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cpython/Objects/iterobject.c

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/* Iterator objects */
#include "Python.h"
#include "pycore_object.h"
typedef struct {
PyObject_HEAD
Py_ssize_t it_index;
PyObject *it_seq; /* Set to NULL when iterator is exhausted */
} seqiterobject;
_Py_IDENTIFIER(iter);
PyObject *
PySeqIter_New(PyObject *seq)
{
seqiterobject *it;
if (!PySequence_Check(seq)) {
PyErr_BadInternalCall();
return NULL;
}
it = PyObject_GC_New(seqiterobject, &PySeqIter_Type);
if (it == NULL)
return NULL;
it->it_index = 0;
Py_INCREF(seq);
it->it_seq = seq;
_PyObject_GC_TRACK(it);
return (PyObject *)it;
}
static void
iter_dealloc(seqiterobject *it)
{
_PyObject_GC_UNTRACK(it);
Py_XDECREF(it->it_seq);
PyObject_GC_Del(it);
}
static int
iter_traverse(seqiterobject *it, visitproc visit, void *arg)
{
Py_VISIT(it->it_seq);
return 0;
}
static PyObject *
iter_iternext(PyObject *iterator)
{
seqiterobject *it;
PyObject *seq;
PyObject *result;
assert(PySeqIter_Check(iterator));
it = (seqiterobject *)iterator;
seq = it->it_seq;
if (seq == NULL)
return NULL;
if (it->it_index == PY_SSIZE_T_MAX) {
PyErr_SetString(PyExc_OverflowError,
"iter index too large");
return NULL;
}
result = PySequence_GetItem(seq, it->it_index);
if (result != NULL) {
it->it_index++;
return result;
}
if (PyErr_ExceptionMatches(PyExc_IndexError) ||
PyErr_ExceptionMatches(PyExc_StopIteration))
{
PyErr_Clear();
it->it_seq = NULL;
Py_DECREF(seq);
}
return NULL;
}
static PyObject *
iter_len(seqiterobject *it, PyObject *Py_UNUSED(ignored))
{
Py_ssize_t seqsize, len;
if (it->it_seq) {
if (_PyObject_HasLen(it->it_seq)) {
seqsize = PySequence_Size(it->it_seq);
if (seqsize == -1)
return NULL;
}
else {
Py_RETURN_NOTIMPLEMENTED;
}
len = seqsize - it->it_index;
if (len >= 0)
return PyLong_FromSsize_t(len);
}
return PyLong_FromLong(0);
}
PyDoc_STRVAR(length_hint_doc, "Private method returning an estimate of len(list(it)).");
static PyObject *
iter_reduce(seqiterobject *it, PyObject *Py_UNUSED(ignored))
{
if (it->it_seq != NULL)
return Py_BuildValue("N(O)n", _PyEval_GetBuiltinId(&PyId_iter),
it->it_seq, it->it_index);
else
return Py_BuildValue("N(())", _PyEval_GetBuiltinId(&PyId_iter));
}
PyDoc_STRVAR(reduce_doc, "Return state information for pickling.");
static PyObject *
iter_setstate(seqiterobject *it, PyObject *state)
{
Py_ssize_t index = PyLong_AsSsize_t(state);
if (index == -1 && PyErr_Occurred())
return NULL;
if (it->it_seq != NULL) {
if (index < 0)
index = 0;
it->it_index = index;
}
Py_RETURN_NONE;
}
PyDoc_STRVAR(setstate_doc, "Set state information for unpickling.");
static PyMethodDef seqiter_methods[] = {
{"__length_hint__", (PyCFunction)iter_len, METH_NOARGS, length_hint_doc},
{"__reduce__", (PyCFunction)iter_reduce, METH_NOARGS, reduce_doc},
{"__setstate__", (PyCFunction)iter_setstate, METH_O, setstate_doc},
{NULL, NULL} /* sentinel */
};
PyTypeObject PySeqIter_Type = {
PyVarObject_HEAD_INIT(&PyType_Type, 0)
"iterator", /* tp_name */
sizeof(seqiterobject), /* tp_basicsize */
0, /* tp_itemsize */
/* methods */
(destructor)iter_dealloc, /* tp_dealloc */
0, /* tp_vectorcall_offset */
0, /* tp_getattr */
0, /* tp_setattr */
0, /* tp_as_async */
0, /* tp_repr */
0, /* tp_as_number */
0, /* tp_as_sequence */
0, /* tp_as_mapping */
0, /* tp_hash */
0, /* tp_call */
0, /* tp_str */
PyObject_GenericGetAttr, /* tp_getattro */
0, /* tp_setattro */
0, /* tp_as_buffer */
Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC, /* tp_flags */
0, /* tp_doc */
(traverseproc)iter_traverse, /* tp_traverse */
0, /* tp_clear */
0, /* tp_richcompare */
0, /* tp_weaklistoffset */
PyObject_SelfIter, /* tp_iter */
iter_iternext, /* tp_iternext */
seqiter_methods, /* tp_methods */
0, /* tp_members */
};
/* -------------------------------------- */
typedef struct {
PyObject_HEAD
PyObject *it_callable; /* Set to NULL when iterator is exhausted */
PyObject *it_sentinel; /* Set to NULL when iterator is exhausted */
} calliterobject;
PyObject *
PyCallIter_New(PyObject *callable, PyObject *sentinel)
{
calliterobject *it;
it = PyObject_GC_New(calliterobject, &PyCallIter_Type);
if (it == NULL)
return NULL;
Py_INCREF(callable);
it->it_callable = callable;
Py_INCREF(sentinel);
it->it_sentinel = sentinel;
_PyObject_GC_TRACK(it);
return (PyObject *)it;
}
static void
calliter_dealloc(calliterobject *it)
{
_PyObject_GC_UNTRACK(it);
Py_XDECREF(it->it_callable);
Py_XDECREF(it->it_sentinel);
PyObject_GC_Del(it);
}
static int
calliter_traverse(calliterobject *it, visitproc visit, void *arg)
{
Py_VISIT(it->it_callable);
Py_VISIT(it->it_sentinel);
return 0;
}
static PyObject *
calliter_iternext(calliterobject *it)
{
PyObject *result;
if (it->it_callable == NULL) {
return NULL;
}
result = _PyObject_CallNoArg(it->it_callable);
if (result != NULL) {
int ok;
ok = PyObject_RichCompareBool(it->it_sentinel, result, Py_EQ);
if (ok == 0) {
return result; /* Common case, fast path */
}
Py_DECREF(result);
if (ok > 0) {
Py_CLEAR(it->it_callable);
Py_CLEAR(it->it_sentinel);
}
}
else if (PyErr_ExceptionMatches(PyExc_StopIteration)) {
PyErr_Clear();
Py_CLEAR(it->it_callable);
Py_CLEAR(it->it_sentinel);
}
return NULL;
}
static PyObject *
calliter_reduce(calliterobject *it, PyObject *Py_UNUSED(ignored))
{
if (it->it_callable != NULL && it->it_sentinel != NULL)
return Py_BuildValue("N(OO)", _PyEval_GetBuiltinId(&PyId_iter),
it->it_callable, it->it_sentinel);
else
return Py_BuildValue("N(())", _PyEval_GetBuiltinId(&PyId_iter));
}
static PyMethodDef calliter_methods[] = {
{"__reduce__", (PyCFunction)calliter_reduce, METH_NOARGS, reduce_doc},
{NULL, NULL} /* sentinel */
};
PyTypeObject PyCallIter_Type = {
PyVarObject_HEAD_INIT(&PyType_Type, 0)
"callable_iterator", /* tp_name */
sizeof(calliterobject), /* tp_basicsize */
0, /* tp_itemsize */
/* methods */
(destructor)calliter_dealloc, /* tp_dealloc */
0, /* tp_vectorcall_offset */
0, /* tp_getattr */
0, /* tp_setattr */
0, /* tp_as_async */
0, /* tp_repr */
0, /* tp_as_number */
0, /* tp_as_sequence */
0, /* tp_as_mapping */
0, /* tp_hash */
0, /* tp_call */
0, /* tp_str */
PyObject_GenericGetAttr, /* tp_getattro */
0, /* tp_setattro */
0, /* tp_as_buffer */
Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC, /* tp_flags */
0, /* tp_doc */
(traverseproc)calliter_traverse, /* tp_traverse */
0, /* tp_clear */
0, /* tp_richcompare */
0, /* tp_weaklistoffset */
PyObject_SelfIter, /* tp_iter */
(iternextfunc)calliter_iternext, /* tp_iternext */
calliter_methods, /* tp_methods */
};
/* -------------------------------------- */
typedef struct {
PyObject_HEAD
PyObject *wrapped;
PyObject *default_value;
} anextawaitableobject;
static void
anextawaitable_dealloc(anextawaitableobject *obj)
{
_PyObject_GC_UNTRACK(obj);
Py_XDECREF(obj->wrapped);
Py_XDECREF(obj->default_value);
PyObject_GC_Del(obj);
}
static int
anextawaitable_traverse(anextawaitableobject *obj, visitproc visit, void *arg)
{
Py_VISIT(obj->wrapped);
Py_VISIT(obj->default_value);
return 0;
}
static PyObject *
anextawaitable_iternext(anextawaitableobject *obj)
{
/* Consider the following class:
*
* class A:
* async def __anext__(self):
* ...
* a = A()
*
* Then `await anext(a)` should call
* a.__anext__().__await__().__next__()
*
* On the other hand, given
*
* async def agen():
* yield 1
* yield 2
* gen = agen()
*
* Then `await anext(gen)` can just call
* gen.__anext__().__next__()
*/
assert(obj->wrapped != NULL);
PyObject *awaitable = _PyCoro_GetAwaitableIter(obj->wrapped);
if (awaitable == NULL) {
return NULL;
}
if (Py_TYPE(awaitable)->tp_iternext == NULL) {
/* _PyCoro_GetAwaitableIter returns a Coroutine, a Generator,
* or an iterator. Of these, only coroutines lack tp_iternext.
*/
assert(PyCoro_CheckExact(awaitable));
unaryfunc getter = Py_TYPE(awaitable)->tp_as_async->am_await;
PyObject *new_awaitable = getter(awaitable);
if (new_awaitable == NULL) {
Py_DECREF(awaitable);
return NULL;
}
Py_SETREF(awaitable, new_awaitable);
if (Py_TYPE(awaitable)->tp_iternext == NULL) {
PyErr_SetString(PyExc_TypeError,
"__await__ returned a non-iterable");
Py_DECREF(awaitable);
return NULL;
}
}
PyObject *result = (*Py_TYPE(awaitable)->tp_iternext)(awaitable);
Py_DECREF(awaitable);
if (result != NULL) {
return result;
}
if (PyErr_ExceptionMatches(PyExc_StopAsyncIteration)) {
_PyGen_SetStopIterationValue(obj->default_value);
}
return NULL;
}
static PyAsyncMethods anextawaitable_as_async = {
PyObject_SelfIter, /* am_await */
0, /* am_aiter */
0, /* am_anext */
0, /* am_send */
};
PyTypeObject _PyAnextAwaitable_Type = {
PyVarObject_HEAD_INIT(&PyType_Type, 0)
"anext_awaitable", /* tp_name */
sizeof(anextawaitableobject), /* tp_basicsize */
0, /* tp_itemsize */
/* methods */
(destructor)anextawaitable_dealloc, /* tp_dealloc */
0, /* tp_vectorcall_offset */
0, /* tp_getattr */
0, /* tp_setattr */
&anextawaitable_as_async, /* tp_as_async */
0, /* tp_repr */
0, /* tp_as_number */
0, /* tp_as_sequence */
0, /* tp_as_mapping */
0, /* tp_hash */
0, /* tp_call */
0, /* tp_str */
PyObject_GenericGetAttr, /* tp_getattro */
0, /* tp_setattro */
0, /* tp_as_buffer */
Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC, /* tp_flags */
0, /* tp_doc */
(traverseproc)anextawaitable_traverse, /* tp_traverse */
0, /* tp_clear */
0, /* tp_richcompare */
0, /* tp_weaklistoffset */
PyObject_SelfIter, /* tp_iter */
(unaryfunc)anextawaitable_iternext, /* tp_iternext */
0, /* tp_methods */
};
PyObject *
PyAnextAwaitable_New(PyObject *awaitable, PyObject *default_value)
{
anextawaitableobject *anext = PyObject_GC_New(
anextawaitableobject, &_PyAnextAwaitable_Type);
if (anext == NULL) {
return NULL;
}
Py_INCREF(awaitable);
anext->wrapped = awaitable;
Py_INCREF(default_value);
anext->default_value = default_value;
_PyObject_GC_TRACK(anext);
return (PyObject *)anext;
}
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