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bpo-43977: Use tp_flags for collection matching (GH-25723)

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* Add Py_TPFLAGS_SEQUENCE and Py_TPFLAGS_MAPPING, add to all relevant standard builtin classes.

* Set relevant flags on collections.abc.Sequence and Mapping.

* Use flags in MATCH_SEQUENCE and MATCH_MAPPING opcodes.

* Inherit Py_TPFLAGS_SEQUENCE and Py_TPFLAGS_MAPPING.

* Add NEWS

* Remove interpreter-state map_abc and seq_abc fields.
This commit is contained in:
Mark Shannon 2021-04-30 09:50:28 +01:00 committed by GitHub
parent 2abbd8f2ad
commit 069e81ab3d
No known key found for this signature in database
GPG key ID: 4AEE18F83AFDEB23
16 changed files with 74 additions and 83 deletions
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4
Include/internal/pycore_interp.h
View file

@ -247,10 +247,6 @@ struct _is {
// importlib module
PyObject *importlib;
// Kept handy for pattern matching:
PyObject *map_abc; // _collections_abc.Mapping
PyObject *seq_abc; // _collections_abc.Sequence
/* Used in Modules/_threadmodule.c. */
long num_threads;
/* Support for runtime thread stack size tuning.

7
Include/object.h
View file

@ -320,6 +320,13 @@ Code can use PyType_HasFeature(type_ob, flag_value) to test whether the
given type object has a specified feature.
*/
#ifndef Py_LIMITED_API
/* Set if instances of the type object are treated as sequences for pattern matching */
#define Py_TPFLAGS_SEQUENCE (1 << 5)
/* Set if instances of the type object are treated as mappings for pattern matching */
#define Py_TPFLAGS_MAPPING (1 << 6)
#endif
/* Set if the type object is immutable: type attributes cannot be set nor deleted */
#define Py_TPFLAGS_IMMUTABLETYPE (1UL << 8)

10
Lib/_collections_abc.py
View file

@ -793,7 +793,6 @@ def __isub__(self, it):
### MAPPINGS ###
class Mapping(Collection):
"""A Mapping is a generic container for associating key/value
pairs.
@ -804,6 +803,9 @@ class Mapping(Collection):
__slots__ = ()
# Tell ABCMeta.__new__ that this class should have TPFLAGS_MAPPING set.
__abc_tpflags__ = 1 << 6 # Py_TPFLAGS_MAPPING
@abstractmethod
def __getitem__(self, key):
raise KeyError
@ -842,7 +844,6 @@ def __eq__(self, other):
__reversed__ = None
Mapping.register(mappingproxy)
@ -1011,7 +1012,6 @@ def setdefault(self, key, default=None):
### SEQUENCES ###
class Sequence(Reversible, Collection):
"""All the operations on a read-only sequence.
@ -1021,6 +1021,9 @@ class Sequence(Reversible, Collection):
__slots__ = ()
# Tell ABCMeta.__new__ that this class should have TPFLAGS_SEQUENCE set.
__abc_tpflags__ = 1 << 5 # Py_TPFLAGS_SEQUENCE
@abstractmethod
def __getitem__(self, index):
raise IndexError
@ -1072,7 +1075,6 @@ def count(self, value):
'S.count(value) -> integer -- return number of occurrences of value'
return sum(1 for v in self if v is value or v == value)
Sequence.register(tuple)
Sequence.register(str)
Sequence.register(range)

2
Misc/NEWS.d/next/Core and Builtins/2021-04-29-17-40-25.bpo-43977.FrQhge.rst Normal file
View file

@ -0,0 +1,2 @@
Use :c:member:`~PyTypeObject.tp_flags` on the class object to determine if the subject is a sequence
or mapping when pattern matching. Avoids the need to import :mod:`collections.abc` when pattern matching.

33
Modules/_abc.c
View file

@ -15,6 +15,7 @@ PyDoc_STRVAR(_abc__doc__,
_Py_IDENTIFIER(__abstractmethods__);
_Py_IDENTIFIER(__class__);
_Py_IDENTIFIER(__dict__);
_Py_IDENTIFIER(__abc_tpflags__);
_Py_IDENTIFIER(__bases__);
_Py_IDENTIFIER(_abc_impl);
_Py_IDENTIFIER(__subclasscheck__);
@ -417,6 +418,8 @@ compute_abstract_methods(PyObject *self)
return ret;
}
#define COLLECTION_FLAGS (Py_TPFLAGS_SEQUENCE | Py_TPFLAGS_MAPPING)
/*[clinic input]
_abc._abc_init
@ -446,6 +449,31 @@ _abc__abc_init(PyObject *module, PyObject *self)
return NULL;
}
Py_DECREF(data);
/* If __abc_tpflags__ & COLLECTION_FLAGS is set, then set the corresponding bit(s)
* in the new class.
* Used by collections.abc.Sequence and collections.abc.Mapping to indicate
* their special status w.r.t. pattern matching. */
if (PyType_Check(self)) {
PyTypeObject *cls = (PyTypeObject *)self;
PyObject *flags = _PyDict_GetItemIdWithError(cls->tp_dict, &PyId___abc_tpflags__);
if (flags == NULL) {
if (PyErr_Occurred()) {
return NULL;
}
}
else {
if (PyLong_CheckExact(flags)) {
long val = PyLong_AsLong(flags);
if (val == -1 && PyErr_Occurred()) {
return NULL;
}
((PyTypeObject *)self)->tp_flags |= (val & COLLECTION_FLAGS);
}
if (_PyDict_DelItemId(cls->tp_dict, &PyId___abc_tpflags__) < 0) {
return NULL;
}
}
}
Py_RETURN_NONE;
}
@ -499,6 +527,11 @@ _abc__abc_register_impl(PyObject *module, PyObject *self, PyObject *subclass)
/* Invalidate negative cache */
get_abc_state(module)->abc_invalidation_counter++;
if (PyType_Check(subclass) && PyType_Check(self) &&
!PyType_HasFeature((PyTypeObject *)subclass, Py_TPFLAGS_IMMUTABLETYPE))
{
((PyTypeObject *)subclass)->tp_flags |= (((PyTypeObject *)self)->tp_flags & COLLECTION_FLAGS);
}
Py_INCREF(subclass);
return subclass;
}

3
Modules/_collectionsmodule.c
View file

@ -1662,7 +1662,8 @@ static PyTypeObject deque_type = {
PyObject_GenericGetAttr, /* tp_getattro */
0, /* tp_setattro */
0, /* tp_as_buffer */
Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE | Py_TPFLAGS_HAVE_GC,
Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE |
Py_TPFLAGS_HAVE_GC | Py_TPFLAGS_SEQUENCE,
/* tp_flags */
deque_doc, /* tp_doc */
(traverseproc)deque_traverse, /* tp_traverse */

3
Modules/arraymodule.c
View file

@ -2848,7 +2848,8 @@ static PyType_Spec array_spec = {
.name = "array.array",
.basicsize = sizeof(arrayobject),
.flags = (Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE |
Py_TPFLAGS_IMMUTABLETYPE),
Py_TPFLAGS_IMMUTABLETYPE |
Py_TPFLAGS_SEQUENCE),
.slots = array_slots,
};

3
Objects/descrobject.c
View file

@ -1852,7 +1852,8 @@ PyTypeObject PyDictProxy_Type = {
PyObject_GenericGetAttr, /* tp_getattro */
0, /* tp_setattro */
0, /* tp_as_buffer */
Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC, /* tp_flags */
Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC |
Py_TPFLAGS_MAPPING, /* tp_flags */
0, /* tp_doc */
mappingproxy_traverse, /* tp_traverse */
0, /* tp_clear */

2
Objects/dictobject.c
View file

@ -3553,7 +3553,7 @@ PyTypeObject PyDict_Type = {
0, /* tp_as_buffer */
Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC |
Py_TPFLAGS_BASETYPE | Py_TPFLAGS_DICT_SUBCLASS |
_Py_TPFLAGS_MATCH_SELF, /* tp_flags */
_Py_TPFLAGS_MATCH_SELF | Py_TPFLAGS_MAPPING, /* tp_flags */
dictionary_doc, /* tp_doc */
dict_traverse, /* tp_traverse */
dict_tp_clear, /* tp_clear */

2
Objects/listobject.c
View file

@ -3053,7 +3053,7 @@ PyTypeObject PyList_Type = {
0, /* tp_as_buffer */
Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC |
Py_TPFLAGS_BASETYPE | Py_TPFLAGS_LIST_SUBCLASS |
_Py_TPFLAGS_MATCH_SELF, /* tp_flags */
_Py_TPFLAGS_MATCH_SELF | Py_TPFLAGS_SEQUENCE, /* tp_flags */
list___init____doc__, /* tp_doc */
(traverseproc)list_traverse, /* tp_traverse */
(inquiry)_list_clear, /* tp_clear */

3
Objects/memoryobject.c
View file

@ -3287,7 +3287,8 @@ PyTypeObject PyMemoryView_Type = {
PyObject_GenericGetAttr, /* tp_getattro */
0, /* tp_setattro */
&memory_as_buffer, /* tp_as_buffer */
Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC, /* tp_flags */
Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC |
Py_TPFLAGS_SEQUENCE, /* tp_flags */
memoryview__doc__, /* tp_doc */
(traverseproc)memory_traverse, /* tp_traverse */
(inquiry)memory_clear, /* tp_clear */

2
Objects/rangeobject.c
View file

@ -735,7 +735,7 @@ PyTypeObject PyRange_Type = {
PyObject_GenericGetAttr, /* tp_getattro */
0, /* tp_setattro */
0, /* tp_as_buffer */
Py_TPFLAGS_DEFAULT, /* tp_flags */
Py_TPFLAGS_DEFAULT | Py_TPFLAGS_SEQUENCE, /* tp_flags */
range_doc, /* tp_doc */
0, /* tp_traverse */
0, /* tp_clear */

2
Objects/tupleobject.c
View file

@ -918,7 +918,7 @@ PyTypeObject PyTuple_Type = {
0, /* tp_as_buffer */
Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC |
Py_TPFLAGS_BASETYPE | Py_TPFLAGS_TUPLE_SUBCLASS |
_Py_TPFLAGS_MATCH_SELF, /* tp_flags */
_Py_TPFLAGS_MATCH_SELF | Py_TPFLAGS_SEQUENCE, /* tp_flags */
tuple_new__doc__, /* tp_doc */
(traverseproc)tupletraverse, /* tp_traverse */
0, /* tp_clear */

7
Objects/typeobject.c
View file

@ -5717,10 +5717,15 @@ inherit_special(PyTypeObject *type, PyTypeObject *base)
else if (PyType_IsSubtype(base, &PyDict_Type)) {
type->tp_flags |= Py_TPFLAGS_DICT_SUBCLASS;
}
if (PyType_HasFeature(base, _Py_TPFLAGS_MATCH_SELF)) {
type->tp_flags |= _Py_TPFLAGS_MATCH_SELF;
}
if (PyType_HasFeature(base, Py_TPFLAGS_SEQUENCE)) {
type->tp_flags |= Py_TPFLAGS_SEQUENCE;
}
if (PyType_HasFeature(base, Py_TPFLAGS_MAPPING)) {
type->tp_flags |= Py_TPFLAGS_MAPPING;
}
}
static int

72
Python/ceval.c
View file

@ -3889,76 +3889,20 @@ _PyEval_EvalFrameDefault(PyThreadState *tstate, PyFrameObject *f, int throwflag)
}
case TARGET(MATCH_MAPPING): {
// PUSH(isinstance(TOS, _collections_abc.Mapping))
PyObject *subject = TOP();
// Fast path for dicts:
if (PyDict_Check(subject)) {
Py_INCREF(Py_True);
PUSH(Py_True);
DISPATCH();
}
// Lazily import _collections_abc.Mapping, and keep it handy on the
// PyInterpreterState struct (it gets cleaned up at exit):
PyInterpreterState *interp = PyInterpreterState_Get();
if (interp->map_abc == NULL) {
PyObject *abc = PyImport_ImportModule("_collections_abc");
if (abc == NULL) {
goto error;
}
interp->map_abc = PyObject_GetAttrString(abc, "Mapping");
if (interp->map_abc == NULL) {
goto error;
}
}
int match = PyObject_IsInstance(subject, interp->map_abc);
if (match < 0) {
goto error;
}
PUSH(PyBool_FromLong(match));
int match = Py_TYPE(subject)->tp_flags & Py_TPFLAGS_MAPPING;
PyObject *res = match ? Py_True : Py_False;
Py_INCREF(res);
PUSH(res);
DISPATCH();
}
case TARGET(MATCH_SEQUENCE): {
// PUSH(not isinstance(TOS, (bytearray, bytes, str))
// and isinstance(TOS, _collections_abc.Sequence))
PyObject *subject = TOP();
// Fast path for lists and tuples:
if (PyType_FastSubclass(Py_TYPE(subject),
Py_TPFLAGS_LIST_SUBCLASS |
Py_TPFLAGS_TUPLE_SUBCLASS))
{
Py_INCREF(Py_True);
PUSH(Py_True);
DISPATCH();
}
// Bail on some possible Sequences that we intentionally exclude:
if (PyType_FastSubclass(Py_TYPE(subject),
Py_TPFLAGS_BYTES_SUBCLASS |
Py_TPFLAGS_UNICODE_SUBCLASS) ||
PyByteArray_Check(subject))
{
Py_INCREF(Py_False);
PUSH(Py_False);
DISPATCH();
}
// Lazily import _collections_abc.Sequence, and keep it handy on the
// PyInterpreterState struct (it gets cleaned up at exit):
PyInterpreterState *interp = PyInterpreterState_Get();
if (interp->seq_abc == NULL) {
PyObject *abc = PyImport_ImportModule("_collections_abc");
if (abc == NULL) {
goto error;
}
interp->seq_abc = PyObject_GetAttrString(abc, "Sequence");
if (interp->seq_abc == NULL) {
goto error;
}
}
int match = PyObject_IsInstance(subject, interp->seq_abc);
if (match < 0) {
goto error;
}
PUSH(PyBool_FromLong(match));
int match = Py_TYPE(subject)->tp_flags & Py_TPFLAGS_SEQUENCE;
PyObject *res = match ? Py_True : Py_False;
Py_INCREF(res);
PUSH(res);
DISPATCH();
}

2
Python/pystate.c
View file

@ -308,8 +308,6 @@ interpreter_clear(PyInterpreterState *interp, PyThreadState *tstate)
Py_CLEAR(interp->importlib);
Py_CLEAR(interp->import_func);
Py_CLEAR(interp->dict);
Py_CLEAR(interp->map_abc);
Py_CLEAR(interp->seq_abc);
#ifdef HAVE_FORK
Py_CLEAR(interp->before_forkers);
Py_CLEAR(interp->after_forkers_parent);