core/src/ffluci/util.lua

   1 --[[
   2 FFLuCI - 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("ffluci.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 -- Checks whether a table has an object "value" in it
  77 function contains(table, value)
  78         for k,v in pairs(table) do
  79                 if value == v then
  80                         return true
  81                 end
  82         end
  83         return false
  84 end
  85
  86
  87 -- Dumps a table to stdout (useful for testing and debugging)
  88 function dumptable(t, i)
  89         i = i or 0
  90         for k,v in pairs(t) do
  91                 print(string.rep("\t", i) .. k, v)
  92                 if type(v) == "table" then
  93                         dumptable(v, i+1)
  94                 end
  95         end
  96 end
  97
  98
  99 -- Escapes all occurences of c in s
 100 function escape(s, c)
 101         c = c or "\\"
 102         return s:gsub(c, "\\" .. c)
 103 end
 104
 105
 106 -- Populate obj in the scope of f as key
 107 function extfenv(f, key, obj)
 108         local scope = getfenv(f)
 109         scope[key] = obj
 110 end
 111
 112
 113 -- Checks whether an object is an instanceof class
 114 function instanceof(object, class)
 115         local meta = getmetatable(object)
 116     while meta and meta.__index do
 117         if meta.__index == class then
 118                 return true
 119         end
 120         meta = getmetatable(meta.__index)
 121     end
 122     return false
 123 end
 124
 125
 126 -- Creates valid XML PCDATA from a string
 127 function pcdata(value)
 128         value = value:gsub("&", "&amp;")
 129         value = value:gsub('"', "&quot;")
 130         value = value:gsub("'", "&apos;")
 131         value = value:gsub("<", "&lt;")
 132         return value:gsub(">", "&gt;")
 133 end
 134
 135
 136 -- Resets the scope of f doing a shallow copy of its scope into a new table
 137 function resfenv(f)
 138         setfenv(f, clone(getfenv(f)))
 139 end
 140
 141
 142 -- Splits a string into an array
 143 function split(str, pat, max, regex)
 144         pat = pat or "\n"
 145         max = max or #str
 146
 147         local t = {}
 148         local c = 1
 149
 150         if #str == 0 then
 151                 return {""}
 152         end
 153
 154         if #pat == 0 then
 155                 return nil
 156         end
 157
 158         if max == 0 then
 159                 return str
 160         end
 161
 162         repeat
 163                 local s, e = str:find(pat, c, not regex)
 164                 table.insert(t, str:sub(c, s and s - 1))
 165                 max = max - 1
 166                 c = e and e + 1 or #str + 1
 167         until not s or max < 0
 168
 169         return t
 170 end
 171
 172 -- Removes whitespace from beginning and end of a string
 173 function trim(str)
 174         local s = str:gsub("^%s*(.-)%s*$", "%1")
 175         return s
 176 end
 177
 178 -- Updates given table with new values
 179 function update(t, updates)
 180         for k, v in pairs(updates) do
 181                 t[k] = v
 182         end
 183 end
 184
 185
 186 -- Updates the scope of f with "extscope"
 187 function updfenv(f, extscope)
 188         update(getfenv(f), extscope)
 189 end
 190
 191
 192 -- Validates a variable
 193 function validate(value, cast_number, cast_int)
 194         if cast_number or cast_int then
 195                 value = tonumber(value)
 196         end
 197
 198         if cast_int and value and not(value % 1 == 0) then
 199                 value = nil
 200         end
 201
 202         return value
 203 end