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/* Generator object implementation */
#include "Python.h"
#include "frameobject.h"
#include "genobject.h"
#include "ceval.h"
#include "structmember.h"
static int
gen_traverse(PyGenObject *gen, visitproc visit, void *arg)
{
return visit((PyObject *)gen->gi_frame, arg);
}
static void
gen_dealloc(PyGenObject *gen)
{
_PyObject_GC_UNTRACK(gen);
if (gen->gi_weakreflist != NULL)
PyObject_ClearWeakRefs((PyObject *) gen);
Py_DECREF(gen->gi_frame);
PyObject_GC_Del(gen);
}
static PyObject *
gen_iternext(PyGenObject *gen)
{
PyThreadState *tstate = PyThreadState_GET();
PyFrameObject *f = gen->gi_frame;
PyObject *result;
if (gen->gi_running) {
PyErr_SetString(PyExc_ValueError,
"generator already executing");
return NULL;
}
if (f->f_stacktop == NULL)
return NULL;
/* Generators always return to their most recent caller, not
* necessarily their creator. */
Py_XINCREF(tstate->frame);
assert(f->f_back == NULL);
f->f_back = tstate->frame;
gen->gi_running = 1;
result = PyEval_EvalFrame(f);
gen->gi_running = 0;
/* Don't keep the reference to f_back any longer than necessary. It
* may keep a chain of frames alive or it could create a reference
* cycle. */
assert(f->f_back != NULL);
Py_DECREF(f->f_back);
f->f_back = NULL;
/* If the generator just returned (as opposed to yielding), signal
* that the generator is exhausted. */
if (result == Py_None && f->f_stacktop == NULL) {
Py_DECREF(result);
result = NULL;
}
return result;
}
static PyMemberDef gen_memberlist[] = {
{"gi_frame", T_OBJECT, offsetof(PyGenObject, gi_frame), RO},
{"gi_running", T_INT, offsetof(PyGenObject, gi_running), RO},
{NULL} /* Sentinel */
};
PyTypeObject PyGen_Type = {
PyObject_HEAD_INIT(&PyType_Type)
0, /* ob_size */
"generator", /* tp_name */
sizeof(PyGenObject), /* tp_basicsize */
0, /* tp_itemsize */
/* methods */
(destructor)gen_dealloc, /* tp_dealloc */
0, /* tp_print */
0, /* tp_getattr */
0, /* tp_setattr */
0, /* tp_compare */
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)gen_traverse, /* tp_traverse */
0, /* tp_clear */
0, /* tp_richcompare */
offsetof(PyGenObject, gi_weakreflist), /* tp_weaklistoffset */
PyObject_SelfIter, /* tp_iter */
(iternextfunc)gen_iternext, /* tp_iternext */
0, /* tp_methods */
gen_memberlist, /* tp_members */
0, /* tp_getset */
0, /* tp_base */
0, /* tp_dict */
};
PyObject *
PyGen_New(PyFrameObject *f)
{
PyGenObject *gen = PyObject_GC_New(PyGenObject, &PyGen_Type);
if (gen == NULL) {
Py_DECREF(f);
return NULL;
}
gen->gi_frame = f;
gen->gi_running = 0;
gen->gi_weakreflist = NULL;
_PyObject_GC_TRACK(gen);
return (PyObject *)gen;
}
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