Source: ../../libxorp/timer.hh
|
|
|
|
// -*- c-basic-offset: 4; tab-width: 8; indent-tabs-mode: t -*-
// vim:set sts=4 ts=8:
// Copyright (c) 2001-2009 XORP, Inc.
//
// This program is free software; you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License, Version
// 2.1, June 1999 as published by the Free Software Foundation.
// Redistribution and/or modification of this program under the terms of
// any other version of the GNU Lesser General Public License is not
// permitted.
//
// 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. For more details,
// see the GNU Lesser General Public License, Version 2.1, a copy of
// which can be found in the XORP LICENSE.lgpl file.
//
// XORP, Inc, 2953 Bunker Hill Lane, Suite 204, Santa Clara, CA 95054, USA;
// http://xorp.net
// $XORP: xorp/libxorp/timer.hh,v 1.41 2009/01/05 18:30:58 jtc Exp $
#ifndef __LIBXORP_TIMER_HH__
#define __LIBXORP_TIMER_HH__
#include <assert.h>
#include <memory>
#include <list>
#include <map>
#ifdef HAVE_SYS_TIME_H
#include <sys/time.h>
#endif
#include "timeval.hh"
#include "heap.hh"
#include "callback.hh"
#include "task.hh"
class XorpTimer;
class TimerNode;
class TimerList;
class ClockBase;
typedef XorpCallback0<void>::RefPtr OneoffTimerCallback;
// PeriodicTimerCallback methods should return true to reschedule
typedef XorpCallback0<bool>::RefPtr PeriodicTimerCallback;
typedef XorpCallback1<void, XorpTimer&>::RefPtr BasicTimerCallback;
/**
* @short Abstract class used to receive TimerList notifications
*
* TimerListObserverBase is a class that can be subtyped to receive
* notifications on when timers are created or expired. All the methods in
* this class are private, since they must only be invoked by the friend class,
* TimerList
*
* @see TimerList
*/
class TimerListObserverBase {
public:
virtual ~TimerListObserverBase();
private:
/**
* This function will get called when a timer is scheduled. Periodic
* timers will produce periodic notifications.
*/
virtual void notify_scheduled(const TimeVal&) = 0;
/**
* This function will get called when a timer is unscheduled.
*/
virtual void notify_unscheduled(const TimeVal&) = 0;
TimerList * _observed;
friend class TimerList;
};
/**
* @short XorpTimer class
*
* Timers allow callbacks to be made at a specific time in the future.
* They are ordinarily created via TimerList methods, and they
* must be associated with an TimerList object in order to be
* runnable.
*
* @see TimerList
*/
class XorpTimer {
public:
/**
* @return true if the timer has been scheduled, and the callback
* associated with this timer has not been called yet.
*/
bool scheduled() const;
/**
* @return the expiry time of the @ref XorpTimer
*/
const TimeVal& expiry() const;
/**
* Get the remaining time until the timer expires.
*
* @param remain the return-by-reference value with the remaining
* time until the timer expires. If the current time is beyond
* the expire time (e.g., if we are behind schedule with the timer
* processing), the return time is zero.
* @return true if the remaining time has meaningful value (e.g.,
* if timer was scheduled), otherwise false.
*/
bool time_remaining(TimeVal& remain) const;
/**
* Expire the @ref XorpTimer object when the TimerList is next run.
*/
void schedule_now(int priority = XorpTask::PRIORITY_DEFAULT);
/**
* Schedule the @ref XorpTimer object at a given time.
*/
void schedule_at(const TimeVal& when,
int priority = XorpTask::PRIORITY_DEFAULT);
/**
* Schedule the @ref XorpTimer object to expire in @ref wait
* after the current time.
*/
void schedule_after(const TimeVal& wait,
int priority = XorpTask::PRIORITY_DEFAULT);
/**
* Schedule the @ref XorpTimer object.
*
* @param ms milliseconds from the current time.
*/
void schedule_after_ms(int ms,
int priority = XorpTask::PRIORITY_DEFAULT);
/**
* Reschedule the @ref XorpTimer object.
*
* @param wait time from the most recent expiry.
*/
void reschedule_after(const TimeVal& wait);
/**
* Reschedule the @ref XorpTimer object.
*
* @param ms milliseconds from the most recent expiry.
*/
void reschedule_after_ms(int ms);
/**
* Unschedule the @ref XorpTimer object. The XorpTimer callback is not
* invoked.
*/
void unschedule(); // unschedule if scheduled
/**
* Release reference to underlying state.
*/
void clear(); // erase timer
XorpTimer() : _node(0) { }
XorpTimer(TimerList* list, BasicTimerCallback cb);
XorpTimer(const XorpTimer&);
~XorpTimer();
XorpTimer& operator=(const XorpTimer&);
TimerNode* node() const { return _node; }
private:
TimerNode* _node;
XorpTimer(TimerNode* n);
friend class TimerList;
};
/**
* @short XorpTimer creation and scheduling entity
*
* A TimerList is a scheduling entity that provides a means to
* create @ref XorpTimer objects and run them.
*
* XorpTimer objects created via TimerList methods contain pointers to
* reference counted elements maintained in the TimerList. The
* elements on the list need to be referenced by XorpTimer objects or
* the underlying timer callbacks are never made. For instance:
*
<pre>
TimerList timer_list;
XorpTimer t = timer_list.new_oneoff_after(TimeVal(0, 100000),
callback(some_function, some_arg));
new_oneoff_after(TimeVal(0, 200000), my_callback_b, my_parameter_a);
while ( ! timer_list.empty() ) {
timer_list.run();
}
</pre>
*
* <code>my_callback_a</code> is called 100000us after the @ref XorpTimer
* object is created.
* <code>my_callback_b</code> is never called
* because no XorpTimer references the underlying element on the TimerList
* after <code>TimerList::new_oneoff_after()</code> is called.
*/
class TimerList {
public:
/**
* @param clock clock object to use to query time.
*/
TimerList(ClockBase* clock);
~TimerList();
/**
* Expire all pending @ref XorpTimer objects associated with @ref
* TimerList.
*/
void run();
/**
* Create a XorpTimer that will be scheduled once.
*
* @param when the absolute time when the timer expires.
* @param ocb callback object that is invoked when timer expires.
*
* @return the @ref XorpTimer created.
*/
XorpTimer new_oneoff_at(const TimeVal& when,
const OneoffTimerCallback& ocb,
int priority = XorpTask::PRIORITY_DEFAULT);
/**
* Create a XorpTimer that will be scheduled once.
*
* @param wait the relative time when the timer expires.
* @param ocb callback object that is invoked when timer expires.
*
* @return the @ref XorpTimer created.
*/
XorpTimer new_oneoff_after(const TimeVal& wait,
const OneoffTimerCallback& ocb,
int priority = XorpTask::PRIORITY_DEFAULT);
/**
* Create a XorpTimer that will invoke a callback periodically.
*
* @param wait the period when the timer expires.
* @param pcb user callback object that is invoked when timer expires.
* If the callback returns false the periodic XorpTimer is unscheduled.
*
* @return the @ref XorpTimer created.
*/
XorpTimer new_periodic(const TimeVal& wait,
const PeriodicTimerCallback& pcb,
int priority = XorpTask::PRIORITY_DEFAULT);
/**
* Create a XorpTimer to set a flag.
*
* @param when the absolute time when the timer expires.
*
* @param flag_ptr pointer to a boolean variable that is set to
* @ref to_value when the @ref XorpTimer expires.
*
* @return the @ref XorpTimer created.
*/
XorpTimer set_flag_at(const TimeVal& when,
bool* flag_ptr,
bool to_value = true,
int priority = XorpTask::PRIORITY_DEFAULT);
/**
* Create a XorpTimer to set a flag.
*
* @param wait the relative time when the timer expires.
*
* @param flag_ptr pointer to a boolean variable that is set to
* @ref to_value when the @ref XorpTimer expires.
*
* @return the @ref XorpTimer created.
*/
XorpTimer set_flag_after(const TimeVal& wait,
bool* flag_ptr,
bool to_value = true,
int priority = XorpTask::PRIORITY_DEFAULT);
/**
* Custom XorpTimer creation method. The @ref XorpTimer object created
* needs to be explicitly scheduled with the available @ref XorpTimer
* methods.
*
* @param hook user function to be invoked when XorpTimer expires.
*
* @param thunk user argument to be passed when user's function is
* invoked.
*
* @return the @ref XorpTimer created.
*/
XorpTimer new_timer(const BasicTimerCallback& cb) {
return XorpTimer(this, cb);
}
/**
* @return true if there no @ref XorpTimer objects currently scheduled on
* list.
*/
bool empty() const;
/**
* @return the number of scheduled objects.
*/
size_t size() const;
/**
* Query the next XorpTimer Expiry time.
*
* @param tv reference that is assigned expiry time of next timer.
* If there is no @ref XorpTimer pending, this value is assigned the
* maximum @ref TimeVal::MAXIMUM(). The first function returns the
* absolute time at which the timer expires, where the second returns the
* difference between now and the expiry time.
*
* @return true if there is a XorpTimer awaiting expiry, false otherwise.
*/
bool get_next_delay(TimeVal& tv) const;
/**
* Get the priority of the highest priority timer that has expired.
*
* @return the priority of the expired timer, or INFINITE_PRIORITY
* if no timer has expired.
*/
int get_expired_priority() const;
/**
* Read the latest known value from the clock used by @ref
* TimerList object.
*
* @param now the return-by-reference value with the current time.
*/
void current_time(TimeVal& now) const;
/**
* Advance time. This method fetches the time from clock object
* associated with the TimerList and sets the TimerList current
* time to this value.
*/
void advance_time();
/**
* Default time querier.
*
* Get the current time. This method is analogous to calling
* the underlying operating system's 'get current system time'
* function and is implemented as a call to advance_time()
* followed by a call to current_time().
*
* @param tv a pointer to the @ref TimeVal storage to store the current
* time.
*/
static void system_gettimeofday(TimeVal* tv);
/**
* Suspend process execution for a defined interval.
*
* This methid is analogous to calling sleep(3) or usleep(3),
* and is implemented as a call to sleep(3) and/or usleep(3)
* followed by a call to advance_time().
*
* @param tv the period of time to suspend execution.
*/
static void system_sleep(const TimeVal& tv);
/**
* Register an observer object with this class
*
* @param obs an observer object derived from @ref TimerListObserverBase
*/
void set_observer(TimerListObserverBase& obs);
/**
* Unregister the current observer
*/
void remove_observer();
/**
* Get pointer to sole TimerList instance.
*
* @return pointer if TimerList has been constructed, NULL otherwise.
*/
static TimerList* instance();
private:
void schedule_node(TimerNode* t); // insert in time ordered pos.
void unschedule_node(TimerNode* t); // remove from list
void acquire_lock() const { /* nothing, for now */ }
bool attempt_lock() const { return true; }
void release_lock() const { /* nothing, for now */ }
// find or create the heap assoicated with this priority level
Heap* find_heap(int priority);
// expire the highest priority timer
bool expire_one(int worst_priority);
private:
TimerList(const TimerList&); // not implemented
TimerList& operator=(const TimerList&); // not implemented
private:
// we need one heap for each priority level
map<int, Heap*> _heaplist;
ClockBase* _clock;
TimerListObserverBase* _observer;
#ifdef HOST_OS_WINDOWS
HANDLE _hirestimer;
#endif
friend class TimerNode;
friend class TimerListObserverBase;
};
class TimerNode : public HeapBase {
protected:
TimerNode(TimerList*, BasicTimerCallback);
virtual ~TimerNode();
void add_ref();
void release_ref();
// we want this even if it is never called, to override the
// default supplied by the compiler.
TimerNode(const TimerNode&); // never called
TimerNode& operator=(const TimerNode&);
bool scheduled() const { return _pos_in_heap >= 0; }
int priority() const { return _priority; }
const TimeVal& expiry() const { return _expires; }
bool time_remaining(TimeVal& remain) const;
void schedule_at(const TimeVal&, int priority);
void schedule_after(const TimeVal& wait, int priority);
void reschedule_after(const TimeVal& wait);
void unschedule();
virtual void expire(XorpTimer&, void*);
int _ref_cnt; // Number of referring XorpTimer objects
TimeVal _expires; // Expiration time
BasicTimerCallback _cb;
int _priority; // Scheduling priority
TimerList* _list; // TimerList this node is associated w.
friend class XorpTimer;
friend class TimerList;
};
// ----------------------------------------------------------------------------
// inline Timer methods
inline XorpTimer::XorpTimer(TimerNode* n)
: _node(n)
{
if (_node)
_node->add_ref();
}
inline XorpTimer::XorpTimer(TimerList* tlist, BasicTimerCallback cb)
: _node(new TimerNode(tlist, cb))
{
if (_node)
_node->add_ref();
}
inline XorpTimer::XorpTimer(const XorpTimer& t)
: _node(t._node)
{
if (_node)
_node->add_ref();
}
inline XorpTimer::~XorpTimer()
{
if (_node)
_node->release_ref();
}
inline XorpTimer&
XorpTimer::operator=(const XorpTimer& t)
{
if (t._node)
t._node->add_ref();
if (_node)
_node->release_ref();
_node = t._node;
return *this;
}
inline bool
XorpTimer::scheduled() const
{
return _node && _node->scheduled();
}
inline const TimeVal&
XorpTimer::expiry() const
{
assert(_node);
return _node->expiry();
}
inline bool
XorpTimer::time_remaining(TimeVal& remain) const
{
if (_node == NULL) {
remain = TimeVal::ZERO();
return (false);
}
return (_node->time_remaining(remain));
}
inline void
XorpTimer::schedule_at(const TimeVal& t, int priority)
{
assert(_node);
_node->schedule_at(t, priority);
}
inline void
XorpTimer::schedule_after(const TimeVal& wait, int priority)
{
assert(_node);
_node->schedule_after(wait, priority);
}
inline void
XorpTimer::schedule_after_ms(int ms, int priority)
{
assert(_node);
TimeVal wait(ms / 1000, (ms % 1000) * 1000);
_node->schedule_after(wait, priority);
}
inline void
XorpTimer::schedule_now(int priority)
{
schedule_after(TimeVal::ZERO(), priority);
}
inline void
XorpTimer::reschedule_after(const TimeVal& wait)
{
assert(_node);
_node->reschedule_after(wait);
}
inline void
XorpTimer::reschedule_after_ms(int ms)
{
assert(_node);
TimeVal wait(ms / 1000, (ms % 1000) * 1000);
_node->reschedule_after(wait);
}
inline void
XorpTimer::unschedule()
{
if (_node)
_node->unschedule();
}
inline void
XorpTimer::clear()
{
if (_node)
_node->release_ref();
_node = 0;
}
#endif // __LIBXORP_TIMER_HH__
Generated by: pavlin on kobe.xorp.net on Wed Jan 7 19:10:36 2009, using kdoc 2.0a54+XORP.
