diff options
Diffstat (limited to 'Modules')
| -rw-r--r-- | Modules/gcmodule.c | 46 |
1 files changed, 31 insertions, 15 deletions
diff --git a/Modules/gcmodule.c b/Modules/gcmodule.c index 710f0ed..4bfdea6 100644 --- a/Modules/gcmodule.c +++ b/Modules/gcmodule.c @@ -139,6 +139,9 @@ gc_list_is_empty(PyGC_Head *list) return (list->gc.gc_next == list); } +#if 0 +/* This became unused after gc_list_move() was introduced. */ +/* Append `node` to `list`. */ static void gc_list_append(PyGC_Head *node, PyGC_Head *list) { @@ -147,7 +150,9 @@ gc_list_append(PyGC_Head *node, PyGC_Head *list) node->gc.gc_prev->gc.gc_next = node; list->gc.gc_prev = node; } +#endif +/* Remove `node` from the gc list it's currently in. */ static void gc_list_remove(PyGC_Head *node) { @@ -156,11 +161,29 @@ gc_list_remove(PyGC_Head *node) node->gc.gc_next = NULL; /* object is not currently tracked */ } -/* append a list onto another list, from becomes an empty list */ +/* Move `node` from the gc list it's currently in (which is not explicitly + * named here) to the end of `list`. This is semantically the same as + * gc_list_remove(node) followed by gc_list_append(node, list). + */ +static void +gc_list_move(PyGC_Head *node, PyGC_Head *list) +{ + PyGC_Head *current_prev = node->gc.gc_prev; + PyGC_Head *current_next = node->gc.gc_next; + PyGC_Head *new_prev = list->gc.gc_prev; + current_prev->gc.gc_next = current_next; + current_next->gc.gc_prev = current_prev; + node->gc.gc_next = list; + node->gc.gc_prev = new_prev; + new_prev->gc.gc_next = list->gc.gc_prev = node; +} + +/* append list `from` onto list `to`; `from` becomes an empty list */ static void gc_list_merge(PyGC_Head *from, PyGC_Head *to) { PyGC_Head *tail; + assert(from != to); if (!gc_list_is_empty(from)) { tail = to->gc.gc_prev; tail->gc.gc_next = from->gc.gc_next; @@ -295,8 +318,7 @@ visit_reachable(PyObject *op, PyGC_Head *reachable) * and move_unreachable will eventually get to it * again. */ - gc_list_remove(gc); - gc_list_append(gc, reachable); + gc_list_move(gc, reachable); gc->gc.gc_refs = 1; } /* Else there's nothing to do. @@ -368,8 +390,7 @@ move_unreachable(PyGC_Head *young, PyGC_Head *unreachable) * young if that's so, and we'll see it again. */ next = gc->gc.gc_next; - gc_list_remove(gc); - gc_list_append(gc, unreachable); + gc_list_move(gc, unreachable); gc->gc.gc_refs = GC_TENTATIVELY_UNREACHABLE; } gc = next; @@ -416,8 +437,7 @@ move_finalizers(PyGC_Head *unreachable, PyGC_Head *finalizers) next = gc->gc.gc_next; if (has_finalizer(op)) { - gc_list_remove(gc); - gc_list_append(gc, finalizers); + gc_list_move(gc, finalizers); gc->gc.gc_refs = GC_REACHABLE; } } @@ -430,8 +450,7 @@ visit_move(PyObject *op, PyGC_Head *tolist) if (PyObject_IS_GC(op)) { if (IS_TENTATIVELY_UNREACHABLE(op)) { PyGC_Head *gc = AS_GC(op); - gc_list_remove(gc); - gc_list_append(gc, tolist); + gc_list_move(gc, tolist); gc->gc.gc_refs = GC_REACHABLE; } } @@ -559,8 +578,7 @@ handle_weakrefs(PyGC_Head *unreachable, PyGC_Head *old) assert(wrasgc != next); /* wrasgc is reachable, but next isn't, so they can't be the same */ - gc_list_remove(wrasgc); - gc_list_append(wrasgc, &wrcb_to_call); + gc_list_move(wrasgc, &wrcb_to_call); } } @@ -600,8 +618,7 @@ handle_weakrefs(PyGC_Head *unreachable, PyGC_Head *old) Py_DECREF(op); if (wrcb_to_call.gc.gc_next == gc) { /* object is still alive -- move it */ - gc_list_remove(gc); - gc_list_append(gc, old); + gc_list_move(gc, old); } else ++num_freed; @@ -694,8 +711,7 @@ delete_garbage(PyGC_Head *collectable, PyGC_Head *old) } if (collectable->gc.gc_next == gc) { /* object is still alive, move it, it may die later */ - gc_list_remove(gc); - gc_list_append(gc, old); + gc_list_move(gc, old); gc->gc.gc_refs = GC_REACHABLE; } } |