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# -*- Mode: Python; py-indent-offset: 4 -*-
# vim: tabstop=4 shiftwidth=4 expandtab
#
# Copyright (C) 2005-2009 Johan Dahlin <johan@gnome.org>
# 2015 Christoph Reiter
#
# importer.py: dynamic importer for introspected libraries.
#
# This library is free software; you can redistribute it and/or
# modify it under the terms of the GNU Lesser General Public
# License as published by the Free Software Foundation; either
# version 2.1 of the License, or (at your option) any later version.
#
# This library is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
# Lesser General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public
# License along with this library; if not, write to the Free Software
# Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301
# USA
from __future__ import absolute_import
import sys
import warnings
import importlib
from contextlib import contextmanager
import gi
from ._gi import Repository, RepositoryError
from ._gi import PyGIWarning
from .module import get_introspection_module
from .overrides import load_overrides
repository = Repository.get_default()
# only for backwards compatibility
modules = {}
@contextmanager
def _check_require_version(namespace, stacklevel):
"""A context manager which tries to give helpful warnings
about missing gi.require_version() which could potentially
break code if only an older version than expected is installed
or a new version gets introduced.
::
with _check_require_version("Gtk", stacklevel):
load_namespace_and_overrides()
"""
was_loaded = repository.is_registered(namespace)
yield
if was_loaded:
# it was loaded before by another import which depended on this
# namespace or by C code like libpeas
return
if namespace in ("GLib", "GObject", "Gio"):
# part of glib (we have bigger problems if versions change there)
return
if gi.get_required_version(namespace) is not None:
# the version was forced using require_version()
return
version = repository.get_version(namespace)
warnings.warn(
"%(namespace)s was imported without specifying a version first. "
"Use gi.require_version('%(namespace)s', '%(version)s') before "
"import to ensure that the right version gets loaded."
% {"namespace": namespace, "version": version},
PyGIWarning, stacklevel=stacklevel)
def get_import_stacklevel(import_hook):
"""Returns the stacklevel value for warnings.warn() for when the warning
gets emitted by an imported module, but the warning should point at the
code doing the import.
Pass import_hook=True if the warning gets generated by an import hook
(warn() gets called in load_module(), see PEP302)
"""
py_version = sys.version_info[:2]
if py_version <= (3, 2):
# 2.7 included
return 4 if import_hook else 2
elif py_version == (3, 3):
return 8 if import_hook else 10
elif py_version == (3, 4):
return 10 if import_hook else 8
else:
# fixed again in 3.5+, see https://bugs.python.org/issue24305
return 4 if import_hook else 2
class DynamicImporter(object):
# Note: see PEP302 for the Importer Protocol implemented below.
def __init__(self, path):
self.path = path
def find_module(self, fullname, path=None):
if not fullname.startswith(self.path):
return
path, namespace = fullname.rsplit('.', 1)
if path != self.path:
return
# is_registered() is faster than enumerate_versions() and
# in the common case of a namespace getting loaded before its
# dependencies, is_registered() returns True for all dependencies.
if repository.is_registered(namespace) or \
repository.enumerate_versions(namespace):
return self
else:
raise ImportError('cannot import name %s, '
'introspection typelib not found' % namespace)
def load_module(self, fullname):
if fullname in sys.modules:
return sys.modules[fullname]
path, namespace = fullname.rsplit('.', 1)
stacklevel = get_import_stacklevel(import_hook=True)
with _check_require_version(namespace, stacklevel=stacklevel):
try:
introspection_module = get_introspection_module(namespace)
except RepositoryError as e:
raise ImportError(e)
# Import all dependencies first so their init functions
# (gdk_init, ..) in overrides get called.
# https://bugzilla.gnome.org/show_bug.cgi?id=656314
for dep in repository.get_immediate_dependencies(namespace):
importlib.import_module('gi.repository.' + dep.split("-")[0])
dynamic_module = load_overrides(introspection_module)
dynamic_module.__file__ = '<%s>' % fullname
dynamic_module.__loader__ = self
sys.modules[fullname] = dynamic_module
return dynamic_module