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* This library is free software: you can redistribute it and/or modify it
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* under the terms of the GNU Lesser General Public License as published by
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* the Free Software Foundation.
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* This library is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
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* or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License
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* You should have received a copy of the GNU Lesser General Public License
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* along with this library. If not, see <http://www.gnu.org/licenses/>.
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* SECTION: e-extensible
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* @include: libedataserver/libedataserver.h
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* @short_description: An interface for extending objects
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* #EExtension objects can be tacked on to any #GObject instance that
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* implements the #EExtensible interface. A #GObject type can be made
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* extensible in two steps:
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* 1. Add the #EExtensible interface when registering the #GType.
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* There are no methods to implement.
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* #include <libedataserver/libedataserver.h>
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* G_DEFINE_TYPE_WITH_CODE (
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* ECustomWidget, e_custom_widget, GTK_TYPE_WIDGET,
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* G_IMPLEMENT_INTERFACE (E_TYPE_EXTENSIBLE, NULL))
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* 2. Load extensions for the class at some point during #GObject
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* initialization. Generally this should be done toward the end of
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* the initialization code, so extensions get a fully initialized
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* object to work with.
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* e_custom_widget_constructed (ECustomWidget *widget)
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* Construction code goes here, same as call to parent's 'constructed'...
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* e_extensible_load_extensions (E_EXTENSIBLE (widget));
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#include "e-extension.h"
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#include "e-data-server-util.h"
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#include "e-extensible.h"
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#define IS_AN_EXTENSION_TYPE(type) \
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(g_type_is_a ((type), E_TYPE_EXTENSION))
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static GQuark extensible_quark;
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extensible_get_extensions (EExtensible *extensible)
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return g_object_get_qdata (G_OBJECT (extensible), extensible_quark);
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extensible_load_extension (GType extension_type,
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EExtensible *extensible)
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EExtensionClass *extension_class;
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GType extensible_type;
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GPtrArray *extensions;
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EExtension *extension;
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extensible_type = G_OBJECT_TYPE (extensible);
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extension_class = g_type_class_ref (extension_type);
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/* Only load extensions that extend the given extensible object. */
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if (!g_type_is_a (extensible_type, extension_class->extensible_type))
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extension = g_object_new (
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extension_type, "extensible", extensible, NULL);
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extensions = extensible_get_extensions (extensible);
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g_ptr_array_add (extensions, extension);
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g_type_class_unref (extension_class);
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e_extensible_default_init (EExtensibleInterface *iface)
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extensible_quark = g_quark_from_static_string ("e-extensible-quark");
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* e_extensible_load_extensions:
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* @extensible: an #EExtensible
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* Creates an instance of all instantiable subtypes of #EExtension which
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* target the class of @extensible. The lifetimes of these newly created
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* #EExtension objects are bound to @extensible such that they are finalized
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* when @extensible is finalized.
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e_extensible_load_extensions (EExtensible *extensible)
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GPtrArray *extensions;
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g_return_if_fail (E_IS_EXTENSIBLE (extensible));
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if (extensible_get_extensions (extensible) != NULL)
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extensions = g_ptr_array_new_with_free_func (
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(GDestroyNotify) g_object_unref);
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g_object_set_qdata_full (
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G_OBJECT (extensible), extensible_quark,
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g_ptr_array_ref (extensions),
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(GDestroyNotify) g_ptr_array_unref);
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E_TYPE_EXTENSION, (ETypeFunc)
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extensible_load_extension, extensible);
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/* If the extension array is still empty, remove it from the
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* extensible object. It may be that no extension types have
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* been registered yet, so this allows for trying again later. */
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if (extensions->len == 0)
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G_OBJECT (extensible),
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extensible_quark, NULL);
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g_ptr_array_unref (extensions);
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* e_extensible_list_extensions:
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* @extensible: an #EExtensible
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* @extension_type: the type of extensions to list
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* Returns a list of #EExtension objects bound to @extensible whose
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* types are ancestors of @extension_type. For a complete list of
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* extension objects bound to @extensible, pass %E_TYPE_EXTENSION.
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* The list itself should be freed with g_list_free(). The extension
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* objects are owned by @extensible and should not be unreferenced.
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* Returns: a list of extension objects derived from @extension_type
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e_extensible_list_extensions (EExtensible *extensible,
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GType extension_type)
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GPtrArray *extensions;
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g_return_val_if_fail (E_IS_EXTENSIBLE (extensible), NULL);
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g_return_val_if_fail (IS_AN_EXTENSION_TYPE (extension_type), NULL);
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e_extensible_load_extensions (extensible);
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extensions = extensible_get_extensions (extensible);
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/* This will be NULL if no extensions are present. */
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if (extensions == NULL)
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for (ii = 0; ii < extensions->len; ii++) {
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object = g_ptr_array_index (extensions, ii);
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if (g_type_is_a (G_OBJECT_TYPE (object), extension_type))
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list = g_list_prepend (list, object);
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return g_list_reverse (list);
added
removed
libedataserver/e-extensible.c
