[evolution-data-server] ECollectionBackend: Add default method for dup_resource_id().

[Matthew Barnes <mbarnes src gnome org>]

commit 25b692ba80a86fb7bc0be7092898a3c3f59049cd
Author: Matthew Barnes <mbarnes redhat com>
Date:   Wed Jun 27 08:27:54 2012 -0400

    ECollectionBackend: Add default method for dup_resource_id().
    
    Now checks for an E_SOURCE_EXTENSION_RESOURCE by default and returns the
    "identity" value if the extension if present.  Otherwise it returns NULL.

 libebackend/e-collection-backend.c |   20 ++++++++++++++++++++
 1 files changed, 20 insertions(+), 0 deletions(-)
---
diff --git a/libebackend/e-collection-backend.c b/libebackend/e-collection-backend.c
index 063e383..888b5a5 100644
--- a/libebackend/e-collection-backend.c
+++ b/libebackend/e-collection-backend.c
@@ -572,6 +572,25 @@ collection_backend_populate (ECollectionBackend *backend)
 	/* Placeholder so subclasses can safely chain up. */
 }
 
+static gchar *
+collection_backend_dup_resource_id (ECollectionBackend *backend,
+                                    ESource *source)
+{
+	const gchar *extension_name;
+	gchar *resource_id = NULL;
+
+	extension_name = E_SOURCE_EXTENSION_RESOURCE;
+
+	if (e_source_has_extension (source, extension_name)) {
+		ESourceResource *extension;
+
+		extension = e_source_get_extension (source, extension_name);
+		resource_id = e_source_resource_dup_identity (extension);
+	}
+
+	return resource_id;
+}
+
 static void
 collection_backend_child_added (ECollectionBackend *backend,
                                 ESource *child_source)
@@ -610,6 +629,7 @@ e_collection_backend_class_init (ECollectionBackendClass *class)
 	object_class->constructed = collection_backend_constructed;
 
 	class->populate = collection_backend_populate;
+	class->dup_resource_id = collection_backend_dup_resource_id;
 	class->child_added = collection_backend_child_added;
 	class->child_removed = collection_backend_child_removed;