// $Id$
//
// Copyright (C) 2006
// Fraunhofer Institut fuer offene Kommunikationssysteme (FOKUS)
// Kompetenzzentrum fuer Satelitenkommunikation (SatCom)
// Stefan Bund <stefan.bund@fokus.fraunhofer.de>
//
// This program 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 2 of the License, or
// (at your option) any later version.
//
// 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.
/** \file
\brief Scheduler non-inline non-template implementation
\idea Implement signal handling (See source for more discussion
about this)
\idea Multithreading support: To support multithreading, the
static member Scheduler::instance() must return a thread-local
value (that is Scheduler::instance() must allocate one Scheduler
instance per thread). Another possibility would be to distribute
the async load unto several threads (one scheduler for multiple
threads)
*/
// Here a basic concept of how to add signal support to the scheduler:
//
// Every signal to be reported by the scheduler will be asigned a
// generic signal handler by the scheduler. This signal handler will
// use longjmp (juck) to report this signal back to the scheduler
// main-loop.
//
// To make this safe, the main-loop will look something like:
//
// int signal = setjmp(jmpBuffer_);
// if (signal == 0) {
// // unblock all signals which are registered with the
// // scheduler
// // call epoll
// // block all relevant signals again
// }
//
// // now handle the event
//
// The signal handler is then simply defined as
//
// static void Scheduler::sigHandler(int signal)
// {
// // make sure to restore the signal handler here if
// // necessary
// longjmp(Scheduler::instance().jmpBuffer_,signal);
// }
//
// You should use sigaction to register the signal handlers and define
// a sa_mask so all Scheduler-registered signals are automatically
// *blocked* whenever one of the signals is called (including the
// called signal!) (This also means, we will have to re-register all
// signals if we change the registration of some signal since the
// sa_mask changes). This ensures, that no two signals can be
// delivered on top of each other. And of course any signal registered
// with the scheduler must be blocked as soon as it is registered with
// the scheduler.
#include "Scheduler.hh"
//#include "Scheduler.ih"
// Custom includes
#include <errno.h>
#include <sys/epoll.h>
#include "Utils/Exception.hh"
#include "Utils/MicroTime.hh"
static const int EPollInitialSize = 16;
#define prefix_
///////////////////////////////cc.p////////////////////////////////////////
prefix_ senf::Scheduler::Scheduler & senf::Scheduler::instance()
{
static Scheduler instance;
return instance;
}
prefix_ void senf::Scheduler::timeout(unsigned long timeout, TimerCallback const & cb)
{
timerQueue_.push(TimerSpec(now()+1000*timeout,cb));
}
prefix_ senf::Scheduler::Scheduler()
: epollFd_(epoll_create(EPollInitialSize))
{
if (epollFd_<0)
throw SystemException(errno);
}
prefix_ void senf::Scheduler::do_add(int fd, SimpleCallback const & cb, int eventMask)
{
FdTable::iterator i (fdTable_.find(fd));
int action (EPOLL_CTL_MOD);
if (i == fdTable_.end()) {
action = EPOLL_CTL_ADD;
i = fdTable_.insert(std::make_pair(fd, EventSpec())).first;
}
if (eventMask & EV_READ) i->second.cb_read = cb;
if (eventMask & EV_PRIO) i->second.cb_prio = cb;
if (eventMask & EV_WRITE) i->second.cb_write = cb;
epoll_event ev;
memset(&ev,0,sizeof(ev));
ev.events = i->second.epollMask();
ev.data.fd = fd;
if (epoll_ctl(epollFd_, action, fd, &ev)<0)
throw SystemException(errno);
}
prefix_ void senf::Scheduler::do_remove(int fd, int eventMask)
{
FdTable::iterator i (fdTable_.find(fd));
if (i == fdTable_.end())
return;
if (eventMask & EV_READ) i->second.cb_read = 0;
if (eventMask & EV_PRIO) i->second.cb_prio = 0;
if (eventMask & EV_WRITE) i->second.cb_write = 0;
epoll_event ev;
memset(&ev,0,sizeof(ev));
ev.events = i->second.epollMask();
ev.data.fd = fd;
int action (EPOLL_CTL_MOD);
if (ev.events==0) {
action = EPOLL_CTL_DEL;
fdTable_.erase(i);
}
if (epoll_ctl(epollFd_, action, fd, &ev)<0)
throw SystemException(errno);
}
prefix_ int senf::Scheduler::EventSpec::epollMask()
const
{
int mask (0);
if (cb_read) mask |= EPOLLIN;
if (cb_prio) mask |= EPOLLPRI;
if (cb_write) mask |= EPOLLOUT;
return mask;
}
prefix_ void senf::Scheduler::process()
{
terminate_ = false;
while (! terminate_) {
MicroTime timeNow = now();
while ( ! timerQueue_.empty() && timerQueue_.top().timeout <= timeNow ) {
timerQueue_.top().cb();
timerQueue_.pop();
}
if (terminate_)
return;
int timeout = timerQueue_.empty() ? -1 : int((timerQueue_.top().timeout - timeNow)/1000);
struct epoll_event ev;
int events = epoll_wait(epollFd_, &ev, 1, timeout);
if (events<0)
// Hmm ... man epoll says, it will NOT return with EINTR. I hope, this is true :-)
throw SystemException(errno);
if (events==0)
// Timeout .. the handler will be run when going back to the loop top
continue;
FdTable::iterator i = fdTable_.find(ev.data.fd);
BOOST_ASSERT (i != fdTable_.end() );
// \todo Make this more efficient. Instead of copying the event-spec it should be
// revalidated by monitoring add/remove calls
EventSpec spec (i->second);
unsigned extraFlags (0);
if (ev.events & EPOLLHUP) extraFlags |= EV_HUP;
if (ev.events & EPOLLERR) extraFlags |= EV_ERR;
if (ev.events & EPOLLIN) {
BOOST_ASSERT(spec.cb_read);
spec.cb_read(EventId(EV_READ | extraFlags));
}
else if (ev.events & EPOLLPRI) {
BOOST_ASSERT(spec.cb_prio);
spec.cb_prio(EventId(EV_PRIO | extraFlags));
}
else if (ev.events & EPOLLOUT) {
BOOST_ASSERT(spec.cb_write);
spec.cb_write(EventId(EV_WRITE | extraFlags));
}
else {
// This branch is only taken, if HUP or ERR is signaled but none of IN/OUT/PRI.
// In this case we will signal all registered callbacks. The callbacks must be
// prepared to be called multiple times if they are registered to more than
// one event.
if (spec.cb_write)
spec.cb_write(EventId(extraFlags));
if (spec.cb_prio)
spec.cb_prio(EventId(extraFlags));
if (spec.cb_read)
spec.cb_read(EventId(extraFlags));
}
}
}
///////////////////////////////cc.e////////////////////////////////////////
#undef prefix_
// Local Variables:
// mode: c++
// fill-column: 100
// c-file-style: "senf"
// indent-tabs-mode: nil
// ispell-local-dictionary: "american"
// compile-command: "scons -u test"
// comment-column: 40
// End: