-- mod_storage_gdbm

-- Copyright (C) 2014 Kim Alvefur

--

-- This file is MIT/X11 licensed.

-- 

-- Depends on lgdbm:

-- http://webserver2.tecgraf.puc-rio.br/~lhf/ftp/lua/#lgdbm

local gdbm = require"gdbm";

local path = require"util.paths";

local lfs = require"lfs";

local serialize, deserialize = import("util.serialization", "serialize", "deserialize");

local base_path = path.resolve_relative_path(prosody.paths.data, module.host);

lfs.mkdir(base_path);

local cache = {};

local driver = {};

local driver_mt = { __index = driver };

function driver:set(user, value)

	local ok, err = gdbm.replace(self._db, user or "@", serialize(value));

	if not ok then return nil, err; end

	return true;

end

function driver:get(user)

	local data, err = gdbm.fetch(self._db, user or "@");

	if not data then return nil, err; end

	return deserialize(data);

end

function open(_, store, typ)

	typ = typ or "keyval";

	if typ ~= "keyval" then

		return nil, "unsupported-store";

	end

	local db_path = path.join(base_path, store) .. ".db";

	local db = cache[db_path];

	if not db then

		db = assert(gdbm.open(db_path, "c"));

		cache[db_path] = db;

	end

	return setmetatable({ _db = db; _path = db_path; store = store, typ = type }, driver_mt);

end

function module.unload()

	for path, db in pairs(cache) do

		gdbm.sync(db);

		gdbm.close(db);

	end

end

module:provides"storage";