git-annex/Annex/Content.hs
2011-10-15 17:47:03 -04:00

237 lines
7.2 KiB
Haskell

{- git-annex file content managing
-
- Copyright 2010 Joey Hess <joey@kitenet.net>
-
- Licensed under the GNU GPL version 3 or higher.
-}
module Annex.Content (
inAnnex,
calcGitLink,
logStatus,
getViaTmp,
getViaTmpUnchecked,
withTmp,
checkDiskSpace,
moveAnnex,
removeAnnex,
fromAnnex,
moveBad,
getKeysPresent,
saveState
) where
import Common.Annex
import Logs.Location
import Annex.UUID
import qualified Git
import qualified Annex
import qualified Annex.Queue
import qualified Annex.Branch
import Utility.StatFS
import Utility.FileMode
import Types.Key
import Utility.DataUnits
import Config
{- Checks if a given key is currently present in the gitAnnexLocation. -}
inAnnex :: Key -> Annex Bool
inAnnex key = do
g <- gitRepo
when (Git.repoIsUrl g) $ error "inAnnex cannot check remote repo"
liftIO $ doesFileExist $ gitAnnexLocation g key
{- Calculates the relative path to use to link a file to a key. -}
calcGitLink :: FilePath -> Key -> Annex FilePath
calcGitLink file key = do
g <- gitRepo
cwd <- liftIO getCurrentDirectory
let absfile = fromMaybe whoops $ absNormPath cwd file
return $ relPathDirToFile (parentDir absfile)
(Git.workTree g) </> ".git" </> annexLocation key
where
whoops = error $ "unable to normalize " ++ file
{- Updates the Logs.Location when a key's presence changes in the current
- repository. -}
logStatus :: Key -> LogStatus -> Annex ()
logStatus key status = do
g <- gitRepo
u <- getUUID
logChange g key u status
{- Runs an action, passing it a temporary filename to download,
- and if the action succeeds, moves the temp file into
- the annex as a key's content. -}
getViaTmp :: Key -> (FilePath -> Annex Bool) -> Annex Bool
getViaTmp key action = do
g <- gitRepo
let tmp = gitAnnexTmpLocation g key
-- Check that there is enough free disk space.
-- When the temp file already exists, count the space
-- it is using as free.
e <- liftIO $ doesFileExist tmp
if e
then do
stat <- liftIO $ getFileStatus tmp
checkDiskSpace' (fromIntegral $ fileSize stat) key
else checkDiskSpace key
when e $ liftIO $ allowWrite tmp
getViaTmpUnchecked key action
prepTmp :: Key -> Annex FilePath
prepTmp key = do
g <- gitRepo
let tmp = gitAnnexTmpLocation g key
liftIO $ createDirectoryIfMissing True (parentDir tmp)
return tmp
{- Like getViaTmp, but does not check that there is enough disk space
- for the incoming key. For use when the key content is already on disk
- and not being copied into place. -}
getViaTmpUnchecked :: Key -> (FilePath -> Annex Bool) -> Annex Bool
getViaTmpUnchecked key action = do
tmp <- prepTmp key
success <- action tmp
if success
then do
moveAnnex key tmp
logStatus key InfoPresent
return True
else do
-- the tmp file is left behind, in case caller wants
-- to resume its transfer
return False
{- Creates a temp file, runs an action on it, and cleans up the temp file. -}
withTmp :: Key -> (FilePath -> Annex a) -> Annex a
withTmp key action = do
tmp <- prepTmp key
res <- action tmp
liftIO $ whenM (doesFileExist tmp) $ liftIO $ removeFile tmp
return res
{- Checks that there is disk space available to store a given key,
- throwing an error if not. -}
checkDiskSpace :: Key -> Annex ()
checkDiskSpace = checkDiskSpace' 0
checkDiskSpace' :: Integer -> Key -> Annex ()
checkDiskSpace' adjustment key = do
g <- gitRepo
r <- getConfig g "diskreserve" ""
let reserve = fromMaybe megabyte $ readSize dataUnits r
stats <- liftIO $ getFileSystemStats (gitAnnexDir g)
case (stats, keySize key) of
(Nothing, _) -> return ()
(_, Nothing) -> return ()
(Just (FileSystemStats { fsStatBytesAvailable = have }), Just need) ->
when (need + reserve > have + adjustment) $
needmorespace (need + reserve - have - adjustment)
where
megabyte :: Integer
megabyte = 1000000
needmorespace n = unlessM (Annex.getState Annex.force) $
error $ "not enough free space, need " ++
roughSize storageUnits True n ++
" more (use --force to override this check or adjust annex.diskreserve)"
{- Moves a file into .git/annex/objects/
-
- What if the key there already has content? This could happen for
- various reasons; perhaps the same content is being annexed again.
- Perhaps there has been a hash collision generating the keys.
-
- The current strategy is to assume that in this case it's safe to delete
- one of the two copies of the content; and the one already in the annex
- is left there, assuming it's the original, canonical copy.
-
- I considered being more paranoid, and checking that both files had
- the same content. Decided against it because A) users explicitly choose
- a backend based on its hashing properties and so if they're dealing
- with colliding files it's their own fault and B) adding such a check
- would not catch all cases of colliding keys. For example, perhaps
- a remote has a key; if it's then added again with different content then
- the overall system now has two different peices of content for that
- key, and one of them will probably get deleted later. So, adding the
- check here would only raise expectations that git-annex cannot truely
- meet.
-}
moveAnnex :: Key -> FilePath -> Annex ()
moveAnnex key src = do
g <- gitRepo
let dest = gitAnnexLocation g key
let dir = parentDir dest
e <- liftIO $ doesFileExist dest
if e
then liftIO $ removeFile src
else liftIO $ do
createDirectoryIfMissing True dir
allowWrite dir -- in case the directory already exists
renameFile src dest
preventWrite dest
preventWrite dir
withObjectLoc :: Key -> ((FilePath, FilePath) -> Annex a) -> Annex a
withObjectLoc key a = do
g <- gitRepo
let file = gitAnnexLocation g key
let dir = parentDir file
a (dir, file)
{- Removes a key's file from .git/annex/objects/ -}
removeAnnex :: Key -> Annex ()
removeAnnex key = withObjectLoc key $ \(dir, file) -> liftIO $ do
allowWrite dir
removeFile file
removeDirectory dir
{- Moves a key's file out of .git/annex/objects/ -}
fromAnnex :: Key -> FilePath -> Annex ()
fromAnnex key dest = withObjectLoc key $ \(dir, file) -> liftIO $ do
allowWrite dir
allowWrite file
renameFile file dest
removeDirectory dir
{- Moves a key out of .git/annex/objects/ into .git/annex/bad, and
- returns the file it was moved to. -}
moveBad :: Key -> Annex FilePath
moveBad key = do
g <- gitRepo
let src = gitAnnexLocation g key
let dest = gitAnnexBadDir g </> takeFileName src
liftIO $ do
createDirectoryIfMissing True (parentDir dest)
allowWrite (parentDir src)
renameFile src dest
removeDirectory (parentDir src)
logStatus key InfoMissing
return dest
{- List of keys whose content exists in .git/annex/objects/ -}
getKeysPresent :: Annex [Key]
getKeysPresent = do
g <- gitRepo
getKeysPresent' $ gitAnnexObjectDir g
getKeysPresent' :: FilePath -> Annex [Key]
getKeysPresent' dir = do
exists <- liftIO $ doesDirectoryExist dir
if not exists
then return []
else liftIO $ do
-- 2 levels of hashing
levela <- dirContents dir
levelb <- mapM dirContents levela
contents <- mapM dirContents (concat levelb)
let files = concat contents
return $ mapMaybe (fileKey . takeFileName) files
{- Things to do to record changes to content. -}
saveState :: Annex ()
saveState = do
Annex.Queue.flush False
Annex.Branch.commit "update"