git-annex/Annex/Content/Direct.hs
2013-03-16 17:04:48 -04:00

203 lines
6.7 KiB
Haskell

{- git-annex file content managing for direct mode
-
- Copyright 2012-2013 Joey Hess <joey@kitenet.net>
-
- Licensed under the GNU GPL version 3 or higher.
-}
module Annex.Content.Direct (
associatedFiles,
removeAssociatedFile,
addAssociatedFile,
goodContent,
recordedInodeCache,
updateInodeCache,
writeInodeCache,
compareInodeCaches,
compareInodeCachesWith,
sameInodeCache,
sameFileStatus,
removeInodeCache,
toInodeCache,
inodesChanged,
createInodeSentinalFile,
) where
import Common.Annex
import qualified Annex
import Annex.Perms
import qualified Git
import Utility.TempFile
import Logs.Location
import Utility.InodeCache
{- Absolute FilePaths of Files in the tree that are associated with a key. -}
associatedFiles :: Key -> Annex [FilePath]
associatedFiles key = do
files <- associatedFilesRelative key
top <- fromRepo Git.repoPath
return $ map (top </>) files
{- List of files in the tree that are associated with a key, relative to
- the top of the repo. -}
associatedFilesRelative :: Key -> Annex [FilePath]
associatedFilesRelative key = do
mapping <- inRepo $ gitAnnexMapping key
liftIO $ catchDefaultIO [] $ do
h <- openFile mapping ReadMode
fileEncoding h
lines <$> hGetContents h
{- Changes the associated files information for a key, applying a
- transformation to the list. Returns new associatedFiles value. -}
changeAssociatedFiles :: Key -> ([FilePath] -> [FilePath]) -> Annex [FilePath]
changeAssociatedFiles key transform = do
mapping <- inRepo $ gitAnnexMapping key
files <- associatedFilesRelative key
let files' = transform files
when (files /= files') $ do
createContentDir mapping
liftIO $ viaTmp write mapping $ unlines files'
top <- fromRepo Git.repoPath
return $ map (top </>) files'
where
write file content = do
h <- openFile file WriteMode
fileEncoding h
hPutStr h content
hClose h
{- Removes an associated file. Returns new associatedFiles value. -}
removeAssociatedFile :: Key -> FilePath -> Annex [FilePath]
removeAssociatedFile key file = do
file' <- normaliseAssociatedFile file
fs <- changeAssociatedFiles key $ filter (/= file')
when (null fs) $
logStatus key InfoMissing
return fs
{- Adds an associated file. Returns new associatedFiles value. -}
addAssociatedFile :: Key -> FilePath -> Annex [FilePath]
addAssociatedFile key file = do
file' <- normaliseAssociatedFile file
changeAssociatedFiles key $ \files ->
if file' `elem` files
then files
else file':files
{- Associated files are always stored relative to the top of the repository.
- The input FilePath is relative to the CWD. -}
normaliseAssociatedFile :: FilePath -> Annex FilePath
normaliseAssociatedFile file = do
top <- fromRepo Git.repoPath
liftIO $ relPathDirToFile top <$> absPath file
{- Checks if a file in the tree, associated with a key, has not been modified.
-
- To avoid needing to fsck the file's content, which can involve an
- expensive checksum, this relies on a cache that contains the file's
- expected mtime and inode.
-}
goodContent :: Key -> FilePath -> Annex Bool
goodContent key file = sameInodeCache file =<< recordedInodeCache key
{- Gets the recorded inode cache for a key. -}
recordedInodeCache :: Key -> Annex (Maybe InodeCache)
recordedInodeCache key = withInodeCacheFile key $ \f ->
liftIO $ catchDefaultIO Nothing $ readInodeCache <$> readFile f
{- Stores a cache of attributes for a file that is associated with a key. -}
updateInodeCache :: Key -> FilePath -> Annex ()
updateInodeCache key file = maybe noop (writeInodeCache key)
=<< liftIO (genInodeCache file)
{- Writes a cache for a key. -}
writeInodeCache :: Key -> InodeCache -> Annex ()
writeInodeCache key cache = withInodeCacheFile key $ \f -> do
createContentDir f
liftIO $ writeFile f $ showInodeCache cache
{- Removes an inode cache. -}
removeInodeCache :: Key -> Annex ()
removeInodeCache key = withInodeCacheFile key $ \f -> do
createContentDir f -- also thaws directory
liftIO $ nukeFile f
withInodeCacheFile :: Key -> (FilePath -> Annex a) -> Annex a
withInodeCacheFile key a = a =<< inRepo (gitAnnexInodeCache key)
{- Checks if a InodeCache matches the current version of a file. -}
sameInodeCache :: FilePath -> Maybe InodeCache -> Annex Bool
sameInodeCache _ Nothing = return False
sameInodeCache file (Just old) = go =<< liftIO (genInodeCache file)
where
go Nothing = return False
go (Just curr) = compareInodeCaches curr old
{- Checks if a FileStatus matches the recorded InodeCache of a file. -}
sameFileStatus :: Key -> FileStatus -> Annex Bool
sameFileStatus key status = do
old <- recordedInodeCache key
let curr = toInodeCache status
r <- case (old, curr) of
(Just o, Just c) -> compareInodeCaches o c
(Nothing, Nothing) -> return True
_ -> return False
return r
{- If the inodes have changed, only the size and mtime are compared. -}
compareInodeCaches :: InodeCache -> InodeCache -> Annex Bool
compareInodeCaches x y
| compareStrong x y = return True
| otherwise = ifM inodesChanged
( return $ compareWeak x y
, return False
)
compareInodeCachesWith :: Annex InodeComparisonType
compareInodeCachesWith = ifM inodesChanged ( return Weakly, return Strongly )
{- Some filesystems get new inodes each time they are mounted.
- In order to work on such a filesystem, a sentinal file is used to detect
- when the inodes have changed.
-
- If the sentinal file does not exist, we have to assume that the
- inodes have changed.
-}
inodesChanged :: Annex Bool
inodesChanged = maybe calc return =<< Annex.getState Annex.inodeschanged
where
calc = do
scache <- liftIO . genInodeCache
=<< fromRepo gitAnnexInodeSentinal
scached <- readInodeSentinalFile
let changed = case (scache, scached) of
(Just c1, Just c2) -> not $ compareStrong c1 c2
_ -> True
Annex.changeState $ \s -> s { Annex.inodeschanged = Just changed }
return changed
readInodeSentinalFile :: Annex (Maybe InodeCache)
readInodeSentinalFile = do
sentinalcachefile <- fromRepo gitAnnexInodeSentinalCache
liftIO $ catchDefaultIO Nothing $
readInodeCache <$> readFile sentinalcachefile
writeInodeSentinalFile :: Annex ()
writeInodeSentinalFile = do
sentinalfile <- fromRepo gitAnnexInodeSentinal
sentinalcachefile <- fromRepo gitAnnexInodeSentinalCache
liftIO $ writeFile sentinalfile ""
liftIO $ maybe noop (writeFile sentinalcachefile . showInodeCache)
=<< genInodeCache sentinalfile
{- The sentinal file is only created when first initializing a repository.
- If there are any annexed objects in the repository already, creating
- the file would invalidate their inode caches. -}
createInodeSentinalFile :: Annex ()
createInodeSentinalFile =
unlessM (alreadyexists <||> hasobjects)
writeInodeSentinalFile
where
alreadyexists = isJust <$> readInodeSentinalFile
hasobjects = liftIO . doesDirectoryExist =<< fromRepo gitAnnexObjectDir