/*
    * Copyright 2016 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.smtp;
  
  import io.netty.buffer.ByteBuf;
  import io.netty.buffer.Unpooled;
  import io.netty.util.internal.UnstableApi;
  
  /**
   * The last part of a sequence of {@link SmtpContent}s that are sent after a {@code DATA} request.
   * Be aware that a {@link SmtpContent} / {@link LastSmtpContent} sequence must always use CRLF as line delimiter
   * and the lines that start with a DOT must be escaped with an extra DOT as
   * specified by <a href="https://www.ietf.org/rfc/rfc2821.txt">RFC2821</a>.
   */
  @UnstableApi
  public interface LastSmtpContent extends SmtpContent {
  
      /**
       * Empty {@link LastSmtpContent}.
       */
      LastSmtpContent EMPTY_LAST_CONTENT = new LastSmtpContent() {
          @Override
          public LastSmtpContent copy() {
              return this;
          }
  
          @Override
          public LastSmtpContent duplicate() {
              return this;
          }
  
          @Override
          public LastSmtpContent retainedDuplicate() {
              return this;
          }
  
          @Override
          public LastSmtpContent replace(ByteBuf content) {
              return new DefaultLastSmtpContent(content);
          }
  
          @Override
          public LastSmtpContent retain() {
              return this;
          }
  
          @Override
          public LastSmtpContent retain(int increment) {
              return this;
          }
  
          @Override
          public LastSmtpContent touch() {
              return this;
          }
  
          @Override
          public LastSmtpContent touch(Object hint) {
              return this;
          }
  
          @Override
          public ByteBuf content() {
              return Unpooled.EMPTY_BUFFER;
          }
  
          @Override
          public int refCnt() {
              return 1;
          }
  
          @Override
          public boolean release() {
              return false;
          }
  
          @Override
          public boolean release(int decrement) {
              return false;
          }
      };
  
      @Override
      LastSmtpContent copy();
  
      @Override
     LastSmtpContent duplicate();
 
     @Override
     LastSmtpContent retainedDuplicate();
 
     @Override
     LastSmtpContent replace(ByteBuf content);
 
     @Override
     LastSmtpContent retain();
 
     @Override
     LastSmtpContent retain(int increment);
 
     @Override
     LastSmtpContent touch();
 
     @Override
     LastSmtpContent touch(Object hint);
 }