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 return a:format(unpack(b))
60 -- Class helper routines
63 -- Instantiates a class
64 local function _instantiate(class, ...)
65 local inst = setmetatable({}, {__index = class})
74 --- Create a Class object (Python-style object model).
75 -- The class object can be instantiated by calling itself.
76 -- Any class functions or shared parameters can be attached to this object.
77 -- Attaching a table to the class object makes this table shared between
78 -- all instances of this class. For object parameters use the __init__ function.
79 -- Classes can inherit member functions and values from a base class.
80 -- Class can be instantiated by calling them. All parameters will be passed
81 -- to the __init__ function of this class - if such a function exists.
82 -- The __init__ function must be used to set any object parameters that are not shared
83 -- with other objects of this class. Any return values will be ignored.
84 -- @param base The base class to inherit from (optional)
85 -- @return A class object
89 return setmetatable({}, {
90 __call = _instantiate,
95 --- Test whether the given object is an instance of the given class.
96 -- @param object Object instance
97 -- @param class Class object to test against
98 -- @return Boolean indicating whether the object is an instance
101 function instanceof(object, class)
102 local meta = getmetatable(object)
103 while meta and meta.__index do
104 if meta.__index == class then
107 meta = getmetatable(meta.__index)
114 -- Scope manipulation routines
117 --- Create a new or get an already existing thread local store associated with
118 -- the current active coroutine. A thread local store is private a table object
119 -- whose values can't be accessed from outside of the running coroutine.
120 -- @return Table value representing the corresponding thread local store
121 function threadlocal()
124 local function get(self, key)
125 local c = coroutine.running()
126 local thread = coxpt[c] or c or 0
127 if not rawget(self, thread) then
130 return rawget(self, thread)[key]
133 local function set(self, key, value)
134 local c = coroutine.running()
135 local thread = coxpt[c] or c or 0
136 if not rawget(self, thread) then
137 rawset(self, thread, {})
139 rawget(self, thread)[key] = value
142 setmetatable(tbl, {__index = get, __newindex = set, __mode = "k"})
149 -- Debugging routines
152 --- Write given object to stderr.
153 -- @param obj Value to write to stderr
154 -- @return Boolean indicating whether the write operation was successful
156 return io.stderr:write(tostring(obj) .. "\n")
159 --- Recursively dumps a table to stdout, useful for testing and debugging.
160 -- @param t Table value to dump
161 -- @param maxdepth Maximum depth
162 -- @return Always nil
163 function dumptable(t, maxdepth, i, seen)
165 seen = seen or setmetatable({}, {__mode="k"})
167 for k,v in pairs(t) do
168 perror(string.rep("\t", i) .. tostring(k) .. "\t" .. tostring(v))
169 if type(v) == "table" and (not maxdepth or i < maxdepth) then
172 dumptable(v, maxdepth, i+1, seen)
174 perror(string.rep("\t", i) .. "*** RECURSION ***")
182 -- String and data manipulation routines
185 --- Escapes all occurrences of the given character in given string.
186 -- @param s String value containing unescaped characters
187 -- @param c String value with character to escape (optional, defaults to "\")
188 -- @return String value with each occurrence of character escaped with "\"
189 function escape(s, c)
191 return s:gsub(c, "\\" .. c)
194 --- Create valid XML PCDATA from given string.
195 -- @param value String value containing the data to escape
196 -- @return String value containing the escaped data
197 local function _pcdata_repl(c)
198 local i = string.byte(c)
200 if ( i >= 0x00 and i <= 0x08 ) or ( i >= 0x0B and i <= 0x0C ) or
201 ( i >= 0x0E and i <= 0x1F ) or ( i == 0x7F )
205 elseif ( i == 0x26 ) or ( i == 0x27 ) or ( i == 0x22 ) or
206 ( i == 0x3C ) or ( i == 0x3E )
208 return string.format("&#%i;", i)
214 function pcdata(value)
215 return value and tostring(value):gsub("[&\"'<>%c]", _pcdata_repl)
218 --- Strip HTML tags from given string.
219 -- @param value String containing the HTML text
220 -- @return String with HTML tags stripped of
221 function striptags(s)
222 return pcdata(s:gsub("</?[A-Za-z][A-Za-z0-9:_%-]*[^>]*>", " "):gsub("%s+", " "))
225 --- Splits given string on a defined separator sequence and return a table
226 -- containing the resulting substrings. The optional max parameter specifies
227 -- the number of bytes to process, regardless of the actual length of the given
228 -- string. The optional last parameter, regex, specifies whether the separator
229 -- sequence is interpreted as regular expression.
230 -- @param str String value containing the data to split up
231 -- @param pat String with separator pattern (optional, defaults to "\n")
232 -- @param max Maximum times to split (optional)
233 -- @param regex Boolean indicating whether to interpret the separator
234 -- pattern as regular expression (optional, default is false)
235 -- @return Table containing the resulting substrings
236 function split(str, pat, max, regex)
256 local s, e = str:find(pat, c, not regex)
258 if s and max < 0 then
261 t[#t+1] = str:sub(c, s and s - 1)
263 c = e and e + 1 or #str + 1
264 until not s or max < 0
269 --- Remove leading and trailing whitespace from given string value.
270 -- @param str String value containing whitespace padded data
271 -- @return String value with leading and trailing space removed
273 return (str:gsub("^%s*(.-)%s*$", "%1"))
276 --- Count the occurences of given substring in given string.
277 -- @param str String to search in
278 -- @param pattern String containing pattern to find
279 -- @return Number of found occurences
280 function cmatch(str, pat)
282 for _ in str:gmatch(pat) do count = count + 1 end
286 --- Parse certain units from the given string and return the canonical integer
287 -- value or 0 if the unit is unknown. Upper- or lower case is irrelevant.
288 -- Recognized units are:
289 -- o "y" - one year (60*60*24*366)
290 -- o "m" - one month (60*60*24*31)
291 -- o "w" - one week (60*60*24*7)
292 -- o "d" - one day (60*60*24)
293 -- o "h" - one hour (60*60)
294 -- o "min" - one minute (60)
295 -- o "kb" - one kilobyte (1024)
296 -- o "mb" - one megabyte (1024*1024)
297 -- o "gb" - one gigabyte (1024*1024*1024)
298 -- o "kib" - one si kilobyte (1000)
299 -- o "mib" - one si megabyte (1000*1000)
300 -- o "gib" - one si gigabyte (1000*1000*1000)
301 -- @param ustr String containing a numerical value with trailing unit
302 -- @return Number containing the canonical value
303 function parse_units(ustr)
310 y = 60 * 60 * 24 * 366,
311 m = 60 * 60 * 24 * 31,
312 w = 60 * 60 * 24 * 7,
320 gb = 1024 * 1024 * 1024,
322 -- storage sizes (si)
325 gib = 1000 * 1000 * 1000
328 -- parse input string
329 for spec in ustr:lower():gmatch("[0-9%.]+[a-zA-Z]*") do
331 local num = spec:gsub("[^0-9%.]+$","")
332 local spn = spec:gsub("^[0-9%.]+", "")
334 if map[spn] or map[spn:sub(1,1)] then
335 val = val + num * ( map[spn] or map[spn:sub(1,1)] )
345 -- also register functions above in the central string class for convenience
346 string.escape = escape
347 string.pcdata = pcdata
348 string.striptags = striptags
351 string.cmatch = cmatch
352 string.parse_units = parse_units
355 --- Appends numerically indexed tables or single objects to a given table.
356 -- @param src Target table
357 -- @param ... Objects to insert
358 -- @return Target table
359 function append(src, ...)
360 for i, a in ipairs({...}) do
361 if type(a) == "table" then
362 for j, v in ipairs(a) do
372 --- Combines two or more numerically indexed tables and single objects into one table.
373 -- @param tbl1 Table value to combine
374 -- @param tbl2 Table value to combine
375 -- @param ... More tables to combine
376 -- @return Table value containing all values of given tables
377 function combine(...)
378 return append({}, ...)
381 --- Checks whether the given table contains the given value.
382 -- @param table Table value
383 -- @param value Value to search within the given table
384 -- @return Boolean indicating whether the given value occurs within table
385 function contains(table, value)
386 for k, v in pairs(table) do
394 --- Update values in given table with the values from the second given table.
395 -- Both table are - in fact - merged together.
396 -- @param t Table which should be updated
397 -- @param updates Table containing the values to update
398 -- @return Always nil
399 function update(t, updates)
400 for k, v in pairs(updates) do
405 --- Retrieve all keys of given associative table.
406 -- @param t Table to extract keys from
407 -- @return Sorted table containing the keys
411 for k, _ in kspairs(t) do
418 --- Clones the given object and return it's copy.
419 -- @param object Table value to clone
420 -- @param deep Boolean indicating whether to do recursive cloning
421 -- @return Cloned table value
422 function clone(object, deep)
425 for k, v in pairs(object) do
426 if deep and type(v) == "table" then
432 return setmetatable(copy, getmetatable(object))
436 --- Create a dynamic table which automatically creates subtables.
437 -- @return Dynamic Table
439 return setmetatable({}, { __index =
441 return rawget(tbl, key)
442 or rawget(rawset(tbl, key, dtable()), key)
448 -- Serialize the contents of a table value.
449 function _serialize_table(t, seen)
450 assert(not seen[t], "Recursion detected.")
457 for k, v in pairs(t) do
458 if type(k) ~= "number" or k < 1 or math.floor(k) ~= k or ( k - #t ) > 3 then
459 k = serialize_data(k, seen)
460 v = serialize_data(v, seen)
461 data = data .. ( #data > 0 and ", " or "" ) ..
462 '[' .. k .. '] = ' .. v
469 local v = serialize_data(t[i], seen)
470 idata = idata .. ( #idata > 0 and ", " or "" ) .. v
473 return idata .. ( #data > 0 and #idata > 0 and ", " or "" ) .. data
476 --- Recursively serialize given data to lua code, suitable for restoring
477 -- with loadstring().
478 -- @param val Value containing the data to serialize
479 -- @return String value containing the serialized code
482 function serialize_data(val, seen)
483 seen = seen or setmetatable({}, {__mode="k"})
487 elseif type(val) == "number" then
489 elseif type(val) == "string" then
491 elseif type(val) == "boolean" then
492 return val and "true" or "false"
493 elseif type(val) == "function" then
494 return "loadstring(%q)" % get_bytecode(val)
495 elseif type(val) == "table" then
496 return "{ " .. _serialize_table(val, seen) .. " }"
498 return '"[unhandled data type:' .. type(val) .. ']"'
502 --- Restore data previously serialized with serialize_data().
503 -- @param str String containing the data to restore
504 -- @return Value containing the restored data structure
505 -- @see serialize_data
507 function restore_data(str)
508 return loadstring("return " .. str)()
513 -- Byte code manipulation routines
516 --- Return the current runtime bytecode of the given data. The byte code
517 -- will be stripped before it is returned.
518 -- @param val Value to return as bytecode
519 -- @return String value containing the bytecode of the given data
520 function get_bytecode(val)
523 if type(val) == "function" then
524 code = string.dump(val)
526 code = string.dump( loadstring( "return " .. serialize_data(val) ) )
529 return code and strip_bytecode(code)
532 --- Strips unnescessary lua bytecode from given string. Information like line
533 -- numbers and debugging numbers will be discarded. Original version by
534 -- Peter Cawley (http://lua-users.org/lists/lua-l/2008-02/msg01158.html)
535 -- @param code String value containing the original lua byte code
536 -- @return String value containing the stripped lua byte code
537 function strip_bytecode(code)
538 local version, format, endian, int, size, ins, num, lnum = code:byte(5, 12)
541 subint = function(code, i, l)
544 val = val * 256 + code:byte(i + n - 1)
549 subint = function(code, i, l)
552 val = val * 256 + code:byte(i + n - 1)
558 local function strip_function(code)
559 local count, offset = subint(code, 1, size)
560 local stripped = { string.rep("\0", size) }
561 local dirty = offset + count
562 offset = offset + count + int * 2 + 4
563 offset = offset + int + subint(code, offset, int) * ins
564 count, offset = subint(code, offset, int)
567 t, offset = subint(code, offset, 1)
571 offset = offset + size + subint(code, offset, size)
573 offset = offset + num
574 elseif t == 254 or t == 9 then
575 offset = offset + lnum
578 count, offset = subint(code, offset, int)
579 stripped[#stripped+1] = code:sub(dirty, offset - 1)
581 local proto, off = strip_function(code:sub(offset, -1))
582 stripped[#stripped+1] = proto
583 offset = offset + off - 1
585 offset = offset + subint(code, offset, int) * int + int
586 count, offset = subint(code, offset, int)
588 offset = offset + subint(code, offset, size) + size + int * 2
590 count, offset = subint(code, offset, int)
592 offset = offset + subint(code, offset, size) + size
594 stripped[#stripped+1] = string.rep("\0", int * 3)
595 return table.concat(stripped), offset
598 return code:sub(1,12) .. strip_function(code:sub(13,-1))
603 -- Sorting iterator functions
606 function _sortiter( t, f )
609 for k, v in pairs(t) do
615 table.sort( keys, f )
619 if _pos <= #keys then
620 return keys[_pos], t[keys[_pos]]
625 --- Return a key, value iterator which returns the values sorted according to
626 -- the provided callback function.
627 -- @param t The table to iterate
628 -- @param f A callback function to decide the order of elements
629 -- @return Function value containing the corresponding iterator
631 return _sortiter( t, f )
634 --- Return a key, value iterator for the given table.
635 -- The table pairs are sorted by key.
636 -- @param t The table to iterate
637 -- @return Function value containing the corresponding iterator
639 return _sortiter( t )
642 --- Return a key, value iterator for the given table.
643 -- The table pairs are sorted by value.
644 -- @param t The table to iterate
645 -- @return Function value containing the corresponding iterator
647 return _sortiter( t, function (a,b) return t[a] < t[b] end )
652 -- System utility functions
655 --- Test whether the current system is operating in big endian mode.
656 -- @return Boolean value indicating whether system is big endian
658 return string.byte(string.dump(function() end), 7) == 0
661 --- Execute given commandline and gather stdout.
662 -- @param command String containing command to execute
663 -- @return String containing the command's stdout
664 function exec(command)
665 local pp = io.popen(command)
666 local data = pp:read("*a")
672 --- Return a line-buffered iterator over the output of given command.
673 -- @param command String containing the command to execute
675 function execi(command)
676 local pp = io.popen(command)
678 return pp and function()
679 local line = pp:read()
690 function execl(command)
691 local pp = io.popen(command)
697 if (line == nil) then break end
705 --- Returns the absolute path to LuCI base directory.
706 -- @return String containing the directory path
708 return require "luci.fs".dirname(ldebug.__file__)
713 -- Coroutine safe xpcall and pcall versions modified for Luci
715 -- coxpcall 1.13 - Copyright 2005 - Kepler Project (www.keplerproject.org)
717 -- Copyright © 2005 Kepler Project.
718 -- Permission is hereby granted, free of charge, to any person obtaining a
719 -- copy of this software and associated documentation files (the "Software"),
720 -- to deal in the Software without restriction, including without limitation
721 -- the rights to use, copy, modify, merge, publish, distribute, sublicense,
722 -- and/or sell copies of the Software, and to permit persons to whom the
723 -- Software is furnished to do so, subject to the following conditions:
725 -- The above copyright notice and this permission notice shall be
726 -- included in all copies or substantial portions of the Software.
728 -- THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
729 -- EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
730 -- OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
731 -- IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
732 -- DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
733 -- TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE
734 -- OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
736 local performResume, handleReturnValue
737 local oldpcall, oldxpcall = pcall, xpcall
739 setmetatable(coxpt, {__mode = "kv"})
741 -- Identity function for copcall
742 local function copcall_id(trace, ...)
746 --- This is a coroutine-safe drop-in replacement for Lua's "xpcall"-function
747 -- @param f Lua function to be called protected
748 -- @param err Custom error handler
749 -- @param ... Parameters passed to the function
750 -- @return A boolean whether the function call succeeded and the return
751 -- values of either the function or the error handler
752 function coxpcall(f, err, ...)
753 local res, co = oldpcall(coroutine.create, f)
756 local newf = function() return f(unpack(params)) end
757 co = coroutine.create(newf)
759 local c = coroutine.running()
760 coxpt[co] = coxpt[c] or c or 0
762 return performResume(err, co, ...)
765 --- This is a coroutine-safe drop-in replacement for Lua's "pcall"-function
766 -- @param f Lua function to be called protected
767 -- @param ... Parameters passed to the function
768 -- @return A boolean whether the function call succeeded and the returns
769 -- values of the function or the error object
770 function copcall(f, ...)
771 return coxpcall(f, copcall_id, ...)
774 -- Handle return value of protected call
775 function handleReturnValue(err, co, status, ...)
777 return false, err(debug.traceback(co, (...)), ...)
779 if coroutine.status(co) == 'suspended' then
780 return performResume(err, co, coroutine.yield(...))
786 -- Resume execution of protected function call
787 function performResume(err, co, ...)
788 if get_memory_limit and get_memory_limit() > 0 and
789 collectgarbage("count") > (get_memory_limit() * 0.8)
791 collectgarbage("collect")
794 return handleReturnValue(err, co, coroutine.resume(co, ...))