[Python-Dev] iterzip() (original) (raw)

Martin v. Loewis martin@v.loewis.de
30 Apr 2002 19:28:38 +0200

Guido van Rossum <guido@python.org> writes:

> That could happen in gen0 already: when traversing an object, watch > whether it contains any tracked objects. If it doesn't, invoke > tpisimmutable, if that returns true, untrack it.

Unfortunately, the visit API doesn't make it easy to watch this; a tuple calls visit() on its items but learns nothing except whether it failed. (I've never seen a visit() implementation that could fail, so I'm not sure even why the return code exists.)

However, the visit function could record this result. For example, for move_root_reachable:

struct m_r_r{ PyGC_Head *reachable; int immutable_nonnested; };

static int visit_move(PyObject *op, struct m_r_r *tolist) { if(PyObject_IS_GC(op)){ if(GC_is_tracked(op)) m_r_r->tolist.immutable_nonnested = 0; ... } return 0; }

static void move_root_reachable(PyGC_Head reachable) { struct m_r_r my_m_r_r; my_m_r_r.reachable = reachable; for (; gc != reachable; gc=gc->gc.gc_next) { / careful, reachable list is growing here */ PyObject *op = FROM_GC(gc); traverse = op->ob_type->tp_traverse; my_m_r_r.immutable_nonnested = 1; (void) traverse(op, (visitproc)visit_move, (void *)reachable); if(my_m_r_r.immutable_nonnested && op->ob_type->tp_immutable(op)){ GC_Untrack(op); } } }

I'm not sure whether move_root_reachable would be the right place to untrack those objects, but the information is all there.

Regards, Martin