Now that we have 64 bit integers on the wire and 64 bit object IDs,
we're already different to the Wayland protocol. So we might as well get
the full length and split message length and opcode again to make header
parsing and composing simpler.
This effectively reverts commit bf45a7182cb2f4c13f11e141fc846244d3ac6212.
Previously, we'd send one interface_version event for "ei_handshake"
immediately but all others after the client requests handshake.finish.
This was too confusing to document and not clear how it would work, so
let's make this simpler by splitting it up.
There is now a handshake_version event from the server, sent immediately
on connection that denotes the maximum version number for the interface.
And a handshake_version request from the client which must be the first
one by the client.
These were previously (1 << cap) for convenience but that results in the
capability mask on the wire starting at 2 - which is a bit awkward.
Lets shift them down by one so we start the mask at 1.
Add another run to the XML parser so we parse enums before Arguments
that cross-reference enums from other interfaces.
This also fixes a type bug - the enum name string was passed to
Argument.create() as Enum and no-one noticed.
No real functional changes, this just changes the message header to be
header = [object_id, msglen << 16 | opcode].
The only difference to the wayland protocol is now the fixed vs float
but otherwise tools that can print/debug/mangle the wayland protocol
should be easily adjustable for this protocol too..
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.
The Target was specific to libei/libeis, it resolved to "ei" or
"eis_client" depending on which component we were building. But that's
specific to our C implementation here, so let's push it into our C
implementation templates.
