For most interfaces, the client announcing its supported version is
sufficient - the objects are all created server-side. For some
interfaces (ei_connection_setup and ei_callback right now) the client
needs to know the server-supported version.
So let's switch the current ei_connection_setup.version event (used to
negotiate ei_connection_setup's version) to a generic
`interface_version` event. This way our EIS implementation can
eventually send a version for ei_callback as well.
Leave the ei_callback as-is and instead add ei_pingpong for the same
thing initiated by the server. The interface is otherwise identical but
for the direction it is supposed to flow.
This reduces the possibility of a client accidentally sending a
request when it is supposed to handle an event or vice versa.
This is effectively the same as connection.sync, but goes the other way.
This adds the ei_callback.done request.
In libeis this is (currently) enforced immediately after sending the
connection object. Not required there and makes the code a bit messier
but this way we can ensure that any client library handles that part of
the code.
This event is to notify the client that an object used in a request was
unknown. This allows the client to work around race conditions like
binding to a seat that was removed.
This is currently the server-side only which is probably enough for now.
The only client-side created objects we have are the callbacks.
This changes the initial connection negotiation to have the
ei_connection_setup as the pre-existing object id 0. Once the client has
sent all the data to set up the connection, the EIS implementation
replies with a new object ID that is the ei_connection protocol object,
i.e. the main object.
This allows for version negotiation of our main protocol object.
This allows us to have a device support multiple interfaces and evolve
those interfaces individually, e.g. add things to the keyboard interface
without having to bump the touchscreen interface.
Note that due to a name clash with the existing struct ei_touch public
API the protocol interface is named touchscreen.
The idea here is that the client announces the interfaces it can support
and their version (including the core ei_connection). The server can
then send the various bits based on those versions, where applicable.
This replaces the connect/connect_done and version/get_version requests.
Immediately after connecting, the server sends an ei_protocol_setup
event to the client with the ID of the object and the server's highest
supported version number (of this object).
This is a one-shot object that the client can use to configure its name
and whether it is a sender or receiver context. Once .done is sent, the
object is discarded.
The server version is sent along to the client to allow for requests to
be added to this object in the future.
As a fixme left: the client now assumes to be connected as soon as the
.done request is sent and the following sync event is received. The
EIS implementation will not have actually eis_client_connect()ed the
client yet, but it's good enough for now.
Arguably, the CONNECTED event is superfluous anyway since *any* event
other than DISCONNECTED indicates connected status. CONNECTED is a
leftover from when the client created devices and needed to know if it's
worth doing so.
Directly copied from wayland. Note that while the wayland protocol
specifies the data is the last event serial in our case here it's just
0 since we don't have any event serials (yet).
The sync request is currently triggered after connection, merely to
ensure it works, it's not actually needed.
In the protocol this is a simple rename but in the implementation we can
now separate the protocol object out from the ei/ei-client context
itself by having the ei_connection objects.
This protocol is wayland-like though it uses a slightly different
message format. The XML file uses the same structure, except for the
"fixed" type which is "float" here.
The scanner uses a jinja template to generate source and header files
for ei and eis which are now used instead of the protobuf-generated
objects. Note that the scanner is a minimal working version, some
features like enum value checks are not yet implemented.
Unlike wayland we do not need to generate the libwayland-like library,
we only need the wire protocol parser - some shortcuts can thus be taken.
To keep the changes simple, the protocol currently is a flat protocol
with only one interface and all messages copied over from the previous
ei.proto file. In future commits, this will be moved to the respective
interfaces instead.
