Finding a Way(land)
In the next round we shall be sending it the messages we have so lovingly composed from whole cloth and see if it reacts the same way as it did when the same bytes were sent from weston-info
And the answer is … yes, pretty much. We had to fix up our string
parsing to make sense of the replies, but watch:
psadan.core> (def connection (conn/open-connection "/home/dan/private/wayland-0"))
#'psadan.core/connection
psadan.core> (defn test-send-message []
(let [registry
(conn/remember-object
connection
{:id 2 :interface (proto/find-interface-by-name :wl_registry)})
done-cb
(conn/remember-object
connection
{:id 3 :interface (proto/find-interface-by-name :wl_callback)})
]
(conn/write-buffer connection
(buf/pack-message connection (:display connection)
:requests :get_registry [registry]))
(conn/write-buffer connection
(buf/pack-message connection (:display connection)
:requests :sync [done-cb]))
registry))
#'psadan.core/test-send-message
psadan.core> (test-send-message)
{:id 2, :interface {:index 1, :name :wl_registry, :requests ({:index 0, :name :bind, :summary "bind an object to the display", :args ({:name "name", :type :uint, :interface nil} {:name "id", :type :new_id, :interface nil})}), :events ({:index 0, :name :global, :summary "announce global object", :args ({:name "name", :type :uint, :interface nil} {:name "interface", :type :string, :interface nil} {:name "version", :type :uint, :interface nil})} {:index 1, :name :global_remove, :summary "announce removal of global object", :args ({:name "name", :type :uint, :interface nil})}), :enums ()}}
psadan.core> (def received (read-buffer connection))
#'psadan.core/received
psadan.core> (pprint (map (fn [x] [(:object-id x) (:message x) (:args x)]) (buf/parse-messages received connection :events)))
nil
([2 :global (1 "wl_display" 1)]
[2 :global (2 "wl_compositor" 2)]
[2 :global (3 "screenshooter" 1)]
[2 :global (4 "text_cursor_position" 1)]
[2 :global (5 "text_model_factory" 1)]
[2 :global (6 "wl_data_device_manager" 1)]
[2 :global (7 "wl_shm" 1)]
[2 :global (8 "wl_seat" 1)]
[2 :global (9 "input_method" 1)]
[2 :global (10 "wl_output" 1)]
[2 :global (11 "wl_drm" 1)]
[2 :global (12 "wl_shell" 1)]
[2 :global (13 "desktop_shell" 1)]
[2 :global (14 "screensaver" 1)]
[2 :global (15 "input_panel" 1)]
[2 :global (16 "workspace_manager" 1)]
[3 :done (58)]
[1 :delete_id (3)])
My interpretation of what’s happening here is that we’re sending to
the server a ‘tell object 2 about all your global objects’ message,
followed by a ‘tell object 3 done when you’re finished doing stuff’
message, and as you can see from the output, the reply is a bunch of
ids for global objects sent to object 2, a done event sent to object
3, and then a delete_id event for object 3 sent to object 1. I’m
actually not sure why that last one triggers, as I don’t think I asked
it to. Perhaps it’s just tidying up for me.
I’m also handwaving – if not actually handdrowning – a litle bit,
because really … are these :global messages sent to object 2 or
from object 2? For the moment, I am using the two directions
interchangeably, which is probably not a recipe for an easier future
life, but in the meantime I can continue to tread water.
It’s instructive, or at least reassuring, to compare this stuff with
what weston-info says:
interface: 'wl_display', version: 1, name: 1
interface: 'wl_compositor', version: 2, name: 2
interface: 'screenshooter', version: 1, name: 3
interface: 'text_cursor_position', version: 1, name: 4
interface: 'text_model_factory', version: 1, name: 5
interface: 'wl_data_device_manager', version: 1, name: 6
interface: 'wl_shm', version: 1, name: 7
formats: XRGB8888 ARGB8888
interface: 'wl_seat', version: 1, name: 8
capabilities: pointer keyboard
interface: 'input_method', version: 1, name: 9
interface: 'wl_output', version: 1, name: 10
x: 0, y: 0,
physical_width: 1024 mm, physical_height: 640 mm,
make: 'xwayland', model: 'none',
subpixel_orientation: unknown, output_tranform: normal,
mode:
width: 1024 px, height: 640 px, refresh: 60 Hz,
flags: current preferred
interface: 'wl_drm', version: 1, name: 11
interface: 'wl_shell', version: 1, name: 12
interface: 'desktop_shell', version: 1, name: 13
interface: 'screensaver', version: 1, name: 14
interface: 'input_panel', version: 1, name: 15
interface: 'workspace_manager', version: 1, name: 16
Top Wayland tip for today: it appears to be the case that you can make
the C library clients log protocol exchanges to stderr by putting
WAYLAND_DEBUG=client in the environment. When doing that it’s clear
to see that weston-info is making a couple of additional requests
that we’re not. We could add them, but I think the more pressing
concern is to make it do something with the events we’re getting
already – if it’s sending us details of global objects that we might
need to know about, we should at a minimum be storing those details
somewhere instead of throwing them away …
Syndicated 2013-03-14 13:32:01 from diary at Telent Netowrks
