The current implementation uses a sort of "manual reference counting"; any
place which may be the last one using the connection checks if it is indeed
the last one, and if so, deletes the connection object.
With recent changes this has become unwields, as there are too many cases
to track.
To fix, we separate the connection into two streams: a read() stream that
is internally serialized (only one request is parsed at a time) and that
returns when there are no more requests to parse, and a respond() stream
that is also internally serialized, and termiantes when the last response
has been written. The caller then waits on the two streams with when_all().
When client closes the connection in one direction, make httpd close the
other direction too. This way, httpd will send back a <FIN> packet to
client after receiving client's <FIN> packet.
The result is not used for anything and I am not sure what it could be
used for, as the result carries little (write) to none (flush)
information. So I went ahead and simplified it to be future<> so that
it is easier to return it in places which expect future<>.
This patches shows what change is needed for http to run with multiple
event loops. This is not very useful still because actual work is not
yet distributed.
The imperative form suggests that in addition to returning a future it
performs some action and thus is needed regardless of whether we want
to add a callback or not. But in fact it does not do anything, just
gives away a future.
Signed-off-by: Tomasz Grabiec <tgrabiec@cloudius-systems.com>
Instead of returning a pollable_fd from server_socket::accept(), return
a new abstract class connected_socket, which is able to provide an
input_stream and an output_stream to the caller.
Instead of returning the Unix-tied pollable_fd, return an abstract
server_socket class which is then implement atop pollable_fd, but can
be replaced with a native implementation.
Since they are going to be the abstract interface to both the bsd socket
layer and the native tcp stack, rename them to more generic names -
input_stream and output_stream.
