diff options
Diffstat (limited to 'third_party/python/attrs/attr/_compat.py')
| -rw-r--r-- | third_party/python/attrs/attr/_compat.py | 185 |
1 files changed, 185 insertions, 0 deletions
diff --git a/third_party/python/attrs/attr/_compat.py b/third_party/python/attrs/attr/_compat.py new file mode 100644 index 0000000000..c3bf5e33ba --- /dev/null +++ b/third_party/python/attrs/attr/_compat.py @@ -0,0 +1,185 @@ +# SPDX-License-Identifier: MIT + + +import inspect +import platform +import sys +import threading +import types +import warnings + +from collections.abc import Mapping, Sequence # noqa +from typing import _GenericAlias + + +PYPY = platform.python_implementation() == "PyPy" +PY_3_9_PLUS = sys.version_info[:2] >= (3, 9) +PY310 = sys.version_info[:2] >= (3, 10) +PY_3_12_PLUS = sys.version_info[:2] >= (3, 12) + + +def just_warn(*args, **kw): + warnings.warn( + "Running interpreter doesn't sufficiently support code object " + "introspection. Some features like bare super() or accessing " + "__class__ will not work with slotted classes.", + RuntimeWarning, + stacklevel=2, + ) + + +class _AnnotationExtractor: + """ + Extract type annotations from a callable, returning None whenever there + is none. + """ + + __slots__ = ["sig"] + + def __init__(self, callable): + try: + self.sig = inspect.signature(callable) + except (ValueError, TypeError): # inspect failed + self.sig = None + + def get_first_param_type(self): + """ + Return the type annotation of the first argument if it's not empty. + """ + if not self.sig: + return None + + params = list(self.sig.parameters.values()) + if params and params[0].annotation is not inspect.Parameter.empty: + return params[0].annotation + + return None + + def get_return_type(self): + """ + Return the return type if it's not empty. + """ + if ( + self.sig + and self.sig.return_annotation is not inspect.Signature.empty + ): + return self.sig.return_annotation + + return None + + +def make_set_closure_cell(): + """Return a function of two arguments (cell, value) which sets + the value stored in the closure cell `cell` to `value`. + """ + # pypy makes this easy. (It also supports the logic below, but + # why not do the easy/fast thing?) + if PYPY: + + def set_closure_cell(cell, value): + cell.__setstate__((value,)) + + return set_closure_cell + + # Otherwise gotta do it the hard way. + + try: + if sys.version_info >= (3, 8): + + def set_closure_cell(cell, value): + cell.cell_contents = value + + else: + # Create a function that will set its first cellvar to `value`. + def set_first_cellvar_to(value): + x = value + return + + # This function will be eliminated as dead code, but + # not before its reference to `x` forces `x` to be + # represented as a closure cell rather than a local. + def force_x_to_be_a_cell(): # pragma: no cover + return x + + # Extract the code object and make sure our assumptions about + # the closure behavior are correct. + co = set_first_cellvar_to.__code__ + if co.co_cellvars != ("x",) or co.co_freevars != (): + raise AssertionError # pragma: no cover + + # Convert this code object to a code object that sets the + # function's first _freevar_ (not cellvar) to the argument. + args = [co.co_argcount] + args.append(co.co_kwonlyargcount) + args.extend( + [ + co.co_nlocals, + co.co_stacksize, + co.co_flags, + co.co_code, + co.co_consts, + co.co_names, + co.co_varnames, + co.co_filename, + co.co_name, + co.co_firstlineno, + co.co_lnotab, + # These two arguments are reversed: + co.co_cellvars, + co.co_freevars, + ] + ) + set_first_freevar_code = types.CodeType(*args) + + def set_closure_cell(cell, value): + # Create a function using the set_first_freevar_code, + # whose first closure cell is `cell`. Calling it will + # change the value of that cell. + setter = types.FunctionType( + set_first_freevar_code, {}, "setter", (), (cell,) + ) + # And call it to set the cell. + setter(value) + + # Make sure it works on this interpreter: + def make_func_with_cell(): + x = None + + def func(): + return x # pragma: no cover + + return func + + cell = make_func_with_cell().__closure__[0] + set_closure_cell(cell, 100) + if cell.cell_contents != 100: + raise AssertionError # pragma: no cover + + except Exception: + return just_warn + else: + return set_closure_cell + + +set_closure_cell = make_set_closure_cell() + +# Thread-local global to track attrs instances which are already being repr'd. +# This is needed because there is no other (thread-safe) way to pass info +# about the instances that are already being repr'd through the call stack +# in order to ensure we don't perform infinite recursion. +# +# For instance, if an instance contains a dict which contains that instance, +# we need to know that we're already repr'ing the outside instance from within +# the dict's repr() call. +# +# This lives here rather than in _make.py so that the functions in _make.py +# don't have a direct reference to the thread-local in their globals dict. +# If they have such a reference, it breaks cloudpickle. +repr_context = threading.local() + + +def get_generic_base(cl): + """If this is a generic class (A[str]), return the generic base for it.""" + if cl.__class__ is _GenericAlias: + return cl.__origin__ + return None |