libs: drop uvl and uvldoc
[project/luci.git] / libs / uvl / luasrc / uvl.lua
diff --git a/libs/uvl/luasrc/uvl.lua b/libs/uvl/luasrc/uvl.lua
deleted file mode 100644 (file)
index d2ea4bd..0000000
+++ /dev/null
@@ -1,1213 +0,0 @@
---[[
-
-UCI Validation Layer - Main Library
-(c) 2008 Jo-Philipp Wich <xm@leipzig.freifunk.net>
-(c) 2008 Steven Barth <steven@midlink.org>
-
-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
-
-$Id$
-
-]]--
-
-
---- UVL - UCI Validation Layer
--- @class      module
--- @cstyle     instance
-
-local fs = require "nixio.fs"
-local uci = require "luci.model.uci"
-local util = require "luci.util"
-local nutil = require "nixio.util"
-local table = require "table"
-local string = require "string"
-
-local require, pcall, ipairs, pairs = require, pcall, ipairs, pairs
-local type, error, tonumber, tostring = type, error, tonumber, tostring
-local unpack, loadfile, collectgarbage = unpack, loadfile, collectgarbage
-
-module "luci.uvl"
-
-local ERR = require "luci.uvl.errors".error
-local datatypes = require "luci.uvl.datatypes"
-local validation = require "luci.uvl.validation"
-local dependencies = require "luci.uvl.dependencies"
-
-local TYPE_SCHEME   = 0x00
-local TYPE_CONFIG   = 0x01
-local TYPE_SECTION  = 0x02
-local TYPE_OPTION   = 0x03
-local TYPE_ENUM     = 0x04
-
-local PAT_EXPR1                = "^%$?[%w_]+$"
-local PAT_EXPR2                = "^%$?[%w_]+%.%$?[%w_]+$"
-local PAT_EXPR3                = "^%$?[%w_]+%.%$?[%w_]+%.%$?[%w_]+$"
-
---- Boolean; default true;
--- treat sections found in config but not in scheme as error
-STRICT_UNKNOWN_SECTIONS    = true
-
---- Boolean; default true;
--- treat options found in config but not in scheme as error
-STRICT_UNKNOWN_OPTIONS     = true
-
---- Boolean; default true;
--- treat failed external validators as error
-STRICT_EXTERNAL_VALIDATORS = true
-
---- Boolean; default true;
--- treat list values stored as options like errors
-STRICT_LIST_TYPE           = true
-
-
-local default_schemedir = "/lib/uci/schema"
-local default_savedir = "/tmp/.uvl"
-
-
---- Object constructor
--- @class                      function
--- @name                       UVL
--- @param schemedir    Path to the scheme directory (optional)
--- @param configdir    Override config directory (optional)
--- @return                     Instance object
-UVL = util.class()
-
-function UVL.__init__( self, schemedir, configdir )
-       self.schemedir  = schemedir or default_schemedir
-       self.configdir  = configdir
-       self.packages   = { }
-       self.beenthere  = { }
-       self.depseen    = { }
-       self.uci                = uci
-       self.err                = ERR
-       self.dep                = dependencies
-       self.datatypes  = datatypes
-end
-
-
---- Parse given scheme and return the scheme tree.
--- @param scheme       Name of the scheme to parse
--- @return                     Table containing the parsed scheme or nil on error
--- @return                     String containing the reason for errors (if any)
-function UVL.get_scheme( self, scheme )
-       if not self.packages[scheme] then
-               local ok, err = self:read_scheme( scheme )
-               if not ok then
-                       return nil, err
-               end
-       end
-       return self.packages[scheme], nil
-end
-
---- Validate given configuration, section or option.
--- @param config       Name of the configuration to validate
--- @param section      Name of the section to validate (optional)
--- @param option       Name of the option to validate (optional)
--- @return                     Boolean indicating whether the given config validates
--- @return                     String containing the reason for errors (if any)
-function UVL.validate( self, config, section, option )
-       if config and section and option then
-               return self:validate_option( config, section, option )
-       elseif config and section then
-               return self:validate_section( config, section )
-       elseif config then
-               return self:validate_config( config )
-       end
-end
-
---- Validate given configuration.
--- @param cfg  Name of the configuration to validate
--- @return                     Boolean indicating whether the given config validates
--- @return                     String containing the reason for errors (if any)
-function UVL.validate_config( self, cfg, uci )
-
-       if not self.packages[cfg] then
-               local ok, err = self:read_scheme(cfg)
-               if not ok then
-                       return false, err
-               end
-       end
-
-       local co = config( self, uci or cfg, uci and cfg )
-       local sc = { }
-
-       self.beenthere = { }
-       self.depseen   = { }
-
-       if not co:config() then
-               return false, co:errors()
-       end
-
-       local function _uci_foreach( type, func )
-               for k, v in pairs(co:config()) do
-                       if v['.type'] == type then
-                               sc[type] = sc[type] + 1
-                               local ok, err = func( k, v )
-                               if not ok then co:error(err) end
-                       end
-               end
-       end
-
-       for k, v in pairs( self.packages[cfg].sections ) do
-               sc[k] = 0
-               _uci_foreach( k,
-                       function(s)
-                               return self:_validate_section( co:section(s) )
-                       end
-               )
-       end
-
-       if STRICT_UNKNOWN_SECTIONS then
-               for k, v in pairs(co:config()) do
-                       local so = co:section(k)
-                       if not self.beenthere[so:cid()] then
-                               co:error(ERR('SECT_UNKNOWN', so))
-                       end
-               end
-       end
-
-       for _, k in ipairs(util.keys(sc)) do
-               local so = co:section(k)
-               if so:scheme('required') and sc[k] == 0 then
-                       co:error(ERR('SECT_REQUIRED', so))
-               elseif so:scheme('unique') and sc[k] > 1 then
-                       co:error(ERR('SECT_UNIQUE', so))
-               end
-       end
-
-       return co:ok(), co:errors()
-end
-
---- Validate given config section.
--- @param config       Name of the configuration to validate
--- @param section      Name of the section to validate
--- @return                     Boolean indicating whether the given config validates
--- @return                     String containing the reason for errors (if any)
-function UVL.validate_section( self, cfg, section, uci )
-
-       if not self.packages[cfg] then
-               local ok, err = self:read_scheme( cfg )
-               if not ok then
-                       return false, err
-               end
-       end
-
-       local co = config( self, uci or cfg, uci and cfg )
-       local so = co:section( section )
-
-       self.beenthere = { }
-       self.depseen   = { }
-
-       if not co:config() then
-               return false, co:errors()
-       end
-
-       if so:config() then
-               return self:_validate_section( so )
-       else
-               return false, ERR('SECT_NOTFOUND', so)
-       end
-end
-
---- Validate given config option.
--- @param config       Name of the configuration to validate
--- @param section      Name of the section to validate
--- @param option       Name of the option to validate
--- @return                     Boolean indicating whether the given config validates
--- @return                     String containing the reason for errors (if any)
-function UVL.validate_option( self, cfg, section, option, uci )
-
-       if not self.packages[cfg] then
-               local ok, err = self:read_scheme( cfg )
-               if not ok then
-                       return false, err
-               end
-       end
-
-       local co = config( self, uci or cfg, uci and cfg )
-       local so = co:section( section )
-       local oo = so:option( option )
-
-       if not co:config() then
-               return false, co:errors()
-       end
-
-       if so:config() and oo:config() then
-               return self:_validate_option( oo )
-       else
-               return false, ERR('OPT_NOTFOUND', oo)
-       end
-end
-
-
-function UVL._validate_section( self, section )
-
-       self.beenthere[section:cid()] = true
-
-       if section:config() then
-               if section:scheme('named') == true and
-                  section:config('.anonymous') == true
-               then
-                       return false, ERR('SECT_NAMED', section)
-               end
-
-               for _, v in ipairs(section:variables()) do
-                       local ok, err = self:_validate_option( v )
-                       if not ok and (
-                               v:scheme('required') or v:scheme('type') == "enum" or (
-                                       not err:is('DEP_NOTEQUAL') and
-                                       not err:is('DEP_NOVALUE')
-                               )
-                       ) then
-                               section:error(err)
-                       end
-               end
-
-               local ok, err = dependencies.check( self, section )
-               if not ok then
-                       section:error(err)
-               end
-       else
-               return false, ERR('SECT_NOTFOUND', section)
-       end
-
-       if STRICT_UNKNOWN_OPTIONS and not section:scheme('dynamic') then
-               for k, v in pairs(section:config()) do
-                       local oo = section:option(k)
-                       if k:byte(1) == 46 and not self.beenthere[oo:cid()] then
-                               section:error(ERR('OPT_UNKNOWN', oo))
-                       end
-               end
-       end
-
-       return section:ok(), section:errors()
-end
-
-function UVL._validate_option( self, option, nodeps )
-
-       self.beenthere[option:cid()] = true
-
-       if not option:scheme() and not option:parent():scheme('dynamic') then
-               if STRICT_UNKNOWN_OPTIONS then
-                       return false, option:error(ERR('OPT_UNKNOWN', option))
-               else
-                       return true
-               end
-
-       elseif option:scheme() then
-               if not nodeps then
-                       local ok, err = dependencies.check( self, option )
-                       if not ok then
-                               if not err:is_all(
-                                       'OPT_REQUIRED',
-                                       'DEP_NOTEQUAL',
-                                       'DEP_NOVALUE'
-                               ) then
-                                       option:error(err)
-                                       return false, option:errors()
-                               else
-                                       return true
-                               end
-                       end
-               end
-
-               if option:scheme('required') and not option:value() then
-                       return false, option:error(ERR('OPT_REQUIRED', option))
-
-               elseif option:value() then
-                       local val = option:value()
-
-                       if option:scheme('type') == "reference" or
-                          option:scheme('type') == "enum"
-                       then
-                               local scheme_values = option:scheme('values') or { }
-                               local config_values = ( type(val) == "table" and val or { val } )
-                               for _, v in ipairs(config_values) do
-                                       if not scheme_values[v] then
-                                               return false, option:error( ERR(
-                                                       'OPT_BADVALUE',
-                                                       option, { v, util.serialize_data(
-                                                               util.keys(scheme_values)
-                                                       ) }
-                                               ) )
-                                       end
-                               end
-                       elseif option:scheme('type') == "list" then
-                               if type(val) ~= "table" and STRICT_LIST_TYPE then
-                                       return false, option:error(ERR('OPT_NOTLIST', option))
-                               end
-                       end
-
-                       if option:scheme('datatype') then
-                               local dt = option:scheme('datatype')
-
-                               if self.datatypes[dt] then
-                                       val = ( type(val) == "table" and val or { val } )
-                                       for i, v in ipairs(val) do
-                                               if not self.datatypes[dt]( v ) then
-                                                       return false, option:error(
-                                                               ERR('OPT_INVVALUE', option, { v, dt })
-                                                       )
-                                               end
-                                       end
-                               else
-                                       return false, option:error(ERR('OPT_DATATYPE', option, dt))
-                               end
-                       end
-
-                       val = ( type(val) == "table" and val or { val } )
-                       for _, v in ipairs(val) do
-                               if option:scheme('minlength') then
-                                       if #v < option:scheme('minlength') then
-                                               return false, option:error(ERR('OPT_RANGE', option))
-                                       end
-                               end
-
-                               if option:scheme('maxlength') then
-                                       if #v > option:scheme('maxlength') then
-                                               return false, option:error(ERR('OPT_RANGE', option))
-                                       end
-                               end
-
-                               local w = tonumber(v)
-
-                               if option:scheme('minimum') then
-                                       if not w or w < option:scheme('minimum') then
-                                               return false, option:error(ERR('OPT_RANGE', option))
-                                       end
-                               end
-
-                               if option:scheme('maximum') then
-                                       if not w or w > option:scheme('maximum') then
-                                               return false, option:error(ERR('OPT_RANGE', option))
-                                       end
-                               end
-                       end
-               end
-
-               local ok, err = validation.check( self, option )
-               if not ok and STRICT_EXTERNAL_VALIDATORS then
-                       return false, option:error(err)
-               end
-       end
-
-       return option:ok(), option:errors()
-end
-
---- Find all parts of given scheme and construct validation tree.
--- This is normally done on demand, so you don't have to call this function
--- by yourself.
--- @param shm  Name of the scheme to parse
--- @param alias                Create an alias for the loaded scheme
-function UVL.read_scheme( self, shm, alias )
-
-       local so = scheme( self, shm )
-       local bc = "%s/bytecode/%s.lua" %{ self.schemedir, shm }
-
-       if not fs.access(bc) then
-               local files = nutil.consume((fs.glob(self.schemedir .. '/*/' .. shm)))
-
-               if #files > 0 then
-                       local ok, err
-                       for _, file in ipairs(files) do
-                               if not fs.access(file) then
-                                       return false, so:error(ERR('SME_READ', so,file))
-                               end
-
-                               local uci = uci.cursor( fs.dirname(file), default_savedir )
-
-                               local sname = fs.basename(file)
-                               local sd, err = uci:load( sname )
-
-                               if not sd then
-                                       return false, ERR('UCILOAD', so, err)
-                               end
-
-                               ok, err = pcall(function()
-                                       uci:foreach(sname, "package", function(s)
-                                               self:_parse_package(so, s[".name"], s)
-                                       end)
-                                       uci:foreach(sname, "section", function(s)
-                                               self:_parse_section(so, s[".name"], s)
-                                       end)
-                                       uci:foreach(sname, "variable", function(s)
-                                               self:_parse_var(so, s[".name"], s)
-                                       end)
-                                       uci:foreach(sname, "enum", function(s)
-                                               self:_parse_enum(so, s[".name"], s)
-                                       end)
-
-                               end)
-                       end
-
-                       if ok and alias then self.packages[alias] = self.packages[shm] end
-                       return ok and self, err
-               else
-                       return false, so:error(ERR('SME_FIND', so, self.schemedir))
-               end
-       else
-               local sc = loadfile(bc)
-               if sc then
-                       self.packages[shm] = sc()
-                       return true
-               else
-                       return false, so:error(ERR('SME_READ',so,bc))
-               end
-       end
-end
-
--- helper function to check for required fields
-local function _req( t, n, c, r )
-       for i, v in ipairs(r) do
-               if not c[v] then
-                       local p, o = scheme:sid(), nil
-
-                       if t == TYPE_SECTION then
-                               o = section( scheme, nil, p, n )
-                       elseif t == TYPE_OPTION then
-                               o = option( scheme, nil, p, '(nil)', n )
-                       elseif t == TYPE_ENUM then
-                               o = enum( scheme, nil, p, '(nil)', '(nil)', n )
-                       end
-
-                       return false, ERR('SME_REQFLD',o,v)
-               end
-       end
-       return true
-end
-
--- helper function to validate references
-local function _ref( c, t )
-       local r, k, n = {}
-       if c == TYPE_SECTION then
-               k = "package"
-               n = 1
-       elseif c == TYPE_OPTION then
-               k = "section"
-               n = 2
-       elseif c == TYPE_ENUM then
-               k = "variable"
-               n = 3
-       end
-
-       for o in t[k]:gmatch("[^.]+") do
-               r[#r+1] = o
-       end
-       r[1] = ( #r[1] > 0 and r[1] or scheme:sid() )
-
-       if #r ~= n then
-               return false, ERR('SME_BADREF', scheme, k)
-       end
-
-       return r
-end
-
--- helper function to read bools
-local function _bool( v )
-       return ( v == "true" or v == "yes" or v == "on" or v == "1" )
-end
-
--- Step 0: get package meta information
-function UVL._parse_package(self, scheme, k, v)
-       local sid = scheme:sid()
-       local pkg = self.packages[sid] or {
-               ["name"]      = sid;
-               ["sections"]  = { };
-               ["variables"] = { };
-       }
-
-       pkg.title = v.title
-       pkg.description = v.description
-
-       self.packages[sid] = pkg
-end
-
--- Step 1: get all sections
-function UVL._parse_section(self, scheme, k, v)
-       local ok, err = _req( TYPE_SECTION, k, v, { "name", "package" } )
-       if err then error(scheme:error(err)) end
-
-       local r, err = _ref( TYPE_SECTION, v )
-       if err then error(scheme:error(err)) end
-
-       local p = self.packages[r[1]] or {
-               ["name"]      = r[1];
-               ["sections"]  = { };
-               ["variables"] = { };
-       }
-       p.sections[v.name]  = p.sections[v.name]  or { }
-       p.variables[v.name] = p.variables[v.name] or { }
-       self.packages[r[1]] = p
-
-       local s  = p.sections[v.name]
-       local so = scheme:section(v.name)
-
-       for k, v2 in pairs(v) do
-               if k ~= "name" and k ~= "package" and k:byte(1) == 46 then
-                       if k == "depends" then
-                               s.depends = self:_read_dependency( v2, s.depends )
-                               if not s.depends then
-                                       return false, scheme:error(
-                                               ERR('SME_BADDEP', so, util.serialize_data(s.depends))
-                                       )
-                               end
-                       elseif k == "dynamic" or k == "unique" or
-                              k == "required" or k == "named"
-                       then
-                               s[k] = _bool(v2)
-                       else
-                               s[k] = v2
-                       end
-               end
-       end
-
-       s.dynamic  = s.dynamic  or false
-       s.unique   = s.unique   or false
-       s.required = s.required or false
-       s.named    = s.named    or false
-end
-
--- Step 2: get all variables
-function UVL._parse_var(self, scheme, k, v)
-       local ok, err = _req( TYPE_OPTION, k, v, { "name", "section" } )
-       if err then error(scheme:error(err)) end
-
-       local r, err = _ref( TYPE_OPTION, v )
-       if err then error(scheme:error(err)) end
-
-       local p = self.packages[r[1]]
-       if not p then
-               error(scheme:error(
-                       ERR('SME_VBADPACK', {scheme:sid(), '', v.name}, r[1])
-               ))
-       end
-
-       local s = p.variables[r[2]]
-       if not s then
-               error(scheme:error(
-                       ERR('SME_VBADSECT', {scheme:sid(), '', v.name}, r[2])
-               ))
-       end
-
-       s[v.name] = s[v.name] or { }
-
-       local t  = s[v.name]
-       local so = scheme:section(r[2])
-       local to = so:option(v.name)
-
-       for k, v2 in pairs(v) do
-               if k ~= "name" and k ~= "section" and k:byte(1) == 46 then
-                       if k == "depends" then
-                               t.depends = self:_read_dependency( v2, t.depends )
-                               if not t.depends then
-                                       error(scheme:error(so:error(
-                                               ERR('SME_BADDEP', to, util.serialize_data(v2))
-                                       )))
-                               end
-                       elseif k == "validator" then
-                               t.validators = self:_read_validator( v2, t.validators )
-                               if not t.validators then
-                                       error(scheme:error(so:error(
-                                               ERR('SME_BADVAL', to, util.serialize_data(v2))
-                                       )))
-                               end
-                       elseif k == "valueof" then
-                               local values, err = self:_read_reference( v2 )
-                               if err then
-                                       error(scheme:error(so:error(
-                                               ERR('REFERENCE', to, util.serialize_data(v2)):child(err)
-                                       )))
-                               end
-                               t.type   = "reference"
-                               t.values = values
-                               t.valueof = type(v2) == "table" and v2 or {v2}
-                       elseif k == "required" then
-                               t[k] = _bool(v2)
-                       elseif k == "minlength" or k == "maxlength" or
-                   k == "minimum" or k == "maximum"
-            then
-                               t[k] = tonumber(v2)
-                       else
-                               t[k] = t[k] or v2
-                       end
-               end
-       end
-
-       t.type     = t.type     or "variable"
-       t.datatype = t.datatype or "string"
-       t.required = t.required or false
-end
-
--- Step 3: get all enums
-function UVL._parse_enum(self, scheme, k, v)
-       local ok, err = _req( TYPE_ENUM, k, v, { "value", "variable" } )
-       if err then error(scheme:error(err)) end
-
-       local r, err = _ref( TYPE_ENUM, v )
-       if err then error(scheme:error(err)) end
-
-       local p = self.packages[r[1]]
-       if not p then
-               error(scheme:error(
-                       ERR('SME_EBADPACK', {scheme:sid(), '', '', v.value}, r[1])
-               ))
-       end
-
-       local s = p.variables[r[2]]
-       if not s then
-               error(scheme:error(
-                       ERR('SME_EBADSECT', {scheme:sid(), '', '', v.value}, r[2])
-               ))
-       end
-
-       local t = s[r[3]]
-       if not t then
-               error(scheme:error(
-                       ERR('SME_EBADOPT', {scheme:sid(), '', '', v.value}, r[3])
-               ))
-       end
-
-
-       local so = scheme:section(r[2])
-       local oo = so:option(r[3])
-       local eo = oo:enum(v.value)
-
-       if t.type ~= "enum" and t.type ~= "reference" then
-               error(scheme:error(ERR('SME_EBADTYPE', eo)))
-       end
-
-       if not t.values then
-               t.values = { [v.value] = v.title or v.value }
-               t.valuelist = { {value = v.value, title = v.title} }
-       else
-               t.values[v.value] = v.title or v.value
-               t.valuelist[#t.valuelist + 1] = {value = v.value, title = v.title}
-       end
-
-       if not t.enum_depends then
-               t.enum_depends = { }
-       end
-
-       if v.default then
-               if t.default then
-                       error(scheme:error(ERR('SME_EBADDEF', eo)))
-               end
-               t.default = v.value
-       end
-
-       if v.depends then
-               t.enum_depends[v.value] = self:_read_dependency(
-                       v.depends, t.enum_depends[v.value]
-               )
-
-               if not t.enum_depends[v.value] then
-                       error(scheme:error(so:error(oo:error(
-                               ERR('SME_BADDEP', eo, util.serialize_data(v.depends))
-                       ))))
-               end
-       end
-end
-
--- Read a dependency specification
-function UVL._read_dependency( self, values, deps )
-       local expr = "%$?[%w_]+"
-       if values then
-               values = ( type(values) == "table" and values or { values } )
-               for _, value in ipairs(values) do
-                       local condition = { }
-                       for val in value:gmatch("[^,]+") do
-                               local k, e, v = val:match("%s*([%w$_.]+)%s*(=?)%s*(.*)")
-
-                               if k and (
-                                       k:match(PAT_EXPR1) or k:match(PAT_EXPR2) or k:match(PAT_EXPR3)
-                               ) then
-                                       condition[k] = (e == '=') and v or true
-                               else
-                                       return nil
-                               end
-                       end
-
-                       if not deps then
-                               deps = { condition }
-                       else
-                               deps[#deps+1] = condition
-                       end
-               end
-       end
-
-       return deps
-end
-
--- Read a validator specification
-function UVL._read_validator( self, values, validators )
-       if values then
-               values = ( type(values) == "table" and values or { values } )
-               for _, value in ipairs(values) do
-                       local validator
-
-                       if value:match("^exec:") then
-                               validator = value:gsub("^exec:","")
-                       elseif value:match("^lua:") then
-                               validator = self:_resolve_function( (value:gsub("^lua:","") ) )
-                       elseif value:match("^regexp:") then
-                               local pattern = value:gsub("^regexp:","")
-                               validator = function( type, dtype, pack, sect, optn, arg1, arg2, arg3, arg4, arg5 )
-                                       local values = { arg1, arg2, arg3, arg4, arg5 }
-                                       for _, v in ipairs(values) do
-                                               local ok, match =
-                                                       pcall( string.match, v, pattern )
-
-                                               if not ok then
-                                                       return false, match
-                                               elseif not match then
-                                                       return false,
-                                                               'Value "%s" does not match pattern "%s"' % {
-                                                                       v, pattern
-                                                               }
-                                               end
-                                       end
-                                       return true
-                               end
-                       end
-
-                       if validator then
-                               if not validators then
-                                       validators = { validator }
-                               else
-                                       validators[#validators+1] = validator
-                               end
-                       else
-                               return nil
-                       end
-               end
-
-               return validators
-       end
-end
-
--- Read a reference specification (XXX: We should validate external configs too...)
-function UVL._read_reference( self, values )
-       local val = { }
-       values = ( type(values) == "table" and values or { values } )
-
-       for _, value in ipairs(values) do
-               local ref = util.split(value, ".")
-
-               if #ref == 2 or #ref == 3 then
-                       local co = config( self, ref[1] )
-                       if not co:config() then return false, co:errors() end
-
-                       for k, v in pairs(co:config()) do
-                               if v['.type'] == ref[2] then
-                                       if #ref == 2 then
-                                               if v['.anonymous'] == true then
-                                                       return false, ERR('SME_INVREF', '', value)
-                                               end
-                                               val[k] = k      -- XXX: title/description would be nice
-                                       elseif v[ref[3]] then
-                                               val[v[ref[3]]] = v[ref[3]]  -- XXX: dito
-                                       end
-                               end
-                       end
-               else
-                       return false, ERR('SME_BADREF', '', value)
-               end
-       end
-
-       return val, nil
-end
-
--- Resolve given path
-function UVL._resolve_function( self, value )
-       local path = util.split(value, ".")
-
-       for i=1, #path-1 do
-               local stat, mod = pcall(
-                       require, table.concat(path, ".", 1, i)
-               )
-
-               if stat and mod then
-                       for j=i+1, #path-1 do
-                               if not type(mod) == "table" then
-                                       break
-                               end
-                               mod = mod[path[j]]
-                               if not mod then
-                                       break
-                               end
-                       end
-                       mod = type(mod) == "table" and mod[path[#path]] or nil
-                       if type(mod) == "function" then
-                               return mod
-                       end
-               end
-       end
-end
-
-
---- Object representation of an uvl item - base class.
-uvlitem = util.class()
-
-function uvlitem.cid(self)
-       if #self.cref == 1 then
-               return self.cref[1]
-       else
-               local r = { unpack(self.cref) }
-               local c = self.c
-               if c and c[r[2]] and c[r[2]]['.anonymous'] and c[r[2]]['.index'] then
-                       r[2] = '@' .. c[r[2]]['.type'] ..
-                                  '[' .. tostring(c[r[2]]['.index']) .. ']'
-               end
-               return table.concat( r, '.' )
-       end
-end
-
-function uvlitem.sid(self)
-       return table.concat( self.sref, '.' )
-end
-
-function uvlitem.scheme(self, opt)
-       local s = self.s and self.s.packages
-       s = s      and s[self.sref[1]]
-       if #self.sref == 4 or #self.sref == 3 then
-               s = s      and s.variables
-               s = s      and s[self.sref[2]]
-               s = s      and s[self.sref[3]]
-       elseif #self.sref == 2 then
-               s = s      and s.sections
-               s = s      and s[self.sref[2]]
-       end
-
-       if s and opt then
-               return s[opt]
-       elseif s then
-               return s
-       end
-end
-
-function uvlitem.config(self, opt)
-       local c = self.c
-
-       if #self.cref >= 2 and #self.cref <= 4 then
-               c = c and self.c[self.cref[2]] or nil
-               if #self.cref >= 3 then
-                       c = c and c[self.cref[3]] or nil
-               end
-       end
-
-       if c and opt then
-               return c[opt]
-       elseif c then
-               return c
-       end
-end
-
-function uvlitem.title(self)
-       return self:scheme() and self:scheme('title') or
-               self.cref[3] or self.cref[2] or self.cref[1]
-end
-
-function uvlitem.type(self)
-       if self.t == TYPE_CONFIG then
-               return 'config'
-       elseif self.t == TYPE_SECTION then
-               return 'section'
-       elseif self.t == TYPE_OPTION then
-               return 'option'
-       elseif self.t == TYPE_ENUM then
-               return 'enum'
-       end
-end
-
-function uvlitem.error(self, arg1, arg2, arg3, arg4, arg5)
-       if not self.e then
-               local errconst = { 'CONFIG', 'SECTION', 'OPTION', 'OPTION' }
-               self.e = ERR( errconst[#self.cref], self )
-       end
-
-       return self.e:child( arg1, arg2, arg3, arg4, arg5 )
-end
-
-function uvlitem.errors(self)
-       return self.e
-end
-
-function uvlitem.ok(self)
-       return not self:errors()
-end
-
-function uvlitem.parent(self)
-       if self.p then
-               return self.p
-       elseif #self.cref == 3 or #self.cref == 4 then
-               return section( self.s, self.c, self.cref[1], self.cref[2] )
-       elseif #self.cref == 2 then
-               return config( self.s, self.c, self.cref[1] )
-       else
-               return nil
-       end
-end
-
-function uvlitem._loadconf(self, co, c, configdir)
-       co = co or self._configcache
-       if not co then
-               local err
-               co, err = uci.cursor(configdir):get_all(c)
-
-               if err then
-                       self:error(ERR('UCILOAD', self, err))
-               end
-
-               self._configcache = co
-       end
-       return co
-end
-
-
---- Object representation of a scheme.
--- @class      scheme
--- @cstyle     instance
--- @name       luci.uvl.scheme
-
---- Scheme instance constructor.
--- @class                      function
--- @name                       scheme
--- @param scheme       Scheme instance
--- @param co           Configuration data
--- @param c                    Configuration name
--- @return                     Config instance
-scheme = util.class(uvlitem)
-
-function scheme.__init__(self, scheme, co, c)
-       if not c then
-               c, co = co, nil
-       end
-
-       self.cref = { c }
-       self.sref = { c }
-       self.c    = self:_loadconf(co, c, scheme.configdir)
-       self.s    = scheme
-       self.t    = TYPE_SCHEME
-end
-
---- Add an error to scheme.
--- @return     Scheme error context
-function scheme.error(self, arg1, arg2, arg3, arg4, arg5)
-       if not self.e then self.e = ERR( 'SCHEME', self ) end
-       return self.e:child( arg1, arg2, arg3, arg4, arg5 )
-end
-
---- Get an associated config object.
--- @return     Config instance
-function scheme.config(self)
-       local co = config( self.s, self.cref[1] )
-             co.p = self
-
-       return co
-end
-
---- Get all section objects associated with this scheme.
--- @return     Table containing all associated luci.uvl.section instances
-function scheme.sections(self)
-       local v = { }
-       if self.s.packages[self.sref[1]].sections then
-               for o, _ in pairs( self.s.packages[self.sref[1]].sections ) do
-                       v[#v+1] = option(
-                               self.s, self.c, self.cref[1], self.cref[2], o
-                       )
-               end
-       end
-       return v
-end
-
---- Get an associated section object.
--- @param s    Section to select
--- @return     Section instance
-function scheme.section(self, s)
-       local so = section( self.s, self.c, self.cref[1], s )
-             so.p = self
-
-       return so
-end
-
-
---- Object representation of a config.
--- @class      config
--- @cstyle     instance
--- @name       luci.uvl.config
-
---- Config instance constructor.
--- @class                      function
--- @name                       config
--- @param scheme       Scheme instance
--- @param co           Configuration data
--- @param c                    Configuration name
--- @return                     Config instance
-config = util.class(uvlitem)
-
-function config.__init__(self, scheme, co, c)
-       if not c then
-               c, co = co, nil
-       end
-       self.cref = { c }
-       self.sref = { c }
-       self.c    = self:_loadconf(co, c, scheme.configdir)
-       self.s    = scheme
-       self.t    = TYPE_CONFIG
-end
-
---- Get all section objects associated with this config.
--- @return     Table containing all associated luci.uvl.section instances
-function config.sections(self)
-       local v = { }
-       if self.s.packages[self.sref[1]].sections then
-               for o, _ in pairs( self.s.packages[self.sref[1]].sections ) do
-                       v[#v+1] = option(
-                               self.s, self.c, self.cref[1], self.cref[2], o
-                       )
-               end
-       end
-       return v
-end
-
---- Get an associated section object.
--- @param s    Section to select
--- @return     Section instance
-function config.section(self, s)
-       local so = section( self.s, self.c, self.cref[1], s )
-             so.p = self
-
-       return so
-end
-
-
---- Object representation of a scheme/config section.
--- @class      module
--- @cstyle     instance
--- @name       luci.uvl.section
-
---- Section instance constructor.
--- @class                      function
--- @name                       section
--- @param scheme       Scheme instance
--- @param co           Configuration data
--- @param c                    Configuration name
--- @param s                    Section name
--- @return                     Section instance
-section = util.class(uvlitem)
-
-function section.__init__(self, scheme, co, c, s)
-       self.cref = { c, s }
-       self.sref = { c, co and co[s] and co[s]['.type'] or s }
-       self.c    = self:_loadconf(co, c, scheme.configdir)
-       self.s    = scheme
-       self.t    = TYPE_SECTION
-end
-
---- Get all option objects associated with this section.
--- @return     Table containing all associated luci.uvl.option instances
-function section.variables(self)
-       local v = { }
-       if self.s.packages[self.sref[1]].variables[self.sref[2]] then
-               for o, _ in pairs(
-                       self.s.packages[self.sref[1]].variables[self.sref[2]]
-               ) do
-                       v[#v+1] = option(
-                               self.s, self.c, self.cref[1], self.cref[2], o
-                       )
-               end
-       end
-       return v
-end
-
---- Get an associated option object.
--- @param o    Option to select
--- @return     Option instance
-function section.option(self, o)
-       local oo = option( self.s, self.c, self.cref[1], self.cref[2], o )
-             oo.p = self
-
-       return oo
-end
-
-
---- Object representation of a scheme/config option.
--- @class      module
--- @cstyle     instance
--- @name       luci.uvl.option
-
---- Section instance constructor.
--- @class                      function
--- @name                       option
--- @param scheme       Scheme instance
--- @param co           Configuration data
--- @param c                    Configuration name
--- @param s                    Section name
--- @param o                    Option name
--- @return                     Option instance
-option = util.class(uvlitem)
-
-function option.__init__(self, scheme, co, c, s, o)
-       self.cref = { c, s, o }
-       self.sref = { c, co and co[s] and co[s]['.type'] or s, o }
-       self.c    = self:_loadconf(co, c, scheme.configdir)
-       self.s    = scheme
-       self.t    = TYPE_OPTION
-end
-
---- Get the value of this option.
--- @return     The associated configuration value
-function option.value(self)
-       local v = self:config() or self:scheme('default')
-       if v and self:scheme('multival') then
-               v = util.split( v, "%s+", nil, true )
-       end
-       return v
-end
-
---- Get the associated section information in scheme.
--- @return     Table containing the scheme properties
-function option.section(self)
-       return self.s.packages[self.sref[1]].sections[self.sref[2]]
-end
-
---- Construct an enum object instance from given or default value.
--- @param v    Value to select
--- @return     Enum instance for selected value
-function option.enum(self, val)
-       return enum(
-               self.s, self.c,
-               self.cref[1], self.cref[2], self.cref[3],
-               val or self:value()
-       )
-end
-
-
---- Object representation of a enum value.
--- @class      module
--- @cstyle     instance
--- @name       luci.uvl.enum
-
---- Section instance constructor.
--- @class                      function
--- @name                       enum
--- @param scheme       Scheme instance
--- @param co           Configuration data
--- @param c                    Configuration name
--- @param s                    Section name
--- @param o                    Enum name
--- @param v                    Enum value
--- @return                     Enum value instance
-enum = util.class(option)
-
-function enum.__init__(self, scheme, co, c, s, o, v)
-       self.cref = { c, s, o, v }
-       self.sref = { c, co and co[s] and co[s]['.type'] or s, o, v }
-       self.c    = self:_loadconf(co, c, scheme.configdir)
-       self.s    = scheme
-       self.t    = TYPE_ENUM
-end