ref: d4bc9052beb3305d64a353a16641740380eb87af
dir: /sys/src/cmd/python/Objects/genobject.c/
/* Generator object implementation */ #include "Python.h" #include "frameobject.h" #include "genobject.h" #include "ceval.h" #include "structmember.h" #include "opcode.h" static int gen_traverse(PyGenObject *gen, visitproc visit, void *arg) { Py_VISIT((PyObject *)gen->gi_frame); return 0; } 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 (gen->gi_frame != NULL && 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_CLEAR(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 (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 == 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 = NULL; } return result; } PyDoc_STRVAR(send_doc, "send(arg) -> send 'arg' into generator,\n\ 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 (gen->gi_frame == NULL || 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(gen, NULL); if (res == NULL) PyErr_WriteUnraisable(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. */ { Py_ssize_t 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,\n\ 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_UnpackTuple(args, "throw", 1, 3, &typ, &val, &tb)) return NULL; /* 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); } } /* Allow raising builtin string exceptions */ else if (!PyString_CheckExact(typ)) { /* 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; } int PyGen_NeedsFinalizing(PyGenObject *gen) { int i; PyFrameObject *f = gen->gi_frame; if (f == NULL || f->f_stacktop == NULL || f->f_iblock <= 0) return 0; /* no frame or empty blockstack == no finalization */ /* Any block type besides a loop requires cleanup. */ i = f->f_iblock; while (--i >= 0) { if (f->f_blockstack[i].b_type != SETUP_LOOP) return 1; } /* No blocks except loops, it's safe to skip finalization. */ return 0; }