venv/lib/python3.11/site-packages/setuptools/_vendor/importlib_metadata/_adapters.py

   1 import functools
   2 import warnings
   3 import re
   4 import textwrap
   5 import email.message
   6
   7 from ._text import FoldedCase
   8 from ._compat import pypy_partial
   9
  10
  11 # Do not remove prior to 2024-01-01 or Python 3.14
  12 _warn = functools.partial(
  13     warnings.warn,
  14     "Implicit None on return values is deprecated and will raise KeyErrors.",
  15     DeprecationWarning,
  16     stacklevel=pypy_partial(2),
  17 )
  18
  19
  20 class Message(email.message.Message):
  21     multiple_use_keys = set(
  22         map(
  23             FoldedCase,
  24             [
  25                 'Classifier',
  26                 'Obsoletes-Dist',
  27                 'Platform',
  28                 'Project-URL',
  29                 'Provides-Dist',
  30                 'Provides-Extra',
  31                 'Requires-Dist',
  32                 'Requires-External',
  33                 'Supported-Platform',
  34                 'Dynamic',
  35             ],
  36         )
  37     )
  38     """
  39     Keys that may be indicated multiple times per PEP 566.
  40     """
  41
  42     def __new__(cls, orig: email.message.Message):
  43         res = super().__new__(cls)
  44         vars(res).update(vars(orig))
  45         return res
  46
  47     def __init__(self, *args, **kwargs):
  48         self._headers = self._repair_headers()
  49
  50     # suppress spurious error from mypy
  51     def __iter__(self):
  52         return super().__iter__()
  53
  54     def __getitem__(self, item):
  55         """
  56         Warn users that a ``KeyError`` can be expected when a
  57         mising key is supplied. Ref python/importlib_metadata#371.
  58         """
  59         res = super().__getitem__(item)
  60         if res is None:
  61             _warn()
  62         return res
  63
  64     def _repair_headers(self):
  65         def redent(value):
  66             "Correct for RFC822 indentation"
  67             if not value or '\n' not in value:
  68                 return value
  69             return textwrap.dedent(' ' * 8 + value)
  70
  71         headers = [(key, redent(value)) for key, value in vars(self)['_headers']]
  72         if self._payload:
  73             headers.append(('Description', self.get_payload()))
  74         return headers
  75
  76     @property
  77     def json(self):
  78         """
  79         Convert PackageMetadata to a JSON-compatible format
  80         per PEP 0566.
  81         """
  82
  83         def transform(key):
  84             value = self.get_all(key) if key in self.multiple_use_keys else self[key]
  85             if key == 'Keywords':
  86                 value = re.split(r'\s+', value)
  87             tk = key.lower().replace('-', '_')
  88             return tk, value
  89
  90         return dict(map(transform, map(FoldedCase, self)))