/*
** 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;
}
}
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;
}
case LUA_TUSERDATA: {
luaM_freemem(L, o, sizeudata(gco2u(o)));
break;
}
default:
lua_assert(0);
}
}
void reallymarkobject (global_State *g, GCObject *o) {
#else
static void reallymarkobject (global_State *g, GCObject *o) {
#endif /* LUAPLUS_EXTENSIONS */
lua_assert(iswhite(o) && !isdead(g, o));
white2gray(o);
switch (o->gch.tt) {
case LUA_TSTRING: {
return;
}
#if LUA_WIDESTRING
case LUA_TWSTRING: {
return;
}
#endif /* LUA_WIDESTRING */
case LUA_TUSERDATA: {
Table *mt = gco2u(o)->metatable;
gray2black(o); /* udata are never gray */
if (mt) markobject(g, mt);
markobject(g, gco2u(o)->env);
return;
}
case LUA_TUPVAL: {
UpVal *uv = gco2uv(o);
markvalue(g, uv->v);
if (uv->v == &uv->u.value) /* closed? */
gray2black(o); /* open upvalues are never black */
return;
}
case LUA_TFUNCTION: {
gco2cl(o)->c.gclist = g->gray;
g->gray = o;
break;
}
case LUA_TTABLE: {
gco2h(o)->gclist = g->gray;
g->gray = o;
break;
}
case LUA_TTHREAD: {
gco2th(o)->gclist = g->gray;
g->gray = o;
break;
}
case LUA_TPROTO: {
gco2p(o)->gclist = g->gray;
g->gray = o;
break;
}
default: lua_assert(0);
}
}
static void freeobj (lua_State *L, GCObject *o) {
global_State *g = G(L);
lua_assert(is_robj(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;
}
case LUA_TUSERDATA: {
const Udata *udata = rawgco2u(o);
const TValue *tm = fasttm(L, udata->uv.metatable, TM_GC);
if (tm != NULL) {
lu_byte oldah = L->allowhook;
lu_mem oldt = g->GCthreshold;
L->allowhook = 0; /* stop debug hooks during GC tag method */
g->GCthreshold = 2*g->totalbytes; /* avoid GC steps */
setobj2s(L, L->top, tm);
setuvalue(L, L->top+1, udata);
L->top += 2;
luaD_call(L, L->top - 2, 0);
L->allowhook = oldah; /* restore hooks */
g->GCthreshold = oldt; /* restore threshold */
}
luaM_freemem(L, o, sizeudata(gco2u(o)));
break;
}
default:
lua_assert(0);
}
}
void rstack_reject (lua_State *L, GCObject *src) {
RStack *rs = rstack(L);
RObject *robj = rstack_getrobj(rs, src);
lua_assert(robj && src == robj->body);
luaC_link(L, src, src->gch.tt);
switch(src->gch.tt) {
case LUA_TTABLE:
luaH_reject(L, gco2h(src));
break;
case LUA_TUSERDATA:
luaS_rejectu(L, rawgco2u(src));
break;
// TODO: implement
default:
lua_assert(0);
}
robj->body = NULL;
}
/*
** traverse one gray object, turning it to black.
** Returns `quantity' traversed.
*/
static l_mem propagatemark (global_State *g) {
GCObject *o = g->gray;
lua_assert(isgray(o));
gray2black(o);
switch (o->gch.tt) {
case LUA_TTABLE: {
Table *h = gco2h(o);
g->gray = h->gclist;
if (traversetable(g, h)) /* table is weak? */
black2gray(o); /* keep it gray */
return sizeof(Table) + sizeof(TValue) * h->sizearray +
sizeof(Node) * sizenode(h);
}
case LUA_TFUNCTION: {
Closure *cl = gco2cl(o);
g->gray = cl->c.gclist;
traverseclosure(g, cl);
return (cl->c.isC) ? sizeCclosure(cl->c.nupvalues) :
sizeLclosure(cl->l.nupvalues);
}
case LUA_TTHREAD: {
lua_State *th = gco2th(o);
g->gray = th->gclist;
th->gclist = g->grayagain;
g->grayagain = o;
black2gray(o);
traversestack(g, th);
return sizeof(lua_State) + sizeof(TValue) * th->stacksize +
sizeof(CallInfo) * th->size_ci;
}
case LUA_TPROTO: {
Proto *p = gco2p(o);
g->gray = p->gclist;
traverseproto(g, p);
return sizeof(Proto) + sizeof(Instruction) * p->sizecode +
sizeof(Proto *) * p->sizep +
sizeof(TValue) * p->sizek +
sizeof(int) * p->sizelineinfo +
sizeof(LocVar) * p->sizelocvars +
sizeof(TString *) * p->sizeupvalues;
}
default: lua_assert(0); return 0;
}
}
static void reallymarkobject (global_State *g, GCObject *o) {
lua_assert(iswhite(o) && !isdead(g, o));
white2gray(o);// 先将白变灰
switch (o->gch.tt) {// 根据不同类型进行不同的操作
case LUA_TSTRING: {
return; // 不通过gc管理
}
case LUA_TUSERDATA: {
Table *mt = gco2u(o)->metatable;
gray2black(o); /* udata are never gray */
if (mt) markobject(g, mt);
markobject(g, gco2u(o)->env);
return;
}
case LUA_TUPVAL: {
UpVal *uv = gco2uv(o);
markvalue(g, uv->v);
if (uv->v == &uv->u.value) /* closed? */
gray2black(o); /* open upvalues are never black */
return;
}
case LUA_TFUNCTION: {
gco2cl(o)->c.gclist = g->gray;
g->gray = o;
break;
}
case LUA_TTABLE: {
gco2h(o)->gclist = g->gray;
g->gray = o;
break;
}
case LUA_TTHREAD: {
gco2th(o)->gclist = g->gray;
g->gray = o;
break;
}
case LUA_TPROTO: {
gco2p(o)->gclist = g->gray;
g->gray = o;
break;
}
default: lua_assert(0);
}
}
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;
}