Test fix for #7787 (Map Editor crashes after pressing "Stop Testing")

Author: ccw808

src/lapi.c

@@ -106,6 +106,16 @@ LUA_API int lua_checkstack (lua_State *L, int size) {
   return res;
 }
 
+// MTA addition - Return stack space
+LUA_API int lua_getstackgap (lua_State *L) {
+  int res, gap1, gap2; 
+  lua_lock(L);
+  gap1 = ( (char *)L->stack_last - (char *)L->top ) / (int)sizeof(TValue);
+  gap2 = L->ci->top - L->top;
+  res = gap1 < gap2 ? gap1 : gap2;
+  lua_unlock(L);
+  return res;
+}
 
 LUA_API void lua_xmove (lua_State *from, lua_State *to, int n) {
   int i;

src/lua.h

@@ -91,7 +91,7 @@ typedef void * (*lua_Alloc) (void *ud, void *ptr, size_t osize, size_t nsize);
 
 
 /* minimum Lua stack available to a C function */
-#define LUA_MINSTACK	20
+#define LUA_MINSTACK	40     // MTA change. Was 20
 
 
 /*
@@ -134,6 +134,7 @@ LUA_API void  (lua_remove) (lua_State *L, int idx);
 LUA_API void  (lua_insert) (lua_State *L, int idx);
 LUA_API void  (lua_replace) (lua_State *L, int idx);
 LUA_API int   (lua_checkstack) (lua_State *L, int sz);
+LUA_API int   (lua_getstackgap) (lua_State *L);         // MTA addition
 
 LUA_API void  (lua_xmove) (lua_State *from, lua_State *to, int n);
 

src/lua5.1.def

@@ -19,6 +19,7 @@ EXPORTS
   lua_lessthan
   lua_rawequal
   lua_checkstack
+  lua_getstackgap
   lua_cpcall
   lua_error
   lua_getmetatable