PipeWire can request to destroy the allocated buffers anytime. This
isn't a problem for us, since the screencopy protocol can handle
disappearing buffers. The only thing we have to do is not to use a
destroyed buffer.
The enum xdpw_frame_state is used to track the state of the xdpw_frame through
the screencopy callbacks. xdpw_wlr_stream_finish is used as the new
endpoint of the screencopy callbacks. Here we clean up the
screencopy_frame, enqueue the pipewire buffer and restart the screencopy
loop if needed.
Sometimes it can happen that the first frame of the active stream
triggers the renegotiation and destroy the frame without copy and with
that starting the fps_limit counter. This triggers an assert in
fps_limit_measure_end. To avoid it, we only engage the fps_limiter after
a frame was copied successfully.
Instead of using one wl_buffer to export buffers from wlroots and then
copy the content into the buffer dequed from pipewire, we can create a
wl_buffer for each pipewire buffer directly at allocation time and
attach it to the data attribute. Those wl_buffers can be directly handed
over to the wlroots screencopy protocol and so removing one copy.
Since we gather the information of the currently used buffer on
importing it, we can check if the imported and the announce buffer by
wlroots are compatible.
Also the comparison between the announced buffer properties and the
format used by the pipewire stream was moved to wlr_frame_buffer_done.
This lets us implement all checks in the same callback and makes it
easier to extend those checks for future dmabuf sharing.
Since we are driving the screencast there are no events on the pipewire loop
calling the on_event callback. We want to import and export (if possible) on
every frame of the wlroots loop, so this event is no longer needed.
The default node_id is SPA_ID_INVALID.
We are casting pipewire uint32_t node_id to int for printing since they are
currently staying in the range of low integer numbers. This makes
spotting an uninitialized node_id (casted to -1) much easier. Should be
corrected if that becomes an issue in the future.
This makes xdpw exit when either the D-Bus daemon, the Wayland
compositor or Pipewire is shut down. This avoids having dangling
non-functional xdpw instances, e.g. when restarting the compositor.
To test, start Sway nested in Sway, run xdpw with
WAYLAND_DISPLAY=wayland-2, and exit the nested Sway.
Add a dbus-update-activation-environment invocation that users can
add to their config file. This should work for most users, assuming
Sway, systemd, and D-Bus activation.
The --systemd flag also imports the variables to the systemd user
session.
Add -r flag to xdpw to make sure any currently running process gets
replaced.
Remove the /usr/lib/xdg-desktop-portal invocation since xdpw can now be
replaced.
Adapt the wording to the latest xdpw changes.
