Gio.IOExtensionPoint¶

record (struct)

GIOExtensionPoint provides a mechanism for modules to extend the functionality of the library or application that loaded it in an organized fashion.

An extension point is identified by a name, and it may optionally require that any implementation must be of a certain type (or derived thereof). Use IOExtensionPoint.register to register an extension point, and IOExtensionPoint.set_required_type to set a required type.

A module can implement an extension point by specifying the GObject.Type that implements the functionality. Additionally, each implementation of an extension point has a name, and a priority. Use IOExtensionPoint.implement to implement an extension point.

GIOExtensionPoint *ep;

// Register an extension point
ep = g_io_extension_point_register ("my-extension-point");
g_io_extension_point_set_required_type (ep, MY_TYPE_EXAMPLE);

// Implement an extension point
G_DEFINE_TYPE (MyExampleImpl, my_example_impl, MY_TYPE_EXAMPLE)
g_io_extension_point_implement ("my-extension-point",
                                my_example_impl_get_type (),
                                "my-example",
                                10);

It is up to the code that registered the extension point how it uses the implementations that have been associated with it. Depending on the use case, it may use all implementations, or only the one with the highest priority, or pick a specific one by name.

To avoid opening all modules just to find out what extension points they implement, GIO makes use of a caching mechanism, see gio-querymodules. You are expected to run this command after installing a GIO module.

The GIO_EXTRA_MODULES environment variable can be used to specify additional directories to automatically load modules from. This environment variable has the same syntax as the PATH. If two modules have the same base name in different directories, then the latter one will be ignored. If additional directories are specified GIO will load modules from the built-in directory last.

Methods¶

get_extension_by_name¶

def get_extension_by_name(self, name: str) -> IOExtension

Finds a IOExtension for an extension point by name.

Parameters:

name — the name of the extension to get

get_extensions¶

def get_extensions(self) -> list[IOExtension]

Gets a list of all extensions that implement this extension point. The list is sorted by priority, beginning with the highest priority.

get_required_type¶

def get_required_type(self) -> type | GObject.Type

Gets the required type for extension_point.

set_required_type¶

def set_required_type(self, type: type | GObject.Type) -> None

Sets the required type for extension_point to type. All implementations must henceforth have this type.

Parameters:

type — the GType to require

Static functions¶

implement¶

@staticmethod
def implement(extension_point_name: str, type: type | GObject.Type, extension_name: str, priority: int) -> IOExtension

Registers type as extension for the extension point with name extension_point_name.

If type has already been registered as an extension for this extension point, the existing IOExtension object is returned.

Parameters:

extension_point_name — the name of the extension point
type — the GType to register as extension
extension_name — the name for the extension
priority — the priority for the extension

lookup¶

@staticmethod
def lookup(name: str) -> IOExtensionPoint

Looks up an existing extension point.

Parameters:

name — the name of the extension point

register¶

@staticmethod
def register(name: str) -> IOExtensionPoint

Registers an extension point.

Parameters:

name — The name of the extension point