The primary use-case for these properties in libei itself was to send
some fixed information (pid, cmdline and conection type). In the portal
case, these can be obtained out-of-band via the portal. In the
non-portal case these can be obtained from the socket itself (fetch pid,
look up /proc/pid/cmdline) which is just as reliable as trusting
whatever libei sends.
The only other use-case for the properties was the activation id in the
InputCapture::Activated portal signal. This can be achieved with a
serial in the START_EMULATING event.
The original idea here was that we would have an EmulatedInput portal
that allows the application to connect directly to the EIS
implementation to exchange input events - instead of ping-ponging DBus
events through the xdg-desktop-portal as the RemoteDesktop portal
requires.
This is no longer accurate, there are suggested PRs open to add
RemoteDesktop.ConnectToEIS to achieve the same through the existing
RemoteDesktop interface [1] and to add a new InputCapture portal
to allow for events to be sent to a libei receiver context [2].
The example EmulatedInput portal is thus superfluous and can be removed
from here.
We could switch the ei_setup_backend_portal() code to use RemoteDesktop
or InputCapture, depending on the context type, the utility of this is
questionable. Interaction with portals is complex, one needs to
implement the Session/Request interfaces correctly and in the case of
InputCapture also handle the complex zones/pointer barrier setup.
libportal does some of this (or it will, anyway) so it's more useful for
an application to use libportal and then just pass the received fd to
libei.
If there is a future need for this to be handled as part of libei, we
can (re)implement this, but for now it's best to just purge all of this.
[1] https://github.com/flatpak/xdg-desktop-portal/pull/762
[2] https://github.com/flatpak/xdg-desktop-portal/pull/714
Prints out a YAML-compatible list of events for debugging.
This tool also takes a --socketfd argument which names the fd number
that the EIS connection is on. This allows the tool to be started from
some other process that does the EIS connection, e.g. a portal
implementation.
