libs/core/luasrc/util.lua

   1 --[[
   2 LuCI - Utility library
   3
   4 Description:
   5 Several common useful Lua functions
   6
   7 FileId:
   8 $Id$
   9
  10 License:
  11 Copyright 2008 Steven Barth <steven@midlink.org>
  12
  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
  16
  17         http://www.apache.org/licenses/LICENSE-2.0
  18
  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.
  24
  25 ]]--
  26
  27 module("luci.util", package.seeall)
  28
  29
  30 -- Lua simplified Python-style OO class support emulation
  31 function class(base)
  32         local class = {}
  33
  34         local create = function(class, ...)
  35                 local inst = {}
  36                 setmetatable(inst, {__index = class})
  37
  38                 if inst.__init__ then
  39                         local stat, err = pcall(inst.__init__, inst, ...)
  40                         if not stat then
  41                                 error(err)
  42                         end
  43                 end
  44
  45                 return inst
  46         end
  47
  48         local classmeta = {__call = create}
  49
  50         if base then
  51                 classmeta.__index = base
  52         end
  53
  54         setmetatable(class, classmeta)
  55         return class
  56 end
  57
  58
  59 -- Clones an object (deep on-demand)
  60 function clone(object, deep)
  61         local copy = {}
  62
  63         for k, v in pairs(object) do
  64                 if deep and type(v) == "table" then
  65                         v = clone(v, deep)
  66                 end
  67                 copy[k] = v
  68         end
  69
  70         setmetatable(copy, getmetatable(object))
  71
  72         return copy
  73 end
  74
  75
  76 -- Combines two or more numerically indexed tables into one
  77 function combine(...)
  78         local result = {}
  79         for i, a in ipairs(arg) do
  80                 for j, v in ipairs(a) do
  81                         table.insert(result, v)
  82                 end
  83         end
  84         return result
  85 end
  86
  87
  88 -- Checks whether a table has an object "value" in it
  89 function contains(table, value)
  90         for k,v in pairs(table) do
  91                 if value == v then
  92                         return true
  93                 end
  94         end
  95         return false
  96 end
  97
  98
  99 -- Dumps and strips a Lua-Function
 100 function dump(f)
 101         local d = string.dump(f)
 102         return d and strip_bytecode(d)
 103 end
 104
 105
 106 -- Dumps a table to stdout (useful for testing and debugging)
 107 function dumptable(t, i)
 108         i = i or 0
 109         for k,v in pairs(t) do
 110                 print(string.rep("\t", i) .. k, v)
 111                 if type(v) == "table" then
 112                         dumptable(v, i+1)
 113                 end
 114         end
 115 end
 116
 117
 118 -- Escapes all occurences of c in s
 119 function escape(s, c)
 120         c = c or "\\"
 121         return s:gsub(c, "\\" .. c)
 122 end
 123
 124
 125 -- Populate obj in the scope of f as key
 126 function extfenv(f, key, obj)
 127         local scope = getfenv(f)
 128         scope[key] = obj
 129 end
 130
 131
 132 -- Checks whether an object is an instanceof class
 133 function instanceof(object, class)
 134         local meta = getmetatable(object)
 135     while meta and meta.__index do
 136         if meta.__index == class then
 137                 return true
 138         end
 139         meta = getmetatable(meta.__index)
 140     end
 141     return false
 142 end
 143
 144
 145 -- Creates valid XML PCDATA from a string
 146 function pcdata(value)
 147         value = value:gsub("&", "&amp;")
 148         value = value:gsub('"', "&quot;")
 149         value = value:gsub("'", "&apos;")
 150         value = value:gsub("<", "&lt;")
 151         return value:gsub(">", "&gt;")
 152 end
 153
 154
 155 -- Resets the scope of f doing a shallow copy of its scope into a new table
 156 function resfenv(f)
 157         setfenv(f, clone(getfenv(f)))
 158 end
 159
 160
 161 -- Splits a string into an array
 162 function split(str, pat, max, regex)
 163         pat = pat or "\n"
 164         max = max or #str
 165
 166         local t = {}
 167         local c = 1
 168
 169         if #str == 0 then
 170                 return {""}
 171         end
 172
 173         if #pat == 0 then
 174                 return nil
 175         end
 176
 177         if max == 0 then
 178                 return str
 179         end
 180
 181         repeat
 182                 local s, e = str:find(pat, c, not regex)
 183                 table.insert(t, str:sub(c, s and s - 1))
 184                 max = max - 1
 185                 c = e and e + 1 or #str + 1
 186         until not s or max < 0
 187
 188         return t
 189 end
 190
 191
 192 -- Bytecode stripping function by Peter Cawley from http://lua-users.org/lists/lua-l/2008-02/msg01158.html
 193 function strip_bytecode(dump)
 194         local version, format, endian, int, size, ins, num = dump:byte(5, 11)
 195         local subint
 196         if endian == 1 then
 197                 subint = function(dump, i, l)
 198                         local val = 0
 199                         for n = l, 1, -1 do
 200                                 val = val * 256 + dump:byte(i + n - 1)
 201                         end
 202                         return val, i + l
 203                 end
 204         else
 205         subint = function(dump, i, l)
 206                 local val = 0
 207             for n = 1, l, 1 do
 208                 val = val * 256 + dump:byte(i + n - 1)
 209             end
 210             return val, i + l
 211         end
 212     end
 213
 214         local strip_function
 215         strip_function = function(dump)
 216                 local count, offset = subint(dump, 1, size)
 217                 local stripped, dirty = string.rep("\0", size), offset + count
 218                 offset = offset + count + int * 2 + 4
 219                 offset = offset + int + subint(dump, offset, int) * ins
 220                 count, offset = subint(dump, offset, int)
 221                 for n = 1, count do
 222                         local t
 223                         t, offset = subint(dump, offset, 1)
 224                         if t == 1 then
 225                                 offset = offset + 1
 226                         elseif t == 4 then
 227                                 offset = offset + size + subint(dump, offset, size)
 228                         elseif t == 3 then
 229                                 offset = offset + num
 230                         end
 231                 end
 232                 count, offset = subint(dump, offset, int)
 233                 stripped = stripped .. dump:sub(dirty, offset - 1)
 234                 for n = 1, count do
 235                         local proto, off = strip_function(dump:sub(offset, -1))
 236                         stripped, offset = stripped .. proto, offset + off - 1
 237                 end
 238                 offset = offset + subint(dump, offset, int) * int + int
 239                 count, offset = subint(dump, offset, int)
 240                 for n = 1, count do
 241                         offset = offset + subint(dump, offset, size) + size + int * 2
 242                 end
 243                 count, offset = subint(dump, offset, int)
 244                 for n = 1, count do
 245                         offset = offset + subint(dump, offset, size) + size
 246                 end
 247                 stripped = stripped .. string.rep("\0", int * 3)
 248                 return stripped, offset
 249         end
 250
 251         return dump:sub(1,12) .. strip_function(dump:sub(13,-1))
 252 end
 253
 254
 255 -- Removes whitespace from beginning and end of a string
 256 function trim(str)
 257         local s = str:gsub("^%s*(.-)%s*$", "%1")
 258         return s
 259 end
 260
 261
 262 -- Updates given table with new values
 263 function update(t, updates)
 264         for k, v in pairs(updates) do
 265                 t[k] = v
 266         end
 267 end
 268
 269
 270 -- Updates the scope of f with "extscope"
 271 function updfenv(f, extscope)
 272         update(getfenv(f), extscope)
 273 end
 274
 275
 276 -- Validates a variable
 277 function validate(value, cast_number, cast_int)
 278         if cast_number or cast_int then
 279                 value = tonumber(value)
 280         end
 281
 282         if cast_int and value and not(value % 1 == 0) then
 283                 value = nil
 284         end
 285
 286         return value
 287 end