git-annex/Annex.hs
2010-10-12 02:40:09 -04:00

101 lines
2.7 KiB
Haskell

{- git-annex toplevel code
-}
module Annex (
State,
startAnnex,
annexFile,
unannexFile
) where
import System.Posix.Files
import System.Directory
import GitRepo
import Utility
import Locations
import Backend
import BackendList
import LocationLog
-- git-annex's runtime state
data State = State {
repo :: GitRepo,
backends :: [Backend]
}
{- An annexed file's content is stored somewhere under .git/annex/ -}
annexDir :: GitRepo -> Key -> FilePath
annexDir repo key = gitDir repo ++ "/annex/" ++ key
{- On startup, examine the git repo, prepare it, and record state for
- later. -}
startAnnex :: IO State
startAnnex = do
r <- gitRepoFromCwd
gitPrep r
return State {
repo = r,
backends = parseBackendList $ gitConfig r "annex.backends" ""
}
{- Annexes a file, storing it in a backend, and then moving it into
- the annex directory and setting up the symlink pointing to its content. -}
annexFile :: State -> FilePath -> IO ()
annexFile state file = do
alreadyannexed <- lookupBackend (backends state) (repo state) file
case (alreadyannexed) of
Just _ -> error $ "already annexed: " ++ file
Nothing -> do
checkLegal file
stored <- storeFile (backends state) (repo state) file
case (stored) of
Nothing -> error $ "no backend could store: " ++ file
Just key -> symlink key
where
symlink key = do
let dest = annexDir (repo state) key
createDirectoryIfMissing True (parentDir dest)
renameFile file dest
createSymbolicLink dest file
gitAdd (repo state) file
checkLegal file = do
s <- getSymbolicLinkStatus file
if ((isSymbolicLink s) || (not $ isRegularFile s))
then error $ "not a regular file: " ++ file
else return ()
{- Inverse of annexFile. -}
unannexFile :: State -> FilePath -> IO ()
unannexFile state file = do
alreadyannexed <- lookupBackend (backends state) (repo state) file
case (alreadyannexed) of
Nothing -> error $ "not annexed " ++ file
Just _ -> do
mkey <- dropFile (backends state) (repo state) file
case (mkey) of
Nothing -> return ()
Just key -> do
let src = annexDir (repo state) key
removeFile file
renameFile src file
return ()
{- Sets up a git repo for git-annex. May be called repeatedly. -}
gitPrep :: GitRepo -> IO ()
gitPrep repo = do
-- configure git to use union merge driver on state files
let attrLine = stateLoc ++ "/*.log merge=union"
let attributes = gitAttributes repo
exists <- doesFileExist attributes
if (not exists)
then do
writeFile attributes $ attrLine ++ "\n"
gitAdd repo attributes
else do
content <- readFile attributes
if (all (/= attrLine) (lines content))
then do
appendFile attributes $ attrLine ++ "\n"
gitAdd repo attributes
else return ()