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
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
|
{- git-annex key/value backends
-
- Copyright 2010 Joey Hess <joey@kitenet.net>
-
- Licensed under the GNU GPL version 3 or higher.
-}
module Backend (
list,
orderedList,
genKey,
lookupFile,
chooseBackend,
lookupBackendName,
maybeLookupBackendName
) where
import System.Posix.Files
import Common.Annex
import qualified Annex
import Annex.CheckAttr
import Annex.CatFile
import Types.Key
import Types.KeySource
import qualified Types.Backend as B
import Config
-- When adding a new backend, import it here and add it to the list.
import qualified Backend.SHA
import qualified Backend.WORM
import qualified Backend.URL
list :: [Backend]
list = Backend.SHA.backends ++ Backend.WORM.backends ++ Backend.URL.backends
{- List of backends in the order to try them when storing a new key. -}
orderedList :: Annex [Backend]
orderedList = do
l <- Annex.getState Annex.backends -- list is cached here
if not $ null l
then return l
else do
f <- Annex.getState Annex.forcebackend
case f of
Just name | not (null name) ->
return [lookupBackendName name]
_ -> do
l' <- gen . annexBackends <$> Annex.getGitConfig
Annex.changeState $ \s -> s { Annex.backends = l' }
return l'
where
gen [] = list
gen l = map lookupBackendName l
{- Generates a key for a file, trying each backend in turn until one
- accepts it. -}
genKey :: KeySource -> Maybe Backend -> Annex (Maybe (Key, Backend))
genKey source trybackend = do
bs <- orderedList
let bs' = maybe bs (: bs) trybackend
genKey' bs' source
genKey' :: [Backend] -> KeySource -> Annex (Maybe (Key, Backend))
genKey' [] _ = return Nothing
genKey' (b:bs) source = do
r <- B.getKey b source
case r of
Nothing -> genKey' bs source
Just k -> return $ Just (makesane k, b)
where
-- keyNames should not contain newline characters.
makesane k = k { keyName = map fixbadchar (keyName k) }
fixbadchar c
| c == '\n' = '_'
| otherwise = c
{- Looks up the key and backend corresponding to an annexed file,
- by examining what the file symlinks to.
-
- In direct mode, there is often no symlink on disk, in which case
- the symlink is looked up in git instead. However, a real symlink
- on disk still takes precedence over what was committed to git in direct
- mode.
-}
lookupFile :: FilePath -> Annex (Maybe (Key, Backend))
lookupFile file = do
tl <- liftIO $ tryIO $ readSymbolicLink file
case tl of
Right l
| isLinkToAnnex l -> makekey l
| otherwise -> return Nothing
Left _ -> ifM isDirect
( maybe (return Nothing) makeret =<< catKeyFile file
, return Nothing
)
where
makekey l = maybe (return Nothing) makeret (fileKey $ takeFileName l)
makeret k = let bname = keyBackendName k in
case maybeLookupBackendName bname of
Just backend -> do
return $ Just (k, backend)
Nothing -> do
warning $
"skipping " ++ file ++
" (unknown backend " ++ bname ++ ")"
return Nothing
{- Looks up the backend that should be used for a file.
- That can be configured on a per-file basis in the gitattributes file. -}
chooseBackend :: FilePath -> Annex (Maybe Backend)
chooseBackend f = Annex.getState Annex.forcebackend >>= go
where
go Nothing = maybeLookupBackendName <$> checkAttr "annex.backend" f
go (Just _) = Just . Prelude.head <$> orderedList
{- Looks up a backend by name. May fail if unknown. -}
lookupBackendName :: String -> Backend
lookupBackendName s = fromMaybe unknown $ maybeLookupBackendName s
where
unknown = error $ "unknown backend " ++ s
maybeLookupBackendName :: String -> Maybe Backend
maybeLookupBackendName s = headMaybe matches
where
matches = filter (\b -> s == B.name b) list
|
