* Major repository revision
[project/luci.git] / core / 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 -- 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 -- Returns the Haserl unique sessionid
143 function sessionid()
144 return ENV.SESSIONID
145 end
146
147
148 -- Splits a string into an array (Adapted from lua-users.org)
149 function split(str, pat, max)
150 pat = pat or "\n"
151 max = max or -1
152
153 local t = {}
154 local fpat = "(.-)" .. pat
155 local last_end = 1
156 local s, e, cap = str:find(fpat, 1)
157
158 while s do
159 max = max - 1
160 if s ~= 1 or cap ~= "" then
161 table.insert(t,cap)
162 end
163 last_end = e+1
164 if max == 0 then
165 break
166 end
167 s, e, cap = str:find(fpat, last_end)
168 end
169
170 if last_end <= #str then
171 cap = str:sub(last_end)
172 table.insert(t, cap)
173 end
174
175 return t
176 end
177
178 -- Removes whitespace from beginning and end of a string
179 function trim (string)
180 return string:gsub("^%s*(.-)%s*$", "%1")
181 end
182
183 -- Updates given table with new values
184 function update(t, updates)
185 for k, v in pairs(updates) do
186 t[k] = v
187 end
188 end
189
190
191 -- Updates the scope of f with "extscope"
192 function updfenv(f, extscope)
193 update(getfenv(f), extscope)
194 end
195
196
197 -- Validates a variable
198 function validate(value, cast_number, cast_int)
199 if cast_number or cast_int then
200 value = tonumber(value)
201 end
202
203 if cast_int and value and not(value % 1 == 0) then
204 value = nil
205 end
206
207 return value
208 end