libs/core/luasrc/util.lua

   1 --[[
   2 LuCI - Utility library
   3
   4 Description:
   5 Several common useful Lua functions
   6
   7 FileId:
   8 $Id$
   9
  10 License:
  11 Copyright 2008 Steven Barth <steven@midlink.org>
  12
  13 Licensed under the Apache License, Version 2.0 (the "License");
  14 you may not use this file except in compliance with the License.
  15 You may obtain a copy of the License at
  16
  17         http://www.apache.org/licenses/LICENSE-2.0
  18
  19 Unless required by applicable law or agreed to in writing, software
  20 distributed under the License is distributed on an "AS IS" BASIS,
  21 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  22 See the License for the specific language governing permissions and
  23 limitations under the License.
  24
  25 ]]--
  26
  27 --- LuCI utility functions.
  28 module("luci.util", package.seeall)
  29
  30 --
  31 -- Class helper routines
  32 --
  33
  34 --- Create a Class object (Python-style object model).
  35 -- The class object can be instantiated by calling itself.
  36 -- Any class functions or shared parameters can be attached to this object.
  37 -- Attaching a table to the class object makes this table shared between
  38 -- all instances of this class. For object parameters use the __init__ function.
  39 -- Classes can inherit member functions and values from a base class.
  40 -- Class can be instantiated by calling them. All parameters will be passed
  41 -- to the __init__ function of this class - if such a function exists.
  42 -- The __init__ function must be used to set any object parameters that are not shared
  43 -- with other objects of this class. Any return values will be ignored.
  44 -- @param base  The base class to inherit from (optional)
  45 -- @return              A class object
  46 -- @see                 instanceof
  47 -- @see                 clone
  48 function class(base)
  49         local class = {}
  50
  51         local create = function(class, ...)
  52                 local inst = {}
  53                 setmetatable(inst, {__index = class})
  54
  55                 if inst.__init__ then
  56                         local stat, err = copcall(inst.__init__, inst, ...)
  57                         if not stat then
  58                                 error(err)
  59                         end
  60                 end
  61
  62                 return inst
  63         end
  64
  65         local classmeta = {__call = create}
  66
  67         if base then
  68                 classmeta.__index = base
  69         end
  70
  71         setmetatable(class, classmeta)
  72         return class
  73 end
  74
  75 --- Test whether the given object is an instance of the given class.
  76 -- @param object        Object instance
  77 -- @param class         Class object to test against
  78 -- @return                      Boolean indicating whether the object is an instance
  79 -- @see                         class
  80 -- @see                         clone
  81 function instanceof(object, class)
  82         local meta = getmetatable(object)
  83         while meta and meta.__index do
  84                 if meta.__index == class then
  85                         return true
  86                 end
  87                 meta = getmetatable(meta.__index)
  88         end
  89         return false
  90 end
  91
  92
  93 --
  94 -- Scope manipulation routines
  95 --
  96
  97 --- Replace a function scope with a shallow copy of itself.
  98 -- This is useful if you want to get rid of several unwanted side effects
  99 -- while changing the scope of a certain Lua function.
 100 -- @param f             Lua function
 101 function resfenv(f)
 102         setfenv(f, clone(getfenv(f)))
 103 end
 104
 105 --- Store given object associated with given key in the scope of a function.
 106 -- @param f             Lua function
 107 -- @param key   String value containg the key of the object to store
 108 -- @param obj   Object to store in the scope
 109 -- @return              Always nil
 110 -- @see updfenv
 111 -- @see resfenv
 112 function extfenv(f, key, obj)
 113         local scope = getfenv(f)
 114         scope[key] = obj
 115 end
 116
 117 --- Extend the scope of a function with the contents of a table
 118 -- @param f             Lua function
 119 -- @param key   String value containg the key of the object to store
 120 -- @param obj   Object to store in the scope
 121 -- @return              Always nil
 122 -- @see extfenv
 123 -- @see resfenv
 124 function updfenv(f, extscope)
 125         update(getfenv(f), extscope)
 126 end
 127
 128 --- Create a new or get an already existing thread local store associated with
 129 -- the current active coroutine. A thread local store is private a table object
 130 -- whose values can't be accessed from outside of the running coroutine.
 131 -- @return      Table value representing the corresponding thread local store
 132 function threadlocal()
 133         local tbl = {}
 134
 135         local function get(self, key)
 136                 local c = coroutine.running()
 137                 local thread = coxpt[c] or c or 0
 138                 if not rawget(self, thread) then
 139                         return nil
 140                 end
 141                 return rawget(self, thread)[key]
 142         end
 143
 144         local function set(self, key, value)
 145                 local c = coroutine.running()
 146                 local thread = coxpt[c] or c or 0
 147                 if not rawget(self, thread) then
 148                         rawset(self, thread, {})
 149                 end
 150                 rawget(self, thread)[key] = value
 151         end
 152
 153         setmetatable(tbl, {__index = get, __newindex = set, __mode = "k"})
 154
 155         return tbl
 156 end
 157
 158
 159 --
 160 -- Debugging routines
 161 --
 162
 163 --- Write given object to stderr.
 164 -- @param obj   Value to write to stderr
 165 -- @return              Boolean indicating whether the write operation was successful
 166 function perror(obj)
 167         return io.stderr:write(tostring(obj) .. "\n")
 168 end
 169
 170 --- Recursively dumps a table to stdout, useful for testing and debugging.
 171 -- @param t     Table value to dump
 172 -- @param i     Number of tabs to prepend to each line
 173 -- @return      Always nil
 174 function dumptable(t, i)
 175         i = i or 0
 176         for k,v in pairs(t) do
 177                 print(string.rep("\t", i) .. tostring(k), tostring(v))
 178                 if type(v) == "table" then
 179                         dumptable(v, i+1)
 180                 end
 181         end
 182 end
 183
 184
 185 --
 186 -- String and data manipulation routines
 187 --
 188
 189 --- Escapes all occurrences of the given character in given string.
 190 -- @param s     String value containing unescaped characters
 191 -- @param c     String value with character to escape (optional, defaults to "\")
 192 -- @return      String value with each occurrence of character escaped with "\"
 193 function escape(s, c)
 194         c = c or "\\"
 195         return s:gsub(c, "\\" .. c)
 196 end
 197
 198 --- Create valid XML PCDATA from given string.
 199 -- @param value String value containing the data to escape
 200 -- @return              String value containing the escaped data
 201 function pcdata(value)
 202         if not value then return end
 203         value = tostring(value)
 204         value = value:gsub("&", "&amp;")
 205         value = value:gsub('"', "&quot;")
 206         value = value:gsub("'", "&apos;")
 207         value = value:gsub("<", "&lt;")
 208         return value:gsub(">", "&gt;")
 209 end
 210
 211 --- Splits given string on a defined separator sequence and return a table
 212 -- containing the resulting substrings. The optional max parameter specifies
 213 -- the number of bytes to process, regardless of the actual length of the given
 214 -- string. The optional last parameter, regex, specifies whether the separator
 215 -- sequence is interpreted as regular expression.
 216 -- @param str           String value containing the data to split up
 217 -- @param pat           String with separator pattern (optional, defaults to "\n")
 218 -- @param max           Maximum times to split (optional)
 219 -- @param regex         Boolean indicating whether to interpret the separator
 220 --                                      pattern as regular expression (optional, default is false)
 221 -- @return                      Table containing the resulting substrings
 222 function split(str, pat, max, regex)
 223         pat = pat or "\n"
 224         max = max or #str
 225
 226         local t = {}
 227         local c = 1
 228
 229         if #str == 0 then
 230                 return {""}
 231         end
 232
 233         if #pat == 0 then
 234                 return nil
 235         end
 236
 237         if max == 0 then
 238                 return str
 239         end
 240
 241         repeat
 242                 local s, e = str:find(pat, c, not regex)
 243                 max = max - 1
 244                 if s and max < 0 then
 245                         table.insert(t, str:sub(c))
 246                 else
 247                         table.insert(t, str:sub(c, s and s - 1))
 248                 end
 249                 c = e and e + 1 or #str + 1
 250         until not s or max < 0
 251
 252         return t
 253 end
 254
 255 --- Remove leading and trailing whitespace from given string value.
 256 -- @param str   String value containing whitespace padded data
 257 -- @return              String value with leading and trailing space removed
 258 function trim(str)
 259         local s = str:gsub("^%s*(.-)%s*$", "%1")
 260         return s
 261 end
 262
 263 --- Parse certain units from the given string and return the canonical integer
 264 -- value or 0 if the unit is unknown. Upper- or lower case is irrelevant.
 265 -- Recognized units are:
 266 --      o "y"   - one year   (60*60*24*366)
 267 --  o "m"       - one month  (60*60*24*31)
 268 --  o "w"       - one week   (60*60*24*7)
 269 --  o "d"       - one day    (60*60*24)
 270 --  o "h"       - one hour       (60*60)
 271 --  o "min"     - one minute (60)
 272 --  o "kb"  - one kilobyte (1024)
 273 --  o "mb"      - one megabyte (1024*1024)
 274 --  o "gb"      - one gigabyte (1024*1024*1024)
 275 --  o "kib" - one si kilobyte (1000)
 276 --  o "mib"     - one si megabyte (1000*1000)
 277 --  o "gib"     - one si gigabyte (1000*1000*1000)
 278 -- @param ustr  String containing a numerical value with trailing unit
 279 -- @return              Number containing the canonical value
 280 function parse_units(ustr)
 281
 282         local val = 0
 283
 284         -- unit map
 285         local map = {
 286                 -- date stuff
 287                 y   = 60 * 60 * 24 * 366,
 288                 m   = 60 * 60 * 24 * 31,
 289                 w   = 60 * 60 * 24 * 7,
 290                 d   = 60 * 60 * 24,
 291                 h   = 60 * 60,
 292                 min = 60,
 293
 294                 -- storage sizes
 295                 kb  = 1024,
 296                 mb  = 1024 * 1024,
 297                 gb  = 1024 * 1024 * 1024,
 298
 299                 -- storage sizes (si)
 300                 kib = 1000,
 301                 mib = 1000 * 1000,
 302                 gib = 1000 * 1000 * 1000
 303         }
 304
 305         -- parse input string
 306         for spec in ustr:lower():gmatch("[0-9%.]+[a-zA-Z]*") do
 307
 308                 local num = spec:gsub("[^0-9%.]+$","")
 309                 local spn = spec:gsub("^[0-9%.]+", "")
 310
 311                 if map[spn] or map[spn:sub(1,1)] then
 312                         val = val + num * ( map[spn] or map[spn:sub(1,1)] )
 313                 else
 314                         val = val + num
 315                 end
 316         end
 317
 318
 319         return val
 320 end
 321
 322 --- Combines two or more numerically indexed tables into one.
 323 -- @param tbl1  Table value to combine
 324 -- @param tbl2  Table value to combine
 325 -- @param ...   More tables to combine
 326 -- @return              Table value containing all values of given tables
 327 function combine(...)
 328         local result = {}
 329         for i, a in ipairs(arg) do
 330                 for j, v in ipairs(a) do
 331                         table.insert(result, v)
 332                 end
 333         end
 334         return result
 335 end
 336
 337 --- Checks whether the given table contains the given value.
 338 -- @param table Table value
 339 -- @param value Value to search within the given table
 340 -- @return              Boolean indicating whether the given value occurs within table
 341 function contains(table, value)
 342         for k, v in pairs(table) do
 343                 if value == v then
 344                         return k
 345                 end
 346         end
 347         return false
 348 end
 349
 350 --- Update values in given table with the values from the second given table.
 351 -- Both table are - in fact - merged together.
 352 -- @param t                     Table which should be updated
 353 -- @param updates       Table containing the values to update
 354 -- @return                      Always nil
 355 function update(t, updates)
 356         for k, v in pairs(updates) do
 357                 t[k] = v
 358         end
 359 end
 360
 361 --- Clones the given object and return it's copy.
 362 -- @param object        Table value to clone
 363 -- @param deep          Boolean indicating whether to do recursive cloning
 364 -- @return                      Cloned table value
 365 function clone(object, deep)
 366         local copy = {}
 367
 368         for k, v in pairs(object) do
 369                 if deep and type(v) == "table" then
 370                         v = clone(v, deep)
 371                 end
 372                 copy[k] = v
 373         end
 374
 375         setmetatable(copy, getmetatable(object))
 376
 377         return copy
 378 end
 379
 380
 381 --- Create a dynamic table which automatically creates subtables.
 382 -- @return      Dynamic Table
 383 function dtable()
 384         return setmetatable({}, { __index =
 385                 function(tbl, key)
 386                         return rawget(tbl, key)
 387                          or rawget(rawset(tbl, key, dtable()), key)
 388                 end
 389         })
 390 end
 391
 392
 393 -- Serialize the contents of a table value.
 394 function _serialize_table(t)
 395         local data = ""
 396         for k, v in pairs(t) do
 397                 k = serialize_data(k)
 398                 v = serialize_data(v)
 399                 data = data .. ( #data > 0 and ", " or "" ) ..
 400                         '[' .. k .. '] = ' .. v
 401         end
 402         return data
 403 end
 404
 405 --- Recursively serialize given data to lua code, suitable for restoring
 406 -- with loadstring().
 407 -- @param val   Value containing the data to serialize
 408 -- @return              String value containing the serialized code
 409 -- @see                 restore_data
 410 -- @see                 get_bytecode
 411 function serialize_data(val)
 412         if val == nil then
 413                 return "nil"
 414         elseif type(val) == "number" then
 415                 return val
 416         elseif type(val) == "string" then
 417                 return string.format("%q", val)
 418         elseif type(val) == "boolean" then
 419                 return val and "true" or "false"
 420         elseif type(val) == "function" then
 421                 return string.format("loadstring(%q)", get_bytecode(val))
 422         elseif type(val) == "table" then
 423                 return "{ " .. _serialize_table(val) .. " }"
 424         else
 425                 return '"[unhandled data type:' .. type(val) .. ']"'
 426         end
 427 end
 428
 429 --- Restore data previously serialized with serialize_data().
 430 -- @param str   String containing the data to restore
 431 -- @return              Value containing the restored data structure
 432 -- @see                 serialize_data
 433 -- @see                 get_bytecode
 434 function restore_data(str)
 435         return loadstring("return " .. str)()
 436 end
 437
 438
 439 --
 440 -- Byte code manipulation routines
 441 --
 442
 443 --- Return the current runtime bytecode of the given data. The byte code
 444 -- will be stripped before it is returned.
 445 -- @param val   Value to return as bytecode
 446 -- @return              String value containing the bytecode of the given data
 447 function get_bytecode(val)
 448         local code
 449
 450         if type(val) == "function" then
 451                 code = string.dump(val)
 452         else
 453                 code = string.dump( loadstring( "return " .. serialize_data(val) ) )
 454         end
 455
 456         return code and strip_bytecode(code)
 457 end
 458
 459 --- Strips unnescessary lua bytecode from given string. Information like line
 460 -- numbers and debugging numbers will be discarded. Original version by
 461 -- Peter Cawley (http://lua-users.org/lists/lua-l/2008-02/msg01158.html)
 462 -- @param code  String value containing the original lua byte code
 463 -- @return              String value containing the stripped lua byte code
 464 function strip_bytecode(code)
 465         local version, format, endian, int, size, ins, num, lnum = code:byte(5, 12)
 466         local subint
 467         if endian == 1 then
 468                 subint = function(code, i, l)
 469                         local val = 0
 470                         for n = l, 1, -1 do
 471                                 val = val * 256 + code:byte(i + n - 1)
 472                         end
 473                         return val, i + l
 474                 end
 475         else
 476                 subint = function(code, i, l)
 477                         local val = 0
 478                         for n = 1, l, 1 do
 479                                 val = val * 256 + code:byte(i + n - 1)
 480                         end
 481                         return val, i + l
 482                 end
 483         end
 484
 485         local strip_function
 486         strip_function = function(code)
 487                 local count, offset = subint(code, 1, size)
 488                 local stripped, dirty = string.rep("\0", size), offset + count
 489                 offset = offset + count + int * 2 + 4
 490                 offset = offset + int + subint(code, offset, int) * ins
 491                 count, offset = subint(code, offset, int)
 492                 for n = 1, count do
 493                         local t
 494                         t, offset = subint(code, offset, 1)
 495                         if t == 1 then
 496                                 offset = offset + 1
 497                         elseif t == 4 then
 498                                 offset = offset + size + subint(code, offset, size)
 499                         elseif t == 3 then
 500                                 offset = offset + num
 501                         elseif t == 254 or t == 9 then
 502                                 offset = offset + lnum
 503                         end
 504                 end
 505                 count, offset = subint(code, offset, int)
 506                 stripped = stripped .. code:sub(dirty, offset - 1)
 507                 for n = 1, count do
 508                         local proto, off = strip_function(code:sub(offset, -1))
 509                         stripped, offset = stripped .. proto, offset + off - 1
 510                 end
 511                 offset = offset + subint(code, offset, int) * int + int
 512                 count, offset = subint(code, offset, int)
 513                 for n = 1, count do
 514                         offset = offset + subint(code, offset, size) + size + int * 2
 515                 end
 516                 count, offset = subint(code, offset, int)
 517                 for n = 1, count do
 518                         offset = offset + subint(code, offset, size) + size
 519                 end
 520                 stripped = stripped .. string.rep("\0", int * 3)
 521                 return stripped, offset
 522         end
 523
 524         return code:sub(1,12) .. strip_function(code:sub(13,-1))
 525 end
 526
 527
 528 --
 529 -- Sorting iterator functions
 530 --
 531
 532 function _sortiter( t, f )
 533         local keys = { }
 534
 535         for k, v in pairs(t) do
 536                 table.insert( keys, k )
 537         end
 538
 539         local _pos = 0
 540         local _len = table.getn( keys )
 541
 542         table.sort( keys, f )
 543
 544         return function()
 545                 _pos = _pos + 1
 546                 if _pos <= _len then
 547                         return keys[_pos], t[keys[_pos]]
 548                 end
 549         end
 550 end
 551
 552 --- Return a key, value iterator which returns the values sorted according to
 553 -- the provided callback function.
 554 -- @param t     The table to iterate
 555 -- @param f A callback function to decide the order of elements
 556 -- @return      Function value containing the corresponding iterator
 557 function spairs(t,f)
 558         return _sortiter( t, f )
 559 end
 560
 561 --- Return a key, value iterator for the given table.
 562 -- The table pairs are sorted by key.
 563 -- @param t     The table to iterate
 564 -- @return      Function value containing the corresponding iterator
 565 function kspairs(t)
 566         return _sortiter( t )
 567 end
 568
 569 --- Return a key, value iterator for the given table.
 570 -- The table pairs are sorted by value.
 571 -- @param t     The table to iterate
 572 -- @return      Function value containing the corresponding iterator
 573 function vspairs(t)
 574         return _sortiter( t, function (a,b) return t[a] < t[b] end )
 575 end
 576
 577
 578 --
 579 -- System utility functions
 580 --
 581
 582 --- Test whether the current system is operating in big endian mode.
 583 -- @return      Boolean value indicating whether system is big endian
 584 function bigendian()
 585         return string.byte(string.dump(function() end), 7) == 0
 586 end
 587
 588 --- Execute given commandline and gather stdout.
 589 -- @param command       String containing command to execute
 590 -- @return                      String containing the command's stdout
 591 function exec(command)
 592         local pp   = io.popen(command)
 593         local data = pp:read("*a")
 594         pp:close()
 595
 596         return data
 597 end
 598
 599 --- Return a line-buffered iterator over the output of given command.
 600 -- @param command       String containing the command to execute
 601 -- @return                      Iterator
 602 function execi(command)
 603         local pp = io.popen(command)
 604
 605         return pp and function()
 606                 local line = pp:read()
 607
 608                 if not line then
 609                         pp:close()
 610                 end
 611
 612                 return line
 613         end
 614 end
 615
 616 -- Deprecated
 617 function execl(command)
 618         local pp   = io.popen(command)
 619         local line = ""
 620         local data = {}
 621
 622         while true do
 623                 line = pp:read()
 624                 if (line == nil) then break end
 625                 table.insert(data, line)
 626         end
 627         pp:close()
 628
 629         return data
 630 end
 631
 632 --- Returns the absolute path to LuCI base directory.
 633 -- @return              String containing the directory path
 634 function libpath()
 635         return luci.fs.dirname(require("luci.debug").__file__)
 636 end
 637
 638
 639 --
 640 -- Coroutine safe xpcall and pcall versions modified for Luci
 641 -- original version:
 642 -- coxpcall 1.13 - Copyright 2005 - Kepler Project (www.keplerproject.org)
 643 --
 644 -- Copyright © 2005 Kepler Project.
 645 -- Permission is hereby granted, free of charge, to any person obtaining a
 646 -- copy of this software and associated documentation files (the "Software"),
 647 -- to deal in the Software without restriction, including without limitation
 648 -- the rights to use, copy, modify, merge, publish, distribute, sublicense,
 649 -- and/or sell copies of the Software, and to permit persons to whom the
 650 -- Software is furnished to do so, subject to the following conditions:
 651 --
 652 -- The above copyright notice and this permission notice shall be
 653 -- included in all copies or substantial portions of the Software.
 654 --
 655 -- THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 656 -- EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
 657 -- OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
 658 -- IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
 659 -- DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
 660 -- TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE
 661 -- OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 662
 663 local performResume, handleReturnValue
 664 local oldpcall, oldxpcall = pcall, xpcall
 665 coxpt = {}
 666 setmetatable(coxpt, {__mode = "kv"})
 667
 668 -- Identity function for copcall
 669 local function copcall_id(trace, ...)
 670   return ...
 671 end
 672
 673 --- This is a coroutine-safe drop-in replacement for Lua's "xpcall"-function
 674 -- @param f             Lua function to be called protected
 675 -- @param err   Custom error handler
 676 -- @param ...   Parameters passed to the function
 677 -- @return              A boolean whether the function call succeeded and the return
 678 --                              values of either the function or the error handler
 679 function coxpcall(f, err, ...)
 680         local res, co = oldpcall(coroutine.create, f)
 681         if not res then
 682                 local params = {...}
 683                 local newf = function() return f(unpack(params)) end
 684                 co = coroutine.create(newf)
 685         end
 686         local c = coroutine.running()
 687         coxpt[co] = coxpt[c] or c or 0
 688
 689         return performResume(err, co, ...)
 690 end
 691
 692 --- This is a coroutine-safe drop-in replacement for Lua's "pcall"-function
 693 -- @param f             Lua function to be called protected
 694 -- @param ...   Parameters passed to the function
 695 -- @return              A boolean whether the function call succeeded and the returns
 696 --                              values of the function or the error object
 697 function copcall(f, ...)
 698         return coxpcall(f, copcall_id, ...)
 699 end
 700
 701 -- Handle return value of protected call
 702 function handleReturnValue(err, co, status, ...)
 703         if not status then
 704                 return false, err(debug.traceback(co, (...)), ...)
 705         end
 706         if coroutine.status(co) == 'suspended' then
 707                 return performResume(err, co, coroutine.yield(...))
 708         else
 709                 return true, ...
 710         end
 711 end
 712
 713 -- Resume execution of protected function call
 714 function performResume(err, co, ...)
 715         return handleReturnValue(err, co, coroutine.resume(co, ...))
 716 end