python/mozterm/mozterm/terminal.py

   1 # This Source Code Form is subject to the terms of the Mozilla Public
   2 # License, v. 2.0. If a copy of the MPL was not distributed with this
   3 # file, You can obtain one at http://mozilla.org/MPL/2.0/.
   4
   5 import os
   6 import sys
   7
   8 import six
   9
  10
  11 class NullTerminal(object):
  12     """Replacement for `blessed.Terminal()` that does no formatting."""
  13
  14     number_of_colors = 0
  15     width = 0
  16     height = 0
  17
  18     def __init__(self, stream=None, **kwargs):
  19         self.stream = stream or sys.__stdout__
  20         try:
  21             self.is_a_tty = os.isatty(self.stream.fileno())
  22         except Exception:
  23             self.is_a_tty = False
  24
  25     class NullCallableString(six.text_type):
  26         """A dummy callable Unicode stolen from blessings"""
  27
  28         def __new__(cls):
  29             new = six.text_type.__new__(cls, "")
  30             return new
  31
  32         def __call__(self, *args):
  33             if len(args) != 1 or isinstance(args[0], int):
  34                 return ""
  35             return args[0]
  36
  37     def __getattr__(self, attr):
  38         return self.NullCallableString()
  39
  40
  41 def Terminal(raises=False, disable_styling=False, **kwargs):
  42     if disable_styling:
  43         return NullTerminal(**kwargs)
  44     try:
  45         import blessed
  46     except Exception:
  47         if raises:
  48             raise
  49         return NullTerminal(**kwargs)
  50     return blessed.Terminal(**kwargs)