Function loadModule

pj_scripting/src/luau_engine.cpp:333–362

Compile + load `source` and run its main chunk, leaving the returned module value on top of `L`. Returns an error string (empty on success).

// Compile + load `source` and run its main chunk, leaving the returned module
// value on top of `L`. Returns an error string (empty on success).
std::string loadModule(lua_State* L, BudgetState* budget, const std::string& source) {
  if (source.size() > kMaxSourceBytes) {  // luau_compile runs on the host heap, outside the VM cap
    return "filter source exceeds the size limit";
  }
  lua_CompileOptions opts = {};
  opts.optimizationLevel = 1;
  opts.debugLevel = 1;  // line info for error messages
  std::size_t bc_size = 0;
  char* bc = luau_compile(source.c_str(), source.size(), &opts, &bc_size);
  if (bc == nullptr) {
    return "luau_compile failed";
  }
  const int load_status = luau_load(L, "=filter", bc, bc_size, 0);
  std::free(bc);
  if (load_status != 0) {
    std::string err = lua_isstring(L, -1) ? lua_tostring(L, -1) : "luau_load failed";
    lua_pop(L, 1);
    return err;
  }
  if (lua_pcall(L, 0, 1, 0) != 0) {
    std::string err = lua_isstring(L, -1) ? lua_tostring(L, -1) : "module evaluation failed";
    lua_pop(L, 1);
    return err;
  }
  if (budget->tripped) {  // a top-level pcall may have swallowed the watchdog error
    lua_pop(L, 1);
    return "filter module exceeded its instruction budget during evaluation";
  }
  return {};
}

// Read metadata (NOT create) from the class table on top of `L` into a
// FilterClass. Leaves the stack as found. Returns an error string.