* CBI updates
[project/luci.git] / 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 end
118
119
120 -- Checks whether an object is an instanceof class
121 function instanceof(object, class)
122 local meta = getmetatable(object)
123 while meta and meta.__index do
124 if meta.__index == class then
125 return true
126 end
127 meta = getmetatable(meta.__index)
128 end
129 return false
130 end
131
132
133 -- Resets the scope of f doing a shallow copy of its scope into a new table
134 function resfenv(f)
135 local scope = getfenv(f)
136 setfenv(f, {})
137 updfenv(f, scope)
138 end
139
140
141 -- Updates the scope of f with "extscope"
142 function updfenv(f, extscope)
143 local scope = getfenv(f)
144 for k, v in pairs(extscope) do
145 scope[k] = v
146 end
147 end
148
149
150 -- Validates a variable
151 function validate(value, cast_number, cast_int, valid)
152 if cast_number or cast_int then
153 value = tonumber(value)
154 end
155
156 if cast_int and not(value % 1 == 0) then
157 value = nil
158 end
159
160
161 if type(valid) == "function" then
162 value = valid(value)
163 elseif type(valid) == "table" then
164 if not contains(valid, value) then
165 value = nil
166 end
167 end
168
169 return value
170 end
171
172
173 -- Returns the filename of the calling script
174 function __file__()
175 return debug.getinfo(2, 'S').source:sub(2)
176 end