Add e_collection_backend_dup_resource_id().

Extracts the resource ID for a child source, which is supposed to be a
stable and unique server-assigned identifier for the remote resource
described by the child source.  If the child source is not actually a
child of the collection backend, the function returns NULL.

diff --git a/docs/reference/libebackend/libebackend-sections.txt b/docs/reference/libebackend/libebackend-sections.txt
index 269651e..8337e13 100644 (file)
--- a/docs/reference/libebackend/libebackend-sections.txt
+++ b/docs/reference/libebackend/libebackend-sections.txt
@@ -118,6 +118,7 @@ ECollectionBackend
 e_collection_backend_new_child
 e_collection_backend_ref_server
 e_collection_backend_get_cache_dir
+e_collection_backend_dup_resource_id
 e_collection_backend_claim_all_resources
 e_collection_backend_list_calendar_sources
 e_collection_backend_list_contacts_sources

diff --git a/libebackend/e-collection-backend.c b/libebackend/e-collection-backend.c
index e6a280c..cfb75ea 100644 (file)
--- a/libebackend/e-collection-backend.c
+++ b/libebackend/e-collection-backend.c
@@ -1020,6 +1020,58 @@ e_collection_backend_get_cache_dir (ECollectionBackend *backend)
 }
 
 /**
+ * e_collection_backend_dup_resource_id:
+ * @backend: an #ECollectionBackend
+ * @child_source: an #ESource managed by @backend
+ *
+ * Extracts the resource ID for @child_source, which is supposed to be a
+ * stable and unique server-assigned identifier for the remote resource
+ * described by @child_source.  If @child_source is not actually a child
+ * of the collection #EBackend:source owned by @backend, the function
+ * returns %NULL.
+ *
+ * The returned string should be freed with g_free() when no longer needed.
+ *
+ * Returns: a newly-allocated resource ID for @child_source, or %NULL
+ *
+ * Since: 3.6
+ **/
+gchar *
+e_collection_backend_dup_resource_id (ECollectionBackend *backend,
+                                      ESource *child_source)
+{
+       ECollectionBackend *backend_for_child_source;
+       ECollectionBackendClass *class;
+       ESourceRegistryServer *server;
+       gboolean child_is_ours = FALSE;
+
+       g_return_val_if_fail (E_IS_COLLECTION_BACKEND (backend), NULL);
+       g_return_val_if_fail (E_IS_SOURCE (child_source), NULL);
+
+       class = E_COLLECTION_BACKEND_GET_CLASS (backend);
+       g_return_val_if_fail (class->dup_resource_id != NULL, NULL);
+
+       /* Make sure the ESource belongs to the ECollectionBackend to
+        * avoid accidentally creating a new extension while trying to
+        * extract a resource ID that isn't there.  Better to test this
+        * up front than rely on ECollectionBackend subclasses to do it. */
+       server = e_collection_backend_ref_server (backend);
+       backend_for_child_source =
+               e_source_registry_server_ref_backend (server, child_source);
+       g_object_unref (server);
+
+       if (backend_for_child_source != NULL) {
+               child_is_ours = (backend_for_child_source == backend);
+               g_object_unref (backend_for_child_source);
+       }
+
+       if (!child_is_ours)
+               return NULL;
+
+       return class->dup_resource_id (backend, child_source);
+}
+
+/**
  * e_collection_backend_claim_all_resources:
  * @backend: an #ECollectionBackend
  *

diff --git a/libebackend/e-collection-backend.h b/libebackend/e-collection-backend.h
index 8f97691..1ebcd7f 100644 (file)
--- a/libebackend/e-collection-backend.h
+++ b/libebackend/e-collection-backend.h
@@ -117,6 +117,9 @@ struct _ESourceRegistryServer *
                e_collection_backend_ref_server (ECollectionBackend *backend);
 const gchar *  e_collection_backend_get_cache_dir
                                                (ECollectionBackend *backend);
+gchar *                e_collection_backend_dup_resource_id
+                                               (ECollectionBackend *backend,
+                                                ESource *child_source);
 GList *                e_collection_backend_claim_all_resources
                                                (ECollectionBackend *backend);
 GList *                e_collection_backend_list_calendar_sources