The Listener::create method now takes a set of configuration parameters
from which it constructs a listener. This removes the duplicated code and
makes the behavior of listener creation similar to other objects in
MaxScale. It also allows the configuration parameters to be stored in the
listener object itself.
The code that selects which worker to assign the DCB to is now completely
in the Listener class. This removes the need to change the ownership of a
DCB after it has been allocated.
Adding the same task twice isn't allowed. The API of the housekeeper tasks
might have to be changed in a way that makes it possible for the caller to
know whether a task has been added.
Allocating the session before a DCB guarantees that at no point will a DCB
have a null session. This further clarifies the concept of the session and
also allows the listener reference to be moved there.
Ideally, the session itself would allocate and assign the client DCB but
since the Listener is the only one who does it, it's acceptable for now.
Whenever a client DCB is accepted, a session for it is allocated. This
simplifies the handling of shared data between DCBs by allowing it to be
placed inside the session object. Currently, the data is stashed away in
the client DCB.
Allocating DCB with new allows the use of C++ objects in the DCB
struct. Also the explicit poll field can be replaced by inheriting from
MXB_POLL_DATA.
The value would otherwise be assigned outside of it and in some cases not
at all. Now all DCBs (apart from internal ones) have a valid SERVICE
pointer.
The SERV_LISTENER pointer should not be in the DCBs but in the
session. This way the listener is an attribute of a session instead of a
connection. If this is implemented, the authenticator data can be more
easily shared.
This only deactivates some of the more heavy-handed features. All files have
been formatted with the new settings, which seems to have only affected lines
which were not formatted before.
