Copyright | Will Thompson Iñaki García Etxebarria and Jonas Platte |
---|---|
License | LGPL-2.1 |
Maintainer | Iñaki García Etxebarria |
Safe Haskell | None |
Language | Haskell2010 |
GI.GObject.Interfaces.TypePlugin
Description
The GObject type system supports dynamic loading of types.
The TypePlugin
interface is used to handle the lifecycle
of dynamically loaded 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:
C code
new_type_id = g_type_register_dynamic (parent_type_id, "TypeName", new_type_plugin, type_flags);
where newTypePlugin
is an implementation of the
TypePlugin
interface.
- The type's implementation is referenced, e.g. through
typeClassRef
or throughg_type_create_instance()
(this is being called byg_object_new()
) or through one of the above done on a type derived fromnewTypeId
. - This causes the type system to load the type's implementation by
calling
typePluginUse
andtypePluginCompleteTypeInfo
onnewTypePlugin
. - At some point the type's implementation isn't required anymore,
e.g. after
typeClassUnref
ortypeFreeInstance
(called when the reference count of an instance drops to zero). - This causes the type system to throw away the information retrieved
from
typePluginCompleteTypeInfo
and then it callstypePluginUnuse
onnewTypePlugin
. - Things may repeat from the second step.
So basically, you need to implement a TypePlugin
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
typePluginCompleteTypeInfo
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
typePluginUse
and typePluginCompleteTypeInfo
again
when the type is needed again.
TypeModule
is an implementation of TypePlugin
that already
implements most of this except for the actual module loading and
unloading. It even handles multiple registered types per module.
Synopsis
- newtype TypePlugin = TypePlugin (ManagedPtr TypePlugin)
- class (ManagedPtrNewtype o, IsDescendantOf TypePlugin o) => IsTypePlugin o
- typePluginCompleteInterfaceInfo :: (HasCallStack, MonadIO m, IsTypePlugin a) => a -> GType -> GType -> InterfaceInfo -> m ()
- typePluginCompleteTypeInfo :: (HasCallStack, MonadIO m, IsTypePlugin a) => a -> GType -> TypeInfo -> TypeValueTable -> m ()
- typePluginUnuse :: (HasCallStack, MonadIO m, IsTypePlugin a) => a -> m ()
- typePluginUse :: (HasCallStack, MonadIO m, IsTypePlugin a) => a -> m ()
Exported types
newtype TypePlugin Source #
Memory-managed wrapper type.
Constructors
TypePlugin (ManagedPtr TypePlugin) |
Instances
Eq TypePlugin Source # | |
Defined in GI.GObject.Interfaces.TypePlugin | |
BoxedPtr TypePlugin Source # | |
Defined in GI.GObject.Interfaces.TypePlugin | |
ManagedPtrNewtype TypePlugin Source # | |
Defined in GI.GObject.Interfaces.TypePlugin Methods |
class (ManagedPtrNewtype o, IsDescendantOf TypePlugin o) => IsTypePlugin o Source #
Type class for types which implement TypePlugin
.
Instances
(ManagedPtrNewtype o, IsDescendantOf TypePlugin o) => IsTypePlugin o Source # | |
Defined in GI.GObject.Interfaces.TypePlugin |
Methods
Overloaded methods
completeInterfaceInfo
typePluginCompleteInterfaceInfo Source #
Arguments
:: (HasCallStack, MonadIO m, IsTypePlugin a) | |
=> a |
|
-> GType |
|
-> GType |
|
-> InterfaceInfo |
|
-> 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 Source #
Arguments
:: (HasCallStack, MonadIO m, IsTypePlugin a) | |
=> a |
|
-> GType |
|
-> TypeInfo |
|
-> TypeValueTable |
|
-> 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
Arguments
:: (HasCallStack, MonadIO m, IsTypePlugin a) | |
=> a |
|
-> 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
Arguments
:: (HasCallStack, MonadIO m, IsTypePlugin a) | |
=> a |
|
-> 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.