git-annex/Annex/Content/Direct.hs
Joey Hess 1572c460e8 avoid using openFile when withFile can be used
Potentially fixes some FD leak if an action on an opened file handle fails
for some reason. There have been some hard to reproduce reports of
git-annex leaking FDs, and this may solve them.
2014-02-03 10:19:06 -04:00

253 lines
8.4 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,
associatedFilesRelative,
removeAssociatedFile,
removeAssociatedFileUnchecked,
removeAssociatedFiles,
addAssociatedFile,
goodContent,
recordedInodeCache,
updateInodeCache,
addInodeCache,
writeInodeCache,
compareInodeCaches,
compareInodeCachesWith,
sameInodeCache,
elemInodeCaches,
sameFileStatus,
removeInodeCache,
toInodeCache,
inodesChanged,
createInodeSentinalFile,
addContentWhenNotPresent,
) where
import Common.Annex
import qualified Annex
import Annex.Perms
import qualified Git
import Utility.Tmp
import Logs.Location
import Utility.InodeCache
import Utility.CopyFile
import Annex.ReplaceFile
import Annex.Link
{- 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 <- calcRepo $ gitAnnexMapping key
liftIO $ catchDefaultIO [] $ withFile mapping ReadMode $ \h -> do
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 <- calcRepo $ gitAnnexMapping key
files <- associatedFilesRelative key
let files' = transform files
when (files /= files') $ do
modifyContent mapping $
liftIO $ viaTmp writeFileAnyEncoding mapping $
unlines files'
top <- fromRepo Git.repoPath
return $ map (top </>) files'
{- Removes the list of associated files. -}
removeAssociatedFiles :: Key -> Annex ()
removeAssociatedFiles key = do
mapping <- calcRepo $ gitAnnexMapping key
modifyContent mapping $
liftIO $ nukeFile mapping
{- Removes an associated file. Returns new associatedFiles value.
- Checks if this was the last copy of the object, and updates location
- log. -}
removeAssociatedFile :: Key -> FilePath -> Annex [FilePath]
removeAssociatedFile key file = do
fs <- removeAssociatedFileUnchecked key file
when (null fs) $
logStatus key InfoMissing
return fs
{- Removes an associated file. Returns new associatedFiles value. -}
removeAssociatedFileUnchecked :: Key -> FilePath -> Annex [FilePath]
removeAssociatedFileUnchecked key file = do
file' <- normaliseAssociatedFile file
changeAssociatedFiles key $ filter (/= file')
{- 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, or is absolute. -}
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.
-
- A key can be associated with multiple files, so may return more than
- one. -}
recordedInodeCache :: Key -> Annex [InodeCache]
recordedInodeCache key = withInodeCacheFile key $ \f ->
liftIO $ catchDefaultIO [] $
mapMaybe readInodeCache . lines <$> readFileStrict f
{- Caches an inode for a file.
-
- Anything else already cached is preserved.
-}
updateInodeCache :: Key -> FilePath -> Annex ()
updateInodeCache key file = maybe noop (addInodeCache key)
=<< liftIO (genInodeCache file)
{- Adds another inode to the cache for a key. -}
addInodeCache :: Key -> InodeCache -> Annex ()
addInodeCache key cache = do
oldcaches <- recordedInodeCache key
unlessM (elemInodeCaches cache oldcaches) $
writeInodeCache key (cache:oldcaches)
{- Writes inode cache for a key. -}
writeInodeCache :: Key -> [InodeCache] -> Annex ()
writeInodeCache key caches = withInodeCacheFile key $ \f ->
modifyContent f $
liftIO $ writeFile f $
unlines $ map showInodeCache caches
{- Removes an inode cache. -}
removeInodeCache :: Key -> Annex ()
removeInodeCache key = withInodeCacheFile key $ \f ->
modifyContent f $
liftIO $ nukeFile f
withInodeCacheFile :: Key -> (FilePath -> Annex a) -> Annex a
withInodeCacheFile key a = a =<< calcRepo (gitAnnexInodeCache key)
{- Checks if a InodeCache matches the current version of a file. -}
sameInodeCache :: FilePath -> [InodeCache] -> Annex Bool
sameInodeCache _ [] = return False
sameInodeCache file old = go =<< liftIO (genInodeCache file)
where
go Nothing = return False
go (Just curr) = elemInodeCaches 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
case (old, curr) of
(_, Just c) -> elemInodeCaches c old
([], Nothing) -> return True
_ -> return False
{- 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
)
elemInodeCaches :: InodeCache -> [InodeCache] -> Annex Bool
elemInodeCaches _ [] = return False
elemInodeCaches c (l:ls) = ifM (compareInodeCaches c l)
( return True
, elemInodeCaches c ls
)
compareInodeCachesWith :: Annex InodeComparisonType
compareInodeCachesWith = ifM inodesChanged ( return Weakly, return Strongly )
{- Copies the contentfile to the associated file, if the associated
- file has no content. If the associated file does have content,
- even if the content differs, it's left unchanged. -}
addContentWhenNotPresent :: Key -> FilePath -> FilePath -> Annex ()
addContentWhenNotPresent key contentfile associatedfile = do
v <- isAnnexLink associatedfile
when (Just key == v) $
replaceFile associatedfile $
liftIO . void . copyFileExternal contentfile
updateInodeCache key associatedfile
{- 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
createAnnexDirectory (parentDir sentinalfile)
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