186 lines
5.4 KiB
Python
186 lines
5.4 KiB
Python
# SPDX-License-Identifier: MIT
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import inspect
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import platform
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import sys
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import threading
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import types
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import warnings
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from collections.abc import Mapping, Sequence # noqa
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PYPY = platform.python_implementation() == "PyPy"
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PY36 = sys.version_info[:2] >= (3, 6)
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HAS_F_STRINGS = PY36
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PY310 = sys.version_info[:2] >= (3, 10)
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if PYPY or PY36:
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ordered_dict = dict
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else:
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from collections import OrderedDict
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ordered_dict = OrderedDict
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def just_warn(*args, **kw):
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warnings.warn(
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"Running interpreter doesn't sufficiently support code object "
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"introspection. Some features like bare super() or accessing "
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"__class__ will not work with slotted classes.",
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RuntimeWarning,
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stacklevel=2,
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)
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class _AnnotationExtractor:
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"""
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Extract type annotations from a callable, returning None whenever there
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is none.
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"""
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__slots__ = ["sig"]
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def __init__(self, callable):
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try:
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self.sig = inspect.signature(callable)
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except (ValueError, TypeError): # inspect failed
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self.sig = None
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def get_first_param_type(self):
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"""
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Return the type annotation of the first argument if it's not empty.
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"""
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if not self.sig:
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return None
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params = list(self.sig.parameters.values())
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if params and params[0].annotation is not inspect.Parameter.empty:
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return params[0].annotation
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return None
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def get_return_type(self):
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"""
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Return the return type if it's not empty.
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"""
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if (
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self.sig
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and self.sig.return_annotation is not inspect.Signature.empty
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):
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return self.sig.return_annotation
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return None
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def make_set_closure_cell():
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"""Return a function of two arguments (cell, value) which sets
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the value stored in the closure cell `cell` to `value`.
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"""
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# pypy makes this easy. (It also supports the logic below, but
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# why not do the easy/fast thing?)
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if PYPY:
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def set_closure_cell(cell, value):
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cell.__setstate__((value,))
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return set_closure_cell
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# Otherwise gotta do it the hard way.
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# Create a function that will set its first cellvar to `value`.
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def set_first_cellvar_to(value):
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x = value
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return
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# This function will be eliminated as dead code, but
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# not before its reference to `x` forces `x` to be
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# represented as a closure cell rather than a local.
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def force_x_to_be_a_cell(): # pragma: no cover
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return x
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try:
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# Extract the code object and make sure our assumptions about
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# the closure behavior are correct.
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co = set_first_cellvar_to.__code__
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if co.co_cellvars != ("x",) or co.co_freevars != ():
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raise AssertionError # pragma: no cover
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# Convert this code object to a code object that sets the
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# function's first _freevar_ (not cellvar) to the argument.
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if sys.version_info >= (3, 8):
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def set_closure_cell(cell, value):
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cell.cell_contents = value
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else:
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args = [co.co_argcount]
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args.append(co.co_kwonlyargcount)
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args.extend(
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[
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co.co_nlocals,
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co.co_stacksize,
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co.co_flags,
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co.co_code,
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co.co_consts,
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co.co_names,
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co.co_varnames,
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co.co_filename,
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co.co_name,
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co.co_firstlineno,
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co.co_lnotab,
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# These two arguments are reversed:
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co.co_cellvars,
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co.co_freevars,
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]
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)
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set_first_freevar_code = types.CodeType(*args)
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def set_closure_cell(cell, value):
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# Create a function using the set_first_freevar_code,
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# whose first closure cell is `cell`. Calling it will
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# change the value of that cell.
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setter = types.FunctionType(
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set_first_freevar_code, {}, "setter", (), (cell,)
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)
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# And call it to set the cell.
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setter(value)
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# Make sure it works on this interpreter:
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def make_func_with_cell():
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x = None
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def func():
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return x # pragma: no cover
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return func
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cell = make_func_with_cell().__closure__[0]
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set_closure_cell(cell, 100)
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if cell.cell_contents != 100:
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raise AssertionError # pragma: no cover
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except Exception:
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return just_warn
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else:
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return set_closure_cell
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set_closure_cell = make_set_closure_cell()
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# Thread-local global to track attrs instances which are already being repr'd.
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# This is needed because there is no other (thread-safe) way to pass info
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# about the instances that are already being repr'd through the call stack
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# in order to ensure we don't perform infinite recursion.
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#
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# For instance, if an instance contains a dict which contains that instance,
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# we need to know that we're already repr'ing the outside instance from within
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# the dict's repr() call.
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#
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# This lives here rather than in _make.py so that the functions in _make.py
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# don't have a direct reference to the thread-local in their globals dict.
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# If they have such a reference, it breaks cloudpickle.
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repr_context = threading.local()
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