/*
    * 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.channel.kqueue;
  
  import io.netty.channel.Channel;
  import io.netty.channel.ChannelConfig;
  import io.netty.channel.ChannelMetadata;
  import io.netty.channel.ChannelOutboundBuffer;
  import io.netty.channel.ChannelPipeline;
  import io.netty.channel.EventLoop;
  import io.netty.channel.ServerChannel;
  import io.netty.util.internal.UnstableApi;
  
  import java.net.InetSocketAddress;
  import java.net.SocketAddress;
  
  @UnstableApi
  public abstract class AbstractKQueueServerChannel extends AbstractKQueueChannel implements ServerChannel {
      private static final ChannelMetadata METADATA = new ChannelMetadata(false, 16);
  
      AbstractKQueueServerChannel(BsdSocket fd) {
          this(fd, isSoErrorZero(fd));
      }
  
      AbstractKQueueServerChannel(BsdSocket fd, boolean active) {
          super(null, fd, active);
      }
  
      @Override
      public ChannelMetadata metadata() {
          return METADATA;
      }
  
      @Override
      protected boolean isCompatible(EventLoop loop) {
          return loop instanceof KQueueEventLoop;
      }
  
      @Override
      protected InetSocketAddress remoteAddress0() {
          return null;
      }
  
      @Override
      protected AbstractKQueueUnsafe newUnsafe() {
          return new KQueueServerSocketUnsafe();
      }
  
      @Override
      protected void doWrite(ChannelOutboundBuffer in) throws Exception {
          throw new UnsupportedOperationException();
      }
  
      @Override
      protected Object filterOutboundMessage(Object msg) throws Exception {
          throw new UnsupportedOperationException();
      }
  
      abstract Channel newChildChannel(int fd, byte[] remote, int offset, int len) throws Exception;
  
      @Override
      protected boolean doConnect(SocketAddress remoteAddress, SocketAddress localAddress) throws Exception {
          throw new UnsupportedOperationException();
      }
  
      final class KQueueServerSocketUnsafe extends AbstractKQueueUnsafe {
          // Will hold the remote address after accept(...) was successful.
          // We need 24 bytes for the address as maximum + 1 byte for storing the capacity.
          // So use 26 bytes as it's a power of two.
          private final byte[] acceptedAddress = new byte[26];
  
          @Override
          void readReady(KQueueRecvByteAllocatorHandle allocHandle) {
              assert eventLoop().inEventLoop();
              final ChannelConfig config = config();
              if (shouldBreakReadReady(config)) {
                  clearReadFilter0();
                  return;
              }
              final ChannelPipeline pipeline = pipeline();
              allocHandle.reset(config);
              allocHandle.attemptedBytesRead(1);
              readReadyBefore();
  
              Throwable exception = null;
              try {
                 try {
                     do {
                         int acceptFd = socket.accept(acceptedAddress);
                         if (acceptFd == -1) {
                             // this means everything was handled for now
                             allocHandle.lastBytesRead(-1);
                             break;
                         }
                         allocHandle.lastBytesRead(1);
                         allocHandle.incMessagesRead(1);
 
                         readPending = false;
                         pipeline.fireChannelRead(newChildChannel(acceptFd, acceptedAddress, 1,
                                                                  acceptedAddress[0]));
                     } while (allocHandle.continueReading());
                 } catch (Throwable t) {
                     exception = t;
                 }
                 allocHandle.readComplete();
                 pipeline.fireChannelReadComplete();
 
                 if (exception != null) {
                     pipeline.fireExceptionCaught(exception);
                 }
             } finally {
                 readReadyFinally(config);
             }
         }
     }
 }