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, next, loadstring = ipairs, pairs, next, 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 --- Create valid XML PCDATA from given string.
186 -- @param value String value containing the data to escape
187 -- @return String value containing the escaped data
188 function pcdata(value)
189 return value and tparser.pcdata(tostring(value))
192 --- Strip HTML tags from given string.
193 -- @param value String containing the HTML text
194 -- @return String with HTML tags stripped of
195 function striptags(value)
196 return value and tparser.striptags(tostring(value))
199 --- Splits given string on a defined separator sequence and return a table
200 -- containing the resulting substrings. The optional max parameter specifies
201 -- the number of bytes to process, regardless of the actual length of the given
202 -- string. The optional last parameter, regex, specifies whether the separator
203 -- sequence is interpreted as regular expression.
204 -- @param str String value containing the data to split up
205 -- @param pat String with separator pattern (optional, defaults to "\n")
206 -- @param max Maximum times to split (optional)
207 -- @param regex Boolean indicating whether to interpret the separator
208 -- pattern as regular expression (optional, default is false)
209 -- @return Table containing the resulting substrings
210 function split(str, pat, max, regex)
230 local s, e = str:find(pat, c, not regex)
232 if s and max < 0 then
235 t[#t+1] = str:sub(c, s and s - 1)
237 c = e and e + 1 or #str + 1
238 until not s or max < 0
243 --- Remove leading and trailing whitespace from given string value.
244 -- @param str String value containing whitespace padded data
245 -- @return String value with leading and trailing space removed
247 return (str:gsub("^%s*(.-)%s*$", "%1"))
250 --- Count the occurences of given substring in given string.
251 -- @param str String to search in
252 -- @param pattern String containing pattern to find
253 -- @return Number of found occurences
254 function cmatch(str, pat)
256 for _ in str:gmatch(pat) do count = count + 1 end
260 --- Return a matching iterator for the given value. The iterator will return
261 -- one token per invocation, the tokens are separated by whitespace. If the
262 -- input value is a table, it is transformed into a string first. A nil value
263 -- will result in a valid interator which aborts with the first invocation.
264 -- @param val The value to scan (table, string or nil)
265 -- @return Iterator which returns one token per call
267 if type(v) == "table" then
274 elseif type(v) == "number" or type(v) == "boolean" then
283 elseif type(v) == "userdata" or type(v) == "string" then
284 return tostring(v):gmatch("%S+")
287 return function() end
290 --- Parse certain units from the given string and return the canonical integer
291 -- value or 0 if the unit is unknown. Upper- or lower case is irrelevant.
292 -- Recognized units are:
293 -- o "y" - one year (60*60*24*366)
294 -- o "m" - one month (60*60*24*31)
295 -- o "w" - one week (60*60*24*7)
296 -- o "d" - one day (60*60*24)
297 -- o "h" - one hour (60*60)
298 -- o "min" - one minute (60)
299 -- o "kb" - one kilobyte (1024)
300 -- o "mb" - one megabyte (1024*1024)
301 -- o "gb" - one gigabyte (1024*1024*1024)
302 -- o "kib" - one si kilobyte (1000)
303 -- o "mib" - one si megabyte (1000*1000)
304 -- o "gib" - one si gigabyte (1000*1000*1000)
305 -- @param ustr String containing a numerical value with trailing unit
306 -- @return Number containing the canonical value
307 function parse_units(ustr)
314 y = 60 * 60 * 24 * 366,
315 m = 60 * 60 * 24 * 31,
316 w = 60 * 60 * 24 * 7,
324 gb = 1024 * 1024 * 1024,
326 -- storage sizes (si)
329 gib = 1000 * 1000 * 1000
332 -- parse input string
333 for spec in ustr:lower():gmatch("[0-9%.]+[a-zA-Z]*") do
335 local num = spec:gsub("[^0-9%.]+$","")
336 local spn = spec:gsub("^[0-9%.]+", "")
338 if map[spn] or map[spn:sub(1,1)] then
339 val = val + num * ( map[spn] or map[spn:sub(1,1)] )
349 -- also register functions above in the central string class for convenience
350 string.pcdata = pcdata
351 string.striptags = striptags
354 string.cmatch = cmatch
355 string.parse_units = parse_units
358 --- Appends numerically indexed tables or single objects to a given table.
359 -- @param src Target table
360 -- @param ... Objects to insert
361 -- @return Target table
362 function append(src, ...)
363 for i, a in ipairs({...}) do
364 if type(a) == "table" then
365 for j, v in ipairs(a) do
375 --- Combines two or more numerically indexed tables and single objects into one table.
376 -- @param tbl1 Table value to combine
377 -- @param tbl2 Table value to combine
378 -- @param ... More tables to combine
379 -- @return Table value containing all values of given tables
380 function combine(...)
381 return append({}, ...)
384 --- Checks whether the given table contains the given value.
385 -- @param table Table value
386 -- @param value Value to search within the given table
387 -- @return Boolean indicating whether the given value occurs within table
388 function contains(table, value)
389 for k, v in pairs(table) do
397 --- Update values in given table with the values from the second given table.
398 -- Both table are - in fact - merged together.
399 -- @param t Table which should be updated
400 -- @param updates Table containing the values to update
401 -- @return Always nil
402 function update(t, updates)
403 for k, v in pairs(updates) do
408 --- Retrieve all keys of given associative table.
409 -- @param t Table to extract keys from
410 -- @return Sorted table containing the keys
414 for k, _ in kspairs(t) do
421 --- Clones the given object and return it's copy.
422 -- @param object Table value to clone
423 -- @param deep Boolean indicating whether to do recursive cloning
424 -- @return Cloned table value
425 function clone(object, deep)
428 for k, v in pairs(object) do
429 if deep and type(v) == "table" then
435 return setmetatable(copy, getmetatable(object))
439 --- Create a dynamic table which automatically creates subtables.
440 -- @return Dynamic Table
442 return setmetatable({}, { __index =
444 return rawget(tbl, key)
445 or rawget(rawset(tbl, key, dtable()), key)
451 -- Serialize the contents of a table value.
452 function _serialize_table(t, seen)
453 assert(not seen[t], "Recursion detected.")
460 for k, v in pairs(t) do
461 if type(k) ~= "number" or k < 1 or math.floor(k) ~= k or ( k - #t ) > 3 then
462 k = serialize_data(k, seen)
463 v = serialize_data(v, seen)
464 data = data .. ( #data > 0 and ", " or "" ) ..
465 '[' .. k .. '] = ' .. v
472 local v = serialize_data(t[i], seen)
473 idata = idata .. ( #idata > 0 and ", " or "" ) .. v
476 return idata .. ( #data > 0 and #idata > 0 and ", " or "" ) .. data
479 --- Recursively serialize given data to lua code, suitable for restoring
480 -- with loadstring().
481 -- @param val Value containing the data to serialize
482 -- @return String value containing the serialized code
485 function serialize_data(val, seen)
486 seen = seen or setmetatable({}, {__mode="k"})
490 elseif type(val) == "number" then
492 elseif type(val) == "string" then
494 elseif type(val) == "boolean" then
495 return val and "true" or "false"
496 elseif type(val) == "function" then
497 return "loadstring(%q)" % get_bytecode(val)
498 elseif type(val) == "table" then
499 return "{ " .. _serialize_table(val, seen) .. " }"
501 return '"[unhandled data type:' .. type(val) .. ']"'
505 --- Restore data previously serialized with serialize_data().
506 -- @param str String containing the data to restore
507 -- @return Value containing the restored data structure
508 -- @see serialize_data
510 function restore_data(str)
511 return loadstring("return " .. str)()
516 -- Byte code manipulation routines
519 --- Return the current runtime bytecode of the given data. The byte code
520 -- will be stripped before it is returned.
521 -- @param val Value to return as bytecode
522 -- @return String value containing the bytecode of the given data
523 function get_bytecode(val)
526 if type(val) == "function" then
527 code = string.dump(val)
529 code = string.dump( loadstring( "return " .. serialize_data(val) ) )
532 return code -- and strip_bytecode(code)
535 --- Strips unnescessary lua bytecode from given string. Information like line
536 -- numbers and debugging numbers will be discarded. Original version by
537 -- Peter Cawley (http://lua-users.org/lists/lua-l/2008-02/msg01158.html)
538 -- @param code String value containing the original lua byte code
539 -- @return String value containing the stripped lua byte code
540 function strip_bytecode(code)
541 local version, format, endian, int, size, ins, num, lnum = code:byte(5, 12)
544 subint = function(code, i, l)
547 val = val * 256 + code:byte(i + n - 1)
552 subint = function(code, i, l)
555 val = val * 256 + code:byte(i + n - 1)
561 local function strip_function(code)
562 local count, offset = subint(code, 1, size)
563 local stripped = { string.rep("\0", size) }
564 local dirty = offset + count
565 offset = offset + count + int * 2 + 4
566 offset = offset + int + subint(code, offset, int) * ins
567 count, offset = subint(code, offset, int)
570 t, offset = subint(code, offset, 1)
574 offset = offset + size + subint(code, offset, size)
576 offset = offset + num
577 elseif t == 254 or t == 9 then
578 offset = offset + lnum
581 count, offset = subint(code, offset, int)
582 stripped[#stripped+1] = code:sub(dirty, offset - 1)
584 local proto, off = strip_function(code:sub(offset, -1))
585 stripped[#stripped+1] = proto
586 offset = offset + off - 1
588 offset = offset + subint(code, offset, int) * int + int
589 count, offset = subint(code, offset, int)
591 offset = offset + subint(code, offset, size) + size + int * 2
593 count, offset = subint(code, offset, int)
595 offset = offset + subint(code, offset, size) + size
597 stripped[#stripped+1] = string.rep("\0", int * 3)
598 return table.concat(stripped), offset
601 return code:sub(1,12) .. strip_function(code:sub(13,-1))
606 -- Sorting iterator functions
609 function _sortiter( t, f )
612 for k, v in pairs(t) do
618 table.sort( keys, f )
622 if _pos <= #keys then
623 return keys[_pos], t[keys[_pos]]
628 --- Return a key, value iterator which returns the values sorted according to
629 -- the provided callback function.
630 -- @param t The table to iterate
631 -- @param f A callback function to decide the order of elements
632 -- @return Function value containing the corresponding iterator
634 return _sortiter( t, f )
637 --- Return a key, value iterator for the given table.
638 -- The table pairs are sorted by key.
639 -- @param t The table to iterate
640 -- @return Function value containing the corresponding iterator
642 return _sortiter( t )
645 --- Return a key, value iterator for the given table.
646 -- The table pairs are sorted by value.
647 -- @param t The table to iterate
648 -- @return Function value containing the corresponding iterator
650 return _sortiter( t, function (a,b) return t[a] < t[b] end )
655 -- System utility functions
658 --- Test whether the current system is operating in big endian mode.
659 -- @return Boolean value indicating whether system is big endian
661 return string.byte(string.dump(function() end), 7) == 0
664 --- Execute given commandline and gather stdout.
665 -- @param command String containing command to execute
666 -- @return String containing the command's stdout
667 function exec(command)
668 local pp = io.popen(command)
669 local data = pp:read("*a")
675 --- Return a line-buffered iterator over the output of given command.
676 -- @param command String containing the command to execute
678 function execi(command)
679 local pp = io.popen(command)
681 return pp and function()
682 local line = pp:read()
693 function execl(command)
694 local pp = io.popen(command)
700 if (line == nil) then break end
708 --- Returns the absolute path to LuCI base directory.
709 -- @return String containing the directory path
711 return require "nixio.fs".dirname(ldebug.__file__)
716 -- Coroutine safe xpcall and pcall versions modified for Luci
718 -- coxpcall 1.13 - Copyright 2005 - Kepler Project (www.keplerproject.org)
720 -- Copyright © 2005 Kepler Project.
721 -- Permission is hereby granted, free of charge, to any person obtaining a
722 -- copy of this software and associated documentation files (the "Software"),
723 -- to deal in the Software without restriction, including without limitation
724 -- the rights to use, copy, modify, merge, publish, distribute, sublicense,
725 -- and/or sell copies of the Software, and to permit persons to whom the
726 -- Software is furnished to do so, subject to the following conditions:
728 -- The above copyright notice and this permission notice shall be
729 -- included in all copies or substantial portions of the Software.
731 -- THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
732 -- EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
733 -- OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
734 -- IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
735 -- DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
736 -- TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE
737 -- OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
739 local performResume, handleReturnValue
740 local oldpcall, oldxpcall = pcall, xpcall
742 setmetatable(coxpt, {__mode = "kv"})
744 -- Identity function for copcall
745 local function copcall_id(trace, ...)
749 --- This is a coroutine-safe drop-in replacement for Lua's "xpcall"-function
750 -- @param f Lua function to be called protected
751 -- @param err Custom error handler
752 -- @param ... Parameters passed to the function
753 -- @return A boolean whether the function call succeeded and the return
754 -- values of either the function or the error handler
755 function coxpcall(f, err, ...)
756 local res, co = oldpcall(coroutine.create, f)
759 local newf = function() return f(unpack(params)) end
760 co = coroutine.create(newf)
762 local c = coroutine.running()
763 coxpt[co] = coxpt[c] or c or 0
765 return performResume(err, co, ...)
768 --- This is a coroutine-safe drop-in replacement for Lua's "pcall"-function
769 -- @param f Lua function to be called protected
770 -- @param ... Parameters passed to the function
771 -- @return A boolean whether the function call succeeded and the returns
772 -- values of the function or the error object
773 function copcall(f, ...)
774 return coxpcall(f, copcall_id, ...)
777 -- Handle return value of protected call
778 function handleReturnValue(err, co, status, ...)
780 return false, err(debug.traceback(co, (...)), ...)
783 if coroutine.status(co) ~= 'suspended' then
787 return performResume(err, co, coroutine.yield(...))
790 -- Resume execution of protected function call
791 function performResume(err, co, ...)
792 return handleReturnValue(err, co, coroutine.resume(co, ...))