/*
Copyright (C) 2012-2015 John W. Eaton
This file is part of Octave.
Octave is free software; you can redistribute it and/or modify it
under the terms of the GNU General Public License as published by the
Free Software Foundation; either version 3 of the License, or (at your
option) any later version.
Octave 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 Octave; see the file COPYING. If not, see
.
*/
#if !defined (octave_event_queue_h)
#define octave_event_queue_h 1
#include
#include
#include "action-container.h"
class
event_queue : public action_container
{
public:
event_queue (void) : fifo () { }
// Destructor should not raise an exception, so all actions
// registered should be exception-safe (but setting error_state is
// allowed). If you're not sure, see event_queue_safe.
~event_queue (void) { run (); }
void add (elem *new_elem)
{
fifo.push (new_elem);
}
void run_first (void)
{
if (! empty ())
{
// No leak on exception!
std::auto_ptr ptr (fifo.front ());
fifo.pop ();
ptr->run ();
}
}
void discard_first (void)
{
if (! empty ())
{
elem *ptr = fifo.front ();
fifo.pop ();
delete ptr;
}
}
size_t size (void) const { return fifo.size (); }
protected:
std::queue fifo;
private:
// No copying!
event_queue (const event_queue&);
event_queue& operator = (const event_queue&);
};
// Like event_queue, but this one will guard against the
// possibility of seeing an exception (or interrupt) in the cleanup
// actions. Not that we can do much about it, but at least we won't
// crash.
class
event_queue_safe : public event_queue
{
private:
static void gripe_exception (void);
public:
event_queue_safe (void) : event_queue () { }
~event_queue_safe (void)
{
while (! empty ())
{
try
{
run_first ();
}
catch (...) // Yes, the black hole. Remember we're in a dtor.
{
gripe_exception ();
}
}
}
private:
// No copying!
event_queue_safe (const event_queue_safe&);
event_queue_safe& operator = (const event_queue_safe&);
};
#endif