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 getfenv, setfenv = getfenv, setfenv
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
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 function pcdata(value)
198 return value and tostring(value):gsub("[&\"'<>]", {
207 --- Strip HTML tags from given string.
208 -- @param value String containing the HTML text
209 -- @return String with HTML tags stripped of
210 function striptags(s)
211 return pcdata(s:gsub("</?[A-Za-z][A-Za-z0-9:_%-]*[^>]*>", " "):gsub("%s+", " "))
214 --- Splits given string on a defined separator sequence and return a table
215 -- containing the resulting substrings. The optional max parameter specifies
216 -- the number of bytes to process, regardless of the actual length of the given
217 -- string. The optional last parameter, regex, specifies whether the separator
218 -- sequence is interpreted as regular expression.
219 -- @param str String value containing the data to split up
220 -- @param pat String with separator pattern (optional, defaults to "\n")
221 -- @param max Maximum times to split (optional)
222 -- @param regex Boolean indicating whether to interpret the separator
223 -- pattern as regular expression (optional, default is false)
224 -- @return Table containing the resulting substrings
225 function split(str, pat, max, regex)
245 local s, e = str:find(pat, c, not regex)
247 if s and max < 0 then
250 t[#t+1] = str:sub(c, s and s - 1)
252 c = e and e + 1 or #str + 1
253 until not s or max < 0
258 --- Remove leading and trailing whitespace from given string value.
259 -- @param str String value containing whitespace padded data
260 -- @return String value with leading and trailing space removed
262 return (str:gsub("^%s*(.-)%s*$", "%1"))
265 --- Parse certain units from the given string and return the canonical integer
266 -- value or 0 if the unit is unknown. Upper- or lower case is irrelevant.
267 -- Recognized units are:
268 -- o "y" - one year (60*60*24*366)
269 -- o "m" - one month (60*60*24*31)
270 -- o "w" - one week (60*60*24*7)
271 -- o "d" - one day (60*60*24)
272 -- o "h" - one hour (60*60)
273 -- o "min" - one minute (60)
274 -- o "kb" - one kilobyte (1024)
275 -- o "mb" - one megabyte (1024*1024)
276 -- o "gb" - one gigabyte (1024*1024*1024)
277 -- o "kib" - one si kilobyte (1000)
278 -- o "mib" - one si megabyte (1000*1000)
279 -- o "gib" - one si gigabyte (1000*1000*1000)
280 -- @param ustr String containing a numerical value with trailing unit
281 -- @return Number containing the canonical value
282 function parse_units(ustr)
289 y = 60 * 60 * 24 * 366,
290 m = 60 * 60 * 24 * 31,
291 w = 60 * 60 * 24 * 7,
299 gb = 1024 * 1024 * 1024,
301 -- storage sizes (si)
304 gib = 1000 * 1000 * 1000
307 -- parse input string
308 for spec in ustr:lower():gmatch("[0-9%.]+[a-zA-Z]*") do
310 local num = spec:gsub("[^0-9%.]+$","")
311 local spn = spec:gsub("^[0-9%.]+", "")
313 if map[spn] or map[spn:sub(1,1)] then
314 val = val + num * ( map[spn] or map[spn:sub(1,1)] )
324 --- Combines two or more numerically indexed tables into one.
325 -- @param tbl1 Table value to combine
326 -- @param tbl2 Table value to combine
327 -- @param ... More tables to combine
328 -- @return Table value containing all values of given tables
329 function combine(...)
331 for i, a in ipairs(arg) do
332 for j, v in ipairs(a) do
333 result[#result+1] = v
339 --- Checks whether the given table contains the given value.
340 -- @param table Table value
341 -- @param value Value to search within the given table
342 -- @return Boolean indicating whether the given value occurs within table
343 function contains(table, value)
344 for k, v in pairs(table) do
352 --- Update values in given table with the values from the second given table.
353 -- Both table are - in fact - merged together.
354 -- @param t Table which should be updated
355 -- @param updates Table containing the values to update
356 -- @return Always nil
357 function update(t, updates)
358 for k, v in pairs(updates) do
363 --- Retrieve all keys of given associative table.
364 -- @param t Table to extract keys from
365 -- @return Sorted table containing the keys
369 for k, _ in kspairs(t) do
376 --- Clones the given object and return it's copy.
377 -- @param object Table value to clone
378 -- @param deep Boolean indicating whether to do recursive cloning
379 -- @return Cloned table value
380 function clone(object, deep)
383 for k, v in pairs(object) do
384 if deep and type(v) == "table" then
390 return setmetatable(copy, getmetatable(object))
394 --- Create a dynamic table which automatically creates subtables.
395 -- @return Dynamic Table
397 return setmetatable({}, { __index =
399 return rawget(tbl, key)
400 or rawget(rawset(tbl, key, dtable()), key)
406 -- Serialize the contents of a table value.
407 function _serialize_table(t, seen)
408 assert(not seen[t], "Recursion detected.")
415 for k, v in pairs(t) do
416 if type(k) ~= "number" or k < 1 or math.floor(k) ~= k or ( k - #t ) > 3 then
417 k = serialize_data(k, seen)
418 v = serialize_data(v, seen)
419 data = data .. ( #data > 0 and ", " or "" ) ..
420 '[' .. k .. '] = ' .. v
427 local v = serialize_data(t[i], seen)
428 idata = idata .. ( #idata > 0 and ", " or "" ) .. v
431 return idata .. ( #data > 0 and #idata > 0 and ", " or "" ) .. data
434 --- Recursively serialize given data to lua code, suitable for restoring
435 -- with loadstring().
436 -- @param val Value containing the data to serialize
437 -- @return String value containing the serialized code
440 function serialize_data(val, seen)
441 seen = seen or setmetatable({}, {__mode="k"})
445 elseif type(val) == "number" then
447 elseif type(val) == "string" then
449 elseif type(val) == "boolean" then
450 return val and "true" or "false"
451 elseif type(val) == "function" then
452 return "loadstring(%q)" % get_bytecode(val)
453 elseif type(val) == "table" then
454 return "{ " .. _serialize_table(val, seen) .. " }"
456 return '"[unhandled data type:' .. type(val) .. ']"'
460 --- Restore data previously serialized with serialize_data().
461 -- @param str String containing the data to restore
462 -- @return Value containing the restored data structure
463 -- @see serialize_data
465 function restore_data(str)
466 return loadstring("return " .. str)()
471 -- Byte code manipulation routines
474 --- Return the current runtime bytecode of the given data. The byte code
475 -- will be stripped before it is returned.
476 -- @param val Value to return as bytecode
477 -- @return String value containing the bytecode of the given data
478 function get_bytecode(val)
481 if type(val) == "function" then
482 code = string.dump(val)
484 code = string.dump( loadstring( "return " .. serialize_data(val) ) )
487 return code and strip_bytecode(code)
490 --- Strips unnescessary lua bytecode from given string. Information like line
491 -- numbers and debugging numbers will be discarded. Original version by
492 -- Peter Cawley (http://lua-users.org/lists/lua-l/2008-02/msg01158.html)
493 -- @param code String value containing the original lua byte code
494 -- @return String value containing the stripped lua byte code
495 function strip_bytecode(code)
496 local version, format, endian, int, size, ins, num, lnum = code:byte(5, 12)
499 subint = function(code, i, l)
502 val = val * 256 + code:byte(i + n - 1)
507 subint = function(code, i, l)
510 val = val * 256 + code:byte(i + n - 1)
517 strip_function = function(code)
518 local count, offset = subint(code, 1, size)
519 local stripped, dirty = string.rep("\0", size), offset + count
520 offset = offset + count + int * 2 + 4
521 offset = offset + int + subint(code, offset, int) * ins
522 count, offset = subint(code, offset, int)
525 t, offset = subint(code, offset, 1)
529 offset = offset + size + subint(code, offset, size)
531 offset = offset + num
532 elseif t == 254 or t == 9 then
533 offset = offset + lnum
536 count, offset = subint(code, offset, int)
537 stripped = stripped .. code:sub(dirty, offset - 1)
539 local proto, off = strip_function(code:sub(offset, -1))
540 stripped, offset = stripped .. proto, offset + off - 1
542 offset = offset + subint(code, offset, int) * int + int
543 count, offset = subint(code, offset, int)
545 offset = offset + subint(code, offset, size) + size + int * 2
547 count, offset = subint(code, offset, int)
549 offset = offset + subint(code, offset, size) + size
551 stripped = stripped .. string.rep("\0", int * 3)
552 return stripped, offset
555 return code:sub(1,12) .. strip_function(code:sub(13,-1))
560 -- Sorting iterator functions
563 function _sortiter( t, f )
566 for k, v in pairs(t) do
572 table.sort( keys, f )
576 if _pos <= #keys then
577 return keys[_pos], t[keys[_pos]]
582 --- Return a key, value iterator which returns the values sorted according to
583 -- the provided callback function.
584 -- @param t The table to iterate
585 -- @param f A callback function to decide the order of elements
586 -- @return Function value containing the corresponding iterator
588 return _sortiter( t, f )
591 --- Return a key, value iterator for the given table.
592 -- The table pairs are sorted by key.
593 -- @param t The table to iterate
594 -- @return Function value containing the corresponding iterator
596 return _sortiter( t )
599 --- Return a key, value iterator for the given table.
600 -- The table pairs are sorted by value.
601 -- @param t The table to iterate
602 -- @return Function value containing the corresponding iterator
604 return _sortiter( t, function (a,b) return t[a] < t[b] end )
609 -- System utility functions
612 --- Test whether the current system is operating in big endian mode.
613 -- @return Boolean value indicating whether system is big endian
615 return string.byte(string.dump(function() end), 7) == 0
618 --- Execute given commandline and gather stdout.
619 -- @param command String containing command to execute
620 -- @return String containing the command's stdout
621 function exec(command)
622 local pp = io.popen(command)
623 local data = pp:read("*a")
629 --- Return a line-buffered iterator over the output of given command.
630 -- @param command String containing the command to execute
632 function execi(command)
633 local pp = io.popen(command)
635 return pp and function()
636 local line = pp:read()
647 function execl(command)
648 local pp = io.popen(command)
654 if (line == nil) then break end
662 --- Returns the absolute path to LuCI base directory.
663 -- @return String containing the directory path
665 return require "luci.fs".dirname(ldebug.__file__)
670 -- Coroutine safe xpcall and pcall versions modified for Luci
672 -- coxpcall 1.13 - Copyright 2005 - Kepler Project (www.keplerproject.org)
674 -- Copyright © 2005 Kepler Project.
675 -- Permission is hereby granted, free of charge, to any person obtaining a
676 -- copy of this software and associated documentation files (the "Software"),
677 -- to deal in the Software without restriction, including without limitation
678 -- the rights to use, copy, modify, merge, publish, distribute, sublicense,
679 -- and/or sell copies of the Software, and to permit persons to whom the
680 -- Software is furnished to do so, subject to the following conditions:
682 -- The above copyright notice and this permission notice shall be
683 -- included in all copies or substantial portions of the Software.
685 -- THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
686 -- EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
687 -- OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
688 -- IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
689 -- DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
690 -- TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE
691 -- OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
693 local performResume, handleReturnValue
694 local oldpcall, oldxpcall = pcall, xpcall
696 setmetatable(coxpt, {__mode = "kv"})
698 -- Identity function for copcall
699 local function copcall_id(trace, ...)
703 --- This is a coroutine-safe drop-in replacement for Lua's "xpcall"-function
704 -- @param f Lua function to be called protected
705 -- @param err Custom error handler
706 -- @param ... Parameters passed to the function
707 -- @return A boolean whether the function call succeeded and the return
708 -- values of either the function or the error handler
709 function coxpcall(f, err, ...)
710 local res, co = oldpcall(coroutine.create, f)
713 local newf = function() return f(unpack(params)) end
714 co = coroutine.create(newf)
716 local c = coroutine.running()
717 coxpt[co] = coxpt[c] or c or 0
719 return performResume(err, co, ...)
722 --- This is a coroutine-safe drop-in replacement for Lua's "pcall"-function
723 -- @param f Lua function to be called protected
724 -- @param ... Parameters passed to the function
725 -- @return A boolean whether the function call succeeded and the returns
726 -- values of the function or the error object
727 function copcall(f, ...)
728 return coxpcall(f, copcall_id, ...)
731 -- Handle return value of protected call
732 function handleReturnValue(err, co, status, ...)
734 return false, err(debug.traceback(co, (...)), ...)
736 if coroutine.status(co) == 'suspended' then
737 return performResume(err, co, coroutine.yield(...))
743 -- Resume execution of protected function call
744 function performResume(err, co, ...)
745 return handleReturnValue(err, co, coroutine.resume(co, ...))