static int traversetable (global_State *g, Table *h) {
const TValue *mode = gfasttm(g, h->metatable, TM_MODE);
markobject(g, h->metatable);
if (mode && ttisstring(mode)) { /* is there a weak mode? */
int weakkey = (strchr(svalue(mode), 'k') != NULL);
int weakvalue = (strchr(svalue(mode), 'v') != NULL);
if (weakkey || weakvalue) { /* is really weak? */
black2gray(obj2gco(h)); /* keep table gray */
if (!weakkey) { /* strong keys? */
traverseweakvalue(g, h);
return TRAVCOST + sizenode(h);
}
else if (!weakvalue) { /* strong values? */
traverseephemeron(g, h);
return TRAVCOST + h->sizearray + sizenode(h);
}
else {
linktable(h, &g->allweak); /* nothing to traverse now */
return TRAVCOST;
}
} /* else go through */
}
traversestrongtable(g, h);
return TRAVCOST + h->sizearray + (2 * sizenode(h));
}
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 */
}
/*
** mark an object. Userdata, strings, and closed upvalues are visited
** and turned black here. Other objects are marked gray and added
** to appropriate list to be visited (and turned black) later. (Open
** upvalues are already linked in 'headuv' list.)
*/
static void reallymarkobject (global_State *g, GCObject *o) {
lu_mem size;
white2gray(o);
switch (gch(o)->tt) {
case LUA_TSHRSTR:
case LUA_TLNGSTR: {
size = sizestring(gco2ts(o));
break; /* nothing else to mark; make it black */
}
case LUA_TUSERDATA: {
Table *mt = gco2u(o)->metatable;
markobject(g, mt);
markobject(g, gco2u(o)->env);
size = sizeudata(gco2u(o));
break;
}
case LUA_TUPVAL: {
UpVal *uv = gco2uv(o);
markvalue(g, uv->v);
if (uv->v != &uv->u.value) /* open? */
return; /* open upvalues remain gray */
size = sizeof(UpVal);
break;
}
case LUA_TLCL: {
gco2lcl(o)->gclist = g->gray;
g->gray = o;
return;
}
case LUA_TCCL: {
gco2ccl(o)->gclist = g->gray;
g->gray = o;
return;
}
case LUA_TTABLE: {
linktable(gco2t(o), &g->gray);
return;
}
case LUA_TTHREAD: {
gco2th(o)->gclist = g->gray;
g->gray = o;
return;
}
case LUA_TPROTO: {
gco2p(o)->gclist = g->gray;
g->gray = o;
return;
}
default: lua_assert(0); return;
}
gray2black(o);
g->GCmemtrav += size;
}
/*
** mark an object. Userdata, strings, and closed upvalues are visited
** and turned black here. Other objects are marked gray and added
** to appropriate list to be visited (and turned black) later. (Open
** upvalues are already linked in 'headuv' list.)
*/
static void reallymarkobject (global_State *g, GCObject *o) {
reentry:
white2gray(o);
switch (gch(o)->tt) {
case LUA_TSHRSTR:
case LUA_TLNGSTR: {
gray2black(o);
g->GCmemtrav += sizestring(gco2ts(o));
break;
}
case LUA_TUSERDATA: {
TValue uvalue;
markobject(g, gco2u(o)->metatable); /* mark its metatable */
gray2black(o);
g->GCmemtrav += sizeudata(gco2u(o));
getuservalue(g->mainthread, rawgco2u(o), &uvalue);
if (valiswhite(&uvalue)) { /* markvalue(g, &uvalue); */
o = gcvalue(&uvalue);
goto reentry;
}
break;
}
case LUA_TLCL: {
gco2lcl(o)->gclist = g->gray;
g->gray = o;
break;
}
case LUA_TCCL: {
gco2ccl(o)->gclist = g->gray;
g->gray = o;
break;
}
case LUA_TTABLE: {
linktable(gco2t(o), &g->gray);
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); break;
}
}
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;
}
/*
** mark an object. Userdata and closed upvalues are visited and turned
** black here. Strings remain gray (it is the same as making them
** black). Other objects are marked gray and added to appropriate list
** to be visited (and turned black) later. (Open upvalues are already
** linked in 'headuv' list.)
*/
static void reallymarkobject (global_State *g, GCObject *o) {
lua_assert(iswhite(o) && !isdead(g, o));
white2gray(o);
switch (gch(o)->tt) {
case LUA_TSTRING: {
return; /* for strings, gray is as good as black */
}
case LUA_TUSERDATA: {
Table *mt = gco2u(o)->metatable;
markobject(g, mt);
markobject(g, gco2u(o)->env);
gray2black(o); /* all pointers marked */
return;
}
case LUA_TUPVAL: {
UpVal *uv = gco2uv(o);
markvalue(g, uv->v);
if (uv->v == &uv->u.value) /* closed? (open upvalues remain gray) */
gray2black(o); /* make it black */
return;
}
case LUA_TFUNCTION: {
gco2cl(o)->c.gclist = g->gray;
g->gray = o;
break;
}
case LUA_TTABLE: {
linktable(gco2t(o), &g->gray);
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 lu_mem traversetable (global_State *g, Table *h) {
const char *weakkey, *weakvalue;
const TValue *mode = gfasttm(g, h->metatable, TM_MODE);
markobject(g, h->metatable);
if (mode && ttisstring(mode) && /* is there a weak mode? */
((weakkey = strchr(svalue(mode), 'k')),
(weakvalue = strchr(svalue(mode), 'v')),
(weakkey || weakvalue))) { /* is really weak? */
black2gray(obj2gco(h)); /* keep table gray */
if (!weakkey) /* strong keys? */
traverseweakvalue(g, h);
else if (!weakvalue) /* strong values? */
traverseephemeron(g, h);
else /* all weak */
linktable(h, &g->allweak); /* nothing to traverse now */
}
else /* not weak */
traversestrongtable(g, h);
return sizeof(Table) + sizeof(TValue) * h->sizearray +
sizeof(Node) * cast(size_t, sizenode(h));
}
