* luci/libs: uvl: add uci error mechanism to uvl error handling
[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_VARIABLE = 0x03
37 TYPE_OPTION   = 0x04
38 TYPE_ENUM     = 0x05
39
40 --- Boolean; default true;
41 -- treat sections found in config but not in scheme as error
42 STRICT_UNKNOWN_SECTIONS    = true
43
44 --- Boolean; default true;
45 -- treat options found in config but not in scheme as error
46 STRICT_UNKNOWN_OPTIONS     = true
47
48 --- Boolean; default true;
49 -- treat failed external validators as error
50 STRICT_EXTERNAL_VALIDATORS = true
51
52 --- Boolean; default true;
53 -- treat list values stored as options like errors
54 STRICT_LIST_TYPE           = true
55
56
57 local default_schemedir = "/lib/uci/schema"
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.uci                = luci.model.uci
73         self.err                = luci.uvl.errors
74         self.dep                = luci.uvl.dependencies
75         self.datatypes  = luci.uvl.datatypes
76 end
77
78
79 --- Parse given scheme and return the scheme tree.
80 -- @param scheme        Name of the scheme to parse
81 -- @return                      Table containing the parsed scheme or nil on error
82 -- @return                      String containing the reason for errors (if any)
83 function UVL.get_scheme( self, scheme )
84         if not self.packages[scheme] then
85                 local ok, err = self:read_scheme( scheme )
86                 if not ok then
87                         return nil, err
88                 end
89         end
90         return self.packages[scheme], nil
91 end
92
93 --- Validate given configuration, section or option.
94 -- @param config        Name of the configuration to validate
95 -- @param section       Name of the section to validate (optional)
96 -- @param option        Name of the option to validate (optional)
97 -- @return                      Boolean indicating whether the given config validates
98 -- @return                      String containing the reason for errors (if any)
99 function UVL.validate( self, config, section, option )
100         if config and section and option then
101                 return self:validate_option( config, section, option )
102         elseif config and section then
103                 return self:validate_section( config, section )
104         elseif config then
105                 return self:validate_config( config )
106         end
107 end
108
109 --- Validate given configuration.
110 -- @param config        Name of the configuration to validate
111 -- @return                      Boolean indicating whether the given config validates
112 -- @return                      String containing the reason for errors (if any)
113 function UVL.validate_config( self, config, uci )
114
115         if not self.packages[config] then
116                 local ok, err = self:read_scheme(config)
117                 if not ok then
118                         return false, err
119                 end
120         end
121
122         local co = luci.uvl.config( self, uci or config, uci and config )
123         local sc = { }
124
125         self.beenthere = { }
126
127         if not co:config() then
128                 return false, co:errors()
129         end
130
131         local function _uci_foreach( type, func )
132                 for k, v in pairs(co:config()) do
133                         if v['.type'] == type then
134                                 sc[type] = sc[type] + 1
135                                 local ok, err = func( k, v )
136                                 if not ok then co:error(err) end
137                         end
138                 end
139         end
140
141         for k, v in pairs( self.packages[config].sections ) do
142                 sc[k] = 0
143                 _uci_foreach( k,
144                         function(s)
145                                 return self:_validate_section( co:section(s) )
146                         end
147                 )
148         end
149
150         if STRICT_UNKNOWN_SECTIONS then
151                 for k, v in pairs(co:config()) do
152                         local so = co:section(k)
153                         if not self.beenthere[so:cid()] then
154                                 co:error(ERR.SECT_UNKNOWN(so))
155                         end
156                 end
157         end
158
159         for _, k in ipairs(luci.util.keys(sc)) do
160                 local so = co:section(k)
161                 if so:scheme('required') and sc[k] == 0 then
162                         co:error(ERR.SECT_REQUIRED(so))
163                 elseif so:scheme('unique') and sc[k] > 1 then
164                         co:error(ERR.SECT_UNIQUE(so))
165                 end
166         end
167
168         return co:ok(), co:errors()
169 end
170
171 --- Validate given config section.
172 -- @param config        Name of the configuration to validate
173 -- @param section       Name of the section to validate
174 -- @return                      Boolean indicating whether the given config validates
175 -- @return                      String containing the reason for errors (if any)
176 function UVL.validate_section( self, config, section, uci )
177
178         if not self.packages[config] then
179                 local ok, err = self:read_scheme( config )
180                 if not ok then
181                         return false, err
182                 end
183         end
184
185         local co = luci.uvl.config( self, uci or config, uci and config )
186         local so = co:section( section )
187
188         self.beenthere = { }
189
190         if not co:config() then
191                 return false, co:errors()
192         end
193
194         if so:config() then
195                 return self:_validate_section( so )
196         else
197                 return false, ERR.SECT_NOTFOUND(so)
198         end
199 end
200
201 --- Validate given config option.
202 -- @param config        Name of the configuration to validate
203 -- @param section       Name of the section to validate
204 -- @param option        Name of the option to validate
205 -- @return                      Boolean indicating whether the given config validates
206 -- @return                      String containing the reason for errors (if any)
207 function UVL.validate_option( self, config, section, option, uci )
208
209         if not self.packages[config] then
210                 local ok, err = self:read_scheme( config )
211                 if not ok then
212                         return false, err
213                 end
214         end
215
216         local co = luci.uvl.config( self, uci or config, uci and config )
217         local so = co:section( section )
218         local oo = so:option( option )
219
220         if not co:config() then
221                 return false, co:errors()
222         end
223
224         if so:config() and oo:config() then
225                 return self:_validate_option( oo )
226         else
227                 return false, ERR.OPT_NOTFOUND(oo)
228         end
229 end
230
231
232 function UVL._validate_section( self, section )
233
234         if section:config() then
235                 if section:scheme('named') == true and
236                    section:config('.anonymous') == true
237                 then
238                         return false, ERR.SECT_NAMED(section)
239                 end
240
241                 for _, v in ipairs(section:variables()) do
242                         local ok, err = self:_validate_option( v )
243                         if not ok then
244                                 section:error(err)
245                         end
246                 end
247
248                 local ok, err = luci.uvl.dependencies.check( self, section )
249                 if not ok then
250                         section:error(err)
251                 end
252         else
253                 return false, ERR.SECT_NOTFOUND(section)
254         end
255
256         if STRICT_UNKNOWN_OPTIONS and not section:scheme('dynamic') then
257                 for k, v in pairs(section:config()) do
258                         local oo = section:option(k)
259                         if k:sub(1,1) ~= "." and not self.beenthere[oo:cid()] then
260                                 section:error(ERR.OPT_NOTFOUND(oo))
261                         end
262                 end
263         end
264
265         return section:ok(), section:errors()
266 end
267
268 function UVL._validate_option( self, option, nodeps )
269
270         if not option:scheme() and not option:parent():scheme('dynamic') then
271                 return false, option:error(ERR.OPT_UNKNOWN(option))
272
273         elseif option:scheme() then
274                 if option:scheme('required') and not option:value() then
275                         return false, option:error(ERR.OPT_REQUIRED(option))
276
277                 elseif option:value() then
278                         local val = option:value()
279
280                         if option:scheme('type') == "reference" or
281                            option:scheme('type') == "enum"
282                         then
283                                 if not option:scheme('values') or
284                                    not option:scheme('values')[val]
285                                 then
286                                         return false, option:error( ERR.OPT_BADVALUE(
287                                                 option, { val, table.concat(
288                                                         luci.util.keys(option:scheme('values') or {}), ", "
289                                                 ) }
290                                         ) )
291                                 end
292                         elseif option:scheme('type') == "list" then
293                                 if type(val) ~= "table" and STRICT_LIST_TYPE then
294                                         return false, option:error(ERR.OPT_NOTLIST(option))
295                                 end
296                         elseif option:scheme('datatype') then
297                                 local dt = option:scheme('datatype')
298
299                                 if self.datatypes[dt] then
300                                         val = ( type(val) == "table" and val or { val } )
301                                         for i, v in ipairs(val) do
302                                                 if not self.datatypes[dt]( v ) then
303                                                         return false, option:error(
304                                                                 ERR.OPT_INVVALUE(option, {v, dt})
305                                                         )
306                                                 end
307                                         end
308                                 else
309                                         return false, option:error(ERR.OPT_DATATYPE(option, dt))
310                                 end
311                         end
312                 end
313
314                 if not nodeps then
315                         local ok, err = luci.uvl.dependencies.check( self, option )
316                         if not ok then
317                                 option:error(err)
318                         end
319                 end
320
321                 local ok, err = luci.uvl.validation.check( self, option )
322                 if not ok and STRICT_EXTERNAL_VALIDATORS then
323                         return false, option:error(err)
324                 end
325         end
326
327         return option:ok(), option:errors()
328 end
329
330 --- Find all parts of given scheme and construct validation tree.
331 -- This is normally done on demand, so you don't have to call this function
332 -- by yourself.
333 -- @param scheme        Name of the scheme to parse
334 function UVL.read_scheme( self, scheme )
335
336         local so = luci.uvl.scheme( self, scheme )
337
338         local schemes = { }
339         local files = luci.fs.glob(self.schemedir .. '/*/' .. scheme)
340
341         if files then
342                 for i, file in ipairs( files ) do
343                         if not luci.fs.access(file) then
344                                 return so:error(ERR.SME_READ(so,file))
345                         end
346
347                         local uci = luci.model.uci.cursor()
348                               uci:set_confdir( luci.fs.dirname(file) )
349
350                         local sd, err = uci:get_all( luci.fs.basename(file) )
351
352                         if not sd then
353                                 return false, ERR.UCILOAD(so, err)
354                         end
355
356                         table.insert( schemes, sd )
357                 end
358
359                 return self:_read_scheme_parts( so, schemes )
360         else
361                 return false, so:error(ERR.SME_FIND(so, self.schemedir))
362         end
363 end
364
365 -- Process all given parts and construct validation tree
366 function UVL._read_scheme_parts( self, scheme, schemes )
367
368         -- helper function to check for required fields
369         local function _req( c, t, r )
370                 for i, v in ipairs(r) do
371                         if not t[v] then
372                                 return false, ERR.SME_REQFLD({c,t}, v)
373                         end
374                 end
375                 return true
376         end
377
378         -- helper function to validate references
379         local function _ref( c, t )
380                 local k, n
381                 if c == TYPE_SECTION then
382                         k = "package"
383                         n = 1
384                 elseif c == TYPE_VARIABLE then
385                         k = "section"
386                         n = 2
387                 elseif c == TYPE_ENUM then
388                         k = "variable"
389                         n = 3
390                 end
391
392                 local r = luci.util.split( t[k], "." )
393                 r[1] = ( #r[1] > 0 and r[1] or scheme:sid() )
394
395                 if #r ~= n then
396                         return false, ERR.SME_BADREF(scheme, k)
397                 end
398
399                 return r
400         end
401
402         -- helper function to read bools
403         local function _bool( v )
404                 return ( v == "true" or v == "yes" or v == "on" or v == "1" )
405         end
406
407
408         local ok, err
409
410         -- Step 1: get all sections
411         for i, conf in ipairs( schemes ) do
412                 for k, v in pairs( conf ) do
413                         if v['.type'] == 'section' then
414
415                                 ok, err = _req( TYPE_SECTION, v, { "name", "package" } )
416                                 if err then return false, scheme:error(err) end
417
418                                 local r, err = _ref( TYPE_SECTION, v )
419                                 if err then return false, scheme:error(err) end
420
421                                 self.packages[r[1]] =
422                                         self.packages[r[1]] or {
423                                                 ["name"]      = r[1];
424                                                 ["sections"]  = { };
425                                                 ["variables"] = { };
426                                         }
427
428                                 local p = self.packages[r[1]]
429                                           p.sections[v.name]  = p.sections[v.name]  or { }
430                                           p.variables[v.name] = p.variables[v.name] or { }
431
432                                 local s  = p.sections[v.name]
433                                 local so = scheme:section(v.name)
434
435                                 for k, v2 in pairs(v) do
436                                         if k ~= "name" and k ~= "package" and k:sub(1,1) ~= "." then
437                                                 if k == "depends" then
438                                                         s.depends = self:_read_dependency( v2, s.depends )
439                                                         if not s.depends then
440                                                                 return false, scheme:error(
441                                                                         ERR.SME_BADDEP(so, luci.util.serialize_data(s.depends))
442                                                                 )
443                                                         end
444                                                 elseif k == "dynamic" or k == "unique" or
445                                                        k == "required" or k == "named"
446                                                 then
447                                                         s[k] = _bool(v2)
448                                                 else
449                                                         s[k] = v2
450                                                 end
451                                         end
452                                 end
453
454                                 s.dynamic  = s.dynamic  or false
455                                 s.unique   = s.unique   or false
456                                 s.required = s.required or false
457                                 s.named    = s.named    or false
458                         end
459                 end
460         end
461
462         -- Step 2: get all variables
463         for i, conf in ipairs( schemes ) do
464                 for k, v in pairs( conf ) do
465                         if v['.type'] == "variable" then
466
467                                 ok, err = _req( TYPE_VARIABLE, v, { "name", "section" } )
468                                 if err then return false, scheme:error(err) end
469
470                                 local r, err = _ref( TYPE_VARIABLE, v )
471                                 if err then return false, scheme:error(err) end
472
473                                 local p = self.packages[r[1]]
474                                 if not p then
475                                         return false, scheme:error(
476                                                 ERR.SME_VBADPACK({scheme:sid(), '', v.name}, r[1])
477                                         )
478                                 end
479
480                                 local s = p.variables[r[2]]
481                                 if not s then
482                                         return false, scheme:error(
483                                                 ERR.SME_VBADSECT({scheme:sid(), '', v.name}, r[2])
484                                         )
485                                 end
486
487                                 s[v.name] = s[v.name] or { }
488
489                                 local t  = s[v.name]
490                                 local so = scheme:section(r[2])
491                                 local to = so:option(v.name)
492
493                                 for k, v2 in pairs(v) do
494                                         if k ~= "name" and k ~= "section" and k:sub(1,1) ~= "." then
495                                                 if k == "depends" then
496                                                         t.depends = self:_read_dependency( v2, t.depends )
497                                                         if not t.depends then
498                                                                 return false, scheme:error(so:error(
499                                                                         ERR.SME_BADDEP(to, luci.util.serialize_data(v2))
500                                                                 ))
501                                                         end
502                                                 elseif k == "validator" then
503                                                         t.validators = self:_read_validator( v2, t.validators )
504                                                         if not t.validators then
505                                                                 return false, scheme:error(so:error(
506                                                                         ERR.SME_BADVAL(to, luci.util.serialize_data(v2))
507                                                                 ))
508                                                         end
509                                                 elseif k == "valueof" then
510                                                         local values, err = self:_read_reference( v2 )
511                                                         if err then
512                                                                 return false, scheme:error(so:error(
513                                                                         ERR.REFERENCE(to, luci.util.serialize_data(v2)):child(err)
514                                                                 ))
515                                                         end
516                                                         t.type   = "reference"
517                                                         t.values = values
518                                                 elseif k == "required" then
519                                                         t[k] = _bool(v2)
520                                                 else
521                                                         t[k] = t[k] or v2
522                                                 end
523                                         end
524                                 end
525
526                                 t.type     = t.type     or "variable"
527                                 t.datatype = t.datatype or "string"
528                                 t.required = t.required or false
529                         end
530                 end
531         end
532
533         -- Step 3: get all enums
534         for i, conf in ipairs( schemes ) do
535                 for k, v in pairs( conf ) do
536                         if v['.type'] == "enum" then
537
538                                 ok, err = _req( TYPE_ENUM, v, { "value", "variable" } )
539                                 if err then return false, scheme:error(err) end
540
541                                 local r, err = _ref( TYPE_ENUM, v )
542                                 if err then return false, scheme:error(err) end
543
544                                 local p = self.packages[r[1]]
545                                 if not p then
546                                         return false, scheme:error(
547                                                 ERR.SME_EBADPACK({scheme:sid(), '', '', v.value}, r[1])
548                                         )
549                                 end
550
551                                 local s = p.variables[r[2]]
552                                 if not s then
553                                         return false, scheme:error(
554                                                 ERR.SME_EBADSECT({scheme:sid(), '', '', v.value}, r[2])
555                                         )
556                                 end
557
558                                 local t = s[r[3]]
559                                 if not t then
560                                         return false, scheme:error(
561                                                 ERR.SME_EBADOPT({scheme:sid(), '', '', v.value}, r[3])
562                                         )
563                                 end
564
565
566                                 local so = scheme:section(r[2])
567                                 local oo = so:option(r[3])
568                                 local eo = oo:enum(v.value)
569
570                                 if t.type ~= "enum" then
571                                         return false, scheme:error(ERR.SME_EBADTYPE(eo))
572                                 end
573
574                                 if not t.values then
575                                         t.values = { [v.value] = v.title or v.value }
576                                 else
577                                         t.values[v.value] = v.title or v.value
578                                 end
579
580                                 if not t.enum_depends then
581                                         t.enum_depends = { }
582                                 end
583
584                                 if v.default then
585                                         if t.default then
586                                                 return false, scheme:error(ERR.SME_EBADDEF(eo))
587                                         end
588                                         t.default = v.value
589                                 end
590
591                                 if v.depends then
592                                         t.enum_depends[v.value] = self:_read_dependency(
593                                                 v.depends, t.enum_depends[v.value]
594                                         )
595
596                                         if not t.enum_depends[v.value] then
597                                                 return false, scheme:error(so:error(oo:error(
598                                                         ERR.SME_BADDEP(eo, luci.util.serialize_data(v.depends))
599                                                 )))
600                                         end
601                                 end
602                         end
603                 end
604         end
605
606         return self
607 end
608
609 -- Read a dependency specification
610 function UVL._read_dependency( self, values, deps )
611         local expr = "%$?[a-zA-Z0-9_]+"
612         if values then
613                 values = ( type(values) == "table" and values or { values } )
614                 for _, value in ipairs(values) do
615                         local parts     = luci.util.split( value, "%s*,%s*", nil, true )
616                         local condition = { }
617                         for i, val in ipairs(parts) do
618                                 local k, v = unpack(luci.util.split(val, "%s*=%s*", nil, true))
619
620                                 if k and (
621                                         k:match("^"..expr.."%."..expr.."%."..expr.."$") or
622                                         k:match("^"..expr.."%."..expr.."$") or
623                                         k:match("^"..expr.."$")
624                                 ) then
625                                         condition[k] = v or true
626                                 else
627                                         return nil
628                                 end
629                         end
630
631                         if not deps then
632                                 deps = { condition }
633                         else
634                                 table.insert( deps, condition )
635                         end
636                 end
637         end
638
639         return deps
640 end
641
642 -- Read a validator specification
643 function UVL._read_validator( self, values, validators )
644         if values then
645                 values = ( type(values) == "table" and values or { values } )
646                 for _, value in ipairs(values) do
647                         local validator
648
649                         if value:match("^exec:") then
650                                 validator = value:gsub("^exec:","")
651                         elseif value:match("^lua:") then
652                                 validator = self:_resolve_function( (value:gsub("^lua:","") ) )
653                         end
654
655                         if validator then
656                                 if not validators then
657                                         validators = { validator }
658                                 else
659                                         table.insert( validators, validator )
660                                 end
661                         else
662                                 return nil
663                         end
664                 end
665
666                 return validators
667         end
668 end
669
670 -- Read a reference specification (XXX: We should validate external configs too...)
671 function UVL._read_reference( self, values )
672         local val = { }
673         values = ( type(values) == "table" and values or { values } )
674
675         for _, value in ipairs(values) do
676                 local ref = luci.util.split(value, ".")
677
678                 if #ref == 2 or #ref == 3 then
679                         local co = luci.uvl.config( self, ref[1] )
680                         if not co:config() then return false, co:errors() end
681
682                         for k, v in pairs(co:config()) do
683                                 if v['.type'] == ref[2] then
684                                         if #ref == 2 then
685                                                 if v['.anonymous'] == true then
686                                                         return false, ERR.SME_INVREF('', value)
687                                                 end
688                                                 val[k] = k      -- XXX: title/description would be nice
689                                         elseif v[ref[3]] then
690                                                 val[v[ref[3]]] = v[ref[3]]  -- XXX: dito
691                                         end
692                                 end
693                         end
694                 else
695                         return false, ERR.SME_BADREF('', value)
696                 end
697         end
698
699         return val, nil
700 end
701
702 -- Resolve given path
703 function UVL._resolve_function( self, value )
704         local path = luci.util.split(value, ".")
705
706         for i=1, #path-1 do
707                 local stat, mod = luci.util.copcall(
708                         require, table.concat(path, ".", 1, i)
709                 )
710
711                 if stat and mod then
712                         for j=i+1, #path-1 do
713                                 if not type(mod) == "table" then
714                                         break
715                                 end
716                                 mod = mod[path[j]]
717                                 if not mod then
718                                         break
719                                 end
720                         end
721                         mod = type(mod) == "table" and mod[path[#path]] or nil
722                         if type(mod) == "function" then
723                                 return mod
724                         end
725                 end
726         end
727 end
728
729
730 --- Object representation of an uvl item - base class.
731 uvlitem = luci.util.class()
732
733 function uvlitem.cid(self)
734         return table.concat( self.cref, '.' )
735 end
736
737 function uvlitem.sid(self)
738         return table.concat( self.sref, '.' )
739 end
740
741 function uvlitem.scheme(self, opt)
742         local s
743
744         if #self.sref == 4 or #self.sref == 3 then
745                 s = self.s
746                         .packages[self.sref[1]]
747                         .variables[self.sref[2]][self.sref[3]]
748         elseif #self.sref == 2 then
749                 s = self.s
750                         .packages[self.sref[1]]
751                         .sections[self.sref[2]]
752         else
753                 s = self.s
754                         .packages[self.sref[1]]
755         end
756
757         if s and opt then
758                 return s[opt]
759         elseif s then
760                 return s
761         end
762 end
763
764 function uvlitem.config(self, opt)
765         local c
766
767         if #self.cref == 4 or #self.cref == 3 then
768                 c = self.c[self.cref[2]][self.cref[3]]
769         elseif #self.cref == 2 then
770                 c = self.c[self.cref[2]]
771         else
772                 c = self.c
773         end
774
775         if c and opt then
776                 return c[opt]
777         elseif c then
778                 return c
779         end
780 end
781
782 function uvlitem.title(self)
783         return self:scheme() and self:scheme('title') or
784                 self.cref[3] or self.cref[2] or self.cref[1]
785 end
786
787 function uvlitem.type(self)
788         if self.t == luci.uvl.TYPE_CONFIG then
789                 return 'config'
790         elseif self.t == luci.uvl.TYPE_SECTION then
791                 return 'section'
792         elseif self.t == luci.uvl.TYPE_OPTION then
793                 return 'option'
794         elseif self.t == luci.uvl.TYPE_ENUM then
795                 return 'enum'
796         end
797 end
798
799 function uvlitem.error(self, ...)
800         if not self.e then
801                 local errconst = { ERR.CONFIG, ERR.SECTION, ERR.OPTION, ERR.OPTION }
802                 self.e = errconst[#self.cref]( self )
803         end
804
805         return self.e:child( ... )
806 end
807
808 function uvlitem.errors(self)
809         return self.e
810 end
811
812 function uvlitem.ok(self)
813         return not self:errors()
814 end
815
816 function uvlitem.parent(self)
817         if self.p then
818                 return self.p
819         elseif #self.cref == 3 or #self.cref == 4 then
820                 return luci.uvl.section( self.s, self.c, self.cref[1], self.cref[2] )
821         elseif #self.cref == 2 then
822                 return luci.uvl.config( self.s, self.c, self.cref[1] )
823         else
824                 return nil
825         end
826 end
827
828 function uvlitem._loadconf(self, co, c)
829         if not co then
830                 local uci, err = luci.model.uci.cursor(), nil
831                 co, err = uci:get_all(c)
832
833                 if err then
834                         self:error(ERR.UCILOAD(self, err))
835                 end
836         end
837         return co
838 end
839
840
841 --- Object representation of a scheme.
842 -- @class       scheme
843 -- @cstyle      instance
844 -- @name        luci.uvl.scheme
845
846 --- Scheme instance constructor.
847 -- @class                       function
848 -- @name                        scheme
849 -- @param scheme        Scheme instance
850 -- @param co            Configuration data
851 -- @param c                     Configuration name
852 -- @return                      Config instance
853 scheme = luci.util.class(uvlitem)
854
855 function scheme.__init__(self, scheme, co, c)
856         if not c then
857                 c, co = co, nil
858         end
859
860         self.cref = { c }
861         self.sref = { c }
862         self.c    = self:_loadconf(co, c)
863         self.s    = scheme
864         self.t    = luci.uvl.TYPE_SCHEME
865 end
866
867 --- Add an error to scheme.
868 -- @return      Scheme error context
869 function scheme.error(self, ...)
870         if not self.e then self.e = ERR.SCHEME( self ) end
871         return self.e:child( ... )
872 end
873
874 --- Get an associated config object.
875 -- @return      Config instance
876 function scheme.config(self)
877         local co = luci.uvl.config( self.s, self.cref[1] )
878               co.p = self
879
880         return co
881 end
882
883 --- Get all section objects associated with this scheme.
884 -- @return      Table containing all associated luci.uvl.section instances
885 function scheme.sections(self)
886         local v = { }
887         if self.s.packages[self.sref[1]].sections then
888                 for o, _ in pairs( self.s.packages[self.sref[1]].sections ) do
889                         table.insert( v, luci.uvl.option(
890                                 self.s, self.c, self.cref[1], self.cref[2], o
891                         ) )
892                 end
893         end
894         return v
895 end
896
897 --- Get an associated section object.
898 -- @param s     Section to select
899 -- @return      Section instance
900 function scheme.section(self, s)
901         local so = luci.uvl.section( self.s, self.c, self.cref[1], s )
902               so.p = self
903
904         return so
905 end
906
907
908 --- Object representation of a config.
909 -- @class       config
910 -- @cstyle      instance
911 -- @name        luci.uvl.config
912
913 --- Config instance constructor.
914 -- @class                       function
915 -- @name                        config
916 -- @param scheme        Scheme instance
917 -- @param co            Configuration data
918 -- @param c                     Configuration name
919 -- @return                      Config instance
920 config = luci.util.class(uvlitem)
921
922 function config.__init__(self, scheme, co, c)
923         if not c then
924                 c, co = co, nil
925         end
926
927         self.cref = { c }
928         self.sref = { c }
929         self.c    = self:_loadconf(co, c)
930         self.s    = scheme
931         self.t    = luci.uvl.TYPE_CONFIG
932 end
933
934 --- Get all section objects associated with this config.
935 -- @return      Table containing all associated luci.uvl.section instances
936 function config.sections(self)
937         local v = { }
938         if self.s.packages[self.sref[1]].sections then
939                 for o, _ in pairs( self.s.packages[self.sref[1]].sections ) do
940                         table.insert( v, luci.uvl.option(
941                                 self.s, self.c, self.cref[1], self.cref[2], o
942                         ) )
943                 end
944         end
945         return v
946 end
947
948 --- Get an associated section object.
949 -- @param s     Section to select
950 -- @return      Section instance
951 function config.section(self, s)
952         local so = luci.uvl.section( self.s, self.c, self.cref[1], s )
953               so.p = self
954
955         return so
956 end
957
958
959 --- Object representation of a scheme/config section.
960 -- @class       module
961 -- @cstyle      instance
962 -- @name        luci.uvl.section
963
964 --- Section instance constructor.
965 -- @class                       function
966 -- @name                        section
967 -- @param scheme        Scheme instance
968 -- @param co            Configuration data
969 -- @param c                     Configuration name
970 -- @param s                     Section name
971 -- @return                      Section instance
972 section = luci.util.class(uvlitem)
973
974 function section.__init__(self, scheme, co, c, s)
975         self.cref = { c, s }
976         self.sref = { c, co and co[s] and co[s]['.type'] or s }
977         self.c    = self:_loadconf(co, c)
978         self.s    = scheme
979         self.t    = luci.uvl.TYPE_SECTION
980 end
981
982 --- Get all option objects associated with this section.
983 -- @return      Table containing all associated luci.uvl.option instances
984 function section.variables(self)
985         local v = { }
986         if self.s.packages[self.sref[1]].variables[self.sref[2]] then
987                 for o, _ in pairs(
988                         self.s.packages[self.sref[1]].variables[self.sref[2]]
989                 ) do
990                         table.insert( v, luci.uvl.option(
991                                 self.s, self.c, self.cref[1], self.cref[2], o
992                         ) )
993                 end
994         end
995         return v
996 end
997
998 --- Get an associated option object.
999 -- @param o     Option to select
1000 -- @return      Option instance
1001 function section.option(self, o)
1002         local oo = luci.uvl.option( self.s, self.c, self.cref[1], self.cref[2], o )
1003               oo.p = self
1004
1005         return oo
1006 end
1007
1008
1009 --- Object representation of a scheme/config option.
1010 -- @class       module
1011 -- @cstyle      instance
1012 -- @name        luci.uvl.option
1013
1014 --- Section instance constructor.
1015 -- @class                       function
1016 -- @name                        option
1017 -- @param scheme        Scheme instance
1018 -- @param co            Configuration data
1019 -- @param c                     Configuration name
1020 -- @param s                     Section name
1021 -- @param o                     Option name
1022 -- @return                      Option instance
1023 option = luci.util.class(uvlitem)
1024
1025 function option.__init__(self, scheme, co, c, s, o)
1026         self.cref = { c, s, o }
1027         self.sref = { c, co and co[s] and co[s]['.type'] or s, o }
1028         self.c    = self:_loadconf(co, c)
1029         self.s    = scheme
1030         self.t    = luci.uvl.TYPE_OPTION
1031 end
1032
1033 --- Get the value of this option.
1034 -- @return      The associated configuration value
1035 function option.value(self)
1036         return self:config()
1037 end
1038
1039 --- Get the associated section information in scheme.
1040 -- @return      Table containing the scheme properties
1041 function option.section(self)
1042         return self.s.packages[self.sref[1]].sections[self.sref[2]]
1043 end
1044
1045 --- Construct an enum object instance from given or default value.
1046 -- @param v     Value to select
1047 -- @return      Enum instance for selected value
1048 function option.enum(self, val)
1049         return enum(
1050                 self.s, self.c,
1051                 self.cref[1], self.cref[2], self.cref[3],
1052                 val or self:value()
1053         )
1054 end
1055
1056
1057 --- Object representation of a enum value.
1058 -- @class       module
1059 -- @cstyle      instance
1060 -- @name        luci.uvl.enum
1061
1062 --- Section instance constructor.
1063 -- @class                       function
1064 -- @name                        enum
1065 -- @param scheme        Scheme instance
1066 -- @param co            Configuration data
1067 -- @param c                     Configuration name
1068 -- @param s                     Section name
1069 -- @param o                     Enum name
1070 -- @param v                     Enum value
1071 -- @return                      Enum value instance
1072 enum = luci.util.class(option)
1073
1074 function enum.__init__(self, scheme, co, c, s, o, v)
1075         self.cref = { c, s, o, v }
1076         self.sref = { c, co and co[s] and co[s]['.type'] or s, o, v }
1077         self.c    = self:_loadconf(co, c)
1078         self.s    = scheme
1079         self.t    = luci.uvl.TYPE_ENUM
1080 end