/* Generator object implementation */ #include "Python.h"#include "frameobject.h"#include "genobject.h"#include "ceval.h"#include "structmember.h"#include "opcode.h" static intgen_traverse(PyGenObject *gen, visitproc visit, void *arg){	Py_VISIT((PyObject *)gen->gi_frame);	return 0;} static voidgen_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 voidgen_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;} intPyGen_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;}