diff --git a/lvm.c b/lvm.c index 54ea6246..060321a5 100644 --- a/lvm.c +++ b/lvm.c @@ -1,5 +1,5 @@ /* -** $Id: lvm.c,v 2.264 2015/11/19 19:16:22 roberto Exp roberto $ +** $Id: lvm.c,v 2.265 2015/11/23 11:30:45 roberto Exp roberto $ ** Lua virtual machine ** See Copyright Notice in lua.h */ @@ -153,7 +153,7 @@ static int forlimit (const TValue *obj, lua_Integer *p, lua_Integer step, /* -** Complete a table access: if 't' is a table, 'tm' has its metamethod; +** Finish a table access: if 't' is a table, 'tm' has its metamethod; ** otherwise, 'tm' is NULL. */ void luaV_finishget (lua_State *L, const TValue *t, TValue *key, StkId val, @@ -176,32 +176,33 @@ void luaV_finishget (lua_State *L, const TValue *t, TValue *key, StkId val, } /* else repeat */ } - luaG_runerror(L, "gettable chain too long; possible loop"); + luaG_runerror(L, "'__index' chain too long; possible loop"); } /* -** Main function for table assignment (invoking metamethods if needed). -** Compute 't[key] = val' +** Finish a table assignment 't[key] = val'. +** If 'oldval' is NULL, 't' is not a table. Otherwise, 'oldval' points +** to the entry 't[key]', or to 'luaO_nilobject' if there is no such +** entry. (The value at 'oldval' must be nil, otherwise 'luaV_fastset' +** would have done the job.) */ void luaV_finishset (lua_State *L, const TValue *t, TValue *key, StkId val, const TValue *oldval) { int loop; /* counter to avoid infinite loops */ for (loop = 0; loop < MAXTAGLOOP; loop++) { - const TValue *tm; - if (oldval != NULL) { - lua_assert(ttistable(t) && ttisnil(oldval)); - /* must check the metamethod */ - if ((tm = fasttm(L, hvalue(t)->metatable, TM_NEWINDEX)) == NULL && - /* no metamethod; is there a previous entry in the table? */ - (oldval != luaO_nilobject || - /* no previous entry; must create one. (The next test is - always true; we only need the assignment.) */ - (oldval = luaH_newkey(L, hvalue(t), key), 1))) { + const TValue *tm; /* '__newindex' metamethod */ + if (oldval != NULL) { /* is 't' a table? */ + Table *h = hvalue(t); /* save 't' table */ + lua_assert(ttisnil(oldval)); /* old value must be nil */ + tm = fasttm(L, h->metatable, TM_NEWINDEX); /* get metamethod */ + if (tm == NULL) { /* no metamethod? */ + if (oldval == luaO_nilobject) /* no previous entry? */ + oldval = luaH_newkey(L, h, key); /* create one */ /* no metamethod and (now) there is an entry with given key */ - setobj2t(L, cast(TValue *, oldval), val); - invalidateTMcache(hvalue(t)); - luaC_barrierback(L, hvalue(t), val); + setobj2t(L, cast(TValue *, oldval), val); /* set its new value */ + invalidateTMcache(h); + luaC_barrierback(L, h, val); return; } /* else will try the metamethod */ @@ -220,7 +221,7 @@ void luaV_finishset (lua_State *L, const TValue *t, TValue *key, return; /* done */ /* else loop */ } - luaG_runerror(L, "settable chain too long; possible loop"); + luaG_runerror(L, "'__newindex' chain too long; possible loop"); } @@ -744,8 +745,8 @@ void luaV_finishOp (lua_State *L) { /* -** copy of 'luaV_gettable', but protecting call to potential metamethod -** (which can reallocate the stack) +** copy of 'luaV_gettable', but protecting the call to potential +** metamethod (which can reallocate the stack) */ #define gettableProtected(L,t,k,v) { const TValue *aux; \ if (luaV_fastget(L,t,k,aux,luaH_get)) { setobj2s(L, v, aux); } \