An xdg_imported resource must be created no matter whether there is an
exported surface with the specified handle.
This change fixes handling of that case in kwaylandserver by introducing
a dummy imported object.
If there is no exported surface with the given handle, the compositor
should create an xdg_imported resource and immediately send the
destroyed event.
A dummy imported object is needed because generated code sets resource
implementation; otherwise we would set an implementation without any
user data to mark the resource as inert.
There's no point for using the d-pointer pattern because the importer
and the exporter classes are private already, they are not exposed in
public api.
Currently, testXdgForeign fails because imported and exported resources
are destroyed immediately from destructor request handlers and code that
performs cleanup in the exported-imported mapping tables accesses the
dangling pointers.
Previously, it wasn't an issue because the destruction of exported and
imported resources was delayed using QObject::deleteLater().
Summary:
Implement the "foreign" wayland protocol.
A client can export a surface with an unique string as handle,
then another client can refer to that surface and set an own surface as
child of that surface.
Potential use cases are out-of-process dialogs, such as file dialogs,
meant to be used by sandboxed processes that may not have the access
it needs to implement such dialogs.
The handle needs to be shared between the processes with other means,
such as dbus or command line paramenters.
The public api of the server side only tracks parent/child relationships as this is the only data kwin would need it for, the rest of the api is not exported so should be safer from eventual protocol changes
Test Plan:
the autotest works, but has a lot of random crashes when deleting surfaces,
unfortunately backtraces don't tell much and the crashes never occur when running into valgrind
behavior may still be wrong, depending on how the protocol is supposed
to work if more clients try to set the same exported surface as parent
Reviewers: #plasma, #kwin, davidedmundson, graesslin
Reviewed By: #plasma, #kwin, graesslin
Subscribers: davidedmundson, graesslin, plasma-devel, #frameworks
Tags: #frameworks, #plasma_on_wayland
Differential Revision: https://phabricator.kde.org/D7369
