/*
** 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 */
}
}
/*
** barrier that moves collector forward, that is, mark the white object
** being pointed by a black object. (If in sweep phase, clear the black
** object to white [sweep it] to avoid other barrier calls for this
** same object.)
*/
void luaC_barrier_ (lua_State *L, GCObject *o, GCObject *v) {
global_State *g = G(L);
lua_assert(isblack(o) && iswhite(v) && !isdead(g, v) && !isdead(g, o));
if (keepinvariant(g)) /* must keep invariant? */
reallymarkobject(g, v); /* restore invariant */
else { /* sweep phase */
lua_assert(issweepphase(g));
makewhite(g, o); /* mark main obj. as white to avoid other barriers */
}
}
static GCObject *udata2finalize (global_State *g) {
GCObject *o = g->tobefnz; /* get first element */
lua_assert(tofinalize(o));
g->tobefnz = o->next; /* remove it from 'tobefnz' list */
o->next = g->allgc; /* return it to 'allgc' list */
g->allgc = o;
resetbit(o->marked, FINALIZEDBIT); /* object is "normal" again */
if (issweepphase(g))
makewhite(g, o); /* "sweep" object */
return o;
}
/*
** barrier that moves collector forward, that is, mark the white object
** being pointed by a black object.
*/
void luaC_barrier_ (lua_State *L, GCObject *o, GCObject *v) {
global_State *g = G(L);
lua_assert(isblack(o) && iswhite(v) && !isdead(g, v) && !isdead(g, o));
lua_assert(isgenerational(g) || g->gcstate != GCSpause);
lua_assert(gch(o)->tt != LUA_TTABLE);
if (keepinvariant(g)) /* must keep invariant? */
reallymarkobject(g, v); /* restore invariant */
else { /* sweep phase */
lua_assert(issweepphase(g));
makewhite(g, o); /* mark main obj. as white to avoid other barriers */
}
}
/*
** 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 (tofinalize(o) || /* obj. is already marked... */
gfasttm(g, mt, TM_GC) == NULL) /* or has no finalizer? */
return; /* nothing to be done */
else { /* move 'o' to 'finobj' list */
GCObject **p;
if (issweepphase(g)) {
makewhite(g, o); /* "sweep" object 'o' */
if (g->sweepgc == &o->next) /* should not remove 'sweepgc' object */
g->sweepgc = sweeptolive(L, g->sweepgc, NULL); /* change 'sweepgc' */
}
/* search for pointer pointing to 'o' */
for (p = &g->allgc; *p != o; p = &(*p)->next) { /* empty */ }
*p = o->next; /* remove 'o' from 'allgc' list */
o->next = g->finobj; /* link it in 'finobj' list */
g->finobj = o;
l_setbit(o->marked, FINALIZEDBIT); /* mark it as such */
}
}