git-annex/Content.hs

276 lines
8.4 KiB
Haskell

{- git-annex file content managing
-
- Copyright 2010 Joey Hess <joey@kitenet.net>
-
- Licensed under the GNU GPL version 3 or higher.
-}
module Content (
inAnnex,
calcGitLink,
logStatus,
logStatusFor,
getViaTmp,
getViaTmpUnchecked,
withTmp,
checkDiskSpace,
preventWrite,
allowWrite,
moveAnnex,
removeAnnex,
fromAnnex,
moveBad,
getKeysPresent
) where
import System.IO.Error (try)
import System.Directory
import Control.Monad.State (liftIO)
import System.Path
import Control.Monad (when, unless, filterM)
import System.Posix.Files
import System.FilePath
import Data.Maybe
import Types
import Locations
import LocationLog
import UUID
import qualified GitRepo as Git
import qualified Annex
import qualified AnnexQueue
import Utility
import StatFS
import Types.Key
import DataUnits
import Config
{- Checks if a given key is currently present in the gitAnnexLocation. -}
inAnnex :: Key -> Annex Bool
inAnnex key = do
g <- Annex.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 <- Annex.gitRepo
cwd <- liftIO $ getCurrentDirectory
let absfile = maybe whoops id $ absNormPath cwd file
return $ relPathDirToFile (parentDir absfile)
(Git.workTree g) </> ".git" </> annexLocation key
where
whoops = error $ "unable to normalize " ++ file
{- Updates the LocationLog when a key's presence changes in the current
- repository.
-
- Note that the LocationLog is not updated in bare repositories.
- Operations that change a bare repository should be done from
- a non-bare repository, and the LocationLog in that repository be
- updated instead. -}
logStatus :: Key -> LogStatus -> Annex ()
logStatus key status = do
u <- getUUID =<< Annex.gitRepo
logStatusFor u key status
{- Updates the LocationLog when a key's presence changes in a repository
- identified by UUID. -}
logStatusFor :: UUID -> Key -> LogStatus -> Annex ()
logStatusFor u key status = do
g <- Annex.gitRepo
unless (Git.repoIsLocalBare g) $ do
logfile <- liftIO $ logChange g key u status
rellogfile <- liftIO $ Git.workTreeFile g logfile
AnnexQueue.add "add" [Param "--"] rellogfile
{- 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 <- Annex.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
{- 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
g <- Annex.gitRepo
let tmp = gitAnnexTmpLocation g key
liftIO $ createDirectoryIfMissing True (parentDir tmp)
success <- action tmp
if success
then do
moveAnnex key tmp
logStatus key ValuePresent
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
g <- Annex.gitRepo
let tmp = gitAnnexTmpLocation g key
liftIO $ createDirectoryIfMissing True (parentDir tmp)
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 <- Annex.gitRepo
r <- getConfig g "diskreserve" ""
let reserve = maybe megabyte id $ readSize dataUnits r
stats <- liftIO $ getFileSystemStats (gitAnnexDir g)
case (stats, keySize key) of
(Nothing, _) -> return ()
(_, Nothing) -> return ()
(Just (FileSystemStats { fsStatBytesAvailable = have }), Just need) ->
if (need + reserve > have + adjustment)
then needmorespace (need + reserve - have - adjustment)
else return ()
where
megabyte :: Integer
megabyte = 1000000
needmorespace n = do
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)"
{- Removes the write bits from a file. -}
preventWrite :: FilePath -> IO ()
preventWrite f = unsetFileMode f writebits
where
writebits = foldl unionFileModes ownerWriteMode
[groupWriteMode, otherWriteMode]
{- Turns a file's write bit back on. -}
allowWrite :: FilePath -> IO ()
allowWrite f = do
s <- getFileStatus f
setFileMode f $ fileMode s `unionFileModes` ownerWriteMode
{- 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 <- Annex.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
{- Removes a key's file from .git/annex/objects/ -}
removeAnnex :: Key -> Annex ()
removeAnnex key = do
g <- Annex.gitRepo
let file = gitAnnexLocation g key
let dir = parentDir 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 = do
g <- Annex.gitRepo
let file = gitAnnexLocation g key
let dir = parentDir 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 <- Annex.gitRepo
let src = gitAnnexLocation g key
let dest = gitAnnexBadDir g </> takeFileName src
liftIO $ createDirectoryIfMissing True (parentDir dest)
liftIO $ allowWrite (parentDir src)
liftIO $ renameFile src dest
liftIO $ removeDirectory (parentDir src)
logStatus key ValueMissing
return dest
{- List of keys whose content exists in .git/annex/objects/ -}
getKeysPresent :: Annex [Key]
getKeysPresent = do
g <- Annex.gitRepo
getKeysPresent' $ gitAnnexObjectDir g
getKeysPresent' :: FilePath -> Annex [Key]
getKeysPresent' dir = do
exists <- liftIO $ doesDirectoryExist dir
if (not exists)
then return []
else do
-- 2 levels of hashing
levela <- liftIO $ dirContents dir
levelb <- liftIO $ mapM dirContents levela
contents <- liftIO $ mapM dirContents (concat levelb)
files <- liftIO $ filterM present (concat contents)
return $ catMaybes $ map (fileKey . takeFileName) files
where
present d = do
result <- try $
getFileStatus $ d </> takeFileName d
case result of
Right s -> return $ isRegularFile s
Left _ -> return False