// excerpts from http://code.google.com/p/muduo/
//
// Use of this source code is governed by a BSD-style license
// that can be found in the License file.
//
// Author: Shuo Chen (chenshuo at chenshuo dot com)

#ifndef MUDUO_NET_EPOLLER_H
#define MUDUO_NET_EPOLLER_H

#include <map>
#include <vector>

#include "datetime/Timestamp.h"
#include "EventLoop.h"

struct epoll_event;

namespace muduo
{

class Channel;

///
/// IO Multiplexing with epoll(4).
///
/// This class doesn't own the Channel objects.
class EPoller : boost::noncopyable
{
 public:
  typedef std::vector<Channel*> ChannelList;

  EPoller(EventLoop* loop);
  ~EPoller();

  /// Polls the I/O events.
  /// Must be called in the loop thread.
  Timestamp poll(int timeoutMs, ChannelList* activeChannels);

  /// Changes the interested I/O events.
  /// Must be called in the loop thread.
  void updateChannel(Channel* channel);
  /// Remove the channel, when it destructs.
  /// Must be called in the loop thread.
  void removeChannel(Channel* channel);

  void assertInLoopThread() { ownerLoop_->assertInLoopThread(); }

 private:
  static const int kInitEventListSize = 16;

  void fillActiveChannels(int numEvents,
                          ChannelList* activeChannels) const;
  void update(int operation, Channel* channel);

  typedef std::vector<struct epoll_event> EventList;
  typedef std::map<int, Channel*> ChannelMap;

  EventLoop* ownerLoop_;
  int epollfd_;
  EventList events_;
  ChannelMap channels_;
};

}
#endif  // MUDUO_NET_EPOLLER_H