typedef int IOM_CHAINED;

/////////////////////////////////////////////////////////////////////////////

#define SvWATCHER(sv) (perl_watcher *)SvPTR (sv, IOM_CLASS "::watcher")

struct perl_watcher
{
  SV *cbsv;
  HV *self;

  perl_watcher ()
  : cbsv (0)
  {
  }

  ~perl_watcher ()
  {
    SvREFCNT_dec (cbsv);
  }

  void cb (SV *cb)
  {
    SvREFCNT_dec (cbsv);
    cbsv = newSVsv (cb);
  }

  void invoke (const char *type, SV *self, int arg = -1);
};

void
perl_watcher::invoke (const char *type, SV *self, int arg)
{
  dSP;

  ENTER;
  SAVETMPS;

  PUSHMARK (SP);

  XPUSHs (sv_2mortal (self));

  if (arg >= 0)
    XPUSHs (sv_2mortal (newSViv (arg)));

  PUTBACK;
  call_sv (cbsv, G_VOID | G_EVAL | G_DISCARD);
  SPAGAIN;

  PUTBACK;
  FREETMPS;
  LEAVE;

  if (SvTRUE (ERRSV))
    rxvt_warn ("%s callback evaluation error: %s", type, SvPV_nolen (ERRSV));
}

#define newSVtimer(timer) new_ref ((timer)->self, IOM_CLASS "::timer")
#define SvTIMER(sv) (timer *)(perl_watcher *)SvPTR ((sv), IOM_CLASS "::timer")

struct timer : perl_watcher, time_watcher
{
  tstamp interval;

  timer ()
  : time_watcher (this, &timer::execute)
  {
  }

  void execute (time_watcher &w)
  {
    if (interval)
      start (at + interval);

    invoke (IOM_CLASS "::timer", newSVtimer (this));
  }
};

#define newSViow(iow) new_ref ((iow)->self, IOM_CLASS "::iow")
#define SvIOW(sv) (iow *)(perl_watcher *)SvPTR ((sv), IOM_CLASS "::iow")

struct iow : perl_watcher, io_watcher
{
  iow ()
  : io_watcher (this, &iow::execute)
  {
  }

  void execute (io_watcher &w, short revents)
  {
    invoke (IOM_CLASS "::iow", newSViow (this), revents);
  }
};

#define newSViw(iw) new_ref ((iw)->self, IOM_CLASS "::iw")
#define SvIW(sv) (iw *)(perl_watcher *)SvPTR ((sv), IOM_CLASS "::iw")

struct iw : perl_watcher, idle_watcher
{
  iw ()
  : idle_watcher (this, &iw::execute)
  {
  }

  void execute (idle_watcher &w)
  {
    invoke (IOM_CLASS "::iw", newSViw (this));
  }
};

#define newSVpw(pw) new_ref ((pw)->self, IOM_CLASS "::pw")
#define SvPW(sv) (pw *)(perl_watcher *)SvPTR ((sv), IOM_CLASS "::pw")

struct pw : perl_watcher, child_watcher
{
  pw ()
  : child_watcher (this, &pw::execute)
  {
  }

  void execute (child_watcher &w, int status)
  {
    invoke (IOM_CLASS "::pw", newSVpw (this), status);
  }
};