nik/lush
1
1
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

To-be-closed variables must be closed on initialization

Browse Source 
When initializing a to-be-closed variable, check whether it has a
'__close' metamethod (or is a false value) and raise an error if
if it hasn't. This produces more accurate error messages. (The
check before closing still need to be done: in the C API, the value
is not constant; and the object may lose its '__close' metamethod
during the block.)
This commit is contained in:
Roberto Ierusalimschy
2019-07-31 10:43:51 -03:00
parent 35b4efc270
commit f645d31573
6 changed files with 70 additions and 41 deletions
Download Patch File Download Diff File Expand all files Collapse all files

49
lfunc.c
View File

@@ -123,12 +123,24 @@ static int prepclosingmethod (lua_State *L, TValue *obj, TValue *err) {
}
/*
** Raise an error with message 'msg', inserting the name of the
** local variable at position 'level' in the stack.
*/
static void varerror (lua_State *L, StkId level, const char *msg) {
int idx = cast_int(level - L->ci->func);
const char *vname = luaG_findlocal(L, L->ci, idx, NULL);
if (vname == NULL) vname = "?";
luaG_runerror(L, msg, vname);
}
/*
** Prepare and call a closing method. If status is OK, code is still
** inside the original protected call, and so any error will be handled
** there. Otherwise, a previous error already activated original
** there. Otherwise, a previous error already activated the original
** protected call, and so the call to the closing method must be
** protected here. (A status = CLOSEPROTECT behaves like a previous
** protected here. (A status == CLOSEPROTECT behaves like a previous
** error, to also run the closing method in protected mode).
** If status is OK, the call to the closing method will be pushed
** at the top of the stack. Otherwise, values are pushed after
@@ -140,12 +152,8 @@ static int callclosemth (lua_State *L, StkId level, int status) {
if (likely(status == LUA_OK)) {
if (prepclosingmethod(L, uv, &G(L)->nilvalue)) /* something to call? */
callclose(L, NULL); /* call closing method */
else if (!ttisnil(uv)) { /* non-closable non-nil value? */
int idx = cast_int(level - L->ci->func);
const char *vname = luaG_findlocal(L, L->ci, idx, NULL);
if (vname == NULL) vname = "?";
luaG_runerror(L, "attempt to close non-closable variable '%s'", vname);
}
else if (!l_isfalse(uv)) /* non-closable non-false value? */
varerror(L, level, "attempt to close non-closable variable '%s'");
}
else { /* must close the object in protected mode */
ptrdiff_t oldtop;
@@ -170,9 +178,7 @@ static int callclosemth (lua_State *L, StkId level, int status) {
** (can raise a memory-allocation error)
*/
static void trynewtbcupval (lua_State *L, void *ud) {
StkId level = cast(StkId, ud);
lua_assert(L->openupval == NULL || uplevel(L->openupval) < level);
newupval(L, 1, level, &L->openupval);
newupval(L, 1, cast(StkId, ud), &L->openupval);
}
@@ -182,13 +188,22 @@ static void trynewtbcupval (lua_State *L, void *ud) {
** as there is no upvalue to call it later.
*/
void luaF_newtbcupval (lua_State *L, StkId level) {
int status = luaD_rawrunprotected(L, trynewtbcupval, level);
if (unlikely(status != LUA_OK)) { /* memory error creating upvalue? */
lua_assert(status == LUA_ERRMEM);
luaD_seterrorobj(L, LUA_ERRMEM, level + 1); /* save error message */
if (prepclosingmethod(L, s2v(level), s2v(level + 1)))
TValue *obj = s2v(level);
lua_assert(L->openupval == NULL || uplevel(L->openupval) < level);
if (!l_isfalse(obj)) { /* false doesn't need to be closed */
int status;
const TValue *tm = luaT_gettmbyobj(L, obj, TM_CLOSE);
if (ttisnil(tm)) /* no metamethod? */
varerror(L, level, "variable '%s' got a non-closable value");
status = luaD_rawrunprotected(L, trynewtbcupval, level);
if (unlikely(status != LUA_OK)) { /* memory error creating upvalue? */
lua_assert(status == LUA_ERRMEM);
luaD_seterrorobj(L, LUA_ERRMEM, level + 1); /* save error message */
/* next call must succeed, as object is closable */
prepclosingmethod(L, s2v(level), s2v(level + 1));
callclose(L, NULL); /* call closing method */
luaD_throw(L, LUA_ERRMEM); /* throw memory error */
luaD_throw(L, LUA_ERRMEM); /* throw memory error */
}
}
}