git-annex/Locations.hs
2010-10-15 16:09:30 -04:00

55 lines
1.7 KiB
Haskell

{- git-annex file locations
-}
module Locations (
gitStateDir,
stateLoc,
keyFile,
fileKey,
annexLocation,
annexLocationRelative
) where
import Data.String.Utils
import Types
import qualified BackendTypes as Backend
import qualified GitRepo as Git
{- Long-term, cross-repo state is stored in files inside the .git-annex
- directory, in the git repository's working tree. -}
stateLoc = ".git-annex"
gitStateDir :: Git.Repo -> FilePath
gitStateDir repo = (Git.workTree repo) ++ "/" ++ stateLoc ++ "/"
{- An annexed file's content is stored in
- /path/to/repo/.git/annex/<key>, where <key> is of the form
- <backend:fragment>
-
- That allows deriving the key and backend by looking at the symlink to it.
-}
annexLocation :: Git.Repo -> Key -> FilePath
annexLocation r key =
(Git.workTree r) ++ "/" ++ (annexLocationRelative r key)
{- Annexed file's location relative to git's working tree. -}
annexLocationRelative :: Git.Repo -> Key -> FilePath
annexLocationRelative r key = Git.dir r ++ "/annex/" ++ (keyFile key)
{- Converts a key into a filename fragment.
-
- Escape "/" in the key name, to keep a flat tree of files and avoid
- issues with keys containing "/../" or ending with "/" etc.
-
- "/" is escaped to "%" because it's short and rarely used, and resembles
- a slash
- "%" is escaped to "&s", and "&" to "&a"; this ensures that the mapping
- is one to one.
- -}
keyFile :: Key -> FilePath
keyFile key = replace "/" "%" $ replace "%" "&s" $ replace "&" "&a" $ show key
{- Reverses keyFile, converting a filename fragment (ie, the basename of
- the symlink target) into a key. -}
fileKey :: FilePath -> Key
fileKey file = read $
replace "&a" "&" $ replace "&s" "%" $ replace "%" "/" file