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