attrsettr.py 2.6 KB

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  1. """Mixin for mapping set/getattr to self.set/get"""
  2. # Copyright (C) PyZMQ Developers
  3. # Distributed under the terms of the Modified BSD License.
  4. from __future__ import annotations
  5. import errno
  6. from typing import TypeVar, Union
  7. from .. import constants
  8. T = TypeVar("T")
  9. OptValT = Union[str, bytes, int]
  10. class AttributeSetter:
  11. def __setattr__(self, key: str, value: OptValT) -> None:
  12. """set zmq options by attribute"""
  13. if key in self.__dict__:
  14. object.__setattr__(self, key, value)
  15. return
  16. # regular setattr only allowed for class-defined attributes
  17. for cls in self.__class__.mro():
  18. if key in cls.__dict__ or key in getattr(cls, "__annotations__", {}):
  19. object.__setattr__(self, key, value)
  20. return
  21. upper_key = key.upper()
  22. try:
  23. opt = getattr(constants, upper_key)
  24. except AttributeError:
  25. raise AttributeError(
  26. f"{self.__class__.__name__} has no such option: {upper_key}"
  27. )
  28. else:
  29. self._set_attr_opt(upper_key, opt, value)
  30. def _set_attr_opt(self, name: str, opt: int, value: OptValT) -> None:
  31. """override if setattr should do something other than call self.set"""
  32. self.set(opt, value)
  33. def __getattr__(self, key: str) -> OptValT:
  34. """get zmq options by attribute"""
  35. upper_key = key.upper()
  36. try:
  37. opt = getattr(constants, upper_key)
  38. except AttributeError:
  39. raise AttributeError(
  40. f"{self.__class__.__name__} has no such option: {upper_key}"
  41. ) from None
  42. else:
  43. from zmq import ZMQError
  44. try:
  45. return self._get_attr_opt(upper_key, opt)
  46. except ZMQError as e:
  47. # EINVAL will be raised on access for write-only attributes.
  48. # Turn that into an AttributeError
  49. # necessary for mocking
  50. if e.errno in {errno.EINVAL, errno.EFAULT}:
  51. raise AttributeError(f"{key} attribute is write-only")
  52. else:
  53. raise
  54. def _get_attr_opt(self, name, opt) -> OptValT:
  55. """override if getattr should do something other than call self.get"""
  56. return self.get(opt)
  57. def get(self, opt: int) -> OptValT:
  58. """Override in subclass"""
  59. raise NotImplementedError("override in subclass")
  60. def set(self, opt: int, val: OptValT) -> None:
  61. """Override in subclass"""
  62. raise NotImplementedError("override in subclass")
  63. __all__ = ['AttributeSetter']