This is an attempt to unclutter the API of WpProxy and
split functionality into smaller pieces, making it easier
to work with.
In this new class layout, we have the following classes:
- WpObject: base class for everything; handles activating
| and deactivating "features"
|- WpProxy: base class for anything that wraps a pw_proxy;
| handles events from pw_proxy and nothing more
|- WpGlobalProxy: handles integration with the registry
All the other classes derive from WpGlobalProxy. The reason
for separating WpGlobalProxy from WpProxy, though, is that
classes such as WpImplNode / WpSpaDevice can also derive from
WpProxy now, without interfacing with the registry.
All objects that come with an "info" structure and have properties
and/or params also implement the WpPipewireObject interface. This
provides the API to query properties and get/set params. Essentially,
this is implemented by all classes except WpMetadata (pw_metadata
does not have info)
This interface is implemented on each object separately, using
a private "mixin", which is a set of vfunc implementations and helper
functions (and macros) to facilitate the implementation of this interface.
A notable difference to the old WpProxy is that now features can be
deactivated, so it is possible to enable something and later disable
it again.
This commit disables modules, tests, tools, etc, to avoid growing the
patch more, while ensuring that the project compiles.
There are 3 kinds of WpProxy objects:
* the ones that are created as a result of binding a global
from the registry
* the ones that are created as a result of calling into a remote
factory (wp_node_new_from_factory, etc...)
* the ones that are a local implementation of an object
(WpImplNode, etc...) and are exported
Previously the object manager was only able to track the first kind.
With these changes we can now also have globals associated with
WpProxies that were created earlier (and caused the creation of the global).
This saves some resources and reduces round-trips (in case client
code wants to change properties of an object that is locally
implemented, it shouldn't need to do a round-trip through the server)
