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
40 local collectgarbage, get_memory_limit = collectgarbage, get_memory_limit
42 --- LuCI utility functions.
46 -- Pythonic string formatting extension
48 getmetatable("").__mod = function(a, b)
51 elseif type(b) == "table" then
52 for k, _ in pairs(b) do if type(b[k]) == "userdata" then b[k] = tostring(b[k]) end end
53 return a:format(unpack(b))
55 if type(b) == "userdata" then b = tostring(b) end
62 -- Class helper routines
65 -- Instantiates a class
66 local function _instantiate(class, ...)
67 local inst = setmetatable({}, {__index = class})
76 --- Create a Class object (Python-style object model).
77 -- The class object can be instantiated by calling itself.
78 -- Any class functions or shared parameters can be attached to this object.
79 -- Attaching a table to the class object makes this table shared between
80 -- all instances of this class. For object parameters use the __init__ function.
81 -- Classes can inherit member functions and values from a base class.
82 -- Class can be instantiated by calling them. All parameters will be passed
83 -- to the __init__ function of this class - if such a function exists.
84 -- The __init__ function must be used to set any object parameters that are not shared
85 -- with other objects of this class. Any return values will be ignored.
86 -- @param base The base class to inherit from (optional)
87 -- @return A class object
91 return setmetatable({}, {
92 __call = _instantiate,
97 --- Test whether the given object is an instance of the given class.
98 -- @param object Object instance
99 -- @param class Class object to test against
100 -- @return Boolean indicating whether the object is an instance
103 function instanceof(object, class)
104 local meta = getmetatable(object)
105 while meta and meta.__index do
106 if meta.__index == class then
109 meta = getmetatable(meta.__index)
116 -- Scope manipulation routines
122 __index = function(self, key)
123 local t = rawget(self, coxpt[coroutine.running()]
124 or coroutine.running() or 0)
128 __newindex = function(self, key, value)
129 local c = coxpt[coroutine.running()] or coroutine.running() or 0
130 if not rawget(self, c) then
131 rawset(self, c, { [key] = value })
133 rawget(self, c)[key] = value
138 --- Create a new or get an already existing thread local store associated with
139 -- the current active coroutine. A thread local store is private a table object
140 -- whose values can't be accessed from outside of the running coroutine.
141 -- @return Table value representing the corresponding thread local store
142 function threadlocal(tbl)
143 return setmetatable(tbl or {}, tl_meta)
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 function _pcdata_repl(c)
197 local i = string.byte(c)
199 if ( i >= 0x00 and i <= 0x08 ) or ( i >= 0x0B and i <= 0x0C ) or
200 ( i >= 0x0E and i <= 0x1F ) or ( i == 0x7F )
204 elseif ( i == 0x26 ) or ( i == 0x27 ) or ( i == 0x22 ) or
205 ( i == 0x3C ) or ( i == 0x3E )
207 return string.format("&#%i;", i)
213 function pcdata(value)
214 return value and tostring(value):gsub("[&\"'<>%c]", _pcdata_repl)
217 --- Strip HTML tags from given string.
218 -- @param value String containing the HTML text
219 -- @return String with HTML tags stripped of
220 function striptags(s)
221 return pcdata(tostring(s):gsub("</?[A-Za-z][A-Za-z0-9:_%-]*[^>]*>", " "):gsub("%s+", " "))
224 --- Splits given string on a defined separator sequence and return a table
225 -- containing the resulting substrings. The optional max parameter specifies
226 -- the number of bytes to process, regardless of the actual length of the given
227 -- string. The optional last parameter, regex, specifies whether the separator
228 -- sequence is interpreted as regular expression.
229 -- @param str String value containing the data to split up
230 -- @param pat String with separator pattern (optional, defaults to "\n")
231 -- @param max Maximum times to split (optional)
232 -- @param regex Boolean indicating whether to interpret the separator
233 -- pattern as regular expression (optional, default is false)
234 -- @return Table containing the resulting substrings
235 function split(str, pat, max, regex)
255 local s, e = str:find(pat, c, not regex)
257 if s and max < 0 then
260 t[#t+1] = str:sub(c, s and s - 1)
262 c = e and e + 1 or #str + 1
263 until not s or max < 0
268 --- Remove leading and trailing whitespace from given string value.
269 -- @param str String value containing whitespace padded data
270 -- @return String value with leading and trailing space removed
272 return (str:gsub("^%s*(.-)%s*$", "%1"))
275 --- Count the occurences of given substring in given string.
276 -- @param str String to search in
277 -- @param pattern String containing pattern to find
278 -- @return Number of found occurences
279 function cmatch(str, pat)
281 for _ in str:gmatch(pat) do count = count + 1 end
285 --- Parse certain units from the given string and return the canonical integer
286 -- value or 0 if the unit is unknown. Upper- or lower case is irrelevant.
287 -- Recognized units are:
288 -- o "y" - one year (60*60*24*366)
289 -- o "m" - one month (60*60*24*31)
290 -- o "w" - one week (60*60*24*7)
291 -- o "d" - one day (60*60*24)
292 -- o "h" - one hour (60*60)
293 -- o "min" - one minute (60)
294 -- o "kb" - one kilobyte (1024)
295 -- o "mb" - one megabyte (1024*1024)
296 -- o "gb" - one gigabyte (1024*1024*1024)
297 -- o "kib" - one si kilobyte (1000)
298 -- o "mib" - one si megabyte (1000*1000)
299 -- o "gib" - one si gigabyte (1000*1000*1000)
300 -- @param ustr String containing a numerical value with trailing unit
301 -- @return Number containing the canonical value
302 function parse_units(ustr)
309 y = 60 * 60 * 24 * 366,
310 m = 60 * 60 * 24 * 31,
311 w = 60 * 60 * 24 * 7,
319 gb = 1024 * 1024 * 1024,
321 -- storage sizes (si)
324 gib = 1000 * 1000 * 1000
327 -- parse input string
328 for spec in ustr:lower():gmatch("[0-9%.]+[a-zA-Z]*") do
330 local num = spec:gsub("[^0-9%.]+$","")
331 local spn = spec:gsub("^[0-9%.]+", "")
333 if map[spn] or map[spn:sub(1,1)] then
334 val = val + num * ( map[spn] or map[spn:sub(1,1)] )
344 -- also register functions above in the central string class for convenience
345 string.escape = escape
346 string.pcdata = pcdata
347 string.striptags = striptags
350 string.cmatch = cmatch
351 string.parse_units = parse_units
354 --- Appends numerically indexed tables or single objects to a given table.
355 -- @param src Target table
356 -- @param ... Objects to insert
357 -- @return Target table
358 function append(src, ...)
359 for i, a in ipairs({...}) do
360 if type(a) == "table" then
361 for j, v in ipairs(a) do
371 --- Combines two or more numerically indexed tables and single objects into one table.
372 -- @param tbl1 Table value to combine
373 -- @param tbl2 Table value to combine
374 -- @param ... More tables to combine
375 -- @return Table value containing all values of given tables
376 function combine(...)
377 return append({}, ...)
380 --- Checks whether the given table contains the given value.
381 -- @param table Table value
382 -- @param value Value to search within the given table
383 -- @return Boolean indicating whether the given value occurs within table
384 function contains(table, value)
385 for k, v in pairs(table) do
393 --- Update values in given table with the values from the second given table.
394 -- Both table are - in fact - merged together.
395 -- @param t Table which should be updated
396 -- @param updates Table containing the values to update
397 -- @return Always nil
398 function update(t, updates)
399 for k, v in pairs(updates) do
404 --- Retrieve all keys of given associative table.
405 -- @param t Table to extract keys from
406 -- @return Sorted table containing the keys
410 for k, _ in kspairs(t) do
417 --- Clones the given object and return it's copy.
418 -- @param object Table value to clone
419 -- @param deep Boolean indicating whether to do recursive cloning
420 -- @return Cloned table value
421 function clone(object, deep)
424 for k, v in pairs(object) do
425 if deep and type(v) == "table" then
431 return setmetatable(copy, getmetatable(object))
435 --- Create a dynamic table which automatically creates subtables.
436 -- @return Dynamic Table
438 return setmetatable({}, { __index =
440 return rawget(tbl, key)
441 or rawget(rawset(tbl, key, dtable()), key)
447 -- Serialize the contents of a table value.
448 function _serialize_table(t, seen)
449 assert(not seen[t], "Recursion detected.")
456 for k, v in pairs(t) do
457 if type(k) ~= "number" or k < 1 or math.floor(k) ~= k or ( k - #t ) > 3 then
458 k = serialize_data(k, seen)
459 v = serialize_data(v, seen)
460 data = data .. ( #data > 0 and ", " or "" ) ..
461 '[' .. k .. '] = ' .. v
468 local v = serialize_data(t[i], seen)
469 idata = idata .. ( #idata > 0 and ", " or "" ) .. v
472 return idata .. ( #data > 0 and #idata > 0 and ", " or "" ) .. data
475 --- Recursively serialize given data to lua code, suitable for restoring
476 -- with loadstring().
477 -- @param val Value containing the data to serialize
478 -- @return String value containing the serialized code
481 function serialize_data(val, seen)
482 seen = seen or setmetatable({}, {__mode="k"})
486 elseif type(val) == "number" then
488 elseif type(val) == "string" then
490 elseif type(val) == "boolean" then
491 return val and "true" or "false"
492 elseif type(val) == "function" then
493 return "loadstring(%q)" % get_bytecode(val)
494 elseif type(val) == "table" then
495 return "{ " .. _serialize_table(val, seen) .. " }"
497 return '"[unhandled data type:' .. type(val) .. ']"'
501 --- Restore data previously serialized with serialize_data().
502 -- @param str String containing the data to restore
503 -- @return Value containing the restored data structure
504 -- @see serialize_data
506 function restore_data(str)
507 return loadstring("return " .. str)()
512 -- Byte code manipulation routines
515 --- Return the current runtime bytecode of the given data. The byte code
516 -- will be stripped before it is returned.
517 -- @param val Value to return as bytecode
518 -- @return String value containing the bytecode of the given data
519 function get_bytecode(val)
522 if type(val) == "function" then
523 code = string.dump(val)
525 code = string.dump( loadstring( "return " .. serialize_data(val) ) )
528 return code -- and strip_bytecode(code)
531 --- Strips unnescessary lua bytecode from given string. Information like line
532 -- numbers and debugging numbers will be discarded. Original version by
533 -- Peter Cawley (http://lua-users.org/lists/lua-l/2008-02/msg01158.html)
534 -- @param code String value containing the original lua byte code
535 -- @return String value containing the stripped lua byte code
536 function strip_bytecode(code)
537 local version, format, endian, int, size, ins, num, lnum = code:byte(5, 12)
540 subint = function(code, i, l)
543 val = val * 256 + code:byte(i + n - 1)
548 subint = function(code, i, l)
551 val = val * 256 + code:byte(i + n - 1)
557 local function strip_function(code)
558 local count, offset = subint(code, 1, size)
559 local stripped = { string.rep("\0", size) }
560 local dirty = offset + count
561 offset = offset + count + int * 2 + 4
562 offset = offset + int + subint(code, offset, int) * ins
563 count, offset = subint(code, offset, int)
566 t, offset = subint(code, offset, 1)
570 offset = offset + size + subint(code, offset, size)
572 offset = offset + num
573 elseif t == 254 or t == 9 then
574 offset = offset + lnum
577 count, offset = subint(code, offset, int)
578 stripped[#stripped+1] = code:sub(dirty, offset - 1)
580 local proto, off = strip_function(code:sub(offset, -1))
581 stripped[#stripped+1] = proto
582 offset = offset + off - 1
584 offset = offset + subint(code, offset, int) * int + int
585 count, offset = subint(code, offset, int)
587 offset = offset + subint(code, offset, size) + size + int * 2
589 count, offset = subint(code, offset, int)
591 offset = offset + subint(code, offset, size) + size
593 stripped[#stripped+1] = string.rep("\0", int * 3)
594 return table.concat(stripped), offset
597 return code:sub(1,12) .. strip_function(code:sub(13,-1))
602 -- Sorting iterator functions
605 function _sortiter( t, f )
608 for k, v in pairs(t) do
614 table.sort( keys, f )
618 if _pos <= #keys then
619 return keys[_pos], t[keys[_pos]]
624 --- Return a key, value iterator which returns the values sorted according to
625 -- the provided callback function.
626 -- @param t The table to iterate
627 -- @param f A callback function to decide the order of elements
628 -- @return Function value containing the corresponding iterator
630 return _sortiter( t, f )
633 --- Return a key, value iterator for the given table.
634 -- The table pairs are sorted by key.
635 -- @param t The table to iterate
636 -- @return Function value containing the corresponding iterator
638 return _sortiter( t )
641 --- Return a key, value iterator for the given table.
642 -- The table pairs are sorted by value.
643 -- @param t The table to iterate
644 -- @return Function value containing the corresponding iterator
646 return _sortiter( t, function (a,b) return t[a] < t[b] end )
651 -- System utility functions
654 --- Test whether the current system is operating in big endian mode.
655 -- @return Boolean value indicating whether system is big endian
657 return string.byte(string.dump(function() end), 7) == 0
660 --- Execute given commandline and gather stdout.
661 -- @param command String containing command to execute
662 -- @return String containing the command's stdout
663 function exec(command)
664 local pp = io.popen(command)
665 local data = pp:read("*a")
671 --- Return a line-buffered iterator over the output of given command.
672 -- @param command String containing the command to execute
674 function execi(command)
675 local pp = io.popen(command)
677 return pp and function()
678 local line = pp:read()
689 function execl(command)
690 local pp = io.popen(command)
696 if (line == nil) then break end
704 --- Returns the absolute path to LuCI base directory.
705 -- @return String containing the directory path
707 return require "nixio.fs".dirname(ldebug.__file__)
712 -- Coroutine safe xpcall and pcall versions modified for Luci
714 -- coxpcall 1.13 - Copyright 2005 - Kepler Project (www.keplerproject.org)
716 -- Copyright © 2005 Kepler Project.
717 -- Permission is hereby granted, free of charge, to any person obtaining a
718 -- copy of this software and associated documentation files (the "Software"),
719 -- to deal in the Software without restriction, including without limitation
720 -- the rights to use, copy, modify, merge, publish, distribute, sublicense,
721 -- and/or sell copies of the Software, and to permit persons to whom the
722 -- Software is furnished to do so, subject to the following conditions:
724 -- The above copyright notice and this permission notice shall be
725 -- included in all copies or substantial portions of the Software.
727 -- THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
728 -- EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
729 -- OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
730 -- IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
731 -- DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
732 -- TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE
733 -- OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
735 local performResume, handleReturnValue
736 local oldpcall, oldxpcall = pcall, xpcall
738 setmetatable(coxpt, {__mode = "kv"})
740 -- Identity function for copcall
741 local function copcall_id(trace, ...)
745 --- This is a coroutine-safe drop-in replacement for Lua's "xpcall"-function
746 -- @param f Lua function to be called protected
747 -- @param err Custom error handler
748 -- @param ... Parameters passed to the function
749 -- @return A boolean whether the function call succeeded and the return
750 -- values of either the function or the error handler
751 function coxpcall(f, err, ...)
752 local res, co = oldpcall(coroutine.create, f)
755 local newf = function() return f(unpack(params)) end
756 co = coroutine.create(newf)
758 local c = coroutine.running()
759 coxpt[co] = coxpt[c] or c or 0
761 return performResume(err, co, ...)
764 --- This is a coroutine-safe drop-in replacement for Lua's "pcall"-function
765 -- @param f Lua function to be called protected
766 -- @param ... Parameters passed to the function
767 -- @return A boolean whether the function call succeeded and the returns
768 -- values of the function or the error object
769 function copcall(f, ...)
770 return coxpcall(f, copcall_id, ...)
773 -- Handle return value of protected call
774 function handleReturnValue(err, co, status, ...)
776 return false, err(debug.traceback(co, (...)), ...)
779 if coroutine.status(co) ~= 'suspended' then
783 return performResume(err, co, coroutine.yield(...))
786 -- Resume execution of protected function call
787 function performResume(err, co, ...)
788 return handleReturnValue(err, co, coroutine.resume(co, ...))