5 Several common useful Lua functions
8 Copyright 2008 Steven Barth <steven@midlink.org>
10 Licensed under the Apache License, Version 2.0 (the "License");
11 you may not use this file except in compliance with the License.
12 You may obtain a copy of the License at
14 http://www.apache.org/licenses/LICENSE-2.0
16 Unless required by applicable law or agreed to in writing, software
17 distributed under the License is distributed on an "AS IS" BASIS,
18 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
19 See the License for the specific language governing permissions and
20 limitations under the License.
24 local io = require "io"
25 local math = require "math"
26 local table = require "table"
27 local debug = require "debug"
28 local ldebug = require "luci.debug"
29 local string = require "string"
30 local coroutine = require "coroutine"
31 local tparser = require "luci.template.parser"
33 local getmetatable, setmetatable = getmetatable, setmetatable
34 local rawget, rawset, unpack = rawget, rawset, unpack
35 local tostring, type, assert = tostring, type, assert
36 local ipairs, pairs, next, loadstring = ipairs, pairs, next, loadstring
37 local require, pcall, xpcall = require, pcall, xpcall
38 local collectgarbage, get_memory_limit = collectgarbage, get_memory_limit
40 --- LuCI utility functions.
44 -- Pythonic string formatting extension
46 getmetatable("").__mod = function(a, b)
49 elseif type(b) == "table" then
50 for k, _ in pairs(b) do if type(b[k]) == "userdata" then b[k] = tostring(b[k]) end end
51 return a:format(unpack(b))
53 if type(b) == "userdata" then b = tostring(b) end
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
120 __index = function(self, key)
121 local t = rawget(self, coxpt[coroutine.running()]
122 or coroutine.running() or 0)
126 __newindex = function(self, key, value)
127 local c = coxpt[coroutine.running()] or coroutine.running() or 0
128 local r = rawget(self, c)
130 rawset(self, c, { [key] = value })
137 --- Create a new or get an already existing thread local store associated with
138 -- the current active coroutine. A thread local store is private a table object
139 -- whose values can't be accessed from outside of the running coroutine.
140 -- @return Table value representing the corresponding thread local store
141 function threadlocal(tbl)
142 return setmetatable(tbl or {}, tl_meta)
147 -- Debugging routines
150 --- Write given object to stderr.
151 -- @param obj Value to write to stderr
152 -- @return Boolean indicating whether the write operation was successful
154 return io.stderr:write(tostring(obj) .. "\n")
157 --- Recursively dumps a table to stdout, useful for testing and debugging.
158 -- @param t Table value to dump
159 -- @param maxdepth Maximum depth
160 -- @return Always nil
161 function dumptable(t, maxdepth, i, seen)
163 seen = seen or setmetatable({}, {__mode="k"})
165 for k,v in pairs(t) do
166 perror(string.rep("\t", i) .. tostring(k) .. "\t" .. tostring(v))
167 if type(v) == "table" and (not maxdepth or i < maxdepth) then
170 dumptable(v, maxdepth, i+1, seen)
172 perror(string.rep("\t", i) .. "*** RECURSION ***")
180 -- String and data manipulation routines
183 --- Create valid XML PCDATA from given string.
184 -- @param value String value containing the data to escape
185 -- @return String value containing the escaped data
186 function pcdata(value)
187 return value and tparser.pcdata(tostring(value))
190 --- Strip HTML tags from given string.
191 -- @param value String containing the HTML text
192 -- @return String with HTML tags stripped of
193 function striptags(value)
194 return value and tparser.striptags(tostring(value))
197 --- Splits given string on a defined separator sequence and return a table
198 -- containing the resulting substrings. The optional max parameter specifies
199 -- the number of bytes to process, regardless of the actual length of the given
200 -- string. The optional last parameter, regex, specifies whether the separator
201 -- sequence is interpreted as regular expression.
202 -- @param str String value containing the data to split up
203 -- @param pat String with separator pattern (optional, defaults to "\n")
204 -- @param max Maximum times to split (optional)
205 -- @param regex Boolean indicating whether to interpret the separator
206 -- pattern as regular expression (optional, default is false)
207 -- @return Table containing the resulting substrings
208 function split(str, pat, max, regex)
228 local s, e = str:find(pat, c, not regex)
230 if s and max < 0 then
233 t[#t+1] = str:sub(c, s and s - 1)
235 c = e and e + 1 or #str + 1
236 until not s or max < 0
241 --- Remove leading and trailing whitespace from given string value.
242 -- @param str String value containing whitespace padded data
243 -- @return String value with leading and trailing space removed
245 return (str:gsub("^%s*(.-)%s*$", "%1"))
248 --- Count the occurences of given substring in given string.
249 -- @param str String to search in
250 -- @param pattern String containing pattern to find
251 -- @return Number of found occurences
252 function cmatch(str, pat)
254 for _ in str:gmatch(pat) do count = count + 1 end
258 --- Return a matching iterator for the given value. The iterator will return
259 -- one token per invocation, the tokens are separated by whitespace. If the
260 -- input value is a table, it is transformed into a string first. A nil value
261 -- will result in a valid interator which aborts with the first invocation.
262 -- @param val The value to scan (table, string or nil)
263 -- @return Iterator which returns one token per call
265 if type(v) == "table" then
272 elseif type(v) == "number" or type(v) == "boolean" then
281 elseif type(v) == "userdata" or type(v) == "string" then
282 return tostring(v):gmatch("%S+")
285 return function() end
288 --- Parse certain units from the given string and return the canonical integer
289 -- value or 0 if the unit is unknown. Upper- or lower case is irrelevant.
290 -- Recognized units are:
291 -- o "y" - one year (60*60*24*366)
292 -- o "m" - one month (60*60*24*31)
293 -- o "w" - one week (60*60*24*7)
294 -- o "d" - one day (60*60*24)
295 -- o "h" - one hour (60*60)
296 -- o "min" - one minute (60)
297 -- o "kb" - one kilobyte (1024)
298 -- o "mb" - one megabyte (1024*1024)
299 -- o "gb" - one gigabyte (1024*1024*1024)
300 -- o "kib" - one si kilobyte (1000)
301 -- o "mib" - one si megabyte (1000*1000)
302 -- o "gib" - one si gigabyte (1000*1000*1000)
303 -- @param ustr String containing a numerical value with trailing unit
304 -- @return Number containing the canonical value
305 function parse_units(ustr)
312 y = 60 * 60 * 24 * 366,
313 m = 60 * 60 * 24 * 31,
314 w = 60 * 60 * 24 * 7,
322 gb = 1024 * 1024 * 1024,
324 -- storage sizes (si)
327 gib = 1000 * 1000 * 1000
330 -- parse input string
331 for spec in ustr:lower():gmatch("[0-9%.]+[a-zA-Z]*") do
333 local num = spec:gsub("[^0-9%.]+$","")
334 local spn = spec:gsub("^[0-9%.]+", "")
336 if map[spn] or map[spn:sub(1,1)] then
337 val = val + num * ( map[spn] or map[spn:sub(1,1)] )
347 -- also register functions above in the central string class for convenience
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 )
611 for k, v in pairs(t) do
617 table.sort( keys, f )
621 if _pos <= #keys then
622 return keys[_pos], t[keys[_pos]], _pos
627 --- Return a key, value iterator which returns the values sorted according to
628 -- the provided callback function.
629 -- @param t The table to iterate
630 -- @param f A callback function to decide the order of elements
631 -- @return Function value containing the corresponding iterator
633 return _sortiter( t, f )
636 --- Return a key, value iterator for the given table.
637 -- The table pairs are sorted by key.
638 -- @param t The table to iterate
639 -- @return Function value containing the corresponding iterator
641 return _sortiter( t )
644 --- Return a key, value iterator for the given table.
645 -- The table pairs are sorted by value.
646 -- @param t The table to iterate
647 -- @return Function value containing the corresponding iterator
649 return _sortiter( t, function (a,b) return t[a] < t[b] end )
654 -- System utility functions
657 --- Test whether the current system is operating in big endian mode.
658 -- @return Boolean value indicating whether system is big endian
660 return string.byte(string.dump(function() end), 7) == 0
663 --- Execute given commandline and gather stdout.
664 -- @param command String containing command to execute
665 -- @return String containing the command's stdout
666 function exec(command)
667 local pp = io.popen(command)
668 local data = pp:read("*a")
674 --- Return a line-buffered iterator over the output of given command.
675 -- @param command String containing the command to execute
677 function execi(command)
678 local pp = io.popen(command)
680 return pp and function()
681 local line = pp:read()
692 function execl(command)
693 local pp = io.popen(command)
699 if (line == nil) then break end
707 --- Returns the absolute path to LuCI base directory.
708 -- @return String containing the directory path
710 return require "nixio.fs".dirname(ldebug.__file__)
715 -- Coroutine safe xpcall and pcall versions modified for Luci
717 -- coxpcall 1.13 - Copyright 2005 - Kepler Project (www.keplerproject.org)
719 -- Copyright © 2005 Kepler Project.
720 -- Permission is hereby granted, free of charge, to any person obtaining a
721 -- copy of this software and associated documentation files (the "Software"),
722 -- to deal in the Software without restriction, including without limitation
723 -- the rights to use, copy, modify, merge, publish, distribute, sublicense,
724 -- and/or sell copies of the Software, and to permit persons to whom the
725 -- Software is furnished to do so, subject to the following conditions:
727 -- The above copyright notice and this permission notice shall be
728 -- included in all copies or substantial portions of the Software.
730 -- THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
731 -- EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
732 -- OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
733 -- IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
734 -- DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
735 -- TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE
736 -- OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
738 local performResume, handleReturnValue
739 local oldpcall, oldxpcall = pcall, xpcall
741 setmetatable(coxpt, {__mode = "kv"})
743 -- Identity function for copcall
744 local function copcall_id(trace, ...)
748 --- This is a coroutine-safe drop-in replacement for Lua's "xpcall"-function
749 -- @param f Lua function to be called protected
750 -- @param err Custom error handler
751 -- @param ... Parameters passed to the function
752 -- @return A boolean whether the function call succeeded and the return
753 -- values of either the function or the error handler
754 function coxpcall(f, err, ...)
755 local res, co = oldpcall(coroutine.create, f)
758 local newf = function() return f(unpack(params)) end
759 co = coroutine.create(newf)
761 local c = coroutine.running()
762 coxpt[co] = coxpt[c] or c or 0
764 return performResume(err, co, ...)
767 --- This is a coroutine-safe drop-in replacement for Lua's "pcall"-function
768 -- @param f Lua function to be called protected
769 -- @param ... Parameters passed to the function
770 -- @return A boolean whether the function call succeeded and the returns
771 -- values of the function or the error object
772 function copcall(f, ...)
773 return coxpcall(f, copcall_id, ...)
776 -- Handle return value of protected call
777 function handleReturnValue(err, co, status, ...)
779 return false, err(debug.traceback(co, (...)), ...)
782 if coroutine.status(co) ~= 'suspended' then
786 return performResume(err, co, coroutine.yield(...))
789 -- Resume execution of protected function call
790 function performResume(err, co, ...)
791 return handleReturnValue(err, co, coroutine.resume(co, ...))