Source: ../../libxorp/eventloop.hh
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// -*- c-basic-offset: 4; tab-width: 8; indent-tabs-mode: t -*-
// Copyright (c) 2001-2004 International Computer Science Institute
//
// Permission is hereby granted, free of charge, to any person obtaining a
// copy of this software and associated documentation files (the "Software")
// to deal in the Software without restriction, subject to the conditions
// listed in the XORP LICENSE file. These conditions include: you must
// preserve this copyright notice, and you cannot mention the copyright
// holders in advertising related to the Software without their permission.
// The Software is provided WITHOUT ANY WARRANTY, EXPRESS OR IMPLIED. This
// notice is a summary of the XORP LICENSE file; the license in that file is
// legally binding.
// $XORP: xorp/libxorp/eventloop.hh,v 1.10 2004/06/10 22:41:15 hodson Exp $
#ifndef __LIBXORP_EVENTLOOP_HH__
#define __LIBXORP_EVENTLOOP_HH__
#include <sys/time.h>
#include "timer.hh"
#include "selector.hh"
/**
* @short Event Loop.
*
* Co-ordinates interactions between a TimerList and a SelectorList
* for Xorp processes. All XorpTimer and select operations should be
* co-ordinated through this interface.
*/
class EventLoop {
public:
/**
* Constructor
*/
EventLoop();
/**
* Destructor.
*/
~EventLoop();
/**
* Invoke all pending callbacks relating to XorpTimer and file
* descriptor activity. This function may block if there are no
* selectors ready. It may block forever if there are no timers
* pending. The @ref timers_pending method can be used to detect
* whether there are timers pending, and the @ref descriptor_count
* method can be used to see if there are any select'able file
* descriptors.
*
* <pre>
EventLoop e;
...
while(e.timers_pending() || e.descriptor_count() > 0) {
e.run();
}
* </pre>
*
* Non-xorp processes which use Xorp code should create a periodic
* timer to prevent the run() function from blocking indefinitely
* when there are no pending XorpTimer or SelectList objects. The
* period of the timer will depend on the application's existing
* needs.
*
* <pre>
static bool wakeup_hook(int n) {
static int count = 0;
count += n;
printf("count = %d\n", n);
return true;
}
int main() {
... // Program initialization
// Add a Xorp EventLoop
EventLoop e;
XorpTimer wakeywakey = e.new_periodic(100, callback(wakeup_hook, 1));
// Program's main loop
for(;;) {
... do what program does in its main loop ...
e.run(); // process events
}
}
* </pre>
*/
void run();
/**
* @return reference to the @ref TimerList used by the @ref
* EventLoop instance.
*/
TimerList& timer_list() { return _timer_list; }
/**
* @return reference to the @ref SelectorList used by the @ref
* EventLoop instance.
*/
SelectorList& selector_list() { return _selector_list; }
/**
* Add a new one-off timer to the EventLoop.
*
* @param when the absolute time when the timer expires.
* @param ocb callback object that is invoked when timer expires.
* @return a @ref XorpTimer object that must be assigned to remain
* scheduled.
*/
XorpTimer new_oneoff_at(const TimeVal& when,
const OneoffTimerCallback& ocb);
/**
* Add a new one-off timer to the EventLoop.
*
* @param wait the relative time when the timer expires.
* @param ocb callback object that is invoked when timer expires.
* @return a @ref XorpTimer object that must be assigned to remain
* scheduled.
*/
XorpTimer new_oneoff_after(const TimeVal& wait,
const OneoffTimerCallback& ocb);
/**
* Add a new one-off timer to the EventLoop.
*
* @param ms the relative time in milliseconds when the timer expires.
* @param ocb callback object that is invoked when timer expires.
* @return a @ref XorpTimer object that must be assigned to remain
* scheduled.
*/
XorpTimer new_oneoff_after_ms(int ms, const OneoffTimerCallback& ocb);
/**
* Add periodic timer to the EventLoop.
*
* @param ms the period in milliseconds 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 a @ref XorpTimer object that must be assigned to remain
* scheduled.
*/
XorpTimer new_periodic(int ms, const PeriodicTimerCallback& pcb);
/**
* Add a flag setting timer to the EventLoop.
*
* @param when the absolute time when the timer expires.
*
* @param flag_ptr pointer to a boolean variable that is set to
* false when this function is called and will be set to true when
* the @ref XorpTimer expires.
*
* @return a @ref XorpTimer object that must be assigned to remain
* scheduled.
*/
XorpTimer set_flag_at(const TimeVal& when, bool* flag_ptr);
/**
* Add a flag setting timer to the EventLoop.
*
* @param wait the relative time when the timer expires.
*
* @param flag_ptr pointer to a boolean variable that is set to
* false when this function is called and will be set to true when
* the @ref XorpTimer expires.
*
* @return a @ref XorpTimer object that must be assigned to remain
* scheduled.
*/
XorpTimer set_flag_after(const TimeVal& wait, bool* flag_ptr);
/**
* Add a flag setting timer to the EventLoop.
*
* @param ms the relative time in millisecond when the timer expires.
*
* @param flag_ptr pointer to a boolean variable that is set to
* false when this function is called and will be set to true when
* the @ref XorpTimer expires.
*
* @return a @ref XorpTimer object that must be assigned to remain
* scheduled.
*/
XorpTimer set_flag_after_ms(int ms, bool* flag_ptr);
/**
* Create a custom timer associated with the EventLoop.
*
* The @ref XorpTimer object created needs to be explicitly
* scheduled with the available @ref XorpTimer methods.
*
* @param cb user callback object that is invoked when timer expires.
* @return a @ref XorpTimer object that must be assigned to remain
* scheduled.
*/
XorpTimer new_timer(const BasicTimerCallback& cb);
/**
* Add a file descriptor and callback to be invoked when
* descriptor is ready for input or output. A SelectorMask
* determines what type of I/O event will cause the callback to be
* invoked.
*
* Only one callback may be associated with each event
* type, e.g. one callback for read pending, one callback for
* write pending.
*
* If multiple event types in are associated with the same
* callback, the callback is only invoked once, but the mask
* argument passed to the callback shows multiple event types.
*
* @param fd the file descriptor.
* @param mask the @ref SelectorMask of the event types to that
* will invoke hook.
* @param cb object to be invoked when file descriptor has I/O
* pending.
* @return true on success.
*/
inline bool EventLoop::add_selector(int fd,
SelectorMask mask,
const SelectorCallback& cb);
/**
* Remove hooks associated with file descriptor.
*
* @param fd the file descriptor.
* @param event_mask mask of event types to clear.
*/
void remove_selector(int fd, SelectorMask event_mask = SEL_ALL);
/**
* @return the number of file descriptors that have registered
* callbacks with the EventLoop @ref SelectorList.
*/
size_t descriptor_count() const;
/**
* @return true if any XorpTimers are present on EventLoop's TimerList.
*/
bool timers_pending() const;
/**
* @return the number of XorpTimers present on EventLoop's TimerList.
*/
size_t timer_list_length() const;
/**
* Get current time according to EventLoop's TimerList
*/
inline void current_time(TimeVal& now) const;
private:
EventLoop(const EventLoop&); // not implemented
EventLoop& operator=(const EventLoop&); // not implemented
private:
TimerList _timer_list;
SelectorList _selector_list;
};
// ----------------------------------------------------------------------------
// Deferred definitions
inline XorpTimer
EventLoop::new_timer(const BasicTimerCallback& cb)
{
return _timer_list.new_timer(cb);
}
inline XorpTimer
EventLoop::new_oneoff_at(const TimeVal& tv, const OneoffTimerCallback& ocb)
{
return _timer_list.new_oneoff_at(tv, ocb);
}
inline XorpTimer
EventLoop::new_oneoff_after(const TimeVal& wait,
const OneoffTimerCallback& ocb)
{
return _timer_list.new_oneoff_after(wait, ocb);
}
inline XorpTimer
EventLoop::new_oneoff_after_ms(int ms, const OneoffTimerCallback& ocb)
{
return _timer_list.new_oneoff_after_ms(ms, ocb);
}
inline XorpTimer
EventLoop::new_periodic(int period_ms, const PeriodicTimerCallback& pcb)
{
return _timer_list.new_periodic(period_ms, pcb);
}
inline XorpTimer
EventLoop::set_flag_at(const TimeVal& tv, bool *flag_ptr)
{
return _timer_list.set_flag_at(tv, flag_ptr);
}
inline XorpTimer
EventLoop::set_flag_after(const TimeVal& wait, bool *flag_ptr)
{
return _timer_list.set_flag_after(wait, flag_ptr);
}
inline XorpTimer
EventLoop::set_flag_after_ms(int ms, bool *flag_ptr)
{
return _timer_list.set_flag_after_ms(ms, flag_ptr);
}
inline bool
EventLoop::add_selector(int fd,
SelectorMask mask,
const SelectorCallback& cb)
{
return _selector_list.add_selector(fd, mask, cb);
}
inline void
EventLoop::remove_selector(int fd, SelectorMask event_mask)
{
_selector_list.remove_selector(fd, event_mask);
}
inline size_t
EventLoop::descriptor_count() const {
return _selector_list.descriptor_count();
}
inline bool
EventLoop::timers_pending() const
{
return !_timer_list.empty();
}
inline size_t
EventLoop::timer_list_length() const
{
return _timer_list.size();
}
inline void
EventLoop::current_time(TimeVal& t) const
{
_timer_list.current_time(t);
}
#endif // __LIBXORP_EVENTLOOP_HH__
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