563 lines
17 KiB
C
563 lines
17 KiB
C
/* Generator object implementation */
|
|
|
|
#include "Python.h"
|
|
#include "frameobject.h"
|
|
#include "structmember.h"
|
|
#include "opcode.h"
|
|
|
|
static PyObject *gen_close(PyGenObject *gen, PyObject *args);
|
|
|
|
static int
|
|
gen_traverse(PyGenObject *gen, visitproc visit, void *arg)
|
|
{
|
|
Py_VISIT((PyObject *)gen->gi_frame);
|
|
Py_VISIT(gen->gi_code);
|
|
return 0;
|
|
}
|
|
|
|
void
|
|
_PyGen_Finalize(PyObject *self)
|
|
{
|
|
PyGenObject *gen = (PyGenObject *)self;
|
|
PyObject *res;
|
|
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;
|
|
|
|
/* Save the current exception, if any. */
|
|
PyErr_Fetch(&error_type, &error_value, &error_traceback);
|
|
|
|
res = gen_close(gen, NULL);
|
|
|
|
if (res == NULL)
|
|
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);
|
|
Py_CLEAR(gen->gi_frame);
|
|
Py_CLEAR(gen->gi_code);
|
|
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 (f == NULL || 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 && f->f_stacktop == NULL) {
|
|
if (result == Py_None) {
|
|
/* Delay exception instantiation if we can */
|
|
PyErr_SetNone(PyExc_StopIteration);
|
|
} else {
|
|
PyObject *e = PyObject_CallFunctionObjArgs(
|
|
PyExc_StopIteration, result, NULL);
|
|
if (e != NULL) {
|
|
PyErr_SetObject(PyExc_StopIteration, e);
|
|
Py_DECREF(e);
|
|
}
|
|
}
|
|
Py_CLEAR(result);
|
|
}
|
|
|
|
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);
|
|
}
|
|
|
|
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)) {
|
|
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_CallFunction(meth, "");
|
|
Py_DECREF(meth);
|
|
if (retval == NULL)
|
|
return -1;
|
|
}
|
|
}
|
|
Py_XDECREF(retval);
|
|
return 0;
|
|
}
|
|
|
|
static PyObject *
|
|
gen_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 (code[f->f_lasti + 1] != 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 = gen_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);
|
|
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;
|
|
}
|
|
|
|
|
|
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, PyObject *args)
|
|
{
|
|
PyObject *typ;
|
|
PyObject *tb = NULL;
|
|
PyObject *val = NULL;
|
|
PyObject *yf = gen_yf(gen);
|
|
_Py_IDENTIFIER(throw);
|
|
|
|
if (!PyArg_UnpackTuple(args, "throw", 1, 3, &typ, &val, &tb))
|
|
return NULL;
|
|
|
|
if (yf) {
|
|
PyObject *ret;
|
|
int err;
|
|
if (PyErr_GivenExceptionMatches(typ, PyExc_GeneratorExit)) {
|
|
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);
|
|
goto throw_here;
|
|
}
|
|
if (PyGen_CheckExact(yf)) {
|
|
gen->gi_running = 1;
|
|
ret = gen_throw((PyGenObject *)yf, args);
|
|
gen->gi_running = 0;
|
|
} else {
|
|
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_CallObject(meth, args);
|
|
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 */
|
|
gen->gi_frame->f_lasti++;
|
|
if (_PyGen_FetchStopIterationValue(&val) == 0) {
|
|
ret = gen_send_ex(gen, val, 0);
|
|
Py_DECREF(val);
|
|
} else {
|
|
ret = gen_send_ex(gen, Py_None, 1);
|
|
}
|
|
}
|
|
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);
|
|
|
|
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)
|
|
{
|
|
PyObject *val = NULL;
|
|
PyObject *ret;
|
|
ret = gen_send_ex(gen, val, 0);
|
|
Py_XDECREF(val);
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* 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) {
|
|
/* avoid normalisation and take ev as value */
|
|
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>",
|
|
((PyCodeObject *)gen->gi_code)->co_name,
|
|
gen);
|
|
}
|
|
|
|
|
|
static PyObject *
|
|
gen_get_name(PyGenObject *gen)
|
|
{
|
|
PyObject *name = ((PyCodeObject *)gen->gi_code)->co_name;
|
|
Py_INCREF(name);
|
|
return name;
|
|
}
|
|
|
|
|
|
PyDoc_STRVAR(gen__name__doc__,
|
|
"Return the name of the generator's associated code object.");
|
|
|
|
static PyGetSetDef gen_getsetlist[] = {
|
|
{"__name__", (getter)gen_get_name, NULL, gen__name__doc__},
|
|
{NULL}
|
|
};
|
|
|
|
|
|
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_reserved */
|
|
(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 */
|
|
};
|
|
|
|
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;
|
|
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;
|
|
_PyObject_GC_TRACK(gen);
|
|
return (PyObject *)gen;
|
|
}
|
|
|
|
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;
|
|
}
|