1 files changed, 70 insertions, 0 deletions
diff --git a/hypervideo_dl/compat/compat_utils.py b/hypervideo_dl/compat/compat_utils.py
new file mode 100644
index 0000000..1bf6566
--- /dev/null
+++ b/hypervideo_dl/compat/compat_utils.py
@@ -0,0 +1,70 @@
+import collections
+import contextlib
+import importlib
+import sys
+import types
+
+_NO_ATTRIBUTE = object()
+
+_Package = collections.namedtuple('Package', ('name', 'version'))
+
+
+def get_package_info(module):
+    parent = module.__name__.split('.')[0]
+    parent_module = None
+    with contextlib.suppress(ImportError):
+        parent_module = importlib.import_module(parent)
+
+    for attr in ('__version__', 'version_string', 'version'):
+        version = getattr(parent_module, attr, None)
+        if version is not None:
+            break
+    return _Package(getattr(module, '_hypervideo_dl__identifier', parent), str(version))
+
+
+def _is_package(module):
+    try:
+        module.__getattribute__('__path__')
+    except AttributeError:
+        return False
+    return True
+
+
+def passthrough_module(parent, child, allowed_attributes=None, *, callback=lambda _: None):
+    parent_module = importlib.import_module(parent)
+    child_module = None  # Import child module only as needed
+
+    class PassthroughModule(types.ModuleType):
+        def __getattr__(self, attr):
+            if _is_package(parent_module):
+                with contextlib.suppress(ImportError):
+                    return importlib.import_module(f'.{attr}', parent)
+
+            ret = self.__from_child(attr)
+            if ret is _NO_ATTRIBUTE:
+                raise AttributeError(f'module {parent} has no attribute {attr}')
+            callback(attr)
+            return ret
+
+        def __from_child(self, attr):
+            if allowed_attributes is None:
+                if attr.startswith('__') and attr.endswith('__'):
+                    return _NO_ATTRIBUTE
+            elif attr not in allowed_attributes:
+                return _NO_ATTRIBUTE
+
+            nonlocal child_module
+            child_module = child_module or importlib.import_module(child, parent)
+
+            with contextlib.suppress(AttributeError):
+                return getattr(child_module, attr)
+
+            if _is_package(child_module):
+                with contextlib.suppress(ImportError):
+                    return importlib.import_module(f'.{attr}', child)
+
+            return _NO_ATTRIBUTE
+
+    # Python 3.6 does not have module level __getattr__
+    # https://peps.python.org/pep-0562/
+    sys.modules[parent].__class__ = PassthroughModule