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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 "Cond.h"
#include "Mutex.h"
#include <map>
class CephContext;
class Context;
class SafeTimerThread;
class SafeTimer
{
// This class isn't supposed to be copied
SafeTimer(const SafeTimer &rhs);
SafeTimer& operator=(const SafeTimer &rhs);
CephContext *cct;
Mutex& lock;
Cond cond;
bool safe_callbacks;
friend class SafeTimerThread;
SafeTimerThread *thread;
void timer_thread();
void _shutdown();
std::multimap<utime_t, Context*> schedule;
std::map<Context*, std::multimap<utime_t, Context*>::iterator> events;
bool stopping;
void dump(const char *caller = 0) const;
public:
/* 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.
* */
SafeTimer(CephContext *cct, Mutex &l, bool safe_callbacks=true);
~SafeTimer();
/* 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 */
void add_event_after(double seconds, Context *callback);
void add_event_at(utime_t when, Context *callback);
/* Cancel an event.
* Call with the event_lock LOCKED
*
* Returns true if the callback was cancelled.
* Returns false if you never addded 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();
};
#endif
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