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1 | 525bfb36 | Iustin Pop | {-| Utility functions. -} |
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2 | e4f08c46 | Iustin Pop | |
3 | e2fa2baf | Iustin Pop | {- |
4 | e2fa2baf | Iustin Pop | |
5 | 5850e990 | Iustin Pop | Copyright (C) 2009, 2010, 2011, 2012 Google Inc. |
6 | e2fa2baf | Iustin Pop | |
7 | e2fa2baf | Iustin Pop | This program is free software; you can redistribute it and/or modify |
8 | e2fa2baf | Iustin Pop | it under the terms of the GNU General Public License as published by |
9 | e2fa2baf | Iustin Pop | the Free Software Foundation; either version 2 of the License, or |
10 | e2fa2baf | Iustin Pop | (at your option) any later version. |
11 | e2fa2baf | Iustin Pop | |
12 | e2fa2baf | Iustin Pop | This program is distributed in the hope that it will be useful, but |
13 | e2fa2baf | Iustin Pop | WITHOUT ANY WARRANTY; without even the implied warranty of |
14 | e2fa2baf | Iustin Pop | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
15 | e2fa2baf | Iustin Pop | General Public License for more details. |
16 | e2fa2baf | Iustin Pop | |
17 | e2fa2baf | Iustin Pop | You should have received a copy of the GNU General Public License |
18 | e2fa2baf | Iustin Pop | along with this program; if not, write to the Free Software |
19 | e2fa2baf | Iustin Pop | Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA |
20 | e2fa2baf | Iustin Pop | 02110-1301, USA. |
21 | e2fa2baf | Iustin Pop | |
22 | e2fa2baf | Iustin Pop | -} |
23 | e2fa2baf | Iustin Pop | |
24 | 26d62e4c | Iustin Pop | module Ganeti.Utils |
25 | ebf38064 | Iustin Pop | ( debug |
26 | ebf38064 | Iustin Pop | , debugFn |
27 | ebf38064 | Iustin Pop | , debugXy |
28 | ebf38064 | Iustin Pop | , sepSplit |
29 | ebf38064 | Iustin Pop | , stdDev |
30 | ebf38064 | Iustin Pop | , if' |
31 | ebf38064 | Iustin Pop | , select |
32 | ebf38064 | Iustin Pop | , applyIf |
33 | ebf38064 | Iustin Pop | , commaJoin |
34 | 79eef90b | Agata Murawska | , ensureQuoted |
35 | ebf38064 | Iustin Pop | , tryRead |
36 | ebf38064 | Iustin Pop | , formatTable |
37 | c3024b7e | René Nussbaumer | , printTable |
38 | ebf38064 | Iustin Pop | , parseUnit |
39 | 19e310cc | René Nussbaumer | , plural |
40 | 04edfc99 | Iustin Pop | , niceSort |
41 | 04edfc99 | Iustin Pop | , niceSortKey |
42 | 88a10df5 | Iustin Pop | , exitIfBad |
43 | 88a10df5 | Iustin Pop | , exitErr |
44 | 88a10df5 | Iustin Pop | , exitWhen |
45 | 88a10df5 | Iustin Pop | , exitUnless |
46 | 256e28c4 | Iustin Pop | , rStripSpace |
47 | 80a0546b | Michele Tartara | , newUUID |
48 | ebf38064 | Iustin Pop | ) where |
49 | e4f08c46 | Iustin Pop | |
50 | 256e28c4 | Iustin Pop | import Data.Char (toUpper, isAlphaNum, isDigit, isSpace) |
51 | 04edfc99 | Iustin Pop | import Data.Function (on) |
52 | 29ac5975 | Iustin Pop | import Data.List |
53 | e4f08c46 | Iustin Pop | |
54 | e4f08c46 | Iustin Pop | import Debug.Trace |
55 | e4f08c46 | Iustin Pop | |
56 | 88a10df5 | Iustin Pop | import Ganeti.BasicTypes |
57 | 80a0546b | Michele Tartara | import qualified Ganeti.Constants as C |
58 | 88a10df5 | Iustin Pop | import System.IO |
59 | 88a10df5 | Iustin Pop | import System.Exit |
60 | 88a10df5 | Iustin Pop | |
61 | 9188aeef | Iustin Pop | -- * Debug functions |
62 | 9188aeef | Iustin Pop | |
63 | e4f08c46 | Iustin Pop | -- | To be used only for debugging, breaks referential integrity. |
64 | e4f08c46 | Iustin Pop | debug :: Show a => a -> a |
65 | e4f08c46 | Iustin Pop | debug x = trace (show x) x |
66 | e4f08c46 | Iustin Pop | |
67 | 525bfb36 | Iustin Pop | -- | Displays a modified form of the second parameter before returning |
68 | 525bfb36 | Iustin Pop | -- it. |
69 | adc5c176 | Iustin Pop | debugFn :: Show b => (a -> b) -> a -> a |
70 | adc5c176 | Iustin Pop | debugFn fn x = debug (fn x) `seq` x |
71 | adc5c176 | Iustin Pop | |
72 | 525bfb36 | Iustin Pop | -- | Show the first parameter before returning the second one. |
73 | adc5c176 | Iustin Pop | debugXy :: Show a => a -> b -> b |
74 | 05ff7a00 | Agata Murawska | debugXy = seq . debug |
75 | adc5c176 | Iustin Pop | |
76 | 525bfb36 | Iustin Pop | -- * Miscellaneous |
77 | 1b7cf8ca | Iustin Pop | |
78 | 61bbbed7 | Agata Murawska | -- | Apply the function if condition holds, otherwise use default value. |
79 | 61bbbed7 | Agata Murawska | applyIf :: Bool -> (a -> a) -> a -> a |
80 | 61bbbed7 | Agata Murawska | applyIf b f x = if b then f x else x |
81 | 61bbbed7 | Agata Murawska | |
82 | e4f08c46 | Iustin Pop | -- | Comma-join a string list. |
83 | e4f08c46 | Iustin Pop | commaJoin :: [String] -> String |
84 | e4f08c46 | Iustin Pop | commaJoin = intercalate "," |
85 | e4f08c46 | Iustin Pop | |
86 | 748d5d50 | Iustin Pop | -- | Split a list on a separator and return an array. |
87 | 748d5d50 | Iustin Pop | sepSplit :: Eq a => a -> [a] -> [[a]] |
88 | e4f08c46 | Iustin Pop | sepSplit sep s |
89 | ebf38064 | Iustin Pop | | null s = [] |
90 | ebf38064 | Iustin Pop | | null xs = [x] |
91 | ebf38064 | Iustin Pop | | null ys = [x,[]] |
92 | ebf38064 | Iustin Pop | | otherwise = x:sepSplit sep ys |
93 | ebf38064 | Iustin Pop | where (x, xs) = break (== sep) s |
94 | ebf38064 | Iustin Pop | ys = drop 1 xs |
95 | e4f08c46 | Iustin Pop | |
96 | 19e310cc | René Nussbaumer | -- | Simple pluralize helper |
97 | 19e310cc | René Nussbaumer | plural :: Int -> String -> String -> String |
98 | 19e310cc | René Nussbaumer | plural 1 s _ = s |
99 | 19e310cc | René Nussbaumer | plural _ _ p = p |
100 | 19e310cc | René Nussbaumer | |
101 | 79eef90b | Agata Murawska | -- | Ensure a value is quoted if needed. |
102 | 79eef90b | Agata Murawska | ensureQuoted :: String -> String |
103 | 79eef90b | Agata Murawska | ensureQuoted v = if not (all (\c -> isAlphaNum c || c == '.') v) |
104 | 79eef90b | Agata Murawska | then '\'':v ++ "'" |
105 | 79eef90b | Agata Murawska | else v |
106 | 79eef90b | Agata Murawska | |
107 | 9188aeef | Iustin Pop | -- * Mathematical functions |
108 | 9188aeef | Iustin Pop | |
109 | 185297fa | Iustin Pop | -- Simple and slow statistical functions, please replace with better |
110 | 185297fa | Iustin Pop | -- versions |
111 | e4f08c46 | Iustin Pop | |
112 | 525bfb36 | Iustin Pop | -- | Standard deviation function. |
113 | 4715711d | Iustin Pop | stdDev :: [Double] -> Double |
114 | 4715711d | Iustin Pop | stdDev lst = |
115 | 7570569e | Iustin Pop | -- first, calculate the list length and sum lst in a single step, |
116 | 7570569e | Iustin Pop | -- for performance reasons |
117 | 7570569e | Iustin Pop | let (ll', sx) = foldl' (\(rl, rs) e -> |
118 | 7570569e | Iustin Pop | let rl' = rl + 1 |
119 | 7570569e | Iustin Pop | rs' = rs + e |
120 | 7570569e | Iustin Pop | in rl' `seq` rs' `seq` (rl', rs')) (0::Int, 0) lst |
121 | 7570569e | Iustin Pop | ll = fromIntegral ll'::Double |
122 | 7570569e | Iustin Pop | mv = sx / ll |
123 | 7570569e | Iustin Pop | av = foldl' (\accu em -> let d = em - mv in accu + d * d) 0.0 lst |
124 | 4715711d | Iustin Pop | in sqrt (av / ll) -- stddev |
125 | dd4c56ed | Iustin Pop | |
126 | bfe6c954 | Guido Trotter | -- * Logical functions |
127 | bfe6c954 | Guido Trotter | |
128 | bfe6c954 | Guido Trotter | -- Avoid syntactic sugar and enhance readability. These functions are proposed |
129 | bfe6c954 | Guido Trotter | -- by some for inclusion in the Prelude, and at the moment they are present |
130 | bfe6c954 | Guido Trotter | -- (with various definitions) in the utility-ht package. Some rationale and |
131 | bfe6c954 | Guido Trotter | -- discussion is available at <http://www.haskell.org/haskellwiki/If-then-else> |
132 | bfe6c954 | Guido Trotter | |
133 | bfe6c954 | Guido Trotter | -- | \"if\" as a function, rather than as syntactic sugar. |
134 | bfe6c954 | Guido Trotter | if' :: Bool -- ^ condition |
135 | bfe6c954 | Guido Trotter | -> a -- ^ \"then\" result |
136 | bfe6c954 | Guido Trotter | -> a -- ^ \"else\" result |
137 | bfe6c954 | Guido Trotter | -> a -- ^ \"then\" or "else" result depending on the condition |
138 | bfe6c954 | Guido Trotter | if' True x _ = x |
139 | bfe6c954 | Guido Trotter | if' _ _ y = y |
140 | bfe6c954 | Guido Trotter | |
141 | 5b763470 | Iustin Pop | -- * Parsing utility functions |
142 | 5b763470 | Iustin Pop | |
143 | 525bfb36 | Iustin Pop | -- | Parse results from readsPrec. |
144 | 5b763470 | Iustin Pop | parseChoices :: (Monad m, Read a) => String -> String -> [(a, String)] -> m a |
145 | 5b763470 | Iustin Pop | parseChoices _ _ ((v, ""):[]) = return v |
146 | 5b763470 | Iustin Pop | parseChoices name s ((_, e):[]) = |
147 | 5b763470 | Iustin Pop | fail $ name ++ ": leftover characters when parsing '" |
148 | 5b763470 | Iustin Pop | ++ s ++ "': '" ++ e ++ "'" |
149 | 5b763470 | Iustin Pop | parseChoices name s _ = fail $ name ++ ": cannot parse string '" ++ s ++ "'" |
150 | 5b763470 | Iustin Pop | |
151 | 5b763470 | Iustin Pop | -- | Safe 'read' function returning data encapsulated in a Result. |
152 | 5b763470 | Iustin Pop | tryRead :: (Monad m, Read a) => String -> String -> m a |
153 | 5b763470 | Iustin Pop | tryRead name s = parseChoices name s $ reads s |
154 | c5f7412e | Iustin Pop | |
155 | 525bfb36 | Iustin Pop | -- | Format a table of strings to maintain consistent length. |
156 | c5f7412e | Iustin Pop | formatTable :: [[String]] -> [Bool] -> [[String]] |
157 | c5f7412e | Iustin Pop | formatTable vals numpos = |
158 | c5f7412e | Iustin Pop | let vtrans = transpose vals -- transpose, so that we work on rows |
159 | c5f7412e | Iustin Pop | -- rather than columns |
160 | c5f7412e | Iustin Pop | mlens = map (maximum . map length) vtrans |
161 | c5f7412e | Iustin Pop | expnd = map (\(flds, isnum, ml) -> |
162 | c5f7412e | Iustin Pop | map (\val -> |
163 | c5f7412e | Iustin Pop | let delta = ml - length val |
164 | c5f7412e | Iustin Pop | filler = replicate delta ' ' |
165 | c5f7412e | Iustin Pop | in if delta > 0 |
166 | c5f7412e | Iustin Pop | then if isnum |
167 | c5f7412e | Iustin Pop | then filler ++ val |
168 | c5f7412e | Iustin Pop | else val ++ filler |
169 | c5f7412e | Iustin Pop | else val |
170 | c5f7412e | Iustin Pop | ) flds |
171 | c5f7412e | Iustin Pop | ) (zip3 vtrans numpos mlens) |
172 | c5f7412e | Iustin Pop | in transpose expnd |
173 | 9b9da389 | Iustin Pop | |
174 | c3024b7e | René Nussbaumer | -- | Constructs a printable table from given header and rows |
175 | c3024b7e | René Nussbaumer | printTable :: String -> [String] -> [[String]] -> [Bool] -> String |
176 | c3024b7e | René Nussbaumer | printTable lp header rows isnum = |
177 | 2cdaf225 | Iustin Pop | unlines . map ((++) lp . (:) ' ' . unwords) $ |
178 | c3024b7e | René Nussbaumer | formatTable (header:rows) isnum |
179 | c3024b7e | René Nussbaumer | |
180 | 1cdcf8f3 | Iustin Pop | -- | Converts a unit (e.g. m or GB) into a scaling factor. |
181 | 1cdcf8f3 | Iustin Pop | parseUnitValue :: (Monad m) => String -> m Rational |
182 | 1cdcf8f3 | Iustin Pop | parseUnitValue unit |
183 | 1cdcf8f3 | Iustin Pop | -- binary conversions first |
184 | 1cdcf8f3 | Iustin Pop | | null unit = return 1 |
185 | 1cdcf8f3 | Iustin Pop | | unit == "m" || upper == "MIB" = return 1 |
186 | 1cdcf8f3 | Iustin Pop | | unit == "g" || upper == "GIB" = return kbBinary |
187 | 1cdcf8f3 | Iustin Pop | | unit == "t" || upper == "TIB" = return $ kbBinary * kbBinary |
188 | 1cdcf8f3 | Iustin Pop | -- SI conversions |
189 | 1cdcf8f3 | Iustin Pop | | unit == "M" || upper == "MB" = return mbFactor |
190 | 1cdcf8f3 | Iustin Pop | | unit == "G" || upper == "GB" = return $ mbFactor * kbDecimal |
191 | 1cdcf8f3 | Iustin Pop | | unit == "T" || upper == "TB" = return $ mbFactor * kbDecimal * kbDecimal |
192 | 1cdcf8f3 | Iustin Pop | | otherwise = fail $ "Unknown unit '" ++ unit ++ "'" |
193 | 1cdcf8f3 | Iustin Pop | where upper = map toUpper unit |
194 | 5850e990 | Iustin Pop | kbBinary = 1024 :: Rational |
195 | 5850e990 | Iustin Pop | kbDecimal = 1000 :: Rational |
196 | 1cdcf8f3 | Iustin Pop | decToBin = kbDecimal / kbBinary -- factor for 1K conversion |
197 | 1cdcf8f3 | Iustin Pop | mbFactor = decToBin * decToBin -- twice the factor for just 1K |
198 | 1cdcf8f3 | Iustin Pop | |
199 | 1cb92fac | Iustin Pop | -- | Tries to extract number and scale from the given string. |
200 | 1cb92fac | Iustin Pop | -- |
201 | 1cb92fac | Iustin Pop | -- Input must be in the format NUMBER+ SPACE* [UNIT]. If no unit is |
202 | 1cb92fac | Iustin Pop | -- specified, it defaults to MiB. Return value is always an integral |
203 | 1cb92fac | Iustin Pop | -- value in MiB. |
204 | 1cb92fac | Iustin Pop | parseUnit :: (Monad m, Integral a, Read a) => String -> m a |
205 | 1cb92fac | Iustin Pop | parseUnit str = |
206 | ebf38064 | Iustin Pop | -- TODO: enhance this by splitting the unit parsing code out and |
207 | ebf38064 | Iustin Pop | -- accepting floating-point numbers |
208 | 1cdcf8f3 | Iustin Pop | case (reads str::[(Int, String)]) of |
209 | ebf38064 | Iustin Pop | [(v, suffix)] -> |
210 | ebf38064 | Iustin Pop | let unit = dropWhile (== ' ') suffix |
211 | 1cdcf8f3 | Iustin Pop | in do |
212 | 1cdcf8f3 | Iustin Pop | scaling <- parseUnitValue unit |
213 | 1cdcf8f3 | Iustin Pop | return $ truncate (fromIntegral v * scaling) |
214 | ebf38064 | Iustin Pop | _ -> fail $ "Can't parse string '" ++ str ++ "'" |
215 | 88a10df5 | Iustin Pop | |
216 | 88a10df5 | Iustin Pop | -- | Unwraps a 'Result', exiting the program if it is a 'Bad' value, |
217 | 88a10df5 | Iustin Pop | -- otherwise returning the actual contained value. |
218 | 88a10df5 | Iustin Pop | exitIfBad :: String -> Result a -> IO a |
219 | 707cd3d7 | Helga Velroyen | exitIfBad msg (Bad s) = exitErr (msg ++ ": " ++ s) |
220 | 88a10df5 | Iustin Pop | exitIfBad _ (Ok v) = return v |
221 | 88a10df5 | Iustin Pop | |
222 | 88a10df5 | Iustin Pop | -- | Exits immediately with an error message. |
223 | 88a10df5 | Iustin Pop | exitErr :: String -> IO a |
224 | 88a10df5 | Iustin Pop | exitErr errmsg = do |
225 | 707cd3d7 | Helga Velroyen | hPutStrLn stderr $ "Error: " ++ errmsg |
226 | 88a10df5 | Iustin Pop | exitWith (ExitFailure 1) |
227 | 88a10df5 | Iustin Pop | |
228 | 88a10df5 | Iustin Pop | -- | Exits with an error message if the given boolean condition if true. |
229 | 88a10df5 | Iustin Pop | exitWhen :: Bool -> String -> IO () |
230 | 88a10df5 | Iustin Pop | exitWhen True msg = exitErr msg |
231 | 88a10df5 | Iustin Pop | exitWhen False _ = return () |
232 | 88a10df5 | Iustin Pop | |
233 | 88a10df5 | Iustin Pop | -- | Exits with an error message /unless/ the given boolean condition |
234 | 88a10df5 | Iustin Pop | -- if true, the opposite of 'exitWhen'. |
235 | 88a10df5 | Iustin Pop | exitUnless :: Bool -> String -> IO () |
236 | 88a10df5 | Iustin Pop | exitUnless cond = exitWhen (not cond) |
237 | 04edfc99 | Iustin Pop | |
238 | 04edfc99 | Iustin Pop | -- | Helper for 'niceSort'. Computes the key element for a given string. |
239 | 04edfc99 | Iustin Pop | extractKey :: [Either Integer String] -- ^ Current (partial) key, reversed |
240 | 04edfc99 | Iustin Pop | -> String -- ^ Remaining string |
241 | 04edfc99 | Iustin Pop | -> ([Either Integer String], String) |
242 | 04edfc99 | Iustin Pop | extractKey ek [] = (reverse ek, []) |
243 | 04edfc99 | Iustin Pop | extractKey ek xs@(x:_) = |
244 | 04edfc99 | Iustin Pop | let (span_fn, conv_fn) = if isDigit x |
245 | 04edfc99 | Iustin Pop | then (isDigit, Left . read) |
246 | 04edfc99 | Iustin Pop | else (not . isDigit, Right) |
247 | 04edfc99 | Iustin Pop | (k, rest) = span span_fn xs |
248 | 04edfc99 | Iustin Pop | in extractKey (conv_fn k:ek) rest |
249 | 04edfc99 | Iustin Pop | |
250 | 04edfc99 | Iustin Pop | {-| Sort a list of strings based on digit and non-digit groupings. |
251 | 04edfc99 | Iustin Pop | |
252 | 04edfc99 | Iustin Pop | Given a list of names @['a1', 'a10', 'a11', 'a2']@ this function |
253 | 04edfc99 | Iustin Pop | will sort the list in the logical order @['a1', 'a2', 'a10', 'a11']@. |
254 | 04edfc99 | Iustin Pop | |
255 | 04edfc99 | Iustin Pop | The sort algorithm breaks each name in groups of either only-digits or |
256 | 04edfc99 | Iustin Pop | no-digits, and sorts based on each group. |
257 | 04edfc99 | Iustin Pop | |
258 | 04edfc99 | Iustin Pop | Internally, this is not implemented via regexes (like the Python |
259 | 04edfc99 | Iustin Pop | version), but via actual splitting of the string in sequences of |
260 | 04edfc99 | Iustin Pop | either digits or everything else, and converting the digit sequences |
261 | 04edfc99 | Iustin Pop | in /Left Integer/ and the non-digit ones in /Right String/, at which |
262 | 04edfc99 | Iustin Pop | point sorting becomes trivial due to the built-in 'Either' ordering; |
263 | 04edfc99 | Iustin Pop | we only need one extra step of dropping the key at the end. |
264 | 04edfc99 | Iustin Pop | |
265 | 04edfc99 | Iustin Pop | -} |
266 | 04edfc99 | Iustin Pop | niceSort :: [String] -> [String] |
267 | 04edfc99 | Iustin Pop | niceSort = map snd . sort . map (\s -> (fst $ extractKey [] s, s)) |
268 | 04edfc99 | Iustin Pop | |
269 | 04edfc99 | Iustin Pop | -- | Key-version of 'niceSort'. We use 'sortBy' and @compare `on` fst@ |
270 | 04edfc99 | Iustin Pop | -- since we don't want to add an ordering constraint on the /a/ type, |
271 | 04edfc99 | Iustin Pop | -- hence the need to only compare the first element of the /(key, a)/ |
272 | 04edfc99 | Iustin Pop | -- tuple. |
273 | 04edfc99 | Iustin Pop | niceSortKey :: (a -> String) -> [a] -> [a] |
274 | 04edfc99 | Iustin Pop | niceSortKey keyfn = |
275 | 04edfc99 | Iustin Pop | map snd . sortBy (compare `on` fst) . |
276 | 04edfc99 | Iustin Pop | map (\s -> (fst . extractKey [] $ keyfn s, s)) |
277 | 256e28c4 | Iustin Pop | |
278 | 256e28c4 | Iustin Pop | -- | Strip space characthers (including newline). As this is |
279 | 256e28c4 | Iustin Pop | -- expensive, should only be run on small strings. |
280 | 256e28c4 | Iustin Pop | rStripSpace :: String -> String |
281 | 256e28c4 | Iustin Pop | rStripSpace = reverse . dropWhile isSpace . reverse |
282 | 80a0546b | Michele Tartara | |
283 | 80a0546b | Michele Tartara | -- | Returns a random UUID. |
284 | 80a0546b | Michele Tartara | -- This is a Linux-specific method as it uses the /proc filesystem. |
285 | 80a0546b | Michele Tartara | newUUID :: IO String |
286 | 80a0546b | Michele Tartara | newUUID = do |
287 | 80a0546b | Michele Tartara | contents <- readFile C.randomUuidFile |
288 | 37dfcacb | Iustin Pop | return $! rStripSpace $ take 128 contents |