diff options
author | 2012-06-13 01:20:37 -0400 | |
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committer | 2012-06-13 01:20:37 -0400 | |
commit | 12dbb9d1d0162d5417805503525f30faf9aa2fc2 (patch) | |
tree | 77cf7c2b0452c0720fd1e8ebfa974289117806ae /Utility/Inotify.hs | |
parent | ab076b2e818e616c1049ec1119d77ca2ff2e3a17 (diff) |
plumb file status through to event handlers
The idea, not yet done, is to use this to detect when a file
has an old change time, and avoid expensive restaging of the file.
If git-annex watch keeps track of the last time it finished a full scan,
then any symlink that is older than that time must have been scanned
before, so need not be added. (Relying on moving, copying, etc of a file
all updating its change time.)
Anyway, this info is available for free since inotify already checks it,
so it might as well make it available.
Diffstat (limited to 'Utility/Inotify.hs')
-rw-r--r-- | Utility/Inotify.hs | 49 |
1 files changed, 28 insertions, 21 deletions
diff --git a/Utility/Inotify.hs b/Utility/Inotify.hs index 6eb7be31c..9ad947f31 100644 --- a/Utility/Inotify.hs +++ b/Utility/Inotify.hs @@ -15,7 +15,7 @@ import qualified System.Posix.Files as Files import System.IO.Error import Control.Exception (throw) -type Hook a = Maybe (a -> IO ()) +type Hook a = Maybe (a -> Maybe FileStatus -> IO ()) data WatchHooks = WatchHooks { addHook :: Hook FilePath @@ -84,15 +84,18 @@ watchDir i dir ignored hooks | otherwise = [] scan f = unless (ignored f) $ do - let fullf = indir f - r <- catchMaybeIO $ getSymbolicLinkStatus fullf - case r of + ms <- getstatus f + case ms of Nothing -> return () Just s - | Files.isDirectory s -> recurse fullf - | Files.isSymbolicLink s -> addSymlinkHook <@> f - | Files.isRegularFile s -> addHook <@> f - | otherwise -> return () + | Files.isDirectory s -> + recurse $ indir f + | Files.isSymbolicLink s -> + runhook addSymlinkHook f ms + | Files.isRegularFile s -> + runhook addHook f ms + | otherwise -> + noop -- Ignore creation events for regular files, which won't be -- done being written when initially created, but handle for @@ -100,39 +103,43 @@ watchDir i dir ignored hooks go (Created { isDirectory = isd, filePath = f }) | isd = recurse $ indir f | hashook addSymlinkHook = - whenM (filetype Files.isSymbolicLink f) $ - addSymlinkHook <@> f + checkfiletype Files.isSymbolicLink addSymlinkHook f | otherwise = noop -- Closing a file is assumed to mean it's done being written. go (Closed { isDirectory = False, maybeFilePath = Just f }) = - whenM (filetype Files.isRegularFile f) $ - addHook <@> f + checkfiletype Files.isRegularFile addHook f -- When a file or directory is moved in, scan it to add new -- stuff. go (MovedIn { filePath = f }) = scan f go (MovedOut { isDirectory = isd, filePath = f }) - | isd = delDirHook <@> f - | otherwise = delHook <@> f + | isd = runhook delDirHook f Nothing + | otherwise = runhook delHook f Nothing -- Verify that the deleted item really doesn't exist, -- since there can be spurious deletion events for items -- in a directory that has been moved out, but is still -- being watched. go (Deleted { isDirectory = isd, filePath = f }) - | isd = guarded $ delDirHook <@> f - | otherwise = guarded $ delHook <@> f + | isd = guarded $ runhook delDirHook f Nothing + | otherwise = guarded $ runhook delHook f Nothing where guarded = unlessM (filetype (const True) f) go _ = noop hashook h = isJust $ h hooks - runhook h f + runhook h f s | ignored f = noop - | otherwise = maybe noop (\a -> a $ indir f) (h hooks) - h <@> f = runhook h f + | otherwise = maybe noop (\a -> a (indir f) s) (h hooks) indir f = dir </> f + getstatus f = catchMaybeIO $ getSymbolicLinkStatus $ indir f + checkfiletype check h f = do + ms <- getstatus f + case ms of + Just s + | check s -> runhook h f ms + _ -> noop filetype t f = catchBoolIO $ t <$> getSymbolicLinkStatus (indir f) -- Inotify fails when there are too many watches with a @@ -144,10 +151,10 @@ watchDir i dir ignored hooks Just hook -> tooManyWatches hook dir | otherwise = throw e -tooManyWatches :: (String -> IO ()) -> FilePath -> IO () +tooManyWatches :: (String -> Maybe FileStatus -> IO ()) -> FilePath -> IO () tooManyWatches hook dir = do sysctlval <- querySysctl [Param maxwatches] :: IO (Maybe Integer) - hook $ unlines $ basewarning : maybe withoutsysctl withsysctl sysctlval + hook (unlines $ basewarning : maybe withoutsysctl withsysctl sysctlval) Nothing where maxwatches = "fs.inotify.max_user_watches" basewarning = "Too many directories to watch! (Not watching " ++ dir ++")" |