girepository: Add length ‘out’ arguments to several getter methods

This makes them consistent with the other getter methods in
`GIRepository` which return lists/arrays. It’s useful to return the
length, as that means the caller doesn’t have to work it out by
iterating over the entire array.

Signed-off-by: Philip Withnall <pwithnall@gnome.org>

Helps: #3155

docs/reference/girepository/migrating-gi.md

@@ -64,6 +64,7 @@ your code if integer type warnings are enabled.
 | `g_irepository_get_default` | Singleton object removed; create separate [class@GIRepository.Repository] instances instead |
 | `g_irepository_get_search_path` and `g_irepository_get_library_path` | Now return arrays rather than linked lists |
 | `g_irepository_enumerate_versions` | Now returns an array rather than a linked list |
+| `g_irepository_get_immediate_dependencies`, `g_irepository_get_dependencies` and `g_irepository_get_loaded_namespaces` | Now additionally return a length argument |
 | `g_irepository_dump` | Takes structured `input_filename` and `output_filename` arguments rather than a single formatted string |
 | `g_function_invoker_destroy` | `gi_function_invoker_clear()` |
 | `g_struct_info_get_copy_function` | [method@GIRepository.StructInfo.get_copy_function_name] |

girepository/girepository.c

@@ -547,6 +547,8 @@ register_internal (GIRepository *repository,
  * gi_repository_get_immediate_dependencies:
  * @repository: A #GIRepository
  * @namespace_: Namespace of interest
+ * @n_dependencies_out: (optional) (out): Return location for the number of
+ *   dependencies
  *
  * Return an array of the immediate versioned dependencies for @namespace_.
  * Returned strings are of the form `namespace-version`.
@@ -558,13 +560,17 @@ register_internal (GIRepository *repository,
  * To get the transitive closure of dependencies for @namespace_, use
  * [method@GIRepository.Repository.get_dependencies].
  *
- * Returns: (transfer full) (array zero-terminated=1): `NULL`-terminated string
+ * The list is guaranteed to be `NULL` terminated. The `NULL` terminator is not
- *   array of immediate versioned dependencies
+ * counted in @n_dependencies_out.
+ *
+ * Returns: (transfer full) (array length=n_dependencies_out): String array of
+ *   immediate versioned dependencies
  * Since: 2.80
  */
 char **
 gi_repository_get_immediate_dependencies (GIRepository *repository,
-                                          const char   *namespace)
+                                          const char   *namespace,
+                                          size_t       *n_dependencies_out)
 {
   GITypelib *typelib;
   char **deps;
@@ -580,6 +586,9 @@ gi_repository_get_immediate_dependencies (GIRepository *repository,
   if (deps == NULL)
       deps = g_strsplit ("", "|", 0);
 
+  if (n_dependencies_out != NULL)
+    *n_dependencies_out = g_strv_length (deps);
+
   return deps;
 }
 
@@ -627,6 +636,8 @@ get_typelib_dependencies_transitive (GIRepository *repository,
  * gi_repository_get_dependencies:
  * @repository: A #GIRepository
  * @namespace_: Namespace of interest
+ * @n_dependencies_out: (optional) (out): Return location for the number of
+ *   dependencies
  *
  * Retrieves all (transitive) versioned dependencies for
  * @namespace_.
@@ -640,13 +651,17 @@ get_typelib_dependencies_transitive (GIRepository *repository,
  * To get only the immediate dependencies for @namespace_, use
  * [method@GIRepository.Repository.get_immediate_dependencies].
  *
- * Returns: (transfer full) (array zero-terminated=1): `NULL`-terminated string
+ * The list is guaranteed to be `NULL` terminated. The `NULL` terminator is not
- *   array of all versioned dependencies
+ * counted in @n_dependencies_out.
+ *
+ * Returns: (transfer full) (array length=n_dependencies_out): String array of
+ *   all versioned dependencies
  * Since: 2.80
  */
 char **
 gi_repository_get_dependencies (GIRepository *repository,
-                                const char *namespace)
+                                const char   *namespace,
+                                size_t       *n_dependencies_out)
 {
   GITypelib *typelib;
   GHashTable *transitive_dependencies;  /* set of owned utf8 */
@@ -679,6 +694,9 @@ gi_repository_get_dependencies (GIRepository *repository,
 
   g_hash_table_unref (transitive_dependencies);
 
+  if (n_dependencies_out != NULL)
+    *n_dependencies_out = out->len;
+
   return (char **) g_ptr_array_free (out, FALSE);
 }
 
@@ -1166,15 +1184,21 @@ collect_namespaces (gpointer key,
 /**
  * gi_repository_get_loaded_namespaces:
  * @repository: A #GIRepository
+ * @n_namespaces_out: (optional) (out): Return location for the number of
+ *   namespaces
  *
  * Return the list of currently loaded namespaces.
  *
- * Returns: (element-type utf8) (transfer full) (array zero-terminated=1): `NULL`-terminated
+ * The list is guaranteed to be `NULL` terminated. The `NULL` terminator is not
+ * counted in @n_namespaces_out.
+ *
+ * Returns: (element-type utf8) (transfer full) (array length=n_namespaces_out):
  *   list of namespaces
  * Since: 2.80
  */
 char **
-gi_repository_get_loaded_namespaces (GIRepository *repository)
+gi_repository_get_loaded_namespaces (GIRepository *repository,
+                                     size_t       *n_namespaces_out)
 {
   GList *l, *list = NULL;
   char **names;
@@ -1191,6 +1215,9 @@ gi_repository_get_loaded_namespaces (GIRepository *repository)
     names[i++] = g_strdup (l->data);
   g_list_free (list);
 
+  if (n_namespaces_out != NULL)
+    *n_namespaces_out = i;
+
   return names;
 }
 

girepository/girepository.h

@@ -133,14 +133,17 @@ GITypelib *    gi_repository_require_private (GIRepository           *repository
 
 GI_AVAILABLE_IN_ALL
 char       ** gi_repository_get_immediate_dependencies (GIRepository *repository,
-                                                        const char   *namespace_);
+                                                        const char   *namespace_,
+                                                        size_t       *n_dependencies_out);
 
 GI_AVAILABLE_IN_ALL
 char       ** gi_repository_get_dependencies (GIRepository *repository,
-                                              const char   *namespace_);
+                                              const char   *namespace_,
+                                              size_t       *n_dependencies_out);
 
 GI_AVAILABLE_IN_ALL
-char       ** gi_repository_get_loaded_namespaces (GIRepository *repository);
+char       ** gi_repository_get_loaded_namespaces (GIRepository *repository,
+                                                   size_t       *n_namespaces_out);
 
 GI_AVAILABLE_IN_ALL
 GIBaseInfo *  gi_repository_find_by_gtype (GIRepository *repository,

girepository/girwriter.c

@@ -1373,7 +1373,7 @@ gi_ir_writer_write (const char *filename,
               "            xmlns:c=\"http://www.gtk.org/introspection/c/1.0\"\n"
               "            xmlns:glib=\"http://www.gtk.org/introspection/glib/1.0\"");
 
-  dependencies = gi_repository_get_immediate_dependencies (repository, ns);
+  dependencies = gi_repository_get_immediate_dependencies (repository, ns, NULL);
   if (dependencies != NULL)
     {
       for (i = 0; dependencies[i]; i++)

girepository/tests/repository.c

@@ -41,6 +41,7 @@ test_repository_basic (RepositoryFixture *fx,
 {
   const char * const * search_paths;
   char **namespaces = NULL;
+  size_t n_namespaces;
   const char *expected_namespaces[] = { "GLib", NULL };
   char **versions;
   size_t n_versions;
@@ -64,8 +65,9 @@ test_repository_basic (RepositoryFixture *fx,
   g_assert_cmpuint (g_strv_length ((char **) search_paths), >, 0);
   g_assert_cmpstr (search_paths[0], ==, fx->gobject_typelib_dir);
 
-  namespaces = gi_repository_get_loaded_namespaces (fx->repository);
+  namespaces = gi_repository_get_loaded_namespaces (fx->repository, &n_namespaces);
   g_assert_cmpstrv (namespaces, expected_namespaces);
+  g_assert_cmpuint (n_namespaces, ==, g_strv_length ((char **) expected_namespaces));
   g_strfreev (namespaces);
 
   prefix = gi_repository_get_c_prefix (fx->repository, "GLib");
@@ -142,11 +144,13 @@ test_repository_dependencies (RepositoryFixture *fx,
 {
   GError *error = NULL;
   char **dependencies;
+  size_t n_dependencies;
 
   g_test_summary ("Test ensures namespace dependencies are correctly exposed");
 
-  dependencies = gi_repository_get_dependencies (fx->repository, "GObject");
+  dependencies = gi_repository_get_dependencies (fx->repository, "GObject", &n_dependencies);
   g_assert_cmpuint (g_strv_length (dependencies), ==, 1);
+  g_assert_cmpuint (n_dependencies, ==, 1);
   g_assert_true (g_strv_contains ((const char **) dependencies, "GLib-2.0"));
 
   g_clear_error (&error);