Improvements in 'luaL_traceback'
'luaL_traceback' changed to use an aux buffer instead of concats.
This should reduce the quantity of garbage it generates (in the
form of intermediate strings) while producing a trackback.
It also added information about the number of levels skipped when
skipping levels in a trace.
diff --git a/lauxlib.c b/lauxlib.c
index 89e53dc..d49ef57 100644
--- a/lauxlib.c
+++ b/lauxlib.c
@@ -46,8 +46,8 @@
/*
-** search for 'objidx' in table at index -1.
-** return 1 + string at top if find a good name.
+** Search for 'objidx' in table at index -1. ('objidx' must be an
+** absolute index.) Return 1 + string at top if it found a good name.
*/
static int findfield (lua_State *L, int objidx, int level) {
if (level == 0 || !lua_istable(L, -1))
@@ -60,10 +60,10 @@
return 1;
}
else if (findfield(L, objidx, level - 1)) { /* try recursively */
- lua_remove(L, -2); /* remove table (but keep name) */
- lua_pushliteral(L, ".");
- lua_insert(L, -2); /* place '.' between the two names */
- lua_concat(L, 3);
+ /* stack: lib_name, lib_table, field_name (top) */
+ lua_pushliteral(L, "."); /* place '.' between the two names */
+ lua_replace(L, -3); /* (in the slot ocupied by table) */
+ lua_concat(L, 3); /* lib_name.field_name */
return 1;
}
}
@@ -86,8 +86,8 @@
lua_pushstring(L, name + 3); /* push name without prefix */
lua_remove(L, -2); /* remove original name */
}
- lua_copy(L, -1, top + 1); /* move name to proper place */
- lua_pop(L, 2); /* remove pushed values */
+ lua_copy(L, -1, top + 1); /* copy name to proper place */
+ lua_settop(L, top + 1); /* remove table "loaded" an name copy */
return 1;
}
else {
@@ -130,32 +130,37 @@
LUALIB_API void luaL_traceback (lua_State *L, lua_State *L1,
const char *msg, int level) {
+ luaL_Buffer b;
lua_Debug ar;
- int top = lua_gettop(L);
int last = lastlevel(L1);
- int n1 = (last - level > LEVELS1 + LEVELS2) ? LEVELS1 : -1;
- if (msg)
- lua_pushfstring(L, "%s\n", msg);
- luaL_checkstack(L, 10, NULL);
- lua_pushliteral(L, "stack traceback:");
+ int limit2show = (last - level > LEVELS1 + LEVELS2) ? LEVELS1 : -1;
+ luaL_buffinit(L, &b);
+ if (msg) {
+ luaL_addstring(&b, msg);
+ luaL_addchar(&b, '\n');
+ }
+ luaL_addstring(&b, "stack traceback:");
while (lua_getstack(L1, level++, &ar)) {
- if (n1-- == 0) { /* too many levels? */
- lua_pushliteral(L, "\n\t..."); /* add a '...' */
- level = last - LEVELS2 + 1; /* and skip to last ones */
+ if (limit2show-- == 0) { /* too many levels? */
+ int n = last - level - LEVELS2 + 1; /* number of levels to skip */
+ lua_pushfstring(L, "\n\t...\t(skipping %d levels)", n);
+ luaL_addvalue(&b); /* add warning about skip */
+ level += n; /* and skip to last levels */
}
else {
lua_getinfo(L1, "Slnt", &ar);
- lua_pushfstring(L, "\n\t%s:", ar.short_src);
- if (ar.currentline > 0)
- lua_pushfstring(L, "%d:", ar.currentline);
- lua_pushliteral(L, " in ");
+ if (ar.currentline <= 0)
+ lua_pushfstring(L, "\n\t%s: in ", ar.short_src);
+ else
+ lua_pushfstring(L, "\n\t%s:%d: in ", ar.short_src, ar.currentline);
+ luaL_addvalue(&b);
pushfuncname(L, &ar);
+ luaL_addvalue(&b);
if (ar.istailcall)
- lua_pushliteral(L, "\n\t(...tail calls...)");
- lua_concat(L, lua_gettop(L) - top);
+ luaL_addstring(&b, "\n\t(...tail calls...)");
}
}
- lua_concat(L, lua_gettop(L) - top);
+ luaL_pushresult(&b);
}
/* }====================================================== */
