#include "Python.h"

#include "pycore_initconfig.h" // _PyStatus_OK()

#include "pycore_modsupport.h" // _PyArg_NoPositional()

#include "pycore_object.h" // _PyObject_GC_TRACK()

#include "pycore_structseq.h" // PyStructSequence_InitType()

#include "pycore_tuple.h" // _PyTuple_FromArray()

#include "pycore_typeobject.h" // _PyStaticType_FiniBuiltin()

static const char visible_length_key[] = "n_sequence_fields";

static const char real_length_key[] = "n_fields";

static const char unnamed_fields_key[] = "n_unnamed_fields";

static const char match_args_key[] = "__match_args__";

const char * const PyStructSequence_UnnamedField = "unnamed field";

static Py_ssize_t

get_type_attr_as_size(PyTypeObject *tp, PyObject *name)

{

PyObject *v = PyDict_GetItemWithError(_PyType_GetDict(tp), name);

if (v == NULL && !PyErr_Occurred()) {

PyErr_Format(PyExc_TypeError,

"Missed attribute '%U' of type %s",

name, tp->tp_name);

return -1;

}

return PyLong_AsSsize_t(v);

}

#define VISIBLE_SIZE(op) Py_SIZE(op)

#define VISIBLE_SIZE_TP(tp) \

get_type_attr_as_size(tp, &_Py_ID(n_sequence_fields))

#define REAL_SIZE_TP(tp) \

get_type_attr_as_size(tp, &_Py_ID(n_fields))

#define REAL_SIZE(op) get_real_size((PyObject *)op)

#define UNNAMED_FIELDS_TP(tp) \

get_type_attr_as_size(tp, &_Py_ID(n_unnamed_fields))

#define UNNAMED_FIELDS(op) UNNAMED_FIELDS_TP(Py_TYPE(op))

static Py_ssize_t

get_real_size(PyObject *op)

{

// Compute the real size from the visible size (i.e., Py_SIZE()) and the

// number of non-sequence fields accounted for in tp_basicsize.

Py_ssize_t hidden = Py_TYPE(op)->tp_basicsize - offsetof(PyStructSequence, ob_item);

return Py_SIZE(op) + hidden / sizeof(PyObject *);

}

PyObject *

PyStructSequence_New(PyTypeObject *type)

{

PyStructSequence *obj;

Py_ssize_t size = REAL_SIZE_TP(type), i;

if (size < 0) {

return NULL;

}

Py_ssize_t vsize = VISIBLE_SIZE_TP(type);

if (vsize < 0) {

return NULL;

}

obj = PyObject_GC_NewVar(PyStructSequence, type, size);

if (obj == NULL)

return NULL;

_PyTuple_RESET_HASH_CACHE(obj);

/* Hack the size of the variable object, so invisible fields don't appear

Py_SET_SIZE(obj, vsize);

for (i = 0; i < size; i++)

obj->ob_item[i] = NULL;

return (PyObject*)obj;

}

PyStructSequence_SetItem(PyObject *op, Py_ssize_t index, PyObject *value)

{

PyTupleObject *tuple = _PyTuple_CAST(op);

assert(0 <= index);

#ifndef NDEBUG

Py_ssize_t n_fields = REAL_SIZE(op);

assert(n_fields >= 0);

assert(index < n_fields);

tuple->ob_item[index] = value;

}

PyStructSequence_GetItem(PyObject *op, Py_ssize_t index)

{

assert(0 <= index);

#ifndef NDEBUG

Py_ssize_t n_fields = REAL_SIZE(op);

assert(n_fields >= 0);

assert(index < n_fields);

return PyTuple_GET_ITEM(op, index);

}

static int

structseq_traverse(PyObject *op, visitproc visit, void *arg)

{

PyStructSequence *obj = (PyStructSequence *)op;

if (Py_TYPE(obj)->tp_flags & Py_TPFLAGS_HEAPTYPE) {

Py_VISIT(Py_TYPE(obj));

}

Py_ssize_t i, size;

size = REAL_SIZE(obj);

for (i = 0; i < size; ++i) {

Py_VISIT(obj->ob_item[i]);

}

return 0;

}

static void

structseq_dealloc(PyObject *op)

{

PyStructSequence *obj = (PyStructSequence *)op;

Py_ssize_t i, size;

PyObject_GC_UnTrack(obj);

PyTypeObject *tp = Py_TYPE(obj);

// gh-122527: We can't use REAL_SIZE_TP() or any macros that access the

// type's dictionary here, because the dictionary may have already been

// cleared by the garbage collector.

size = REAL_SIZE(obj);

for (i = 0; i < size; ++i) {

Py_XDECREF(obj->ob_item[i]);

}

PyObject_GC_Del(obj);

if (_PyType_HasFeature(tp, Py_TPFLAGS_HEAPTYPE)) {

Py_DECREF(tp);

}

}

#include "clinic/structseq.c.h"

static PyObject *

structseq_new_impl(PyTypeObject *type, PyObject *arg, PyObject *dict)

{

PyStructSequence *res = NULL;

Py_ssize_t len, min_len, max_len, i, n_unnamed_fields;

min_len = VISIBLE_SIZE_TP(type);

if (min_len < 0) {

return NULL;

}

max_len = REAL_SIZE_TP(type);

if (max_len < 0) {

return NULL;

}

n_unnamed_fields = UNNAMED_FIELDS_TP(type);

if (n_unnamed_fields < 0) {

return NULL;

}

arg = PySequence_Fast(arg, "constructor requires a sequence");

if (!arg) {

return NULL;

}

if (dict && !PyDict_Check(dict)) {

PyErr_Format(PyExc_TypeError,

"%.500s() takes a dict as second arg, if any",

type->tp_name);

Py_DECREF(arg);

return NULL;

}

len = PySequence_Fast_GET_SIZE(arg);

if (min_len != max_len) {

if (len < min_len) {

PyErr_Format(PyExc_TypeError,

"%.500s() takes an at least %zd-sequence (%zd-sequence given)",

type->tp_name, min_len, len);

Py_DECREF(arg);

return NULL;

}

if (len > max_len) {

PyErr_Format(PyExc_TypeError,

"%.500s() takes an at most %zd-sequence (%zd-sequence given)",

type->tp_name, max_len, len);

Py_DECREF(arg);

return NULL;

}

}

else {

if (len != min_len) {

PyErr_Format(PyExc_TypeError,

"%.500s() takes a %zd-sequence (%zd-sequence given)",

type->tp_name, min_len, len);

Py_DECREF(arg);

return NULL;

}

}

res = (PyStructSequence*) PyStructSequence_New(type);

if (res == NULL) {

Py_DECREF(arg);

return NULL;

}

for (i = 0; i < len; ++i) {

PyObject *v = PySequence_Fast_GET_ITEM(arg, i);

res->ob_item[i] = Py_NewRef(v);

}

Py_DECREF(arg);

if (dict != NULL && PyDict_GET_SIZE(dict) > 0) {

Py_ssize_t n_found_keys = 0;

for (i = len; i < max_len; ++i) {

PyObject *ob = NULL;

const char *name = type->tp_members[i - n_unnamed_fields].name;

if (PyDict_GetItemStringRef(dict, name, &ob) < 0) {

Py_DECREF(res);

return NULL;

}

if (ob == NULL) {

ob = Py_NewRef(Py_None);

}

else {

++n_found_keys;

}

res->ob_item[i] = ob;

}

if (PyDict_GET_SIZE(dict) > n_found_keys) {

PyErr_Format(PyExc_TypeError,

"%.500s() got duplicate or unexpected field name(s)",

type->tp_name);

Py_DECREF(res);

return NULL;

}

} else {

for (i = len; i < max_len; ++i) {

res->ob_item[i] = Py_NewRef(Py_None);

}

}

_PyObject_GC_TRACK(res);

return (PyObject*) res;

}

static PyObject *

structseq_repr(PyObject *op)

{

PyStructSequence *obj = (PyStructSequence *)op;

PyTypeObject *typ = Py_TYPE(obj);

// count 5 characters per item: "x=1, "

Py_ssize_t type_name_len = strlen(typ->tp_name);

Py_ssize_t prealloc = (type_name_len + 1

+ VISIBLE_SIZE(obj) * 5 + 1);

PyUnicodeWriter *writer = PyUnicodeWriter_Create(prealloc);

if (writer == NULL) {

return NULL;

}

// Write "typename("

if (PyUnicodeWriter_WriteUTF8(writer, typ->tp_name, type_name_len) < 0) {

goto error;

}

if (PyUnicodeWriter_WriteChar(writer, '(') < 0) {

goto error;

}

for (Py_ssize_t i=0; i < VISIBLE_SIZE(obj); i++) {

if (i > 0) {

// Write ", "

if (PyUnicodeWriter_WriteChar(writer, ',') < 0) {

goto error;

}

if (PyUnicodeWriter_WriteChar(writer, ' ') < 0) {

goto error;

}

}

// Write name

const char *name_utf8 = typ->tp_members[i].name;

if (name_utf8 == NULL) {

PyErr_Format(PyExc_SystemError,

"In structseq_repr(), member %zd name is NULL"

" for type %.500s", i, typ->tp_name);

goto error;

}

if (PyUnicodeWriter_WriteUTF8(writer, name_utf8, -1) < 0) {

goto error;

}

// Write "=" + repr(value)

if (PyUnicodeWriter_WriteChar(writer, '=') < 0) {

goto error;

}

PyObject *value = PyStructSequence_GetItem((PyObject*)obj, i);

assert(value != NULL);

if (PyUnicodeWriter_WriteRepr(writer, value) < 0) {

goto error;

}

}

if (PyUnicodeWriter_WriteChar(writer, ')') < 0) {

goto error;

}

return PyUnicodeWriter_Finish(writer);

error:

PyUnicodeWriter_Discard(writer);

return NULL;

}

static PyObject *

structseq_reduce(PyObject *op, PyObject *Py_UNUSED(ignored))

{

PyStructSequence *self = (PyStructSequence*)op;

PyObject* tup = NULL;

PyObject* dict = NULL;

PyObject* result;

Py_ssize_t n_fields, n_visible_fields, n_unnamed_fields, i;

n_fields = REAL_SIZE(self);

if (n_fields < 0) {

return NULL;

}

n_visible_fields = VISIBLE_SIZE(self);

n_unnamed_fields = UNNAMED_FIELDS(self);

if (n_unnamed_fields < 0) {

return NULL;

}

tup = _PyTuple_FromArray(self->ob_item, n_visible_fields);

if (!tup)

goto error;

dict = PyDict_New();

if (!dict)

goto error;

for (i = n_visible_fields; i < n_fields; i++) {

const char *n = Py_TYPE(self)->tp_members[i-n_unnamed_fields].name;

if (PyDict_SetItemString(dict, n, self->ob_item[i]) < 0)

goto error;

}

result = Py_BuildValue("(O(OO))", Py_TYPE(self), tup, dict);

Py_DECREF(tup);

Py_DECREF(dict);

return result;

error:

Py_XDECREF(tup);

Py_XDECREF(dict);

return NULL;

}

static PyObject *

structseq_replace(PyObject *op, PyObject *args, PyObject *kwargs)

{

PyStructSequence *self = (PyStructSequence*)op;

PyStructSequence *result = NULL;

Py_ssize_t n_fields, n_unnamed_fields, i;

if (!_PyArg_NoPositional("__replace__", args)) {

return NULL;

}

n_fields = REAL_SIZE(self);

if (n_fields < 0) {

return NULL;

}

n_unnamed_fields = UNNAMED_FIELDS(self);

if (n_unnamed_fields < 0) {

return NULL;

}

if (n_unnamed_fields > 0) {

PyErr_Format(PyExc_TypeError,

"__replace__() is not supported for %.500s "

"because it has unnamed field(s)",

Py_TYPE(self)->tp_name);

return NULL;

}

result = (PyStructSequence *) PyStructSequence_New(Py_TYPE(self));

if (!result) {

return NULL;

}

if (kwargs != NULL) {

// We do not support types with unnamed fields, so we can iterate over

// i >= n_visible_fields case without slicing with (i - n_unnamed_fields).

for (i = 0; i < n_fields; ++i) {

PyObject *ob;

if (PyDict_PopString(kwargs, Py_TYPE(self)->tp_members[i].name,

&ob) < 0) {

goto error;

}

if (ob == NULL) {

ob = Py_NewRef(self->ob_item[i]);

}

result->ob_item[i] = ob;

}

// Check if there are any unexpected fields.

if (PyDict_GET_SIZE(kwargs) > 0) {

PyObject *names = PyDict_Keys(kwargs);

if (names) {

PyErr_Format(PyExc_TypeError, "Got unexpected field name(s): %R", names);

Py_DECREF(names);

}

goto error;

}

}

else

{

// Just create a copy of the original.

for (i = 0; i < n_fields; ++i) {

result->ob_item[i] = Py_NewRef(self->ob_item[i]);

}

}

_PyObject_GC_TRACK(result);

return (PyObject *)result;

error:

Py_DECREF(result);

return NULL;

}

static PyMethodDef structseq_methods[] = {

{"__reduce__", structseq_reduce, METH_NOARGS, NULL},

{"__replace__", _PyCFunction_CAST(structseq_replace), METH_VARARGS | METH_KEYWORDS,

PyDoc_STR("__replace__($self, /, **changes)\n--\n\n"

"Return a copy of the structure with new values for the specified fields.")},

{NULL, NULL} // sentinel

};

static Py_ssize_t

count_members(PyStructSequence_Desc *desc, Py_ssize_t *n_unnamed_members) {

Py_ssize_t i;

*n_unnamed_members = 0;

for (i = 0; desc->fields[i].name != NULL; ++i) {

if (desc->fields[i].name == PyStructSequence_UnnamedField) {

(*n_unnamed_members)++;

}

}

return i;

}

static int

initialize_structseq_dict(PyStructSequence_Desc *desc, PyObject* dict,

Py_ssize_t n_members, Py_ssize_t n_unnamed_members) {

PyObject *v;

#define SET_DICT_FROM_SIZE(key, value) \

do { \

v = PyLong_FromSsize_t(value); \

if (v == NULL) { \

return -1; \

} \

if (PyDict_SetItemString(dict, key, v) < 0) { \

Py_DECREF(v); \

return -1; \

} \

Py_DECREF(v); \

} while (0)

SET_DICT_FROM_SIZE(visible_length_key, desc->n_in_sequence);

SET_DICT_FROM_SIZE(real_length_key, n_members);

SET_DICT_FROM_SIZE(unnamed_fields_key, n_unnamed_members);

// Prepare and set __match_args__

Py_ssize_t i, k;

PyObject* keys = PyTuple_New(desc->n_in_sequence);

if (keys == NULL) {

return -1;

}

for (i = k = 0; i < desc->n_in_sequence; ++i) {

if (desc->fields[i].name == PyStructSequence_UnnamedField) {

continue;

}

PyObject* new_member = PyUnicode_FromString(desc->fields[i].name);

if (new_member == NULL) {

goto error;

}

PyTuple_SET_ITEM(keys, k, new_member);

k++;

}

if (_PyTuple_Resize(&keys, k) == -1) {

goto error;

}

if (PyDict_SetItemString(dict, match_args_key, keys) < 0) {

goto error;

}

Py_DECREF(keys);

return 0;

error:

Py_DECREF(keys);

return -1;

}

static PyMemberDef *

initialize_members(PyStructSequence_Desc *desc,

Py_ssize_t n_members, Py_ssize_t n_unnamed_members)

{

PyMemberDef *members;

members = PyMem_NEW(PyMemberDef, n_members - n_unnamed_members + 1);

if (members == NULL) {

PyErr_NoMemory();

return NULL;

}

Py_ssize_t i, k;

for (i = k = 0; i < n_members; ++i) {

if (desc->fields[i].name == PyStructSequence_UnnamedField) {

continue;

}

/* The names and docstrings in these MemberDefs are statically */

/* allocated so it is expected that they'll outlive the MemberDef */

members[k].name = desc->fields[i].name;

members[k].type = _Py_T_OBJECT;

members[k].offset = offsetof(PyStructSequence, ob_item)

+ i * sizeof(PyObject*);

members[k].flags = Py_READONLY;

members[k].doc = desc->fields[i].doc;

k++;

}

members[k].name = NULL;

return members;

}

static void

initialize_static_fields(PyTypeObject *type, PyStructSequence_Desc *desc,

PyMemberDef *tp_members, Py_ssize_t n_members,

unsigned long tp_flags)

{

type->tp_name = desc->name;

// Account for hidden members in tp_basicsize because they are not

// included in the variable size.

Py_ssize_t n_hidden = n_members - desc->n_in_sequence;

type->tp_basicsize = sizeof(PyStructSequence) + (n_hidden - 1) * sizeof(PyObject *);

type->tp_itemsize = sizeof(PyObject *);

type->tp_dealloc = structseq_dealloc;

type->tp_repr = structseq_repr;

type->tp_doc = desc->doc;

type->tp_base = &PyTuple_Type;

type->tp_methods = structseq_methods;

type->tp_new = structseq_new;

type->tp_flags = Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC | tp_flags;

type->tp_traverse = structseq_traverse;

type->tp_members = tp_members;

}

static int

initialize_static_type(PyTypeObject *type, PyStructSequence_Desc *desc,

Py_ssize_t n_members, Py_ssize_t n_unnamed_members) {

/* initialize_static_fields() should have been called already. */

if (PyType_Ready(type) < 0) {

return -1;

}

Py_INCREF(type);

if (initialize_structseq_dict(

desc, _PyType_GetDict(type), n_members, n_unnamed_members) < 0) {

Py_DECREF(type);

return -1;

}

return 0;

}

_PyStructSequence_InitBuiltinWithFlags(PyInterpreterState *interp,

PyTypeObject *type,

PyStructSequence_Desc *desc,

unsigned long tp_flags)

{

if (Py_TYPE(type) == NULL) {

Py_SET_TYPE(type, &PyType_Type);

}

Py_ssize_t n_unnamed_members;

Py_ssize_t n_members = count_members(desc, &n_unnamed_members);

PyMemberDef *members = NULL;

if ((type->tp_flags & Py_TPFLAGS_READY) == 0) {

assert(type->tp_name == NULL);

assert(type->tp_members == NULL);

assert(type->tp_base == NULL);

members = initialize_members(desc, n_members, n_unnamed_members);

if (members == NULL) {

goto error;

}

initialize_static_fields(type, desc, members, n_members, tp_flags);

_Py_SetImmortal((PyObject *)type);

}

#ifndef NDEBUG

else {

// Ensure that the type was initialized.

assert(type->tp_name != NULL);

assert(type->tp_members != NULL);

assert(type->tp_base == &PyTuple_Type);

assert((type->tp_flags & _Py_TPFLAGS_STATIC_BUILTIN));

assert(_Py_IsImmortal(type));

}

if (_PyStaticType_InitBuiltin(interp, type) < 0) {

PyErr_Format(PyExc_RuntimeError,

"Can't initialize builtin type %s",

desc->name);

goto error;

}

if (initialize_structseq_dict(

desc, _PyType_GetDict(type), n_members, n_unnamed_members) < 0)

{

goto error;

}

return 0;

error:

if (members != NULL) {

PyMem_Free(members);

}

return -1;

}

PyStructSequence_InitType2(PyTypeObject *type, PyStructSequence_Desc *desc)

{

PyMemberDef *members;

Py_ssize_t n_members, n_unnamed_members;

#ifdef Py_TRACE_REFS

/* if the type object was traced, remove it first

PyInterpreterState *interp = _PyInterpreterState_GET();

if (_PyRefchain_IsTraced(interp, (PyObject *)type)) {

_Py_ForgetReference((PyObject *)type);

}

/* PyTypeObject has already been initialized */

if (Py_REFCNT(type) != 0) {

PyErr_BadInternalCall();

return -1;

}

n_members = count_members(desc, &n_unnamed_members);

members = initialize_members(desc, n_members, n_unnamed_members);

if (members == NULL) {

return -1;

}

initialize_static_fields(type, desc, members, n_members, 0);

if (initialize_static_type(type, desc, n_members, n_unnamed_members) < 0) {

PyMem_Free(members);

return -1;

}

return 0;

}

PyStructSequence_InitType(PyTypeObject *type, PyStructSequence_Desc *desc)

{

(void)PyStructSequence_InitType2(type, desc);

}

_PyStructSequence_FiniBuiltin(PyInterpreterState *interp, PyTypeObject *type)

{

// Ensure that the type is initialized

assert(type->tp_name != NULL);

assert(type->tp_base == &PyTuple_Type);

assert((type->tp_flags & _Py_TPFLAGS_STATIC_BUILTIN));

assert(_Py_IsImmortal(type));

// Cannot delete a type if it still has subclasses

if (_PyType_HasSubclasses(type)) {

// XXX Shouldn't this be an error?

return;

}

_PyStaticType_FiniBuiltin(interp, type);

if (_Py_IsMainInterpreter(interp)) {

// Undo _PyStructSequence_InitBuiltinWithFlags().

type->tp_name = NULL;

PyMem_Free(type->tp_members);

type->tp_members = NULL;

type->tp_base = NULL;

}

}

PyTypeObject *

_PyStructSequence_NewType(PyStructSequence_Desc *desc, unsigned long tp_flags)

{

PyMemberDef *members;

PyTypeObject *type;

PyType_Slot slots[8];

PyType_Spec spec;

Py_ssize_t n_members, n_unnamed_members;

/* Initialize MemberDefs */

n_members = count_members(desc, &n_unnamed_members);

members = initialize_members(desc, n_members, n_unnamed_members);

if (members == NULL) {

return NULL;

}

/* Initialize Slots */

slots[0] = (PyType_Slot){Py_tp_dealloc, structseq_dealloc};

slots[1] = (PyType_Slot){Py_tp_repr, structseq_repr};

slots[2] = (PyType_Slot){Py_tp_doc, (void *)desc->doc};

slots[3] = (PyType_Slot){Py_tp_methods, structseq_methods};

slots[4] = (PyType_Slot){Py_tp_new, structseq_new};

slots[5] = (PyType_Slot){Py_tp_members, members};

slots[6] = (PyType_Slot){Py_tp_traverse, structseq_traverse};

slots[7] = (PyType_Slot){0, 0};

/* Initialize Spec */

/* The name in this PyType_Spec is statically allocated so it is */

/* expected that it'll outlive the PyType_Spec */

spec.name = desc->name;

Py_ssize_t hidden = n_members - desc->n_in_sequence;

spec.basicsize = (int)(sizeof(PyStructSequence) + (hidden - 1) * sizeof(PyObject *));

spec.itemsize = sizeof(PyObject *);

spec.flags = Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC | tp_flags;

spec.slots = slots;

type = (PyTypeObject *)PyType_FromSpecWithBases(&spec, (PyObject *)&PyTuple_Type);

PyMem_Free(members);

if (type == NULL) {

return NULL;

}

if (initialize_structseq_dict(

desc, _PyType_GetDict(type), n_members, n_unnamed_members) < 0) {

Py_DECREF(type);

return NULL;

}

return type;

}

PyTypeObject *

PyStructSequence_NewType(PyStructSequence_Desc *desc)

{

return _PyStructSequence_NewType(desc, 0);

}