diff options
Diffstat (limited to 'Utility/Kqueue.hs')
| -rw-r--r-- | Utility/Kqueue.hs | 40 |
1 files changed, 25 insertions, 15 deletions
diff --git a/Utility/Kqueue.hs b/Utility/Kqueue.hs index e8ce73b26..a3d8aff2d 100644 --- a/Utility/Kqueue.hs +++ b/Utility/Kqueue.hs @@ -25,6 +25,8 @@ import qualified Data.Map as M type DirMap = M.Map Fd FilePath +data Kqueue = Kqueue Fd DirMap + {- Builds a map of directories in a tree, possibly pruning some. - Opens each directory in the tree. -} scanRecursive :: FilePath -> (FilePath -> Bool) -> IO DirMap @@ -43,25 +45,33 @@ addSubDir dirmap dir prune = M.union dirmap <$> scanRecursive dir prune removeSubDir :: FilePath -> DirMap -> DirMap removeSubDir dir = M.filter (not . dirContains dir) -foreign import ccall unsafe "libkqueue.h waitchange" c_waitchange - :: Ptr Fd -> IO Fd +foreign import ccall unsafe "libkqueue.h init_kqueue" c_init_kqueue + :: CInt -> Ptr Fd -> IO Fd +foreign import ccall unsafe "libkqueue.h waitchange_kqueue" c_waitchange_kqueue + :: Fd -> IO Fd + +{- Initializes a Kqueue to watch a map of directories. -} +initKqueue :: DirMap -> IO Kqueue +initKqueue dirmap = withArrayLen (M.keys dirmap) $ \fdcnt c_fds -> + h <- c_init_kqueue (fromIntegral fdcnt) c_fds + return $ Kqueue h dirmap -{- Waits for a change in a map of directories, and returns the directory - - where the change took place. +{- Stops a Kqueue. Note: Does not directly close the Fds in the dirmap, + - so it can be reused. -} +stopKqueue :: Kqueue -> IO +stopKqueue (Kqueue h _) = closeFd h + +{- Waits for a change on a Kqueue, and returns the directory + - or directories where a change took place. - - The kqueue interface does not tell what type of change took place in - the directory; it could be an added file, a deleted file, a renamed - file, a new subdirectory, or a deleted subdirectory, or a moved - subdirectory. - - - Note that if subdirectories have changed, the caller will want to - - update the map before calling this again. -} -waitChange :: DirMap -> IO (Maybe FilePath) -waitChange dirmap = withArray (M.keys dirmap) $ \c_fds -> do - changed <- c_waitchange c_fds - ifM (safeErrno <$> getErrno) - ( return $ M.lookup changed dirmap - , return Nothing - ) - where - safeErrno (Errno v) = v == 0 + - Note that if subdirectories have changed, the caller should re-run + - initKqueue to get them watched. -} +waitChange :: Kqueue -> IO [FilePath] +waitChange (Kqueue h dirmap) = do + changed <- c_waitchange_kqueue h + return $ M.lookup changed dirmap |