mirror of https://github.com/python/cpython
358 lines
8.9 KiB
C
358 lines
8.9 KiB
C
/* 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 *self = (PyObject *) gen;
|
|
|
|
_PyObject_GC_UNTRACK(gen);
|
|
|
|
if (gen->gi_weakreflist != NULL)
|
|
PyObject_ClearWeakRefs((PyObject *) gen);
|
|
|
|
|
|
_PyObject_GC_TRACK(self);
|
|
|
|
if (gen->gi_frame->f_stacktop!=NULL) {
|
|
/* Generator is paused, so we need to close */
|
|
gen->ob_type->tp_del(self);
|
|
if (self->ob_refcnt > 0)
|
|
return; /* resurrected. :( */
|
|
}
|
|
|
|
_PyObject_GC_UNTRACK(self);
|
|
Py_XDECREF(gen->gi_frame);
|
|
PyObject_GC_Del(gen);
|
|
}
|
|
|
|
|
|
static PyObject *
|
|
gen_send_ex(PyGenObject *gen, PyObject *arg, int exc)
|
|
{
|
|
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 ((PyObject *)f == Py_None || f->f_stacktop == NULL) {
|
|
/* Only set exception if called from send() */
|
|
if (arg && !exc) PyErr_SetNone(PyExc_StopIteration);
|
|
return NULL;
|
|
}
|
|
|
|
if (f->f_lasti == -1) {
|
|
if (arg && arg != Py_None) {
|
|
PyErr_SetString(PyExc_TypeError,
|
|
"can't send non-None value to a just-started generator");
|
|
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 == Py_None && f->f_stacktop == NULL) {
|
|
Py_DECREF(result);
|
|
result = NULL;
|
|
/* Set exception if not called by gen_iternext() */
|
|
if (arg) PyErr_SetNone(PyExc_StopIteration);
|
|
}
|
|
|
|
if (!result || f->f_stacktop == NULL) {
|
|
/* generator can't be rerun, so release the frame */
|
|
Py_DECREF(f);
|
|
gen->gi_frame = (PyFrameObject *)Py_None;
|
|
Py_INCREF(Py_None);
|
|
}
|
|
|
|
return result;
|
|
}
|
|
|
|
PyDoc_STRVAR(send_doc,
|
|
"send(arg) -> send 'arg' into generator, return next yielded value or raise StopIteration.");
|
|
|
|
static PyObject *
|
|
gen_send(PyGenObject *gen, PyObject *arg)
|
|
{
|
|
return gen_send_ex(gen, arg, 0);
|
|
}
|
|
|
|
PyDoc_STRVAR(close_doc,
|
|
"close(arg) -> raise GeneratorExit inside generator.");
|
|
|
|
static PyObject *
|
|
gen_close(PyGenObject *gen, PyObject *args)
|
|
{
|
|
PyObject *retval;
|
|
PyErr_SetNone(PyExc_GeneratorExit);
|
|
retval = gen_send_ex(gen, Py_None, 1);
|
|
if (retval) {
|
|
Py_DECREF(retval);
|
|
PyErr_SetString(PyExc_RuntimeError,
|
|
"generator ignored GeneratorExit");
|
|
return NULL;
|
|
}
|
|
if ( PyErr_ExceptionMatches(PyExc_StopIteration)
|
|
|| PyErr_ExceptionMatches(PyExc_GeneratorExit) )
|
|
{
|
|
PyErr_Clear(); /* ignore these errors */
|
|
Py_INCREF(Py_None);
|
|
return Py_None;
|
|
}
|
|
return NULL;
|
|
}
|
|
|
|
static void
|
|
gen_del(PyObject *self)
|
|
{
|
|
PyObject *res;
|
|
PyObject *error_type, *error_value, *error_traceback;
|
|
PyGenObject *gen = (PyGenObject *)self;
|
|
|
|
if ((PyObject *)gen->gi_frame == Py_None || gen->gi_frame->f_stacktop==NULL)
|
|
/* Generator isn't paused, so no need to close */
|
|
return;
|
|
|
|
/* Temporarily resurrect the object. */
|
|
assert(self->ob_refcnt == 0);
|
|
self->ob_refcnt = 1;
|
|
|
|
/* Save the current exception, if any. */
|
|
PyErr_Fetch(&error_type, &error_value, &error_traceback);
|
|
|
|
res = gen_close((PyGenObject *)self, NULL);
|
|
|
|
if (res == NULL)
|
|
PyErr_WriteUnraisable((PyObject *)self);
|
|
else
|
|
Py_DECREF(res);
|
|
|
|
/* Restore the saved exception. */
|
|
PyErr_Restore(error_type, error_value, error_traceback);
|
|
|
|
/* Undo the temporary resurrection; can't use DECREF here, it would
|
|
* cause a recursive call.
|
|
*/
|
|
assert(self->ob_refcnt > 0);
|
|
if (--self->ob_refcnt == 0)
|
|
return; /* this is the normal path out */
|
|
|
|
/* close() resurrected it! Make it look like the original Py_DECREF
|
|
* never happened.
|
|
*/
|
|
{
|
|
int refcnt = self->ob_refcnt;
|
|
_Py_NewReference(self);
|
|
self->ob_refcnt = refcnt;
|
|
}
|
|
assert(!PyType_IS_GC(self->ob_type) ||
|
|
_Py_AS_GC(self)->gc.gc_refs != _PyGC_REFS_UNTRACKED);
|
|
|
|
/* If Py_REF_DEBUG, _Py_NewReference bumped _Py_RefTotal, so
|
|
* we need to undo that. */
|
|
_Py_DEC_REFTOTAL;
|
|
/* If Py_TRACE_REFS, _Py_NewReference re-added self to the object
|
|
* chain, so no more to do there.
|
|
* If COUNT_ALLOCS, the original decref bumped tp_frees, and
|
|
* _Py_NewReference bumped tp_allocs: both of those need to be
|
|
* undone.
|
|
*/
|
|
#ifdef COUNT_ALLOCS
|
|
--self->ob_type->tp_frees;
|
|
--self->ob_type->tp_allocs;
|
|
#endif
|
|
}
|
|
|
|
|
|
|
|
PyDoc_STRVAR(throw_doc,
|
|
"throw(typ[,val[,tb]]) -> raise exception in generator, return next yielded value or raise StopIteration.");
|
|
|
|
static PyObject *
|
|
gen_throw(PyGenObject *gen, PyObject *args)
|
|
{
|
|
PyObject *typ;
|
|
PyObject *tb = NULL;
|
|
PyObject *val = NULL;
|
|
|
|
if (!PyArg_ParseTuple(args, "O|OO:throw", &typ, &val, &tb))
|
|
return NULL;
|
|
|
|
/* First, check the traceback argument, replacing None with
|
|
NULL. */
|
|
if (tb == Py_None) {
|
|
Py_DECREF(tb);
|
|
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 (PyClass_Check(typ)) {
|
|
PyErr_NormalizeException(&typ, &val, &tb);
|
|
}
|
|
|
|
else if (PyInstance_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 = (PyObject*) ((PyInstanceObject*)typ)->in_class;
|
|
Py_INCREF(typ);
|
|
}
|
|
}
|
|
else {
|
|
/* Not something you can raise. throw() fails. */
|
|
PyErr_Format(PyExc_TypeError,
|
|
"exceptions must be classes, or instances, not %s",
|
|
typ->ob_type->tp_name);
|
|
goto failed_throw;
|
|
}
|
|
|
|
PyErr_Restore(typ,val,tb);
|
|
return gen_send_ex(gen, Py_None, 1);
|
|
|
|
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_iternext(PyGenObject *gen)
|
|
{
|
|
return gen_send_ex(gen, NULL, 0);
|
|
}
|
|
|
|
|
|
static PyMemberDef gen_memberlist[] = {
|
|
{"gi_frame", T_OBJECT, offsetof(PyGenObject, gi_frame), RO},
|
|
{"gi_running", T_INT, offsetof(PyGenObject, gi_running), RO},
|
|
{NULL} /* Sentinel */
|
|
};
|
|
|
|
static PyMethodDef gen_methods[] = {
|
|
{"send",(PyCFunction)gen_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 = {
|
|
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 */
|
|
gen_methods, /* tp_methods */
|
|
gen_memberlist, /* tp_members */
|
|
0, /* 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 */
|
|
gen_del, /* tp_del */
|
|
};
|
|
|
|
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;
|
|
}
|