* Mördercommit ;-)
[project/luci.git] / core / src / 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