262 lines
8.2 KiB
Python
262 lines
8.2 KiB
Python
# SPDX-License-Identifier: MIT
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from __future__ import absolute_import, division, print_function
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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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PY2 = sys.version_info[0] == 2
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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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if PY2:
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from collections import Mapping, Sequence
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from UserDict import IterableUserDict
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# We 'bundle' isclass instead of using inspect as importing inspect is
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# fairly expensive (order of 10-15 ms for a modern machine in 2016)
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def isclass(klass):
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return isinstance(klass, (type, types.ClassType))
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def new_class(name, bases, kwds, exec_body):
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"""
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A minimal stub of types.new_class that we need for make_class.
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"""
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ns = {}
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exec_body(ns)
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return type(name, bases, ns)
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# TYPE is used in exceptions, repr(int) is different on Python 2 and 3.
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TYPE = "type"
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def iteritems(d):
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return d.iteritems()
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# Python 2 is bereft of a read-only dict proxy, so we make one!
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class ReadOnlyDict(IterableUserDict):
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"""
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Best-effort read-only dict wrapper.
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"""
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def __setitem__(self, key, val):
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# We gently pretend we're a Python 3 mappingproxy.
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raise TypeError(
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"'mappingproxy' object does not support item assignment"
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)
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def update(self, _):
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# We gently pretend we're a Python 3 mappingproxy.
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raise AttributeError(
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"'mappingproxy' object has no attribute 'update'"
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)
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def __delitem__(self, _):
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# We gently pretend we're a Python 3 mappingproxy.
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raise TypeError(
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"'mappingproxy' object does not support item deletion"
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)
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def clear(self):
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# We gently pretend we're a Python 3 mappingproxy.
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raise AttributeError(
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"'mappingproxy' object has no attribute 'clear'"
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)
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def pop(self, key, default=None):
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# We gently pretend we're a Python 3 mappingproxy.
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raise AttributeError(
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"'mappingproxy' object has no attribute 'pop'"
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)
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def popitem(self):
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# We gently pretend we're a Python 3 mappingproxy.
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raise AttributeError(
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"'mappingproxy' object has no attribute 'popitem'"
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)
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def setdefault(self, key, default=None):
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# We gently pretend we're a Python 3 mappingproxy.
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raise AttributeError(
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"'mappingproxy' object has no attribute 'setdefault'"
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)
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def __repr__(self):
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# Override to be identical to the Python 3 version.
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return "mappingproxy(" + repr(self.data) + ")"
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def metadata_proxy(d):
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res = ReadOnlyDict()
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res.data.update(d) # We blocked update, so we have to do it like this.
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return res
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def just_warn(*args, **kw): # pragma: no cover
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"""
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We only warn on Python 3 because we are not aware of any concrete
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consequences of not setting the cell on Python 2.
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"""
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else: # Python 3 and later.
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from collections.abc import Mapping, Sequence # noqa
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def just_warn(*args, **kw):
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"""
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We only warn on Python 3 because we are not aware of any concrete
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consequences of not setting the cell on Python 2.
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"""
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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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def isclass(klass):
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return isinstance(klass, type)
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TYPE = "class"
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def iteritems(d):
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return d.items()
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new_class = types.new_class
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def metadata_proxy(d):
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return types.MappingProxyType(dict(d))
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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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if PY2:
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co = set_first_cellvar_to.func_code
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else:
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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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# CPython 3.8+ has an incompatible CodeType signature
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# (added a posonlyargcount argument) but also added
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# CodeType.replace() to do this without counting parameters.
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set_first_freevar_code = co.replace(
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co_cellvars=co.co_freevars, co_freevars=co.co_cellvars
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)
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else:
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args = [co.co_argcount]
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if not PY2:
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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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if PY2:
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cell = make_func_with_cell().func_closure[0]
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else:
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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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