1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
|
{- git-annex Key data type
-
- Most things should not need this, using Types instead
-
- Copyright 2011 Joey Hess <joey@kitenet.net>
-
- Licensed under the GNU GPL version 3 or higher.
-}
module Types.Key (
Key(..),
AssociatedFile,
stubKey,
key2file,
file2key,
prop_idempotent_key_encode
) where
import System.Posix.Types
import Common
import Utility.QuickCheck
{- A Key has a unique name, which is derived from a particular backend,
- and may contain other optional metadata. -}
data Key = Key {
keyName :: String,
keyBackendName :: String,
keySize :: Maybe Integer,
keyMtime :: Maybe EpochTime
} deriving (Eq, Ord, Read, Show)
{- A filename may be associated with a Key. -}
type AssociatedFile = Maybe FilePath
stubKey :: Key
stubKey = Key {
keyName = "",
keyBackendName = "",
keySize = Nothing,
keyMtime = Nothing
}
fieldSep :: Char
fieldSep = '-'
{- Converts a key to a string that is suitable for use as a filename.
- The name field is always shown last, separated by doubled fieldSeps,
- and is the only field allowed to contain the fieldSep. -}
key2file :: Key -> FilePath
key2file Key { keyBackendName = b, keySize = s, keyMtime = m, keyName = n } =
b +++ ('s' ?: s) +++ ('m' ?: m) +++ (fieldSep : n)
where
"" +++ y = y
x +++ "" = x
x +++ y = x ++ fieldSep:y
c ?: (Just v) = c : show v
_ ?: _ = ""
file2key :: FilePath -> Maybe Key
file2key s = if key == Just stubKey then Nothing else key
where
key = startbackend stubKey s
startbackend k v = sepfield k v addbackend
sepfield k v a = case span (/= fieldSep) v of
(v', _:r) -> findfields r $ a k v'
_ -> Nothing
findfields (c:v) (Just k)
| c == fieldSep = Just $ k { keyName = v }
| otherwise = sepfield k v $ addfield c
findfields _ v = v
addbackend k v = Just k { keyBackendName = v }
addfield 's' k v = Just k { keySize = readish v }
addfield 'm' k v = Just k { keyMtime = readish v }
addfield _ _ _ = Nothing
instance Arbitrary Key where
arbitrary = Key
<$> arbitrary
<*> (listOf1 $ elements ['A'..'Z']) -- BACKEND
<*> ((abs <$>) <$> arbitrary) -- size cannot be negative
<*> arbitrary
prop_idempotent_key_encode :: Key -> Bool
prop_idempotent_key_encode k = Just k == (file2key . key2file) k
|