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Diffstat (limited to 'lib/spack/external/attr/_compat.py')
| -rw-r--r-- | lib/spack/external/attr/_compat.py | 242 |
1 files changed, 242 insertions, 0 deletions
diff --git a/lib/spack/external/attr/_compat.py b/lib/spack/external/attr/_compat.py new file mode 100644 index 0000000000..6939f338da --- /dev/null +++ b/lib/spack/external/attr/_compat.py @@ -0,0 +1,242 @@ +from __future__ import absolute_import, division, print_function + +import platform +import sys +import types +import warnings + + +PY2 = sys.version_info[0] == 2 +PYPY = platform.python_implementation() == "PyPy" + + +if PYPY or sys.version_info[:2] >= (3, 6): + ordered_dict = dict +else: + from collections import OrderedDict + + ordered_dict = OrderedDict + + +if PY2: + from collections import Mapping, Sequence + + from UserDict import IterableUserDict + + # We 'bundle' isclass instead of using inspect as importing inspect is + # fairly expensive (order of 10-15 ms for a modern machine in 2016) + def isclass(klass): + return isinstance(klass, (type, types.ClassType)) + + def new_class(name, bases, kwds, exec_body): + """ + A minimal stub of types.new_class that we need for make_class. + """ + ns = {} + exec_body(ns) + + return type(name, bases, ns) + + # TYPE is used in exceptions, repr(int) is different on Python 2 and 3. + TYPE = "type" + + def iteritems(d): + return d.iteritems() + + # Python 2 is bereft of a read-only dict proxy, so we make one! + class ReadOnlyDict(IterableUserDict): + """ + Best-effort read-only dict wrapper. + """ + + def __setitem__(self, key, val): + # We gently pretend we're a Python 3 mappingproxy. + raise TypeError( + "'mappingproxy' object does not support item assignment" + ) + + def update(self, _): + # We gently pretend we're a Python 3 mappingproxy. + raise AttributeError( + "'mappingproxy' object has no attribute 'update'" + ) + + def __delitem__(self, _): + # We gently pretend we're a Python 3 mappingproxy. + raise TypeError( + "'mappingproxy' object does not support item deletion" + ) + + def clear(self): + # We gently pretend we're a Python 3 mappingproxy. + raise AttributeError( + "'mappingproxy' object has no attribute 'clear'" + ) + + def pop(self, key, default=None): + # We gently pretend we're a Python 3 mappingproxy. + raise AttributeError( + "'mappingproxy' object has no attribute 'pop'" + ) + + def popitem(self): + # We gently pretend we're a Python 3 mappingproxy. + raise AttributeError( + "'mappingproxy' object has no attribute 'popitem'" + ) + + def setdefault(self, key, default=None): + # We gently pretend we're a Python 3 mappingproxy. + raise AttributeError( + "'mappingproxy' object has no attribute 'setdefault'" + ) + + def __repr__(self): + # Override to be identical to the Python 3 version. + return "mappingproxy(" + repr(self.data) + ")" + + def metadata_proxy(d): + res = ReadOnlyDict() + res.data.update(d) # We blocked update, so we have to do it like this. + return res + + def just_warn(*args, **kw): # pragma: no cover + """ + We only warn on Python 3 because we are not aware of any concrete + consequences of not setting the cell on Python 2. + """ + + +else: # Python 3 and later. + from collections.abc import Mapping, Sequence # noqa + + def just_warn(*args, **kw): + """ + We only warn on Python 3 because we are not aware of any concrete + consequences of not setting the cell on Python 2. + """ + 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, + ) + + def isclass(klass): + return isinstance(klass, type) + + TYPE = "class" + + def iteritems(d): + return d.items() + + new_class = types.new_class + + def metadata_proxy(d): + return types.MappingProxyType(dict(d)) + + +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. + + # 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 + + try: + # Extract the code object and make sure our assumptions about + # the closure behavior are correct. + if PY2: + co = set_first_cellvar_to.func_code + else: + 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. + if sys.version_info >= (3, 8): + # CPython 3.8+ has an incompatible CodeType signature + # (added a posonlyargcount argument) but also added + # CodeType.replace() to do this without counting parameters. + set_first_freevar_code = co.replace( + co_cellvars=co.co_freevars, co_freevars=co.co_cellvars + ) + else: + args = [co.co_argcount] + if not PY2: + 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 + + if PY2: + cell = make_func_with_cell().func_closure[0] + else: + 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() |