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 function pcdata(value)
197 return value and tostring(value):gsub("[&\"'<>]", {
206 --- Strip HTML tags from given string.
207 -- @param value String containing the HTML text
208 -- @return String with HTML tags stripped of
209 function striptags(s)
210 return pcdata(s:gsub("</?[A-Za-z][A-Za-z0-9:_%-]*[^>]*>", " "):gsub("%s+", " "))
213 --- Splits given string on a defined separator sequence and return a table
214 -- containing the resulting substrings. The optional max parameter specifies
215 -- the number of bytes to process, regardless of the actual length of the given
216 -- string. The optional last parameter, regex, specifies whether the separator
217 -- sequence is interpreted as regular expression.
218 -- @param str String value containing the data to split up
219 -- @param pat String with separator pattern (optional, defaults to "\n")
220 -- @param max Maximum times to split (optional)
221 -- @param regex Boolean indicating whether to interpret the separator
222 -- pattern as regular expression (optional, default is false)
223 -- @return Table containing the resulting substrings
224 function split(str, pat, max, regex)
244 local s, e = str:find(pat, c, not regex)
246 if s and max < 0 then
249 t[#t+1] = str:sub(c, s and s - 1)
251 c = e and e + 1 or #str + 1
252 until not s or max < 0
257 --- Remove leading and trailing whitespace from given string value.
258 -- @param str String value containing whitespace padded data
259 -- @return String value with leading and trailing space removed
261 return (str:gsub("^%s*(.-)%s*$", "%1"))
264 --- Parse certain units from the given string and return the canonical integer
265 -- value or 0 if the unit is unknown. Upper- or lower case is irrelevant.
266 -- Recognized units are:
267 -- o "y" - one year (60*60*24*366)
268 -- o "m" - one month (60*60*24*31)
269 -- o "w" - one week (60*60*24*7)
270 -- o "d" - one day (60*60*24)
271 -- o "h" - one hour (60*60)
272 -- o "min" - one minute (60)
273 -- o "kb" - one kilobyte (1024)
274 -- o "mb" - one megabyte (1024*1024)
275 -- o "gb" - one gigabyte (1024*1024*1024)
276 -- o "kib" - one si kilobyte (1000)
277 -- o "mib" - one si megabyte (1000*1000)
278 -- o "gib" - one si gigabyte (1000*1000*1000)
279 -- @param ustr String containing a numerical value with trailing unit
280 -- @return Number containing the canonical value
281 function parse_units(ustr)
288 y = 60 * 60 * 24 * 366,
289 m = 60 * 60 * 24 * 31,
290 w = 60 * 60 * 24 * 7,
298 gb = 1024 * 1024 * 1024,
300 -- storage sizes (si)
303 gib = 1000 * 1000 * 1000
306 -- parse input string
307 for spec in ustr:lower():gmatch("[0-9%.]+[a-zA-Z]*") do
309 local num = spec:gsub("[^0-9%.]+$","")
310 local spn = spec:gsub("^[0-9%.]+", "")
312 if map[spn] or map[spn:sub(1,1)] then
313 val = val + num * ( map[spn] or map[spn:sub(1,1)] )
323 --- Appends numerically indexed tables or single objects to a given table.
324 -- @param src Target table
325 -- @param ... Objects to insert
326 -- @return Target table
327 function append(src, ...)
328 for i, a in ipairs({...}) do
329 if type(a) == "table" then
330 for j, v in ipairs(a) do
340 --- Combines two or more numerically indexed tables and single objects into one table.
341 -- @param tbl1 Table value to combine
342 -- @param tbl2 Table value to combine
343 -- @param ... More tables to combine
344 -- @return Table value containing all values of given tables
345 function combine(...)
346 return append({}, ...)
349 --- Checks whether the given table contains the given value.
350 -- @param table Table value
351 -- @param value Value to search within the given table
352 -- @return Boolean indicating whether the given value occurs within table
353 function contains(table, value)
354 for k, v in pairs(table) do
362 --- Update values in given table with the values from the second given table.
363 -- Both table are - in fact - merged together.
364 -- @param t Table which should be updated
365 -- @param updates Table containing the values to update
366 -- @return Always nil
367 function update(t, updates)
368 for k, v in pairs(updates) do
373 --- Retrieve all keys of given associative table.
374 -- @param t Table to extract keys from
375 -- @return Sorted table containing the keys
379 for k, _ in kspairs(t) do
386 --- Clones the given object and return it's copy.
387 -- @param object Table value to clone
388 -- @param deep Boolean indicating whether to do recursive cloning
389 -- @return Cloned table value
390 function clone(object, deep)
393 for k, v in pairs(object) do
394 if deep and type(v) == "table" then
400 return setmetatable(copy, getmetatable(object))
404 --- Create a dynamic table which automatically creates subtables.
405 -- @return Dynamic Table
407 return setmetatable({}, { __index =
409 return rawget(tbl, key)
410 or rawget(rawset(tbl, key, dtable()), key)
416 -- Serialize the contents of a table value.
417 function _serialize_table(t, seen)
418 assert(not seen[t], "Recursion detected.")
425 for k, v in pairs(t) do
426 if type(k) ~= "number" or k < 1 or math.floor(k) ~= k or ( k - #t ) > 3 then
427 k = serialize_data(k, seen)
428 v = serialize_data(v, seen)
429 data = data .. ( #data > 0 and ", " or "" ) ..
430 '[' .. k .. '] = ' .. v
437 local v = serialize_data(t[i], seen)
438 idata = idata .. ( #idata > 0 and ", " or "" ) .. v
441 return idata .. ( #data > 0 and #idata > 0 and ", " or "" ) .. data
444 --- Recursively serialize given data to lua code, suitable for restoring
445 -- with loadstring().
446 -- @param val Value containing the data to serialize
447 -- @return String value containing the serialized code
450 function serialize_data(val, seen)
451 seen = seen or setmetatable({}, {__mode="k"})
455 elseif type(val) == "number" then
457 elseif type(val) == "string" then
459 elseif type(val) == "boolean" then
460 return val and "true" or "false"
461 elseif type(val) == "function" then
462 return "loadstring(%q)" % get_bytecode(val)
463 elseif type(val) == "table" then
464 return "{ " .. _serialize_table(val, seen) .. " }"
466 return '"[unhandled data type:' .. type(val) .. ']"'
470 --- Restore data previously serialized with serialize_data().
471 -- @param str String containing the data to restore
472 -- @return Value containing the restored data structure
473 -- @see serialize_data
475 function restore_data(str)
476 return loadstring("return " .. str)()
481 -- Byte code manipulation routines
484 --- Return the current runtime bytecode of the given data. The byte code
485 -- will be stripped before it is returned.
486 -- @param val Value to return as bytecode
487 -- @return String value containing the bytecode of the given data
488 function get_bytecode(val)
491 if type(val) == "function" then
492 code = string.dump(val)
494 code = string.dump( loadstring( "return " .. serialize_data(val) ) )
497 return code and strip_bytecode(code)
500 --- Strips unnescessary lua bytecode from given string. Information like line
501 -- numbers and debugging numbers will be discarded. Original version by
502 -- Peter Cawley (http://lua-users.org/lists/lua-l/2008-02/msg01158.html)
503 -- @param code String value containing the original lua byte code
504 -- @return String value containing the stripped lua byte code
505 function strip_bytecode(code)
506 local version, format, endian, int, size, ins, num, lnum = code:byte(5, 12)
509 subint = function(code, i, l)
512 val = val * 256 + code:byte(i + n - 1)
517 subint = function(code, i, l)
520 val = val * 256 + code:byte(i + n - 1)
527 strip_function = function(code)
528 local count, offset = subint(code, 1, size)
529 local stripped, dirty = string.rep("\0", size), offset + count
530 offset = offset + count + int * 2 + 4
531 offset = offset + int + subint(code, offset, int) * ins
532 count, offset = subint(code, offset, int)
535 t, offset = subint(code, offset, 1)
539 offset = offset + size + subint(code, offset, size)
541 offset = offset + num
542 elseif t == 254 or t == 9 then
543 offset = offset + lnum
546 count, offset = subint(code, offset, int)
547 stripped = stripped .. code:sub(dirty, offset - 1)
549 local proto, off = strip_function(code:sub(offset, -1))
550 stripped, offset = stripped .. proto, offset + off - 1
552 offset = offset + subint(code, offset, int) * int + int
553 count, offset = subint(code, offset, int)
555 offset = offset + subint(code, offset, size) + size + int * 2
557 count, offset = subint(code, offset, int)
559 offset = offset + subint(code, offset, size) + size
561 stripped = stripped .. string.rep("\0", int * 3)
562 return stripped, offset
565 return code:sub(1,12) .. strip_function(code:sub(13,-1))
570 -- Sorting iterator functions
573 function _sortiter( t, f )
576 for k, v in pairs(t) do
582 table.sort( keys, f )
586 if _pos <= #keys then
587 return keys[_pos], t[keys[_pos]]
592 --- Return a key, value iterator which returns the values sorted according to
593 -- the provided callback function.
594 -- @param t The table to iterate
595 -- @param f A callback function to decide the order of elements
596 -- @return Function value containing the corresponding iterator
598 return _sortiter( t, f )
601 --- Return a key, value iterator for the given table.
602 -- The table pairs are sorted by key.
603 -- @param t The table to iterate
604 -- @return Function value containing the corresponding iterator
606 return _sortiter( t )
609 --- Return a key, value iterator for the given table.
610 -- The table pairs are sorted by value.
611 -- @param t The table to iterate
612 -- @return Function value containing the corresponding iterator
614 return _sortiter( t, function (a,b) return t[a] < t[b] end )
619 -- System utility functions
622 --- Test whether the current system is operating in big endian mode.
623 -- @return Boolean value indicating whether system is big endian
625 return string.byte(string.dump(function() end), 7) == 0
628 --- Execute given commandline and gather stdout.
629 -- @param command String containing command to execute
630 -- @return String containing the command's stdout
631 function exec(command)
632 local pp = io.popen(command)
633 local data = pp:read("*a")
639 --- Return a line-buffered iterator over the output of given command.
640 -- @param command String containing the command to execute
642 function execi(command)
643 local pp = io.popen(command)
645 return pp and function()
646 local line = pp:read()
657 function execl(command)
658 local pp = io.popen(command)
664 if (line == nil) then break end
672 --- Returns the absolute path to LuCI base directory.
673 -- @return String containing the directory path
675 return require "luci.fs".dirname(ldebug.__file__)
680 -- Coroutine safe xpcall and pcall versions modified for Luci
682 -- coxpcall 1.13 - Copyright 2005 - Kepler Project (www.keplerproject.org)
684 -- Copyright © 2005 Kepler Project.
685 -- Permission is hereby granted, free of charge, to any person obtaining a
686 -- copy of this software and associated documentation files (the "Software"),
687 -- to deal in the Software without restriction, including without limitation
688 -- the rights to use, copy, modify, merge, publish, distribute, sublicense,
689 -- and/or sell copies of the Software, and to permit persons to whom the
690 -- Software is furnished to do so, subject to the following conditions:
692 -- The above copyright notice and this permission notice shall be
693 -- included in all copies or substantial portions of the Software.
695 -- THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
696 -- EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
697 -- OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
698 -- IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
699 -- DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
700 -- TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE
701 -- OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
703 local performResume, handleReturnValue
704 local oldpcall, oldxpcall = pcall, xpcall
706 setmetatable(coxpt, {__mode = "kv"})
708 -- Identity function for copcall
709 local function copcall_id(trace, ...)
713 --- This is a coroutine-safe drop-in replacement for Lua's "xpcall"-function
714 -- @param f Lua function to be called protected
715 -- @param err Custom error handler
716 -- @param ... Parameters passed to the function
717 -- @return A boolean whether the function call succeeded and the return
718 -- values of either the function or the error handler
719 function coxpcall(f, err, ...)
720 local res, co = oldpcall(coroutine.create, f)
723 local newf = function() return f(unpack(params)) end
724 co = coroutine.create(newf)
726 local c = coroutine.running()
727 coxpt[co] = coxpt[c] or c or 0
729 return performResume(err, co, ...)
732 --- This is a coroutine-safe drop-in replacement for Lua's "pcall"-function
733 -- @param f Lua function to be called protected
734 -- @param ... Parameters passed to the function
735 -- @return A boolean whether the function call succeeded and the returns
736 -- values of the function or the error object
737 function copcall(f, ...)
738 return coxpcall(f, copcall_id, ...)
741 -- Handle return value of protected call
742 function handleReturnValue(err, co, status, ...)
744 return false, err(debug.traceback(co, (...)), ...)
746 if coroutine.status(co) == 'suspended' then
747 return performResume(err, co, coroutine.yield(...))
753 -- Resume execution of protected function call
754 function performResume(err, co, ...)
755 return handleReturnValue(err, co, coroutine.resume(co, ...))