/*
    * 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.channel.epoll;
  
  import io.netty.channel.Channel;
  import io.netty.channel.EventLoop;
  import io.netty.channel.socket.InternetProtocolFamily;
  import io.netty.channel.socket.ServerSocketChannel;
  
  import java.io.IOException;
  import java.net.InetAddress;
  import java.net.InetSocketAddress;
  import java.net.SocketAddress;
  import java.util.Collection;
  import java.util.Collections;
  import java.util.Map;
  
  import static io.netty.channel.epoll.LinuxSocket.newSocketStream;
  import static io.netty.channel.epoll.Native.IS_SUPPORTING_TCP_FASTOPEN_SERVER;
  import static io.netty.channel.unix.NativeInetAddress.address;
  
  /**
   * {@link ServerSocketChannel} implementation that uses linux EPOLL Edge-Triggered Mode for
   * maximal performance.
   */
  public final class EpollServerSocketChannel extends AbstractEpollServerChannel implements ServerSocketChannel {
  
      private final EpollServerSocketChannelConfig config;
      private volatile Collection<InetAddress> tcpMd5SigAddresses = Collections.emptyList();
  
      public EpollServerSocketChannel() {
          this((InternetProtocolFamily) null);
      }
  
      public EpollServerSocketChannel(InternetProtocolFamily protocol) {
          super(newSocketStream(protocol), false);
          config = new EpollServerSocketChannelConfig(this);
      }
  
      public EpollServerSocketChannel(int fd) {
          // Must call this constructor to ensure this object's local address is configured correctly.
          // The local address can only be obtained from a Socket object.
          this(new LinuxSocket(fd));
      }
  
      EpollServerSocketChannel(LinuxSocket fd) {
          super(fd);
          config = new EpollServerSocketChannelConfig(this);
      }
  
      EpollServerSocketChannel(LinuxSocket fd, boolean active) {
          super(fd, active);
          config = new EpollServerSocketChannelConfig(this);
      }
  
      @Override
      protected boolean isCompatible(EventLoop loop) {
          return loop instanceof EpollEventLoop;
      }
  
      @Override
      protected void doBind(SocketAddress localAddress) throws Exception {
          super.doBind(localAddress);
          final int tcpFastopen;
          if (IS_SUPPORTING_TCP_FASTOPEN_SERVER && (tcpFastopen = config.getTcpFastopen()) > 0) {
              socket.setTcpFastOpen(tcpFastopen);
          }
          socket.listen(config.getBacklog());
          active = true;
      }
  
      @Override
      public InetSocketAddress remoteAddress() {
          return (InetSocketAddress) super.remoteAddress();
      }
  
      @Override
      public InetSocketAddress localAddress() {
          return (InetSocketAddress) super.localAddress();
      }
  
      @Override
      public EpollServerSocketChannelConfig config() {
          return config;
      }
  
     @Override
     protected Channel newChildChannel(int fd, byte[] address, int offset, int len) throws Exception {
         return new EpollSocketChannel(this, new LinuxSocket(fd), address(address, offset, len));
     }
 
     Collection<InetAddress> tcpMd5SigAddresses() {
         return tcpMd5SigAddresses;
     }
 
     void setTcpMd5Sig(Map<InetAddress, byte[]> keys) throws IOException {
         // Add synchronized as newTcpMp5Sigs might do multiple operations on the socket itself.
         synchronized (this) {
             tcpMd5SigAddresses = TcpMd5Util.newTcpMd5Sigs(this, tcpMd5SigAddresses, keys);
         }
     }
 }