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 tparser = require "luci.template.parser"
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
41 local collectgarbage, get_memory_limit = collectgarbage, get_memory_limit
43 --- LuCI utility functions.
47 -- Pythonic string formatting extension
49 getmetatable("").__mod = function(a, b)
52 elseif type(b) == "table" then
53 for k, _ in pairs(b) do if type(b[k]) == "userdata" then b[k] = tostring(b[k]) end end
54 return a:format(unpack(b))
56 if type(b) == "userdata" then b = tostring(b) end
63 -- Class helper routines
66 -- Instantiates a class
67 local function _instantiate(class, ...)
68 local inst = setmetatable({}, {__index = class})
77 --- Create a Class object (Python-style object model).
78 -- The class object can be instantiated by calling itself.
79 -- Any class functions or shared parameters can be attached to this object.
80 -- Attaching a table to the class object makes this table shared between
81 -- all instances of this class. For object parameters use the __init__ function.
82 -- Classes can inherit member functions and values from a base class.
83 -- Class can be instantiated by calling them. All parameters will be passed
84 -- to the __init__ function of this class - if such a function exists.
85 -- The __init__ function must be used to set any object parameters that are not shared
86 -- with other objects of this class. Any return values will be ignored.
87 -- @param base The base class to inherit from (optional)
88 -- @return A class object
92 return setmetatable({}, {
93 __call = _instantiate,
98 --- Test whether the given object is an instance of the given class.
99 -- @param object Object instance
100 -- @param class Class object to test against
101 -- @return Boolean indicating whether the object is an instance
104 function instanceof(object, class)
105 local meta = getmetatable(object)
106 while meta and meta.__index do
107 if meta.__index == class then
110 meta = getmetatable(meta.__index)
117 -- Scope manipulation routines
123 __index = function(self, key)
124 local t = rawget(self, coxpt[coroutine.running()]
125 or coroutine.running() or 0)
129 __newindex = function(self, key, value)
130 local c = coxpt[coroutine.running()] or coroutine.running() or 0
131 if not rawget(self, c) then
132 rawset(self, c, { [key] = value })
134 rawget(self, c)[key] = value
139 --- Create a new or get an already existing thread local store associated with
140 -- the current active coroutine. A thread local store is private a table object
141 -- whose values can't be accessed from outside of the running coroutine.
142 -- @return Table value representing the corresponding thread local store
143 function threadlocal(tbl)
144 return setmetatable(tbl or {}, tl_meta)
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 function pcdata(value)
198 return value and tparser.sanitize_pcdata(tostring(value))
201 --- Strip HTML tags from given string.
202 -- @param value String containing the HTML text
203 -- @return String with HTML tags stripped of
204 function striptags(s)
205 return pcdata(tostring(s):gsub("</?[A-Za-z][A-Za-z0-9:_%-]*[^>]*>", " "):gsub("%s+", " "))
208 --- Splits given string on a defined separator sequence and return a table
209 -- containing the resulting substrings. The optional max parameter specifies
210 -- the number of bytes to process, regardless of the actual length of the given
211 -- string. The optional last parameter, regex, specifies whether the separator
212 -- sequence is interpreted as regular expression.
213 -- @param str String value containing the data to split up
214 -- @param pat String with separator pattern (optional, defaults to "\n")
215 -- @param max Maximum times to split (optional)
216 -- @param regex Boolean indicating whether to interpret the separator
217 -- pattern as regular expression (optional, default is false)
218 -- @return Table containing the resulting substrings
219 function split(str, pat, max, regex)
239 local s, e = str:find(pat, c, not regex)
241 if s and max < 0 then
244 t[#t+1] = str:sub(c, s and s - 1)
246 c = e and e + 1 or #str + 1
247 until not s or max < 0
252 --- Remove leading and trailing whitespace from given string value.
253 -- @param str String value containing whitespace padded data
254 -- @return String value with leading and trailing space removed
256 return (str:gsub("^%s*(.-)%s*$", "%1"))
259 --- Count the occurences of given substring in given string.
260 -- @param str String to search in
261 -- @param pattern String containing pattern to find
262 -- @return Number of found occurences
263 function cmatch(str, pat)
265 for _ in str:gmatch(pat) do count = count + 1 end
269 --- Return a matching iterator for the given value. The iterator will return
270 -- one token per invocation, the tokens are separated by whitespace. If the
271 -- input value is a table, it is transformed into a string first. A nil value
272 -- will result in a valid interator which aborts with the first invocation.
273 -- @param val The value to scan (table, string or nil)
274 -- @return Iterator which returns one token per call
278 elseif type(v) == "table" then
279 v = table.concat(v, " ")
280 elseif type(v) ~= "string" then
284 return v:gmatch("%S+")
287 --- Parse certain units from the given string and return the canonical integer
288 -- value or 0 if the unit is unknown. Upper- or lower case is irrelevant.
289 -- Recognized units are:
290 -- o "y" - one year (60*60*24*366)
291 -- o "m" - one month (60*60*24*31)
292 -- o "w" - one week (60*60*24*7)
293 -- o "d" - one day (60*60*24)
294 -- o "h" - one hour (60*60)
295 -- o "min" - one minute (60)
296 -- o "kb" - one kilobyte (1024)
297 -- o "mb" - one megabyte (1024*1024)
298 -- o "gb" - one gigabyte (1024*1024*1024)
299 -- o "kib" - one si kilobyte (1000)
300 -- o "mib" - one si megabyte (1000*1000)
301 -- o "gib" - one si gigabyte (1000*1000*1000)
302 -- @param ustr String containing a numerical value with trailing unit
303 -- @return Number containing the canonical value
304 function parse_units(ustr)
311 y = 60 * 60 * 24 * 366,
312 m = 60 * 60 * 24 * 31,
313 w = 60 * 60 * 24 * 7,
321 gb = 1024 * 1024 * 1024,
323 -- storage sizes (si)
326 gib = 1000 * 1000 * 1000
329 -- parse input string
330 for spec in ustr:lower():gmatch("[0-9%.]+[a-zA-Z]*") do
332 local num = spec:gsub("[^0-9%.]+$","")
333 local spn = spec:gsub("^[0-9%.]+", "")
335 if map[spn] or map[spn:sub(1,1)] then
336 val = val + num * ( map[spn] or map[spn:sub(1,1)] )
346 -- also register functions above in the central string class for convenience
347 string.escape = escape
348 string.pcdata = pcdata
349 string.striptags = striptags
352 string.cmatch = cmatch
353 string.parse_units = parse_units
356 --- Appends numerically indexed tables or single objects to a given table.
357 -- @param src Target table
358 -- @param ... Objects to insert
359 -- @return Target table
360 function append(src, ...)
361 for i, a in ipairs({...}) do
362 if type(a) == "table" then
363 for j, v in ipairs(a) do
373 --- Combines two or more numerically indexed tables and single objects into one table.
374 -- @param tbl1 Table value to combine
375 -- @param tbl2 Table value to combine
376 -- @param ... More tables to combine
377 -- @return Table value containing all values of given tables
378 function combine(...)
379 return append({}, ...)
382 --- Checks whether the given table contains the given value.
383 -- @param table Table value
384 -- @param value Value to search within the given table
385 -- @return Boolean indicating whether the given value occurs within table
386 function contains(table, value)
387 for k, v in pairs(table) do
395 --- Update values in given table with the values from the second given table.
396 -- Both table are - in fact - merged together.
397 -- @param t Table which should be updated
398 -- @param updates Table containing the values to update
399 -- @return Always nil
400 function update(t, updates)
401 for k, v in pairs(updates) do
406 --- Retrieve all keys of given associative table.
407 -- @param t Table to extract keys from
408 -- @return Sorted table containing the keys
412 for k, _ in kspairs(t) do
419 --- Clones the given object and return it's copy.
420 -- @param object Table value to clone
421 -- @param deep Boolean indicating whether to do recursive cloning
422 -- @return Cloned table value
423 function clone(object, deep)
426 for k, v in pairs(object) do
427 if deep and type(v) == "table" then
433 return setmetatable(copy, getmetatable(object))
437 --- Create a dynamic table which automatically creates subtables.
438 -- @return Dynamic Table
440 return setmetatable({}, { __index =
442 return rawget(tbl, key)
443 or rawget(rawset(tbl, key, dtable()), key)
449 -- Serialize the contents of a table value.
450 function _serialize_table(t, seen)
451 assert(not seen[t], "Recursion detected.")
458 for k, v in pairs(t) do
459 if type(k) ~= "number" or k < 1 or math.floor(k) ~= k or ( k - #t ) > 3 then
460 k = serialize_data(k, seen)
461 v = serialize_data(v, seen)
462 data = data .. ( #data > 0 and ", " or "" ) ..
463 '[' .. k .. '] = ' .. v
470 local v = serialize_data(t[i], seen)
471 idata = idata .. ( #idata > 0 and ", " or "" ) .. v
474 return idata .. ( #data > 0 and #idata > 0 and ", " or "" ) .. data
477 --- Recursively serialize given data to lua code, suitable for restoring
478 -- with loadstring().
479 -- @param val Value containing the data to serialize
480 -- @return String value containing the serialized code
483 function serialize_data(val, seen)
484 seen = seen or setmetatable({}, {__mode="k"})
488 elseif type(val) == "number" then
490 elseif type(val) == "string" then
492 elseif type(val) == "boolean" then
493 return val and "true" or "false"
494 elseif type(val) == "function" then
495 return "loadstring(%q)" % get_bytecode(val)
496 elseif type(val) == "table" then
497 return "{ " .. _serialize_table(val, seen) .. " }"
499 return '"[unhandled data type:' .. type(val) .. ']"'
503 --- Restore data previously serialized with serialize_data().
504 -- @param str String containing the data to restore
505 -- @return Value containing the restored data structure
506 -- @see serialize_data
508 function restore_data(str)
509 return loadstring("return " .. str)()
514 -- Byte code manipulation routines
517 --- Return the current runtime bytecode of the given data. The byte code
518 -- will be stripped before it is returned.
519 -- @param val Value to return as bytecode
520 -- @return String value containing the bytecode of the given data
521 function get_bytecode(val)
524 if type(val) == "function" then
525 code = string.dump(val)
527 code = string.dump( loadstring( "return " .. serialize_data(val) ) )
530 return code -- and strip_bytecode(code)
533 --- Strips unnescessary lua bytecode from given string. Information like line
534 -- numbers and debugging numbers will be discarded. Original version by
535 -- Peter Cawley (http://lua-users.org/lists/lua-l/2008-02/msg01158.html)
536 -- @param code String value containing the original lua byte code
537 -- @return String value containing the stripped lua byte code
538 function strip_bytecode(code)
539 local version, format, endian, int, size, ins, num, lnum = code:byte(5, 12)
542 subint = function(code, i, l)
545 val = val * 256 + code:byte(i + n - 1)
550 subint = function(code, i, l)
553 val = val * 256 + code:byte(i + n - 1)
559 local function strip_function(code)
560 local count, offset = subint(code, 1, size)
561 local stripped = { string.rep("\0", size) }
562 local dirty = offset + count
563 offset = offset + count + int * 2 + 4
564 offset = offset + int + subint(code, offset, int) * ins
565 count, offset = subint(code, offset, int)
568 t, offset = subint(code, offset, 1)
572 offset = offset + size + subint(code, offset, size)
574 offset = offset + num
575 elseif t == 254 or t == 9 then
576 offset = offset + lnum
579 count, offset = subint(code, offset, int)
580 stripped[#stripped+1] = code:sub(dirty, offset - 1)
582 local proto, off = strip_function(code:sub(offset, -1))
583 stripped[#stripped+1] = proto
584 offset = 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+1] = string.rep("\0", int * 3)
596 return table.concat(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 "nixio.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, (...)), ...)
781 if coroutine.status(co) ~= 'suspended' then
785 return performResume(err, co, coroutine.yield(...))
788 -- Resume execution of protected function call
789 function performResume(err, co, ...)
790 return handleReturnValue(err, co, coroutine.resume(co, ...))