This fixes a race condition that can happen when a proxy requests a new feature
(for example WP_NODE_FEATURE_PORTS) and PipeWire destroys the proxy before the
activation finishes. This race condition was causing the current activation
transition of a proxy to never finish, creating a memory leak because the
transition holds a strong reference of the proxy. Appart from this, since the
activation never finishes, WirePlumber could wait forever and not respond to
other requests.
This also removes the wp_proxy_watch_bind_error() API for subclasses as it is
not needed anymore.
Globals can be removed by the object manager when their associated proxy is
currently being bound. Adding extra checks in wp_global_proxy_bin() to return
a transition error avoids binding the proxy when that happens.
Now the WpPipewireObject interface is directly implemented by the mixin
and there is another interface that users of the mixin must implement
in order for the mixin to work proprely.
A lot of manual stuff that proxy classes had to do before are now
in the mixin. Also most of the data that would normally reside in Private
structures is now in the mixin data structure (stored as qdata on the object).
This is achieving the best amount of code reuse so far.
For impl objects (WpImpl*) there are also default implementations of the
standard pipewire object methods and the INFO & PARAM_* features are
more coherently enabled during the whole lifetime of these objects.
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.
