5 Several common useful Lua functions
11 Copyright 2008 Steven Barth <steven@midlink.org>
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
17 http://www.apache.org/licenses/LICENSE-2.0
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.
27 local io = require "io"
28 local math = require "math"
29 local table = require "table"
30 local debug = require "debug"
31 local ldebug = require "luci.debug"
32 local string = require "string"
33 local coroutine = require "coroutine"
34 local cutil = require "luci.cutil"
36 local getmetatable, setmetatable = getmetatable, setmetatable
37 local rawget, rawset, unpack = rawget, rawset, unpack
38 local tostring, type, assert = tostring, type, assert
39 local ipairs, pairs, loadstring = ipairs, pairs, loadstring
40 local require, pcall, xpcall = require, pcall, xpcall
42 --- LuCI utility functions.
46 -- Pythonic string formatting extension
49 getmetatable("").__mod = function(a, b)
52 elseif type(b) == "table" then
53 return a:format(unpack(b))
62 -- Class helper routines
65 -- Instantiates a class
67 local function _instantiate(class, ...)
68 local inst = setmetatable({}, {__index = class})
78 --- Create a Class object (Python-style object model).
79 -- The class object can be instantiated by calling itself.
80 -- Any class functions or shared parameters can be attached to this object.
81 -- Attaching a table to the class object makes this table shared between
82 -- all instances of this class. For object parameters use the __init__ function.
83 -- Classes can inherit member functions and values from a base class.
84 -- Class can be instantiated by calling them. All parameters will be passed
85 -- to the __init__ function of this class - if such a function exists.
86 -- The __init__ function must be used to set any object parameters that are not shared
87 -- with other objects of this class. Any return values will be ignored.
88 -- @param base The base class to inherit from (optional)
89 -- @return A class object
94 return setmetatable({}, {
95 __call = _instantiate,
102 --- Test whether the given object is an instance of the given class.
103 -- @param object Object instance
104 -- @param class Class object to test against
105 -- @return Boolean indicating whether the object is an instance
109 function instanceof(object, class)
110 local meta = getmetatable(object)
111 while meta and meta.__index do
112 if meta.__index == class then
115 meta = getmetatable(meta.__index)
120 instanceof = cutil.instanceof
124 -- Scope manipulation routines
127 --- Create a new or get an already existing thread local store associated with
128 -- the current active coroutine. A thread local store is private a table object
129 -- whose values can't be accessed from outside of the running coroutine.
130 -- @return Table value representing the corresponding thread local store
131 function threadlocal()
134 local function get(self, key)
135 local c = coroutine.running()
136 local thread = coxpt[c] or c or 0
137 if not rawget(self, thread) then
140 return rawget(self, thread)[key]
143 local function set(self, key, value)
144 local c = coroutine.running()
145 local thread = coxpt[c] or c or 0
146 if not rawget(self, thread) then
147 rawset(self, thread, {})
149 rawget(self, thread)[key] = value
152 setmetatable(tbl, {__index = get, __newindex = set, __mode = "k"})
159 -- Debugging routines
162 --- Write given object to stderr.
163 -- @param obj Value to write to stderr
164 -- @return Boolean indicating whether the write operation was successful
166 return io.stderr:write(tostring(obj) .. "\n")
169 --- Recursively dumps a table to stdout, useful for testing and debugging.
170 -- @param t Table value to dump
171 -- @param maxdepth Maximum depth
172 -- @return Always nil
173 function dumptable(t, maxdepth, i, seen)
175 seen = seen or setmetatable({}, {__mode="k"})
177 for k,v in pairs(t) do
178 perror(string.rep("\t", i) .. tostring(k) .. "\t" .. tostring(v))
179 if type(v) == "table" and (not maxdepth or i < maxdepth) then
182 dumptable(v, maxdepth, i+1, seen)
184 perror(string.rep("\t", i) .. "*** RECURSION ***")
192 -- String and data manipulation routines
195 --- Escapes all occurrences of the given character in given string.
196 -- @param s String value containing unescaped characters
197 -- @param c String value with character to escape (optional, defaults to "\")
198 -- @return String value with each occurrence of character escaped with "\"
199 function escape(s, c)
201 return s:gsub(c, "\\" .. c)
204 --- Create valid XML PCDATA from given string.
205 -- @param value String value containing the data to escape
206 -- @return String value containing the escaped data
208 function pcdata(value)
209 return value and tostring(value):gsub("[&\"'<>]", {
218 pcdata = cutil.pcdata
220 --- Strip HTML tags from given string.
221 -- @param value String containing the HTML text
222 -- @return String with HTML tags stripped of
223 function striptags(s)
224 return pcdata(s:gsub("</?[A-Za-z][A-Za-z0-9:_%-]*[^>]*>", " "):gsub("%s+", " "))
227 --- Splits given string on a defined separator sequence and return a table
228 -- containing the resulting substrings. The optional max parameter specifies
229 -- the number of bytes to process, regardless of the actual length of the given
230 -- string. The optional last parameter, regex, specifies whether the separator
231 -- sequence is interpreted as regular expression.
232 -- @param str String value containing the data to split up
233 -- @param pat String with separator pattern (optional, defaults to "\n")
234 -- @param max Maximum times to split (optional)
235 -- @param regex Boolean indicating whether to interpret the separator
236 -- pattern as regular expression (optional, default is false)
237 -- @return Table containing the resulting substrings
238 function split(str, pat, max, regex)
258 local s, e = str:find(pat, c, not regex)
260 if s and max < 0 then
263 t[#t+1] = str:sub(c, s and s - 1)
265 c = e and e + 1 or #str + 1
266 until not s or max < 0
271 --- Remove leading and trailing whitespace from given string value.
272 -- @param str String value containing whitespace padded data
273 -- @return String value with leading and trailing space removed
275 return (str:gsub("^%s*(.-)%s*$", "%1"))
278 --- Count the occurences of given substring in given string.
279 -- @param str String to search in
280 -- @param pattern String containing pattern to find
281 -- @return Number of found occurences
282 function cmatch(str, pat)
284 for _ in str:gmatch(pat) do count = count + 1 end
288 --- Parse certain units from the given string and return the canonical integer
289 -- value or 0 if the unit is unknown. Upper- or lower case is irrelevant.
290 -- Recognized units are:
291 -- o "y" - one year (60*60*24*366)
292 -- o "m" - one month (60*60*24*31)
293 -- o "w" - one week (60*60*24*7)
294 -- o "d" - one day (60*60*24)
295 -- o "h" - one hour (60*60)
296 -- o "min" - one minute (60)
297 -- o "kb" - one kilobyte (1024)
298 -- o "mb" - one megabyte (1024*1024)
299 -- o "gb" - one gigabyte (1024*1024*1024)
300 -- o "kib" - one si kilobyte (1000)
301 -- o "mib" - one si megabyte (1000*1000)
302 -- o "gib" - one si gigabyte (1000*1000*1000)
303 -- @param ustr String containing a numerical value with trailing unit
304 -- @return Number containing the canonical value
305 function parse_units(ustr)
312 y = 60 * 60 * 24 * 366,
313 m = 60 * 60 * 24 * 31,
314 w = 60 * 60 * 24 * 7,
322 gb = 1024 * 1024 * 1024,
324 -- storage sizes (si)
327 gib = 1000 * 1000 * 1000
330 -- parse input string
331 for spec in ustr:lower():gmatch("[0-9%.]+[a-zA-Z]*") do
333 local num = spec:gsub("[^0-9%.]+$","")
334 local spn = spec:gsub("^[0-9%.]+", "")
336 if map[spn] or map[spn:sub(1,1)] then
337 val = val + num * ( map[spn] or map[spn:sub(1,1)] )
347 -- also register functions above in the central string class for convenience
348 string.escape = escape
349 string.pcdata = pcdata
350 string.striptags = striptags
353 string.cmatch = cmatch
354 string.parse_units = parse_units
357 --- Appends numerically indexed tables or single objects to a given table.
358 -- @param src Target table
359 -- @param ... Objects to insert
360 -- @return Target table
361 function append(src, ...)
362 for i, a in ipairs({...}) do
363 if type(a) == "table" then
364 for j, v in ipairs(a) do
374 --- Combines two or more numerically indexed tables and single objects into one table.
375 -- @param tbl1 Table value to combine
376 -- @param tbl2 Table value to combine
377 -- @param ... More tables to combine
378 -- @return Table value containing all values of given tables
379 function combine(...)
380 return append({}, ...)
383 --- Checks whether the given table contains the given value.
384 -- @param table Table value
385 -- @param value Value to search within the given table
386 -- @return Boolean indicating whether the given value occurs within table
387 function contains(table, value)
388 for k, v in pairs(table) do
396 --- Update values in given table with the values from the second given table.
397 -- Both table are - in fact - merged together.
398 -- @param t Table which should be updated
399 -- @param updates Table containing the values to update
400 -- @return Always nil
401 function update(t, updates)
402 for k, v in pairs(updates) do
407 --- Retrieve all keys of given associative table.
408 -- @param t Table to extract keys from
409 -- @return Sorted table containing the keys
413 for k, _ in kspairs(t) do
420 --- Clones the given object and return it's copy.
421 -- @param object Table value to clone
422 -- @param deep Boolean indicating whether to do recursive cloning
423 -- @return Cloned table value
424 function clone(object, deep)
427 for k, v in pairs(object) do
428 if deep and type(v) == "table" then
434 return setmetatable(copy, getmetatable(object))
438 --- Create a dynamic table which automatically creates subtables.
439 -- @return Dynamic Table
441 return setmetatable({}, { __index =
443 return rawget(tbl, key)
444 or rawget(rawset(tbl, key, dtable()), key)
450 -- Serialize the contents of a table value.
451 function _serialize_table(t, seen)
452 assert(not seen[t], "Recursion detected.")
459 for k, v in pairs(t) do
460 if type(k) ~= "number" or k < 1 or math.floor(k) ~= k or ( k - #t ) > 3 then
461 k = serialize_data(k, seen)
462 v = serialize_data(v, seen)
463 data = data .. ( #data > 0 and ", " or "" ) ..
464 '[' .. k .. '] = ' .. v
471 local v = serialize_data(t[i], seen)
472 idata = idata .. ( #idata > 0 and ", " or "" ) .. v
475 return idata .. ( #data > 0 and #idata > 0 and ", " or "" ) .. data
478 --- Recursively serialize given data to lua code, suitable for restoring
479 -- with loadstring().
480 -- @param val Value containing the data to serialize
481 -- @return String value containing the serialized code
484 function serialize_data(val, seen)
485 seen = seen or setmetatable({}, {__mode="k"})
489 elseif type(val) == "number" then
491 elseif type(val) == "string" then
493 elseif type(val) == "boolean" then
494 return val and "true" or "false"
495 elseif type(val) == "function" then
496 return "loadstring(%q)" % get_bytecode(val)
497 elseif type(val) == "table" then
498 return "{ " .. _serialize_table(val, seen) .. " }"
500 return '"[unhandled data type:' .. type(val) .. ']"'
504 --- Restore data previously serialized with serialize_data().
505 -- @param str String containing the data to restore
506 -- @return Value containing the restored data structure
507 -- @see serialize_data
509 function restore_data(str)
510 return loadstring("return " .. str)()
515 -- Byte code manipulation routines
518 --- Return the current runtime bytecode of the given data. The byte code
519 -- will be stripped before it is returned.
520 -- @param val Value to return as bytecode
521 -- @return String value containing the bytecode of the given data
522 function get_bytecode(val)
525 if type(val) == "function" then
526 code = string.dump(val)
528 code = string.dump( loadstring( "return " .. serialize_data(val) ) )
531 return code and strip_bytecode(code)
534 --- Strips unnescessary lua bytecode from given string. Information like line
535 -- numbers and debugging numbers will be discarded. Original version by
536 -- Peter Cawley (http://lua-users.org/lists/lua-l/2008-02/msg01158.html)
537 -- @param code String value containing the original lua byte code
538 -- @return String value containing the stripped lua byte code
539 function strip_bytecode(code)
540 local version, format, endian, int, size, ins, num, lnum = code:byte(5, 12)
543 subint = function(code, i, l)
546 val = val * 256 + code:byte(i + n - 1)
551 subint = function(code, i, l)
554 val = val * 256 + code:byte(i + n - 1)
561 strip_function = function(code)
562 local count, offset = subint(code, 1, size)
563 local stripped, dirty = string.rep("\0", size), offset + count
564 offset = offset + count + int * 2 + 4
565 offset = offset + int + subint(code, offset, int) * ins
566 count, offset = subint(code, offset, int)
569 t, offset = subint(code, offset, 1)
573 offset = offset + size + subint(code, offset, size)
575 offset = offset + num
576 elseif t == 254 or t == 9 then
577 offset = offset + lnum
580 count, offset = subint(code, offset, int)
581 stripped = stripped .. code:sub(dirty, offset - 1)
583 local proto, off = strip_function(code:sub(offset, -1))
584 stripped, offset = stripped .. proto, offset + off - 1
586 offset = offset + subint(code, offset, int) * int + int
587 count, offset = subint(code, offset, int)
589 offset = offset + subint(code, offset, size) + size + int * 2
591 count, offset = subint(code, offset, int)
593 offset = offset + subint(code, offset, size) + size
595 stripped = stripped .. string.rep("\0", int * 3)
596 return stripped, offset
599 return code:sub(1,12) .. strip_function(code:sub(13,-1))
604 -- Sorting iterator functions
607 function _sortiter( t, f )
610 for k, v in pairs(t) do
616 table.sort( keys, f )
620 if _pos <= #keys then
621 return keys[_pos], t[keys[_pos]]
626 --- Return a key, value iterator which returns the values sorted according to
627 -- the provided callback function.
628 -- @param t The table to iterate
629 -- @param f A callback function to decide the order of elements
630 -- @return Function value containing the corresponding iterator
632 return _sortiter( t, f )
635 --- Return a key, value iterator for the given table.
636 -- The table pairs are sorted by key.
637 -- @param t The table to iterate
638 -- @return Function value containing the corresponding iterator
640 return _sortiter( t )
643 --- Return a key, value iterator for the given table.
644 -- The table pairs are sorted by value.
645 -- @param t The table to iterate
646 -- @return Function value containing the corresponding iterator
648 return _sortiter( t, function (a,b) return t[a] < t[b] end )
653 -- System utility functions
656 --- Test whether the current system is operating in big endian mode.
657 -- @return Boolean value indicating whether system is big endian
659 return string.byte(string.dump(function() end), 7) == 0
662 --- Execute given commandline and gather stdout.
663 -- @param command String containing command to execute
664 -- @return String containing the command's stdout
665 function exec(command)
666 local pp = io.popen(command)
667 local data = pp:read("*a")
673 --- Return a line-buffered iterator over the output of given command.
674 -- @param command String containing the command to execute
676 function execi(command)
677 local pp = io.popen(command)
679 return pp and function()
680 local line = pp:read()
691 function execl(command)
692 local pp = io.popen(command)
698 if (line == nil) then break end
706 --- Returns the absolute path to LuCI base directory.
707 -- @return String containing the directory path
709 return require "luci.fs".dirname(ldebug.__file__)
714 -- Coroutine safe xpcall and pcall versions modified for Luci
716 -- coxpcall 1.13 - Copyright 2005 - Kepler Project (www.keplerproject.org)
718 -- Copyright © 2005 Kepler Project.
719 -- Permission is hereby granted, free of charge, to any person obtaining a
720 -- copy of this software and associated documentation files (the "Software"),
721 -- to deal in the Software without restriction, including without limitation
722 -- the rights to use, copy, modify, merge, publish, distribute, sublicense,
723 -- and/or sell copies of the Software, and to permit persons to whom the
724 -- Software is furnished to do so, subject to the following conditions:
726 -- The above copyright notice and this permission notice shall be
727 -- included in all copies or substantial portions of the Software.
729 -- THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
730 -- EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
731 -- OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
732 -- IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
733 -- DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
734 -- TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE
735 -- OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
737 local performResume, handleReturnValue
738 local oldpcall, oldxpcall = pcall, xpcall
740 setmetatable(coxpt, {__mode = "kv"})
742 -- Identity function for copcall
743 local function copcall_id(trace, ...)
747 --- This is a coroutine-safe drop-in replacement for Lua's "xpcall"-function
748 -- @param f Lua function to be called protected
749 -- @param err Custom error handler
750 -- @param ... Parameters passed to the function
751 -- @return A boolean whether the function call succeeded and the return
752 -- values of either the function or the error handler
753 function coxpcall(f, err, ...)
754 local res, co = oldpcall(coroutine.create, f)
757 local newf = function() return f(unpack(params)) end
758 co = coroutine.create(newf)
760 local c = coroutine.running()
761 coxpt[co] = coxpt[c] or c or 0
763 return performResume(err, co, ...)
766 --- This is a coroutine-safe drop-in replacement for Lua's "pcall"-function
767 -- @param f Lua function to be called protected
768 -- @param ... Parameters passed to the function
769 -- @return A boolean whether the function call succeeded and the returns
770 -- values of the function or the error object
771 function copcall(f, ...)
772 return coxpcall(f, copcall_id, ...)
775 -- Handle return value of protected call
776 function handleReturnValue(err, co, status, ...)
778 return false, err(debug.traceback(co, (...)), ...)
780 if coroutine.status(co) == 'suspended' then
781 return performResume(err, co, coroutine.yield(...))
787 -- Resume execution of protected function call
788 function performResume(err, co, ...)
789 return handleReturnValue(err, co, coroutine.resume(co, ...))