/*
** clear collected entries from weaktables
*/
static void cleartable (GCObject *l) {
while (l) {
Table *h = gco2h(l);
int i = h->sizearray;
lua_assert(testbit(h->marked, VALUEWEAKBIT) ||
testbit(h->marked, KEYWEAKBIT));
if (testbit(h->marked, VALUEWEAKBIT)) {
while (i--) {
TValue *o = &h->array[i];
if (iscleared(o, 0)) /* value was collected? */
setnilvalue(o); /* remove value */
}
}
i = sizenode(h);
while (i--) {
Node *n = gnode(h, i);
if (!ttisnil(gval(n)) && /* non-empty entry? */
(iscleared(key2tval(n), 1) || iscleared(gval(n), 0))) {
setnilvalue(gval(n)); /* remove value ... */
removeentry(n); /* remove entry from table */
}
}
l = h->gclist;
}
}
/*
** clear entries with unmarked values from all weaktables in list 'l' up
** to element 'f'
*/
static void clearvalues (global_State *g, GCObject *l, GCObject *f) {
for (; l != f; l = gco2t(l)->gclist) {
Table *h = gco2t(l);
Node *n, *limit = gnodelast(h);
unsigned int i;
for (i = 0; i < h->sizearray; i++) {
TValue *o = &h->array[i];
if (iscleared(g, o)) /* value was collected? */
setnilvalue(o); /* remove value */
}
for (n = gnode(h, 0); n < limit; n++) {
if (!ttisnil(gval(n)) && iscleared(g, gval(n))) {
setnilvalue(gval(n)); /* remove value ... */
removeentry(n); /* and remove entry from table */
}
}
}
}
/*
** clear entries with unmarked keys from all weaktables in list 'l' up
** to element 'f'
*/
static void clearkeys (global_State *g, GCObject *l, GCObject *f) {
for (; l != f; l = gco2t(l)->gclist) {
Table *h = gco2t(l);
Node *n, *limit = gnodelast(h);
for (n = gnode(h, 0); n < limit; n++) {
if (!ttisnil(gval(n)) && (iscleared(g, gkey(n)))) {
setnilvalue(gval(n)); /* remove value ... */
removeentry(n); /* and remove entry from table */
}
}
}
}
/*
** Traverse a table with weak values and link it to proper list. During
** propagate phase, keep it in 'grayagain' list, to be revisited in the
** atomic phase. In the atomic phase, if table has any white value,
** put it in 'weak' list, to be cleared.
*/
static void traverseweakvalue (global_State *g, Table *h) {
Node *n, *limit = gnodelast(h);
/* if there is array part, assume it may have white values (it is not
worth traversing it now just to check) */
int hasclears = (h->sizearray > 0);
for (n = gnode(h, 0); n < limit; n++) { /* traverse hash part */
checkdeadkey(n);
if (ttisnil(gval(n))) /* entry is empty? */
removeentry(n); /* remove it */
else {
lua_assert(!ttisnil(gkey(n)));
markvalue(g, gkey(n)); /* mark key */
if (!hasclears && iscleared(g, gval(n))) /* is there a white value? */
hasclears = 1; /* table will have to be cleared */
}
}
if (g->gcstate == GCSpropagate)
linkgclist(h, g->grayagain); /* must retraverse it in atomic phase */
else if (hasclears)
linkgclist(h, g->weak); /* has to be cleared later */
}
static void traverseweakvalue (global_State *g, Table *h) {
Node *n, *limit = gnodelast(h);
/* if there is array part, assume it may have white values (do not
traverse it just to check) */
int hasclears = (h->sizearray > 0);
for (n = gnode(h, 0); n < limit; n++) {
checkdeadkey(n);
if (ttisnil(gval(n))) /* entry is empty? */
removeentry(n); /* remove it */
else {
lua_assert(!ttisnil(gkey(n)));
markvalue(g, gkey(n)); /* mark key */
if (!hasclears && iscleared(g, gval(n))) /* is there a white value? */
hasclears = 1; /* table will have to be cleared */
}
}
if (hasclears)
linktable(h, &g->weak); /* has to be cleared later */
else /* no white values */
linktable(h, &g->grayagain); /* no need to clean */
}
/*
** Traverse an ephemeron table and link it to proper list. Returns true
** iff any object was marked during this traversal (which implies that
** convergence has to continue). During propagation phase, keep table
** in 'grayagain' list, to be visited again in the atomic phase. In
** the atomic phase, if table has any white->white entry, it has to
** be revisited during ephemeron convergence (as that key may turn
** black). Otherwise, if it has any white key, table has to be cleared
** (in the atomic phase).
*/
static int traverseephemeron (global_State *g, Table *h) {
int marked = 0; /* true if an object is marked in this traversal */
int hasclears = 0; /* true if table has white keys */
int hasww = 0; /* true if table has entry "white-key -> white-value" */
Node *n, *limit = gnodelast(h);
unsigned int i;
/* traverse array part */
for (i = 0; i < h->sizearray; i++) {
if (valiswhite(&h->array[i])) {
marked = 1;
reallymarkobject(g, gcvalue(&h->array[i]));
}
}
/* traverse hash part */
for (n = gnode(h, 0); n < limit; n++) {
checkdeadkey(n);
if (ttisnil(gval(n))) /* entry is empty? */
removeentry(n); /* remove it */
else if (iscleared(g, gkey(n))) { /* key is not marked (yet)? */
hasclears = 1; /* table must be cleared */
if (valiswhite(gval(n))) /* value not marked yet? */
hasww = 1; /* white-white entry */
}
else if (valiswhite(gval(n))) { /* value not marked yet? */
marked = 1;
reallymarkobject(g, gcvalue(gval(n))); /* mark it now */
}
}
/* link table into proper list */
if (g->gcstate == GCSpropagate)
linkgclist(h, g->grayagain); /* must retraverse it in atomic phase */
else if (hasww) /* table has white->white entries? */
linkgclist(h, g->ephemeron); /* have to propagate again */
else if (hasclears) /* table has white keys? */
linkgclist(h, g->allweak); /* may have to clean white keys */
return marked;
}
static int traverseephemeron (global_State *g, Table *h) {
int marked = 0; /* true if an object is marked in this traversal */
int hasclears = 0; /* true if table has white keys */
int prop = 0; /* true if table has entry "white-key -> white-value" */
Node *n, *limit = gnodelast(h);
int i;
/* traverse array part (numeric keys are 'strong') */
for (i = 0; i < h->sizearray; i++) {
if (valiswhite(&h->array[i])) {
marked = 1;
reallymarkobject(g, gcvalue(&h->array[i]));
}
}
/* traverse hash part */
for (n = gnode(h, 0); n < limit; n++) {
checkdeadkey(n);
if (ttisnil(gval(n))) /* entry is empty? */
removeentry(n); /* remove it */
else if (iscleared(g, gkey(n))) { /* key is not marked (yet)? */
hasclears = 1; /* table must be cleared */
if (valiswhite(gval(n))) /* value not marked yet? */
prop = 1; /* must propagate again */
}
else if (valiswhite(gval(n))) { /* value not marked yet? */
marked = 1;
reallymarkobject(g, gcvalue(gval(n))); /* mark it now */
}
}
if (prop)
linktable(h, &g->ephemeron); /* have to propagate again */
else if (hasclears) /* does table have white keys? */
linktable(h, &g->allweak); /* may have to clean white keys */
else /* no white keys */
linktable(h, &g->grayagain); /* no need to clean */
return marked;
}
static void cleartable (lua_State *L, GCObject *l) {
#else
static void cleartable (GCObject *l) {
#endif /* LUA_REFCOUNT */
while (l) {
Table *h = gco2h(l);
int i = h->sizearray;
lua_assert(testbit(h->marked, VALUEWEAKBIT) ||
testbit(h->marked, KEYWEAKBIT));
if (testbit(h->marked, VALUEWEAKBIT)) {
while (i--) {
TValue *o = &h->array[i];
#if LUA_REFCOUNT
if (iscleared(o, 0)) { /* value was collected? */
if (iscollectable(o))
o->value.gc->gch.ref--;
setnilvalue2n(l, o); /* remove value */
}
#else
if (iscleared(o, 0)) /* value was collected? */
setnilvalue(o); /* remove value */
#endif /* LUA_REFCOUNT */
}
}
i = sizenode(h);
while (i--) {
Node *n = gnode(h, i);
if (!ttisnil(gval(n)) && /* non-empty entry? */
(iscleared(key2tval(n), 1) || iscleared(gval(n), 0))) {
#if LUA_REFCOUNT
if (iscollectable(gval(n)))
gval(n)->value.gc->gch.ref--;
setnilvalue2n(L, gval(n)); /* remove value ... */
#else
setnilvalue(gval(n)); /* remove value ... */
#endif /* LUA_REFCOUNT */
removeentry(n); /* remove entry from table */
}
}
l = h->gclist;
}
}
static void freeobj (lua_State *L, GCObject *o) {
switch (o->gch.tt) {
case LUA_TPROTO: luaF_freeproto(L, gco2p(o)); break;
case LUA_TFUNCTION: luaF_freeclosure(L, gco2cl(o)); break;
case LUA_TUPVAL: luaF_freeupval(L, gco2uv(o)); break;
case LUA_TTABLE: luaH_free(L, gco2h(o)); break;
case LUA_TTHREAD: {
lua_assert(gco2th(o) != L && gco2th(o) != G(L)->mainthread);
luaE_freethread(L, gco2th(o));
break;
}
case LUA_TSTRING: {
G(L)->strt.nuse--;
luaM_freemem(L, o, sizestring(gco2ts(o)));
break;
}
#if LUA_WIDESTRING
case LUA_TWSTRING: {
G(L)->strt.nuse--;
luaM_freemem(L, o, sizestring(gco2ts(o)));
break;
}
#endif /* LUA_WIDESTRING */
case LUA_TUSERDATA: {
luaM_freemem(L, o, sizeudata(gco2u(o)));
break;
}
default: lua_assert(0);
}
}
#define sweepwholelist(L,p) sweeplist(L,p,MAX_LUMEM)
static GCObject **sweeplist (lua_State *L, GCObject **p, lu_mem count) {
GCObject *curr;
global_State *g = G(L);
int deadmask = otherwhite(g);
while ((curr = *p) != NULL && count-- > 0) {
if (curr->gch.tt == LUA_TTHREAD) /* sweep open upvalues of each thread */
sweepwholelist(L, &gco2th(curr)->openupval);
if ((curr->gch.marked ^ WHITEBITS) & deadmask) { /* not dead? */
lua_assert(!isdead(g, curr) || testbit(curr->gch.marked, FIXEDBIT));
makewhite(g, curr); /* make it white (for next cycle) */
p = &curr->gch.next;
}
else { /* must erase `curr' */
lua_assert(isdead(g, curr) || deadmask == bitmask(SFIXEDBIT));
#if LUA_REFCOUNT
if (curr->gch.prev)
curr->gch.prev->gch.next = curr->gch.next;
if (curr->gch.next)
curr->gch.next->gch.prev = (GCObject*)p;
#endif /* LUA_REFCOUNT */
*p = curr->gch.next;
if (curr == g->rootgc) /* is the first element of the list? */
g->rootgc = curr->gch.next; /* adjust first */
freeobj(L, curr);
}
}
return p;
}
