git-annex/Upgrade/V5/Direct.hs
Joey Hess 5a98f2d509
avoid creating content directory when locking content
If the content directory does not exist, then it does not make sense to
lock the content file, as it also does not exist, and so it's ok for the
lock operation to fail.

This avoids potential races where the content file exists but is then
deleted/renamed, while another process sees that it exists and goes to
lock it, resulting in a dangling lock file in an otherwise empty object
directory.

Also renamed modifyContent to modifyContentDir since it is not only
necessarily used for modifying content files, but also other files in
the content directory.

Sponsored-by: Dartmouth College's Datalad project
2022-05-16 12:34:56 -04:00

144 lines
4.5 KiB
Haskell

{- git-annex direct mode
-
- This only contains some remnants needed to convert away from direct mode.
-
- Copyright 2012-2014 Joey Hess <id@joeyh.name>
-
- Licensed under the GNU AGPL version 3 or higher.
-}
{-# LANGUAGE OverloadedStrings #-}
module Upgrade.V5.Direct (
switchHEADBack,
setIndirect,
goodContent,
associatedFiles,
removeAssociatedFiles,
removeInodeCache,
) where
import Annex.Common
import qualified Git
import qualified Git.Config
import qualified Git.Ref
import qualified Git.Branch
import Git.Types
import Config
import Annex.Perms
import Utility.InodeCache
import Annex.InodeSentinal
import qualified Utility.RawFilePath as R
setIndirect :: Annex ()
setIndirect = do
setbare
switchHEADBack
setConfig (annexConfig "direct") val
where
val = Git.Config.boolConfig False
coreworktree = ConfigKey "core.worktree"
indirectworktree = ConfigKey "core.indirect-worktree"
setbare = do
-- core.worktree is not compatable with
-- core.bare; git does not allow both to be set, so
-- unset it when enabling direct mode, caching in
-- core.indirect-worktree
moveconfig indirectworktree coreworktree
setConfig Git.Config.coreBare val
moveconfig src dest = getConfigMaybe src >>= \case
Nothing -> noop
Just wt -> do
unsetConfig src
setConfig dest (fromConfigValue wt)
reloadConfig
{- Converts a directBranch back to the original branch.
-
- Any other ref is left unchanged.
-}
fromDirectBranch :: Ref -> Ref
fromDirectBranch directhead = case splitc '/' $ fromRef directhead of
("refs":"heads":"annex":"direct":rest) ->
Ref $ encodeBS $ "refs/heads/" ++ intercalate "/" rest
_ -> directhead
switchHEADBack :: Annex ()
switchHEADBack = maybe noop switch =<< inRepo Git.Branch.currentUnsafe
where
switch currhead = do
let orighead = fromDirectBranch currhead
inRepo (Git.Ref.sha currhead) >>= \case
Just headsha
| orighead == currhead -> noop
| otherwise -> do
inRepo $ Git.Branch.update "leaving direct mode" orighead headsha
inRepo $ Git.Branch.checkout orighead
inRepo $ Git.Branch.delete currhead
Nothing -> inRepo $ Git.Branch.checkout orighead
{- Absolute FilePaths of Files in the tree that are associated with a key. -}
associatedFiles :: Key -> Annex [FilePath]
associatedFiles key = do
files <- associatedFilesRelative key
top <- fromRawFilePath <$> 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 <- fromRawFilePath <$> calcRepo (gitAnnexMapping key)
liftIO $ catchDefaultIO [] $ withFile mapping ReadMode $ \h ->
-- Read strictly to ensure the file is closed promptly
lines <$> hGetContentsStrict h
{- Removes the list of associated files. -}
removeAssociatedFiles :: Key -> Annex ()
removeAssociatedFiles key = do
mapping <- calcRepo $ gitAnnexMapping key
modifyContentDir mapping $
liftIO $ removeWhenExistsWith R.removeLink mapping
{- 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 (toRawFilePath 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 (fromRawFilePath f)
{- Removes an inode cache. -}
removeInodeCache :: Key -> Annex ()
removeInodeCache key = withInodeCacheFile key $ \f ->
modifyContentDir f $
liftIO $ removeWhenExistsWith R.removeLink f
withInodeCacheFile :: Key -> (RawFilePath -> Annex a) -> Annex a
withInodeCacheFile key a = a =<< calcRepo (gitAnnexInodeCache key)
{- File that maps from a key to the file(s) in the git repository. -}
gitAnnexMapping :: Key -> Git.Repo -> GitConfig -> IO RawFilePath
gitAnnexMapping key r c = do
loc <- gitAnnexLocation key r c
return $ loc <> ".map"
{- File that caches information about a key's content, used to determine
- if a file has changed. -}
gitAnnexInodeCache :: Key -> Git.Repo -> GitConfig -> IO RawFilePath
gitAnnexInodeCache key r c = do
loc <- gitAnnexLocation key r c
return $ loc <> ".cache"