/*
** function to be used with macro "fasttm": optimized for absence of
** tag methods
*/
const TValue *luaT_gettm (Table *events, TMS event, TString *ename)
{
const TValue *tm = luaR_isrotable(events) ? luaH_getstr_ro(events, ename) : luaH_getstr(events, ename);
lua_assert(event <= TM_EQ);
if (ttisnil(tm)) { /* no tag method? */
if (!luaR_isrotable(events))
events->flags |= cast_byte(1u<<event); /* cache this fact */
return NULL;
} else return tm;
}
static void reallymarkobject (global_State *g, GCObject *o) {
lua_assert(iswhite(o) && !isdead(g, o));
white2gray(o);
switch (o->gch.tt) {
case LUA_TSTRING: {
return;
}
case LUA_TUSERDATA: {
Table *mt = gco2u(o)->metatable;
gray2black(o); /* udata are never gray */
if (mt && !luaR_isrotable(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 int traversetable (global_State *g, Table *h) {
int i;
int weakkey = 0;
int weakvalue = 0;
const TValue *mode;
if (h->metatable && !luaR_isrotable(h->metatable))
markobject(g, h->metatable);
mode = gfasttm(g, h->metatable, TM_MODE);
if (mode && ttisstring(mode)) { /* is there a weak mode? */
weakkey = (c_strchr(svalue(mode), 'k') != NULL);
weakvalue = (c_strchr(svalue(mode), 'v') != NULL);
if (weakkey || weakvalue) { /* is really weak? */
h->marked &= ~(KEYWEAK | VALUEWEAK); /* clear bits */
h->marked |= cast_byte((weakkey << KEYWEAKBIT) |
(weakvalue << VALUEWEAKBIT));
h->gclist = g->weak; /* must be cleared after GC, ... */
g->weak = obj2gco(h); /* ... so put in the appropriate list */
}
}
if (weakkey && weakvalue) return 1;
if (!weakvalue) {
i = h->sizearray;
while (i--)
markvalue(g, &h->array[i]);
}
i = sizenode(h);
while (i--) {
Node *n = gnode(h, i);
lua_assert(ttype(gkey(n)) != LUA_TDEADKEY || ttisnil(gval(n)));
if (ttisnil(gval(n)))
removeentry(n); /* remove empty entries */
else {
lua_assert(!ttisnil(gkey(n)));
if (!weakkey) markvalue(g, gkey(n));
if (!weakvalue) markvalue(g, gval(n));
}
}
return weakkey || weakvalue;
}
const TValue *luaT_gettmbyobj (lua_State *L, const TValue *o, TMS event)
{
Table *mt;
switch (ttype(o)) {
case LUA_TTABLE:
mt = hvalue(o)->metatable;
break;
case LUA_TROTABLE:
mt = (Table *)luaR_getmeta(rvalue(o));
break;
case LUA_TUSERDATA:
mt = uvalue(o)->metatable;
break;
default:
mt = G(L)->mt[ttype(o)];
}
if (!mt)
return luaO_nilobject;
else if (luaR_isrotable(mt))
return luaH_getstr_ro(mt, G(L)->tmname[event]);
else
return luaH_getstr(mt, G(L)->tmname[event]);
}
static void markmt (global_State *g) {
int i;
for (i=0; i<NUM_TAGS; i++)
if (g->mt[i] && !luaR_isrotable(g->mt[i])) markobject(g, g->mt[i]);
}
