cpython/Objects/call.c

972 lines
27 KiB
C
Raw Normal View History

#include "Python.h"
#include "pycore_call.h" // _PyObject_CallNoArgTstate()
#include "pycore_ceval.h" // _PyEval_EvalFrame()
#include "pycore_object.h" // _PyObject_GC_TRACK()
#include "pycore_pyerrors.h" // _PyErr_Occurred()
#include "pycore_pystate.h" // _PyThreadState_GET()
#include "pycore_tuple.h" // _PyTuple_ITEMS()
#include "frameobject.h" // _PyFrame_New_NoTrack()
static PyObject *const *
_PyStack_UnpackDict(PyThreadState *tstate,
PyObject *const *args, Py_ssize_t nargs,
PyObject *kwargs, PyObject **p_kwnames);
static void
_PyStack_UnpackDict_Free(PyObject *const *stack, Py_ssize_t nargs,
PyObject *kwnames);
static PyObject *
null_error(PyThreadState *tstate)
{
if (!_PyErr_Occurred(tstate)) {
_PyErr_SetString(tstate, PyExc_SystemError,
"null argument to internal routine");
}
return NULL;
}
PyObject*
_Py_CheckFunctionResult(PyThreadState *tstate, PyObject *callable,
PyObject *result, const char *where)
{
assert((callable != NULL) ^ (where != NULL));
if (result == NULL) {
if (!_PyErr_Occurred(tstate)) {
if (callable)
_PyErr_Format(tstate, PyExc_SystemError,
"%R returned NULL without setting an exception",
callable);
else
_PyErr_Format(tstate, PyExc_SystemError,
"%s returned NULL without setting an exception",
where);
#ifdef Py_DEBUG
/* Ensure that the bug is caught in debug mode.
Py_FatalError() logs the SystemError exception raised above. */
Py_FatalError("a function returned NULL without setting an exception");
#endif
return NULL;
}
}
else {
if (_PyErr_Occurred(tstate)) {
Py_DECREF(result);
if (callable) {
_PyErr_FormatFromCauseTstate(
tstate, PyExc_SystemError,
"%R returned a result with an exception set", callable);
}
else {
_PyErr_FormatFromCauseTstate(
tstate, PyExc_SystemError,
"%s returned a result with an exception set", where);
}
#ifdef Py_DEBUG
/* Ensure that the bug is caught in debug mode.
Py_FatalError() logs the SystemError exception raised above. */
Py_FatalError("a function returned a result with an exception set");
#endif
return NULL;
}
}
return result;
}
int
_Py_CheckSlotResult(PyObject *obj, const char *slot_name, int success)
{
PyThreadState *tstate = _PyThreadState_GET();
if (!success) {
if (!_PyErr_Occurred(tstate)) {
_Py_FatalErrorFormat(__func__,
"Slot %s of type %s failed "
"without setting an exception",
slot_name, Py_TYPE(obj)->tp_name);
}
}
else {
if (_PyErr_Occurred(tstate)) {
_Py_FatalErrorFormat(__func__,
"Slot %s of type %s succeeded "
"with an exception set",
slot_name, Py_TYPE(obj)->tp_name);
}
}
return 1;
}
/* --- Core PyObject call functions ------------------------------- */
/* Call a callable Python object without any arguments */
PyObject *
PyObject_CallNoArgs(PyObject *func)
{
PyThreadState *tstate = _PyThreadState_GET();
return _PyObject_CallNoArgTstate(tstate, func);
}
PyObject *
_PyObject_FastCallDictTstate(PyThreadState *tstate, PyObject *callable,
PyObject *const *args, size_t nargsf,
PyObject *kwargs)
{
assert(callable != NULL);
/* PyObject_VectorcallDict() 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));
Py_ssize_t nargs = PyVectorcall_NARGS(nargsf);
assert(nargs >= 0);
assert(nargs == 0 || args != NULL);
assert(kwargs == NULL || PyDict_Check(kwargs));
vectorcallfunc func = PyVectorcall_Function(callable);
if (func == NULL) {
/* Use tp_call instead */
return _PyObject_MakeTpCall(tstate, callable, args, nargs, kwargs);
}
PyObject *res;
if (kwargs == NULL || PyDict_GET_SIZE(kwargs) == 0) {
res = func(callable, args, nargsf, NULL);
}
else {
PyObject *kwnames;
PyObject *const *newargs;
newargs = _PyStack_UnpackDict(tstate,
args, nargs,
kwargs, &kwnames);
if (newargs == NULL) {
return NULL;
}
res = func(callable, newargs,
nargs | PY_VECTORCALL_ARGUMENTS_OFFSET, kwnames);
_PyStack_UnpackDict_Free(newargs, nargs, kwnames);
}
return _Py_CheckFunctionResult(tstate, callable, res, NULL);
}
PyObject *
PyObject_VectorcallDict(PyObject *callable, PyObject *const *args,
size_t nargsf, PyObject *kwargs)
{
PyThreadState *tstate = _PyThreadState_GET();
return _PyObject_FastCallDictTstate(tstate, callable, args, nargsf, kwargs);
}
PyObject *
_PyObject_MakeTpCall(PyThreadState *tstate, PyObject *callable,
PyObject *const *args, Py_ssize_t nargs,
PyObject *keywords)
{
assert(nargs >= 0);
assert(nargs == 0 || args != NULL);
assert(keywords == NULL || PyTuple_Check(keywords) || PyDict_Check(keywords));
/* Slow path: build a temporary tuple for positional arguments and a
* temporary dictionary for keyword arguments (if any) */
ternaryfunc call = Py_TYPE(callable)->tp_call;
if (call == NULL) {
_PyErr_Format(tstate, PyExc_TypeError,
"'%.200s' object is not callable",
Py_TYPE(callable)->tp_name);
return NULL;
}
PyObject *argstuple = _PyTuple_FromArray(args, nargs);
if (argstuple == NULL) {
return NULL;
}
PyObject *kwdict;
if (keywords == NULL || PyDict_Check(keywords)) {
kwdict = keywords;
}
else {
if (PyTuple_GET_SIZE(keywords)) {
assert(args != NULL);
kwdict = _PyStack_AsDict(args + nargs, keywords);
if (kwdict == NULL) {
Py_DECREF(argstuple);
return NULL;
}
}
else {
keywords = kwdict = NULL;
}
}
PyObject *result = NULL;
if (_Py_EnterRecursiveCall(tstate, " while calling a Python object") == 0)
{
result = call(callable, argstuple, kwdict);
_Py_LeaveRecursiveCall(tstate);
}
Py_DECREF(argstuple);
if (kwdict != keywords) {
Py_DECREF(kwdict);
}
return _Py_CheckFunctionResult(tstate, callable, result, NULL);
}
PyObject *
PyVectorcall_Call(PyObject *callable, PyObject *tuple, PyObject *kwargs)
{
PyThreadState *tstate = _PyThreadState_GET();
vectorcallfunc func;
/* get vectorcallfunc as in PyVectorcall_Function, but without
* the Py_TPFLAGS_HAVE_VECTORCALL check */
Py_ssize_t offset = Py_TYPE(callable)->tp_vectorcall_offset;
if (offset <= 0) {
_PyErr_Format(tstate, PyExc_TypeError,
"'%.200s' object does not support vectorcall",
Py_TYPE(callable)->tp_name);
return NULL;
}
memcpy(&func, (char *) callable + offset, sizeof(func));
if (func == NULL) {
_PyErr_Format(tstate, PyExc_TypeError,
"'%.200s' object does not support vectorcall",
Py_TYPE(callable)->tp_name);
return NULL;
}
Py_ssize_t nargs = PyTuple_GET_SIZE(tuple);
/* Fast path for no keywords */
if (kwargs == NULL || PyDict_GET_SIZE(kwargs) == 0) {
return func(callable, _PyTuple_ITEMS(tuple), nargs, NULL);
}
/* Convert arguments & call */
PyObject *const *args;
PyObject *kwnames;
args = _PyStack_UnpackDict(tstate,
_PyTuple_ITEMS(tuple), nargs,
kwargs, &kwnames);
if (args == NULL) {
return NULL;
}
PyObject *result = func(callable, args,
nargs | PY_VECTORCALL_ARGUMENTS_OFFSET, kwnames);
_PyStack_UnpackDict_Free(args, nargs, kwnames);
return _Py_CheckFunctionResult(tstate, callable, result, NULL);
}
PyObject *
_PyObject_Call(PyThreadState *tstate, PyObject *callable,
PyObject *args, PyObject *kwargs)
{
ternaryfunc call;
PyObject *result;
/* PyObject_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));
assert(PyTuple_Check(args));
assert(kwargs == NULL || PyDict_Check(kwargs));
if (PyVectorcall_Function(callable) != NULL) {
return PyVectorcall_Call(callable, args, kwargs);
}
else {
call = Py_TYPE(callable)->tp_call;
if (call == NULL) {
_PyErr_Format(tstate, PyExc_TypeError,
"'%.200s' object is not callable",
Py_TYPE(callable)->tp_name);
return NULL;
}
if (_Py_EnterRecursiveCall(tstate, " while calling a Python object")) {
return NULL;
}
result = (*call)(callable, args, kwargs);
_Py_LeaveRecursiveCall(tstate);
return _Py_CheckFunctionResult(tstate, callable, result, NULL);
}
}
PyObject *
PyObject_Call(PyObject *callable, PyObject *args, PyObject *kwargs)
{
PyThreadState *tstate = _PyThreadState_GET();
return _PyObject_Call(tstate, callable, args, kwargs);
}
PyObject *
PyCFunction_Call(PyObject *callable, PyObject *args, PyObject *kwargs)
{
PyThreadState *tstate = _PyThreadState_GET();
return _PyObject_Call(tstate, callable, args, kwargs);
}
/* --- PyFunction call functions ---------------------------------- */
PyObject *
_PyFunction_Vectorcall(PyObject *func, PyObject* const* stack,
size_t nargsf, PyObject *kwnames)
{
assert(PyFunction_Check(func));
PyFrameConstructor *f = PyFunction_AS_FRAME_CONSTRUCTOR(func);
Py_ssize_t nargs = PyVectorcall_NARGS(nargsf);
assert(nargs >= 0);
PyThreadState *tstate = _PyThreadState_GET();
assert(nargs == 0 || stack != NULL);
if (((PyCodeObject *)f->fc_code)->co_flags & CO_OPTIMIZED) {
return _PyEval_Vector(tstate, f, NULL, stack, nargs, kwnames);
}
else {
return _PyEval_Vector(tstate, f, f->fc_globals, stack, nargs, kwnames);
}
}
/* --- More complex call functions -------------------------------- */
/* External interface to call any callable object.
The args must be a tuple or NULL. The kwargs must be a dict or NULL. */
PyObject *
PyEval_CallObjectWithKeywords(PyObject *callable,
PyObject *args, PyObject *kwargs)
{
PyThreadState *tstate = _PyThreadState_GET();
#ifdef Py_DEBUG
/* PyEval_CallObjectWithKeywords() must not be called with an exception
set. It raises a new exception if parameters are invalid or if
PyTuple_New() fails, and so the original exception is lost. */
assert(!_PyErr_Occurred(tstate));
#endif
if (args != NULL && !PyTuple_Check(args)) {
_PyErr_SetString(tstate, PyExc_TypeError,
"argument list must be a tuple");
return NULL;
}
if (kwargs != NULL && !PyDict_Check(kwargs)) {
_PyErr_SetString(tstate, PyExc_TypeError,
"keyword list must be a dictionary");
return NULL;
}
if (args == NULL) {
return _PyObject_FastCallDictTstate(tstate, callable, NULL, 0, kwargs);
}
else {
return _PyObject_Call(tstate, callable, args, kwargs);
}
}
PyObject *
PyObject_CallObject(PyObject *callable, PyObject *args)
{
PyThreadState *tstate = _PyThreadState_GET();
assert(!_PyErr_Occurred(tstate));
if (args == NULL) {
return _PyObject_CallNoArgTstate(tstate, callable);
}
if (!PyTuple_Check(args)) {
_PyErr_SetString(tstate, PyExc_TypeError,
"argument list must be a tuple");
return NULL;
}
return _PyObject_Call(tstate, callable, args, NULL);
}
/* Call callable(obj, *args, **kwargs). */
PyObject *
_PyObject_Call_Prepend(PyThreadState *tstate, PyObject *callable,
PyObject *obj, PyObject *args, PyObject *kwargs)
{
assert(PyTuple_Check(args));
PyObject *small_stack[_PY_FASTCALL_SMALL_STACK];
PyObject **stack;
Py_ssize_t argcount = PyTuple_GET_SIZE(args);
if (argcount + 1 <= (Py_ssize_t)Py_ARRAY_LENGTH(small_stack)) {
stack = small_stack;
}
else {
stack = PyMem_Malloc((argcount + 1) * sizeof(PyObject *));
if (stack == NULL) {
PyErr_NoMemory();
return NULL;
}
}
/* use borrowed references */
stack[0] = obj;
memcpy(&stack[1],
_PyTuple_ITEMS(args),
argcount * sizeof(PyObject *));
PyObject *result = _PyObject_FastCallDictTstate(tstate, callable,
stack, argcount + 1,
kwargs);
if (stack != small_stack) {
PyMem_Free(stack);
}
return result;
}
/* --- Call with a format string ---------------------------------- */
static PyObject *
_PyObject_CallFunctionVa(PyThreadState *tstate, PyObject *callable,
const char *format, va_list va, int is_size_t)
{
PyObject* small_stack[_PY_FASTCALL_SMALL_STACK];
const Py_ssize_t small_stack_len = Py_ARRAY_LENGTH(small_stack);
PyObject **stack;
Py_ssize_t nargs, i;
PyObject *result;
if (callable == NULL) {
return null_error(tstate);
}
if (!format || !*format) {
return _PyObject_CallNoArgTstate(tstate, callable);
}
if (is_size_t) {
stack = _Py_VaBuildStack_SizeT(small_stack, small_stack_len,
format, va, &nargs);
}
else {
stack = _Py_VaBuildStack(small_stack, small_stack_len,
format, va, &nargs);
}
if (stack == NULL) {
return NULL;
}
if (nargs == 1 && PyTuple_Check(stack[0])) {
/* Special cases for backward compatibility:
- PyObject_CallFunction(func, "O", tuple) calls func(*tuple)
- PyObject_CallFunction(func, "(OOO)", arg1, arg2, arg3) calls
func(*(arg1, arg2, arg3)): func(arg1, arg2, arg3) */
PyObject *args = stack[0];
result = _PyObject_VectorcallTstate(tstate, callable,
_PyTuple_ITEMS(args),
PyTuple_GET_SIZE(args),
NULL);
}
else {
result = _PyObject_VectorcallTstate(tstate, callable,
stack, nargs, NULL);
}
for (i = 0; i < nargs; ++i) {
Py_DECREF(stack[i]);
}
if (stack != small_stack) {
PyMem_Free(stack);
}
return result;
}
PyObject *
PyObject_CallFunction(PyObject *callable, const char *format, ...)
{
va_list va;
PyObject *result;
PyThreadState *tstate = _PyThreadState_GET();
va_start(va, format);
result = _PyObject_CallFunctionVa(tstate, callable, format, va, 0);
va_end(va);
return result;
}
/* PyEval_CallFunction is exact copy of PyObject_CallFunction.
* This function is kept for backward compatibility.
*/
PyObject *
PyEval_CallFunction(PyObject *callable, const char *format, ...)
{
va_list va;
PyObject *result;
PyThreadState *tstate = _PyThreadState_GET();
va_start(va, format);
result = _PyObject_CallFunctionVa(tstate, callable, format, va, 0);
va_end(va);
return result;
}
PyObject *
_PyObject_CallFunction_SizeT(PyObject *callable, const char *format, ...)
{
PyThreadState *tstate = _PyThreadState_GET();
va_list va;
va_start(va, format);
PyObject *result = _PyObject_CallFunctionVa(tstate, callable, format, va, 1);
va_end(va);
return result;
}
static PyObject*
callmethod(PyThreadState *tstate, PyObject* callable, const char *format, va_list va, int is_size_t)
{
assert(callable != NULL);
if (!PyCallable_Check(callable)) {
_PyErr_Format(tstate, PyExc_TypeError,
"attribute of type '%.200s' is not callable",
Py_TYPE(callable)->tp_name);
return NULL;
}
return _PyObject_CallFunctionVa(tstate, callable, format, va, is_size_t);
}
PyObject *
PyObject_CallMethod(PyObject *obj, const char *name, const char *format, ...)
{
PyThreadState *tstate = _PyThreadState_GET();
if (obj == NULL || name == NULL) {
return null_error(tstate);
}
PyObject *callable = PyObject_GetAttrString(obj, name);
if (callable == NULL) {
return NULL;
}
va_list va;
va_start(va, format);
PyObject *retval = callmethod(tstate, callable, format, va, 0);
va_end(va);
Py_DECREF(callable);
return retval;
}
/* PyEval_CallMethod is exact copy of PyObject_CallMethod.
* This function is kept for backward compatibility.
*/
PyObject *
PyEval_CallMethod(PyObject *obj, const char *name, const char *format, ...)
{
PyThreadState *tstate = _PyThreadState_GET();
if (obj == NULL || name == NULL) {
return null_error(tstate);
}
PyObject *callable = PyObject_GetAttrString(obj, name);
if (callable == NULL) {
return NULL;
}
va_list va;
va_start(va, format);
PyObject *retval = callmethod(tstate, callable, format, va, 0);
va_end(va);
Py_DECREF(callable);
return retval;
}
PyObject *
_PyObject_CallMethodId(PyObject *obj, _Py_Identifier *name,
const char *format, ...)
{
PyThreadState *tstate = _PyThreadState_GET();
if (obj == NULL || name == NULL) {
return null_error(tstate);
}
PyObject *callable = _PyObject_GetAttrId(obj, name);
if (callable == NULL) {
return NULL;
}
va_list va;
va_start(va, format);
PyObject *retval = callmethod(tstate, callable, format, va, 0);
va_end(va);
Py_DECREF(callable);
return retval;
}
PyObject *
_PyObject_CallMethod_SizeT(PyObject *obj, const char *name,
const char *format, ...)
{
PyThreadState *tstate = _PyThreadState_GET();
if (obj == NULL || name == NULL) {
return null_error(tstate);
}
PyObject *callable = PyObject_GetAttrString(obj, name);
if (callable == NULL) {
return NULL;
}
va_list va;
va_start(va, format);
PyObject *retval = callmethod(tstate, callable, format, va, 1);
va_end(va);
Py_DECREF(callable);
return retval;
}
PyObject *
_PyObject_CallMethodId_SizeT(PyObject *obj, _Py_Identifier *name,
const char *format, ...)
{
PyThreadState *tstate = _PyThreadState_GET();
if (obj == NULL || name == NULL) {
return null_error(tstate);
}
PyObject *callable = _PyObject_GetAttrId(obj, name);
if (callable == NULL) {
return NULL;
}
va_list va;
va_start(va, format);
PyObject *retval = callmethod(tstate, callable, format, va, 1);
va_end(va);
Py_DECREF(callable);
return retval;
}
/* --- Call with "..." arguments ---------------------------------- */
static PyObject *
object_vacall(PyThreadState *tstate, PyObject *base,
PyObject *callable, va_list vargs)
{
PyObject *small_stack[_PY_FASTCALL_SMALL_STACK];
PyObject **stack;
Py_ssize_t nargs;
PyObject *result;
Py_ssize_t i;
va_list countva;
if (callable == NULL) {
return null_error(tstate);
}
/* Count the number of arguments */
va_copy(countva, vargs);
nargs = base ? 1 : 0;
while (1) {
PyObject *arg = va_arg(countva, PyObject *);
if (arg == NULL) {
break;
}
nargs++;
}
va_end(countva);
/* Copy arguments */
if (nargs <= (Py_ssize_t)Py_ARRAY_LENGTH(small_stack)) {
stack = small_stack;
}
else {
stack = PyMem_Malloc(nargs * sizeof(stack[0]));
if (stack == NULL) {
PyErr_NoMemory();
return NULL;
}
}
i = 0;
if (base) {
stack[i++] = base;
}
for (; i < nargs; ++i) {
stack[i] = va_arg(vargs, PyObject *);
}
/* Call the function */
result = _PyObject_VectorcallTstate(tstate, callable, stack, nargs, NULL);
if (stack != small_stack) {
PyMem_Free(stack);
}
return result;
}
PyObject *
PyObject_VectorcallMethod(PyObject *name, PyObject *const *args,
size_t nargsf, PyObject *kwnames)
{
assert(name != NULL);
assert(args != NULL);
assert(PyVectorcall_NARGS(nargsf) >= 1);
PyThreadState *tstate = _PyThreadState_GET();
PyObject *callable = NULL;
/* Use args[0] as "self" argument */
int unbound = _PyObject_GetMethod(args[0], name, &callable);
if (callable == NULL) {
return NULL;
}
if (unbound) {
/* We must remove PY_VECTORCALL_ARGUMENTS_OFFSET since
* that would be interpreted as allowing to change args[-1] */
nargsf &= ~PY_VECTORCALL_ARGUMENTS_OFFSET;
}
else {
/* Skip "self". We can keep PY_VECTORCALL_ARGUMENTS_OFFSET since
* args[-1] in the onward call is args[0] here. */
args++;
nargsf--;
}
PyObject *result = _PyObject_VectorcallTstate(tstate, callable,
args, nargsf, kwnames);
Py_DECREF(callable);
return result;
}
PyObject *
PyObject_CallMethodObjArgs(PyObject *obj, PyObject *name, ...)
{
PyThreadState *tstate = _PyThreadState_GET();
if (obj == NULL || name == NULL) {
return null_error(tstate);
}
PyObject *callable = NULL;
int is_method = _PyObject_GetMethod(obj, name, &callable);
if (callable == NULL) {
return NULL;
}
obj = is_method ? obj : NULL;
va_list vargs;
va_start(vargs, name);
PyObject *result = object_vacall(tstate, obj, callable, vargs);
va_end(vargs);
Py_DECREF(callable);
return result;
}
PyObject *
_PyObject_CallMethodIdObjArgs(PyObject *obj,
struct _Py_Identifier *name, ...)
{
PyThreadState *tstate = _PyThreadState_GET();
if (obj == NULL || name == NULL) {
return null_error(tstate);
}
PyObject *oname = _PyUnicode_FromId(name); /* borrowed */
if (!oname) {
return NULL;
}
PyObject *callable = NULL;
int is_method = _PyObject_GetMethod(obj, oname, &callable);
if (callable == NULL) {
return NULL;
}
obj = is_method ? obj : NULL;
va_list vargs;
va_start(vargs, name);
PyObject *result = object_vacall(tstate, obj, callable, vargs);
va_end(vargs);
Py_DECREF(callable);
return result;
}
PyObject *
PyObject_CallFunctionObjArgs(PyObject *callable, ...)
{
PyThreadState *tstate = _PyThreadState_GET();
va_list vargs;
PyObject *result;
va_start(vargs, callable);
result = object_vacall(tstate, NULL, callable, vargs);
va_end(vargs);
return result;
}
/* --- PyStack functions ------------------------------------------ */
PyObject *
_PyStack_AsDict(PyObject *const *values, PyObject *kwnames)
{
Py_ssize_t nkwargs;
PyObject *kwdict;
Py_ssize_t i;
assert(kwnames != NULL);
nkwargs = PyTuple_GET_SIZE(kwnames);
kwdict = _PyDict_NewPresized(nkwargs);
if (kwdict == NULL) {
return NULL;
}
for (i = 0; i < nkwargs; i++) {
PyObject *key = PyTuple_GET_ITEM(kwnames, i);
PyObject *value = *values++;
/* If key already exists, replace it with the new value */
if (PyDict_SetItem(kwdict, key, value)) {
Py_DECREF(kwdict);
return NULL;
}
}
return kwdict;
}
/* Convert (args, nargs, kwargs: dict) into a (stack, nargs, kwnames: tuple).
Allocate a new argument vector and keyword names tuple. Return the argument
vector; return NULL with exception set on error. Return the keyword names
tuple in *p_kwnames.
This also checks that all keyword names are strings. If not, a TypeError is
raised.
The newly allocated argument vector supports PY_VECTORCALL_ARGUMENTS_OFFSET.
When done, you must call _PyStack_UnpackDict_Free(stack, nargs, kwnames) */
static PyObject *const *
_PyStack_UnpackDict(PyThreadState *tstate,
PyObject *const *args, Py_ssize_t nargs,
PyObject *kwargs, PyObject **p_kwnames)
{
assert(nargs >= 0);
assert(kwargs != NULL);
assert(PyDict_Check(kwargs));
Py_ssize_t nkwargs = PyDict_GET_SIZE(kwargs);
/* Check for overflow in the PyMem_Malloc() call below. The subtraction
* in this check cannot overflow: both maxnargs and nkwargs are
* non-negative signed integers, so their difference fits in the type. */
Py_ssize_t maxnargs = PY_SSIZE_T_MAX / sizeof(args[0]) - 1;
if (nargs > maxnargs - nkwargs) {
_PyErr_NoMemory(tstate);
return NULL;
}
/* Add 1 to support PY_VECTORCALL_ARGUMENTS_OFFSET */
PyObject **stack = PyMem_Malloc((1 + nargs + nkwargs) * sizeof(args[0]));
if (stack == NULL) {
_PyErr_NoMemory(tstate);
return NULL;
}
PyObject *kwnames = PyTuple_New(nkwargs);
if (kwnames == NULL) {
PyMem_Free(stack);
return NULL;
}
stack++; /* For PY_VECTORCALL_ARGUMENTS_OFFSET */
/* Copy positional arguments */
for (Py_ssize_t i = 0; i < nargs; i++) {
Py_INCREF(args[i]);
stack[i] = args[i];
}
PyObject **kwstack = stack + nargs;
/* This loop doesn't support lookup function mutating the dictionary
to change its size. It's a deliberate choice for speed, this function is
called in the performance critical hot code. */
Py_ssize_t pos = 0, i = 0;
PyObject *key, *value;
unsigned long keys_are_strings = Py_TPFLAGS_UNICODE_SUBCLASS;
while (PyDict_Next(kwargs, &pos, &key, &value)) {
keys_are_strings &= Py_TYPE(key)->tp_flags;
Py_INCREF(key);
Py_INCREF(value);
PyTuple_SET_ITEM(kwnames, i, key);
kwstack[i] = value;
i++;
}
/* keys_are_strings has the value Py_TPFLAGS_UNICODE_SUBCLASS if that
* flag is set for all keys. Otherwise, keys_are_strings equals 0.
* We do this check once at the end instead of inside the loop above
* because it simplifies the deallocation in the failing case.
* It happens to also make the loop above slightly more efficient. */
if (!keys_are_strings) {
_PyErr_SetString(tstate, PyExc_TypeError,
"keywords must be strings");
_PyStack_UnpackDict_Free(stack, nargs, kwnames);
return NULL;
}
*p_kwnames = kwnames;
return stack;
}
static void
_PyStack_UnpackDict_Free(PyObject *const *stack, Py_ssize_t nargs,
PyObject *kwnames)
{
Py_ssize_t n = PyTuple_GET_SIZE(kwnames) + nargs;
for (Py_ssize_t i = 0; i < n; i++) {
Py_DECREF(stack[i]);
}
PyMem_Free((PyObject **)stack - 1);
Py_DECREF(kwnames);
}