EPoller.h

/*
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 *
 * EPoller.h
 * A Poller which uses epoll()
 * Copyright (C) 2013 Simon Newton
 */

#ifndef COMMON_IO_EPOLLER_H_
#define COMMON_IO_EPOLLER_H_

#include <ola/base/Macro.h>
#include <ola/Clock.h>
#include <ola/ExportMap.h>
#include <ola/io/Descriptor.h>
#include <sys/epoll.h>

#include <map>
#include <set>
#include <string>
#include <utility>
#include <vector>

#include "common/io/PollerInterface.h"
#include "common/io/TimeoutManager.h"

namespace ola {
namespace io {

class EPollData;

class EPoller : public PollerInterface {
 public :
 EPoller(ExportMap *export_map, Clock *clock);

 ~EPoller();

 bool AddReadDescriptor(class ReadFileDescriptor *descriptor);
 bool AddReadDescriptor(class ConnectedDescriptor *descriptor,
 bool delete_on_close);
 bool RemoveReadDescriptor(class ReadFileDescriptor *descriptor);
 bool RemoveReadDescriptor(class ConnectedDescriptor *descriptor);

 bool AddWriteDescriptor(class WriteFileDescriptor *descriptor);
 bool RemoveWriteDescriptor(class WriteFileDescriptor *descriptor);

 const TimeStamp *WakeUpTime() const { return &m_wake_up_time; }

 bool Poll(TimeoutManager *timeout_manager,
 const TimeInterval &poll_interval);

 private:
 typedef std::map<int, EPollData*> DescriptorMap;
 typedef std::vector<EPollData*> DescriptorList;

 DescriptorMap m_descriptor_map;

 // EPoller is re-enterant. Remove may be called while we hold a pointer to an
 // EPollData. To avoid deleting data out from underneath ourselves, we
 // instead move the removed descriptors to this list and then clean them up
 // outside the callback loop.
 DescriptorList m_orphaned_descriptors;
 // A list of pre-allocated descriptors we can use.
 DescriptorList m_free_descriptors;
 ExportMap *m_export_map;
 CounterVariable *m_loop_iterations;
 CounterVariable *m_loop_time;
 int m_epoll_fd;
 Clock *m_clock;
 TimeStamp m_wake_up_time;

 std::pair<EPollData*, bool> LookupOrCreateDescriptor(int fd);

 bool RemoveDescriptor(int fd, int event, bool warn_on_missing);
 void CheckDescriptor(struct epoll_event *event, EPollData *descriptor);

 static const int MAX_EVENTS;
 static const int READ_FLAGS;
 static const unsigned int MAX_FREE_DESCRIPTORS;

 DISALLOW_COPY_AND_ASSIGN(EPoller);
};
} // namespace io
} // namespace ola
#endif // COMMON_IO_EPOLLER_H_