/*
    * 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.DefaultSelectStrategyFactory;
  import io.netty.channel.EventLoop;
  import io.netty.channel.EventLoopGroup;
  import io.netty.channel.EventLoopTaskQueueFactory;
  import io.netty.channel.MultithreadEventLoopGroup;
  import io.netty.channel.SelectStrategyFactory;
  import io.netty.channel.SingleThreadEventLoop;
  import io.netty.util.concurrent.EventExecutor;
  import io.netty.util.concurrent.EventExecutorChooserFactory;
  import io.netty.util.concurrent.RejectedExecutionHandler;
  import io.netty.util.concurrent.RejectedExecutionHandlers;
  
  import java.util.concurrent.Executor;
  import java.util.concurrent.ThreadFactory;
  
  /**
   * {@link EventLoopGroup} which uses epoll under the covers. Because of this
   * it only works on linux.
   */
  public final class EpollEventLoopGroup extends MultithreadEventLoopGroup {
  
      // This does not use static by design to ensure the class can be loaded and only do the check when its actually
      // instanced.
      {
          // Ensure JNI is initialized by the time this class is loaded.
          Epoll.ensureAvailability();
      }
  
      /**
       * Create a new instance using the default number of threads and the default {@link ThreadFactory}.
       */
      public EpollEventLoopGroup() {
          this(0);
      }
  
      /**
       * Create a new instance using the specified number of threads and the default {@link ThreadFactory}.
       */
      public EpollEventLoopGroup(int nThreads) {
          this(nThreads, (ThreadFactory) null);
      }
  
      /**
       * Create a new instance using the default number of threads and the given {@link ThreadFactory}.
       */
      @SuppressWarnings("deprecation")
      public EpollEventLoopGroup(ThreadFactory threadFactory) {
          this(0, threadFactory, 0);
      }
  
      /**
       * Create a new instance using the specified number of threads and the default {@link ThreadFactory}.
       */
      @SuppressWarnings("deprecation")
      public EpollEventLoopGroup(int nThreads, SelectStrategyFactory selectStrategyFactory) {
          this(nThreads, (ThreadFactory) null, selectStrategyFactory);
      }
  
      /**
       * Create a new instance using the specified number of threads and the given {@link ThreadFactory}.
       */
      @SuppressWarnings("deprecation")
      public EpollEventLoopGroup(int nThreads, ThreadFactory threadFactory) {
          this(nThreads, threadFactory, 0);
      }
  
      public EpollEventLoopGroup(int nThreads, Executor executor) {
          this(nThreads, executor, DefaultSelectStrategyFactory.INSTANCE);
      }
  
      /**
       * Create a new instance using the specified number of threads and the given {@link ThreadFactory}.
       */
      @SuppressWarnings("deprecation")
      public EpollEventLoopGroup(int nThreads, ThreadFactory threadFactory, SelectStrategyFactory selectStrategyFactory) {
          this(nThreads, threadFactory, 0, selectStrategyFactory);
      }
  
      /**
       * Create a new instance using the specified number of threads, the given {@link ThreadFactory} and the given
       * maximal amount of epoll events to handle per epollWait(...).
       *
      * @deprecated  Use {@link #EpollEventLoopGroup(int)} or {@link #EpollEventLoopGroup(int, ThreadFactory)}
      */
     @Deprecated
     public EpollEventLoopGroup(int nThreads, ThreadFactory threadFactory, int maxEventsAtOnce) {
         this(nThreads, threadFactory, maxEventsAtOnce, DefaultSelectStrategyFactory.INSTANCE);
     }
 
     /**
      * Create a new instance using the specified number of threads, the given {@link ThreadFactory} and the given
      * maximal amount of epoll events to handle per epollWait(...).
      *
      * @deprecated  Use {@link #EpollEventLoopGroup(int)}, {@link #EpollEventLoopGroup(int, ThreadFactory)}, or
      * {@link #EpollEventLoopGroup(int, SelectStrategyFactory)}
      */
     @Deprecated
     public EpollEventLoopGroup(int nThreads, ThreadFactory threadFactory, int maxEventsAtOnce,
                                SelectStrategyFactory selectStrategyFactory) {
         super(nThreads, threadFactory, maxEventsAtOnce, selectStrategyFactory, RejectedExecutionHandlers.reject());
     }
 
     public EpollEventLoopGroup(int nThreads, Executor executor, SelectStrategyFactory selectStrategyFactory) {
         super(nThreads, executor, 0, selectStrategyFactory, RejectedExecutionHandlers.reject());
     }
 
     public EpollEventLoopGroup(int nThreads, Executor executor, EventExecutorChooserFactory chooserFactory,
                                SelectStrategyFactory selectStrategyFactory) {
         super(nThreads, executor, chooserFactory, 0, selectStrategyFactory, RejectedExecutionHandlers.reject());
     }
 
     public EpollEventLoopGroup(int nThreads, Executor executor, EventExecutorChooserFactory chooserFactory,
                                SelectStrategyFactory selectStrategyFactory,
                                RejectedExecutionHandler rejectedExecutionHandler) {
         super(nThreads, executor, chooserFactory, 0, selectStrategyFactory, rejectedExecutionHandler);
     }
 
     public EpollEventLoopGroup(int nThreads, Executor executor, EventExecutorChooserFactory chooserFactory,
                                SelectStrategyFactory selectStrategyFactory,
                                RejectedExecutionHandler rejectedExecutionHandler,
                                EventLoopTaskQueueFactory queueFactory) {
         super(nThreads, executor, chooserFactory, 0, selectStrategyFactory, rejectedExecutionHandler, queueFactory);
     }
 
     /**
      * @param nThreads the number of threads that will be used by this instance.
      * @param executor the Executor to use, or {@code null} if default one should be used.
      * @param chooserFactory the {@link EventExecutorChooserFactory} to use.
      * @param selectStrategyFactory the {@link SelectStrategyFactory} to use.
      * @param rejectedExecutionHandler the {@link RejectedExecutionHandler} to use.
      * @param taskQueueFactory the {@link EventLoopTaskQueueFactory} to use for
      *                         {@link SingleThreadEventLoop#execute(Runnable)},
      *                         or {@code null} if default one should be used.
      * @param tailTaskQueueFactory the {@link EventLoopTaskQueueFactory} to use for
      *                             {@link SingleThreadEventLoop#executeAfterEventLoopIteration(Runnable)},
      *                             or {@code null} if default one should be used.
      */
     public EpollEventLoopGroup(int nThreads, Executor executor, EventExecutorChooserFactory chooserFactory,
                                SelectStrategyFactory selectStrategyFactory,
                                RejectedExecutionHandler rejectedExecutionHandler,
                                EventLoopTaskQueueFactory taskQueueFactory,
                                EventLoopTaskQueueFactory tailTaskQueueFactory) {
         super(nThreads, executor, chooserFactory, 0, selectStrategyFactory, rejectedExecutionHandler, taskQueueFactory,
                 tailTaskQueueFactory);
     }
 
     /**
      * Sets the percentage of the desired amount of time spent for I/O in the child event loops.  The default value is
      * {@code 50}, which means the event loop will try to spend the same amount of time for I/O as for non-I/O tasks.
      */
     public void setIoRatio(int ioRatio) {
         for (EventExecutor e: this) {
             ((EpollEventLoop) e).setIoRatio(ioRatio);
         }
     }
 
     @Override
     protected EventLoop newChild(Executor executor, Object... args) throws Exception {
         Integer maxEvents = (Integer) args[0];
         SelectStrategyFactory selectStrategyFactory = (SelectStrategyFactory) args[1];
         RejectedExecutionHandler rejectedExecutionHandler = (RejectedExecutionHandler) args[2];
         EventLoopTaskQueueFactory taskQueueFactory = null;
         EventLoopTaskQueueFactory tailTaskQueueFactory = null;
 
         int argsLength = args.length;
         if (argsLength > 3) {
             taskQueueFactory = (EventLoopTaskQueueFactory) args[3];
         }
         if (argsLength > 4) {
             tailTaskQueueFactory = (EventLoopTaskQueueFactory) args[4];
         }
         return new EpollEventLoop(this, executor, maxEvents,
                 selectStrategyFactory.newSelectStrategy(),
                 rejectedExecutionHandler, taskQueueFactory, tailTaskQueueFactory);
     }
 }