[Project] Settings: Add lua_settings library

1 files changed, 73 insertions, 0 deletions

diff --git a/lualib/lua_settings.lua b/lualib/lua_settings.lua
new file mode 100644
index 000000000..7f1679184
--- /dev/null
+++ b/lualib/lua_settings.lua
@@ -0,0 +1,73 @@
+--[[
+Copyright (c) 2019, Vsevolod Stakhov <vsevolod@highsecure.ru>
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+]]--
+
+--[[[
+-- @module lua_settings
+-- This module contains internal helpers for the settings infrastructure in Rspamd
+-- More details at https://rspamd.com/doc/configuration/settings.html
+--]]
+
+local exports = {}
+local known_ids = {}
+
+-- Returns numeric representation of the settings id
+local function numeric_settings_id(str)
+  local cr = require "rspamd_cryptobox_hash"
+  local util = require "rspamd_util"
+  local ret = util.unpack("I4",
+      cr.create_specific('xxh64'):update(str):bin())
+
+  return ret
+end
+
+local function register_settings_id(str, settings)
+  local numeric_id = numeric_settings_id(str)
+
+  if known_ids[numeric_id] then
+    -- Might be either rewrite or a collision
+    if known_ids[numeric_id].name ~= str then
+      local logger = require "rspamd_logger"
+
+      logger.errx(rspamd_config, 'settings ID clash! id %s maps to %s and conflicts with %s',
+          numeric_id, known_ids[numeric_id].name, str)
+
+      return nil
+    end
+  else
+    known_ids[numeric_id] = {
+      name = str,
+      settings = settings
+    }
+  end
+
+  return numeric_id
+end
+
+exports.register_settings_id = register_settings_id
+
+local function reset_ids()
+  known_ids = {}
+end
+
+exports.reset_ids = reset_ids
+
+local function settings_by_id(id)
+  return known_ids[id]
+end
+
+exports.settings_by_id = settings_by_id
+
+return exports
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