cpython/Objects/iterobject.c at doc-link-https · 180909/cpython · GitHub

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/* Iterator objects */

#include "Python.h"

#include "pycore_call.h" // _PyObject_CallNoArgs()

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

typedef struct {

PyObject_HEAD

Py_ssize_t it_index;

PyObject *it_seq; /* Set to NULL when iterator is exhausted */

} seqiterobject;

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_GetBuiltin(&_Py_ID(iter)),

it->it_seq, it->it_index);

else

return Py_BuildValue("N(())", _PyEval_GetBuiltin(&_Py_ID(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_CallNoArgs(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_GetBuiltin(&_Py_ID(iter)),

it->it_callable, it->it_sentinel);

else

return Py_BuildValue("N(())", _PyEval_GetBuiltin(&_Py_ID(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_getiter(anextawaitableobject *obj)

{

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 (!PyIter_Check(awaitable)) {

PyErr_SetString(PyExc_TypeError,

"__await__ returned a non-iterable");

Py_DECREF(awaitable);

return NULL;

}

return awaitable;

}

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__()

PyObject *awaitable = anextawaitable_getiter(obj);

if (awaitable == NULL) {

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 PyObject *

anextawaitable_proxy(anextawaitableobject *obj, char *meth, PyObject *arg) {

PyObject *awaitable = anextawaitable_getiter(obj);

if (awaitable == NULL) {

return NULL;

}

PyObject *ret = PyObject_CallMethod(awaitable, meth, "O", arg);

Py_DECREF(awaitable);

if (ret != NULL) {

return ret;

}

if (PyErr_ExceptionMatches(PyExc_StopAsyncIteration)) {

/* `anextawaitableobject` is only used by `anext()` when

* a default value is provided. So when we have a StopAsyncIteration

* exception we replace it with a `StopIteration(default)`, as if

* it was the return value of `__anext__()` coroutine.

_PyGen_SetStopIterationValue(obj->default_value);

}

return NULL;

}

static PyObject *

anextawaitable_send(anextawaitableobject *obj, PyObject *arg) {

return anextawaitable_proxy(obj, "send", arg);

}

static PyObject *

anextawaitable_throw(anextawaitableobject *obj, PyObject *arg) {

return anextawaitable_proxy(obj, "throw", arg);

}

static PyObject *

anextawaitable_close(anextawaitableobject *obj, PyObject *arg) {

return anextawaitable_proxy(obj, "close", arg);

}

PyDoc_STRVAR(send_doc,

"send(arg) -> send 'arg' into the wrapped iterator,\n\

return next yielded value or raise StopIteration.");

PyDoc_STRVAR(throw_doc,

"throw(value)\n\

throw(typ[,val[,tb]])\n\

\n\

raise exception in the wrapped iterator, return next yielded value\n\

or raise StopIteration.\n\

the (type, val, tb) signature is deprecated, \n\

and may be removed in a future version of Python.");

PyDoc_STRVAR(close_doc,

"close() -> raise GeneratorExit inside generator.");

static PyMethodDef anextawaitable_methods[] = {

{"send",(PyCFunction)anextawaitable_send, METH_O, send_doc},

{"throw",(PyCFunction)anextawaitable_throw, METH_VARARGS, throw_doc},

{"close",(PyCFunction)anextawaitable_close, METH_VARARGS, close_doc},

{NULL, NULL} /* Sentinel */

};

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 */

anextawaitable_methods, /* 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;

}

cpython/Objects/iterobject.c at doc-link-https · 180909/cpython · GitHub

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