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unison/src/core/model/timer.h
2021-08-23 19:52:57 +00:00

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/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
/*
* Copyright (c) 2007 INRIA
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation;
*
* This program 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
* Author: Mathieu Lacage <mathieu.lacage@sophia.inria.fr>
*/
#ifndef TIMER_H
#define TIMER_H
#include "fatal-error.h"
#include "nstime.h"
#include "event-id.h"
#include "int-to-type.h"
/**
* \file
* \ingroup timer
* ns3::Timer class declaration.
*/
namespace ns3 {
/**
* \ingroup core
* \defgroup timer Virtual Time Timer and Watchdog
*
* The Timer and Watchdog objects both facilitate scheduling functions
* to execute a specified virtual time in the future.
*
* A Watchdog timer cannot be paused or cancelled once it has been started,
* however it can be lengthened (delayed). A Watchdog takes no action
* when it is destroyed.
*
* A Timer can be suspended, resumed, cancelled and queried for time left,
* but it can't be extended (except by suspending and resuming).
* In addition, it can be configured to take different actions when the
* Timer is destroyed.
*/
class TimerImpl;
/**
* \ingroup timer
* \brief A simple virtual Timer class
*
* A (virtual time) timer is used to hold together a delay, a function to invoke
* when the delay expires, and a set of arguments to pass to the function
* when the delay expires.
*
* A Timer can be suspended, resumed, cancelled and queried for the
* time left, but it can't be extended (except by suspending and
* resuming).
*
* A timer can also be used to enforce a set of predefined event lifetime
* management policies. These policies are specified at construction time
* and cannot be changed after.
*
* \see Watchdog for a simpler interface for a watchdog timer.
*/
class Timer
{
public:
/**
* The policy to use to manager the internal timer when an
* instance of the Timer class is destroyed or suspended.
*
* In the case of suspension, only `CANCEL_ON_DESTROY` and
* `REMOVE_ON_DESTROY` apply.
*
* These symbols have "Destroy" in their names
* for historical reasons.
*/
enum DestroyPolicy
{
/**
* This policy cancels the event from the destructor of the Timer
* or from Suspend(). This is typically faster than `REMOVE_ON_DESTROY`
* but uses more memory.
*/
CANCEL_ON_DESTROY = (1 << 3),
/**
* This policy removes the event from the simulation event list
* when the destructor of the Timer is invoked, or the Timer is
* suspended. This is typically slower than Cancel, but frees memory.
*/
REMOVE_ON_DESTROY = (1 << 4),
/**
* This policy enforces a check from the destructor of the Timer
* to verify that the timer has already expired.
*/
CHECK_ON_DESTROY = (1 << 5)
};
/** The possible states of the Timer. */
enum State
{
RUNNING, /**< Timer is currently running. */
EXPIRED, /**< Timer has already expired. */
SUSPENDED, /**< Timer is suspended. */
};
/**
* Create a timer with a default event lifetime management policy:
* - CHECK_ON_DESTROY
*/
Timer ();
/**
* \param [in] destroyPolicy the event lifetime management policies
* to use for destroy events
*/
Timer (enum DestroyPolicy destroyPolicy);
~Timer ();
/**
* \tparam FN \deduced The type of the function.
* \param [in] fn the function
*
* Store this function in this Timer for later use by Timer::Schedule.
*/
template <typename FN>
void SetFunction (FN fn);
/**
* \tparam MEM_PTR \deduced The type of the class member function.
* \tparam OBJ_PTR \deduced The type of the class instance pointer.
* \param [in] memPtr the member function pointer
* \param [in] objPtr the pointer to object
*
* Store this function and object in this Timer for later use by
* Timer::Schedule.
*/
template <typename MEM_PTR, typename OBJ_PTR>
void SetFunction (MEM_PTR memPtr, OBJ_PTR objPtr);
/**
* \tparam Ts \deduced Argument types
* \param [in] args arguments
*
* Store these arguments in this Timer for later use by Timer::Schedule.
*/
template <typename... Ts>
void SetArguments (Ts... args);
/**
* \param [in] delay The delay
*
* The next call to Schedule will schedule the timer with this delay.
*/
void SetDelay (const Time &delay);
/**
* \returns The currently-configured delay for the next Schedule.
*/
Time GetDelay (void) const;
/**
* \returns The amount of time left until this timer expires.
*
* This method returns zero if the timer is in EXPIRED state.
*/
Time GetDelayLeft (void) const;
/**
* Cancel the currently-running event if there is one. Do nothing
* otherwise.
*/
void Cancel (void);
/**
* Remove from the simulation event-list the currently-running event
* if there is one. Do nothing otherwise.
*/
void Remove (void);
/**
* \return \c true if there is no currently-running event,
* \c false otherwise.
*/
bool IsExpired (void) const;
/**
* \return \c true if there is a currently-running event,
* \c false otherwise.
*/
bool IsRunning (void) const;
/**
* \returns \c true if this timer was suspended and not yet resumed,
* \c false otherwise.
*/
bool IsSuspended (void) const;
/**
* \returns The current state of the timer.
*/
enum Timer::State GetState (void) const;
/**
* Schedule a new event using the currently-configured delay, function,
* and arguments.
*/
void Schedule (void);
/**
* \param [in] delay the delay to use
*
* Schedule a new event using the specified delay (ignore the delay set by
* Timer::SetDelay), function, and arguments.
*/
void Schedule (Time delay);
/**
* Pause the timer and save the amount of time left until it was
* set to expire.
*
* Subsequently calling Resume() will restart the Timer with the
* remaining time.
*
* The DestroyPolicy set at construction determines
* whether the underlying Simulator::Event is cancelled or removed.
*
* Calling Suspend on a non-running timer is an error.
*/
void Suspend (void);
/**
* Restart the timer to expire within the amount of time left saved
* during Suspend.
* Calling Resume without a prior call to Suspend is an error.
*/
void Resume (void);
private:
/** Internal bit marking the suspended state. */
enum InternalSuspended
{
TIMER_SUSPENDED = (1 << 7) /** Timer suspended. */
};
/**
* Bitfield for Timer State, DestroyPolicy and InternalSuspended.
*
* \internal
* The DestroyPolicy, State and InternalSuspended state are stored
* in this single bitfield. The State uses the low-order bits,
* so the other users of the bitfield have to be careful in defining
* their bits to avoid the State.
*/
int m_flags;
/** The delay configured for this Timer. */
Time m_delay;
/** The future event scheduled to expire the timer. */
EventId m_event;
/**
* The timer implementation, which contains the bound callback
* function and arguments.
*/
TimerImpl *m_impl;
/** The amount of time left on the Timer while it is suspended. */
Time m_delayLeft;
};
} // namespace ns3
/********************************************************************
* Implementation of the templates declared above.
********************************************************************/
#include "timer-impl.h"
namespace ns3 {
template <typename FN>
void
Timer::SetFunction (FN fn)
{
delete m_impl;
m_impl = MakeTimerImpl (fn);
}
template <typename MEM_PTR, typename OBJ_PTR>
void
Timer::SetFunction (MEM_PTR memPtr, OBJ_PTR objPtr)
{
delete m_impl;
m_impl = MakeTimerImpl (memPtr, objPtr);
}
template <typename... Ts>
void
Timer::SetArguments (Ts... args)
{
if (m_impl == 0)
{
NS_FATAL_ERROR ("You cannot set the arguments of a Timer before setting its function.");
return;
}
m_impl->SetArgs (args...);
}
} // namespace ns3
#endif /* TIMER_H */