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
|
{- git-annex backend data types
-
- Mostly only backend implementations should need to import this.
-}
module BackendTypes where
import Control.Monad.State (StateT)
import Data.String.Utils
import qualified GitRepo as Git
-- command-line flags
data Flag = Force | NeedCommit
deriving (Eq, Read, Show)
-- git-annex's runtime state type doesn't really belong here,
-- but it uses Backend, so has to be here to avoid a depends loop.
data AnnexState = AnnexState {
repo :: Git.Repo,
backends :: [Backend],
flags :: [Flag]
} deriving (Show)
-- git-annex's monad
type Annex = StateT AnnexState IO
-- annexed filenames are mapped through a backend into keys
type KeyFrag = String
type BackendName = String
data Key = Key (BackendName, KeyFrag) deriving (Eq)
-- show a key to convert it to a string; the string includes the
-- name of the backend to avoid collisions between key strings
instance Show Key where
show (Key (b, k)) = b ++ ":" ++ k
instance Read Key where
readsPrec _ s = [((Key (b,k)) ,"")]
where
l = split ":" s
b = l !! 0
k = join ":" $ drop 1 l
-- pulls the backend name out
backendName :: Key -> BackendName
backendName (Key (b,k)) = b
-- pulls the key fragment out
keyFrag :: Key -> KeyFrag
keyFrag (Key (b,k)) = k
-- this structure represents a key/value backend
data Backend = Backend {
-- name of this backend
name :: String,
-- converts a filename to a key
getKey :: FilePath -> Annex (Maybe Key),
-- stores a file's contents to a key
storeFileKey :: FilePath -> Key -> Annex Bool,
-- retrieves a key's contents to a file
retrieveKeyFile :: Key -> FilePath -> Annex Bool,
-- removes a key
removeKey :: Key -> Annex Bool,
-- checks if a backend is storing the content of a key
hasKey :: Key -> Annex Bool
}
instance Show Backend where
show backend = "Backend { name =\"" ++ (name backend) ++ "\" }"
|
