1
# Copyright (C) 2010 Canonical Ltd
3
# This program is free software; you can redistribute it and/or modify
4
# it under the terms of the GNU General Public License as published by
5
# the Free Software Foundation; either version 2 of the License, or
6
# (at your option) any later version.
8
# This program is distributed in the hope that it will be useful,
9
# but WITHOUT ANY WARRANTY; without even the implied warranty of
10
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
11
# GNU General Public License for more details.
13
# You should have received a copy of the GNU General Public License
14
# along with this program; if not, write to the Free Software
15
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
17
"""Some convenience functions for general Python, such as a wrapper around
25
def get_named_object(module_name, member_name=None):
26
"""Get the Python object named by a given module and member name.
28
This is usually much more convenient than dealing with ``__import__``
31
:param module_name: a module name, as found in sys.module. It may contain
32
dots. e.g. 'sys' or 'os.path'.
33
:param member_name: (optional) a name of an attribute in that module to
34
return. It may contain dots. e.g. 'MyClass.some_method'. If not
35
given, the named module will be returned instead.
36
:raises: ImportError or AttributeError.
38
# We may have just a module name, or a module name and a member name,
39
# and either may contain dots. __import__'s return value is a bit
40
# unintuitive, so we need to take care to always return the object
41
# specified by the full combination of module name + member name.
43
# Give __import__ a from_list. It will return the last module in
44
# the dotted module name.
45
attr_chain = member_name.split('.')
46
from_list = attr_chain[:1]
47
obj = __import__(module_name, {}, {}, from_list)
48
for attr in attr_chain:
49
obj = getattr(obj, attr)
51
# We're just importing a module, no attributes, so we have no
52
# from_list. __import__ will return the first module in the dotted
53
# module name, so we look up the module from sys.modules.
54
__import__(module_name, globals(), locals(), [])
55
obj = sys.modules[module_name]
59
def calc_parent_name(module_name, member_name=None):
60
"""Determine the 'parent' of a given dotted module name and (optional)
65
>>> parent_mod, parent_member, final_attr = calc_parent_name(
66
... module_name, member_name)
67
>>> parent_obj = get_named_object(parent_mod, parent_member)
69
The idea is that ``getattr(parent_obj, final_attr)`` will equal
70
get_named_object(module_name, member_name).
72
:return: (module_name, member_name, final_attr) tuple.
74
if member_name is not None:
75
split_name = member_name.rsplit('.', 1)
76
if len(split_name) == 1:
77
return (module_name, None, member_name)
79
return (module_name, split_name[0], split_name[1])
81
split_name = module_name.rsplit('.', 1)
82
if len(split_name) == 1:
84
'No parent object for top-level module %r' % (module_name,))
86
return (split_name[0], None, split_name[1])
added
removed
bzrlib/pyutils.py
