Auxiliary buffer cannot close box with 'lua_remove'
To remove a to-be-closed variable from the stack in the C API a
function must use 'lua_settop' or 'lua_pop'. Previous implementation of
'luaL_pushresult' was not closing the box. (This commit also added
tests to check that box is being closed "as soon as possible".)
diff --git a/lapi.c b/lapi.c
index da866a6..147ed0f 100644
--- a/lapi.c
+++ b/lapi.c
@@ -1213,8 +1213,8 @@
lua_lock(L);
o = index2stack(L, idx);
nresults = L->ci->nresults;
- api_check(L, L->openupval == NULL || uplevel(L->openupval) < o,
- "there is an already marked index below");
+ api_check(L, L->openupval == NULL || uplevel(L->openupval) <= o,
+ "marked index below or equal new one");
luaF_newtbcupval(L, o); /* create new to-be-closed upvalue */
if (!hastocloseCfunc(nresults)) /* function not marked yet? */
L->ci->nresults = codeNresults(nresults); /* mark it */
diff --git a/lauxlib.c b/lauxlib.c
index 6069ed1..fd4acbd 100644
--- a/lauxlib.c
+++ b/lauxlib.c
@@ -524,8 +524,8 @@
/*
** Returns a pointer to a free area with at least 'sz' bytes in buffer
-** 'B'. 'boxidx' is the position in the stack where the buffer's box is
-** or should be.
+** 'B'. 'boxidx' is the relative position in the stack where the
+** buffer's box is or should be.
*/
static char *prepbuffsize (luaL_Buffer *B, size_t sz, int boxidx) {
if (B->size - B->n >= sz) /* enough space? */
@@ -538,8 +538,10 @@
if (buffonstack(B)) /* buffer already has a box? */
newbuff = (char *)resizebox(L, boxidx, newsize); /* resize it */
else { /* no box yet */
+ lua_pushnil(L); /* reserve slot for final result */
newbox(L); /* create a new box */
- lua_insert(L, boxidx); /* move box to its intended position */
+ /* move box (and slot) to its intended position */
+ lua_rotate(L, boxidx - 1, 2);
lua_toclose(L, boxidx);
newbuff = (char *)resizebox(L, boxidx, newsize);
memcpy(newbuff, B->b, B->n * sizeof(char)); /* copy original content */
@@ -576,8 +578,8 @@
lua_State *L = B->L;
lua_pushlstring(L, B->b, B->n);
if (buffonstack(B)) {
- resizebox(L, -2, 0); /* delete old buffer */
- lua_remove(L, -2); /* remove its header from the stack */
+ lua_copy(L, -1, -3); /* move string to reserved slot */
+ lua_pop(L, 2); /* pop string and box (closing the box) */
}
}
diff --git a/testes/locals.lua b/testes/locals.lua
index 8766b3d..90a8b84 100644
--- a/testes/locals.lua
+++ b/testes/locals.lua
@@ -242,6 +242,7 @@
assert(a == 1 and b == 2 and c == 3 and X == 20 and Y == 10 and d == nil)
end
+
do -- errors in __close
local log = {}
local function foo (err)
@@ -264,7 +265,9 @@
and #log == 4)
end
+
if rawget(_G, "T") then
+
-- memory error inside closing function
local function foo ()
local *toclose y = function () T.alloccount() end
@@ -296,7 +299,7 @@
local function test ()
local *toclose x = enter(0) -- set a memory limit
-- creation of previous upvalue will raise a memory error
- os.exit(false) -- should not run
+ assert(false) -- should not run
end
local _, msg = pcall(test)
@@ -326,33 +329,54 @@
do -- testing 'toclose' in C string buffer
- local s = string.rep("a", 10000)
+ collectgarbage()
+ local s = string.rep('a', 10000) -- large string
+ local m = T.totalmem()
+ collectgarbage("stop")
+ s = string.upper(s) -- allocate buffer + new string (10K each)
+ -- ensure buffer was deallocated
+ assert(T.totalmem() - m <= 11000)
+ collectgarbage("restart")
+ end
+
+ do -- now some tests for freeing buffer in case of errors
+ local lim = 10000 -- some size larger than the static buffer
+ local extra = 2000 -- some extra memory (for callinfo, etc.)
+
+ local s = string.rep("a", lim)
+
+ -- concat this table needs two buffer resizes (one for each 's')
local a = {s, s}
- -- ensure proper initialization (stack space, metatable)
- table.concat(a)
- collectgarbage(); collectgarbage()
+ collectgarbage()
- local m = T.totalmem()
+ m = T.totalmem()
+ collectgarbage("stop")
+
+ -- error in the first buffer allocation
+ T. totalmem(m + extra)
+ assert(not pcall(table.concat, a))
+ -- first buffer was not even allocated
+ assert(T.totalmem() - m <= extra)
-- error in the second buffer allocation
- T.alloccount(3)
+ T. totalmem(m + lim + extra)
assert(not pcall(table.concat, a))
- T.alloccount()
-- first buffer was released by 'toclose'
- assert(T.totalmem() - m <= 5000)
+ assert(T.totalmem() - m <= extra)
-- error in creation of final string
- T.alloccount(4)
+ T.totalmem(m + 2 * lim + extra)
assert(not pcall(table.concat, a))
- T.alloccount()
-- second buffer was released by 'toclose'
- assert(T.totalmem() - m <= 5000)
+ assert(T.totalmem() - m <= extra)
- -- userdata, upvalue, buffer, buffer, string
- T.alloccount(5)
- assert(#table.concat(a) == 20000)
- T.alloccount()
+ -- userdata, upvalue, buffer, buffer, final string
+ T.totalmem(m + 4*lim + extra)
+ assert(#table.concat(a) == 2*lim)
+
+ T.totalmem(0) -- remove memory limit
+ collectgarbage("restart")
print'+'
end
