UpVal *luaF_findupval (lua_State *L, StkId level) {
global_State *g = G(L);
GCObject **pp = &L->openupval;
UpVal *p;
UpVal *uv;
while (*pp != NULL && (p = gco2uv(*pp))->v >= level) {
GCObject *o = obj2gco(p);
lua_assert(p->v != &p->u.value);
if (p->v == level) { /* found a corresponding upvalue? */
if (isdead(g, o)) /* is it dead? */
changewhite(o); /* resurrect it */
return p;
}
resetoldbit(o); /* may create a newer upval after this one */
pp = &p->next;
}
/* not found: create a new one */
uv = &luaC_newobj(L, LUA_TUPVAL, sizeof(UpVal), pp, 0)->uv;
uv->v = level; /* current value lives in the stack */
uv->u.l.prev = &g->uvhead; /* double link it in `uvhead' list */
uv->u.l.next = g->uvhead.u.l.next;
uv->u.l.next->u.l.prev = uv;
g->uvhead.u.l.next = uv;
lua_assert(uv->u.l.next->u.l.prev == uv && uv->u.l.prev->u.l.next == uv);
return uv;
}
/*
** call all pending finalizers
*/
static void callallpendingfinalizers (lua_State *L, int propagateerrors) {
global_State *g = G(L);
while (g->tobefnz) {
resetoldbit(g->tobefnz);
GCTM(L, propagateerrors);
}
}
/*
** if object 'o' has a finalizer, remove it from 'allgc' list (must
** search the list to find it) and link it in 'finobj' list.
*/
void luaC_checkfinalizer (lua_State *L, GCObject *o, Table *mt) {
global_State *g = G(L);
if (testbit(gch(o)->marked, SEPARATED) || /* obj. is already separated... */
isfinalized(o) || /* ... or is finalized... */
gfasttm(g, mt, TM_GC) == NULL) /* or has no finalizer? */
return; /* nothing to be done */
else { /* move 'o' to 'finobj' list */
GCObject **p;
GCheader *ho = gch(o);
if (g->sweepgc == &ho->next) { /* avoid removing current sweep object */
lua_assert(issweepphase(g));
g->sweepgc = sweeptolive(L, g->sweepgc, NULL);
}
/* search for pointer pointing to 'o' */
for (p = &g->allgc; *p != o; p = &gch(*p)->next) { /* empty */ }
*p = ho->next; /* remove 'o' from root list */
ho->next = g->finobj; /* link it in list 'finobj' */
g->finobj = o;
l_setbit(ho->marked, SEPARATED); /* mark it as such */
if (!keepinvariantout(g)) /* not keeping invariant? */
makewhite(g, o); /* "sweep" object */
else
resetoldbit(o); /* see MOVE OLD rule */
}
}
/*
** check color (and invariants) for an upvalue that was closed,
** i.e., moved into the 'allgc' list
*/
void luaC_checkupvalcolor (global_State *g, UpVal *uv) {
GCObject *o = obj2gco(uv);
lua_assert(!isblack(o)); /* open upvalues are never black */
if (isgray(o)) {
if (keepinvariant(g)) {
resetoldbit(o); /* see MOVE OLD rule */
gray2black(o); /* it is being visited now */
markvalue(g, uv->v);
}
else {
lua_assert(issweepphase(g));
makewhite(g, o);
}
}
}
/*
** if object 'o' has a finalizer, remove it from 'allgc' list (must
** search the list to find it) and link it in 'finobj' list.
*/
void luaC_checkfinalizer (lua_State *L, GCObject *o, Table *mt) {
global_State *g = G(L);
if (testbit(gch(o)->marked, SEPARATED) || /* obj. is already separated... */
isfinalized(o) || /* ... or is finalized... */
gfasttm(g, mt, TM_GC) == NULL) /* or has no finalizer? */
return; /* nothing to be done */
else { /* move 'o' to 'finobj' list */
GCObject **p;
for (p = &g->allgc; *p != o; p = &gch(*p)->next) ;
*p = gch(o)->next; /* remove 'o' from root list */
gch(o)->next = g->finobj; /* link it in list 'finobj' */
g->finobj = o;
l_setbit(gch(o)->marked, SEPARATED); /* mark it as such */
resetoldbit(o); /* see MOVE OLD rule */
}
}
