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"
35 local getmetatable, setmetatable = getmetatable, setmetatable
36 local rawget, rawset, unpack = rawget, rawset, unpack
37 local tostring, type, assert = tostring, type, assert
38 local ipairs, pairs, loadstring = ipairs, pairs, loadstring
39 local require, pcall, xpcall = require, pcall, xpcall
41 --- LuCI utility functions.
45 -- Pythonic string formatting extension
47 getmetatable("").__mod = function(a, b)
50 elseif type(b) == "table" then
51 return a:format(unpack(b))
59 -- Class helper routines
62 -- Instantiates a class
63 local function _instantiate(class, ...)
64 local inst = setmetatable({}, {__index = class})
73 --- Create a Class object (Python-style object model).
74 -- The class object can be instantiated by calling itself.
75 -- Any class functions or shared parameters can be attached to this object.
76 -- Attaching a table to the class object makes this table shared between
77 -- all instances of this class. For object parameters use the __init__ function.
78 -- Classes can inherit member functions and values from a base class.
79 -- Class can be instantiated by calling them. All parameters will be passed
80 -- to the __init__ function of this class - if such a function exists.
81 -- The __init__ function must be used to set any object parameters that are not shared
82 -- with other objects of this class. Any return values will be ignored.
83 -- @param base The base class to inherit from (optional)
84 -- @return A class object
88 return setmetatable({}, {
89 __call = _instantiate,
94 --- Test whether the given object is an instance of the given class.
95 -- @param object Object instance
96 -- @param class Class object to test against
97 -- @return Boolean indicating whether the object is an instance
100 function instanceof(object, class)
101 local meta = getmetatable(object)
102 while meta and meta.__index do
103 if meta.__index == class then
106 meta = getmetatable(meta.__index)
113 -- Scope manipulation routines
116 --- Create a new or get an already existing thread local store associated with
117 -- the current active coroutine. A thread local store is private a table object
118 -- whose values can't be accessed from outside of the running coroutine.
119 -- @return Table value representing the corresponding thread local store
120 function threadlocal()
123 local function get(self, key)
124 local c = coroutine.running()
125 local thread = coxpt[c] or c or 0
126 if not rawget(self, thread) then
129 return rawget(self, thread)[key]
132 local function set(self, key, value)
133 local c = coroutine.running()
134 local thread = coxpt[c] or c or 0
135 if not rawget(self, thread) then
136 rawset(self, thread, {})
138 rawget(self, thread)[key] = value
141 setmetatable(tbl, {__index = get, __newindex = set, __mode = "k"})
148 -- Debugging routines
151 --- Write given object to stderr.
152 -- @param obj Value to write to stderr
153 -- @return Boolean indicating whether the write operation was successful
155 return io.stderr:write(tostring(obj) .. "\n")
158 --- Recursively dumps a table to stdout, useful for testing and debugging.
159 -- @param t Table value to dump
160 -- @param maxdepth Maximum depth
161 -- @return Always nil
162 function dumptable(t, maxdepth, i, seen)
164 seen = seen or setmetatable({}, {__mode="k"})
166 for k,v in pairs(t) do
167 perror(string.rep("\t", i) .. tostring(k) .. "\t" .. tostring(v))
168 if type(v) == "table" and (not maxdepth or i < maxdepth) then
171 dumptable(v, maxdepth, i+1, seen)
173 perror(string.rep("\t", i) .. "*** RECURSION ***")
181 -- String and data manipulation routines
184 --- Escapes all occurrences of the given character in given string.
185 -- @param s String value containing unescaped characters
186 -- @param c String value with character to escape (optional, defaults to "\")
187 -- @return String value with each occurrence of character escaped with "\"
188 function escape(s, c)
190 return s:gsub(c, "\\" .. c)
193 --- Create valid XML PCDATA from given string.
194 -- @param value String value containing the data to escape
195 -- @return String value containing the escaped data
196 local _pcdata_repl = {
204 function pcdata(value)
205 return value and tostring(value):gsub("[&\"'<>]", _pcdata_repl)
208 --- Strip HTML tags from given string.
209 -- @param value String containing the HTML text
210 -- @return String with HTML tags stripped of
211 function striptags(s)
212 return pcdata(s:gsub("</?[A-Za-z][A-Za-z0-9:_%-]*[^>]*>", " "):gsub("%s+", " "))
215 --- Splits given string on a defined separator sequence and return a table
216 -- containing the resulting substrings. The optional max parameter specifies
217 -- the number of bytes to process, regardless of the actual length of the given
218 -- string. The optional last parameter, regex, specifies whether the separator
219 -- sequence is interpreted as regular expression.
220 -- @param str String value containing the data to split up
221 -- @param pat String with separator pattern (optional, defaults to "\n")
222 -- @param max Maximum times to split (optional)
223 -- @param regex Boolean indicating whether to interpret the separator
224 -- pattern as regular expression (optional, default is false)
225 -- @return Table containing the resulting substrings
226 function split(str, pat, max, regex)
246 local s, e = str:find(pat, c, not regex)
248 if s and max < 0 then
251 t[#t+1] = str:sub(c, s and s - 1)
253 c = e and e + 1 or #str + 1
254 until not s or max < 0
259 --- Remove leading and trailing whitespace from given string value.
260 -- @param str String value containing whitespace padded data
261 -- @return String value with leading and trailing space removed
263 return (str:gsub("^%s*(.-)%s*$", "%1"))
266 --- Count the occurences of given substring in given string.
267 -- @param str String to search in
268 -- @param pattern String containing pattern to find
269 -- @return Number of found occurences
270 function cmatch(str, pat)
272 for _ in str:gmatch(pat) do count = count + 1 end
276 --- Parse certain units from the given string and return the canonical integer
277 -- value or 0 if the unit is unknown. Upper- or lower case is irrelevant.
278 -- Recognized units are:
279 -- o "y" - one year (60*60*24*366)
280 -- o "m" - one month (60*60*24*31)
281 -- o "w" - one week (60*60*24*7)
282 -- o "d" - one day (60*60*24)
283 -- o "h" - one hour (60*60)
284 -- o "min" - one minute (60)
285 -- o "kb" - one kilobyte (1024)
286 -- o "mb" - one megabyte (1024*1024)
287 -- o "gb" - one gigabyte (1024*1024*1024)
288 -- o "kib" - one si kilobyte (1000)
289 -- o "mib" - one si megabyte (1000*1000)
290 -- o "gib" - one si gigabyte (1000*1000*1000)
291 -- @param ustr String containing a numerical value with trailing unit
292 -- @return Number containing the canonical value
293 function parse_units(ustr)
300 y = 60 * 60 * 24 * 366,
301 m = 60 * 60 * 24 * 31,
302 w = 60 * 60 * 24 * 7,
310 gb = 1024 * 1024 * 1024,
312 -- storage sizes (si)
315 gib = 1000 * 1000 * 1000
318 -- parse input string
319 for spec in ustr:lower():gmatch("[0-9%.]+[a-zA-Z]*") do
321 local num = spec:gsub("[^0-9%.]+$","")
322 local spn = spec:gsub("^[0-9%.]+", "")
324 if map[spn] or map[spn:sub(1,1)] then
325 val = val + num * ( map[spn] or map[spn:sub(1,1)] )
335 -- also register functions above in the central string class for convenience
336 string.escape = escape
337 string.pcdata = pcdata
338 string.striptags = striptags
341 string.cmatch = cmatch
342 string.parse_units = parse_units
345 --- Appends numerically indexed tables or single objects to a given table.
346 -- @param src Target table
347 -- @param ... Objects to insert
348 -- @return Target table
349 function append(src, ...)
350 for i, a in ipairs({...}) do
351 if type(a) == "table" then
352 for j, v in ipairs(a) do
362 --- Combines two or more numerically indexed tables and single objects into one table.
363 -- @param tbl1 Table value to combine
364 -- @param tbl2 Table value to combine
365 -- @param ... More tables to combine
366 -- @return Table value containing all values of given tables
367 function combine(...)
368 return append({}, ...)
371 --- Checks whether the given table contains the given value.
372 -- @param table Table value
373 -- @param value Value to search within the given table
374 -- @return Boolean indicating whether the given value occurs within table
375 function contains(table, value)
376 for k, v in pairs(table) do
384 --- Update values in given table with the values from the second given table.
385 -- Both table are - in fact - merged together.
386 -- @param t Table which should be updated
387 -- @param updates Table containing the values to update
388 -- @return Always nil
389 function update(t, updates)
390 for k, v in pairs(updates) do
395 --- Retrieve all keys of given associative table.
396 -- @param t Table to extract keys from
397 -- @return Sorted table containing the keys
401 for k, _ in kspairs(t) do
408 --- Clones the given object and return it's copy.
409 -- @param object Table value to clone
410 -- @param deep Boolean indicating whether to do recursive cloning
411 -- @return Cloned table value
412 function clone(object, deep)
415 for k, v in pairs(object) do
416 if deep and type(v) == "table" then
422 return setmetatable(copy, getmetatable(object))
426 --- Create a dynamic table which automatically creates subtables.
427 -- @return Dynamic Table
429 return setmetatable({}, { __index =
431 return rawget(tbl, key)
432 or rawget(rawset(tbl, key, dtable()), key)
438 -- Serialize the contents of a table value.
439 function _serialize_table(t, seen)
440 assert(not seen[t], "Recursion detected.")
447 for k, v in pairs(t) do
448 if type(k) ~= "number" or k < 1 or math.floor(k) ~= k or ( k - #t ) > 3 then
449 k = serialize_data(k, seen)
450 v = serialize_data(v, seen)
451 data = data .. ( #data > 0 and ", " or "" ) ..
452 '[' .. k .. '] = ' .. v
459 local v = serialize_data(t[i], seen)
460 idata = idata .. ( #idata > 0 and ", " or "" ) .. v
463 return idata .. ( #data > 0 and #idata > 0 and ", " or "" ) .. data
466 --- Recursively serialize given data to lua code, suitable for restoring
467 -- with loadstring().
468 -- @param val Value containing the data to serialize
469 -- @return String value containing the serialized code
472 function serialize_data(val, seen)
473 seen = seen or setmetatable({}, {__mode="k"})
477 elseif type(val) == "number" then
479 elseif type(val) == "string" then
481 elseif type(val) == "boolean" then
482 return val and "true" or "false"
483 elseif type(val) == "function" then
484 return "loadstring(%q)" % get_bytecode(val)
485 elseif type(val) == "table" then
486 return "{ " .. _serialize_table(val, seen) .. " }"
488 return '"[unhandled data type:' .. type(val) .. ']"'
492 --- Restore data previously serialized with serialize_data().
493 -- @param str String containing the data to restore
494 -- @return Value containing the restored data structure
495 -- @see serialize_data
497 function restore_data(str)
498 return loadstring("return " .. str)()
503 -- Byte code manipulation routines
506 --- Return the current runtime bytecode of the given data. The byte code
507 -- will be stripped before it is returned.
508 -- @param val Value to return as bytecode
509 -- @return String value containing the bytecode of the given data
510 function get_bytecode(val)
513 if type(val) == "function" then
514 code = string.dump(val)
516 code = string.dump( loadstring( "return " .. serialize_data(val) ) )
519 return code and strip_bytecode(code)
522 --- Strips unnescessary lua bytecode from given string. Information like line
523 -- numbers and debugging numbers will be discarded. Original version by
524 -- Peter Cawley (http://lua-users.org/lists/lua-l/2008-02/msg01158.html)
525 -- @param code String value containing the original lua byte code
526 -- @return String value containing the stripped lua byte code
527 function strip_bytecode(code)
528 local version, format, endian, int, size, ins, num, lnum = code:byte(5, 12)
531 subint = function(code, i, l)
534 val = val * 256 + code:byte(i + n - 1)
539 subint = function(code, i, l)
542 val = val * 256 + code:byte(i + n - 1)
549 strip_function = function(code)
550 local count, offset = subint(code, 1, size)
551 local stripped, dirty = string.rep("\0", size), offset + count
552 offset = offset + count + int * 2 + 4
553 offset = offset + int + subint(code, offset, int) * ins
554 count, offset = subint(code, offset, int)
557 t, offset = subint(code, offset, 1)
561 offset = offset + size + subint(code, offset, size)
563 offset = offset + num
564 elseif t == 254 or t == 9 then
565 offset = offset + lnum
568 count, offset = subint(code, offset, int)
569 stripped = stripped .. code:sub(dirty, offset - 1)
571 local proto, off = strip_function(code:sub(offset, -1))
572 stripped, offset = stripped .. proto, offset + off - 1
574 offset = offset + subint(code, offset, int) * int + int
575 count, offset = subint(code, offset, int)
577 offset = offset + subint(code, offset, size) + size + int * 2
579 count, offset = subint(code, offset, int)
581 offset = offset + subint(code, offset, size) + size
583 stripped = stripped .. string.rep("\0", int * 3)
584 return stripped, offset
587 return code:sub(1,12) .. strip_function(code:sub(13,-1))
592 -- Sorting iterator functions
595 function _sortiter( t, f )
598 for k, v in pairs(t) do
604 table.sort( keys, f )
608 if _pos <= #keys then
609 return keys[_pos], t[keys[_pos]]
614 --- Return a key, value iterator which returns the values sorted according to
615 -- the provided callback function.
616 -- @param t The table to iterate
617 -- @param f A callback function to decide the order of elements
618 -- @return Function value containing the corresponding iterator
620 return _sortiter( t, f )
623 --- Return a key, value iterator for the given table.
624 -- The table pairs are sorted by key.
625 -- @param t The table to iterate
626 -- @return Function value containing the corresponding iterator
628 return _sortiter( t )
631 --- Return a key, value iterator for the given table.
632 -- The table pairs are sorted by value.
633 -- @param t The table to iterate
634 -- @return Function value containing the corresponding iterator
636 return _sortiter( t, function (a,b) return t[a] < t[b] end )
641 -- System utility functions
644 --- Test whether the current system is operating in big endian mode.
645 -- @return Boolean value indicating whether system is big endian
647 return string.byte(string.dump(function() end), 7) == 0
650 --- Execute given commandline and gather stdout.
651 -- @param command String containing command to execute
652 -- @return String containing the command's stdout
653 function exec(command)
654 local pp = io.popen(command)
655 local data = pp:read("*a")
661 --- Return a line-buffered iterator over the output of given command.
662 -- @param command String containing the command to execute
664 function execi(command)
665 local pp = io.popen(command)
667 return pp and function()
668 local line = pp:read()
679 function execl(command)
680 local pp = io.popen(command)
686 if (line == nil) then break end
694 --- Returns the absolute path to LuCI base directory.
695 -- @return String containing the directory path
697 return require "luci.fs".dirname(ldebug.__file__)
702 -- Coroutine safe xpcall and pcall versions modified for Luci
704 -- coxpcall 1.13 - Copyright 2005 - Kepler Project (www.keplerproject.org)
706 -- Copyright © 2005 Kepler Project.
707 -- Permission is hereby granted, free of charge, to any person obtaining a
708 -- copy of this software and associated documentation files (the "Software"),
709 -- to deal in the Software without restriction, including without limitation
710 -- the rights to use, copy, modify, merge, publish, distribute, sublicense,
711 -- and/or sell copies of the Software, and to permit persons to whom the
712 -- Software is furnished to do so, subject to the following conditions:
714 -- The above copyright notice and this permission notice shall be
715 -- included in all copies or substantial portions of the Software.
717 -- THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
718 -- EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
719 -- OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
720 -- IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
721 -- DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
722 -- TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE
723 -- OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
725 local performResume, handleReturnValue
726 local oldpcall, oldxpcall = pcall, xpcall
728 setmetatable(coxpt, {__mode = "kv"})
730 -- Identity function for copcall
731 local function copcall_id(trace, ...)
735 --- This is a coroutine-safe drop-in replacement for Lua's "xpcall"-function
736 -- @param f Lua function to be called protected
737 -- @param err Custom error handler
738 -- @param ... Parameters passed to the function
739 -- @return A boolean whether the function call succeeded and the return
740 -- values of either the function or the error handler
741 function coxpcall(f, err, ...)
742 local res, co = oldpcall(coroutine.create, f)
745 local newf = function() return f(unpack(params)) end
746 co = coroutine.create(newf)
748 local c = coroutine.running()
749 coxpt[co] = coxpt[c] or c or 0
751 return performResume(err, co, ...)
754 --- This is a coroutine-safe drop-in replacement for Lua's "pcall"-function
755 -- @param f Lua function to be called protected
756 -- @param ... Parameters passed to the function
757 -- @return A boolean whether the function call succeeded and the returns
758 -- values of the function or the error object
759 function copcall(f, ...)
760 return coxpcall(f, copcall_id, ...)
763 -- Handle return value of protected call
764 function handleReturnValue(err, co, status, ...)
766 return false, err(debug.traceback(co, (...)), ...)
768 if coroutine.status(co) == 'suspended' then
769 return performResume(err, co, coroutine.yield(...))
775 -- Resume execution of protected function call
776 function performResume(err, co, ...)
777 return handleReturnValue(err, co, coroutine.resume(co, ...))