/*
** barrier for assignments to closed upvalues. Because upvalues are
** shared among closures, it is impossible to know the color of all
** closures pointing to it. So, we assume that the object being assigned
** must be marked.
*/
void luaC_upvalbarrier_ (lua_State *L, UpVal *uv) {
global_State *g = G(L);
GCObject *o = gcvalue(uv->v);
lua_assert(!upisopen(uv)); /* ensured by macro luaC_upvalbarrier */
if (keepinvariant(g))
markobject(g, o);
}
/*
** open upvalues point to values in a thread, so those values should
** be marked when the thread is traversed except in the atomic phase
** (because then the value cannot be changed by the thread and the
** thread may not be traversed again)
*/
static lu_mem traverseLclosure (global_State *g, LClosure *cl) {
int i;
markobjectN(g, cl->p); /* mark its prototype */
for (i = 0; i < cl->nupvalues; i++) { /* mark its upvalues */
UpVal *uv = cl->upvals[i];
if (uv != NULL) {
if (upisopen(uv) && g->gcstate != GCSinsideatomic)
uv->u.open.touched = 1; /* can be marked in 'remarkupvals' */
else
markvalue(g, uv->v);
}
}
return sizeLclosure(cl->nupvalues);
}
void luaF_close (lua_State *L, StkId level) {
UpVal *uv;
while (L->openupval != NULL && (uv = L->openupval)->v >= level) {
lua_assert(upisopen(uv));
L->openupval = uv->u.open.next; /* remove from 'open' list */
if (uv->refcount == 0) /* no references? */
luaM_free(L, uv); /* free upvalue */
else {
setobj(L, &uv->u.value, uv->v); /* move value to upvalue slot */
uv->v = &uv->u.value; /* now current value lives here */
luaC_upvalbarrier(L, uv);
}
}
}
UpVal *luaF_findupval (lua_State *L, StkId level) {
UpVal **pp = &L->openupval;
UpVal *p;
UpVal *uv;
lua_assert(isintwups(L) || L->openupval == NULL);
while (*pp != NULL && (p = *pp)->v >= level) {
lua_assert(upisopen(p));
if (p->v == level) /* found a corresponding upvalue? */
return p; /* return it */
pp = &p->u.open.next;
}
/* not found: create a new upvalue */
uv = luaM_new(L, UpVal);
uv->refcount = 0;
uv->u.open.next = *pp; /* link it to list of open upvalues */
uv->u.open.touched = 1;
*pp = uv;
uv->v = level; /* current value lives in the stack */
if (!isintwups(L)) { /* thread not in list of threads with upvalues? */
L->twups = G(L)->twups; /* link it to the list */
G(L)->twups = L;
}
return uv;
}
void luaC_upvdeccount (lua_State *L, UpVal *uv) {
lua_assert(uv->refcount > 0);
uv->refcount--;
if (uv->refcount == 0 && !upisopen(uv))
luaM_free(L, uv);
}
void luaF_unlinkupval (UpVal *uv) {
lua_assert(upisopen(uv));
*uv->u.open.previous = uv->u.open.next;
if (uv->u.open.next)
uv->u.open.next->u.open.previous = uv->u.open.previous;
}
