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https://github.com/python/cpython
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123 lines
2.9 KiB
C
123 lines
2.9 KiB
C
/* Generator object implementation */
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#include "Python.h"
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#include "frameobject.h"
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#include "genobject.h"
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#include "ceval.h"
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#include "structmember.h"
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static int
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gen_traverse(PyGenObject *gen, visitproc visit, void *arg)
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{
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return visit((PyObject *)gen->gi_frame, arg);
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}
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static void
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gen_dealloc(PyGenObject *gen)
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{
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_PyObject_GC_UNTRACK(gen);
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if (gen->gi_weakreflist != NULL)
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PyObject_ClearWeakRefs((PyObject *) gen);
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Py_DECREF(gen->gi_frame);
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PyObject_GC_Del(gen);
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}
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static PyObject *
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gen_iternext(PyGenObject *gen)
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{
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PyThreadState *tstate = PyThreadState_GET();
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PyFrameObject *f = gen->gi_frame;
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PyObject *result;
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if (gen->gi_running) {
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PyErr_SetString(PyExc_ValueError,
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"generator already executing");
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return NULL;
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}
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if (f->f_stacktop == NULL)
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return NULL;
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/* Generators always return to their most recent caller, not
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* necessarily their creator. */
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Py_XINCREF(tstate->frame);
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assert(f->f_back == NULL);
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f->f_back = tstate->frame;
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gen->gi_running = 1;
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result = PyEval_EvalFrame(f);
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gen->gi_running = 0;
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/* Don't keep the reference to f_back any longer than necessary. It
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* may keep a chain of frames alive or it could create a reference
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* cycle. */
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assert(f->f_back != NULL);
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Py_CLEAR(f->f_back);
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/* If the generator just returned (as opposed to yielding), signal
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* that the generator is exhausted. */
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if (result == Py_None && f->f_stacktop == NULL) {
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Py_DECREF(result);
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result = NULL;
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}
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return result;
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}
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static PyMemberDef gen_memberlist[] = {
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{"gi_frame", T_OBJECT, offsetof(PyGenObject, gi_frame), RO},
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{"gi_running", T_INT, offsetof(PyGenObject, gi_running), RO},
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{NULL} /* Sentinel */
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};
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PyTypeObject PyGen_Type = {
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PyObject_HEAD_INIT(&PyType_Type)
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0, /* ob_size */
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"generator", /* tp_name */
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sizeof(PyGenObject), /* tp_basicsize */
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0, /* tp_itemsize */
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/* methods */
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(destructor)gen_dealloc, /* tp_dealloc */
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0, /* tp_print */
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0, /* tp_getattr */
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0, /* tp_setattr */
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0, /* tp_compare */
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0, /* tp_repr */
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0, /* tp_as_number */
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0, /* tp_as_sequence */
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0, /* tp_as_mapping */
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0, /* tp_hash */
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0, /* tp_call */
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0, /* tp_str */
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PyObject_GenericGetAttr, /* tp_getattro */
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0, /* tp_setattro */
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0, /* tp_as_buffer */
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Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC,/* tp_flags */
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0, /* tp_doc */
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(traverseproc)gen_traverse, /* tp_traverse */
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0, /* tp_clear */
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0, /* tp_richcompare */
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offsetof(PyGenObject, gi_weakreflist), /* tp_weaklistoffset */
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PyObject_SelfIter, /* tp_iter */
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(iternextfunc)gen_iternext, /* tp_iternext */
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0, /* tp_methods */
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gen_memberlist, /* tp_members */
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0, /* tp_getset */
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0, /* tp_base */
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0, /* tp_dict */
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};
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PyObject *
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PyGen_New(PyFrameObject *f)
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{
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PyGenObject *gen = PyObject_GC_New(PyGenObject, &PyGen_Type);
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if (gen == NULL) {
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Py_DECREF(f);
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return NULL;
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}
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gen->gi_frame = f;
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gen->gi_running = 0;
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gen->gi_weakreflist = NULL;
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_PyObject_GC_TRACK(gen);
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return (PyObject *)gen;
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}
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