libs/web: introduce recursive expression support for datatypes, introduce "or" and...

[project/luci.git] / libs / web / luasrc / cbi.lua

--[[
LuCI - Configuration Bind Interface

Description:
Offers an interface for binding configuration values to certain
data types. Supports value and range validation and basic dependencies.

FileId:
$Id$

License:
Copyright 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

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("luci.cbi", package.seeall)

require("luci.template")
local util = require("luci.util")
require("luci.http")


--local event      = require "luci.sys.event"
local fs         = require("nixio.fs")
local uci        = require("luci.model.uci")
local datatypes  = require("luci.cbi.datatypes")
local class      = util.class
local instanceof = util.instanceof

FORM_NODATA  =  0
FORM_PROCEED =  0
FORM_VALID   =  1
FORM_DONE        =  1
FORM_INVALID = -1
FORM_CHANGED =  2
FORM_SKIP    =  4

AUTO = true

CREATE_PREFIX = "cbi.cts."
REMOVE_PREFIX = "cbi.rts."
RESORT_PREFIX = "cbi.sts."
FEXIST_PREFIX = "cbi.cbe."

-- Loads a CBI map from given file, creating an environment and returns it
function load(cbimap, ...)
        local fs   = require "nixio.fs"
        local i18n = require "luci.i18n"
        require("luci.config")
        require("luci.util")

        local upldir = "/lib/uci/upload/"
        local cbidir = luci.util.libpath() .. "/model/cbi/"
        local func, err

        if fs.access(cbidir..cbimap..".lua") then
                func, err = loadfile(cbidir..cbimap..".lua")
        elseif fs.access(cbimap) then
                func, err = loadfile(cbimap)
        else
                func, err = nil, "Model '" .. cbimap .. "' not found!"
        end

        assert(func, err)

        luci.i18n.loadc("base")

        local env = {
                translate=i18n.translate,
                translatef=i18n.translatef,
                arg={...}
        }

        setfenv(func, setmetatable(env, {__index =
                function(tbl, key)
                        return rawget(tbl, key) or _M[key] or _G[key]
                end}))

        local maps       = { func() }
        local uploads    = { }
        local has_upload = false

        for i, map in ipairs(maps) do
                if not instanceof(map, Node) then
                        error("CBI map returns no valid map object!")
                        return nil
                else
                        map:prepare()
                        if map.upload_fields then
                                has_upload = true
                                for _, field in ipairs(map.upload_fields) do
                                        uploads[
                                                field.config .. '.' ..
                                                (field.section.sectiontype or '1') .. '.' ..
                                                field.option
                                        ] = true
                                end
                        end
                end
        end

        if has_upload then
                local uci = luci.model.uci.cursor()
                local prm = luci.http.context.request.message.params
                local fd, cbid

                luci.http.setfilehandler(
                        function( field, chunk, eof )
                                if not field then return end
                                if field.name and not cbid then
                                        local c, s, o = field.name:gmatch(
                                                "cbid%.([^%.]+)%.([^%.]+)%.([^%.]+)"
                                        )()

                                        if c and s and o then
                                                local t = uci:get( c, s ) or s
                                                if uploads[c.."."..t.."."..o] then
                                                        local path = upldir .. field.name
                                                        fd = io.open(path, "w")
                                                        if fd then
                                                                cbid = field.name
                                                                prm[cbid] = path
                                                        end
                                                end
                                        end
                                end

                                if field.name == cbid and fd then
                                        fd:write(chunk)
                                end

                                if eof and fd then
                                        fd:close()
                                        fd   = nil
                                        cbid = nil
                                end
                        end
                )
        end

        return maps
end

--
-- Compile a datatype specification into a parse tree for evaluation later on
--
local cdt_cache = { }

function compile_datatype(code)
        local i
        local pos = 0
        local esc = false
        local depth = 0
        local stack = { }

        for i = 1, #code+1 do
                local byte = code:byte(i) or 44
                if esc then
                        esc = false
                elseif byte == 92 then
                        esc = true
                elseif byte == 40 or byte == 44 then
                        if depth <= 0 then
                                if pos < i then
                                        local label = code:sub(pos, i-1)
                                                :gsub("\\(.)", "%1")
                                                :gsub("^%s+", "")
                                                :gsub("%s+$", "")

                                        if #label > 0 and tonumber(label) then
                                                stack[#stack+1] = tonumber(label)
                                        elseif label:match("^'.+'$") or label:match('^".+"$') then
                                                stack[#stack+1] = label:gsub("[\"'](.+)[\"']", "%1")
                                        elseif type(datatypes[label]) == "function" then
                                                stack[#stack+1] = datatypes[label]
                                                stack[#stack+1] = { }
                                        else
                                                error("Datatype error, bad token %q" % label)
                                        end
                                end
                                pos = i + 1
                        end
                        depth = depth + (byte == 40 and 1 or 0)
                elseif byte == 41 then
                        depth = depth - 1
                        if depth <= 0 then
                                if type(stack[#stack-1]) ~= "function" then
                                        error("Datatype error, argument list follows non-function")
                                end
                                stack[#stack] = compile_datatype(code:sub(pos, i-1))
                                pos = i + 1
                        end
                end
        end

        return stack
end

function verify_datatype(dt, value)
        if dt and #dt > 0 then
                if not cdt_cache[dt] then
                        local c = compile_datatype(dt)
                        if c and type(c[1]) == "function" then
                                cdt_cache[dt] = c
                        else
                                error("Datatype error, not a function expression")
                        end
                end
                if cdt_cache[dt] then
                        return cdt_cache[dt][1](value, unpack(cdt_cache[dt][2]))
                end
        end
        return true
end


-- Node pseudo abstract class
Node = class()

function Node.__init__(self, title, description)
        self.children = {}
        self.title = title or ""
        self.description = description or ""
        self.template = "cbi/node"
end

-- hook helper
function Node._run_hook(self, hook)
        if type(self[hook]) == "function" then
                return self[hook](self)
        end
end

function Node._run_hooks(self, ...)
        local f
        local r = false
        for _, f in ipairs(arg) do
                if type(self[f]) == "function" then
                        self[f](self)
                        r = true
                end
        end
        return r
end

-- Prepare nodes
function Node.prepare(self, ...)
        for k, child in ipairs(self.children) do
                child:prepare(...)
        end
end

-- Append child nodes
function Node.append(self, obj)
        table.insert(self.children, obj)
end

-- Parse this node and its children
function Node.parse(self, ...)
        for k, child in ipairs(self.children) do
                child:parse(...)
        end
end

-- Render this node
function Node.render(self, scope)
        scope = scope or {}
        scope.self = self

        luci.template.render(self.template, scope)
end

-- Render the children
function Node.render_children(self, ...)
        local k, node
        for k, node in ipairs(self.children) do
                node.last_child = (k == #self.children)
                node:render(...)
        end
end


--[[
A simple template element
]]--
Template = class(Node)

function Template.__init__(self, template)
        Node.__init__(self)
        self.template = template
end

function Template.render(self)
        luci.template.render(self.template, {self=self})
end

function Template.parse(self, readinput)
        self.readinput = (readinput ~= false)
        return Map.formvalue(self, "cbi.submit") and FORM_DONE or FORM_NODATA
end


--[[
Map - A map describing a configuration file
]]--
Map = class(Node)

function Map.__init__(self, config, ...)
        Node.__init__(self, ...)

        self.config = config
        self.parsechain = {self.config}
        self.template = "cbi/map"
        self.apply_on_parse = nil
        self.readinput = true
        self.proceed = false
        self.flow = {}

        self.uci = uci.cursor()
        self.save = true

        self.changed = false

        if not self.uci:load(self.config) then
                error("Unable to read UCI data: " .. self.config)
        end
end

function Map.formvalue(self, key)
        return self.readinput and luci.http.formvalue(key)
end

function Map.formvaluetable(self, key)
        return self.readinput and luci.http.formvaluetable(key) or {}
end

function Map.get_scheme(self, sectiontype, option)
        if not option then
                return self.scheme and self.scheme.sections[sectiontype]
        else
                return self.scheme and self.scheme.variables[sectiontype]
                 and self.scheme.variables[sectiontype][option]
        end
end

function Map.submitstate(self)
        return self:formvalue("cbi.submit")
end

-- Chain foreign config
function Map.chain(self, config)
        table.insert(self.parsechain, config)
end

function Map.state_handler(self, state)
        return state
end

-- Use optimized UCI writing
function Map.parse(self, readinput, ...)
        self.readinput = (readinput ~= false)
        self:_run_hooks("on_parse")

        if self:formvalue("cbi.skip") then
                self.state = FORM_SKIP
                return self:state_handler(self.state)
        end

        Node.parse(self, ...)

        if self.save then
                self:_run_hooks("on_save", "on_before_save")
                for i, config in ipairs(self.parsechain) do
                        self.uci:save(config)
                end
                self:_run_hooks("on_after_save")
                if self:submitstate() and ((not self.proceed and self.flow.autoapply) or luci.http.formvalue("cbi.apply")) then
                        self:_run_hooks("on_before_commit")
                        for i, config in ipairs(self.parsechain) do
                                self.uci:commit(config)

                                -- Refresh data because commit changes section names
                                self.uci:load(config)
                        end
                        self:_run_hooks("on_commit", "on_after_commit", "on_before_apply")
                        if self.apply_on_parse then
                                self.uci:apply(self.parsechain)
                                self:_run_hooks("on_apply", "on_after_apply")
                        else
                                -- This is evaluated by the dispatcher and delegated to the
                                -- template which in turn fires XHR to perform the actual
                                -- apply actions.
                                self.apply_needed = true
                        end

                        -- Reparse sections
                        Node.parse(self, true)

                end
                for i, config in ipairs(self.parsechain) do
                        self.uci:unload(config)
                end
                if type(self.commit_handler) == "function" then
                        self:commit_handler(self:submitstate())
                end
        end

        if self:submitstate() then
                if not self.save then
                        self.state = FORM_INVALID
                elseif self.proceed then
                        self.state = FORM_PROCEED
                else
                        self.state = self.changed and FORM_CHANGED or FORM_VALID
                end
        else
                self.state = FORM_NODATA
        end

        return self:state_handler(self.state)
end

function Map.render(self, ...)
        self:_run_hooks("on_init")
        Node.render(self, ...)
end

-- Creates a child section
function Map.section(self, class, ...)
        if instanceof(class, AbstractSection) then
                local obj  = class(self, ...)
                self:append(obj)
                return obj
        else
                error("class must be a descendent of AbstractSection")
        end
end

-- UCI add
function Map.add(self, sectiontype)
        return self.uci:add(self.config, sectiontype)
end

-- UCI set
function Map.set(self, section, option, value)
        if type(value) ~= "table" or #value > 0 then
                if option then
                        return self.uci:set(self.config, section, option, value)
                else
                        return self.uci:set(self.config, section, value)
                end
        else
                return Map.del(self, section, option)
        end
end

-- UCI del
function Map.del(self, section, option)
        if option then
                return self.uci:delete(self.config, section, option)
        else
                return self.uci:delete(self.config, section)
        end
end

-- UCI get
function Map.get(self, section, option)
        if not section then
                return self.uci:get_all(self.config)
        elseif option then
                return self.uci:get(self.config, section, option)
        else
                return self.uci:get_all(self.config, section)
        end
end

--[[
Compound - Container
]]--
Compound = class(Node)

function Compound.__init__(self, ...)
        Node.__init__(self)
        self.template = "cbi/compound"
        self.children = {...}
end

function Compound.populate_delegator(self, delegator)
        for _, v in ipairs(self.children) do
                v.delegator = delegator
        end
end

function Compound.parse(self, ...)
        local cstate, state = 0

        for k, child in ipairs(self.children) do
                cstate = child:parse(...)
                state = (not state or cstate < state) and cstate or state
        end

        return state
end


--[[
Delegator - Node controller
]]--
Delegator = class(Node)
function Delegator.__init__(self, ...)
        Node.__init__(self, ...)
        self.nodes = {}
        self.defaultpath = {}
        self.pageaction = false
        self.readinput = true
        self.allow_reset = false
        self.allow_cancel = false
        self.allow_back = false
        self.allow_finish = false
        self.template = "cbi/delegator"
end

function Delegator.set(self, name, node)
        assert(not self.nodes[name], "Duplicate entry")

        self.nodes[name] = node
end

function Delegator.add(self, name, node)
        node = self:set(name, node)
        self.defaultpath[#self.defaultpath+1] = name
end

function Delegator.insert_after(self, name, after)
        local n = #self.chain + 1
        for k, v in ipairs(self.chain) do
                if v == after then
                        n = k + 1
                        break
                end
        end
        table.insert(self.chain, n, name)
end

function Delegator.set_route(self, ...)
        local n, chain, route = 0, self.chain, {...}
        for i = 1, #chain do
                if chain[i] == self.current then
                        n = i
                        break
                end
        end
        for i = 1, #route do
                n = n + 1
                chain[n] = route[i]
        end
        for i = n + 1, #chain do
                chain[i] = nil
        end
end

function Delegator.get(self, name)
        local node = self.nodes[name]

        if type(node) == "string" then
                node = load(node, name)
        end

        if type(node) == "table" and getmetatable(node) == nil then
                node = Compound(unpack(node))
        end

        return node
end

function Delegator.parse(self, ...)
        if self.allow_cancel and Map.formvalue(self, "cbi.cancel") then
                if self:_run_hooks("on_cancel") then
                        return FORM_DONE
                end
        end

        if not Map.formvalue(self, "cbi.delg.current") then
                self:_run_hooks("on_init")
        end

        local newcurrent
        self.chain = self.chain or self:get_chain()
        self.current = self.current or self:get_active()
        self.active = self.active or self:get(self.current)
        assert(self.active, "Invalid state")

        local stat = FORM_DONE
        if type(self.active) ~= "function" then
                self.active:populate_delegator(self)
                stat = self.active:parse()
        else
                self:active()
        end

        if stat > FORM_PROCEED then
                if Map.formvalue(self, "cbi.delg.back") then
                        newcurrent = self:get_prev(self.current)
                else
                        newcurrent = self:get_next(self.current)
                end
        elseif stat < FORM_PROCEED then
                return stat
        end


        if not Map.formvalue(self, "cbi.submit") then
                return FORM_NODATA
        elseif stat > FORM_PROCEED
        and (not newcurrent or not self:get(newcurrent)) then
                return self:_run_hook("on_done") or FORM_DONE
        else
                self.current = newcurrent or self.current
                self.active = self:get(self.current)
                if type(self.active) ~= "function" then
                        self.active:populate_delegator(self)
                        local stat = self.active:parse(false)
                        if stat == FORM_SKIP then
                                return self:parse(...)
                        else
                                return FORM_PROCEED
                        end
                else
                        return self:parse(...)
                end
        end
end

function Delegator.get_next(self, state)
        for k, v in ipairs(self.chain) do
                if v == state then
                        return self.chain[k+1]
                end
        end
end

function Delegator.get_prev(self, state)
        for k, v in ipairs(self.chain) do
                if v == state then
                        return self.chain[k-1]
                end
        end
end

function Delegator.get_chain(self)
        local x = Map.formvalue(self, "cbi.delg.path") or self.defaultpath
        return type(x) == "table" and x or {x}
end

function Delegator.get_active(self)
        return Map.formvalue(self, "cbi.delg.current") or self.chain[1]
end

--[[
Page - A simple node
]]--

Page = class(Node)
Page.__init__ = Node.__init__
Page.parse    = function() end


--[[
SimpleForm - A Simple non-UCI form
]]--
SimpleForm = class(Node)

function SimpleForm.__init__(self, config, title, description, data)
        Node.__init__(self, title, description)
        self.config = config
        self.data = data or {}
        self.template = "cbi/simpleform"
        self.dorender = true
        self.pageaction = false
        self.readinput = true
end

SimpleForm.formvalue = Map.formvalue
SimpleForm.formvaluetable = Map.formvaluetable

function SimpleForm.parse(self, readinput, ...)
        self.readinput = (readinput ~= false)

        if self:formvalue("cbi.skip") then
                return FORM_SKIP
        end

        if self:formvalue("cbi.cancel") and self:_run_hooks("on_cancel") then
                return FORM_DONE
        end

        if self:submitstate() then
                Node.parse(self, 1, ...)
        end

        local valid = true
        for k, j in ipairs(self.children) do
                for i, v in ipairs(j.children) do
                        valid = valid
                         and (not v.tag_missing or not v.tag_missing[1])
                         and (not v.tag_invalid or not v.tag_invalid[1])
                         and (not v.error)
                end
        end

        local state =
                not self:submitstate() and FORM_NODATA
                or valid and FORM_VALID
                or FORM_INVALID

        self.dorender = not self.handle
        if self.handle then
                local nrender, nstate = self:handle(state, self.data)
                self.dorender = self.dorender or (nrender ~= false)
                state = nstate or state
        end
        return state
end

function SimpleForm.render(self, ...)
        if self.dorender then
                Node.render(self, ...)
        end
end

function SimpleForm.submitstate(self)
        return self:formvalue("cbi.submit")
end

function SimpleForm.section(self, class, ...)
        if instanceof(class, AbstractSection) then
                local obj  = class(self, ...)
                self:append(obj)
                return obj
        else
                error("class must be a descendent of AbstractSection")
        end
end

-- Creates a child field
function SimpleForm.field(self, class, ...)
        local section
        for k, v in ipairs(self.children) do
                if instanceof(v, SimpleSection) then
                        section = v
                        break
                end
        end
        if not section then
                section = self:section(SimpleSection)
        end

        if instanceof(class, AbstractValue) then
                local obj  = class(self, section, ...)
                obj.track_missing = true
                section:append(obj)
                return obj
        else
                error("class must be a descendent of AbstractValue")
        end
end

function SimpleForm.set(self, section, option, value)
        self.data[option] = value
end


function SimpleForm.del(self, section, option)
        self.data[option] = nil
end


function SimpleForm.get(self, section, option)
        return self.data[option]
end


function SimpleForm.get_scheme()
        return nil
end


Form = class(SimpleForm)

function Form.__init__(self, ...)
        SimpleForm.__init__(self, ...)
        self.embedded = true
end


--[[
AbstractSection
]]--
AbstractSection = class(Node)

function AbstractSection.__init__(self, map, sectiontype, ...)
        Node.__init__(self, ...)
        self.sectiontype = sectiontype
        self.map = map
        self.config = map.config
        self.optionals = {}
        self.defaults = {}
        self.fields = {}
        self.tag_error = {}
        self.tag_invalid = {}
        self.tag_deperror = {}
        self.changed = false

        self.optional = true
        self.addremove = false
        self.dynamic = false
end

-- Define a tab for the section
function AbstractSection.tab(self, tab, title, desc)
        self.tabs      = self.tabs      or { }
        self.tab_names = self.tab_names or { }

        self.tab_names[#self.tab_names+1] = tab
        self.tabs[tab] = {
                title       = title,
                description = desc,
                childs      = { }
        }
end

-- Check whether the section has tabs
function AbstractSection.has_tabs(self)
        return (self.tabs ~= nil) and (next(self.tabs) ~= nil)
end

-- Appends a new option
function AbstractSection.option(self, class, option, ...)
        if instanceof(class, AbstractValue) then
                local obj  = class(self.map, self, option, ...)
                self:append(obj)
                self.fields[option] = obj
                return obj
        elseif class == true then
                error("No valid class was given and autodetection failed.")
        else
                error("class must be a descendant of AbstractValue")
        end
end

-- Appends a new tabbed option
function AbstractSection.taboption(self, tab, ...)

        assert(tab and self.tabs and self.tabs[tab],
                "Cannot assign option to not existing tab %q" % tostring(tab))

        local l = self.tabs[tab].childs
        local o = AbstractSection.option(self, ...)

        if o then l[#l+1] = o end

        return o
end

-- Render a single tab
function AbstractSection.render_tab(self, tab, ...)

        assert(tab and self.tabs and self.tabs[tab],
                "Cannot render not existing tab %q" % tostring(tab))

        local k, node
        for k, node in ipairs(self.tabs[tab].childs) do
                node.last_child = (k == #self.tabs[tab].childs)
                node:render(...)
        end
end

-- Parse optional options
function AbstractSection.parse_optionals(self, section)
        if not self.optional then
                return
        end

        self.optionals[section] = {}

        local field = self.map:formvalue("cbi.opt."..self.config.."."..section)
        for k,v in ipairs(self.children) do
                if v.optional and not v:cfgvalue(section) and not self:has_tabs() then
                        if field == v.option then
                                field = nil
                                self.map.proceed = true
                        else
                                table.insert(self.optionals[section], v)
                        end
                end
        end

        if field and #field > 0 and self.dynamic then
                self:add_dynamic(field)
        end
end

-- Add a dynamic option
function AbstractSection.add_dynamic(self, field, optional)
        local o = self:option(Value, field, field)
        o.optional = optional
end

-- Parse all dynamic options
function AbstractSection.parse_dynamic(self, section)
        if not self.dynamic then
                return
        end

        local arr  = luci.util.clone(self:cfgvalue(section))
        local form = self.map:formvaluetable("cbid."..self.config.."."..section)
        for k, v in pairs(form) do
                arr[k] = v
        end

        for key,val in pairs(arr) do
                local create = true

                for i,c in ipairs(self.children) do
                        if c.option == key then
                                create = false
                        end
                end

                if create and key:sub(1, 1) ~= "." then
                        self.map.proceed = true
                        self:add_dynamic(key, true)
                end
        end
end

-- Returns the section's UCI table
function AbstractSection.cfgvalue(self, section)
        return self.map:get(section)
end

-- Push events
function AbstractSection.push_events(self)
        --luci.util.append(self.map.events, self.events)
        self.map.changed = true
end

-- Removes the section
function AbstractSection.remove(self, section)
        self.map.proceed = true
        return self.map:del(section)
end

-- Creates the section
function AbstractSection.create(self, section)
        local stat

        if section then
                stat = section:match("^[%w_]+$") and self.map:set(section, nil, self.sectiontype)
        else
                section = self.map:add(self.sectiontype)
                stat = section
        end

        if stat then
                for k,v in pairs(self.children) do
                        if v.default then
                                self.map:set(section, v.option, v.default)
                        end
                end

                for k,v in pairs(self.defaults) do
                        self.map:set(section, k, v)
                end
        end

        self.map.proceed = true

        return stat
end


SimpleSection = class(AbstractSection)

function SimpleSection.__init__(self, form, ...)
        AbstractSection.__init__(self, form, nil, ...)
        self.template = "cbi/nullsection"
end


Table = class(AbstractSection)

function Table.__init__(self, form, data, ...)
        local datasource = {}
        local tself = self
        datasource.config = "table"
        self.data = data or {}

        datasource.formvalue = Map.formvalue
        datasource.formvaluetable = Map.formvaluetable
        datasource.readinput = true

        function datasource.get(self, section, option)
                return tself.data[section] and tself.data[section][option]
        end

        function datasource.submitstate(self)
                return Map.formvalue(self, "cbi.submit")
        end

        function datasource.del(...)
                return true
        end

        function datasource.get_scheme()
                return nil
        end

        AbstractSection.__init__(self, datasource, "table", ...)
        self.template = "cbi/tblsection"
        self.rowcolors = true
        self.anonymous = true
end

function Table.parse(self, readinput)
        self.map.readinput = (readinput ~= false)
        for i, k in ipairs(self:cfgsections()) do
                if self.map:submitstate() then
                        Node.parse(self, k)
                end
        end
end

function Table.cfgsections(self)
        local sections = {}

        for i, v in luci.util.kspairs(self.data) do
                table.insert(sections, i)
        end

        return sections
end

function Table.update(self, data)
        self.data = data
end



--[[
NamedSection - A fixed configuration section defined by its name
]]--
NamedSection = class(AbstractSection)

function NamedSection.__init__(self, map, section, stype, ...)
        AbstractSection.__init__(self, map, stype, ...)

        -- Defaults
        self.addremove = false
        self.template = "cbi/nsection"
        self.section = section
end

function NamedSection.parse(self, novld)
        local s = self.section
        local active = self:cfgvalue(s)

        if self.addremove then
                local path = self.config.."."..s
                if active then -- Remove the section
                        if self.map:formvalue("cbi.rns."..path) and self:remove(s) then
                                self:push_events()
                                return
                        end
                else           -- Create and apply default values
                        if self.map:formvalue("cbi.cns."..path) then
                                self:create(s)
                                return
                        end
                end
        end

        if active then
                AbstractSection.parse_dynamic(self, s)
                if self.map:submitstate() then
                        Node.parse(self, s)
                end
                AbstractSection.parse_optionals(self, s)

                if self.changed then
                        self:push_events()
                end
        end
end


--[[
TypedSection - A (set of) configuration section(s) defined by the type
        addremove:      Defines whether the user can add/remove sections of this type
        anonymous:  Allow creating anonymous sections
        validate:       a validation function returning nil if the section is invalid
]]--
TypedSection = class(AbstractSection)

function TypedSection.__init__(self, map, type, ...)
        AbstractSection.__init__(self, map, type, ...)

        self.template = "cbi/tsection"
        self.deps = {}
        self.anonymous = false
end

-- Return all matching UCI sections for this TypedSection
function TypedSection.cfgsections(self)
        local sections = {}
        self.map.uci:foreach(self.map.config, self.sectiontype,
                function (section)
                        if self:checkscope(section[".name"]) then
                                table.insert(sections, section[".name"])
                        end
                end)

        return sections
end

-- Limits scope to sections that have certain option => value pairs
function TypedSection.depends(self, option, value)
        table.insert(self.deps, {option=option, value=value})
end

function TypedSection.parse(self, novld)
        if self.addremove then
                -- Remove
                local crval = REMOVE_PREFIX .. self.config
                local name = self.map:formvaluetable(crval)
                for k,v in pairs(name) do
                        if k:sub(-2) == ".x" then
                                k = k:sub(1, #k - 2)
                        end
                        if self:cfgvalue(k) and self:checkscope(k) then
                                self:remove(k)
                        end
                end
        end

        local co
        for i, k in ipairs(self:cfgsections()) do
                AbstractSection.parse_dynamic(self, k)
                if self.map:submitstate() then
                        Node.parse(self, k, novld)
                end
                AbstractSection.parse_optionals(self, k)
        end

        if self.addremove then
                -- Create
                local created
                local crval = CREATE_PREFIX .. self.config .. "." .. self.sectiontype
                local origin, name = next(self.map:formvaluetable(crval))
                if self.anonymous then
                        if name then
                                created = self:create(nil, origin)
                        end
                else
                        if name then
                                -- Ignore if it already exists
                                if self:cfgvalue(name) then
                                        name = nil;
                                end

                                name = self:checkscope(name)

                                if not name then
                                        self.err_invalid = true
                                end

                                if name and #name > 0 then
                                        created = self:create(name, origin) and name
                                        if not created then
                                                self.invalid_cts = true
                                        end
                                end
                        end
                end

                if created then
                        AbstractSection.parse_optionals(self, created)
                end
        end

        if self.sortable then
                local stval = RESORT_PREFIX .. self.config .. "." .. self.sectiontype
                local order = self.map:formvalue(stval)
                if order and #order > 0 then
                        local sid
                        local num = 0
                        for sid in util.imatch(order) do
                                self.map.uci:reorder(self.config, sid, num)
                                num = num + 1
                        end
                        self.changed = (num > 0)
                end
        end

        if created or self.changed then
                self:push_events()
        end
end

-- Verifies scope of sections
function TypedSection.checkscope(self, section)
        -- Check if we are not excluded
        if self.filter and not self:filter(section) then
                return nil
        end

        -- Check if at least one dependency is met
        if #self.deps > 0 and self:cfgvalue(section) then
                local stat = false

                for k, v in ipairs(self.deps) do
                        if self:cfgvalue(section)[v.option] == v.value then
                                stat = true
                        end
                end

                if not stat then
                        return nil
                end
        end

        return self:validate(section)
end


-- Dummy validate function
function TypedSection.validate(self, section)
        return section
end


--[[
AbstractValue - An abstract Value Type
        null:           Value can be empty
        valid:          A function returning the value if it is valid otherwise nil
        depends:        A table of option => value pairs of which one must be true
        default:        The default value
        size:           The size of the input fields
        rmempty:        Unset value if empty
        optional:       This value is optional (see AbstractSection.optionals)
]]--
AbstractValue = class(Node)

function AbstractValue.__init__(self, map, section, option, ...)
        Node.__init__(self, ...)
        self.section = section
        self.option  = option
        self.map     = map
        self.config  = map.config
        self.tag_invalid = {}
        self.tag_missing = {}
        self.tag_reqerror = {}
        self.tag_error = {}
        self.deps = {}
        self.subdeps = {}
        --self.cast = "string"

        self.track_missing = false
        self.rmempty   = true
        self.default   = nil
        self.size      = nil
        self.optional  = false
end

function AbstractValue.prepare(self)
        self.cast = self.cast or "string"
end

-- Add a dependencie to another section field
function AbstractValue.depends(self, field, value)
        local deps
        if type(field) == "string" then
                deps = {}
                deps[field] = value
        else
                deps = field
        end

        table.insert(self.deps, {deps=deps, add=""})
end

-- Generates the unique CBID
function AbstractValue.cbid(self, section)
        return "cbid."..self.map.config.."."..section.."."..self.option
end

-- Return whether this object should be created
function AbstractValue.formcreated(self, section)
        local key = "cbi.opt."..self.config.."."..section
        return (self.map:formvalue(key) == self.option)
end

-- Returns the formvalue for this object
function AbstractValue.formvalue(self, section)
        return self.map:formvalue(self:cbid(section))
end

function AbstractValue.additional(self, value)
        self.optional = value
end

function AbstractValue.mandatory(self, value)
        self.rmempty = not value
end

function AbstractValue.add_error(self, section, type, msg)
        self.error = self.error or { }
        self.error[section] = msg or type

        self.section.error = self.section.error or { }
        self.section.error[section] = self.section.error[section] or { }
        table.insert(self.section.error[section], msg or type)

        if type == "invalid" then
                self.tag_invalid[section] = true
        elseif type == "missing" then
                self.tag_missing[section] = true
        end

        self.tag_error[section] = true
        self.map.save = false
end

function AbstractValue.parse(self, section, novld)
        local fvalue = self:formvalue(section)
        local cvalue = self:cfgvalue(section)

        -- If favlue and cvalue are both tables and have the same content
        -- make them identical
        if type(fvalue) == "table" and type(cvalue) == "table" then
                local equal = #fvalue == #cvalue
                if equal then
                        for i=1, #fvalue do
                                if cvalue[i] ~= fvalue[i] then
                                        equal = false
                                end
                        end
                end
                if equal then
                        fvalue = cvalue
                end
        end

        if fvalue and #fvalue > 0 then -- If we have a form value, write it to UCI
                local val_err
                fvalue, val_err = self:validate(fvalue, section)
                fvalue = self:transform(fvalue)

                if not fvalue and not novld then
                        self:add_error(section, "invalid", val_err)
                end

                if fvalue and (self.forcewrite or not (fvalue == cvalue)) then
                        if self:write(section, fvalue) then
                                -- Push events
                                self.section.changed = true
                                --luci.util.append(self.map.events, self.events)
                        end
                end
        else                                                    -- Unset the UCI or error
                if self.rmempty or self.optional then
                        if self:remove(section) then
                                -- Push events
                                self.section.changed = true
                                --luci.util.append(self.map.events, self.events)
                        end
                elseif cvalue ~= fvalue and not novld then
                        -- trigger validator with nil value to get custom user error msg.
                        local _, val_err = self:validate(nil, section)
                        self:add_error(section, "missing", val_err)
                end
        end
end

-- Render if this value exists or if it is mandatory
function AbstractValue.render(self, s, scope)
        if not self.optional or self.section:has_tabs() or self:cfgvalue(s) or self:formcreated(s) then
                scope = scope or {}
                scope.section = s
                scope.cbid    = self:cbid(s)
                Node.render(self, scope)
        end
end

-- Return the UCI value of this object
function AbstractValue.cfgvalue(self, section)
        local value
        if self.tag_error[section] then
                value = self:formvalue(section)
        else
                value = self.map:get(section, self.option)
        end

        if not value then
                return nil
        elseif not self.cast or self.cast == type(value) then
                return value
        elseif self.cast == "string" then
                if type(value) == "table" then
                        return value[1]
                end
        elseif self.cast == "table" then
                return { value }
        end
end

-- Validate the form value
function AbstractValue.validate(self, value)
        if self.datatype and value then
                if type(value) == "table" then
                        local v
                        for _, v in ipairs(value) do
                                if v and #v > 0 and not verify_datatype(self.datatype, v) then
                                        error('F')
                                        return nil
                                end
                        end
                else
                        if not verify_datatype(self.datatype, value) then
                                error('F')
                                return nil
                        end
                end
        end

        return value
end

AbstractValue.transform = AbstractValue.validate


-- Write to UCI
function AbstractValue.write(self, section, value)
        return self.map:set(section, self.option, value)
end

-- Remove from UCI
function AbstractValue.remove(self, section)
        return self.map:del(section, self.option)
end




--[[
Value - A one-line value
        maxlength:      The maximum length
]]--
Value = class(AbstractValue)

function Value.__init__(self, ...)
        AbstractValue.__init__(self, ...)
        self.template  = "cbi/value"
        self.keylist = {}
        self.vallist = {}
end

function Value.reset_values(self)
        self.keylist = {}
        self.vallist = {}
end

function Value.value(self, key, val)
        val = val or key
        table.insert(self.keylist, tostring(key))
        table.insert(self.vallist, tostring(val))
end


-- DummyValue - This does nothing except being there
DummyValue = class(AbstractValue)

function DummyValue.__init__(self, ...)
        AbstractValue.__init__(self, ...)
        self.template = "cbi/dvalue"
        self.value = nil
end

function DummyValue.cfgvalue(self, section)
        local value
        if self.value then
                if type(self.value) == "function" then
                        value = self:value(section)
                else
                        value = self.value
                end
        else
                value = AbstractValue.cfgvalue(self, section)
        end
        return value
end

function DummyValue.parse(self)

end


--[[
Flag - A flag being enabled or disabled
]]--
Flag = class(AbstractValue)

function Flag.__init__(self, ...)
        AbstractValue.__init__(self, ...)
        self.template  = "cbi/fvalue"

        self.enabled  = "1"
        self.disabled = "0"
        self.default  = self.disabled
end

-- A flag can only have two states: set or unset
function Flag.parse(self, section)
        local fexists = self.map:formvalue(
                FEXIST_PREFIX .. self.config .. "." .. section .. "." .. self.option)

        if fexists then
                local fvalue = self:formvalue(section) and self.enabled or self.disabled
                if fvalue ~= self.default or (not self.optional and not self.rmempty) then
                        self:write(section, fvalue)
                else
                        self:remove(section)
                end
        else
                self:remove(section)
        end
end

function Flag.cfgvalue(self, section)
        return AbstractValue.cfgvalue(self, section) or self.default
end


--[[
ListValue - A one-line value predefined in a list
        widget: The widget that will be used (select, radio)
]]--
ListValue = class(AbstractValue)

function ListValue.__init__(self, ...)
        AbstractValue.__init__(self, ...)
        self.template  = "cbi/lvalue"

        self.keylist = {}
        self.vallist = {}
        self.size   = 1
        self.widget = "select"
end

function ListValue.reset_values(self)
        self.keylist = {}
        self.vallist = {}
end

function ListValue.value(self, key, val, ...)
        if luci.util.contains(self.keylist, key) then
                return
        end

        val = val or key
        table.insert(self.keylist, tostring(key))
        table.insert(self.vallist, tostring(val))

        for i, deps in ipairs({...}) do
                self.subdeps[#self.subdeps + 1] = {add = "-"..key, deps=deps}
        end
end

function ListValue.validate(self, val)
        if luci.util.contains(self.keylist, val) then
                return val
        else
                return nil
        end
end



--[[
MultiValue - Multiple delimited values
        widget: The widget that will be used (select, checkbox)
        delimiter: The delimiter that will separate the values (default: " ")
]]--
MultiValue = class(AbstractValue)

function MultiValue.__init__(self, ...)
        AbstractValue.__init__(self, ...)
        self.template = "cbi/mvalue"

        self.keylist = {}
        self.vallist = {}

        self.widget = "checkbox"
        self.delimiter = " "
end

function MultiValue.render(self, ...)
        if self.widget == "select" and not self.size then
                self.size = #self.vallist
        end

        AbstractValue.render(self, ...)
end

function MultiValue.reset_values(self)
        self.keylist = {}
        self.vallist = {}
end

function MultiValue.value(self, key, val)
        if luci.util.contains(self.keylist, key) then
                return
        end

        val = val or key
        table.insert(self.keylist, tostring(key))
        table.insert(self.vallist, tostring(val))
end

function MultiValue.valuelist(self, section)
        local val = self:cfgvalue(section)

        if not(type(val) == "string") then
                return {}
        end

        return luci.util.split(val, self.delimiter)
end

function MultiValue.validate(self, val)
        val = (type(val) == "table") and val or {val}

        local result

        for i, value in ipairs(val) do
                if luci.util.contains(self.keylist, value) then
                        result = result and (result .. self.delimiter .. value) or value
                end
        end

        return result
end


StaticList = class(MultiValue)

function StaticList.__init__(self, ...)
        MultiValue.__init__(self, ...)
        self.cast = "table"
        self.valuelist = self.cfgvalue

        if not self.override_scheme
         and self.map:get_scheme(self.section.sectiontype, self.option) then
                local vs = self.map:get_scheme(self.section.sectiontype, self.option)
                if self.value and vs.values and not self.override_values then
                        for k, v in pairs(vs.values) do
                                self:value(k, v)
                        end
                end
        end
end

function StaticList.validate(self, value)
        value = (type(value) == "table") and value or {value}

        local valid = {}
        for i, v in ipairs(value) do
                if luci.util.contains(self.keylist, v) then
                        table.insert(valid, v)
                end
        end
        return valid
end


DynamicList = class(AbstractValue)

function DynamicList.__init__(self, ...)
        AbstractValue.__init__(self, ...)
        self.template  = "cbi/dynlist"
        self.cast = "table"
        self.keylist = {}
        self.vallist = {}
end

function DynamicList.reset_values(self)
        self.keylist = {}
        self.vallist = {}
end

function DynamicList.value(self, key, val)
        val = val or key
        table.insert(self.keylist, tostring(key))
        table.insert(self.vallist, tostring(val))
end

function DynamicList.write(self, section, value)
        local t = { }

        if type(value) == "table" then
                local x
                for _, x in ipairs(value) do
                        if x and #x > 0 then
                                t[#t+1] = x
                        end
                end
        else
                t = { value }
        end

        if self.cast == "string" then
                value = table.concat(t, " ")
        else
                value = t
        end

        return AbstractValue.write(self, section, value)
end

function DynamicList.cfgvalue(self, section)
        local value = AbstractValue.cfgvalue(self, section)

        if type(value) == "string" then
                local x
                local t = { }
                for x in value:gmatch("%S+") do
                        if #x > 0 then
                                t[#t+1] = x
                        end
                end
                value = t
        end

        return value
end

function DynamicList.formvalue(self, section)
        local value = AbstractValue.formvalue(self, section)

        if type(value) == "string" then
                if self.cast == "string" then
                        local x
                        local t = { }
                        for x in value:gmatch("%S+") do
                                t[#t+1] = x
                        end
                        value = t
                else
                        value = { value }
                end
        end

        return value
end


--[[
TextValue - A multi-line value
        rows:   Rows
]]--
TextValue = class(AbstractValue)

function TextValue.__init__(self, ...)
        AbstractValue.__init__(self, ...)
        self.template  = "cbi/tvalue"
end

--[[
Button
]]--
Button = class(AbstractValue)

function Button.__init__(self, ...)
        AbstractValue.__init__(self, ...)
        self.template  = "cbi/button"
        self.inputstyle = nil
        self.rmempty = true
end


FileUpload = class(AbstractValue)

function FileUpload.__init__(self, ...)
        AbstractValue.__init__(self, ...)
        self.template = "cbi/upload"
        if not self.map.upload_fields then
                self.map.upload_fields = { self }
        else
                self.map.upload_fields[#self.map.upload_fields+1] = self
        end
end

function FileUpload.formcreated(self, section)
        return AbstractValue.formcreated(self, section) or
                self.map:formvalue("cbi.rlf."..section.."."..self.option) or
                self.map:formvalue("cbi.rlf."..section.."."..self.option..".x")
end

function FileUpload.cfgvalue(self, section)
        local val = AbstractValue.cfgvalue(self, section)
        if val and fs.access(val) then
                return val
        end
        return nil
end

function FileUpload.formvalue(self, section)
        local val = AbstractValue.formvalue(self, section)
        if val then
                if not self.map:formvalue("cbi.rlf."..section.."."..self.option) and
                   not self.map:formvalue("cbi.rlf."..section.."."..self.option..".x")
                then
                        return val
                end
                fs.unlink(val)
                self.value = nil
        end
        return nil
end

function FileUpload.remove(self, section)
        local val = AbstractValue.formvalue(self, section)
        if val and fs.access(val) then fs.unlink(val) end
        return AbstractValue.remove(self, section)
end


FileBrowser = class(AbstractValue)

function FileBrowser.__init__(self, ...)
        AbstractValue.__init__(self, ...)
        self.template = "cbi/browser"
end