{-# LANGUAGE OverloadedStrings #-}
{-# LANGUAGE TupleSections #-}
module Stack.FileWatch
( fileWatch
, fileWatchPoll
, printExceptionStderr
) where
import Blaze.ByteString.Builder (toLazyByteString, copyByteString)
import Blaze.ByteString.Builder.Char.Utf8 (fromShow)
import Control.Concurrent.Async (race_)
import Control.Concurrent.STM
import Control.Exception (Exception, fromException)
import Control.Exception.Enclosed (tryAny)
import Control.Monad (forever, unless, when)
import qualified Data.ByteString.Lazy as L
import qualified Data.Map.Strict as Map
import Data.Monoid ((<>))
import Data.Set (Set)
import qualified Data.Set as Set
import Data.String (fromString)
import Data.Traversable (forM)
import GHC.IO.Handle (hIsTerminalDevice)
import Path
import System.Console.ANSI
import System.Exit
import System.FSNotify
import System.IO (stdout, stderr)
printExceptionStderr :: Exception e => e -> IO ()
printExceptionStderr e =
L.hPut stderr $ toLazyByteString $ fromShow e <> copyByteString "\n"
fileWatch :: ((Set (Path Abs File) -> IO ()) -> IO ())
-> IO ()
fileWatch = fileWatchConf defaultConfig
fileWatchPoll :: ((Set (Path Abs File) -> IO ()) -> IO ())
-> IO ()
fileWatchPoll = fileWatchConf $ defaultConfig { confUsePolling = True }
fileWatchConf :: WatchConfig
-> ((Set (Path Abs File) -> IO ()) -> IO ())
-> IO ()
fileWatchConf cfg inner = withManagerConf cfg $ \manager -> do
allFiles <- newTVarIO Set.empty
dirtyVar <- newTVarIO True
watchVar <- newTVarIO Map.empty
let onChange event = atomically $ do
files <- readTVar allFiles
when (eventPath event `Set.member` files) (writeTVar dirtyVar True)
setWatched :: Set (Path Abs File) -> IO ()
setWatched files = do
atomically $ writeTVar allFiles $ Set.map toFilePath files
watch0 <- readTVarIO watchVar
let actions = Map.mergeWithKey
keepListening
stopListening
startListening
watch0
newDirs
watch1 <- forM (Map.toList actions) $ \(k, mmv) -> do
mv <- mmv
return $
case mv of
Nothing -> Map.empty
Just v -> Map.singleton k v
atomically $ writeTVar watchVar $ Map.unions watch1
where
newDirs = Map.fromList $ map (, ())
$ Set.toList
$ Set.map parent files
keepListening _dir listen () = Just $ return $ Just listen
stopListening = Map.map $ \f -> do
() <- f
return Nothing
startListening = Map.mapWithKey $ \dir () -> do
let dir' = fromString $ toFilePath dir
listen <- watchDir manager dir' (const True) onChange
return $ Just listen
let watchInput = do
line <- getLine
unless (line == "quit") $ do
case line of
"help" -> do
putStrLn ""
putStrLn "help: display this help"
putStrLn "quit: exit"
putStrLn "build: force a rebuild"
putStrLn "watched: display watched files"
"build" -> atomically $ writeTVar dirtyVar True
"watched" -> do
watch <- readTVarIO allFiles
mapM_ putStrLn (Set.toList watch)
"" -> atomically $ writeTVar dirtyVar True
_ -> putStrLn $ concat
[ "Unknown command: "
, show line
, ". Try 'help'"
]
watchInput
race_ watchInput $ forever $ do
atomically $ do
dirty <- readTVar dirtyVar
check dirty
eres <- tryAny $ inner setWatched
atomically $ writeTVar dirtyVar False
let withColor color action = do
outputIsTerminal <- hIsTerminalDevice stdout
if outputIsTerminal
then do
setSGR [SetColor Foreground Dull color]
action
setSGR [Reset]
else action
case eres of
Left e -> do
let color = case fromException e of
Just ExitSuccess -> Green
_ -> Red
withColor color $ printExceptionStderr e
_ -> withColor Green $
putStrLn "Success! Waiting for next file change."
putStrLn "Type help for available commands. Press enter to force a rebuild."