85092f065ce75e46fa5b855ec15d4c3b79946afc
[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 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 -- Runs "command" and returns its output
107 function exec(command)
108 local pp = io.popen(command)
109 local data = pp:read("*a")
110 pp:close()
111
112 return data
113 end
114
115
116 -- Runs "command" and returns its output as a array of lines
117 function execl(command)
118 local pp = io.popen(command)
119 local line = ""
120 local data = {}
121
122 while true do
123 line = pp:read()
124 if (line == nil) then break end
125 table.insert(data, line)
126 end
127 pp:close()
128
129 return data
130 end
131
132
133 -- Populate obj in the scope of f as key
134 function extfenv(f, key, obj)
135 local scope = getfenv(f)
136 scope[key] = obj
137 end
138
139
140 -- Checks whether an object is an instanceof class
141 function instanceof(object, class)
142 local meta = getmetatable(object)
143 while meta and meta.__index do
144 if meta.__index == class then
145 return true
146 end
147 meta = getmetatable(meta.__index)
148 end
149 return false
150 end
151
152
153 -- Resets the scope of f doing a shallow copy of its scope into a new table
154 function resfenv(f)
155 setfenv(f, clone(getfenv(f)))
156 end
157
158
159 -- Returns the Haserl unique sessionid
160 function sessionid()
161 return ENV.SESSIONID
162 end
163
164
165 -- Splits a string into an array (Taken from lua-users.org)
166 function split(str, pat)
167 pat = pat or "\n"
168
169 local t = {}
170 local fpat = "(.-)" .. pat
171 local last_end = 1
172 local s, e, cap = str:find(fpat, 1)
173
174 while s do
175 if s ~= 1 or cap ~= "" then
176 table.insert(t,cap)
177 end
178 last_end = e+1
179 s, e, cap = str:find(fpat, last_end)
180 end
181
182 if last_end <= #str then
183 cap = str:sub(last_end)
184 table.insert(t, cap)
185 end
186
187 return t
188 end
189
190
191 -- Updates given table with new values
192 function update(t, updates)
193 for k, v in pairs(updates) do
194 t[k] = v
195 end
196 end
197
198
199 -- Updates the scope of f with "extscope"
200 function updfenv(f, extscope)
201 update(getfenv(f), extscope)
202 end
203
204
205 -- Validates a variable
206 function validate(value, cast_number, cast_int)
207 if cast_number or cast_int then
208 value = tonumber(value)
209 end
210
211 if cast_int and value and not(value % 1 == 0) then
212 value = nil
213 end
214
215 return value
216 end
217
218
219 -- Returns the filename of the calling script
220 function __file__()
221 return debug.getinfo(2, 'S').source:sub(2)
222 end