TypePlugin#

class TypePlugin(*args, **kwargs)#

Implementations: TypeModule

An interface that handles the lifecycle of dynamically loaded types.

The GObject type system supports dynamic loading of types. It goes as follows:

The type is initially introduced (usually upon loading the module the first time, or by your main application that knows what modules introduces what types), like this:

   new_type_id = g_type_register_dynamic (parent_type_id,
                                          "TypeName",
                                          new_type_plugin,
                                          type_flags);

where ``new_type_plugin`` is an implementation of the
``GTypePlugin`` interface.

The type’s implementation is referenced, e.g. through ref or through type_create_instance (this is being called by new) or through one of the above done on a type derived from new_type_id.
This causes the type system to load the type’s implementation by calling use and complete_type_info on new_type_plugin.
At some point the type’s implementation isn’t required anymore, e.g. after unref or type_free_instance (called when the reference count of an instance drops to zero).
This causes the type system to throw away the information retrieved from complete_type_info and then it calls unuse on new_type_plugin.
Things may repeat from the second step.

So basically, you need to implement a GTypePlugin type that carries a use_count, once use_count goes from zero to one, you need to load the implementation to successfully handle the upcoming complete_type_info call. Later, maybe after succeeding use/unuse calls, once use_count drops to zero, you can unload the implementation again. The type system makes sure to call use and complete_type_info again when the type is needed again.

TypeModule is an implementation of GTypePlugin that already implements most of this except for the actual module loading and unloading. It even handles multiple registered types per module.

Methods#

class TypePlugin

complete_interface_info(instance_type: type, interface_type: type, info: InterfaceInfo) → None#

Calls the complete_interface_info function from the GTypePluginClass of plugin. There should be no need to use this function outside of the GObject type system itself.

Parameters:

instance_type – the Type of an instantiatable type to which the interface is added
interface_type – the Type of the interface whose info is completed
info – the InterfaceInfo to fill in

complete_type_info(g_type: type, info: TypeInfo, value_table: TypeValueTable) → None#

Calls the complete_type_info function from the GTypePluginClass of plugin. There should be no need to use this function outside of the GObject type system itself.

Parameters:

g_type – the Type whose info is completed
info – the TypeInfo struct to fill in
value_table – the TypeValueTable to fill in

unuse() → None#: Calls the unuse_plugin function from the GTypePluginClass of plugin. There should be no need to use this function outside of the GObject type system itself.

use() → None#: Calls the use_plugin function from the GTypePluginClass of plugin. There should be no need to use this function outside of the GObject type system itself.