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|
-----------------------------------------------------------------------------
-- |
-- Module : Plugins.Mail
-- Copyright : (c) Spencer Janssen
-- License : BSD-style (see LICENSE)
--
-- Maintainer : Spencer Janssen <sjanssen@cse.unl.edu>
-- Stability : unstable
-- Portability : unportable
--
-- A plugin for checking mail.
--
-----------------------------------------------------------------------------
module Plugins.Mail where
import Prelude hiding (catch)
import Plugins
import Control.Monad
import Control.Concurrent.STM
import System.Directory
import System.FilePath
import System.INotify
import Data.List (isPrefixOf)
import Data.Set (Set)
import qualified Data.Set as S
-- | A list of mail box names and paths to maildirs.
data Mail = Mail [(String, FilePath)]
deriving (Read, Show)
instance Exec Mail where
start (Mail ms) cb = do
vs <- mapM (const $ newTVarIO S.empty) ms
let ts = map fst ms
ds = map ((</> "new") . snd) ms
ev = [Move, MoveIn, MoveOut, Create, Delete]
i <- initINotify
zipWithM_ (\d v -> addWatch i ev d (handle v)) ds vs
forM (zip ds vs) $ \(d, v) -> do
s <- fmap (S.fromList . filter (not . isPrefixOf "."))
$ getDirectoryContents d
atomically $ modifyTVar v (S.union s)
changeLoop (mapM (fmap S.size . readTVar) vs) $ \ns -> do
cb . unwords $ [m ++ ":" ++ show n
| (m, n) <- zip ts ns
, n /= 0 ]
modifyTVar :: TVar a -> (a -> a) -> STM ()
modifyTVar v f = readTVar v >>= writeTVar v . f
handle :: TVar (Set String) -> Event -> IO ()
handle v e = atomically $ modifyTVar v $ case e of
Created {} -> create
MovedIn {} -> create
Deleted {} -> delete
MovedOut {} -> delete
_ -> id
where
delete = S.delete (filePath e)
create = S.insert (filePath e)
changeLoop :: Eq a => STM a -> (a -> IO ()) -> IO ()
changeLoop s f = atomically s >>= go
where
go old = do
f old
go =<< atomically (do
new <- s
guard (new /= old)
return new)
|
