git-annex/Logs/File.hs
Joey Hess 97fd9da6e7
add back non-preferred files to imported tree
Prevents merging the import from deleting the non-preferred files from
the branch it's merged into.

adjustTree previously appended the new list of items to the old, which
could result in it generating a tree with multiple files with the same
name. That is not good and confuses some parts of git. Gave it a
function to resolve such conflicts.

That allowed dealing with the problem of what happens when the import
contains some files (or subtrees) with the same name as files that were
filtered out of the export. The files from the import win.
2019-05-20 16:43:52 -04:00

74 lines
2.4 KiB
Haskell

{- git-annex log files
-
- Copyright 2018 Joey Hess <id@joeyh.name>
-
- Licensed under the GNU AGPL version 3 or higher.
-}
module Logs.File (writeLogFile, withLogHandle, appendLogFile, streamLogFile) where
import Annex.Common
import Annex.Perms
import Annex.LockFile
import Annex.ReplaceFile
import qualified Git
import Utility.Tmp
-- | Writes content to a file, replacing the file atomically, and
-- making the new file have whatever permissions the git repository is
-- configured to use. Creates the parent directory when necessary.
writeLogFile :: FilePath -> String -> Annex ()
writeLogFile f c = createDirWhenNeeded f $ viaTmp writelog f c
where
writelog f' c' = do
liftIO $ writeFile f' c'
setAnnexFilePerm f'
-- | Runs the action with a handle connected to a temp file.
-- The temp file replaces the log file once the action succeeds.
withLogHandle :: FilePath -> (Handle -> Annex a) -> Annex a
withLogHandle f a = do
createAnnexDirectory (parentDir f)
replaceFile f $ \tmp ->
bracket (setup tmp) cleanup a
where
setup tmp = do
setAnnexFilePerm tmp
liftIO $ openFile tmp WriteMode
cleanup h = liftIO $ hClose h
-- | Appends a line to a log file, first locking it to prevent
-- concurrent writers.
appendLogFile :: FilePath -> (Git.Repo -> FilePath) -> String -> Annex ()
appendLogFile f lck c = createDirWhenNeeded f $ withExclusiveLock lck $ do
liftIO $ withFile f AppendMode $ \h -> hPutStrLn h c
setAnnexFilePerm f
-- | Streams lines from a log file, and then empties the file at the end.
--
-- If the action is interrupted or throws an exception, the log file is
-- left unchanged.
--
-- Does nothing if the log file does not exist.
--
-- Locking is used to prevent writes to to the log file while this
-- is running.
streamLogFile :: FilePath -> (Git.Repo -> FilePath) -> (String -> Annex ()) -> Annex ()
streamLogFile f lck a = withExclusiveLock lck $ bracketOnError setup cleanup go
where
setup = liftIO $ tryWhenExists $ openFile f ReadMode
cleanup Nothing = noop
cleanup (Just h) = liftIO $ hClose h
go Nothing = noop
go (Just h) = do
mapM_ a =<< liftIO (lines <$> hGetContents h)
liftIO $ hClose h
liftIO $ writeFile f ""
setAnnexFilePerm f
createDirWhenNeeded :: FilePath -> Annex () -> Annex ()
createDirWhenNeeded f a = a `catchNonAsync` \_e -> do
-- Most of the time, the directory will exist, so this is only
-- done if writing the file fails.
createAnnexDirectory (parentDir f)
a