The interface for canceling calls is now geared towards the needs
of sessions. Basically the idea is as follows:
class MyFilterSession : public maxscale::FilterSession
{
...
int MyFilterSession::routeQuery(GWBUF* pPacket)
{
...
if (needs_to_be_delayed())
{
Worker* pWorker = Worker::current();
void* pTag = this;
pWorker->delayed_call(5000, pTag, this,
&MyFilterSession::delayed_routeQuery,
pPacket);
return 1;
}
...
}
bool MyFilterSession::delayed_routeQuery(Worker::Call:action_t action,
GWBUF* pPacket)
{
if (action == Worker::Call::EXECUTE)
{
routeQuery(pPacket);
}
else
{
ss_dassert(action == Worker::Call::CANCEL);
gwbuf_free(pPacket);
}
return false;
}
~MyFilterSession()
{
void* pTag = this;
Worker::current()->cancel_delayed_calls(pTag);
}
}
The alternative, returning some key that the caller must keep
around seems more cumbersome for the general case.
It's now possible to provide Worker with a function to call
at a later time. It's possible to provide a function or a
member function (with the object), taking zero or one argument
of any kind. The argument must be copyable.
There's currently no way to cancel a call, which must be added
as typically the delayed calling is associated with a session
and if the session is closed before the delayed call is made,
bad things are likely to happen.
