Source Code for Package tdi.c

 1  # -*- coding: ascii -*- 
 2  r""" 
 3  :Copyright: 
 4   
 5   Copyright 2006 - 2015 
 6   Andr\xe9 Malo or his licensors, as applicable 
 7   
 8  :License: 
 9   
10   Licensed under the Apache License, Version 2.0 (the "License"); 
11   you may not use this file except in compliance with the License. 
12   You may obtain a copy of the License at 
13   
14       http://www.apache.org/licenses/LICENSE-2.0 
15   
16   Unless required by applicable law or agreed to in writing, software 
17   distributed under the License is distributed on an "AS IS" BASIS, 
18   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 
19   See the License for the specific language governing permissions and 
20   limitations under the License. 
21   
22  ========================== 
23   Modules implemented in C 
24  ========================== 
25   
26  The modules in this package implement (or reimplement) various functionality 
27  in C for reasons of performance or availability. The performance 
28  implementations are always re-implementations of accompanying python 
29  functions. 
30   
31  The standard way to import these modules is to use the `load` function. It 
32  catches ImportError and disabled C overrides via environment. 
33  """ 
34  if __doc__: 
35      # pylint: disable = redefined-builtin 
36      __doc__ = __doc__.encode('ascii').decode('unicode_escape') 
37  __author__ = r"Andr\xe9 Malo".encode('ascii').decode('unicode_escape') 
38  __docformat__ = "restructuredtext en" 
39   
40  import os as _os 
41   
42  #: Default environment variable name 
43  #: 
44  #: This variable can be set to ``1`` in order to disable loading of tdi's c 
45  #: extensions 
46  #: 
47  #: :Type: ``str`` 
48  DEFAULT_ENV_OVERRIDE = 'TDI_NO_C_OVERRIDE' 
49   
50  #: Default template for the fully qualified module name 
51  #: 
52  #: :Type: ``str`` 
53  DEFAULT_TPL = 'tdi.c._tdi_%s' 
54   
55   
56 -def load(modname, env_override=None, tpl=None): 
57      """ 
58      Module loading facade 
59   
60      :Parameters: 
61        `modname` : ``str`` 
62          Module name part (like ``util`` for ``tdi.c._tdi_util``), see `tpl` 
63   
64        `env_override` : ``str`` 
65          Name of the environment variable, which can disable the c extension 
66          import if set to ``1``. If omitted or ``None``, 
67          `DEFAULT_ENV_OVERRIDE` is applied. 
68   
69        `tpl` : ``str`` 
70          Template for the fully qualified module name. It has to contain one 
71          %s format specifier which takes the `modname` part. If omitted or 
72          ``None``, `DEFAULT_TPL` is applied. 
73   
74      :Return: The requested module or ``None`` (either by env request or 
75               ``ImportError``) 
76      :Rtype: ``module`` 
77      """ 
78      if env_override is None: 
79          env_override = DEFAULT_ENV_OVERRIDE 
80      if _os.environ.get(env_override) != '1': 
81          if tpl is None: 
82              tpl = DEFAULT_TPL 
83          try: 
84              mod = __import__(tpl % modname, globals(), locals(), ['*']) 
85          except ImportError: 
86              mod = None 
87      else: 
88          mod = None 
89      return mod 
90