25703e1413
Fourth or fifth try at this and finally found a way to make it work. Absurd amount of busy-work forced on me by change in cabal's behavior. Split up Utility modules that need posix stuff out of ones used by Setup. Various other hacks around inability for Setup to use anything that ifdefs a use of unix. Probably lost a full day of my life to this. This is how build systems make their users hate them. Just saying.
120 lines
4.1 KiB
Haskell
120 lines
4.1 KiB
Haskell
{- management of the git-annex journal
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-
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- The journal is used to queue up changes before they are committed to the
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- git-annex branch. Among other things, it ensures that if git-annex is
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- interrupted, its recorded data is not lost.
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-
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- Copyright 2011-2013 Joey Hess <id@joeyh.name>
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-
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- Licensed under the GNU GPL version 3 or higher.
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-}
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{-# LANGUAGE CPP #-}
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module Annex.Journal where
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import Annex.Common
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import qualified Git
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import Annex.Perms
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import Annex.LockFile
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import Utility.Directory.Stream
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{- Records content for a file in the branch to the journal.
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-
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- Using the journal, rather than immediatly staging content to the index
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- avoids git needing to rewrite the index after every change.
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-
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- The file in the journal is updated atomically, which allows
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- getJournalFileStale to always return a consistent journal file
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- content, although possibly not the most current one.
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-}
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setJournalFile :: JournalLocked -> FilePath -> String -> Annex ()
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setJournalFile _jl file content = do
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tmp <- fromRepo gitAnnexTmpMiscDir
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createAnnexDirectory =<< fromRepo gitAnnexJournalDir
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createAnnexDirectory tmp
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-- journal file is written atomically
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jfile <- fromRepo $ journalFile file
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let tmpfile = tmp </> takeFileName jfile
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liftIO $ do
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withFile tmpfile WriteMode $ \h -> do
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#ifdef mingw32_HOST_OS
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hSetNewlineMode h noNewlineTranslation
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#endif
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hPutStr h content
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moveFile tmpfile jfile
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{- Gets any journalled content for a file in the branch. -}
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getJournalFile :: JournalLocked -> FilePath -> Annex (Maybe String)
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getJournalFile _jl = getJournalFileStale
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{- Without locking, this is not guaranteed to be the most recent
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- version of the file in the journal, so should not be used as a basis for
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- changes. -}
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getJournalFileStale :: FilePath -> Annex (Maybe String)
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getJournalFileStale file = inRepo $ \g -> catchMaybeIO $
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readFileStrict $ journalFile file g
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{- List of files that have updated content in the journal. -}
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getJournalledFiles :: JournalLocked -> Annex [FilePath]
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getJournalledFiles jl = map fileJournal <$> getJournalFiles jl
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getJournalledFilesStale :: Annex [FilePath]
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getJournalledFilesStale = map fileJournal <$> getJournalFilesStale
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{- List of existing journal files. -}
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getJournalFiles :: JournalLocked -> Annex [FilePath]
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getJournalFiles _jl = getJournalFilesStale
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{- List of existing journal files, but without locking, may miss new ones
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- just being added, or may have false positives if the journal is staged
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- as it is run. -}
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getJournalFilesStale :: Annex [FilePath]
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getJournalFilesStale = do
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g <- gitRepo
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fs <- liftIO $ catchDefaultIO [] $
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getDirectoryContents $ gitAnnexJournalDir g
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return $ filter (`notElem` [".", ".."]) fs
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withJournalHandle :: (DirectoryHandle -> IO a) -> Annex a
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withJournalHandle a = do
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d <- fromRepo gitAnnexJournalDir
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bracketIO (openDirectory d) closeDirectory (liftIO . a)
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{- Checks if there are changes in the journal. -}
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journalDirty :: Annex Bool
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journalDirty = do
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d <- fromRepo gitAnnexJournalDir
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liftIO $
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(not <$> isDirectoryEmpty d)
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`catchIO` (const $ doesDirectoryExist d)
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{- Produces a filename to use in the journal for a file on the branch.
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-
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- The journal typically won't have a lot of files in it, so the hashing
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- used in the branch is not necessary, and all the files are put directly
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- in the journal directory.
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-}
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journalFile :: FilePath -> Git.Repo -> FilePath
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journalFile file repo = gitAnnexJournalDir repo </> concatMap mangle file
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where
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mangle c
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| c == pathSeparator = "_"
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| c == '_' = "__"
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| otherwise = [c]
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{- Converts a journal file (relative to the journal dir) back to the
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- filename on the branch. -}
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fileJournal :: FilePath -> FilePath
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fileJournal = replace [pathSeparator, pathSeparator] "_" .
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replace "_" [pathSeparator]
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{- Sentinal value, only produced by lockJournal; required
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- as a parameter by things that need to ensure the journal is
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- locked. -}
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data JournalLocked = ProduceJournalLocked
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{- Runs an action that modifies the journal, using locking to avoid
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- contention with other git-annex processes. -}
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lockJournal :: (JournalLocked -> Annex a) -> Annex a
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lockJournal a = withExclusiveLock gitAnnexJournalLock $ a ProduceJournalLocked
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