/* Generator object implementation */

#include "Python.h"

#include "internal/pystate.h"

#include "frameobject.h"

#include "structmember.h"

#include "opcode.h"

static PyObject *gen_close(PyGenObject *, PyObject *);

static PyObject *async_gen_asend_new(PyAsyncGenObject *, PyObject *);

static PyObject *async_gen_athrow_new(PyAsyncGenObject *, PyObject *);

static char *NON_INIT_CORO_MSG = "can't send non-None value to a "

"just-started coroutine";

static char *ASYNC_GEN_IGNORED_EXIT_MSG =

"async generator ignored GeneratorExit";

static int

gen_traverse(PyGenObject *gen, visitproc visit, void *arg)

{

Py_VISIT((PyObject *)gen->gi_frame);

Py_VISIT(gen->gi_code);

Py_VISIT(gen->gi_name);

Py_VISIT(gen->gi_qualname);

return 0;

}

void

_PyGen_Finalize(PyObject *self)

{

PyGenObject *gen = (PyGenObject *)self;

PyObject *res = NULL;

PyObject *error_type, *error_value, *error_traceback;

if (gen->gi_frame == NULL || gen->gi_frame->f_stacktop == NULL)

/* Generator isn't paused, so no need to close */

return;

if (PyAsyncGen_CheckExact(self)) {

PyAsyncGenObject *agen = (PyAsyncGenObject*)self;

PyObject *finalizer = agen->ag_finalizer;

if (finalizer && !agen->ag_closed) {

/* Save the current exception, if any. */

PyErr_Fetch(&error_type, &error_value, &error_traceback);

res = PyObject_CallFunctionObjArgs(finalizer, self, NULL);

if (res == NULL) {

PyErr_WriteUnraisable(self);

} else {

Py_DECREF(res);

}

/* Restore the saved exception. */

PyErr_Restore(error_type, error_value, error_traceback);

return;

}

}

/* Save the current exception, if any. */

PyErr_Fetch(&error_type, &error_value, &error_traceback);

/* If `gen` is a coroutine, and if it was never awaited on,

issue a RuntimeWarning. */

if (gen->gi_code != NULL &&

((PyCodeObject *)gen->gi_code)->co_flags & CO_COROUTINE &&

gen->gi_frame->f_lasti == -1) {

if (!error_value) {

PyErr_WarnFormat(PyExc_RuntimeWarning, 1,

"coroutine '%.50S' was never awaited",

gen->gi_qualname);

}

}

else {

res = gen_close(gen, NULL);

}

if (res == NULL) {

if (PyErr_Occurred())

PyErr_WriteUnraisable(self);

}

else {

Py_DECREF(res);

}

/* Restore the saved exception. */

PyErr_Restore(error_type, error_value, error_traceback);

}

static void

gen_dealloc(PyGenObject *gen)

{

PyObject *self = (PyObject *) gen;

_PyObject_GC_UNTRACK(gen);

if (gen->gi_weakreflist != NULL)

PyObject_ClearWeakRefs(self);

_PyObject_GC_TRACK(self);

if (PyObject_CallFinalizerFromDealloc(self))

return; /* resurrected. :( */

_PyObject_GC_UNTRACK(self);

if (PyAsyncGen_CheckExact(gen)) {

/* We have to handle this case for asynchronous generators

right here, because this code has to be between UNTRACK

and GC_Del. */

Py_CLEAR(((PyAsyncGenObject*)gen)->ag_finalizer);

}

if (gen->gi_frame != NULL) {

gen->gi_frame->f_gen = NULL;

Py_CLEAR(gen->gi_frame);

}

Py_CLEAR(gen->gi_code);

Py_CLEAR(gen->gi_name);

Py_CLEAR(gen->gi_qualname);

PyObject_GC_Del(gen);

}

static PyObject *

gen_send_ex(PyGenObject *gen, PyObject *arg, int exc, int closing)

{

PyThreadState *tstate = PyThreadState_GET();

PyFrameObject *f = gen->gi_frame;

PyObject *result;

if (gen->gi_running) {

char *msg = "generator already executing";

if (PyCoro_CheckExact(gen)) {

msg = "coroutine already executing";

}

else if (PyAsyncGen_CheckExact(gen)) {

msg = "async generator already executing";

}

PyErr_SetString(PyExc_ValueError, msg);

return NULL;

}

if (f == NULL || f->f_stacktop == NULL) {

if (PyCoro_CheckExact(gen) && !closing) {

/* `gen` is an exhausted coroutine: raise an error,

except when called from gen_close(), which should

always be a silent method. */

PyErr_SetString(

PyExc_RuntimeError,

"cannot reuse already awaited coroutine");

}

else if (arg && !exc) {

/* `gen` is an exhausted generator:

only set exception if called from send(). */

if (PyAsyncGen_CheckExact(gen)) {

PyErr_SetNone(PyExc_StopAsyncIteration);

}

else {

PyErr_SetNone(PyExc_StopIteration);

}

}

return NULL;

}

if (f->f_lasti == -1) {

if (arg && arg != Py_None) {

char *msg = "can't send non-None value to a "

"just-started generator";

if (PyCoro_CheckExact(gen)) {

msg = NON_INIT_CORO_MSG;

}

else if (PyAsyncGen_CheckExact(gen)) {

msg = "can't send non-None value to a "

"just-started async generator";

}

PyErr_SetString(PyExc_TypeError, msg);

return NULL;

}

} else {

/* Push arg onto the frame's value stack */

result = arg ? arg : Py_None;

Py_INCREF(result);

*(f->f_stacktop++) = result;

}

/* 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_EvalFrameEx(f, exc);

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 == tstate->frame);

Py_CLEAR(f->f_back);

/* If the generator just returned (as opposed to yielding), signal

* that the generator is exhausted. */

if (result && f->f_stacktop == NULL) {

if (result == Py_None) {

/* Delay exception instantiation if we can */

if (PyAsyncGen_CheckExact(gen)) {

PyErr_SetNone(PyExc_StopAsyncIteration);

}

else {

PyErr_SetNone(PyExc_StopIteration);

}

}

else {

/* Async generators cannot return anything but None */

assert(!PyAsyncGen_CheckExact(gen));

_PyGen_SetStopIterationValue(result);

}

Py_CLEAR(result);

}

else if (!result && PyErr_ExceptionMatches(PyExc_StopIteration)) {

/* Check for __future__ generator_stop and conditionally turn

* a leaking StopIteration into RuntimeError (with its cause

* set appropriately). */

const int check_stop_iter_error_flags = CO_FUTURE_GENERATOR_STOP |

CO_COROUTINE |

CO_ITERABLE_COROUTINE |

CO_ASYNC_GENERATOR;

if (gen->gi_code != NULL &&

((PyCodeObject *)gen->gi_code)->co_flags &

check_stop_iter_error_flags)

{

/* `gen` is either:

* a generator with CO_FUTURE_GENERATOR_STOP flag;

* a coroutine;

* a generator with CO_ITERABLE_COROUTINE flag

(decorated with types.coroutine decorator);

* an async generator.

*/

const char *msg = "generator raised StopIteration";

if (PyCoro_CheckExact(gen)) {

msg = "coroutine raised StopIteration";

}

else if PyAsyncGen_CheckExact(gen) {

msg = "async generator raised StopIteration";

}

_PyErr_FormatFromCause(PyExc_RuntimeError, "%s", msg);

}

else {

/* `gen` is an ordinary generator without

CO_FUTURE_GENERATOR_STOP flag.

*/

PyObject *exc, *val, *tb;

/* Pop the exception before issuing a warning. */

PyErr_Fetch(&exc, &val, &tb);

if (PyErr_WarnFormat(PyExc_DeprecationWarning, 1,

"generator '%.50S' raised StopIteration",

gen->gi_qualname)) {

/* Warning was converted to an error. */

Py_XDECREF(exc);

Py_XDECREF(val);

Py_XDECREF(tb);

}

else {

PyErr_Restore(exc, val, tb);

}

}

}

else if (PyAsyncGen_CheckExact(gen) && !result &&

PyErr_ExceptionMatches(PyExc_StopAsyncIteration))

{

/* code in `gen` raised a StopAsyncIteration error:

raise a RuntimeError.

*/

const char *msg = "async generator raised StopAsyncIteration";

_PyErr_FormatFromCause(PyExc_RuntimeError, "%s", msg);

}

if (!result || f->f_stacktop == NULL) {

/* generator can't be rerun, so release the frame */

/* first clean reference cycle through stored exception traceback */

PyObject *t, *v, *tb;

t = f->f_exc_type;

v = f->f_exc_value;

tb = f->f_exc_traceback;

f->f_exc_type = NULL;

f->f_exc_value = NULL;

f->f_exc_traceback = NULL;

Py_XDECREF(t);

Py_XDECREF(v);

Py_XDECREF(tb);

gen->gi_frame->f_gen = NULL;

gen->gi_frame = NULL;

Py_DECREF(f);

}

return result;

}

PyDoc_STRVAR(send_doc,

"send(arg) -> send 'arg' into generator,\n\

return next yielded value or raise StopIteration.");

PyObject *

_PyGen_Send(PyGenObject *gen, PyObject *arg)

{

return gen_send_ex(gen, arg, 0, 0);

}

PyDoc_STRVAR(close_doc,

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

/*

* This helper function is used by gen_close and gen_throw to

* close a subiterator being delegated to by yield-from.

*/

static int

gen_close_iter(PyObject *yf)

{

PyObject *retval = NULL;

_Py_IDENTIFIER(close);

if (PyGen_CheckExact(yf) || PyCoro_CheckExact(yf)) {

retval = gen_close((PyGenObject *)yf, NULL);

if (retval == NULL)

return -1;

}

else {

PyObject *meth = _PyObject_GetAttrId(yf, &PyId_close);

if (meth == NULL) {

if (!PyErr_ExceptionMatches(PyExc_AttributeError))

PyErr_WriteUnraisable(yf);

PyErr_Clear();

}

else {

retval = _PyObject_CallNoArg(meth);

Py_DECREF(meth);

if (retval == NULL)

return -1;

}

}

Py_XDECREF(retval);

return 0;

}

PyObject *

_PyGen_yf(PyGenObject *gen)

{

PyObject *yf = NULL;

PyFrameObject *f = gen->gi_frame;

if (f && f->f_stacktop) {

PyObject *bytecode = f->f_code->co_code;

unsigned char *code = (unsigned char *)PyBytes_AS_STRING(bytecode);

if (f->f_lasti < 0) {

/* Return immediately if the frame didn't start yet. YIELD_FROM

always come after LOAD_CONST: a code object should not start

with YIELD_FROM */

assert(code[0] != YIELD_FROM);

return NULL;

}

if (code[f->f_lasti + sizeof(_Py_CODEUNIT)] != YIELD_FROM)

return NULL;

yf = f->f_stacktop[-1];

Py_INCREF(yf);

}

return yf;

}

static PyObject *

gen_close(PyGenObject *gen, PyObject *args)

{

PyObject *retval;

PyObject *yf = _PyGen_yf(gen);

int err = 0;

if (yf) {

gen->gi_running = 1;

err = gen_close_iter(yf);

gen->gi_running = 0;

Py_DECREF(yf);

}

if (err == 0)

PyErr_SetNone(PyExc_GeneratorExit);

retval = gen_send_ex(gen, Py_None, 1, 1);

if (retval) {

char *msg = "generator ignored GeneratorExit";

if (PyCoro_CheckExact(gen)) {

msg = "coroutine ignored GeneratorExit";

} else if (PyAsyncGen_CheckExact(gen)) {

msg = ASYNC_GEN_IGNORED_EXIT_MSG;

}

Py_DECREF(retval);

PyErr_SetString(PyExc_RuntimeError, msg);

return NULL;

}

if (PyErr_ExceptionMatches(PyExc_StopIteration)

|| PyErr_ExceptionMatches(PyExc_GeneratorExit)) {

PyErr_Clear(); /* ignore these errors */

Py_RETURN_NONE;

}

return NULL;

}

PyDoc_STRVAR(throw_doc,

"throw(typ[,val[,tb]]) -> raise exception in generator,\n\

return next yielded value or raise StopIteration.");

static PyObject *

_gen_throw(PyGenObject *gen, int close_on_genexit,

PyObject *typ, PyObject *val, PyObject *tb)

{

PyObject *yf = _PyGen_yf(gen);

_Py_IDENTIFIER(throw);

if (yf) {

PyObject *ret;

int err;

if (PyErr_GivenExceptionMatches(typ, PyExc_GeneratorExit) &&

close_on_genexit

) {

/* Asynchronous generators *should not* be closed right away.

We have to allow some awaits to work it through, hence the

`close_on_genexit` parameter here.

*/

gen->gi_running = 1;

err = gen_close_iter(yf);

gen->gi_running = 0;

Py_DECREF(yf);

if (err < 0)

return gen_send_ex(gen, Py_None, 1, 0);

goto throw_here;

}

if (PyGen_CheckExact(yf) || PyCoro_CheckExact(yf)) {

/* `yf` is a generator or a coroutine. */

gen->gi_running = 1;

/* Close the generator that we are currently iterating with

'yield from' or awaiting on with 'await'. */

ret = _gen_throw((PyGenObject *)yf, close_on_genexit,

typ, val, tb);

gen->gi_running = 0;

} else {

/* `yf` is an iterator or a coroutine-like object. */

PyObject *meth = _PyObject_GetAttrId(yf, &PyId_throw);

if (meth == NULL) {

if (!PyErr_ExceptionMatches(PyExc_AttributeError)) {

Py_DECREF(yf);

return NULL;

}

PyErr_Clear();

Py_DECREF(yf);

goto throw_here;

}

gen->gi_running = 1;

ret = PyObject_CallFunctionObjArgs(meth, typ, val, tb, NULL);

gen->gi_running = 0;

Py_DECREF(meth);

}

Py_DECREF(yf);

if (!ret) {

PyObject *val;

/* Pop subiterator from stack */

ret = *(--gen->gi_frame->f_stacktop);

assert(ret == yf);

Py_DECREF(ret);

/* Termination repetition of YIELD_FROM */

assert(gen->gi_frame->f_lasti >= 0);

gen->gi_frame->f_lasti += sizeof(_Py_CODEUNIT);

if (_PyGen_FetchStopIterationValue(&val) == 0) {

ret = gen_send_ex(gen, val, 0, 0);

Py_DECREF(val);

} else {

ret = gen_send_ex(gen, Py_None, 1, 0);

}

}

return ret;

}

throw_here:

/* First, check the traceback argument, replacing None with

NULL. */

if (tb == Py_None) {

tb = NULL;

}

else if (tb != NULL && !PyTraceBack_Check(tb)) {

PyErr_SetString(PyExc_TypeError,

"throw() third argument must be a traceback object");

return NULL;

}

Py_INCREF(typ);

Py_XINCREF(val);

Py_XINCREF(tb);

if (PyExceptionClass_Check(typ))

PyErr_NormalizeException(&typ, &val, &tb);

else if (PyExceptionInstance_Check(typ)) {

/* Raising an instance. The value should be a dummy. */

if (val && val != Py_None) {

PyErr_SetString(PyExc_TypeError,

"instance exception may not have a separate value");

goto failed_throw;

}

else {

/* Normalize to raise <class>, <instance> */

Py_XDECREF(val);

val = typ;

typ = PyExceptionInstance_Class(typ);

Py_INCREF(typ);

if (tb == NULL)

/* Returns NULL if there's no traceback */

tb = PyException_GetTraceback(val);

}

}

else {

/* Not something you can raise. throw() fails. */

PyErr_Format(PyExc_TypeError,

"exceptions must be classes or instances "

"deriving from BaseException, not %s",

Py_TYPE(typ)->tp_name);

goto failed_throw;

}

PyErr_Restore(typ, val, tb);

return gen_send_ex(gen, Py_None, 1, 0);

failed_throw:

/* Didn't use our arguments, so restore their original refcounts */

Py_DECREF(typ);

Py_XDECREF(val);

Py_XDECREF(tb);

return NULL;

}

static PyObject *

gen_throw(PyGenObject *gen, PyObject *args)

{

PyObject *typ;

PyObject *tb = NULL;

PyObject *val = NULL;

if (!PyArg_UnpackTuple(args, "throw", 1, 3, &typ, &val, &tb)) {

return NULL;

}

return _gen_throw(gen, 1, typ, val, tb);

}

static PyObject *

gen_iternext(PyGenObject *gen)

{

return gen_send_ex(gen, NULL, 0, 0);

}

/*

* Set StopIteration with specified value. Value can be arbitrary object

* or NULL.

*

* Returns 0 if StopIteration is set and -1 if any other exception is set.

*/

int

_PyGen_SetStopIterationValue(PyObject *value)

{

PyObject *e;

if (value == NULL ||

(!PyTuple_Check(value) && !PyExceptionInstance_Check(value)))

{

/* Delay exception instantiation if we can */

PyErr_SetObject(PyExc_StopIteration, value);

return 0;

}

/* Construct an exception instance manually with

* PyObject_CallFunctionObjArgs and pass it to PyErr_SetObject.

*

* We do this to handle a situation when "value" is a tuple, in which

* case PyErr_SetObject would set the value of StopIteration to

* the first element of the tuple.

*

* (See PyErr_SetObject/_PyErr_CreateException code for details.)

*/

e = PyObject_CallFunctionObjArgs(PyExc_StopIteration, value, NULL);

if (e == NULL) {

return -1;

}

PyErr_SetObject(PyExc_StopIteration, e);

Py_DECREF(e);

return 0;

}

/*

* If StopIteration exception is set, fetches its 'value'

* attribute if any, otherwise sets pvalue to None.

*

* Returns 0 if no exception or StopIteration is set.

* If any other exception is set, returns -1 and leaves

* pvalue unchanged.

*/

int

_PyGen_FetchStopIterationValue(PyObject **pvalue)

{

PyObject *et, *ev, *tb;

PyObject *value = NULL;

if (PyErr_ExceptionMatches(PyExc_StopIteration)) {

PyErr_Fetch(&et, &ev, &tb);

if (ev) {

/* exception will usually be normalised already */

if (PyObject_TypeCheck(ev, (PyTypeObject *) et)) {

value = ((PyStopIterationObject *)ev)->value;

Py_INCREF(value);

Py_DECREF(ev);

} else if (et == PyExc_StopIteration && !PyTuple_Check(ev)) {

/* Avoid normalisation and take ev as value.

*

* Normalization is required if the value is a tuple, in

* that case the value of StopIteration would be set to

* the first element of the tuple.

*

* (See _PyErr_CreateException code for details.)

*/

value = ev;

} else {

/* normalisation required */

PyErr_NormalizeException(&et, &ev, &tb);

if (!PyObject_TypeCheck(ev, (PyTypeObject *)PyExc_StopIteration)) {

PyErr_Restore(et, ev, tb);

return -1;

}

value = ((PyStopIterationObject *)ev)->value;

Py_INCREF(value);

Py_DECREF(ev);

}

}

Py_XDECREF(et);

Py_XDECREF(tb);

} else if (PyErr_Occurred()) {

return -1;

}

if (value == NULL) {

value = Py_None;

Py_INCREF(value);

}

*pvalue = value;

return 0;

}

static PyObject *

gen_repr(PyGenObject *gen)

{

return PyUnicode_FromFormat("<generator object %S at %p>",

gen->gi_qualname, gen);

}

static PyObject *

gen_get_name(PyGenObject *op)

{

Py_INCREF(op->gi_name);

return op->gi_name;

}

static int

gen_set_name(PyGenObject *op, PyObject *value)

{

/* Not legal to del gen.gi_name or to set it to anything

* other than a string object. */

if (value == NULL || !PyUnicode_Check(value)) {

PyErr_SetString(PyExc_TypeError,

"__name__ must be set to a string object");

return -1;

}

Py_INCREF(value);

Py_XSETREF(op->gi_name, value);

return 0;

}

static PyObject *

gen_get_qualname(PyGenObject *op)

{

Py_INCREF(op->gi_qualname);

return op->gi_qualname;

}

static int

gen_set_qualname(PyGenObject *op, PyObject *value)

{

/* Not legal to del gen.__qualname__ or to set it to anything

* other than a string object. */

if (value == NULL || !PyUnicode_Check(value)) {

PyErr_SetString(PyExc_TypeError,

"__qualname__ must be set to a string object");

return -1;

}

Py_INCREF(value);

Py_XSETREF(op->gi_qualname, value);

return 0;

}

static PyObject *

gen_getyieldfrom(PyGenObject *gen)

{

PyObject *yf = _PyGen_yf(gen);

if (yf == NULL)

Py_RETURN_NONE;

return yf;

}

static PyGetSetDef gen_getsetlist[] = {

{"__name__", (getter)gen_get_name, (setter)gen_set_name,

PyDoc_STR("name of the generator")},

{"__qualname__", (getter)gen_get_qualname, (setter)gen_set_qualname,

PyDoc_STR("qualified name of the generator")},

{"gi_yieldfrom", (getter)gen_getyieldfrom, NULL,

PyDoc_STR("object being iterated by yield from, or None")},

{NULL} /* Sentinel */

};

static PyMemberDef gen_memberlist[] = {

{"gi_frame", T_OBJECT, offsetof(PyGenObject, gi_frame), READONLY},

{"gi_running", T_BOOL, offsetof(PyGenObject, gi_running), READONLY},

{"gi_code", T_OBJECT, offsetof(PyGenObject, gi_code), READONLY},

{NULL} /* Sentinel */

};

static PyMethodDef gen_methods[] = {

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

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

{"close",(PyCFunction)gen_close, METH_NOARGS, close_doc},

{NULL, NULL} /* Sentinel */

};

PyTypeObject PyGen_Type = {

PyVarObject_HEAD_INIT(&PyType_Type, 0)

"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_as_async */

(reprfunc)gen_repr, /* 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 |

Py_TPFLAGS_HAVE_FINALIZE, /* 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 */

gen_methods, /* tp_methods */

gen_memberlist, /* tp_members */

gen_getsetlist, /* tp_getset */

0, /* tp_base */

0, /* tp_dict */

0, /* tp_descr_get */

0, /* tp_descr_set */

0, /* tp_dictoffset */

0, /* tp_init */

0, /* tp_alloc */

0, /* tp_new */

0, /* tp_free */

0, /* tp_is_gc */

0, /* tp_bases */

0, /* tp_mro */

0, /* tp_cache */

0, /* tp_subclasses */

0, /* tp_weaklist */

0, /* tp_del */

0, /* tp_version_tag */

_PyGen_Finalize, /* tp_finalize */

};

static PyObject *

gen_new_with_qualname(PyTypeObject *type, PyFrameObject *f,

PyObject *name, PyObject *qualname)

{

PyGenObject *gen = PyObject_GC_New(PyGenObject, type);

if (gen == NULL) {

Py_DECREF(f);

return NULL;

}

gen->gi_frame = f;

f->f_gen = (PyObject *) gen;

Py_INCREF(f->f_code);

gen->gi_code = (PyObject *)(f->f_code);

gen->gi_running = 0;

gen->gi_weakreflist = NULL;

if (name != NULL)

gen->gi_name = name;

else

gen->gi_name = ((PyCodeObject *)gen->gi_code)->co_name;

Py_INCREF(gen->gi_name);

if (qualname != NULL)

gen->gi_qualname = qualname;

else

gen->gi_qualname = gen->gi_name;

Py_INCREF(gen->gi_qualname);

_PyObject_GC_TRACK(gen);

return (PyObject *)gen;

}

PyObject *

PyGen_NewWithQualName(PyFrameObject *f, PyObject *name, PyObject *qualname)

{

return gen_new_with_qualname(&PyGen_Type, f, name, qualname);

}

PyObject *

PyGen_New(PyFrameObject *f)

{

return gen_new_with_qualname(&PyGen_Type, f, NULL, NULL);

}

int

PyGen_NeedsFinalizing(PyGenObject *gen)

{

int i;

PyFrameObject *f = gen->gi_frame;

if (f == NULL || f->f_stacktop == NULL)

return 0; /* no frame or empty blockstack == no finalization */

/* Any block type besides a loop requires cleanup. */

for (i = 0; i < f->f_iblock; i++)

if (f->f_blockstack[i].b_type != SETUP_LOOP)

return 1;

/* No blocks except loops, it's safe to skip finalization. */

return 0;

}

/* Coroutine Object */

typedef struct {

PyObject_HEAD

PyCoroObject *cw_coroutine;

} PyCoroWrapper;

static int

gen_is_coroutine(PyObject *o)

{

if (PyGen_CheckExact(o)) {

PyCodeObject *code = (PyCodeObject *)((PyGenObject*)o)->gi_code;

if (code->co_flags & CO_ITERABLE_COROUTINE) {

return 1;

}

}

return 0;

}

/*

* This helper function returns an awaitable for `o`:

* - `o` if `o` is a coroutine-object;

* - `type(o)->tp_as_async->am_await(o)`

*

* Raises a TypeError if it's not possible to return

* an awaitable and returns NULL.

*/

PyObject *

_PyCoro_GetAwaitableIter(PyObject *o)

{

unaryfunc getter = NULL;

PyTypeObject *ot;

if (PyCoro_CheckExact(o) || gen_is_coroutine(o)) {

/* 'o' is a coroutine. */

Py_INCREF(o);

return o;

}

ot = Py_TYPE(o);

if (ot->tp_as_async != NULL) {

getter = ot->tp_as_async->am_await;

}

if (getter != NULL) {

PyObject *res = (*getter)(o);

if (res != NULL) {

if (PyCoro_CheckExact(res) || gen_is_coroutine(res)) {

/* __await__ must return an *iterator*, not

a coroutine or another awaitable (see PEP 492) */

PyErr_SetString(PyExc_TypeError,

"__await__() returned a coroutine");

Py_CLEAR(res);

} else if (!PyIter_Check(res)) {

PyErr_Format(PyExc_TypeError,

"__await__() returned non-iterator "

"of type '%.100s'",

Py_TYPE(res)->tp_name);

Py_CLEAR(res);

}

}

return res;

}

PyErr_Format(PyExc_TypeError,

"object %.100s can't be used in 'await' expression",

ot->tp_name);

return NULL;

}

static PyObject *

coro_repr(PyCoroObject *coro)

{

return PyUnicode_FromFormat("<coroutine object %S at %p>",

coro->cr_qualname, coro);

}

static PyObject *

coro_await(PyCoroObject *coro)

{

PyCoroWrapper *cw = PyObject_GC_New(PyCoroWrapper, &_PyCoroWrapper_Type);

if (cw == NULL) {

return NULL;

}

Py_INCREF(coro);

cw->cw_coroutine = coro;

_PyObject_GC_TRACK(cw);

return (PyObject *)cw;

}

static PyObject *

coro_get_cr_await(PyCoroObject *coro)

{

PyObject *yf = _PyGen_yf((PyGenObject *) coro);

if (yf == NULL)

Py_RETURN_NONE;

return yf;

}

static PyGetSetDef coro_getsetlist[] = {

{"__name__", (getter)gen_get_name, (setter)gen_set_name,

PyDoc_STR("name of the coroutine")},

{"__qualname__", (getter)gen_get_qualname, (setter)gen_set_qualname,

PyDoc_STR("qualified name of the coroutine")},

{"cr_await", (getter)coro_get_cr_await, NULL,

PyDoc_STR("object being awaited on, or None")},

{NULL} /* Sentinel */

};

static PyMemberDef coro_memberlist[] = {

{"cr_frame", T_OBJECT, offsetof(PyCoroObject, cr_frame), READONLY},

{"cr_running", T_BOOL, offsetof(PyCoroObject, cr_running), READONLY},

{"cr_code", T_OBJECT, offsetof(PyCoroObject, cr_code), READONLY},

{NULL} /* Sentinel */

};

PyDoc_STRVAR(coro_send_doc,

"send(arg) -> send 'arg' into coroutine,\n\

return next iterated value or raise StopIteration.");

PyDoc_STRVAR(coro_throw_doc,

"throw(typ[,val[,tb]]) -> raise exception in coroutine,\n\

return next iterated value or raise StopIteration.");

PyDoc_STRVAR(coro_close_doc,

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

static PyMethodDef coro_methods[] = {

{"send",(PyCFunction)_PyGen_Send, METH_O, coro_send_doc},

{"throw",(PyCFunction)gen_throw, METH_VARARGS, coro_throw_doc},

{"close",(PyCFunction)gen_close, METH_NOARGS, coro_close_doc},

{NULL, NULL} /* Sentinel */

};

static PyAsyncMethods coro_as_async = {

(unaryfunc)coro_await, /* am_await */

0, /* am_aiter */

0 /* am_anext */

};

PyTypeObject PyCoro_Type = {

PyVarObject_HEAD_INIT(&PyType_Type, 0)

"coroutine", /* tp_name */

sizeof(PyCoroObject), /* tp_basicsize */

0, /* tp_itemsize */