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 -- Checks whether a table has an object "value" in it
  60 function contains(table, value)
  61         for k,v in pairs(table) do
  62                 if value == v then
  63                         return true
  64                 end
  65         end
  66         return false
  67 end
  68
  69
  70 -- Dumps a table to stdout (useful for testing and debugging)
  71 function dumptable(t, i)
  72         i = i or 0
  73         for k,v in pairs(t) do
  74                 print(string.rep("\t", i) .. k, v)
  75                 if type(v) == "table" then
  76                         dumptable(v, i+1)
  77                 end
  78         end
  79 end
  80
  81
  82 -- Escapes all occurences of c in s
  83 function escape(s, c)
  84         c = c or "\\"
  85         return s:gsub(c, "\\" .. c)
  86 end
  87
  88
  89 -- Runs "command" and returns its output
  90 function exec(command)
  91         local pp   = io.popen(command)
  92         local data = pp:read("*a")
  93         pp:close()
  94
  95         return data
  96 end
  97
  98
  99 -- Runs "command" and returns its output as a array of lines
 100 function execl(command)
 101         local pp   = io.popen(command)
 102         local line = ""
 103         local data = {}
 104
 105         while true do
 106                 line = pp:read()
 107                 if (line == nil) then break end
 108                 table.insert(data, line)
 109         end
 110         pp:close()
 111
 112         return data
 113 end
 114
 115
 116 -- Populate obj in the scope of f as key
 117 function extfenv(f, key, obj)
 118         local scope = getfenv(f)
 119         scope[key] = obj
 120 end
 121
 122
 123 -- Checks whether an object is an instanceof class
 124 function instanceof(object, class)
 125         local meta = getmetatable(object)
 126     while meta and meta.__index do
 127         if meta.__index == class then
 128                 return true
 129         end
 130         meta = getmetatable(meta.__index)
 131     end
 132     return false
 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         local scope = getfenv(f)
 139         setfenv(f, {})
 140         updfenv(f, scope)
 141 end
 142
 143
 144 -- Returns the Haserl unique sessionid
 145 function sessionid()
 146         return ENV.SESSIONID
 147 end
 148
 149 -- Updates the scope of f with "extscope"
 150 function updfenv(f, extscope)
 151         local scope = getfenv(f)
 152         for k, v in pairs(extscope) do
 153                 scope[k] = v
 154         end
 155 end
 156
 157
 158 -- Validates a variable
 159 function validate(value, valid, cast_number, cast_int)
 160         if cast_number or cast_int then
 161                 value = tonumber(value)
 162         end
 163
 164         if cast_int and value and not(value % 1 == 0) then
 165                 value = nil
 166         end
 167
 168
 169         if type(valid) == "function" then
 170                 value = valid(value)
 171         elseif type(valid) == "table" then
 172                 if not contains(valid, value) then
 173                         value = nil
 174                 end
 175         end
 176
 177         return value
 178 end
 179
 180
 181 -- Returns the filename of the calling script
 182 function __file__()
 183         return debug.getinfo(2, 'S').source:sub(2)
 184 end