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 --- LuCI utility functions.
28 module("luci.util", package.seeall)
31 -- Class helper routines
34 --- Create a Class object (Python-style object model).
35 -- The class object can be instantiated by calling itself.
36 -- Any class functions or shared parameters can be attached to this object.
37 -- Attaching a table to the class object makes this table shared between
38 -- all instances of this class. For object parameters use the __init__ function.
39 -- Classes can inherit member functions and values from a base class.
40 -- Class can be instantiated by calling them. All parameters will be passed
41 -- to the __init__ function of this class - if such a function exists.
42 -- The __init__ function must be used to set any object parameters that are not shared
43 -- with other objects of this class. Any return values will be ignored.
44 -- @param base The base class to inherit from (optional)
45 -- @return A class object
51 local create = function(class, ...)
53 setmetatable(inst, {__index = class})
56 local stat, err = copcall(inst.__init__, inst, ...)
65 local classmeta = {__call = create}
68 classmeta.__index = base
71 setmetatable(class, classmeta)
75 --- Test whether the given object is an instance of the given class.
76 -- @param object Object instance
77 -- @param class Class object to test against
78 -- @return Boolean indicating whether the object is an instance
81 function instanceof(object, class)
82 local meta = getmetatable(object)
83 while meta and meta.__index do
84 if meta.__index == class then
87 meta = getmetatable(meta.__index)
94 -- Scope manipulation routines
97 --- Replace a function scope with a shallow copy of itself.
98 -- This is useful if you want to get rid of several unwanted side effects
99 -- while changing the scope of a certain Lua function.
100 -- @param f Lua function
102 setfenv(f, clone(getfenv(f)))
105 --- Store given object associated with given key in the scope of a function.
106 -- @param f Lua function
107 -- @param key String value containg the key of the object to store
108 -- @param obj Object to store in the scope
109 -- @return Always nil
112 function extfenv(f, key, obj)
113 local scope = getfenv(f)
117 --- Extend the scope of a function with the contents of a table
118 -- @param f Lua function
119 -- @param key String value containg the key of the object to store
120 -- @param obj Object to store in the scope
121 -- @return Always nil
124 function updfenv(f, extscope)
125 update(getfenv(f), extscope)
128 --- Create a new or get an already existing thread local store associated with
129 -- the current active coroutine. A thread local store is private a table object
130 -- whose values can't be accessed from outside of the running coroutine.
131 -- @return Table value representing the corresponding thread local store
132 function threadlocal()
135 local function get(self, key)
136 local c = coroutine.running()
137 local thread = coxpt[c] or c or 0
138 if not rawget(self, thread) then
141 return rawget(self, thread)[key]
144 local function set(self, key, value)
145 local c = coroutine.running()
146 local thread = coxpt[c] or c or 0
147 if not rawget(self, thread) then
148 rawset(self, thread, {})
150 rawget(self, thread)[key] = value
153 setmetatable(tbl, {__index = get, __newindex = set, __mode = "k"})
160 -- Debugging routines
163 --- Write given object to stderr.
164 -- @param obj Value to write to stderr
165 -- @return Boolean indicating whether the write operation was successful
167 return io.stderr:write(tostring(obj) .. "\n")
170 --- Recursively dumps a table to stdout, useful for testing and debugging.
171 -- @param t Table value to dump
172 -- @param i Number of tabs to prepend to each line
173 -- @return Always nil
174 function dumptable(t, i)
176 for k,v in pairs(t) do
177 print(string.rep("\t", i) .. tostring(k), tostring(v))
178 if type(v) == "table" then
186 -- String and data manipulation routines
189 --- Escapes all occurrences of the given character in given string.
190 -- @param s String value containing unescaped characters
191 -- @param c String value with character to escape (optional, defaults to "\")
192 -- @return String value with each occurrence of character escaped with "\"
193 function escape(s, c)
195 return s:gsub(c, "\\" .. c)
198 --- Create valid XML PCDATA from given string.
199 -- @param value String value containing the data to escape
200 -- @return String value containing the escaped data
201 function pcdata(value)
202 if not value then return end
203 value = tostring(value)
204 value = value:gsub("&", "&")
205 value = value:gsub('"', """)
206 value = value:gsub("'", "'")
207 value = value:gsub("<", "<")
208 return value:gsub(">", ">")
211 --- Splits given string on a defined separator sequence and return a table
212 -- containing the resulting substrings. The optional max parameter specifies
213 -- the number of bytes to process, regardless of the actual length of the given
214 -- string. The optional last parameter, regex, specifies whether the separator
215 -- sequence is interpreted as regular expression.
216 -- @param str String value containing the data to split up
217 -- @param pat String with separator pattern (optional, defaults to "\n")
218 -- @param max Maximum times to split (optional)
219 -- @param regex Boolean indicating whether to interpret the separator
220 -- pattern as regular expression (optional, default is false)
221 -- @return Table containing the resulting substrings
222 function split(str, pat, max, regex)
242 local s, e = str:find(pat, c, not regex)
244 if s and max < 0 then
245 table.insert(t, str:sub(c))
247 table.insert(t, str:sub(c, s and s - 1))
249 c = e and e + 1 or #str + 1
250 until not s or max < 0
255 --- Remove leading and trailing whitespace from given string value.
256 -- @param str String value containing whitespace padded data
257 -- @return String value with leading and trailing space removed
259 local s = str:gsub("^%s*(.-)%s*$", "%1")
263 --- Parse certain units from the given string and return the canonical integer
264 -- value or 0 if the unit is unknown. Upper- or lower case is irrelevant.
265 -- Recognized units are:
266 -- o "y" - one year (60*60*24*366)
267 -- o "m" - one month (60*60*24*31)
268 -- o "w" - one week (60*60*24*7)
269 -- o "d" - one day (60*60*24)
270 -- o "h" - one hour (60*60)
271 -- o "min" - one minute (60)
272 -- o "kb" - one kilobyte (1024)
273 -- o "mb" - one megabyte (1024*1024)
274 -- o "gb" - one gigabyte (1024*1024*1024)
275 -- o "kib" - one si kilobyte (1000)
276 -- o "mib" - one si megabyte (1000*1000)
277 -- o "gib" - one si gigabyte (1000*1000*1000)
278 -- @param ustr String containing a numerical value with trailing unit
279 -- @return Number containing the canonical value
280 function parse_units(ustr)
287 y = 60 * 60 * 24 * 366,
288 m = 60 * 60 * 24 * 31,
289 w = 60 * 60 * 24 * 7,
297 gb = 1024 * 1024 * 1024,
299 -- storage sizes (si)
302 gib = 1000 * 1000 * 1000
305 -- parse input string
306 for spec in ustr:lower():gmatch("[0-9%.]+[a-zA-Z]*") do
308 local num = spec:gsub("[^0-9%.]+$","")
309 local spn = spec:gsub("^[0-9%.]+", "")
311 if map[spn] or map[spn:sub(1,1)] then
312 val = val + num * ( map[spn] or map[spn:sub(1,1)] )
322 --- Combines two or more numerically indexed tables into one.
323 -- @param tbl1 Table value to combine
324 -- @param tbl2 Table value to combine
325 -- @param ... More tables to combine
326 -- @return Table value containing all values of given tables
327 function combine(...)
329 for i, a in ipairs(arg) do
330 for j, v in ipairs(a) do
331 table.insert(result, v)
337 --- Checks whether the given table contains the given value.
338 -- @param table Table value
339 -- @param value Value to search within the given table
340 -- @return Boolean indicating whether the given value occurs within table
341 function contains(table, value)
342 for k, v in pairs(table) do
350 --- Update values in given table with the values from the second given table.
351 -- Both table are - in fact - merged together.
352 -- @param t Table which should be updated
353 -- @param updates Table containing the values to update
354 -- @return Always nil
355 function update(t, updates)
356 for k, v in pairs(updates) do
361 --- Retrieve all keys of given associative table.
362 -- @param t Table to extract keys from
363 -- @return Sorted table containing the keys
367 for k, _ in kspairs(t) do
368 table.insert( keys, k )
374 --- Clones the given object and return it's copy.
375 -- @param object Table value to clone
376 -- @param deep Boolean indicating whether to do recursive cloning
377 -- @return Cloned table value
378 function clone(object, deep)
381 for k, v in pairs(object) do
382 if deep and type(v) == "table" then
388 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)
409 for k, v in pairs(t) do
410 k = serialize_data(k)
411 v = serialize_data(v)
412 data = data .. ( #data > 0 and ", " or "" ) ..
413 '[' .. k .. '] = ' .. v
418 --- Recursively serialize given data to lua code, suitable for restoring
419 -- with loadstring().
420 -- @param val Value containing the data to serialize
421 -- @return String value containing the serialized code
424 function serialize_data(val)
427 elseif type(val) == "number" then
429 elseif type(val) == "string" then
430 return string.format("%q", val)
431 elseif type(val) == "boolean" then
432 return val and "true" or "false"
433 elseif type(val) == "function" then
434 return string.format("loadstring(%q)", get_bytecode(val))
435 elseif type(val) == "table" then
436 return "{ " .. _serialize_table(val) .. " }"
438 return '"[unhandled data type:' .. type(val) .. ']"'
442 --- Restore data previously serialized with serialize_data().
443 -- @param str String containing the data to restore
444 -- @return Value containing the restored data structure
445 -- @see serialize_data
447 function restore_data(str)
448 return loadstring("return " .. str)()
453 -- Byte code manipulation routines
456 --- Return the current runtime bytecode of the given data. The byte code
457 -- will be stripped before it is returned.
458 -- @param val Value to return as bytecode
459 -- @return String value containing the bytecode of the given data
460 function get_bytecode(val)
463 if type(val) == "function" then
464 code = string.dump(val)
466 code = string.dump( loadstring( "return " .. serialize_data(val) ) )
469 return code and strip_bytecode(code)
472 --- Strips unnescessary lua bytecode from given string. Information like line
473 -- numbers and debugging numbers will be discarded. Original version by
474 -- Peter Cawley (http://lua-users.org/lists/lua-l/2008-02/msg01158.html)
475 -- @param code String value containing the original lua byte code
476 -- @return String value containing the stripped lua byte code
477 function strip_bytecode(code)
478 local version, format, endian, int, size, ins, num, lnum = code:byte(5, 12)
481 subint = function(code, i, l)
484 val = val * 256 + code:byte(i + n - 1)
489 subint = function(code, i, l)
492 val = val * 256 + code:byte(i + n - 1)
499 strip_function = function(code)
500 local count, offset = subint(code, 1, size)
501 local stripped, dirty = string.rep("\0", size), offset + count
502 offset = offset + count + int * 2 + 4
503 offset = offset + int + subint(code, offset, int) * ins
504 count, offset = subint(code, offset, int)
507 t, offset = subint(code, offset, 1)
511 offset = offset + size + subint(code, offset, size)
513 offset = offset + num
514 elseif t == 254 or t == 9 then
515 offset = offset + lnum
518 count, offset = subint(code, offset, int)
519 stripped = stripped .. code:sub(dirty, offset - 1)
521 local proto, off = strip_function(code:sub(offset, -1))
522 stripped, offset = stripped .. proto, offset + off - 1
524 offset = offset + subint(code, offset, int) * int + int
525 count, offset = subint(code, offset, int)
527 offset = offset + subint(code, offset, size) + size + int * 2
529 count, offset = subint(code, offset, int)
531 offset = offset + subint(code, offset, size) + size
533 stripped = stripped .. string.rep("\0", int * 3)
534 return stripped, offset
537 return code:sub(1,12) .. strip_function(code:sub(13,-1))
542 -- Sorting iterator functions
545 function _sortiter( t, f )
548 for k, v in pairs(t) do
549 table.insert( keys, k )
553 local _len = table.getn( keys )
555 table.sort( keys, f )
560 return keys[_pos], t[keys[_pos]]
565 --- Return a key, value iterator which returns the values sorted according to
566 -- the provided callback function.
567 -- @param t The table to iterate
568 -- @param f A callback function to decide the order of elements
569 -- @return Function value containing the corresponding iterator
571 return _sortiter( t, f )
574 --- Return a key, value iterator for the given table.
575 -- The table pairs are sorted by key.
576 -- @param t The table to iterate
577 -- @return Function value containing the corresponding iterator
579 return _sortiter( t )
582 --- Return a key, value iterator for the given table.
583 -- The table pairs are sorted by value.
584 -- @param t The table to iterate
585 -- @return Function value containing the corresponding iterator
587 return _sortiter( t, function (a,b) return t[a] < t[b] end )
592 -- System utility functions
595 --- Test whether the current system is operating in big endian mode.
596 -- @return Boolean value indicating whether system is big endian
598 return string.byte(string.dump(function() end), 7) == 0
601 --- Execute given commandline and gather stdout.
602 -- @param command String containing command to execute
603 -- @return String containing the command's stdout
604 function exec(command)
605 local pp = io.popen(command)
606 local data = pp:read("*a")
612 --- Return a line-buffered iterator over the output of given command.
613 -- @param command String containing the command to execute
615 function execi(command)
616 local pp = io.popen(command)
618 return pp and function()
619 local line = pp:read()
630 function execl(command)
631 local pp = io.popen(command)
637 if (line == nil) then break end
638 table.insert(data, line)
645 --- Returns the absolute path to LuCI base directory.
646 -- @return String containing the directory path
648 return luci.fs.dirname(require("luci.debug").__file__)
653 -- Coroutine safe xpcall and pcall versions modified for Luci
655 -- coxpcall 1.13 - Copyright 2005 - Kepler Project (www.keplerproject.org)
657 -- Copyright © 2005 Kepler Project.
658 -- Permission is hereby granted, free of charge, to any person obtaining a
659 -- copy of this software and associated documentation files (the "Software"),
660 -- to deal in the Software without restriction, including without limitation
661 -- the rights to use, copy, modify, merge, publish, distribute, sublicense,
662 -- and/or sell copies of the Software, and to permit persons to whom the
663 -- Software is furnished to do so, subject to the following conditions:
665 -- The above copyright notice and this permission notice shall be
666 -- included in all copies or substantial portions of the Software.
668 -- THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
669 -- EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
670 -- OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
671 -- IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
672 -- DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
673 -- TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE
674 -- OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
676 local performResume, handleReturnValue
677 local oldpcall, oldxpcall = pcall, xpcall
679 setmetatable(coxpt, {__mode = "kv"})
681 -- Identity function for copcall
682 local function copcall_id(trace, ...)
686 --- This is a coroutine-safe drop-in replacement for Lua's "xpcall"-function
687 -- @param f Lua function to be called protected
688 -- @param err Custom error handler
689 -- @param ... Parameters passed to the function
690 -- @return A boolean whether the function call succeeded and the return
691 -- values of either the function or the error handler
692 function coxpcall(f, err, ...)
693 local res, co = oldpcall(coroutine.create, f)
696 local newf = function() return f(unpack(params)) end
697 co = coroutine.create(newf)
699 local c = coroutine.running()
700 coxpt[co] = coxpt[c] or c or 0
702 return performResume(err, co, ...)
705 --- This is a coroutine-safe drop-in replacement for Lua's "pcall"-function
706 -- @param f Lua function to be called protected
707 -- @param ... Parameters passed to the function
708 -- @return A boolean whether the function call succeeded and the returns
709 -- values of the function or the error object
710 function copcall(f, ...)
711 return coxpcall(f, copcall_id, ...)
714 -- Handle return value of protected call
715 function handleReturnValue(err, co, status, ...)
717 return false, err(debug.traceback(co, (...)), ...)
719 if coroutine.status(co) == 'suspended' then
720 return performResume(err, co, coroutine.yield(...))
726 -- Resume execution of protected function call
727 function performResume(err, co, ...)
728 return handleReturnValue(err, co, coroutine.resume(co, ...))