cola/compat.py

   1 # pylint: disable=unused-import,redefined-builtin,undefined-variable
   2 from __future__ import absolute_import, division, print_function, unicode_literals
   3 import os
   4 import sys
   5
   6 try:
   7     import urllib2 as parse  # noqa
   8 except ImportError:
   9     # Python 3
  10     from urllib import parse  # noqa
  11
  12
  13 PY_VERSION = sys.version_info[:2]  # (2, 7)
  14 PY_VERSION_MAJOR = PY_VERSION[0]
  15 PY2 = PY_VERSION_MAJOR == 2
  16 PY3 = PY_VERSION_MAJOR >= 3
  17 PY26_PLUS = PY2 and sys.version_info[1] >= 6
  18 WIN32 = sys.platform in {'win32', 'cygwin'}
  19 ENCODING = 'utf-8'
  20
  21
  22 if PY3:
  23
  24     def bstr(x, encoding=ENCODING):
  25         return bytes(x, encoding=encoding)
  26
  27
  28 elif PY26_PLUS:
  29     bstr = bytes
  30 else:
  31     # Python <= 2.5
  32     bstr = str
  33
  34
  35 if PY3:
  36
  37     def bchr(i):
  38         return bytes([i])
  39
  40     int_types = (int,)
  41     maxsize = sys.maxsize
  42     ustr = str
  43     uchr = chr
  44 else:
  45     bchr = chr
  46     maxsize = 2 ** 31
  47     # pylint: disable=unicode-builtin
  48     ustr = unicode  # noqa
  49     # pylint: disable=unichr-builtin
  50     uchr = unichr  # noqa
  51     # pylint: disable=long-builtin
  52     int_types = (int, long)  # noqa
  53
  54 # Qt's max 32-bit signed integer range (-2147483648 to 2147483647)
  55 maxint = (2 ** 31) - 1
  56
  57
  58 def setenv(key, value):
  59     """Compatibility wrapper for setting environment variables
  60
  61     Why?  win32 requires putenv().  UNIX only requires os.environ.
  62     """
  63     if not PY3 and isinstance(value, ustr):
  64         value = value.encode(ENCODING, 'replace')
  65     os.environ[key] = value
  66     os.putenv(key, value)
  67
  68
  69 def unsetenv(key):
  70     """Compatibility wrapper for unsetting environment variables"""
  71     os.environ.pop(key, None)
  72     if hasattr(os, 'unsetenv'):
  73         os.unsetenv(key)
  74
  75
  76 def no_op(value):
  77     """Return the value as-is"""
  78     return value
  79
  80
  81 def byte_offset_to_int_converter():
  82     """Return a function to convert byte string offsets into ints
  83
  84     Indexing into python3 bytes returns ints, Python2 returns str.
  85     Thus, on Python2 we need to use `ord()` to convert the byte into
  86     an integer.  It's already an int on Python3, so we use no_op there.
  87     """
  88     if PY2:
  89         result = ord
  90     else:
  91         result = no_op
  92     return result