Patch #957398: Add public API for Generator Object/Type.

1 files changed, 129 insertions, 0 deletions

diff --git a/Objects/genobject.c b/Objects/genobject.c
new file mode 100644
index 0000000..0f7373a
--- /dev/null
+++ b/Objects/genobject.c
@@ -0,0 +1,129 @@
+/* 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_GC_UNTRACK(gen);
+	if (gen->gi_weakreflist != NULL)
+		PyObject_ClearWeakRefs((PyObject *) gen);
+	Py_DECREF(gen->gi_frame);
+	PyObject_GC_Del(gen);
+}
+
+static PyObject *
+gen_iternext(PyGenObject *gen)
+{
+	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->f_stacktop == NULL)
+		return NULL;
+
+	/* 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_EvaluateFrame((PyObject *)f);
+	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. */
+	Py_XDECREF(f->f_back);
+	f->f_back = NULL;
+
+	/* 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;
+	}
+
+	return result;
+}
+
+static PyObject *
+gen_getiter(PyObject *gen)
+{
+	Py_INCREF(gen);
+	return gen;
+}
+
+static PyMemberDef gen_memberlist[] = {
+	{"gi_frame",	T_OBJECT, offsetof(PyGenObject, gi_frame),	RO},
+	{"gi_running",	T_INT,    offsetof(PyGenObject, gi_running),	RO},
+	{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 */
+	(getiterfunc)gen_getiter,		/* tp_iter */
+	(iternextfunc)gen_iternext,		/* tp_iternext */
+	0,					/* tp_methods */
+	gen_memberlist,				/* tp_members */
+	0,					/* tp_getset */
+	0,					/* tp_base */
+	0,					/* tp_dict */
+};
+
+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;
+}