Function RedisRegisterFunction

src/storage/scripting.cc:231–295

}

int RedisRegisterFunction(lua_State *lua) {
  int argc = lua_gettop(lua);

  if (argc < 2 || argc > 3) {
    lua_pushstring(lua, "wrong number of arguments to redis.register_function().");
    return lua_error(lua);
  }

  lua_getglobal(lua, REDIS_FUNCTION_LIBNAME);
  if (lua_isnil(lua, -1)) {
    lua_pop(lua, 1);
    lua_pushstring(lua, "redis.register_function() need to be called from FUNCTION LOAD.");
    return lua_error(lua);
  }

  std::string libname = lua_tostring(lua, -1);
  lua_pop(lua, 1);

  // set this function to global
  std::string name = lua_tostring(lua, 1);
  if (argc == 3) {
    auto flags = ExtractFlagsFromRegisterFunction(lua);
    if (!flags) {
      lua_pushstring(lua, flags.Msg().c_str());
      return lua_error(lua);
    }
    lua_pushinteger(lua, static_cast<lua_Integer>(flags.GetValue()));
    lua_setglobal(lua, (REDIS_LUA_REGISTER_FUNC_FLAGS_PREFIX + name).c_str());
  }
  lua_setglobal(lua, (REDIS_LUA_REGISTER_FUNC_PREFIX + name).c_str());

  // set this function name to REDIS_FUNCTION_LIBRARIES[libname]
  lua_getglobal(lua, REDIS_FUNCTION_LIBRARIES);
  if (lua_isnil(lua, -1)) {
    lua_pop(lua, 1);
    lua_newtable(lua);
  }
  lua_getfield(lua, -1, libname.c_str());
  if (lua_isnil(lua, -1)) {
    lua_pop(lua, 1);
    lua_newtable(lua);
  }
  size_t len = lua_objlen(lua, -1);
  lua_pushstring(lua, name.c_str());
  lua_rawseti(lua, -2, static_cast<int>(len) + 1);
  lua_setfield(lua, -2, libname.c_str());
  lua_setglobal(lua, REDIS_FUNCTION_LIBRARIES);

  // check if it needs to store
  lua_getglobal(lua, REDIS_FUNCTION_NEEDSTORE);
  if (!lua_toboolean(lua, -1)) {
    return 0;
  }

  // store the map from function name to library name
  auto *script_run_ctx = GetFromRegistry<ScriptRunCtx>(lua, REGISTRY_SCRIPT_RUN_CTX_NAME);
  CHECK(script_run_ctx != nullptr);