diff options
Diffstat (limited to 'Annex/Journal.hs')
| -rw-r--r-- | Annex/Journal.hs | 54 |
1 files changed, 39 insertions, 15 deletions
diff --git a/Annex/Journal.hs b/Annex/Journal.hs index fff20ccc4..8b88ab2fb 100644 --- a/Annex/Journal.hs +++ b/Annex/Journal.hs @@ -1,10 +1,10 @@ {- management of the git-annex journal - - The journal is used to queue up changes before they are committed to the - - git-annex branch. Amoung other things, it ensures that if git-annex is + - git-annex branch. Among other things, it ensures that if git-annex is - interrupted, its recorded data is not lost. - - - Copyright 2011 Joey Hess <joey@kitenet.net> + - Copyright 2011-2013 Joey Hess <joey@kitenet.net> - - Licensed under the GNU GPL version 3 or higher. -} @@ -23,9 +23,14 @@ import Annex.Perms {- Records content for a file in the branch to the journal. - - Using the journal, rather than immediatly staging content to the index - - avoids git needing to rewrite the index after every change. -} -setJournalFile :: FilePath -> String -> Annex () -setJournalFile file content = do + - avoids git needing to rewrite the index after every change. + - + - The file in the journal is updated atomically, which allows + - getJournalFileStale to always return a consistent journal file + - content, although possibly not the most current one. + -} +setJournalFile :: JournalLocked -> FilePath -> String -> Annex () +setJournalFile _jl file content = do createAnnexDirectory =<< fromRepo gitAnnexJournalDir createAnnexDirectory =<< fromRepo gitAnnexTmpDir -- journal file is written atomically @@ -37,17 +42,32 @@ setJournalFile file content = do moveFile tmpfile jfile {- Gets any journalled content for a file in the branch. -} -getJournalFile :: FilePath -> Annex (Maybe String) -getJournalFile file = inRepo $ \g -> catchMaybeIO $ +getJournalFile :: JournalLocked -> FilePath -> Annex (Maybe String) +getJournalFile _jl = getJournalFileStale + +{- Without locking, this is not guaranteed to be the most recent + - version of the file in the journal, so should not be used as a basis for + - changes. -} +getJournalFileStale :: FilePath -> Annex (Maybe String) +getJournalFileStale file = inRepo $ \g -> catchMaybeIO $ readFileStrict $ journalFile file g {- List of files that have updated content in the journal. -} -getJournalledFiles :: Annex [FilePath] -getJournalledFiles = map fileJournal <$> getJournalFiles +getJournalledFiles :: JournalLocked -> Annex [FilePath] +getJournalledFiles jl = map fileJournal <$> getJournalFiles jl + +getJournalledFilesStale :: Annex [FilePath] +getJournalledFilesStale = map fileJournal <$> getJournalFilesStale {- List of existing journal files. -} -getJournalFiles :: Annex [FilePath] -getJournalFiles = do +getJournalFiles :: JournalLocked -> Annex [FilePath] +getJournalFiles _jl = getJournalFilesStale + +{- List of existing journal files, but without locking, may miss new ones + - just being added, or may have false positives if the journal is staged + - as it is run. -} +getJournalFilesStale :: Annex [FilePath] +getJournalFilesStale = do g <- gitRepo fs <- liftIO $ catchDefaultIO [] $ getDirectoryContents $ gitAnnexJournalDir g @@ -55,7 +75,7 @@ getJournalFiles = do {- Checks if there are changes in the journal. -} journalDirty :: Annex Bool -journalDirty = not . null <$> getJournalFiles +journalDirty = not . null <$> getJournalFilesStale {- Produces a filename to use in the journal for a file on the branch. - @@ -77,14 +97,19 @@ fileJournal :: FilePath -> FilePath fileJournal = replace [pathSeparator, pathSeparator] "_" . replace "_" [pathSeparator] +{- Sentinal value, only produced by lockJournal; required + - as a parameter by things that need to ensure the journal is + - locked. -} +data JournalLocked = ProduceJournalLocked + {- Runs an action that modifies the journal, using locking to avoid - contention with other git-annex processes. -} -lockJournal :: Annex a -> Annex a +lockJournal :: (JournalLocked -> Annex a) -> Annex a lockJournal a = do lockfile <- fromRepo gitAnnexJournalLock createAnnexDirectory $ takeDirectory lockfile mode <- annexFileMode - bracketIO (lock lockfile mode) unlock (const a) + bracketIO (lock lockfile mode) unlock (const $ a ProduceJournalLocked) where #ifndef mingw32_HOST_OS lock lockfile mode = do @@ -101,4 +126,3 @@ lockJournal a = do #else unlock = removeFile #endif - |