cola/compat.py

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