[evolution-data-server] EExtensible: Introduce e_extensible_reload_extensions()

[Milan Crha <mcrha src gnome org>]

commit 75cec275d70c57290c94425879297ecaf412bb22
Author: Milan Crha <mcrha redhat com>
Date:   Wed May 18 18:23:02 2022 +0200

    EExtensible: Introduce e_extensible_reload_extensions()
    
    This can be used to load new extensions after a new module being loaded
    into the process.

 src/libedataserver/e-extensible.c | 96 ++++++++++++++++++++++++++-------------
 src/libedataserver/e-extensible.h |  1 +
 2 files changed, 66 insertions(+), 31 deletions(-)
---
diff --git a/src/libedataserver/e-extensible.c b/src/libedataserver/e-extensible.c
index 61e0ff1b8..812990569 100644
--- a/src/libedataserver/e-extensible.c
+++ b/src/libedataserver/e-extensible.c
@@ -74,29 +74,31 @@ extensible_get_extensions (EExtensible *extensible)
        return g_object_get_qdata (G_OBJECT (extensible), extensible_quark);
 }
 
+typedef struct _LoadData {
+       EExtensible *extensible;
+       GPtrArray *extensions;
+       GHashTable *known_types; /* GUINT_TO_POINTER (GType) ~> NULL */
+} LoadData;
+
 static void
 extensible_load_extension (GType extension_type,
-                           EExtensible *extensible)
+                           LoadData *ld)
 {
        EExtensionClass *extension_class;
        GType extensible_type;
-       GPtrArray *extensions;
        EExtension *extension;
 
-       extensible_type = G_OBJECT_TYPE (extensible);
+       extensible_type = G_OBJECT_TYPE (ld->extensible);
        extension_class = g_type_class_ref (extension_type);
 
        /* Only load extensions that extend the given extensible object. */
-       if (!g_type_is_a (extensible_type, extension_class->extensible_type))
-               goto exit;
+       if (g_type_is_a (extensible_type, extension_class->extensible_type) &&
+           (!ld->known_types || !g_hash_table_contains (ld->known_types, GUINT_TO_POINTER 
(extension_type)))) {
+               extension = g_object_new (extension_type, "extensible", ld->extensible, NULL);
 
-       extension = g_object_new (
-               extension_type, "extensible", extensible, NULL);
-
-       extensions = extensible_get_extensions (extensible);
-       g_ptr_array_add (extensions, extension);
+               g_ptr_array_add (ld->extensions, extension);
+       }
 
-exit:
        g_type_class_unref (extension_class);
 }
 
@@ -120,34 +122,66 @@ e_extensible_default_init (EExtensibleInterface *iface)
 void
 e_extensible_load_extensions (EExtensible *extensible)
 {
-       GPtrArray *extensions;
+       g_return_if_fail (E_IS_EXTENSIBLE (extensible));
+
+       if (!extensible_get_extensions (extensible))
+               e_extensible_reload_extensions (extensible);
+}
+
+/**
+ * e_extensible_reload_extensions:
+ * @extensible: an #EExtensible
+ *
+ * Similar to e_extensible_load_extensions(), only loads newly discovered
+ * extensions again. This can help in case a new module had been loaded
+ * to the process, which provides the extensions for the @extensible.
+ *
+ * Since: 3.46
+ **/
+void
+e_extensible_reload_extensions (EExtensible *extensible)
+{
+       LoadData ld;
+       GPtrArray *known_extensions;
 
        g_return_if_fail (E_IS_EXTENSIBLE (extensible));
 
-       if (extensible_get_extensions (extensible) != NULL)
-               return;
+       ld.extensible = extensible;
+       ld.extensions = extensible_get_extensions (extensible);
+       ld.known_types = NULL;
 
-       extensions = g_ptr_array_new_with_free_func (
-               (GDestroyNotify) g_object_unref);
+       known_extensions = ld.extensions;
 
-       g_object_set_qdata_full (
-               G_OBJECT (extensible), extensible_quark,
-               g_ptr_array_ref (extensions),
-               (GDestroyNotify) g_ptr_array_unref);
+       if (known_extensions) {
+               guint ii;
 
-       e_type_traverse (
-               E_TYPE_EXTENSION, (ETypeFunc)
-               extensible_load_extension, extensible);
+               g_ptr_array_ref (ld.extensions);
 
-       /* If the extension array is still empty, remove it from the
-        * extensible object.  It may be that no extension types have
-        * been registered yet, so this allows for trying again later. */
-       if (extensions->len == 0)
-               g_object_set_qdata (
-                       G_OBJECT (extensible),
-                       extensible_quark, NULL);
+               ld.known_types = g_hash_table_new (NULL, NULL);
+
+               for (ii = 0; ii < known_extensions->len; ii++) {
+                       EExtension *extension = g_ptr_array_index (known_extensions, ii);
+                       GType extension_type = G_OBJECT_TYPE (extension);
+
+                       g_hash_table_add (ld.known_types, GUINT_TO_POINTER (extension_type));
+               }
+       } else {
+               ld.extensions = g_ptr_array_new_with_free_func (g_object_unref);
+       }
+
+       e_type_traverse (E_TYPE_EXTENSION, (ETypeFunc) extensible_load_extension, &ld);
+
+       /* It may be that no extension types have been registered yet, so not
+        * setting the empty extensions allows to try again later. */
+       if (!known_extensions && ld.extensions->len > 0) {
+               g_object_set_qdata_full (
+                       G_OBJECT (extensible), extensible_quark,
+                       g_ptr_array_ref (ld.extensions),
+                       (GDestroyNotify) g_ptr_array_unref);
+       }
 
-       g_ptr_array_unref (extensions);
+       g_ptr_array_unref (ld.extensions);
+       g_clear_pointer (&ld.known_types, g_hash_table_destroy);
 }
 
 /**
diff --git a/src/libedataserver/e-extensible.h b/src/libedataserver/e-extensible.h
index 383d89a7a..f2b01f017 100644
--- a/src/libedataserver/e-extensible.h
+++ b/src/libedataserver/e-extensible.h
@@ -54,6 +54,7 @@ struct _EExtensibleInterface {
 
 GType          e_extensible_get_type           (void) G_GNUC_CONST;
 void           e_extensible_load_extensions    (EExtensible *extensible);
+void           e_extensible_reload_extensions  (EExtensible *extensible);
 GList *                e_extensible_list_extensions    (EExtensible *extensible,
                                                 GType extension_type);