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chromium / external / github.com / python / cpython / ca878b6e45f9c7934842f7bb94274e671b155e09 / . / Objects / typeobject.c
blob: 4af7f0273aae91a948483bfc03e59b8be6d6051d [file] [log] [blame]
/* Type object implementation */
#include "Python.h"
#include "pycore_abstract.h" // _PySequence_IterSearch()
#include "pycore_call.h" // _PyObject_VectorcallTstate()
#include "pycore_code.h" // CO_FAST_FREE
#include "pycore_dict.h" // _PyDict_KeysSize()
#include "pycore_frame.h" // _PyInterpreterFrame
#include "pycore_lock.h" // _PySeqLock_*
#include "pycore_long.h" // _PyLong_IsNegative(), _PyLong_GetOne()
#include "pycore_memoryobject.h" // _PyMemoryView_FromBufferProc()
#include "pycore_modsupport.h" // _PyArg_NoKwnames()
#include "pycore_moduleobject.h" // _PyModule_GetDef()
#include "pycore_object.h" // _PyType_HasFeature()
#include "pycore_object_alloc.h" // _PyObject_MallocWithType()
#include "pycore_pyerrors.h" // _PyErr_Occurred()
#include "pycore_pystate.h" // _PyThreadState_GET()
#include "pycore_symtable.h" // _Py_Mangle()
#include "pycore_typeobject.h" // struct type_cache
#include "pycore_unionobject.h" // _Py_union_type_or
#include "pycore_weakref.h" // _PyWeakref_GET_REF()
#include "opcode.h" // MAKE_CELL
#include <stddef.h> // ptrdiff_t
/*[clinic input]
class type "PyTypeObject *" "&PyType_Type"
class object "PyObject *" "&PyBaseObject_Type"
[clinic start generated code]*/
/*[clinic end generated code: output=da39a3ee5e6b4b0d input=4b94608d231c434b]*/
#include "clinic/typeobject.c.h"
/* Support type attribute lookup cache */
/* The cache can keep references to the names alive for longer than
they normally would. This is why the maximum size is limited to
MCACHE_MAX_ATTR_SIZE, since it might be a problem if very large
strings are used as attribute names. */
#define MCACHE_MAX_ATTR_SIZE 100
#define MCACHE_HASH(version, name_hash) \
(((unsigned int)(version) ^ (unsigned int)(name_hash)) \
& ((1 << MCACHE_SIZE_EXP) - 1))
#define MCACHE_HASH_METHOD(type, name) \
MCACHE_HASH(FT_ATOMIC_LOAD_UINT32_RELAXED((type)->tp_version_tag), \
((Py_ssize_t)(name)) >> 3)
#define MCACHE_CACHEABLE_NAME(name) \
PyUnicode_CheckExact(name) && \
PyUnicode_IS_READY(name) && \
(PyUnicode_GET_LENGTH(name) <= MCACHE_MAX_ATTR_SIZE)
#define NEXT_GLOBAL_VERSION_TAG _PyRuntime.types.next_version_tag
#define NEXT_VERSION_TAG(interp) \
(interp)->types.next_version_tag
#ifdef Py_GIL_DISABLED
// There's a global lock for mutation of types. This avoids having to take
// additional locks while doing various subclass processing which may result
// in odd behaviors w.r.t. running with the GIL as the outer type lock could
// be released and reacquired during a subclass update if there's contention
// on the subclass lock.
#define TYPE_LOCK &PyInterpreterState_Get()->types.mutex
#define BEGIN_TYPE_LOCK() Py_BEGIN_CRITICAL_SECTION_MUT(TYPE_LOCK)
#define END_TYPE_LOCK() Py_END_CRITICAL_SECTION()
#define BEGIN_TYPE_DICT_LOCK(d) \
Py_BEGIN_CRITICAL_SECTION2_MUT(TYPE_LOCK, &_PyObject_CAST(d)->ob_mutex)
#define END_TYPE_DICT_LOCK() Py_END_CRITICAL_SECTION2()
#define ASSERT_TYPE_LOCK_HELD() \
_Py_CRITICAL_SECTION_ASSERT_MUTEX_LOCKED(TYPE_LOCK)
#else
#define BEGIN_TYPE_LOCK()
#define END_TYPE_LOCK()
#define BEGIN_TYPE_DICT_LOCK(d)
#define END_TYPE_DICT_LOCK()
#define ASSERT_TYPE_LOCK_HELD()
#endif
typedef struct PySlot_Offset {
short subslot_offset;
short slot_offset;
} PySlot_Offset;
static void
slot_bf_releasebuffer(PyObject *self, Py_buffer *buffer);
static void
releasebuffer_call_python(PyObject *self, Py_buffer *buffer);
static PyObject *
slot_tp_new(PyTypeObject *type, PyObject *args, PyObject *kwds);
static PyObject *
lookup_maybe_method(PyObject *self, PyObject *attr, int *unbound);
static int
slot_tp_setattro(PyObject *self, PyObject *name, PyObject *value);
static inline PyTypeObject *
type_from_ref(PyObject *ref)
{
PyObject *obj = _PyWeakref_GET_REF(ref);
if (obj == NULL) {
return NULL;
}
return _PyType_CAST(obj);
}
/* helpers for for static builtin types */
#ifndef NDEBUG
static inline int
managed_static_type_index_is_set(PyTypeObject *self)
{
return self->tp_subclasses != NULL;
}
#endif
static inline size_t
managed_static_type_index_get(PyTypeObject *self)
{
assert(managed_static_type_index_is_set(self));
/* We store a 1-based index so 0 can mean "not initialized". */
return (size_t)self->tp_subclasses - 1;
}
static inline void
managed_static_type_index_set(PyTypeObject *self, size_t index)
{
assert(index < _Py_MAX_MANAGED_STATIC_BUILTIN_TYPES);
/* We store a 1-based index so 0 can mean "not initialized". */
self->tp_subclasses = (PyObject *)(index + 1);
}
static inline void
managed_static_type_index_clear(PyTypeObject *self)
{
self->tp_subclasses = NULL;
}
static PyTypeObject *
static_ext_type_lookup(PyInterpreterState *interp, size_t index,
int64_t *p_interp_count)
{
assert(interp->runtime == &_PyRuntime);
assert(index < _Py_MAX_MANAGED_STATIC_EXT_TYPES);
size_t full_index = index + _Py_MAX_MANAGED_STATIC_BUILTIN_TYPES;
int64_t interp_count =
_PyRuntime.types.managed_static.types[full_index].interp_count;
assert((interp_count == 0) ==
(_PyRuntime.types.managed_static.types[full_index].type == NULL));
*p_interp_count = interp_count;
PyTypeObject *type = interp->types.for_extensions.initialized[index].type;
if (type == NULL) {
return NULL;
}
assert(!interp->types.for_extensions.initialized[index].isbuiltin);
assert(type == _PyRuntime.types.managed_static.types[full_index].type);
assert(managed_static_type_index_is_set(type));
return type;
}
static managed_static_type_state *
managed_static_type_state_get(PyInterpreterState *interp, PyTypeObject *self)
{
// It's probably a builtin type.
size_t index = managed_static_type_index_get(self);
managed_static_type_state *state =
&(interp->types.builtins.initialized[index]);
if (state->type == self) {
return state;
}
if (index > _Py_MAX_MANAGED_STATIC_EXT_TYPES) {
return state;
}
return &(interp->types.for_extensions.initialized[index]);
}
/* For static types we store some state in an array on each interpreter. */
managed_static_type_state *
_PyStaticType_GetState(PyInterpreterState *interp, PyTypeObject *self)
{
assert(self->tp_flags & _Py_TPFLAGS_STATIC_BUILTIN);
return managed_static_type_state_get(interp, self);
}
/* Set the type's per-interpreter state. */
static void
managed_static_type_state_init(PyInterpreterState *interp, PyTypeObject *self,
int isbuiltin, int initial)
{
assert(interp->runtime == &_PyRuntime);
size_t index;
if (initial) {
assert(!managed_static_type_index_is_set(self));
if (isbuiltin) {
index = interp->types.builtins.num_initialized;
assert(index < _Py_MAX_MANAGED_STATIC_BUILTIN_TYPES);
}
else {
PyMutex_Lock(&interp->types.mutex);
index = interp->types.for_extensions.next_index;
interp->types.for_extensions.next_index++;
PyMutex_Unlock(&interp->types.mutex);
assert(index < _Py_MAX_MANAGED_STATIC_EXT_TYPES);
}
managed_static_type_index_set(self, index);
}
else {
index = managed_static_type_index_get(self);
if (isbuiltin) {
assert(index == interp->types.builtins.num_initialized);
assert(index < _Py_MAX_MANAGED_STATIC_BUILTIN_TYPES);
}
else {
assert(index < _Py_MAX_MANAGED_STATIC_EXT_TYPES);
}
}
size_t full_index = isbuiltin
? index
: index + _Py_MAX_MANAGED_STATIC_BUILTIN_TYPES;
assert((initial == 1) ==
(_PyRuntime.types.managed_static.types[full_index].interp_count == 0));
(void)_Py_atomic_add_int64(
&_PyRuntime.types.managed_static.types[full_index].interp_count, 1);
if (initial) {
assert(_PyRuntime.types.managed_static.types[full_index].type == NULL);
_PyRuntime.types.managed_static.types[full_index].type = self;
}
else {
assert(_PyRuntime.types.managed_static.types[full_index].type == self);
}
managed_static_type_state *state = isbuiltin
? &(interp->types.builtins.initialized[index])
: &(interp->types.for_extensions.initialized[index]);
/* It should only be called once for each builtin type per interpreter. */
assert(state->type == NULL);
state->type = self;
state->isbuiltin = isbuiltin;
/* state->tp_subclasses is left NULL until init_subclasses() sets it. */
/* state->tp_weaklist is left NULL until insert_head() or insert_after()
(in weakrefobject.c) sets it. */
if (isbuiltin) {
interp->types.builtins.num_initialized++;
}
else {
interp->types.for_extensions.num_initialized++;
}
}
/* Reset the type's per-interpreter state.
This basically undoes what managed_static_type_state_init() did. */
static void
managed_static_type_state_clear(PyInterpreterState *interp, PyTypeObject *self,
int isbuiltin, int final)
{
size_t index = managed_static_type_index_get(self);
size_t full_index = isbuiltin
? index
: index + _Py_MAX_MANAGED_STATIC_BUILTIN_TYPES;
managed_static_type_state *state = isbuiltin
? &(interp->types.builtins.initialized[index])
: &(interp->types.for_extensions.initialized[index]);
assert(state != NULL);
assert(_PyRuntime.types.managed_static.types[full_index].interp_count > 0);
assert(_PyRuntime.types.managed_static.types[full_index].type == state->type);
assert(state->type != NULL);
state->type = NULL;
assert(state->tp_weaklist == NULL); // It was already cleared out.
(void)_Py_atomic_add_int64(
&_PyRuntime.types.managed_static.types[full_index].interp_count, -1);
if (final) {
assert(!_PyRuntime.types.managed_static.types[full_index].interp_count);
_PyRuntime.types.managed_static.types[full_index].type = NULL;
managed_static_type_index_clear(self);
}
if (isbuiltin) {
assert(interp->types.builtins.num_initialized > 0);
interp->types.builtins.num_initialized--;
}
else {
PyMutex_Lock(&interp->types.mutex);
assert(interp->types.for_extensions.num_initialized > 0);
interp->types.for_extensions.num_initialized--;
if (interp->types.for_extensions.num_initialized == 0) {
interp->types.for_extensions.next_index = 0;
}
PyMutex_Unlock(&interp->types.mutex);
}
}
PyObject *
_PyStaticType_GetBuiltins(void)
{
PyInterpreterState *interp = _PyInterpreterState_GET();
Py_ssize_t count = (Py_ssize_t)interp->types.builtins.num_initialized;
assert(count <= _Py_MAX_MANAGED_STATIC_BUILTIN_TYPES);
PyObject *results = PyList_New(count);
if (results == NULL) {
return NULL;
}
for (Py_ssize_t i = 0; i < count; i++) {
PyTypeObject *cls = interp->types.builtins.initialized[i].type;
assert(cls != NULL);
assert(interp->types.builtins.initialized[i].isbuiltin);
PyList_SET_ITEM(results, i, Py_NewRef((PyObject *)cls));
}
return results;
}
// Also see _PyStaticType_InitBuiltin() and _PyStaticType_FiniBuiltin().
/* end static builtin helpers */
static inline void
start_readying(PyTypeObject *type)
{
if (type->tp_flags & _Py_TPFLAGS_STATIC_BUILTIN) {
PyInterpreterState *interp = _PyInterpreterState_GET();
managed_static_type_state *state = managed_static_type_state_get(interp, type);
assert(state != NULL);
assert(!state->readying);
state->readying = 1;
return;
}
assert((type->tp_flags & Py_TPFLAGS_READYING) == 0);
type->tp_flags |= Py_TPFLAGS_READYING;
}
static inline void
stop_readying(PyTypeObject *type)
{
if (type->tp_flags & _Py_TPFLAGS_STATIC_BUILTIN) {
PyInterpreterState *interp = _PyInterpreterState_GET();
managed_static_type_state *state = managed_static_type_state_get(interp, type);
assert(state != NULL);
assert(state->readying);
state->readying = 0;
return;
}
assert(type->tp_flags & Py_TPFLAGS_READYING);
type->tp_flags &= ~Py_TPFLAGS_READYING;
}
static inline int
is_readying(PyTypeObject *type)
{
if (type->tp_flags & _Py_TPFLAGS_STATIC_BUILTIN) {
PyInterpreterState *interp = _PyInterpreterState_GET();
managed_static_type_state *state = managed_static_type_state_get(interp, type);
assert(state != NULL);
return state->readying;
}
return (type->tp_flags & Py_TPFLAGS_READYING) != 0;
}
/* accessors for objects stored on PyTypeObject */
static inline PyObject *
lookup_tp_dict(PyTypeObject *self)
{
if (self->tp_flags & _Py_TPFLAGS_STATIC_BUILTIN) {
PyInterpreterState *interp = _PyInterpreterState_GET();
managed_static_type_state *state = _PyStaticType_GetState(interp, self);
assert(state != NULL);
return state->tp_dict;
}
return self->tp_dict;
}
PyObject *
_PyType_GetDict(PyTypeObject *self)
{
/* It returns a borrowed reference. */
return lookup_tp_dict(self);
}
PyObject *
PyType_GetDict(PyTypeObject *self)
{
PyObject *dict = lookup_tp_dict(self);
return _Py_XNewRef(dict);
}
static inline void
set_tp_dict(PyTypeObject *self, PyObject *dict)
{
if (self->tp_flags & _Py_TPFLAGS_STATIC_BUILTIN) {
PyInterpreterState *interp = _PyInterpreterState_GET();
managed_static_type_state *state = _PyStaticType_GetState(interp, self);
assert(state != NULL);
state->tp_dict = dict;
return;
}
self->tp_dict = dict;
}
static inline void
clear_tp_dict(PyTypeObject *self)
{
if (self->tp_flags & _Py_TPFLAGS_STATIC_BUILTIN) {
PyInterpreterState *interp = _PyInterpreterState_GET();
managed_static_type_state *state = _PyStaticType_GetState(interp, self);
assert(state != NULL);
Py_CLEAR(state->tp_dict);
return;
}
Py_CLEAR(self->tp_dict);
}
static inline PyObject *
lookup_tp_bases(PyTypeObject *self)
{
return self->tp_bases;
}
PyObject *
_PyType_GetBases(PyTypeObject *self)
{
PyObject *res;
BEGIN_TYPE_LOCK();
res = lookup_tp_bases(self);
Py_INCREF(res);
END_TYPE_LOCK();
return res;
}
static inline void
set_tp_bases(PyTypeObject *self, PyObject *bases, int initial)
{
assert(PyTuple_CheckExact(bases));
if (self->tp_flags & _Py_TPFLAGS_STATIC_BUILTIN) {
// XXX tp_bases can probably be statically allocated for each
// static builtin type.
assert(initial);
assert(self->tp_bases == NULL);
if (PyTuple_GET_SIZE(bases) == 0) {
assert(self->tp_base == NULL);
}
else {
assert(PyTuple_GET_SIZE(bases) == 1);
assert(PyTuple_GET_ITEM(bases, 0) == (PyObject *)self->tp_base);
assert(self->tp_base->tp_flags & _Py_TPFLAGS_STATIC_BUILTIN);
assert(_Py_IsImmortal(self->tp_base));
}
_Py_SetImmortal(bases);
}
self->tp_bases = bases;
}
static inline void
clear_tp_bases(PyTypeObject *self, int final)
{
if (self->tp_flags & _Py_TPFLAGS_STATIC_BUILTIN) {
if (final) {
if (self->tp_bases != NULL) {
if (PyTuple_GET_SIZE(self->tp_bases) == 0) {
Py_CLEAR(self->tp_bases);
}
else {
assert(_Py_IsImmortal(self->tp_bases));
_Py_ClearImmortal(self->tp_bases);
}
}
}
return;
}
Py_CLEAR(self->tp_bases);
}
static inline PyObject *
lookup_tp_mro(PyTypeObject *self)
{
ASSERT_TYPE_LOCK_HELD();
return self->tp_mro;
}
PyObject *
_PyType_GetMRO(PyTypeObject *self)
{
#ifdef Py_GIL_DISABLED
PyObject *mro = _Py_atomic_load_ptr_relaxed(&self->tp_mro);
if (mro == NULL) {
return NULL;
}
if (_Py_TryIncrefCompare(&self->tp_mro, mro)) {
return mro;
}
BEGIN_TYPE_LOCK();
mro = lookup_tp_mro(self);
Py_XINCREF(mro);
END_TYPE_LOCK();
return mro;
#else
return Py_XNewRef(lookup_tp_mro(self));
#endif
}
static inline void
set_tp_mro(PyTypeObject *self, PyObject *mro, int initial)
{
assert(PyTuple_CheckExact(mro));
if (self->tp_flags & _Py_TPFLAGS_STATIC_BUILTIN) {
// XXX tp_mro can probably be statically allocated for each
// static builtin type.
assert(initial);
assert(self->tp_mro == NULL);
/* Other checks are done via set_tp_bases. */
_Py_SetImmortal(mro);
}
self->tp_mro = mro;
}
static inline void
clear_tp_mro(PyTypeObject *self, int final)
{
if (self->tp_flags & _Py_TPFLAGS_STATIC_BUILTIN) {
if (final) {
if (self->tp_mro != NULL) {
if (PyTuple_GET_SIZE(self->tp_mro) == 0) {
Py_CLEAR(self->tp_mro);
}
else {
assert(_Py_IsImmortal(self->tp_mro));
_Py_ClearImmortal(self->tp_mro);
}
}
}
return;
}
Py_CLEAR(self->tp_mro);
}
static PyObject *
init_tp_subclasses(PyTypeObject *self)
{
PyObject *subclasses = PyDict_New();
if (subclasses == NULL) {
return NULL;
}
if (self->tp_flags & _Py_TPFLAGS_STATIC_BUILTIN) {
PyInterpreterState *interp = _PyInterpreterState_GET();
managed_static_type_state *state = _PyStaticType_GetState(interp, self);
state->tp_subclasses = subclasses;
return subclasses;
}
self->tp_subclasses = (void *)subclasses;
return subclasses;
}
static void
clear_tp_subclasses(PyTypeObject *self)
{
/* Delete the dictionary to save memory. _PyStaticType_Dealloc()
callers also test if tp_subclasses is NULL to check if a static type
has no subclass. */
if (self->tp_flags & _Py_TPFLAGS_STATIC_BUILTIN) {
PyInterpreterState *interp = _PyInterpreterState_GET();
managed_static_type_state *state = _PyStaticType_GetState(interp, self);
Py_CLEAR(state->tp_subclasses);
return;
}
Py_CLEAR(self->tp_subclasses);
}
static inline PyObject *
lookup_tp_subclasses(PyTypeObject *self)
{
if (self->tp_flags & _Py_TPFLAGS_STATIC_BUILTIN) {
PyInterpreterState *interp = _PyInterpreterState_GET();
managed_static_type_state *state = _PyStaticType_GetState(interp, self);
assert(state != NULL);
return state->tp_subclasses;
}
return (PyObject *)self->tp_subclasses;
}
int
_PyType_HasSubclasses(PyTypeObject *self)
{
PyInterpreterState *interp = _PyInterpreterState_GET();
if (self->tp_flags & _Py_TPFLAGS_STATIC_BUILTIN
// XXX _PyStaticType_GetState() should never return NULL.
&& _PyStaticType_GetState(interp, self) == NULL)
{
return 0;
}
if (lookup_tp_subclasses(self) == NULL) {
return 0;
}
return 1;
}
PyObject*
_PyType_GetSubclasses(PyTypeObject *self)
{
PyObject *list = PyList_New(0);
if (list == NULL) {
return NULL;
}
PyObject *subclasses = lookup_tp_subclasses(self); // borrowed ref
if (subclasses == NULL) {
return list;
}
assert(PyDict_CheckExact(subclasses));
// The loop cannot modify tp_subclasses, there is no need
// to hold a strong reference (use a borrowed reference).
Py_ssize_t i = 0;
PyObject *ref; // borrowed ref
while (PyDict_Next(subclasses, &i, NULL, &ref)) {
PyTypeObject *subclass = type_from_ref(ref);
if (subclass == NULL) {
continue;
}
if (PyList_Append(list, _PyObject_CAST(subclass)) < 0) {
Py_DECREF(list);
Py_DECREF(subclass);
return NULL;
}
Py_DECREF(subclass);
}
return list;
}
/* end accessors for objects stored on PyTypeObject */
/*
* finds the beginning of the docstring's introspection signature.
* if present, returns a pointer pointing to the first '('.
* otherwise returns NULL.
*
* doesn't guarantee that the signature is valid, only that it
* has a valid prefix. (the signature must also pass skip_signature.)
*/
static const char *
find_signature(const char *name, const char *doc)
{
const char *dot;
size_t length;
if (!doc)
return NULL;
assert(name != NULL);
/* for dotted names like classes, only use the last component */
dot = strrchr(name, '.');
if (dot)
name = dot + 1;
length = strlen(name);
if (strncmp(doc, name, length))
return NULL;
doc += length;
if (*doc != '(')
return NULL;
return doc;
}
#define SIGNATURE_END_MARKER ")\n--\n\n"
#define SIGNATURE_END_MARKER_LENGTH 6
/*
* skips past the end of the docstring's introspection signature.
* (assumes doc starts with a valid signature prefix.)
*/
static const char *
skip_signature(const char *doc)
{
while (*doc) {
if ((*doc == *SIGNATURE_END_MARKER) &&
!strncmp(doc, SIGNATURE_END_MARKER, SIGNATURE_END_MARKER_LENGTH))
return doc + SIGNATURE_END_MARKER_LENGTH;
if ((*doc == '\n') && (doc[1] == '\n'))
return NULL;
doc++;
}
return NULL;
}
int
_PyType_CheckConsistency(PyTypeObject *type)
{
#define CHECK(expr) \
do { if (!(expr)) { _PyObject_ASSERT_FAILED_MSG((PyObject *)type, Py_STRINGIFY(expr)); } } while (0)
CHECK(!_PyObject_IsFreed((PyObject *)type));
if (!(type->tp_flags & Py_TPFLAGS_READY)) {
/* don't check static types before PyType_Ready() */
return 1;
}
CHECK(Py_REFCNT(type) >= 1);
CHECK(PyType_Check(type));
CHECK(!is_readying(type));
CHECK(lookup_tp_dict(type) != NULL);
if (type->tp_flags & Py_TPFLAGS_HAVE_GC) {
// bpo-44263: tp_traverse is required if Py_TPFLAGS_HAVE_GC is set.
// Note: tp_clear is optional.
CHECK(type->tp_traverse != NULL);
}
if (type->tp_flags & Py_TPFLAGS_DISALLOW_INSTANTIATION) {
CHECK(type->tp_new == NULL);
CHECK(PyDict_Contains(lookup_tp_dict(type), &_Py_ID(__new__)) == 0);
}
return 1;
#undef CHECK
}
static const char *
_PyType_DocWithoutSignature(const char *name, const char *internal_doc)
{
const char *doc = find_signature(name, internal_doc);
if (doc) {
doc = skip_signature(doc);
if (doc)
return doc;
}
return internal_doc;
}
PyObject *
_PyType_GetDocFromInternalDoc(const char *name, const char *internal_doc)
{
const char *doc = _PyType_DocWithoutSignature(name, internal_doc);
if (!doc || *doc == '\0') {
Py_RETURN_NONE;
}
return PyUnicode_FromString(doc);
}
static const char *
signature_from_flags(int flags)
{
switch (flags & ~METH_COEXIST) {
case METH_NOARGS:
return "($self, /)";
case METH_NOARGS|METH_CLASS:
return "($type, /)";
case METH_NOARGS|METH_STATIC:
return "()";
case METH_O:
return "($self, object, /)";
case METH_O|METH_CLASS:
return "($type, object, /)";
case METH_O|METH_STATIC:
return "(object, /)";
default:
return NULL;
}
}
PyObject *
_PyType_GetTextSignatureFromInternalDoc(const char *name, const char *internal_doc, int flags)
{
const char *start = find_signature(name, internal_doc);
const char *end;
if (start)
end = skip_signature(start);
else
end = NULL;
if (!end) {
start = signature_from_flags(flags);
if (start) {
return PyUnicode_FromString(start);
}
Py_RETURN_NONE;
}
/* back "end" up until it points just past the final ')' */
end -= SIGNATURE_END_MARKER_LENGTH - 1;
assert((end - start) >= 2); /* should be "()" at least */
assert(end[-1] == ')');
assert(end[0] == '\n');
return PyUnicode_FromStringAndSize(start, end - start);
}
static struct type_cache*
get_type_cache(void)
{
PyInterpreterState *interp = _PyInterpreterState_GET();
return &interp->types.type_cache;
}
static void
type_cache_clear(struct type_cache *cache, PyObject *value)
{
for (Py_ssize_t i = 0; i < (1 << MCACHE_SIZE_EXP); i++) {
struct type_cache_entry *entry = &cache->hashtable[i];
#ifdef Py_GIL_DISABLED
_PySeqLock_LockWrite(&entry->sequence);
#endif
entry->version = 0;
Py_XSETREF(entry->name, _Py_XNewRef(value));
entry->value = NULL;
#ifdef Py_GIL_DISABLED
_PySeqLock_UnlockWrite(&entry->sequence);
#endif
}
}
void
_PyType_InitCache(PyInterpreterState *interp)
{
struct type_cache *cache = &interp->types.type_cache;
for (Py_ssize_t i = 0; i < (1 << MCACHE_SIZE_EXP); i++) {
struct type_cache_entry *entry = &cache->hashtable[i];
assert(entry->name == NULL);
entry->version = 0;
// Set to None so _PyType_LookupRef() can use Py_SETREF(),
// rather than using slower Py_XSETREF().
entry->name = Py_None;
entry->value = NULL;
}
}
static unsigned int
_PyType_ClearCache(PyInterpreterState *interp)
{
struct type_cache *cache = &interp->types.type_cache;
// Set to None, rather than NULL, so _PyType_LookupRef() can
// use Py_SETREF() rather than using slower Py_XSETREF().
type_cache_clear(cache, Py_None);
return NEXT_VERSION_TAG(interp) - 1;
}
unsigned int
PyType_ClearCache(void)
{
PyInterpreterState *interp = _PyInterpreterState_GET();
return _PyType_ClearCache(interp);
}
void
_PyTypes_Fini(PyInterpreterState *interp)
{
struct type_cache *cache = &interp->types.type_cache;
type_cache_clear(cache, NULL);
// All the managed static types should have been finalized already.
assert(interp->types.for_extensions.num_initialized == 0);
for (size_t i = 0; i < _Py_MAX_MANAGED_STATIC_EXT_TYPES; i++) {
assert(interp->types.for_extensions.initialized[i].type == NULL);
}
assert(interp->types.builtins.num_initialized == 0);
for (size_t i = 0; i < _Py_MAX_MANAGED_STATIC_BUILTIN_TYPES; i++) {
assert(interp->types.builtins.initialized[i].type == NULL);
}
}
int
PyType_AddWatcher(PyType_WatchCallback callback)
{
PyInterpreterState *interp = _PyInterpreterState_GET();
// start at 1, 0 is reserved for cpython optimizer
for (int i = 1; i < TYPE_MAX_WATCHERS; i++) {
if (!interp->type_watchers[i]) {
interp->type_watchers[i] = callback;
return i;
}
}
PyErr_SetString(PyExc_RuntimeError, "no more type watcher IDs available");
return -1;
}
static inline int
validate_watcher_id(PyInterpreterState *interp, int watcher_id)
{
if (watcher_id < 0 || watcher_id >= TYPE_MAX_WATCHERS) {
PyErr_Format(PyExc_ValueError, "Invalid type watcher ID %d", watcher_id);
return -1;
}
if (!interp->type_watchers[watcher_id]) {
PyErr_Format(PyExc_ValueError, "No type watcher set for ID %d", watcher_id);
return -1;
}
return 0;
}
int
PyType_ClearWatcher(int watcher_id)
{
PyInterpreterState *interp = _PyInterpreterState_GET();
if (validate_watcher_id(interp, watcher_id) < 0) {
return -1;
}
interp->type_watchers[watcher_id] = NULL;
return 0;
}
static int assign_version_tag(PyInterpreterState *interp, PyTypeObject *type);
int
PyType_Watch(int watcher_id, PyObject* obj)
{
if (!PyType_Check(obj)) {
PyErr_SetString(PyExc_ValueError, "Cannot watch non-type");
return -1;
}
PyTypeObject *type = (PyTypeObject *)obj;
PyInterpreterState *interp = _PyInterpreterState_GET();
if (validate_watcher_id(interp, watcher_id) < 0) {
return -1;
}
// ensure we will get a callback on the next modification
BEGIN_TYPE_LOCK();
assign_version_tag(interp, type);
type->tp_watched |= (1 << watcher_id);
END_TYPE_LOCK();
return 0;
}
int
PyType_Unwatch(int watcher_id, PyObject* obj)
{
if (!PyType_Check(obj)) {
PyErr_SetString(PyExc_ValueError, "Cannot watch non-type");
return -1;
}
PyTypeObject *type = (PyTypeObject *)obj;
PyInterpreterState *interp = _PyInterpreterState_GET();
if (validate_watcher_id(interp, watcher_id)) {
return -1;
}
type->tp_watched &= ~(1 << watcher_id);
return 0;
}
static void
set_version_unlocked(PyTypeObject *tp, unsigned int version)
{
ASSERT_TYPE_LOCK_HELD();
#ifndef Py_GIL_DISABLED
PyInterpreterState *interp = _PyInterpreterState_GET();
// lookup the old version and set to null
if (tp->tp_version_tag != 0) {
PyTypeObject **slot =
interp->types.type_version_cache
+ (tp->tp_version_tag % TYPE_VERSION_CACHE_SIZE);
*slot = NULL;
}
if (version) {
tp->tp_versions_used++;
}
#else
if (version) {
_Py_atomic_add_uint16(&tp->tp_versions_used, 1);
}
#endif
FT_ATOMIC_STORE_UINT32_RELAXED(tp->tp_version_tag, version);
#ifndef Py_GIL_DISABLED
if (version != 0) {
PyTypeObject **slot =
interp->types.type_version_cache
+ (version % TYPE_VERSION_CACHE_SIZE);
*slot = tp;
}
#endif
}
static void
type_modified_unlocked(PyTypeObject *type)
{
/* Invalidate any cached data for the specified type and all
subclasses. This function is called after the base
classes, mro, or attributes of the type are altered.
Invariants:
- before tp_version_tag can be set on a type,
it must first be set on all super types.
This function clears the tp_version_tag of a
type (so it must first clear it on all subclasses). The
tp_version_tag value is meaningless when equal to zero.
We don't assign new version tags eagerly, but only as
needed.
*/
if (type->tp_version_tag == 0) {
return;
}
// Cannot modify static builtin types.
assert((type->tp_flags & _Py_TPFLAGS_STATIC_BUILTIN) == 0);
PyObject *subclasses = lookup_tp_subclasses(type);
if (subclasses != NULL) {
assert(PyDict_CheckExact(subclasses));
Py_ssize_t i = 0;
PyObject *ref;
while (PyDict_Next(subclasses, &i, NULL, &ref)) {
PyTypeObject *subclass = type_from_ref(ref);
if (subclass == NULL) {
continue;
}
type_modified_unlocked(subclass);
Py_DECREF(subclass);
}
}
// Notify registered type watchers, if any
if (type->tp_watched) {
PyInterpreterState *interp = _PyInterpreterState_GET();
int bits = type->tp_watched;
int i = 0;
while (bits) {
assert(i < TYPE_MAX_WATCHERS);
if (bits & 1) {
PyType_WatchCallback cb = interp->type_watchers[i];
if (cb && (cb(type) < 0)) {
PyErr_FormatUnraisable(
"Exception ignored in type watcher callback #%d for %R",
i, type);
}
}
i++;
bits >>= 1;
}
}
set_version_unlocked(type, 0); /* 0 is not a valid version tag */
if (PyType_HasFeature(type, Py_TPFLAGS_HEAPTYPE)) {
// This field *must* be invalidated if the type is modified (see the
// comment on struct _specialization_cache):
((PyHeapTypeObject *)type)->_spec_cache.getitem = NULL;
}
}
void
PyType_Modified(PyTypeObject *type)
{
// Quick check without the lock held
if (type->tp_version_tag == 0) {
return;
}
BEGIN_TYPE_LOCK();
type_modified_unlocked(type);
END_TYPE_LOCK();
}
static int
is_subtype_with_mro(PyObject *a_mro, PyTypeObject *a, PyTypeObject *b);
static void
type_mro_modified(PyTypeObject *type, PyObject *bases) {
/*
Check that all base classes or elements of the MRO of type are
able to be cached. This function is called after the base
classes or mro of the type are altered.
Unset HAVE_VERSION_TAG and VALID_VERSION_TAG if the type
has a custom MRO that includes a type which is not officially
super type, or if the type implements its own mro() method.
Called from mro_internal, which will subsequently be called on
each subclass when their mro is recursively updated.
*/
Py_ssize_t i, n;
int custom = !Py_IS_TYPE(type, &PyType_Type);
int unbound;
ASSERT_TYPE_LOCK_HELD();
if (custom) {
PyObject *mro_meth, *type_mro_meth;
mro_meth = lookup_maybe_method(
(PyObject *)type, &_Py_ID(mro), &unbound);
if (mro_meth == NULL) {
goto clear;
}
type_mro_meth = lookup_maybe_method(
(PyObject *)&PyType_Type, &_Py_ID(mro), &unbound);
if (type_mro_meth == NULL) {
Py_DECREF(mro_meth);
goto clear;
}
int custom_mro = (mro_meth != type_mro_meth);
Py_DECREF(mro_meth);
Py_DECREF(type_mro_meth);
if (custom_mro) {
goto clear;
}
}
n = PyTuple_GET_SIZE(bases);
for (i = 0; i < n; i++) {
PyObject *b = PyTuple_GET_ITEM(bases, i);
PyTypeObject *cls = _PyType_CAST(b);
if (!is_subtype_with_mro(lookup_tp_mro(type), type, cls)) {
goto clear;
}
}
return;
clear:
assert(!(type->tp_flags & _Py_TPFLAGS_STATIC_BUILTIN));
set_version_unlocked(type, 0); /* 0 is not a valid version tag */
if (PyType_HasFeature(type, Py_TPFLAGS_HEAPTYPE)) {
// This field *must* be invalidated if the type is modified (see the
// comment on struct _specialization_cache):
((PyHeapTypeObject *)type)->_spec_cache.getitem = NULL;
}
}
/*
The Tier 2 interpreter requires looking up the type object by the type version, so it can install
watchers to understand when they change.
So we add a global cache from type version to borrowed references of type objects.
This is similar to func_version_cache.
*/
void
_PyType_SetVersion(PyTypeObject *tp, unsigned int version)
{
BEGIN_TYPE_LOCK();
set_version_unlocked(tp, version);
END_TYPE_LOCK();
}
PyTypeObject *
_PyType_LookupByVersion(unsigned int version)
{
#ifdef Py_GIL_DISABLED
return NULL;
#else
PyInterpreterState *interp = _PyInterpreterState_GET();
PyTypeObject **slot =
interp->types.type_version_cache
+ (version % TYPE_VERSION_CACHE_SIZE);
if (*slot && (*slot)->tp_version_tag == version) {
return *slot;
}
return NULL;
#endif
}
unsigned int
_PyType_GetVersionForCurrentState(PyTypeObject *tp)
{
return tp->tp_version_tag;
}
#define MAX_VERSIONS_PER_CLASS 1000
static int
assign_version_tag(PyInterpreterState *interp, PyTypeObject *type)
{
ASSERT_TYPE_LOCK_HELD();
/* Ensure that the tp_version_tag is valid.
* To respect the invariant, this must first be done on all super classes.
* Return 0 if this cannot be done, 1 if tp_version_tag is set.
*/
if (type->tp_version_tag != 0) {
return 1;
}
if (!_PyType_HasFeature(type, Py_TPFLAGS_READY)) {
return 0;
}
if (type->tp_versions_used >= MAX_VERSIONS_PER_CLASS) {
return 0;
}
PyObject *bases = lookup_tp_bases(type);
Py_ssize_t n = PyTuple_GET_SIZE(bases);
for (Py_ssize_t i = 0; i < n; i++) {
PyObject *b = PyTuple_GET_ITEM(bases, i);
if (!assign_version_tag(interp, _PyType_CAST(b))) {
return 0;
}
}
if (type->tp_flags & Py_TPFLAGS_IMMUTABLETYPE) {
/* static types */
if (NEXT_GLOBAL_VERSION_TAG > _Py_MAX_GLOBAL_TYPE_VERSION_TAG) {
/* We have run out of version numbers */
return 0;
}
set_version_unlocked(type, NEXT_GLOBAL_VERSION_TAG++);
assert (type->tp_version_tag <= _Py_MAX_GLOBAL_TYPE_VERSION_TAG);
}
else {
/* heap types */
if (NEXT_VERSION_TAG(interp) == 0) {
/* We have run out of version numbers */
return 0;
}
set_version_unlocked(type, NEXT_VERSION_TAG(interp)++);
assert (type->tp_version_tag != 0);
}
return 1;
}
int PyUnstable_Type_AssignVersionTag(PyTypeObject *type)
{
PyInterpreterState *interp = _PyInterpreterState_GET();
int assigned;
BEGIN_TYPE_LOCK();
assigned = assign_version_tag(interp, type);
END_TYPE_LOCK();
return assigned;
}
static PyMemberDef type_members[] = {
{"__basicsize__", Py_T_PYSSIZET, offsetof(PyTypeObject,tp_basicsize),Py_READONLY},
{"__itemsize__", Py_T_PYSSIZET, offsetof(PyTypeObject, tp_itemsize), Py_READONLY},
{"__flags__", Py_T_ULONG, offsetof(PyTypeObject, tp_flags), Py_READONLY},
/* Note that this value is misleading for static builtin types,
since the memory at this offset will always be NULL. */
{"__weakrefoffset__", Py_T_PYSSIZET,
offsetof(PyTypeObject, tp_weaklistoffset), Py_READONLY},
{"__base__", _Py_T_OBJECT, offsetof(PyTypeObject, tp_base), Py_READONLY},
{"__dictoffset__", Py_T_PYSSIZET,
offsetof(PyTypeObject, tp_dictoffset), Py_READONLY},
{0}
};
static int
check_set_special_type_attr(PyTypeObject *type, PyObject *value, const char *name)
{
if (_PyType_HasFeature(type, Py_TPFLAGS_IMMUTABLETYPE)) {
PyErr_Format(PyExc_TypeError,
"cannot set '%s' attribute of immutable type '%s'",
name, type->tp_name);
return 0;
}
if (!value) {
PyErr_Format(PyExc_TypeError,
"cannot delete '%s' attribute of immutable type '%s'",
name, type->tp_name);
return 0;
}
if (PySys_Audit("object.__setattr__", "OsO",
type, name, value) < 0) {
return 0;
}
return 1;
}
const char *
_PyType_Name(PyTypeObject *type)
{
assert(type->tp_name != NULL);
const char *s = strrchr(type->tp_name, '.');
if (s == NULL) {
s = type->tp_name;
}
else {
s++;
}
return s;
}
static PyObject *
type_name(PyTypeObject *type, void *context)
{
if (type->tp_flags & Py_TPFLAGS_HEAPTYPE) {
PyHeapTypeObject* et = (PyHeapTypeObject*)type;
return Py_NewRef(et->ht_name);
}
else {
return PyUnicode_FromString(_PyType_Name(type));
}
}
static PyObject *
type_qualname(PyTypeObject *type, void *context)
{
if (type->tp_flags & Py_TPFLAGS_HEAPTYPE) {
PyHeapTypeObject* et = (PyHeapTypeObject*)type;
return Py_NewRef(et->ht_qualname);
}
else {
return PyUnicode_FromString(_PyType_Name(type));
}
}
static int
type_set_name(PyTypeObject *type, PyObject *value, void *context)
{
const char *tp_name;
Py_ssize_t name_size;
if (!check_set_special_type_attr(type, value, "__name__"))
return -1;
if (!PyUnicode_Check(value)) {
PyErr_Format(PyExc_TypeError,
"can only assign string to %s.__name__, not '%s'",
type->tp_name, Py_TYPE(value)->tp_name);
return -1;
}
tp_name = PyUnicode_AsUTF8AndSize(value, &name_size);
if (tp_name == NULL)
return -1;
if (strlen(tp_name) != (size_t)name_size) {
PyErr_SetString(PyExc_ValueError,
"type name must not contain null characters");
return -1;
}
type->tp_name = tp_name;
Py_SETREF(((PyHeapTypeObject*)type)->ht_name, Py_NewRef(value));
return 0;
}
static int
type_set_qualname(PyTypeObject *type, PyObject *value, void *context)
{
PyHeapTypeObject* et;
if (!check_set_special_type_attr(type, value, "__qualname__"))
return -1;
if (!PyUnicode_Check(value)) {
PyErr_Format(PyExc_TypeError,
"can only assign string to %s.__qualname__, not '%s'",
type->tp_name, Py_TYPE(value)->tp_name);
return -1;
}
et = (PyHeapTypeObject*)type;
Py_SETREF(et->ht_qualname, Py_NewRef(value));
return 0;
}
static PyObject *
type_module(PyTypeObject *type)
{
PyObject *mod;
if (type->tp_flags & Py_TPFLAGS_HEAPTYPE) {
PyObject *dict = lookup_tp_dict(type);
if (PyDict_GetItemRef(dict, &_Py_ID(__module__), &mod) == 0) {
PyErr_Format(PyExc_AttributeError, "__module__");
}
}
else {
const char *s = strrchr(type->tp_name, '.');
if (s != NULL) {
mod = PyUnicode_FromStringAndSize(
type->tp_name, (Py_ssize_t)(s - type->tp_name));
if (mod != NULL) {
PyInterpreterState *interp = _PyInterpreterState_GET();
_PyUnicode_InternMortal(interp, &mod);
}
}
else {
mod = &_Py_ID(builtins);
}
}
return mod;
}
static PyObject *
type_get_module(PyTypeObject *type, void *context)
{
return type_module(type);
}
static int
type_set_module(PyTypeObject *type, PyObject *value, void *context)
{
if (!check_set_special_type_attr(type, value, "__module__"))
return -1;
PyType_Modified(type);
PyObject *dict = lookup_tp_dict(type);
if (PyDict_Pop(dict, &_Py_ID(__firstlineno__), NULL) < 0) {
return -1;
}
return PyDict_SetItem(dict, &_Py_ID(__module__), value);
}
PyObject *
_PyType_GetFullyQualifiedName(PyTypeObject *type, char sep)
{
if (!(type->tp_flags & Py_TPFLAGS_HEAPTYPE)) {
return PyUnicode_FromString(type->tp_name);
}
PyObject *qualname = type_qualname(type, NULL);
if (qualname == NULL) {
return NULL;
}
PyObject *module = type_module(type);
if (module == NULL) {
Py_DECREF(qualname);
return NULL;
}
PyObject *result;
if (PyUnicode_Check(module)
&& !_PyUnicode_Equal(module, &_Py_ID(builtins))
&& !_PyUnicode_Equal(module, &_Py_ID(__main__)))
{
result = PyUnicode_FromFormat("%U%c%U", module, sep, qualname);
}
else {
result = Py_NewRef(qualname);
}
Py_DECREF(module);
Py_DECREF(qualname);
return result;
}
PyObject *
PyType_GetFullyQualifiedName(PyTypeObject *type)
{
return _PyType_GetFullyQualifiedName(type, '.');
}
static PyObject *
type_abstractmethods(PyTypeObject *type, void *context)
{
PyObject *mod = NULL;
/* type itself has an __abstractmethods__ descriptor (this). Don't return
that. */
if (type == &PyType_Type) {
PyErr_SetObject(PyExc_AttributeError, &_Py_ID(__abstractmethods__));
}
else {
PyObject *dict = lookup_tp_dict(type);
if (PyDict_GetItemRef(dict, &_Py_ID(__abstractmethods__), &mod) == 0) {
PyErr_SetObject(PyExc_AttributeError, &_Py_ID(__abstractmethods__));
}
}
return mod;
}
static int
type_set_abstractmethods(PyTypeObject *type, PyObject *value, void *context)
{
/* __abstractmethods__ should only be set once on a type, in
abc.ABCMeta.__new__, so this function doesn't do anything
special to update subclasses.
*/
int abstract, res;
PyObject *dict = lookup_tp_dict(type);
if (value != NULL) {
abstract = PyObject_IsTrue(value);
if (abstract < 0)
return -1;
res = PyDict_SetItem(dict, &_Py_ID(__abstractmethods__), value);
}
else {
abstract = 0;
res = PyDict_Pop(dict, &_Py_ID(__abstractmethods__), NULL);
if (res == 0) {
PyErr_SetObject(PyExc_AttributeError, &_Py_ID(__abstractmethods__));
return -1;
}
}
if (res < 0) {
return -1;
}
PyType_Modified(type);
if (abstract)
type->tp_flags |= Py_TPFLAGS_IS_ABSTRACT;
else
type->tp_flags &= ~Py_TPFLAGS_IS_ABSTRACT;
return 0;
}
static PyObject *
type_get_bases(PyTypeObject *type, void *context)
{
PyObject *bases = _PyType_GetBases(type);
if (bases == NULL) {
Py_RETURN_NONE;
}
return bases;
}
static PyObject *
type_get_mro(PyTypeObject *type, void *context)
{
PyObject *mro;
BEGIN_TYPE_LOCK();
mro = lookup_tp_mro(type);
if (mro == NULL) {
mro = Py_None;
} else {
Py_INCREF(mro);
}
END_TYPE_LOCK();
return mro;
}
static PyTypeObject *best_base(PyObject *);
static int mro_internal(PyTypeObject *, PyObject **);
static int type_is_subtype_base_chain(PyTypeObject *, PyTypeObject *);
static int compatible_for_assignment(PyTypeObject *, PyTypeObject *, const char *);
static int add_subclass(PyTypeObject*, PyTypeObject*);
static int add_all_subclasses(PyTypeObject *type, PyObject *bases);
static void remove_subclass(PyTypeObject *, PyTypeObject *);
static void remove_all_subclasses(PyTypeObject *type, PyObject *bases);
static void update_all_slots(PyTypeObject *);
typedef int (*update_callback)(PyTypeObject *, void *);
static int update_subclasses(PyTypeObject *type, PyObject *attr_name,
update_callback callback, void *data);
static int recurse_down_subclasses(PyTypeObject *type, PyObject *name,
update_callback callback, void *data);
static int
mro_hierarchy(PyTypeObject *type, PyObject *temp)
{
ASSERT_TYPE_LOCK_HELD();
PyObject *old_mro;
int res = mro_internal(type, &old_mro);
if (res <= 0) {
/* error / reentrance */
return res;
}
PyObject *new_mro = lookup_tp_mro(type);
PyObject *tuple;
if (old_mro != NULL) {
tuple = PyTuple_Pack(3, type, new_mro, old_mro);
}
else {
tuple = PyTuple_Pack(2, type, new_mro);
}
if (tuple != NULL) {
res = PyList_Append(temp, tuple);
}
else {
res = -1;
}
Py_XDECREF(tuple);
if (res < 0) {
set_tp_mro(type, old_mro, 0);
Py_DECREF(new_mro);
return -1;
}
Py_XDECREF(old_mro);
// Avoid creating an empty list if there is no subclass
if (_PyType_HasSubclasses(type)) {
/* Obtain a copy of subclasses list to iterate over.
Otherwise type->tp_subclasses might be altered
in the middle of the loop, for example, through a custom mro(),
by invoking type_set_bases on some subclass of the type
which in turn calls remove_subclass/add_subclass on this type.
Finally, this makes things simple avoiding the need to deal
with dictionary iterators and weak references.
*/
PyObject *subclasses = _PyType_GetSubclasses(type);
if (subclasses == NULL) {
return -1;
}
Py_ssize_t n = PyList_GET_SIZE(subclasses);
for (Py_ssize_t i = 0; i < n; i++) {
PyTypeObject *subclass = _PyType_CAST(PyList_GET_ITEM(subclasses, i));
res = mro_hierarchy(subclass, temp);
if (res < 0) {
break;
}
}
Py_DECREF(subclasses);
}
return res;
}
static int
type_set_bases_unlocked(PyTypeObject *type, PyObject *new_bases, void *context)
{
// Check arguments
if (!check_set_special_type_attr(type, new_bases, "__bases__")) {
return -1;
}
assert(new_bases != NULL);
if (!PyTuple_Check(new_bases)) {
PyErr_Format(PyExc_TypeError,
"can only assign tuple to %s.__bases__, not %s",
type->tp_name, Py_TYPE(new_bases)->tp_name);
return -1;
}
if (PyTuple_GET_SIZE(new_bases) == 0) {
PyErr_Format(PyExc_TypeError,
"can only assign non-empty tuple to %s.__bases__, not ()",
type->tp_name);
return -1;
}
Py_ssize_t n = PyTuple_GET_SIZE(new_bases);
for (Py_ssize_t i = 0; i < n; i++) {
PyObject *ob = PyTuple_GET_ITEM(new_bases, i);
if (!PyType_Check(ob)) {
PyErr_Format(PyExc_TypeError,
"%s.__bases__ must be tuple of classes, not '%s'",
type->tp_name, Py_TYPE(ob)->tp_name);
return -1;
}
PyTypeObject *base = (PyTypeObject*)ob;
if (is_subtype_with_mro(lookup_tp_mro(base), base, type) ||
/* In case of reentering here again through a custom mro()
the above check is not enough since it relies on
base->tp_mro which would gonna be updated inside
mro_internal only upon returning from the mro().
However, base->tp_base has already been assigned (see
below), which in turn may cause an inheritance cycle
through tp_base chain. And this is definitely
not what you want to ever happen. */
(lookup_tp_mro(base) != NULL
&& type_is_subtype_base_chain(base, type)))
{
PyErr_SetString(PyExc_TypeError,
"a __bases__ item causes an inheritance cycle");
return -1;
}
}
// Compute the new MRO and the new base class
PyTypeObject *new_base = best_base(new_bases);
if (new_base == NULL)
return -1;
if (!compatible_for_assignment(type->tp_base, new_base, "__bases__")) {
return -1;
}
PyObject *old_bases = lookup_tp_bases(type);
assert(old_bases != NULL);
PyTypeObject *old_base = type->tp_base;
set_tp_bases(type, Py_NewRef(new_bases), 0);
type->tp_base = (PyTypeObject *)Py_NewRef(new_base);
PyObject *temp = PyList_New(0);
if (temp == NULL) {
goto bail;
}
if (mro_hierarchy(type, temp) < 0) {
goto undo;
}
Py_DECREF(temp);
/* Take no action in case if type->tp_bases has been replaced
through reentrance. */
int res;
if (lookup_tp_bases(type) == new_bases) {
/* any base that was in __bases__ but now isn't, we
need to remove |type| from its tp_subclasses.
conversely, any class now in __bases__ that wasn't
needs to have |type| added to its subclasses. */
/* for now, sod that: just remove from all old_bases,
add to all new_bases */
remove_all_subclasses(type, old_bases);
res = add_all_subclasses(type, new_bases);
update_all_slots(type);
}
else {
res = 0;
}
RARE_EVENT_INC(set_bases);
Py_DECREF(old_bases);
Py_DECREF(old_base);
assert(_PyType_CheckConsistency(type));
return res;
undo:
n = PyList_GET_SIZE(temp);
for (Py_ssize_t i = n - 1; i >= 0; i--) {
PyTypeObject *cls;
PyObject *new_mro, *old_mro = NULL;
PyArg_UnpackTuple(PyList_GET_ITEM(temp, i),
"", 2, 3, &cls, &new_mro, &old_mro);
/* Do not rollback if cls has a newer version of MRO. */
if (lookup_tp_mro(cls) == new_mro) {
set_tp_mro(cls, Py_XNewRef(old_mro), 0);
Py_DECREF(new_mro);
}
}
Py_DECREF(temp);
bail:
if (lookup_tp_bases(type) == new_bases) {
assert(type->tp_base == new_base);
set_tp_bases(type, old_bases, 0);
type->tp_base = old_base;
Py_DECREF(new_bases);
Py_DECREF(new_base);
}
else {
Py_DECREF(old_bases);
Py_DECREF(old_base);
}
assert(_PyType_CheckConsistency(type));
return -1;
}
static int
type_set_bases(PyTypeObject *type, PyObject *new_bases, void *context)
{
int res;
BEGIN_TYPE_LOCK();
res = type_set_bases_unlocked(type, new_bases, context);
END_TYPE_LOCK();
return res;
}
static PyObject *
type_dict(PyTypeObject *type, void *context)
{
PyObject *dict = lookup_tp_dict(type);
if (dict == NULL) {
Py_RETURN_NONE;
}
return PyDictProxy_New(dict);
}
static PyObject *
type_get_doc(PyTypeObject *type, void *context)
{
PyObject *result;
if (!(type->tp_flags & Py_TPFLAGS_HEAPTYPE) && type->tp_doc != NULL) {
return _PyType_GetDocFromInternalDoc(type->tp_name, type->tp_doc);
}
PyObject *dict = lookup_tp_dict(type);
if (PyDict_GetItemRef(dict, &_Py_ID(__doc__), &result) == 0) {
result = Py_NewRef(Py_None);
}
else if (result) {
descrgetfunc descr_get = Py_TYPE(result)->tp_descr_get;
if (descr_get) {
Py_SETREF(result, descr_get(result, NULL, (PyObject *)type));
}
}
return result;
}
static PyObject *
type_get_text_signature(PyTypeObject *type, void *context)
{
return _PyType_GetTextSignatureFromInternalDoc(type->tp_name, type->tp_doc, 0);
}
static int
type_set_doc(PyTypeObject *type, PyObject *value, void *context)
{
if (!check_set_special_type_attr(type, value, "__doc__"))
return -1;
PyType_Modified(type);
PyObject *dict = lookup_tp_dict(type);
return PyDict_SetItem(dict, &_Py_ID(__doc__), value);
}
static PyObject *
type_get_annotate(PyTypeObject *type, void *Py_UNUSED(ignored))
{
if (!(type->tp_flags & Py_TPFLAGS_HEAPTYPE)) {
PyErr_Format(PyExc_AttributeError, "type object '%s' has no attribute '__annotate__'", type->tp_name);
return NULL;
}
PyObject *annotate;
PyObject *dict = PyType_GetDict(type);
if (PyDict_GetItemRef(dict, &_Py_ID(__annotate__), &annotate) < 0) {
Py_DECREF(dict);
return NULL;
}
if (annotate) {
descrgetfunc get = Py_TYPE(annotate)->tp_descr_get;
if (get) {
Py_SETREF(annotate, get(annotate, NULL, (PyObject *)type));
}
}
else {
annotate = Py_None;
int result = PyDict_SetItem(dict, &_Py_ID(__annotate__), annotate);
if (result < 0) {
Py_DECREF(dict);
return NULL;
}
}
Py_DECREF(dict);
return annotate;
}
static int
type_set_annotate(PyTypeObject *type, PyObject *value, void *Py_UNUSED(ignored))
{
if (value == NULL) {
PyErr_SetString(PyExc_TypeError, "cannot delete __annotate__ attribute");
return -1;
}
if (_PyType_HasFeature(type, Py_TPFLAGS_IMMUTABLETYPE)) {
PyErr_Format(PyExc_TypeError,
"cannot set '__annotate__' attribute of immutable type '%s'",
type->tp_name);
return -1;
}
if (!Py_IsNone(value) && !PyCallable_Check(value)) {
PyErr_SetString(PyExc_TypeError, "__annotate__ must be callable or None");
return -1;
}
PyObject *dict = PyType_GetDict(type);
assert(PyDict_Check(dict));
int result = PyDict_SetItem(dict, &_Py_ID(__annotate__), value);
if (result < 0) {
Py_DECREF(dict);
return -1;
}
if (!Py_IsNone(value)) {
if (PyDict_Pop(dict, &_Py_ID(__annotations__), NULL) == -1) {
Py_DECREF(dict);
PyType_Modified(type);
return -1;
}
}
Py_DECREF(dict);
PyType_Modified(type);
return 0;
}
static PyObject *
type_get_annotations(PyTypeObject *type, void *context)
{
if (!(type->tp_flags & Py_TPFLAGS_HEAPTYPE)) {
PyErr_Format(PyExc_AttributeError, "type object '%s' has no attribute '__annotations__'", type->tp_name);
return NULL;
}
PyObject *annotations;
PyObject *dict = PyType_GetDict(type);
if (PyDict_GetItemRef(dict, &_Py_ID(__annotations__), &annotations) < 0) {
Py_DECREF(dict);
return NULL;
}
if (annotations) {
descrgetfunc get = Py_TYPE(annotations)->tp_descr_get;
if (get) {
Py_SETREF(annotations, get(annotations, NULL, (PyObject *)type));
}
}
else {
PyObject *annotate = type_get_annotate(type, NULL);
if (annotate == NULL) {
Py_DECREF(dict);
return NULL;
}
if (PyCallable_Check(annotate)) {
PyObject *one = _PyLong_GetOne();
annotations = _PyObject_CallOneArg(annotate, one);
if (annotations == NULL) {
Py_DECREF(dict);
Py_DECREF(annotate);
return NULL;
}
if (!PyDict_Check(annotations)) {
PyErr_Format(PyExc_TypeError, "__annotate__ returned non-dict of type '%.100s'",
Py_TYPE(annotations)->tp_name);
Py_DECREF(annotations);
Py_DECREF(annotate);
Py_DECREF(dict);
return NULL;
}
}
else {
annotations = PyDict_New();
}
Py_DECREF(annotate);
if (annotations) {
int result = PyDict_SetItem(
dict, &_Py_ID(__annotations__), annotations);
if (result) {
Py_CLEAR(annotations);
} else {
PyType_Modified(type);
}
}
}
Py_DECREF(dict);
return annotations;
}
static int
type_set_annotations(PyTypeObject *type, PyObject *value, void *context)
{
if (_PyType_HasFeature(type, Py_TPFLAGS_IMMUTABLETYPE)) {
PyErr_Format(PyExc_TypeError,
"cannot set '__annotations__' attribute of immutable type '%s'",
type->tp_name);
return -1;
}
int result;
PyObject *dict = PyType_GetDict(type);
if (value != NULL) {
/* set */
result = PyDict_SetItem(dict, &_Py_ID(__annotations__), value);
} else {
/* delete */
result = PyDict_Pop(dict, &_Py_ID(__annotations__), NULL);
if (result == 0) {
PyErr_SetString(PyExc_AttributeError, "__annotations__");
Py_DECREF(dict);
return -1;
}
}
if (result < 0) {
Py_DECREF(dict);
return -1;
}
else if (result == 0) {
if (PyDict_Pop(dict, &_Py_ID(__annotate__), NULL) < 0) {
PyType_Modified(type);
Py_DECREF(dict);
return -1;
}
}
PyType_Modified(type);
Py_DECREF(dict);
return 0;
}
static PyObject *
type_get_type_params(PyTypeObject *type, void *context)
{
if (type == &PyType_Type) {
return PyTuple_New(0);
}
PyObject *params;
if (PyDict_GetItemRef(lookup_tp_dict(type), &_Py_ID(__type_params__), &params) == 0) {
return PyTuple_New(0);
}
return params;
}
static int
type_set_type_params(PyTypeObject *type, PyObject *value, void *context)
{
if (!check_set_special_type_attr(type, value, "__type_params__")) {
return -1;
}
PyObject *dict = lookup_tp_dict(type);
int result = PyDict_SetItem(dict, &_Py_ID(__type_params__), value);
if (result == 0) {
PyType_Modified(type);
}
return result;
}
/*[clinic input]
type.__instancecheck__ -> bool
instance: object
/
Check if an object is an instance.
[clinic start generated code]*/
static int
type___instancecheck___impl(PyTypeObject *self, PyObject *instance)
/*[clinic end generated code: output=08b6bf5f591c3618 input=cdbfeaee82c01a0f]*/
{
return _PyObject_RealIsInstance(instance, (PyObject *)self);
}
/*[clinic input]
type.__subclasscheck__ -> bool
subclass: object
/
Check if a class is a subclass.
[clinic start generated code]*/
static int
type___subclasscheck___impl(PyTypeObject *self, PyObject *subclass)
/*[clinic end generated code: output=97a4e51694500941 input=071b2ca9e03355f4]*/
{
return _PyObject_RealIsSubclass(subclass, (PyObject *)self);
}
static PyGetSetDef type_getsets[] = {
{"__name__", (getter)type_name, (setter)type_set_name, NULL},
{"__qualname__", (getter)type_qualname, (setter)type_set_qualname, NULL},
{"__bases__", (getter)type_get_bases, (setter)type_set_bases, NULL},
{"__mro__", (getter)type_get_mro, NULL, NULL},
{"__module__", (getter)type_get_module, (setter)type_set_module, NULL},
{"__abstractmethods__", (getter)type_abstractmethods,
(setter)type_set_abstractmethods, NULL},
{"__dict__", (getter)type_dict, NULL, NULL},
{"__doc__", (getter)type_get_doc, (setter)type_set_doc, NULL},
{"__text_signature__", (getter)type_get_text_signature, NULL, NULL},
{"__annotations__", (getter)type_get_annotations, (setter)type_set_annotations, NULL},
{"__annotate__", (getter)type_get_annotate, (setter)type_set_annotate, NULL},
{"__type_params__", (getter)type_get_type_params, (setter)type_set_type_params, NULL},
{0}
};
static PyObject *
type_repr(PyObject *self)
{
PyTypeObject *type = (PyTypeObject *)self;
if (type->tp_name == NULL) {
// type_repr() called before the type is fully initialized
// by PyType_Ready().
return PyUnicode_FromFormat("<class at %p>", type);
}
PyObject *mod = type_module(type);
if (mod == NULL) {
PyErr_Clear();
}
else if (!PyUnicode_Check(mod)) {
Py_CLEAR(mod);
}
PyObject *name = type_qualname(type, NULL);
if (name == NULL) {
Py_XDECREF(mod);
return NULL;
}
PyObject *result;
if (mod != NULL && !_PyUnicode_Equal(mod, &_Py_ID(builtins))) {
result = PyUnicode_FromFormat("<class '%U.%U'>", mod, name);
}
else {
result = PyUnicode_FromFormat("<class '%s'>", type->tp_name);
}
Py_XDECREF(mod);
Py_DECREF(name);
return result;
}
static PyObject *
type_call(PyObject *self, PyObject *args, PyObject *kwds)
{
PyTypeObject *type = (PyTypeObject *)self;
PyObject *obj;
PyThreadState *tstate = _PyThreadState_GET();
#ifdef Py_DEBUG
/* type_call() must not be called with an exception set,
because it can clear it (directly or indirectly) and so the
caller loses its exception */
assert(!_PyErr_Occurred(tstate));
#endif
/* Special case: type(x) should return Py_TYPE(x) */
/* We only want type itself to accept the one-argument form (#27157) */
if (type == &PyType_Type) {
assert(args != NULL && PyTuple_Check(args));
assert(kwds == NULL || PyDict_Check(kwds));
Py_ssize_t nargs = PyTuple_GET_SIZE(args);
if (nargs == 1 && (kwds == NULL || !PyDict_GET_SIZE(kwds))) {
obj = (PyObject *) Py_TYPE(PyTuple_GET_ITEM(args, 0));
return Py_NewRef(obj);
}
/* SF bug 475327 -- if that didn't trigger, we need 3
arguments. But PyArg_ParseTuple in type_new may give
a msg saying type() needs exactly 3. */
if (nargs != 3) {
PyErr_SetString(PyExc_TypeError,
"type() takes 1 or 3 arguments");
return NULL;
}
}
if (type->tp_new == NULL) {
_PyErr_Format(tstate, PyExc_TypeError,
"cannot create '%s' instances", type->tp_name);
return NULL;
}
obj = type->tp_new(type, args, kwds);
obj = _Py_CheckFunctionResult(tstate, (PyObject*)type, obj, NULL);
if (obj == NULL)
return NULL;
/* If the returned object is not an instance of type,
it won't be initialized. */
if (!PyObject_TypeCheck(obj, type))
return obj;
type = Py_TYPE(obj);
if (type->tp_init != NULL) {
int res = type->tp_init(obj, args, kwds);
if (res < 0) {
assert(_PyErr_Occurred(tstate));
Py_SETREF(obj, NULL);
}
else {
assert(!_PyErr_Occurred(tstate));
}
}
return obj;
}
PyObject *
_PyType_NewManagedObject(PyTypeObject *type)
{
assert(type->tp_flags & Py_TPFLAGS_INLINE_VALUES);
assert(_PyType_IS_GC(type));
assert(type->tp_new == PyBaseObject_Type.tp_new);
assert(type->tp_alloc == PyType_GenericAlloc);
assert(type->tp_itemsize == 0);
PyObject *obj = PyType_GenericAlloc(type, 0);
if (obj == NULL) {
return PyErr_NoMemory();
}
return obj;
}
PyObject *
_PyType_AllocNoTrack(PyTypeObject *type, Py_ssize_t nitems)
{
PyObject *obj;
/* The +1 on nitems is needed for most types but not all. We could save a
* bit of space by allocating one less item in certain cases, depending on
* the type. However, given the extra complexity (e.g. an additional type
* flag to indicate when that is safe) it does not seem worth the memory
* savings. An example type that doesn't need the +1 is a subclass of
* tuple. See GH-100659 and GH-81381. */
size_t size = _PyObject_VAR_SIZE(type, nitems+1);
const size_t presize = _PyType_PreHeaderSize(type);
if (type->tp_flags & Py_TPFLAGS_INLINE_VALUES) {
assert(type->tp_itemsize == 0);
size += _PyInlineValuesSize(type);
}
char *alloc = _PyObject_MallocWithType(type, size + presize);
if (alloc == NULL) {
return PyErr_NoMemory();
}
obj = (PyObject *)(alloc + presize);
if (presize) {
((PyObject **)alloc)[0] = NULL;
((PyObject **)alloc)[1] = NULL;
}
if (PyType_IS_GC(type)) {
_PyObject_GC_Link(obj);
}
memset(obj, '\0', size);
if (type->tp_itemsize == 0) {
_PyObject_Init(obj, type);
}
else {
_PyObject_InitVar((PyVarObject *)obj, type, nitems);
}
if (type->tp_flags & Py_TPFLAGS_INLINE_VALUES) {
_PyObject_InitInlineValues(obj, type);
}
return obj;
}
PyObject *
PyType_GenericAlloc(PyTypeObject *type, Py_ssize_t nitems)
{
PyObject *obj = _PyType_AllocNoTrack(type, nitems);
if (obj == NULL) {
return NULL;
}
if (_PyType_IS_GC(type)) {
_PyObject_GC_TRACK(obj);
}
return obj;
}
PyObject *
PyType_GenericNew(PyTypeObject *type, PyObject *args, PyObject *kwds)
{
return type->tp_alloc(type, 0);
}
/* Helpers for subtyping */
static inline PyMemberDef *
_PyHeapType_GET_MEMBERS(PyHeapTypeObject* type)
{
return PyObject_GetItemData((PyObject *)type);
}
static int
traverse_slots(PyTypeObject *type, PyObject *self, visitproc visit, void *arg)
{
Py_ssize_t i, n;
PyMemberDef *mp;
n = Py_SIZE(type);
mp = _PyHeapType_GET_MEMBERS((PyHeapTypeObject *)type);
for (i = 0; i < n; i++, mp++) {
if (mp->type == Py_T_OBJECT_EX) {
char *addr = (char *)self + mp->offset;
PyObject *obj = *(PyObject **)addr;
if (obj != NULL) {
int err = visit(obj, arg);
if (err)
return err;
}
}
}
return 0;
}
static int
subtype_traverse(PyObject *self, visitproc visit, void *arg)
{
PyTypeObject *type, *base;
traverseproc basetraverse;
/* Find the nearest base with a different tp_traverse,
and traverse slots while we're at it */
type = Py_TYPE(self);
base = type;
while ((basetraverse = base->tp_traverse) == subtype_traverse) {
if (Py_SIZE(base)) {
int err = traverse_slots(base, self, visit, arg);
if (err)
return err;
}
base = base->tp_base;
assert(base);
}
if (type->tp_dictoffset != base->tp_dictoffset) {
assert(base->tp_dictoffset == 0);
if (type->tp_flags & Py_TPFLAGS_MANAGED_DICT) {
assert(type->tp_dictoffset == -1);
int err = PyObject_VisitManagedDict(self, visit, arg);
if (err) {
return err;
}
}
else {
PyObject **dictptr = _PyObject_ComputedDictPointer(self);
if (dictptr && *dictptr) {
Py_VISIT(*dictptr);
}
}
}
if (type->tp_flags & Py_TPFLAGS_HEAPTYPE
&& (!basetraverse || !(base->tp_flags & Py_TPFLAGS_HEAPTYPE))) {
/* For a heaptype, the instances count as references
to the type. Traverse the type so the collector
can find cycles involving this link.
Skip this visit if basetraverse belongs to a heap type: in that
case, basetraverse will visit the type when we call it later.
*/
Py_VISIT(type);
}
if (basetraverse)
return basetraverse(self, visit, arg);
return 0;
}
static void
clear_slots(PyTypeObject *type, PyObject *self)
{
Py_ssize_t i, n;
PyMemberDef *mp;
n = Py_SIZE(type);
mp = _PyHeapType_GET_MEMBERS((PyHeapTypeObject *)type);
for (i = 0; i < n; i++, mp++) {
if (mp->type == Py_T_OBJECT_EX && !(mp->flags & Py_READONLY)) {
char *addr = (char *)self + mp->offset;
PyObject *obj = *(PyObject **)addr;
if (obj != NULL) {
*(PyObject **)addr = NULL;
Py_DECREF(obj);
}
}
}
}
static int
subtype_clear(PyObject *self)
{
PyTypeObject *type, *base;
inquiry baseclear;
/* Find the nearest base with a different tp_clear
and clear slots while we're at it */
type = Py_TYPE(self);
base = type;
while ((baseclear = base->tp_clear) == subtype_clear) {
if (Py_SIZE(base))
clear_slots(base, self);
base = base->tp_base;
assert(base);
}
/* Clear the instance dict (if any), to break cycles involving only
__dict__ slots (as in the case 'self.__dict__ is self'). */
if (type->tp_flags & Py_TPFLAGS_MANAGED_DICT) {
if ((base->tp_flags & Py_TPFLAGS_MANAGED_DICT) == 0) {
PyObject_ClearManagedDict(self);
}
else {
assert((base->tp_flags & Py_TPFLAGS_INLINE_VALUES) ==
(type->tp_flags & Py_TPFLAGS_INLINE_VALUES));
}
}
else if (type->tp_dictoffset != base->tp_dictoffset) {
PyObject **dictptr = _PyObject_ComputedDictPointer(self);
if (dictptr && *dictptr)
Py_CLEAR(*dictptr);
}
if (baseclear)
return baseclear(self);
return 0;
}
static void
subtype_dealloc(PyObject *self)
{
PyTypeObject *type, *base;
destructor basedealloc;
int has_finalizer;
/* Extract the type; we expect it to be a heap type */
type = Py_TYPE(self);
_PyObject_ASSERT((PyObject *)type, type->tp_flags & Py_TPFLAGS_HEAPTYPE);
/* Test whether the type has GC exactly once */
if (!_PyType_IS_GC(type)) {
/* A non GC dynamic type allows certain simplifications:
there's no need to call clear_slots(), or DECREF the dict,
or clear weakrefs. */
/* Maybe call finalizer; exit early if resurrected */
if (type->tp_finalize) {
if (PyObject_CallFinalizerFromDealloc(self) < 0)
return;
}
if (type->tp_del) {
type->tp_del(self);
if (Py_REFCNT(self) > 0) {
return;
}
}
/* Find the nearest base with a different tp_dealloc */
base = type;
while ((basedealloc = base->tp_dealloc) == subtype_dealloc) {
base = base->tp_base;
assert(base);
}
/* Extract the type again; tp_del may have changed it */
type = Py_TYPE(self);
// Don't read type memory after calling basedealloc() since basedealloc()
// can deallocate the type and free its memory.
int type_needs_decref = (type->tp_flags & Py_TPFLAGS_HEAPTYPE
&& !(base->tp_flags & Py_TPFLAGS_HEAPTYPE));
assert((type->tp_flags & Py_TPFLAGS_MANAGED_DICT) == 0);
/* Call the base tp_dealloc() */
assert(basedealloc);
basedealloc(self);
/* Can't reference self beyond this point. It's possible tp_del switched
our type from a HEAPTYPE to a non-HEAPTYPE, so be careful about
reference counting. Only decref if the base type is not already a heap
allocated type. Otherwise, basedealloc should have decref'd it already */
if (type_needs_decref) {
_Py_DECREF_TYPE(type);
}
/* Done */
return;
}
/* We get here only if the type has GC */
/* UnTrack and re-Track around the trashcan macro, alas */
/* See explanation at end of function for full disclosure */
PyObject_GC_UnTrack(self);
Py_TRASHCAN_BEGIN(self, subtype_dealloc);
/* Find the nearest base with a different tp_dealloc */
base = type;
while ((/*basedealloc =*/ base->tp_dealloc) == subtype_dealloc) {
base = base->tp_base;
assert(base);
}
has_finalizer = type->tp_finalize || type->tp_del;
if (type->tp_finalize) {
_PyObject_GC_TRACK(self);
if (PyObject_CallFinalizerFromDealloc(self) < 0) {
/* Resurrected */
goto endlabel;
}
_PyObject_GC_UNTRACK(self);
}
/*
If we added a weaklist, we clear it. Do this *before* calling tp_del,
clearing slots, or clearing the instance dict.
GC tracking must be off at this point. weakref callbacks (if any, and
whether directly here or indirectly in something we call) may trigger GC,
and if self is tracked at that point, it will look like trash to GC and GC
will try to delete self again.
*/
if (type->tp_weaklistoffset && !base->tp_weaklistoffset) {
PyObject_ClearWeakRefs(self);
}
if (type->tp_del) {
_PyObject_GC_TRACK(self);
type->tp_del(self);
if (Py_REFCNT(self) > 0) {
/* Resurrected */
goto endlabel;
}
_PyObject_GC_UNTRACK(self);
}
if (has_finalizer) {
/* New weakrefs could be created during the finalizer call.
If this occurs, clear them out without calling their
finalizers since they might rely on part of the object
being finalized that has already been destroyed. */
if (type->tp_weaklistoffset && !base->tp_weaklistoffset) {
_PyWeakref_ClearWeakRefsNoCallbacks(self);
}
}
/* Clear slots up to the nearest base with a different tp_dealloc */
base = type;
while ((basedealloc = base->tp_dealloc) == subtype_dealloc) {
if (Py_SIZE(base))
clear_slots(base, self);
base = base->tp_base;
assert(base);
}
/* If we added a dict, DECREF it, or free inline values. */
if (type->tp_flags & Py_TPFLAGS_MANAGED_DICT) {
PyObject_ClearManagedDict(self);
}
else if (type->tp_dictoffset && !base->tp_dictoffset) {
PyObject **dictptr = _PyObject_ComputedDictPointer(self);
if (dictptr != NULL) {
PyObject *dict = *dictptr;
if (dict != NULL) {
Py_DECREF(dict);
*dictptr = NULL;
}
}
}
/* Extract the type again; tp_del may have changed it */
type = Py_TYPE(self);
/* Call the base tp_dealloc(); first retrack self if
* basedealloc knows about gc.
*/
if (_PyType_IS_GC(base)) {
_PyObject_GC_TRACK(self);
}
// Don't read type memory after calling basedealloc() since basedealloc()
// can deallocate the type and free its memory.
int type_needs_decref = (type->tp_flags & Py_TPFLAGS_HEAPTYPE
&& !(base->tp_flags & Py_TPFLAGS_HEAPTYPE));
assert(basedealloc);
basedealloc(self);
/* Can't reference self beyond this point. It's possible tp_del switched
our type from a HEAPTYPE to a non-HEAPTYPE, so be careful about
reference counting. Only decref if the base type is not already a heap
allocated type. Otherwise, basedealloc should have decref'd it already */
if (type_needs_decref) {
_Py_DECREF_TYPE(type);
}
endlabel:
Py_TRASHCAN_END
/* Explanation of the weirdness around the trashcan macros:
Q. What do the trashcan macros do?
A. Read the comment titled "Trashcan mechanism" in object.h.
For one, this explains why there must be a call to GC-untrack
before the trashcan begin macro. Without understanding the
trashcan code, the answers to the following questions don't make
sense.
Q. Why do we GC-untrack before the trashcan and then immediately
GC-track again afterward?
A. In the case that the base class is GC-aware, the base class
probably GC-untracks the object. If it does that using the
UNTRACK macro, this will crash when the object is already
untracked. Because we don't know what the base class does, the
only safe thing is to make sure the object is tracked when we
call the base class dealloc. But... The trashcan begin macro
requires that the object is *untracked* before it is called. So
the dance becomes:
GC untrack
trashcan begin
GC track
Q. Why did the last question say "immediately GC-track again"?
It's nowhere near immediately.
A. Because the code *used* to re-track immediately. Bad Idea.
self has a refcount of 0, and if gc ever gets its hands on it
(which can happen if any weakref callback gets invoked), it
looks like trash to gc too, and gc also tries to delete self
then. But we're already deleting self. Double deallocation is
a subtle disaster.
*/
}
static PyTypeObject *solid_base(PyTypeObject *type);
/* type test with subclassing support */
static int
type_is_subtype_base_chain(PyTypeObject *a, PyTypeObject *b)
{
do {
if (a == b)
return 1;
a = a->tp_base;
} while (a != NULL);
return (b == &PyBaseObject_Type);
}
static int
is_subtype_with_mro(PyObject *a_mro, PyTypeObject *a, PyTypeObject *b)
{
int res;
if (a_mro != NULL) {
/* Deal with multiple inheritance without recursion
by walking the MRO tuple */
Py_ssize_t i, n;
assert(PyTuple_Check(a_mro));
n = PyTuple_GET_SIZE(a_mro);
res = 0;
for (i = 0; i < n; i++) {
if (PyTuple_GET_ITEM(a_mro, i) == (PyObject *)b) {
res = 1;
break;
}
}
}
else {
/* a is not completely initialized yet; follow tp_base */
res = type_is_subtype_base_chain(a, b);
}
return res;
}
int
PyType_IsSubtype(PyTypeObject *a, PyTypeObject *b)
{
return is_subtype_with_mro(a->tp_mro, a, b);
}
/* Routines to do a method lookup in the type without looking in the
instance dictionary (so we can't use PyObject_GetAttr) but still
binding it to the instance.
Variants:
- _PyObject_LookupSpecial() returns NULL without raising an exception
when the _PyType_LookupRef() call fails;
- lookup_maybe_method() and lookup_method() are internal routines similar
to _PyObject_LookupSpecial(), but can return unbound PyFunction
to avoid temporary method object. Pass self as first argument when
unbound == 1.
*/
PyObject *
_PyObject_LookupSpecial(PyObject *self, PyObject *attr)
{
PyObject *res;
res = _PyType_LookupRef(Py_TYPE(self), attr);
if (res != NULL) {
descrgetfunc f;
if ((f = Py_TYPE(res)->tp_descr_get) != NULL) {
Py_SETREF(res, f(res, self, (PyObject *)(Py_TYPE(self))));
}
}
return res;
}
/* Steals a reference to self */
PyObject *
_PyObject_LookupSpecialMethod(PyObject *self, PyObject *attr, PyObject **self_or_null)
{
PyObject *res;
res = _PyType_LookupRef(Py_TYPE(self), attr);
if (res == NULL) {
Py_DECREF(self);
*self_or_null = NULL;
return NULL;
}
if (_PyType_HasFeature(Py_TYPE(res), Py_TPFLAGS_METHOD_DESCRIPTOR)) {
/* Avoid temporary PyMethodObject */
*self_or_null = self;
}
else {
descrgetfunc f = Py_TYPE(res)->tp_descr_get;
if (f != NULL) {
Py_SETREF(res, f(res, self, (PyObject *)(Py_TYPE(self))));
}
*self_or_null = NULL;
Py_DECREF(self);
}
return res;
}
static PyObject *
lookup_maybe_method(PyObject *self, PyObject *attr, int *unbound)
{
PyObject *res = _PyType_LookupRef(Py_TYPE(self), attr);
if (res == NULL) {
return NULL;
}
if (_PyType_HasFeature(Py_TYPE(res), Py_TPFLAGS_METHOD_DESCRIPTOR)) {
/* Avoid temporary PyMethodObject */
*unbound = 1;
}
else {
*unbound = 0;
descrgetfunc f = Py_TYPE(res)->tp_descr_get;
if (f != NULL) {
Py_SETREF(res, f(res, self, (PyObject *)(Py_TYPE(self))));
}
}
return res;
}
static PyObject *
lookup_method(PyObject *self, PyObject *attr, int *unbound)
{
PyObject *res = lookup_maybe_method(self, attr, unbound);
if (res == NULL && !PyErr_Occurred()) {
PyErr_SetObject(PyExc_AttributeError, attr);
}
return res;
}
static inline PyObject*
vectorcall_unbound(PyThreadState *tstate, int unbound, PyObject *func,
PyObject *const *args, Py_ssize_t nargs)
{
size_t nargsf = nargs;
if (!unbound) {
/* Skip self argument, freeing up args[0] to use for
* PY_VECTORCALL_ARGUMENTS_OFFSET */
args++;
nargsf = nargsf - 1 + PY_VECTORCALL_ARGUMENTS_OFFSET;
}
EVAL_CALL_STAT_INC_IF_FUNCTION(EVAL_CALL_SLOT, func);
return _PyObject_VectorcallTstate(tstate, func, args, nargsf, NULL);
}
static PyObject*
call_unbound_noarg(int unbound, PyObject *func, PyObject *self)
{
if (unbound) {
return PyObject_CallOneArg(func, self);
}
else {
return _PyObject_CallNoArgs(func);
}
}
/* A variation of PyObject_CallMethod* that uses lookup_method()
instead of PyObject_GetAttrString().
args is an argument vector of length nargs. The first element in this
vector is the special object "self" which is used for the method lookup */
static PyObject *
vectorcall_method(PyObject *name, PyObject *const *args, Py_ssize_t nargs)
{
assert(nargs >= 1);
PyThreadState *tstate = _PyThreadState_GET();
int unbound;
PyObject *self = args[0];
PyObject *func = lookup_method(self, name, &unbound);
if (func == NULL) {
return NULL;
}
PyObject *retval = vectorcall_unbound(tstate, unbound, func, args, nargs);
Py_DECREF(func);
return retval;
}
/* Clone of vectorcall_method() that returns NotImplemented
* when the lookup fails. */
static PyObject *
vectorcall_maybe(PyThreadState *tstate, PyObject *name,
PyObject *const *args, Py_ssize_t nargs)
{
assert(nargs >= 1);
int unbound;
PyObject *self = args[0];
PyObject *func = lookup_maybe_method(self, name, &unbound);
if (func == NULL) {
if (!PyErr_Occurred())
Py_RETURN_NOTIMPLEMENTED;
return NULL;
}
PyObject *retval = vectorcall_unbound(tstate, unbound, func, args, nargs);
Py_DECREF(func);
return retval;
}
/*
Method resolution order algorithm C3 described in
"A Monotonic Superclass Linearization for Dylan",
by Kim Barrett, Bob Cassel, Paul Haahr,
David A. Moon, Keith Playford, and P. Tucker Withington.
(OOPSLA 1996)
Some notes about the rules implied by C3:
No duplicate bases.
It isn't legal to repeat a class in a list of base classes.
The next three properties are the 3 constraints in "C3".
Local precedence order.
If A precedes B in C's MRO, then A will precede B in the MRO of all
subclasses of C.
Monotonicity.
The MRO of a class must be an extension without reordering of the
MRO of each of its superclasses.
Extended Precedence Graph (EPG).
Linearization is consistent if there is a path in the EPG from
each class to all its successors in the linearization. See
the paper for definition of EPG.
*/
static int
tail_contains(PyObject *tuple, int whence, PyObject *o)
{
Py_ssize_t j, size;
size = PyTuple_GET_SIZE(tuple);
for (j = whence+1; j < size; j++) {
if (PyTuple_GET_ITEM(tuple, j) == o)
return 1;
}
return 0;
}
static PyObject *
class_name(PyObject *cls)
{
PyObject *name;
if (PyObject_GetOptionalAttr(cls, &_Py_ID(__name__), &name) == 0) {
name = PyObject_Repr(cls);
}
return name;
}
static int
check_duplicates(PyObject *tuple)
{
Py_ssize_t i, j, n;
/* Let's use a quadratic time algorithm,
assuming that the bases tuples is short.
*/
n = PyTuple_GET_SIZE(tuple);
for (i = 0; i < n; i++) {
PyObject *o = PyTuple_GET_ITEM(tuple, i);
for (j = i + 1; j < n; j++) {
if (PyTuple_GET_ITEM(tuple, j) == o) {
o = class_name(o);
if (o != NULL) {
if (PyUnicode_Check(o)) {
PyErr_Format(PyExc_TypeError,
"duplicate base class %U", o);
}
else {
PyErr_SetString(PyExc_TypeError,
"duplicate base class");
}
Py_DECREF(o);
}
return -1;
}
}
}
return 0;
}
/* Raise a TypeError for an MRO order disagreement.
It's hard to produce a good error message. In the absence of better
insight into error reporting, report the classes that were candidates
to be put next into the MRO. There is some conflict between the
order in which they should be put in the MRO, but it's hard to
diagnose what constraint can't be satisfied.
*/
static void
set_mro_error(PyObject **to_merge, Py_ssize_t to_merge_size, int *remain)
{
Py_ssize_t i, n, off;
char buf[1000];
PyObject *k, *v;
PyObject *set = PyDict_New();
if (!set) return;
for (i = 0; i < to_merge_size; i++) {
PyObject *L = to_merge[i];
if (remain[i] < PyTuple_GET_SIZE(L)) {
PyObject *c = PyTuple_GET_ITEM(L, remain[i]);
if (PyDict_SetItem(set, c, Py_None) < 0) {
Py_DECREF(set);
return;
}
}
}
n = PyDict_GET_SIZE(set);
off = PyOS_snprintf(buf, sizeof(buf), "Cannot create a \
consistent method resolution order (MRO) for bases");
i = 0;
while (PyDict_Next(set, &i, &k, &v) && (size_t)off < sizeof(buf)) {
PyObject *name = class_name(k);
const char *name_str = NULL;
if (name != NULL) {
if (PyUnicode_Check(name)) {
name_str = PyUnicode_AsUTF8(name);
}
else {
name_str = "?";
}
}
if (name_str == NULL) {
Py_XDECREF(name);
Py_DECREF(set);
return;
}
off += PyOS_snprintf(buf + off, sizeof(buf) - off, " %s", name_str);
Py_XDECREF(name);
if (--n && (size_t)(off+1) < sizeof(buf)) {
buf[off++] = ',';
buf[off] = '\0';
}
}
PyErr_SetString(PyExc_TypeError, buf);
Py_DECREF(set);
}
static int
pmerge(PyObject *acc, PyObject **to_merge, Py_ssize_t to_merge_size)
{
int res = 0;
Py_ssize_t i, j, empty_cnt;
int *remain;
/* remain stores an index into each sublist of to_merge.
remain[i] is the index of the next base in to_merge[i]
that is not included in acc.
*/
remain = PyMem_New(int, to_merge_size);
if (remain == NULL) {
PyErr_NoMemory();
return -1;
}
for (i = 0; i < to_merge_size; i++)
remain[i] = 0;