Prevent Lua from allocating all heap memory (Horus) (#4440)

* Fixes #4284: Prevent Lua from allocating all heap memory (Horus)
Lua bitmap functions cleanup and docs update
Added x or y < 0 check to drawBitmap()

* Proper float constant

radio/src/lua/interface.cpp

@@ -165,7 +165,7 @@ void luaClose(lua_State ** L)
     }
     else {
       // we can only disable Lua for the rest of the session
-      luaDisable();
+      if (*L == lsScripts) luaDisable();
     }
     UNPROTECT_LUA();
     *L = NULL;
@@ -954,6 +954,27 @@ bool luaTask(event_t evt, uint8_t scriptType, bool allowLcdUsage)
   return scriptWasRun;
 }
 
+void checkLuaMemoryUsage()
+{
+#if (LUA_MEM_MAX > 0)
+  uint32_t totalMemUsed = luaGetMemUsed(lsScripts);
+#if defined(COLORLCD)
+  totalMemUsed += luaGetMemUsed(lsWidgets);
+  totalMemUsed += luaExtraMemoryUsage;
+#endif
+  if (totalMemUsed > LUA_MEM_MAX) {
+    TRACE("checkLuaMemoryUsage(): max limit reached (%u), killing Lua", totalMemUsed);
+    // disable Lua scripts
+    luaClose(&lsScripts);
+    luaDisable();
+#if defined(COLORLCD)
+    // disable widgets
+    luaClose(&lsWidgets);
+#endif
+  }
+#endif
+}
+
 uint32_t luaGetMemUsed(lua_State * L)
 {
   return L ? (lua_gc(L, LUA_GCCOUNT, 0) << 10) + lua_gc(L, LUA_GCCOUNTB, 0) : 0;