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                         inst:__init__(...)
  40                 end
  41
  42                 return inst
  43         end
  44
  45         local classmeta = {__call = create}
  46
  47         if base then
  48                 classmeta.__index = base
  49         end
  50
  51         setmetatable(class, classmeta)
  52         return class
  53 end
  54
  55
  56 -- Checks whether a table has an object "value" in it
  57 function contains(table, value)
  58         for k,v in pairs(table) do
  59                 if value == v then
  60                         return true
  61                 end
  62         end
  63         return false
  64 end
  65
  66
  67 -- Dumps a table to stdout (useful for testing and debugging)
  68 function dumptable(t, i)
  69         i = i or 0
  70         for k,v in pairs(t) do
  71                 print(string.rep("\t", i) .. k, v)
  72                 if type(v) == "table" then
  73                         dumptable(v, i+1)
  74                 end
  75         end
  76 end
  77
  78
  79 -- Escapes all occurences of c in s
  80 function escape(s, c)
  81         c = c or "\\"
  82         return s:gsub(c, "\\" .. c)
  83 end
  84
  85
  86 -- Runs "command" and returns its output
  87 function exec(command)
  88         local pp   = io.popen(command)
  89         local data = pp:read("*a")
  90         pp:close()
  91
  92         return data
  93 end
  94
  95
  96 -- Runs "command" and returns its output as a array of lines
  97 function execl(command)
  98         local pp   = io.popen(command)
  99         local line = ""
 100         local data = {}
 101
 102         while true do
 103                 line = pp:read()
 104                 if (line == nil) then break end
 105                 table.insert(data, line)
 106         end
 107         pp:close()
 108
 109         return data
 110 end
 111
 112
 113 -- Populate obj in the scope of f as key
 114 function extfenv(f, key, obj)
 115         local scope = getfenv(f)
 116         scope[key] = obj
 117         setfenv(f, scope)
 118 end
 119
 120
 121 -- Checks whether an object is an instanceof class
 122 function instanceof(object, class)
 123         local meta = getmetatable(object)
 124     while meta and meta.__index do
 125         if meta.__index == class then
 126                 return true
 127         end
 128         meta = getmetatable(meta.__index)
 129     end
 130     return false
 131 end
 132
 133
 134 -- Updates the scope of f with "extscope"
 135 function updfenv(f, extscope)
 136         local scope = getfenv(f)
 137         for k, v in pairs(extscope) do
 138                 scope[k] = v
 139         end
 140         setfenv(f, scope)
 141 end
 142
 143
 144 -- Returns the filename of the calling script
 145 function __file__()
 146         return debug.getinfo(2, 'S').source:sub(2)
 147 end