git-annex/Assistant/Changes.hs
Joey Hess 33b914bcf1 pending adds now retried for kqueue
Rethought how to keep track of pending adds that need to be retried later.
The commit thread already run up every second when there are changes,
so let's keep pending adds queued as changes until they're safe to add.

Also, the committer is now smarter about avoiding empty commits when
all the adds are currently unsafe, or in the rare case that an add event
for a symlink is not received in time. It may avoid them entirely.

This seems to work as before for inotify, and is untested for kqueue.

(Actually commit batching seems to be improved for inotify, although I'm
not sure why. I'm seeing only two commits made during large batch
operations, and the first of those is the non-batch mode commit.)
2012-06-20 19:29:53 -04:00

81 lines
2.1 KiB
Haskell

{- git-annex assistant change tracking
-
- Copyright 2012 Joey Hess <joey@kitenet.net>
-}
module Assistant.Changes where
import Common.Annex
import qualified Annex.Queue
import Types.KeySource
import Control.Concurrent.STM
import Data.Time.Clock
data ChangeType = AddChange | LinkChange | RmChange | RmDirChange
deriving (Show, Eq)
type ChangeChan = TChan Change
data Change
= Change
{ changeTime :: UTCTime
, changeFile :: FilePath
, changeType :: ChangeType
}
| PendingAddChange
{ changeTime ::UTCTime
, keySource :: KeySource
}
deriving (Show)
runChangeChan :: STM a -> IO a
runChangeChan = atomically
newChangeChan :: IO ChangeChan
newChangeChan = atomically newTChan
{- Handlers call this when they made a change that needs to get committed. -}
madeChange :: FilePath -> ChangeType -> Annex (Maybe Change)
madeChange f t = do
-- Just in case the commit thread is not flushing the queue fast enough.
Annex.Queue.flushWhenFull
liftIO $ Just <$> (Change <$> getCurrentTime <*> pure f <*> pure t)
noChange :: Annex (Maybe Change)
noChange = return Nothing
{- Indicates an add is in progress. -}
pendingAddChange :: KeySource -> Annex (Maybe Change)
pendingAddChange ks =
liftIO $ Just <$> (PendingAddChange <$> getCurrentTime <*> pure ks)
isPendingAddChange :: Change -> Bool
isPendingAddChange (PendingAddChange {}) = True
isPendingAddChange _ = False
finishedChange :: Change -> Change
finishedChange c@(PendingAddChange { keySource = ks }) = Change
{ changeTime = changeTime c
, changeFile = keyFilename ks
, changeType = AddChange
}
finishedChange c = c
{- Gets all unhandled changes.
- Blocks until at least one change is made. -}
getChanges :: ChangeChan -> IO [Change]
getChanges chan = runChangeChan $ do
c <- readTChan chan
go [c]
where
go l = do
v <- tryReadTChan chan
case v of
Nothing -> return l
Just c -> go (c:l)
{- Puts unhandled changes back into the channel.
- Note: Original order is not preserved. -}
refillChanges :: ChangeChan -> [Change] -> IO ()
refillChanges chan cs = runChangeChan $ mapM_ (writeTChan chan) cs