GI.GObject.Interfaces.TypePlugin

An interface that handles the lifecycle of dynamically loaded types.

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

1. 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: ``c 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.
2. The type's implementation is referenced, e.g. through [[e-mail]] or through [[e-mail]_create_instance] (this is being called by [[e-mail]]) or through one of the above done on a type derived from new_type_id.
3. This causes the type system to load the type's implementation by calling [[e-mail]] and [[e-mail]_type_info] on new_type_plugin.
4. At some point the type's implementation isn't required anymore, e.g. after [[e-mail]] or [[e-mail]_free_instance] (called when the reference count of an instance drops to zero).
5. This causes the type system to throw away the information retrieved from [[e-mail]_type_info] and then it calls [[e-mail]] on new_type_plugin.
6. 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 [[e-mail]_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 [[e-mail]] and [[e-mail]_type_info] again when the type is needed again.

[e-mail]

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.

Exported types

newtype TypePlugin

Memory-managed wrapper type.

Constructors

TypePlugin (ManagedPtr TypePlugin)

Instances

Eq TypePlugin

Defined in GI.GObject.Interfaces.TypePlugin

Methods

(==) :: TypePlugin -> TypePlugin -> Bool

(/=) :: TypePlugin -> TypePlugin -> Bool

BoxedPtr TypePlugin

Defined in GI.GObject.Interfaces.TypePlugin

Methods

boxedPtrCopy :: TypePlugin -> IO TypePlugin

boxedPtrFree :: TypePlugin -> IO ()

ManagedPtrNewtype TypePlugin

Defined in GI.GObject.Interfaces.TypePlugin

Methods

toManagedPtr :: TypePlugin -> ManagedPtr TypePlugin

class (ManagedPtrNewtype o, IsDescendantOf TypePlugin o) => IsTypePlugin o

Type class for types which implement TypePlugin.

Instances

(ManagedPtrNewtype o, IsDescendantOf TypePlugin o) => IsTypePlugin o

Defined in GI.GObject.Interfaces.TypePlugin

Methods

Click to display all available methods, including inherited ones

Methods

completeInterfaceInfo, completeTypeInfo, unuse, use.

Getters

None.

Setters

None.

completeInterfaceInfo

typePluginCompleteInterfaceInfo

Arguments

:: (HasCallStack, MonadIO m, IsTypePlugin a)

=> a

plugin: the TypePlugin

-> GType

instanceType: the GType of an instantiatable type to which the interface is added

-> GType

interfaceType: the GType of the interface whose info is completed

-> InterfaceInfo

info: the InterfaceInfo to fill in

-> m ()

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

completeTypeInfo

typePluginCompleteTypeInfo

Arguments

:: (HasCallStack, MonadIO m, IsTypePlugin a)

=> a

plugin: a TypePlugin

-> GType

gType: the GType whose info is completed

-> TypeInfo

info: the TypeInfo struct to fill in

-> TypeValueTable

valueTable: the TypeValueTable to fill in

-> m ()

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

unuse

typePluginUnuse

Arguments

:: (HasCallStack, MonadIO m, IsTypePlugin a)

=> a

plugin: a TypePlugin

-> m ()

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

use

typePluginUse

Arguments

:: (HasCallStack, MonadIO m, IsTypePlugin a)

=> a

plugin: a TypePlugin

-> m ()

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