* luci/libs/uvl: implement default value option for variable sections
[project/luci.git] / libs / uvl / luasrc / uvl.lua
1 --[[
2
3 UCI Validation Layer - Main Library
4 (c) 2008 Jo-Philipp Wich <xm@leipzig.freifunk.net>
5 (c) 2008 Steven Barth <steven@midlink.org>
6
7 Licensed under the Apache License, Version 2.0 (the "License");
8 you may not use this file except in compliance with the License.
9 You may obtain a copy of the License at
10
11         http://www.apache.org/licenses/LICENSE-2.0
12
13 $Id$
14
15 ]]--
16
17
18 --- UVL - UCI Validation Layer
19 -- @class       module
20 -- @cstyle      instance
21
22 module( "luci.uvl", package.seeall )
23
24 require("luci.fs")
25 require("luci.util")
26 require("luci.model.uci")
27 require("luci.uvl.errors")
28 require("luci.uvl.datatypes")
29 require("luci.uvl.validation")
30 require("luci.uvl.dependencies")
31
32
33 TYPE_SCHEME   = 0x00
34 TYPE_CONFIG   = 0x01
35 TYPE_SECTION  = 0x02
36 TYPE_OPTION   = 0x03
37 TYPE_ENUM     = 0x04
38
39 --- Boolean; default true;
40 -- treat sections found in config but not in scheme as error
41 STRICT_UNKNOWN_SECTIONS    = true
42
43 --- Boolean; default true;
44 -- treat options found in config but not in scheme as error
45 STRICT_UNKNOWN_OPTIONS     = true
46
47 --- Boolean; default true;
48 -- treat failed external validators as error
49 STRICT_EXTERNAL_VALIDATORS = true
50
51 --- Boolean; default true;
52 -- treat list values stored as options like errors
53 STRICT_LIST_TYPE           = true
54
55
56 local default_schemedir = "/lib/uci/schema"
57 local default_savedir = "/tmp/.uvl"
58 local ERR = luci.uvl.errors
59
60
61 --- Object constructor
62 -- @class                       function
63 -- @name                        UVL
64 -- @param schemedir     Path to the scheme directory (optional)
65 -- @return                      Instance object
66 UVL = luci.util.class()
67
68 function UVL.__init__( self, schemedir )
69         self.schemedir  = schemedir or default_schemedir
70         self.packages   = { }
71         self.beenthere  = { }
72         self.depseen    = { }
73         self.uci                = luci.model.uci
74         self.err                = luci.uvl.errors
75         self.dep                = luci.uvl.dependencies
76         self.datatypes  = luci.uvl.datatypes
77 end
78
79
80 --- Parse given scheme and return the scheme tree.
81 -- @param scheme        Name of the scheme to parse
82 -- @return                      Table containing the parsed scheme or nil on error
83 -- @return                      String containing the reason for errors (if any)
84 function UVL.get_scheme( self, scheme )
85         if not self.packages[scheme] then
86                 local ok, err = self:read_scheme( scheme )
87                 if not ok then
88                         return nil, err
89                 end
90         end
91         return self.packages[scheme], nil
92 end
93
94 --- Validate given configuration, section or option.
95 -- @param config        Name of the configuration to validate
96 -- @param section       Name of the section to validate (optional)
97 -- @param option        Name of the option to validate (optional)
98 -- @return                      Boolean indicating whether the given config validates
99 -- @return                      String containing the reason for errors (if any)
100 function UVL.validate( self, config, section, option )
101         if config and section and option then
102                 return self:validate_option( config, section, option )
103         elseif config and section then
104                 return self:validate_section( config, section )
105         elseif config then
106                 return self:validate_config( config )
107         end
108 end
109
110 --- Validate given configuration.
111 -- @param config        Name of the configuration to validate
112 -- @return                      Boolean indicating whether the given config validates
113 -- @return                      String containing the reason for errors (if any)
114 function UVL.validate_config( self, config, uci )
115
116         if not self.packages[config] then
117                 local ok, err = self:read_scheme(config)
118                 if not ok then
119                         return false, err
120                 end
121         end
122
123         local co = luci.uvl.config( self, uci or config, uci and config )
124         local sc = { }
125
126         self.beenthere = { }
127         self.depseen   = { }
128
129         if not co:config() then
130                 return false, co:errors()
131         end
132
133         local function _uci_foreach( type, func )
134                 for k, v in pairs(co:config()) do
135                         if v['.type'] == type then
136                                 sc[type] = sc[type] + 1
137                                 local ok, err = func( k, v )
138                                 if not ok then co:error(err) end
139                         end
140                 end
141         end
142
143         for k, v in pairs( self.packages[config].sections ) do
144                 sc[k] = 0
145                 _uci_foreach( k,
146                         function(s)
147                                 return self:_validate_section( co:section(s) )
148                         end
149                 )
150         end
151
152         if STRICT_UNKNOWN_SECTIONS then
153                 for k, v in pairs(co:config()) do
154                         local so = co:section(k)
155                         if not self.beenthere[so:cid()] then
156                                 co:error(ERR.SECT_UNKNOWN(so))
157                         end
158                 end
159         end
160
161         for _, k in ipairs(luci.util.keys(sc)) do
162                 local so = co:section(k)
163                 if so:scheme('required') and sc[k] == 0 then
164                         co:error(ERR.SECT_REQUIRED(so))
165                 elseif so:scheme('unique') and sc[k] > 1 then
166                         co:error(ERR.SECT_UNIQUE(so))
167                 end
168         end
169
170         return co:ok(), co:errors()
171 end
172
173 --- Validate given config section.
174 -- @param config        Name of the configuration to validate
175 -- @param section       Name of the section to validate
176 -- @return                      Boolean indicating whether the given config validates
177 -- @return                      String containing the reason for errors (if any)
178 function UVL.validate_section( self, config, section, uci )
179
180         if not self.packages[config] then
181                 local ok, err = self:read_scheme( config )
182                 if not ok then
183                         return false, err
184                 end
185         end
186
187         local co = luci.uvl.config( self, uci or config, uci and config )
188         local so = co:section( section )
189
190         self.beenthere = { }
191         self.depseen   = { }
192
193         if not co:config() then
194                 return false, co:errors()
195         end
196
197         if so:config() then
198                 return self:_validate_section( so )
199         else
200                 return false, ERR.SECT_NOTFOUND(so)
201         end
202 end
203
204 --- Validate given config option.
205 -- @param config        Name of the configuration to validate
206 -- @param section       Name of the section to validate
207 -- @param option        Name of the option to validate
208 -- @return                      Boolean indicating whether the given config validates
209 -- @return                      String containing the reason for errors (if any)
210 function UVL.validate_option( self, config, section, option, uci )
211
212         if not self.packages[config] then
213                 local ok, err = self:read_scheme( config )
214                 if not ok then
215                         return false, err
216                 end
217         end
218
219         local co = luci.uvl.config( self, uci or config, uci and config )
220         local so = co:section( section )
221         local oo = so:option( option )
222
223         if not co:config() then
224                 return false, co:errors()
225         end
226
227         if so:config() and oo:config() then
228                 return self:_validate_option( oo )
229         else
230                 return false, ERR.OPT_NOTFOUND(oo)
231         end
232 end
233
234
235 function UVL._validate_section( self, section )
236
237         self.beenthere[section:cid()] = true
238
239         if section:config() then
240                 if section:scheme('named') == true and
241                    section:config('.anonymous') == true
242                 then
243                         return false, ERR.SECT_NAMED(section)
244                 end
245
246                 for _, v in ipairs(section:variables()) do
247                         local ok, err = self:_validate_option( v )
248                         if not ok and (
249                                 v:scheme('required') or v:scheme('type') == "enum" or (
250                                         not err:is(ERR.ERR_DEP_NOTEQUAL) and
251                                         not err:is(ERR.ERR_DEP_NOVALUE)
252                                 )
253                         ) then
254                                 section:error(err)
255                         end
256                 end
257
258                 local ok, err = luci.uvl.dependencies.check( self, section )
259                 if not ok then
260                         section:error(err)
261                 end
262         else
263                 return false, ERR.SECT_NOTFOUND(section)
264         end
265
266         if STRICT_UNKNOWN_OPTIONS and not section:scheme('dynamic') then
267                 for k, v in pairs(section:config()) do
268                         local oo = section:option(k)
269                         if k:sub(1,1) ~= "." and not self.beenthere[oo:cid()] then
270                                 section:error(ERR.OPT_UNKNOWN(oo))
271                         end
272                 end
273         end
274
275         return section:ok(), section:errors()
276 end
277
278 function UVL._validate_option( self, option, nodeps )
279
280         self.beenthere[option:cid()] = true
281
282         if not option:scheme() and not option:parent():scheme('dynamic') then
283                 if STRICT_UNKNOWN_OPTIONS then
284                         return false, option:error(ERR.OPT_UNKNOWN(option))
285                 else
286                         return true
287                 end
288
289         elseif option:scheme() then
290                 if option:scheme('required') and not option:value() then
291                         return false, option:error(ERR.OPT_REQUIRED(option))
292
293                 elseif option:value() then
294                         local val = option:value()
295
296                         if option:scheme('type') == "reference" or
297                            option:scheme('type') == "enum"
298                         then
299                                 local scheme_values = option:scheme('values') or { }
300                                 local config_values = ( type(val) == "table" and val or { val } )
301                                 for _, v in ipairs(config_values) do
302                                         if not scheme_values[v] then
303                                                 return false, option:error( ERR.OPT_BADVALUE(
304                                                         option, { v, luci.util.serialize_data(
305                                                                 luci.util.keys(scheme_values)
306                                                         ) }
307                                                 ) )
308                                         end
309                                 end
310                         elseif option:scheme('type') == "list" then
311                                 if type(val) ~= "table" and STRICT_LIST_TYPE then
312                                         return false, option:error(ERR.OPT_NOTLIST(option))
313                                 end
314                         end
315
316                         if option:scheme('datatype') then
317                                 local dt = option:scheme('datatype')
318
319                                 if self.datatypes[dt] then
320                                         val = ( type(val) == "table" and val or { val } )
321                                         for i, v in ipairs(val) do
322                                                 if not self.datatypes[dt]( v ) then
323                                                         return false, option:error(
324                                                                 ERR.OPT_INVVALUE(option, { v, dt })
325                                                         )
326                                                 end
327                                         end
328                                 else
329                                         return false, option:error(ERR.OPT_DATATYPE(option, dt))
330                                 end
331                         end
332                 end
333
334                 if not nodeps then
335                         local ok, err = luci.uvl.dependencies.check( self, option )
336                         if not ok then
337                                 option:error(err)
338                         end
339                 end
340
341                 local ok, err = luci.uvl.validation.check( self, option )
342                 if not ok and STRICT_EXTERNAL_VALIDATORS then
343                         return false, option:error(err)
344                 end
345         end
346
347         return option:ok(), option:errors()
348 end
349
350 --- Find all parts of given scheme and construct validation tree.
351 -- This is normally done on demand, so you don't have to call this function
352 -- by yourself.
353 -- @param scheme        Name of the scheme to parse
354 -- @param alias         Create an alias for the loaded scheme
355 function UVL.read_scheme( self, scheme, alias )
356
357         local so = luci.uvl.scheme( self, scheme )
358         local bc = "%s/bytecode/%s.lua" %{ self.schemedir, scheme }
359
360         if not luci.fs.access(bc) then
361                 local schemes = { }
362                 local files = luci.fs.glob(self.schemedir .. '/*/' .. scheme)
363
364                 if files then
365                         for i, file in ipairs( files ) do
366                                 if not luci.fs.access(file) then
367                                         return false, so:error(ERR.SME_READ(so,file))
368                                 end
369
370                                 local uci = luci.model.uci.cursor( luci.fs.dirname(file), default_savedir )
371
372                                 local sd, err = uci:get_all( luci.fs.basename(file) )
373
374                                 if not sd then
375                                         return false, ERR.UCILOAD(so, err)
376                                 end
377
378                                 table.insert( schemes, sd )
379                         end
380
381                         local ok, err = self:_read_scheme_parts( so, schemes )
382                         if ok and alias then self.packages[alias] = self.packages[scheme] end
383                         return ok, err
384                 else
385                         return false, so:error(ERR.SME_FIND(so, self.schemedir))
386                 end
387         else
388                 local sc = loadfile(bc)
389                 if sc then
390                         self.packages[scheme] = sc()
391                         return true
392                 else
393                         return false, so:error(ERR.SME_READ(so,bc))
394                 end
395         end
396 end
397
398 -- Process all given parts and construct validation tree
399 function UVL._read_scheme_parts( self, scheme, schemes )
400
401         -- helper function to check for required fields
402         local function _req( t, n, c, r )
403                 for i, v in ipairs(r) do
404                         if not c[v] then
405                                 local p, o = scheme:sid(), nil
406
407                                 if t == TYPE_SECTION then
408                                         o = section( scheme, nil, p, n )
409                                 elseif t == TYPE_OPTION then
410                                         o = option( scheme, nil, p, '(nil)', n )
411                                 elseif t == TYPE_ENUM then
412                                         o = enum( scheme, nil, p, '(nil)', '(nil)', n )
413                                 end
414
415                                 return false, ERR.SME_REQFLD(o,v)
416                         end
417                 end
418                 return true
419         end
420
421         -- helper function to validate references
422         local function _ref( c, t )
423                 local k, n
424                 if c == TYPE_SECTION then
425                         k = "package"
426                         n = 1
427                 elseif c == TYPE_OPTION then
428                         k = "section"
429                         n = 2
430                 elseif c == TYPE_ENUM then
431                         k = "variable"
432                         n = 3
433                 end
434
435                 local r = luci.util.split( t[k], "." )
436                 r[1] = ( #r[1] > 0 and r[1] or scheme:sid() )
437
438                 if #r ~= n then
439                         return false, ERR.SME_BADREF(scheme, k)
440                 end
441
442                 return r
443         end
444
445         -- helper function to read bools
446         local function _bool( v )
447                 return ( v == "true" or v == "yes" or v == "on" or v == "1" )
448         end
449
450
451         local ok, err
452
453         -- Step 0: get package meta information
454         for i, conf in ipairs( schemes ) do
455                 for k, v in pairs( conf ) do
456                         if v['.type'] == 'package' then
457                                 self.packages[scheme:sid()] =
458                                         self.packages[scheme:sid()] or {
459                                                 ["name"]      = scheme:sid();
460                                                 ["sections"]  = { };
461                                                 ["variables"] = { };
462                                         }
463
464                                 for k, v2 in pairs(v) do
465                                         if k == "title" or k == "description" then
466                                                 self.packages[scheme:sid()][k] = v2
467                                         end
468                                 end
469                         end
470                 end
471         end
472
473         -- Step 1: get all sections
474         for i, conf in ipairs( schemes ) do
475                 for k, v in pairs( conf ) do
476                         if v['.type'] == 'section' then
477
478                                 ok, err = _req( TYPE_SECTION, k, v, { "name", "package" } )
479                                 if err then return false, scheme:error(err) end
480
481                                 local r, err = _ref( TYPE_SECTION, v )
482                                 if err then return false, scheme:error(err) end
483
484                                 self.packages[r[1]] =
485                                         self.packages[r[1]] or {
486                                                 ["name"]      = r[1];
487                                                 ["sections"]  = { };
488                                                 ["variables"] = { };
489                                         }
490
491                                 local p = self.packages[r[1]]
492                                           p.sections[v.name]  = p.sections[v.name]  or { }
493                                           p.variables[v.name] = p.variables[v.name] or { }
494
495                                 local s  = p.sections[v.name]
496                                 local so = scheme:section(v.name)
497
498                                 for k, v2 in pairs(v) do
499                                         if k ~= "name" and k ~= "package" and k:sub(1,1) ~= "." then
500                                                 if k == "depends" then
501                                                         s.depends = self:_read_dependency( v2, s.depends )
502                                                         if not s.depends then
503                                                                 return false, scheme:error(
504                                                                         ERR.SME_BADDEP(so, luci.util.serialize_data(s.depends))
505                                                                 )
506                                                         end
507                                                 elseif k == "dynamic" or k == "unique" or
508                                                        k == "required" or k == "named"
509                                                 then
510                                                         s[k] = _bool(v2)
511                                                 else
512                                                         s[k] = v2
513                                                 end
514                                         end
515                                 end
516
517                                 s.dynamic  = s.dynamic  or false
518                                 s.unique   = s.unique   or false
519                                 s.required = s.required or false
520                                 s.named    = s.named    or false
521                         end
522                 end
523         end
524
525         -- Step 2: get all variables
526         for i, conf in ipairs( schemes ) do
527                 for k, v in pairs( conf ) do
528                         if v['.type'] == "variable" then
529
530                                 ok, err = _req( TYPE_OPTION, k, v, { "name", "section" } )
531                                 if err then return false, scheme:error(err) end
532
533                                 local r, err = _ref( TYPE_OPTION, v )
534                                 if err then return false, scheme:error(err) end
535
536                                 local p = self.packages[r[1]]
537                                 if not p then
538                                         return false, scheme:error(
539                                                 ERR.SME_VBADPACK({scheme:sid(), '', v.name}, r[1])
540                                         )
541                                 end
542
543                                 local s = p.variables[r[2]]
544                                 if not s then
545                                         return false, scheme:error(
546                                                 ERR.SME_VBADSECT({scheme:sid(), '', v.name}, r[2])
547                                         )
548                                 end
549
550                                 s[v.name] = s[v.name] or { }
551
552                                 local t  = s[v.name]
553                                 local so = scheme:section(r[2])
554                                 local to = so:option(v.name)
555
556                                 for k, v2 in pairs(v) do
557                                         if k ~= "name" and k ~= "section" and k:sub(1,1) ~= "." then
558                                                 if k == "depends" then
559                                                         t.depends = self:_read_dependency( v2, t.depends )
560                                                         if not t.depends then
561                                                                 return false, scheme:error(so:error(
562                                                                         ERR.SME_BADDEP(to, luci.util.serialize_data(v2))
563                                                                 ))
564                                                         end
565                                                 elseif k == "validator" then
566                                                         t.validators = self:_read_validator( v2, t.validators )
567                                                         if not t.validators then
568                                                                 return false, scheme:error(so:error(
569                                                                         ERR.SME_BADVAL(to, luci.util.serialize_data(v2))
570                                                                 ))
571                                                         end
572                                                 elseif k == "valueof" then
573                                                         local values, err = self:_read_reference( v2 )
574                                                         if err then
575                                                                 return false, scheme:error(so:error(
576                                                                         ERR.REFERENCE(to, luci.util.serialize_data(v2)):child(err)
577                                                                 ))
578                                                         end
579                                                         t.type   = "reference"
580                                                         t.values = values
581                                                 elseif k == "required" then
582                                                         t[k] = _bool(v2)
583                                                 else
584                                                         t[k] = t[k] or v2
585                                                 end
586                                         end
587                                 end
588
589                                 t.type     = t.type     or "variable"
590                                 t.datatype = t.datatype or "string"
591                                 t.required = t.required or false
592                         end
593                 end
594         end
595
596         -- Step 3: get all enums
597         for i, conf in ipairs( schemes ) do
598                 for k, v in pairs( conf ) do
599                         if v['.type'] == "enum" then
600
601                                 ok, err = _req( TYPE_ENUM, k, v, { "value", "variable" } )
602                                 if err then return false, scheme:error(err) end
603
604                                 local r, err = _ref( TYPE_ENUM, v )
605                                 if err then return false, scheme:error(err) end
606
607                                 local p = self.packages[r[1]]
608                                 if not p then
609                                         return false, scheme:error(
610                                                 ERR.SME_EBADPACK({scheme:sid(), '', '', v.value}, r[1])
611                                         )
612                                 end
613
614                                 local s = p.variables[r[2]]
615                                 if not s then
616                                         return false, scheme:error(
617                                                 ERR.SME_EBADSECT({scheme:sid(), '', '', v.value}, r[2])
618                                         )
619                                 end
620
621                                 local t = s[r[3]]
622                                 if not t then
623                                         return false, scheme:error(
624                                                 ERR.SME_EBADOPT({scheme:sid(), '', '', v.value}, r[3])
625                                         )
626                                 end
627
628
629                                 local so = scheme:section(r[2])
630                                 local oo = so:option(r[3])
631                                 local eo = oo:enum(v.value)
632
633                                 if t.type ~= "enum" and t.type ~= "reference" then
634                                         return false, scheme:error(ERR.SME_EBADTYPE(eo))
635                                 end
636
637                                 if not t.values then
638                                         t.values = { [v.value] = v.title or v.value }
639                                 else
640                                         t.values[v.value] = v.title or v.value
641                                 end
642
643                                 if not t.enum_depends then
644                                         t.enum_depends = { }
645                                 end
646
647                                 if v.default then
648                                         if t.default then
649                                                 return false, scheme:error(ERR.SME_EBADDEF(eo))
650                                         end
651                                         t.default = v.value
652                                 end
653
654                                 if v.depends then
655                                         t.enum_depends[v.value] = self:_read_dependency(
656                                                 v.depends, t.enum_depends[v.value]
657                                         )
658
659                                         if not t.enum_depends[v.value] then
660                                                 return false, scheme:error(so:error(oo:error(
661                                                         ERR.SME_BADDEP(eo, luci.util.serialize_data(v.depends))
662                                                 )))
663                                         end
664                                 end
665                         end
666                 end
667         end
668
669         return self
670 end
671
672 -- Read a dependency specification
673 function UVL._read_dependency( self, values, deps )
674         local expr = "%$?[a-zA-Z0-9_]+"
675         if values then
676                 values = ( type(values) == "table" and values or { values } )
677                 for _, value in ipairs(values) do
678                         local parts     = luci.util.split( value, "%s*,%s*", nil, true )
679                         local condition = { }
680                         for i, val in ipairs(parts) do
681                                 local k, v = unpack(luci.util.split(val, "%s*=%s*", nil, true))
682
683                                 if k and (
684                                         k:match("^"..expr.."%."..expr.."%."..expr.."$") or
685                                         k:match("^"..expr.."%."..expr.."$") or
686                                         k:match("^"..expr.."$")
687                                 ) then
688                                         condition[k] = v or true
689                                 else
690                                         return nil
691                                 end
692                         end
693
694                         if not deps then
695                                 deps = { condition }
696                         else
697                                 table.insert( deps, condition )
698                         end
699                 end
700         end
701
702         return deps
703 end
704
705 -- Read a validator specification
706 function UVL._read_validator( self, values, validators )
707         if values then
708                 values = ( type(values) == "table" and values or { values } )
709                 for _, value in ipairs(values) do
710                         local validator
711
712                         if value:match("^exec:") then
713                                 validator = value:gsub("^exec:","")
714                         elseif value:match("^lua:") then
715                                 validator = self:_resolve_function( (value:gsub("^lua:","") ) )
716                         elseif value:match("^regexp:") then
717                                 local pattern = value:gsub("^regexp:","")
718                                 validator = function( type, dtype, pack, sect, optn, ... )
719                                         local values = { ... }
720                                         for _, v in ipairs(values) do
721                                                 local ok, match =
722                                                         luci.util.copcall( string.match, v, pattern )
723
724                                                 if not ok then
725                                                         return false, match
726                                                 elseif not match then
727                                                         return false,
728                                                                 'Value "%s" does not match pattern "%s"' % {
729                                                                         v, pattern
730                                                                 }
731                                                 end
732                                         end
733                                         return true
734                                 end
735                         end
736
737                         if validator then
738                                 if not validators then
739                                         validators = { validator }
740                                 else
741                                         table.insert( validators, validator )
742                                 end
743                         else
744                                 return nil
745                         end
746                 end
747
748                 return validators
749         end
750 end
751
752 -- Read a reference specification (XXX: We should validate external configs too...)
753 function UVL._read_reference( self, values )
754         local val = { }
755         values = ( type(values) == "table" and values or { values } )
756
757         for _, value in ipairs(values) do
758                 local ref = luci.util.split(value, ".")
759
760                 if #ref == 2 or #ref == 3 then
761                         local co = luci.uvl.config( self, ref[1] )
762                         if not co:config() then return false, co:errors() end
763
764                         for k, v in pairs(co:config()) do
765                                 if v['.type'] == ref[2] then
766                                         if #ref == 2 then
767                                                 if v['.anonymous'] == true then
768                                                         return false, ERR.SME_INVREF('', value)
769                                                 end
770                                                 val[k] = k      -- XXX: title/description would be nice
771                                         elseif v[ref[3]] then
772                                                 val[v[ref[3]]] = v[ref[3]]  -- XXX: dito
773                                         end
774                                 end
775                         end
776                 else
777                         return false, ERR.SME_BADREF('', value)
778                 end
779         end
780
781         return val, nil
782 end
783
784 -- Resolve given path
785 function UVL._resolve_function( self, value )
786         local path = luci.util.split(value, ".")
787
788         for i=1, #path-1 do
789                 local stat, mod = luci.util.copcall(
790                         require, table.concat(path, ".", 1, i)
791                 )
792
793                 if stat and mod then
794                         for j=i+1, #path-1 do
795                                 if not type(mod) == "table" then
796                                         break
797                                 end
798                                 mod = mod[path[j]]
799                                 if not mod then
800                                         break
801                                 end
802                         end
803                         mod = type(mod) == "table" and mod[path[#path]] or nil
804                         if type(mod) == "function" then
805                                 return mod
806                         end
807                 end
808         end
809 end
810
811
812 --- Object representation of an uvl item - base class.
813 uvlitem = luci.util.class()
814
815 function uvlitem.cid(self)
816         return table.concat( self.cref, '.' )
817 end
818
819 function uvlitem.sid(self)
820         return table.concat( self.sref, '.' )
821 end
822
823 function uvlitem.scheme(self, opt)
824         local s
825
826         if #self.sref == 4 or #self.sref == 3 then
827                 s = self.s and self.s.packages
828                 s = s      and s[self.sref[1]]
829                 s = s      and s.variables
830                 s = s      and s[self.sref[2]]
831                 s = s      and s[self.sref[3]]
832         elseif #self.sref == 2 then
833                 s = self.s and self.s.packages
834                 s = s      and s[self.sref[1]]
835                 s = s      and s.sections
836                 s = s      and s[self.sref[2]]
837         else
838                 s = self.s and self.s.packages
839                 s = s      and s[self.sref[1]]
840         end
841
842         if s and opt then
843                 return s[opt]
844         elseif s then
845                 return s
846         end
847 end
848
849 function uvlitem.config(self, opt)
850         local c
851
852         if #self.cref == 4 or #self.cref == 3 then
853                 c = self.c and self.c[self.cref[2]] or nil
854                 c = c      and c[self.cref[3]]      or nil
855         elseif #self.cref == 2 then
856                 c = self.c and self.c[self.cref[2]] or nil
857         else
858                 c = self.c
859         end
860
861         if c and opt then
862                 return c[opt]
863         elseif c then
864                 return c
865         end
866 end
867
868 function uvlitem.title(self)
869         return self:scheme() and self:scheme('title') or
870                 self.cref[3] or self.cref[2] or self.cref[1]
871 end
872
873 function uvlitem.type(self)
874         if self.t == luci.uvl.TYPE_CONFIG then
875                 return 'config'
876         elseif self.t == luci.uvl.TYPE_SECTION then
877                 return 'section'
878         elseif self.t == luci.uvl.TYPE_OPTION then
879                 return 'option'
880         elseif self.t == luci.uvl.TYPE_ENUM then
881                 return 'enum'
882         end
883 end
884
885 function uvlitem.error(self, ...)
886         if not self.e then
887                 local errconst = { ERR.CONFIG, ERR.SECTION, ERR.OPTION, ERR.OPTION }
888                 self.e = errconst[#self.cref]( self )
889         end
890
891         return self.e:child( ... )
892 end
893
894 function uvlitem.errors(self)
895         return self.e
896 end
897
898 function uvlitem.ok(self)
899         return not self:errors()
900 end
901
902 function uvlitem.parent(self)
903         if self.p then
904                 return self.p
905         elseif #self.cref == 3 or #self.cref == 4 then
906                 return luci.uvl.section( self.s, self.c, self.cref[1], self.cref[2] )
907         elseif #self.cref == 2 then
908                 return luci.uvl.config( self.s, self.c, self.cref[1] )
909         else
910                 return nil
911         end
912 end
913
914 function uvlitem._loadconf(self, co, c)
915         if not co then
916                 local uci, err = luci.model.uci.cursor(), nil
917                 co, err = uci:get_all(c)
918
919                 if err then
920                         self:error(ERR.UCILOAD(self, err))
921                 end
922         end
923         return co
924 end
925
926
927 --- Object representation of a scheme.
928 -- @class       scheme
929 -- @cstyle      instance
930 -- @name        luci.uvl.scheme
931
932 --- Scheme instance constructor.
933 -- @class                       function
934 -- @name                        scheme
935 -- @param scheme        Scheme instance
936 -- @param co            Configuration data
937 -- @param c                     Configuration name
938 -- @return                      Config instance
939 scheme = luci.util.class(uvlitem)
940
941 function scheme.__init__(self, scheme, co, c)
942         if not c then
943                 c, co = co, nil
944         end
945
946         self.cref = { c }
947         self.sref = { c }
948         self.c    = self:_loadconf(co, c)
949         self.s    = scheme
950         self.t    = luci.uvl.TYPE_SCHEME
951 end
952
953 --- Add an error to scheme.
954 -- @return      Scheme error context
955 function scheme.error(self, ...)
956         if not self.e then self.e = ERR.SCHEME( self ) end
957         return self.e:child( ... )
958 end
959
960 --- Get an associated config object.
961 -- @return      Config instance
962 function scheme.config(self)
963         local co = luci.uvl.config( self.s, self.cref[1] )
964               co.p = self
965
966         return co
967 end
968
969 --- Get all section objects associated with this scheme.
970 -- @return      Table containing all associated luci.uvl.section instances
971 function scheme.sections(self)
972         local v = { }
973         if self.s.packages[self.sref[1]].sections then
974                 for o, _ in pairs( self.s.packages[self.sref[1]].sections ) do
975                         table.insert( v, luci.uvl.option(
976                                 self.s, self.c, self.cref[1], self.cref[2], o
977                         ) )
978                 end
979         end
980         return v
981 end
982
983 --- Get an associated section object.
984 -- @param s     Section to select
985 -- @return      Section instance
986 function scheme.section(self, s)
987         local so = luci.uvl.section( self.s, self.c, self.cref[1], s )
988               so.p = self
989
990         return so
991 end
992
993
994 --- Object representation of a config.
995 -- @class       config
996 -- @cstyle      instance
997 -- @name        luci.uvl.config
998
999 --- Config instance constructor.
1000 -- @class                       function
1001 -- @name                        config
1002 -- @param scheme        Scheme instance
1003 -- @param co            Configuration data
1004 -- @param c                     Configuration name
1005 -- @return                      Config instance
1006 config = luci.util.class(uvlitem)
1007
1008 function config.__init__(self, scheme, co, c)
1009         if not c then
1010                 c, co = co, nil
1011         end
1012
1013         self.cref = { c }
1014         self.sref = { c }
1015         self.c    = self:_loadconf(co, c)
1016         self.s    = scheme
1017         self.t    = luci.uvl.TYPE_CONFIG
1018 end
1019
1020 --- Get all section objects associated with this config.
1021 -- @return      Table containing all associated luci.uvl.section instances
1022 function config.sections(self)
1023         local v = { }
1024         if self.s.packages[self.sref[1]].sections then
1025                 for o, _ in pairs( self.s.packages[self.sref[1]].sections ) do
1026                         table.insert( v, luci.uvl.option(
1027                                 self.s, self.c, self.cref[1], self.cref[2], o
1028                         ) )
1029                 end
1030         end
1031         return v
1032 end
1033
1034 --- Get an associated section object.
1035 -- @param s     Section to select
1036 -- @return      Section instance
1037 function config.section(self, s)
1038         local so = luci.uvl.section( self.s, self.c, self.cref[1], s )
1039               so.p = self
1040
1041         return so
1042 end
1043
1044
1045 --- Object representation of a scheme/config section.
1046 -- @class       module
1047 -- @cstyle      instance
1048 -- @name        luci.uvl.section
1049
1050 --- Section instance constructor.
1051 -- @class                       function
1052 -- @name                        section
1053 -- @param scheme        Scheme instance
1054 -- @param co            Configuration data
1055 -- @param c                     Configuration name
1056 -- @param s                     Section name
1057 -- @return                      Section instance
1058 section = luci.util.class(uvlitem)
1059
1060 function section.__init__(self, scheme, co, c, s)
1061         self.cref = { c, s }
1062         self.sref = { c, co and co[s] and co[s]['.type'] or s }
1063         self.c    = self:_loadconf(co, c)
1064         self.s    = scheme
1065         self.t    = luci.uvl.TYPE_SECTION
1066 end
1067
1068 --- Get all option objects associated with this section.
1069 -- @return      Table containing all associated luci.uvl.option instances
1070 function section.variables(self)
1071         local v = { }
1072         if self.s.packages[self.sref[1]].variables[self.sref[2]] then
1073                 for o, _ in pairs(
1074                         self.s.packages[self.sref[1]].variables[self.sref[2]]
1075                 ) do
1076                         table.insert( v, luci.uvl.option(
1077                                 self.s, self.c, self.cref[1], self.cref[2], o
1078                         ) )
1079                 end
1080         end
1081         return v
1082 end
1083
1084 --- Get an associated option object.
1085 -- @param o     Option to select
1086 -- @return      Option instance
1087 function section.option(self, o)
1088         local oo = luci.uvl.option( self.s, self.c, self.cref[1], self.cref[2], o )
1089               oo.p = self
1090
1091         return oo
1092 end
1093
1094
1095 --- Object representation of a scheme/config option.
1096 -- @class       module
1097 -- @cstyle      instance
1098 -- @name        luci.uvl.option
1099
1100 --- Section instance constructor.
1101 -- @class                       function
1102 -- @name                        option
1103 -- @param scheme        Scheme instance
1104 -- @param co            Configuration data
1105 -- @param c                     Configuration name
1106 -- @param s                     Section name
1107 -- @param o                     Option name
1108 -- @return                      Option instance
1109 option = luci.util.class(uvlitem)
1110
1111 function option.__init__(self, scheme, co, c, s, o)
1112         self.cref = { c, s, o }
1113         self.sref = { c, co and co[s] and co[s]['.type'] or s, o }
1114         self.c    = self:_loadconf(co, c)
1115         self.s    = scheme
1116         self.t    = luci.uvl.TYPE_OPTION
1117 end
1118
1119 --- Get the value of this option.
1120 -- @return      The associated configuration value
1121 function option.value(self)
1122         local v = self:config() or self:scheme('default')
1123         if v and self:scheme('multival') then
1124                 v = luci.util.split( v, "%s+", nil, true )
1125         end
1126         return v
1127 end
1128
1129 --- Get the associated section information in scheme.
1130 -- @return      Table containing the scheme properties
1131 function option.section(self)
1132         return self.s.packages[self.sref[1]].sections[self.sref[2]]
1133 end
1134
1135 --- Construct an enum object instance from given or default value.
1136 -- @param v     Value to select
1137 -- @return      Enum instance for selected value
1138 function option.enum(self, val)
1139         return enum(
1140                 self.s, self.c,
1141                 self.cref[1], self.cref[2], self.cref[3],
1142                 val or self:value()
1143         )
1144 end
1145
1146
1147 --- Object representation of a enum value.
1148 -- @class       module
1149 -- @cstyle      instance
1150 -- @name        luci.uvl.enum
1151
1152 --- Section instance constructor.
1153 -- @class                       function
1154 -- @name                        enum
1155 -- @param scheme        Scheme instance
1156 -- @param co            Configuration data
1157 -- @param c                     Configuration name
1158 -- @param s                     Section name
1159 -- @param o                     Enum name
1160 -- @param v                     Enum value
1161 -- @return                      Enum value instance
1162 enum = luci.util.class(option)
1163
1164 function enum.__init__(self, scheme, co, c, s, o, v)
1165         self.cref = { c, s, o, v }
1166         self.sref = { c, co and co[s] and co[s]['.type'] or s, o, v }
1167         self.c    = self:_loadconf(co, c)
1168         self.s    = scheme
1169         self.t    = luci.uvl.TYPE_ENUM
1170 end