/*
** 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 */
}
}
/* move `dead' udata that need finalization to list `tmudata' */
size_t luaC_separateudata (lua_State *L, int all) {
global_State *g = G(L);
size_t deadmem = 0;
GCObject **p = &g->mainthread->next;
GCObject *curr;
while ((curr = *p) != NULL) {
if (!(iswhite(curr) || all) || isfinalized(gco2u(curr)))
p = &curr->gch.next; /* don't bother with them */
else if (fasttm(L, gco2u(curr)->metatable, TM_GC) == NULL) {
markfinalized(gco2u(curr)); /* don't need finalization */
p = &curr->gch.next;
}
else { /* must call its gc method */
deadmem += sizeudata(gco2u(curr));
markfinalized(gco2u(curr));
*p = curr->gch.next;
/* link `curr' at the end of `tmudata' list */
if (g->tmudata == NULL) /* list is empty? */
g->tmudata = curr->gch.next = curr; /* creates a circular list */
else {
curr->gch.next = g->tmudata->gch.next;
g->tmudata->gch.next = curr;
g->tmudata = curr;
}
}
}
return deadmem;
}
/* move `dead' udata that need finalization to list `tmudata' */
size_t luaC_separateudata (lua_State *L) {
size_t deadmem = 0;
GCObject **p = &G(L)->rootudata;
GCObject *curr;
GCObject *collected = NULL; /* to collect udata with gc event */
GCObject **lastcollected = &collected;
while ((curr = *p) != NULL) {
lua_assert(curr->gch.tt == LUA_TUSERDATA);
if (ismarked(curr) || isfinalized(gcotou(curr)))
p = &curr->gch.next; /* don't bother with them */
else if (fasttm(L, gcotou(curr)->uv.metatable, TM_GC) == NULL) {
markfinalized(gcotou(curr)); /* don't need finalization */
p = &curr->gch.next;
}
else { /* must call its gc method */
deadmem += sizeudata(gcotou(curr)->uv.len);
*p = curr->gch.next;
curr->gch.next = NULL; /* link `curr' at the end of `collected' list */
*lastcollected = curr;
lastcollected = &curr->gch.next;
}
}
/* insert collected udata with gc event into `tmudata' list */
*lastcollected = G(L)->tmudata;
G(L)->tmudata = collected;
return deadmem;
}
/*
** The next function tells whether a key or value can be cleared from
** a weak table. Non-collectable objects are never removed from weak
** tables. Strings behave as `values', so are never removed too. for
** other objects: if really collected, cannot keep them; for userdata
** being finalized, keep them in keys, but not in values
*/
static int iscleared (const TValue *o, int iskey) {
if (!iscollectable(o)) return 0;
if (ttisstring(o)) {
stringmark(rawtsvalue(o)); /* strings are `values', so are never weak */
return 0;
}
return iswhite(gcvalue(o)) ||
(ttisuserdata(o) && (!iskey && isfinalized(uvalue(o))));
}
static GCObject *udata2finalize (global_State *g) {
GCObject *o = g->tobefnz; /* get first element */
lua_assert(isfinalized(o));
g->tobefnz = gch(o)->next; /* remove it from 'tobefnz' list */
gch(o)->next = g->allgc; /* return it to 'allgc' list */
g->allgc = o;
resetbit(gch(o)->marked, SEPARATED); /* mark that it is not in 'tobefnz' */
lua_assert(!isold(o)); /* see MOVE OLD rule */
if (!keepinvariantout(g)) /* not keeping invariant? */
makewhite(g, o); /* "sweep" object */
return 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 (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;
for (p = &g->allgc; *p != o; p = &gch(*p)->next) ;
*p = gch(o)->next; /* remove 'o' from root list */
gch(o)->next = g->finobj; /* link it in list 'finobj' */
g->finobj = o;
l_setbit(gch(o)->marked, SEPARATED); /* mark it as such */
resetoldbit(o); /* see MOVE OLD rule */
}
}
/*
** move all unreachable objects (or 'all' objects) that need
** finalization from list 'finobj' to list 'tobefnz' (to be finalized)
*/
static void separatetobefnz (lua_State *L, int all) {
global_State *g = G(L);
GCObject **p = &g->finobj;
GCObject *curr;
GCObject **lastnext = &g->tobefnz;
/* find last 'next' field in 'tobefnz' list (to add elements in its end) */
while (*lastnext != NULL)
lastnext = &gch(*lastnext)->next;
while ((curr = *p) != NULL) { /* traverse all finalizable objects */
lua_assert(!isfinalized(curr));
lua_assert(testbit(gch(curr)->marked, SEPARATED));
if (!(iswhite(curr) || all)) /* not being collected? */
p = &gch(curr)->next; /* don't bother with it */
else {
l_setbit(gch(curr)->marked, FINALIZEDBIT); /* won't be finalized again */
*p = gch(curr)->next; /* remove 'curr' from 'finobj' list */
gch(curr)->next = *lastnext; /* link at the end of 'tobefnz' list */
*lastnext = curr;
lastnext = &gch(curr)->next;
}
}
}
static void marktmu (GCState *st) {
GCObject *u;
#if LUA_REFCOUNT
for (u = st->g->tmudata_head.next; u != (GCObject*)&st->g->tmudata_tail; u = u->gch.next) {
#else !LUA_REFCOUNT
for (u = st->g->tmudata; u; u = u->gch.next) {
#endif LUA_REFCOUNT
unmark(u); /* may be marked, if left from previous GC */
reallymarkobject(st, u);
}
}
/* move `dead' udata that need finalization to list `tmudata' */
size_t luaC_separateudata (lua_State *L) {
size_t deadmem = 0;
#if LUA_REFCOUNT
GCObject **p = &G(L)->rootudata_head.next;
#else !LUA_REFCOUNT
GCObject **p = &G(L)->rootudata;
#endif LUA_REFCOUNT
GCObject *curr;
GCObject *collected = NULL; /* to collect udata with gc event */
#if !LUA_REFCOUNT
GCObject **lastcollected = &collected;
while ((curr = *p) != NULL) {
lua_assert(curr->gch.tt == LUA_TUSERDATA);
#else LUA_REFCOUNT
while ((curr = *p) != (GCObject*)&G(L)->rootudata_tail) {
#endif LUA_REFCOUNT
if (ismarked(curr) || isfinalized(gcotou(curr)))
p = &curr->gch.next; /* don't bother with them */
else if (fasttm(L, gcotou(curr)->uv.metatable, TM_GC) == NULL) {
markfinalized(gcotou(curr)); /* don't need finalization */
p = &curr->gch.next;
}
else { /* must call its gc method */
deadmem += sizeudata(gcotou(curr)->uv.len);
*p = curr->gch.next;
#if LUA_REFCOUNT
Unlink(curr);
curr->gch.next = (GCObject*)&G(L)->tmudata_tail; /* link `curr' at the end of `collected' list */
curr->gch.prev = G(L)->tmudata_tail.prev;
G(L)->tmudata_tail.prev->gch.next = curr;
G(L)->tmudata_tail.prev = curr;
#else !LUA_REFCOUNT
curr->gch.next = NULL; /* link `curr' at the end of `collected' list */
*lastcollected = curr;
lastcollected = &curr->gch.next;
#endif LUA_REFCOUNT
}
}
/* insert collected udata with gc event into `tmudata' list */
#if LUA_REFCOUNT
// *lastcollected = G(L)->tmudata_head.next;
// G(L)->tmudata_head.next = collected;
#else !LUA_REFCOUNT
*lastcollected = G(L)->tmudata;
G(L)->tmudata = collected;
#endif LUA_REFCOUNT
return deadmem;
}
static void removekey (lua_State *L, Node *n) {
(void)L;
setnilvalue(gval(n)); /* remove corresponding value ... */
if (iscollectable(gkey(n)))
setttype(gkey(n), LUA_TNONE); /* dead key; remove it */
}
