1 files changed, 29 insertions, 1 deletions
diff --git a/gi/__init__.py b/gi/__init__.py
index fb711c38..314d5797 100644
--- a/gi/__init__.py
+++ b/gi/__init__.py
@@ -20,8 +20,36 @@
 
 from __future__ import absolute_import
 
-from ._gi import _API
+from ._gi import _API, Repository
 
 # Force loading the GObject typelib so we have available the wrappers for
 # base classes such as GInitiallyUnowned
 from gi.repository import GObject
+
+_versions = {}
+
+def require_version(namespace, version):
+    repository = Repository.get_default()
+
+    if namespace in repository.get_loaded_namespaces():
+        loaded_version = repository.get_version(namespace)
+        if loaded_version != version:
+            raise ValueError('Namespace %s is already loaded with version %s' % \
+                             (namespace, loaded_version))
+
+    if namespace in _versions and _versions[namespace] != version:
+        raise ValueError('Namespace %s already requires version %s' % \
+                         (namespace, _versions[namespace]))
+
+    available_versions = repository.enumerate_versions(namespace)
+    if not available_versions:
+        raise ValueError('Namespace %s not available' % namespace)
+
+    if version not in available_versions:
+        raise ValueError('Namespace %s not available for version %s' % \
+                         (namespace, version))
+
+    _versions[namespace] = version
+
+def get_required_version(namespace):
+    return _versions.get(namespace, None)