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// -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
// vim: ts=8 sw=2 smarttab
/*
* Ceph - scalable distributed file system
*
* Copyright (C) 2004-2006 Sage Weil <sage@newdream.net>
*
* This is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License version 2.1, as published by the Free Software
* Foundation. See file COPYING.
*
*/
#ifndef CEPH_TIMER_H
#define CEPH_TIMER_H
#include <map>
#include "include/common_fwd.h"
#include "ceph_time.h"
#include "ceph_mutex.h"
#include "fair_mutex.h"
#include <condition_variable>
class Context;
template <class Mutex> class CommonSafeTimerThread;
template <class Mutex>
class CommonSafeTimer
{
CephContext *cct;
Mutex& lock;
std::condition_variable_any cond;
bool safe_callbacks;
friend class CommonSafeTimerThread<Mutex>;
class CommonSafeTimerThread<Mutex> *thread;
void timer_thread();
void _shutdown();
using clock_t = ceph::real_clock;
using scheduled_map_t = std::multimap<clock_t::time_point, Context*>;
scheduled_map_t schedule;
using event_lookup_map_t = std::map<Context*, scheduled_map_t::iterator>;
event_lookup_map_t events;
bool stopping;
void dump(const char *caller = 0) const;
public:
// This class isn't supposed to be copied
CommonSafeTimer(const CommonSafeTimer&) = delete;
CommonSafeTimer& operator=(const CommonSafeTimer&) = delete;
/* Safe callbacks determines whether callbacks are called with the lock
* held.
*
* safe_callbacks = true (default option) guarantees that a cancelled
* event's callback will never be called.
*
* Under some circumstances, holding the lock can cause lock cycles.
* If you are able to relax requirements on cancelled callbacks, then
* setting safe_callbacks = false eliminates the lock cycle issue.
* */
CommonSafeTimer(CephContext *cct, Mutex &l, bool safe_callbacks=true);
virtual ~CommonSafeTimer();
/* Call with the event_lock UNLOCKED.
*
* Cancel all events and stop the timer thread.
*
* If there are any events that still have to run, they will need to take
* the event_lock first. */
void init();
void shutdown();
/* Schedule an event in the future
* Call with the event_lock LOCKED */
Context* add_event_after(ceph::timespan duration, Context *callback);
Context* add_event_after(double seconds, Context *callback);
Context* add_event_at(clock_t::time_point when, Context *callback);
/* Cancel an event.
* Call with the event_lock LOCKED
*
* Returns true if the callback was cancelled.
* Returns false if you never added the callback in the first place.
*/
bool cancel_event(Context *callback);
/* Cancel all events.
* Call with the event_lock LOCKED
*
* When this function returns, all events have been cancelled, and there are no
* more in progress.
*/
void cancel_all_events();
};
extern template class CommonSafeTimer<ceph::mutex>;
extern template class CommonSafeTimer<ceph::fair_mutex>;
using SafeTimer = class CommonSafeTimer<ceph::mutex>;
#endif
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