/*
    *  Licensed to the Apache Software Foundation (ASF) under one
    *  or more contributor license agreements.  See the NOTICE file
    *  distributed with this work for additional information
    *  regarding copyright ownership.  The ASF 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
    *
   *    http://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 org.apache.mina.transport.socket.apr;
  
  import java.io.IOException;
  import java.net.InetSocketAddress;
  import java.net.SocketAddress;
  import java.util.Iterator;
  import java.util.Queue;
  import java.util.concurrent.ConcurrentLinkedQueue;
  import java.util.concurrent.Executor;
  
  import org.apache.mina.core.RuntimeIoException;
  import org.apache.mina.core.polling.AbstractPollingIoAcceptor;
  import org.apache.mina.core.service.IoAcceptor;
  import org.apache.mina.core.service.IoProcessor;
  import org.apache.mina.core.service.IoService;
  import org.apache.mina.core.service.SimpleIoProcessorPool;
  import org.apache.mina.core.service.TransportMetadata;
  import org.apache.mina.transport.socket.DefaultSocketSessionConfig;
  import org.apache.tomcat.jni.Address;
  import org.apache.tomcat.jni.Poll;
  import org.apache.tomcat.jni.Pool;
  import org.apache.tomcat.jni.Socket;
  import org.apache.tomcat.jni.Status;
  
  /**
   * {@link IoAcceptor} for APR based socket transport (TCP/IP).
   *
   * @author <a href="http://mina.apache.org">Apache MINA Project</a>
   */
  public final class AprSocketAcceptor extends AbstractPollingIoAcceptor<AprSession, Long> {
      /** 
       * This constant is deduced from the APR code. It is used when the timeout
       * has expired while doing a poll() operation.
       */
      private static final int APR_TIMEUP_ERROR = -120001;
  
      private static final int POLLSET_SIZE = 1024;
  
      private final Object wakeupLock = new Object();
  
      private volatile long wakeupSocket;
  
      private volatile boolean toBeWakenUp;
  
      private volatile long pool;
  
      private volatile long pollset; // socket poller
  
      private final long[] polledSockets = new long[POLLSET_SIZE << 1];
  
      private final Queue<Long> polledHandles = new ConcurrentLinkedQueue<Long>();
  
      /**
       * Constructor for {@link AprSocketAcceptor} using default parameters (multiple thread model).
       */
      public AprSocketAcceptor() {
          super(new DefaultSocketSessionConfig(), AprIoProcessor.class);
          ((DefaultSocketSessionConfig) getSessionConfig()).init(this);
      }
  
      /**
       * Constructor for {@link AprSocketAcceptor} using default parameters, and 
       * given number of {@link AprIoProcessor} for multithreading I/O operations.
       * 
       * @param processorCount the number of processor to create and place in a
       * {@link SimpleIoProcessorPool} 
       */
      public AprSocketAcceptor(int processorCount) {
          super(new DefaultSocketSessionConfig(), AprIoProcessor.class, processorCount);
          ((DefaultSocketSessionConfig) getSessionConfig()).init(this);
      }
  
      /**
       *  Constructor for {@link AprSocketAcceptor} with default configuration but a
        *  specific {@link AprIoProcessor}, useful for sharing the same processor over multiple
        *  {@link IoService} of the same type.
        * @param processor the processor to use for managing I/O events
        */
      public AprSocketAcceptor(IoProcessor<AprSession> processor) {
          super(new DefaultSocketSessionConfig(), processor);
         ((DefaultSocketSessionConfig) getSessionConfig()).init(this);
     }
 
     /**
      *  Constructor for {@link AprSocketAcceptor} with a given {@link Executor} for handling 
      *  connection events and a given {@link AprIoProcessor} for handling I/O events, useful for 
      *  sharing the same processor and executor over multiple {@link IoService} of the same type.
      * @param executor the executor for connection
      * @param processor the processor for I/O operations
      */
     public AprSocketAcceptor(Executor executor, IoProcessor<AprSession> processor) {
         super(new DefaultSocketSessionConfig(), executor, processor);
         ((DefaultSocketSessionConfig) getSessionConfig()).init(this);
     }
 
     /**
      * {@inheritDoc}
      */
     @Override
     protected AprSession accept(IoProcessor<AprSession> processor, Long handle) throws Exception {
         long s = Socket.accept(handle);
         boolean success = false;
         try {
             AprSession result = new AprSocketSession(this, processor, s);
             success = true;
             return result;
         } finally {
             if (!success) {
                 Socket.close(s);
             }
         }
     }
 
     /**
      * {@inheritDoc}
      */
     @Override
     protected Long open(SocketAddress localAddress) throws Exception {
         InetSocketAddress la = (InetSocketAddress) localAddress;
         long handle = Socket.create(Socket.APR_INET, Socket.SOCK_STREAM, Socket.APR_PROTO_TCP, pool);
 
         boolean success = false;
         try {
             int result = Socket.optSet(handle, Socket.APR_SO_NONBLOCK, 1);
             if (result != Status.APR_SUCCESS) {
                 throwException(result);
             }
             result = Socket.timeoutSet(handle, 0);
             if (result != Status.APR_SUCCESS) {
                 throwException(result);
             }
 
             // Configure the server socket,
             result = Socket.optSet(handle, Socket.APR_SO_REUSEADDR, isReuseAddress() ? 1 : 0);
             if (result != Status.APR_SUCCESS) {
                 throwException(result);
             }
             result = Socket.optSet(handle, Socket.APR_SO_RCVBUF, getSessionConfig().getReceiveBufferSize());
             if (result != Status.APR_SUCCESS) {
                 throwException(result);
             }
 
             // and bind.
             long sa;
             if (la != null) {
                 if (la.getAddress() == null) {
                     sa = Address.info(Address.APR_ANYADDR, Socket.APR_INET, la.getPort(), 0, pool);
                 } else {
                     sa = Address.info(la.getAddress().getHostAddress(), Socket.APR_INET, la.getPort(), 0, pool);
                 }
             } else {
                 sa = Address.info(Address.APR_ANYADDR, Socket.APR_INET, 0, 0, pool);
             }
 
             result = Socket.bind(handle, sa);
             if (result != Status.APR_SUCCESS) {
                 throwException(result);
             }
             result = Socket.listen(handle, getBacklog());
             if (result != Status.APR_SUCCESS) {
                 throwException(result);
             }
 
             result = Poll.add(pollset, handle, Poll.APR_POLLIN);
             if (result != Status.APR_SUCCESS) {
                 throwException(result);
             }
             success = true;
         } finally {
             if (!success) {
                 close(handle);
             }
         }
         return handle;
     }
 
     /**
      * {@inheritDoc}
      */
     @Override
     protected void init() throws Exception {
         // initialize a memory pool for APR functions
         pool = Pool.create(AprLibrary.getInstance().getRootPool());
 
         wakeupSocket = Socket.create(Socket.APR_INET, Socket.SOCK_DGRAM, Socket.APR_PROTO_UDP, pool);
 
         pollset = Poll.create(POLLSET_SIZE, pool, Poll.APR_POLLSET_THREADSAFE, Long.MAX_VALUE);
 
         if (pollset <= 0) {
             pollset = Poll.create(62, pool, Poll.APR_POLLSET_THREADSAFE, Long.MAX_VALUE);
         }
 
         if (pollset <= 0) {
             if (Status.APR_STATUS_IS_ENOTIMPL(-(int) pollset)) {
                 throw new RuntimeIoException("Thread-safe pollset is not supported in this platform.");
             }
         }
     }
 
     /**
      * {@inheritDoc}
      */
     @Override
     protected void destroy() throws Exception {
         if (wakeupSocket > 0) {
             Socket.close(wakeupSocket);
         }
         if (pollset > 0) {
             Poll.destroy(pollset);
         }
         if (pool > 0) {
             Pool.destroy(pool);
         }
     }
 
     /**
      * {@inheritDoc}
      */
     @Override
     protected SocketAddress localAddress(Long handle) throws Exception {
         long la = Address.get(Socket.APR_LOCAL, handle);
         return new InetSocketAddress(Address.getip(la), Address.getInfo(la).port);
     }
 
     /**
      * {@inheritDoc}
      */
     @Override
     protected int select() throws Exception {
         int rv = Poll.poll(pollset, Integer.MAX_VALUE, polledSockets, false);
         if (rv <= 0) {
             // We have had an error. It can simply be that we have reached
             // the timeout (very unlikely, as we have set it to MAX_INTEGER)
             if (rv != APR_TIMEUP_ERROR) {
                 // It's not a timeout being exceeded. Throw the error
                 throwException(rv);
             }
 
             rv = Poll.maintain(pollset, polledSockets, true);
             if (rv > 0) {
                 for (int i = 0; i < rv; i++) {
                     Poll.add(pollset, polledSockets[i], Poll.APR_POLLIN);
                 }
             } else if (rv < 0) {
                 throwException(rv);
             }
 
             return 0;
         } else {
             rv <<= 1;
             if (!polledHandles.isEmpty()) {
                 polledHandles.clear();
             }
 
             for (int i = 0; i < rv; i++) {
                 long flag = polledSockets[i];
                 long socket = polledSockets[++i];
                 if (socket == wakeupSocket) {
                     synchronized (wakeupLock) {
                         Poll.remove(pollset, wakeupSocket);
                         toBeWakenUp = false;
                     }
                     continue;
                 }
 
                 if ((flag & Poll.APR_POLLIN) != 0) {
                     polledHandles.add(socket);
                 }
             }
             return polledHandles.size();
         }
     }
 
     /**
      * {@inheritDoc}
      */
     @Override
     protected Iterator<Long> selectedHandles() {
         return polledHandles.iterator();
     }
 
     /**
      * {@inheritDoc}
      */
     @Override
     protected void close(Long handle) throws Exception {
         Poll.remove(pollset, handle);
         int result = Socket.close(handle);
         if (result != Status.APR_SUCCESS) {
             throwException(result);
         }
     }
 
     /**
      * {@inheritDoc}
      */
     @Override
     protected void wakeup() {
         if (toBeWakenUp) {
             return;
         }
 
         // Add a dummy socket to the pollset.
         synchronized (wakeupLock) {
             toBeWakenUp = true;
             Poll.add(pollset, wakeupSocket, Poll.APR_POLLOUT);
         }
     }
 
     /**
      * {@inheritDoc}
      */
     @Override
     public InetSocketAddress getLocalAddress() {
         return (InetSocketAddress) super.getLocalAddress();
     }
 
     /**
      * {@inheritDoc}
      */
     @Override
     public InetSocketAddress getDefaultLocalAddress() {
         return (InetSocketAddress) super.getDefaultLocalAddress();
     }
 
     /**
      * {@inheritDoc}
      */
     public void setDefaultLocalAddress(InetSocketAddress localAddress) {
         super.setDefaultLocalAddress(localAddress);
     }
 
     /**
      * {@inheritDoc}
      */
     public TransportMetadata getTransportMetadata() {
         return AprSocketSession.METADATA;
     }
 
     /**
      * Convert an APR code into an Exception with the corresponding message
      * @param code error number
      * @throws IOException the generated exception
      */
     private void throwException(int code) throws IOException {
         throw new IOException(org.apache.tomcat.jni.Error.strerror(-code) + " (code: " + code + ")");
     }
 }