_8);
     }
 
     @Override
     public CloseWebSocketFrame copy() {
         return (CloseWebSocketFrame) super.copy();
     }
 
     @Override
     public CloseWebSocketFrame duplicate() {
         return (CloseWebSocketFrame) super.duplicate();
     }
 
     @Override
     public CloseWebSocketFrame retainedDuplicate() {
         return (CloseWebSocketFrame) super.retainedDuplicate();
     }
 
     @Override
     public CloseWebSocketFrame replace(ByteBuf content) {
         return new CloseWebSocketFrame(isFinalFragment(), rsv(), content);
     }
 
     @Override
     public CloseWebSocketFrame retain() {
         super.retain();
         return this;
     }
 
     @Override
     public CloseWebSocketFrame retain(int increment) {
         super.retain(increment);
         return this;
     }
 
     @Override
     public CloseWebSocketFrame touch() {
         super.touch();
         return this;
     }
 
     @Override
     public CloseWebSocketFrame touch(Object hint) {
         super.touch(hint);
         return this;
     }
 
     static int requireValidStatusCode(int statusCode) {
         if (WebSocketCloseStatus.isValidStatusCode(statusCode)) {
             return statusCode;
         } else {
             throw new IllegalArgumentException("WebSocket close status code does NOT comply with RFC-6455: " +
                     statusCode);
         }
     }
 }