Package ch.bailu.gtk.gobject

Class TypePlugin

java.lang.Object
ch.bailu.gtk.type.Type
ch.bailu.gtk.type.Pointer
ch.bailu.gtk.gobject.Object
ch.bailu.gtk.type.Interface
ch.bailu.gtk.gobject.TypePlugin
All Implemented Interfaces:
PointerInterface
public class TypePlugin extends Interface
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: 
<!-- language="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
g_type_class_ref() or through g_type_create_instance() (this is
being called by g_object_new()) 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 g_type_plugin_use() and g_type_plugin_complete_type_info()
on @new_type_plugin.

4. At some point the type's implementation isn't required anymore,
e.g. after g_type_class_unref() or g_type_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 g_type_plugin_complete_type_info() and then it calls
g_type_plugin_unuse() 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
g_type_plugin_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
g_type_plugin_use() and g_type_plugin_complete_type_info() again
when the type is needed again.

#GTypeModule 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.

https://docs.gtk.org/gobject/iface.TypePlugin.html

  • Constructor Details

  • Method Details

    • getClassHandler

      public static ClassHandler getClassHandler()

    • completeInterfaceInfo

      public void completeInterfaceInfo(long instance_type, long interface_type, @Nonnull InterfaceInfo info)
      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 #GType of an instantiatable type to which the interface is added
      interface_type - the #GType of the interface whose info is completed
      info - the #GInterfaceInfo to fill in

    • completeTypeInfo

      public void completeTypeInfo(long g_type, @Nonnull TypeInfo info, @Nonnull TypeValueTable value_table)
      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 #GType whose info is completed
      info - the #GTypeInfo struct to fill in
      value_table - the #GTypeValueTable to fill in

    • unuse

      public void unuse()
      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

      public void use()
      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.

    • getTypeID

      public static long getTypeID()

    • getParentTypeID

      public static long getParentTypeID()

    • getTypeSize

      public static TypeSystem.TypeSize getTypeSize()

    • getParentTypeSize

      public static TypeSystem.TypeSize getParentTypeSize()

    • getInstanceSize

      public static int getInstanceSize()