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|
{-# LANGUAGE OverloadedStrings #-}
-- Server.hs - UNIX socket server for RDE remote control
--
-- Note: This module requires the 'network' and 'stm' packages to be installed.
-- Add them to package.yaml:
-- dependencies:
-- - network
-- - stm
module Rahm.Desktop.Server where
import Control.Concurrent
import Control.Concurrent.STM
import Control.Exception (finally, throwIO, try)
import Control.Monad (forever, void, when)
import Control.Monad.Fix
import Control.Monad.IO.Class (liftIO)
import Control.Monad.RWS (All (All))
import qualified Data.ByteString as BS
import qualified Data.ByteString.Char8 as BSC
import Data.Maybe (fromMaybe)
import Graphics.X11.Xlib
import Graphics.X11.Xlib.Extras (Event (..), currentTime, setClientMessageEvent, setEventType)
import Network.Socket
import Network.Socket.ByteString (recv, sendAll)
import System.Directory
import System.Environment (lookupEnv)
import System.FilePath ((</>))
import System.IO
import System.IO.Error (isEOFError)
import XMonad (X, XConfig (handleEventHook), io)
data CommandHandler c where
CommandHandler ::
{ parser :: String -> Maybe c,
handler :: c -> X ()
} ->
CommandHandler c
(<<>>) :: CommandHandler c1 -> CommandHandler c2 -> CommandHandler (Either c1 c2)
(<<>>) c1 c2 =
CommandHandler
( \str -> case (parser c1 str, parser c2 str) of
(Just l, _) -> Just (Left l)
(_, Just r) -> Just (Right r)
_ -> Nothing
)
( \case
Right r -> handler c2 r
Left l -> handler c1 l
)
data ServerContext c where
ServerContext ::
{ display :: Display,
rootWin :: Window,
eventType :: Atom,
commandHandler :: CommandHandler c,
channel :: TChan c
} ->
ServerContext c
enableServerMode :: CommandHandler c -> XConfig l -> IO (XConfig l)
enableServerMode handler xconfig = do
serverCtx <- forkServer handler
return $
xconfig
{ handleEventHook =
eventHandler serverCtx <> handleEventHook xconfig
}
socketPath :: IO FilePath
socketPath = do
dir <- fromMaybe "/tmp/rde" <$> lookupEnv "XDG_RUNTIME_DIR"
display <- fromMaybe ":0" <$> lookupEnv "DISPLAY"
createDirectoryIfMissing True dir
return (dir </> "rde-" <> dropWhile (== ':') display <> ".sock")
forkServer :: CommandHandler c -> IO (ServerContext c)
forkServer handler = do
chan <- atomically newTChan
path <- socketPath
-- Remove stale socket if it exists
exists <- doesPathExist path
when exists $ removeFile path
sock <- socket AF_UNIX Stream defaultProtocol
bind sock (SockAddrUnix path)
listen sock 5
putStrLn $ "Listening on " ++ path
dpy <- getDefaultDisplay
let screen = defaultScreen dpy
win <- rootWindow dpy screen
eventType <- internAtom dpy "RDE_COMMAND_NOTIFY" True
let ctx = ServerContext dpy win eventType handler chan
forkIO $ do
hFlush stdout
forever $ do
(conn, _) <- accept sock
hFlush stdout
void $ forkIO $ handleClient ctx conn
return ctx
handleClient :: ServerContext c -> Socket -> IO ()
handleClient chan conn =
finally (loop BS.empty) (close conn)
where
loop buf = do
chunk <- recv conn 4096
if BS.null chunk
then return () -- connection closed
else do
let buf' = buf <> chunk
(lines, rest) = splitLines buf'
mapM_ (handleLine chan . BSC.unpack) lines
loop rest
splitLines :: BS.ByteString -> ([BS.ByteString], BS.ByteString)
splitLines bs =
case BSC.break (== '\n') bs of
(line, rest)
| BS.null rest -> ([], bs)
| otherwise ->
let remaining = BS.drop 1 rest
(ls, r) = splitLines remaining
in (line : ls, r)
handleLine :: ServerContext c -> String -> IO ()
handleLine ctx line = case parser (commandHandler ctx) line of
Just s -> pushChan s
_ -> hPutStrLn stderr $ "Unable to parse command `" ++ line ++ "`"
where
pushChan c = do
atomically $ writeTChan (channel ctx) c
raiseNotifyEvent ctx
raiseNotifyEvent :: ServerContext c -> IO ()
raiseNotifyEvent ServerContext {display = dpy, rootWin = root, eventType = ty} =
allocaXEvent $ \evPtr -> do
m <- internAtom dpy "" False
setEventType evPtr clientMessage
setClientMessageEvent evPtr root ty 32 m currentTime
sendEvent dpy root False structureNotifyMask evPtr
flush dpy
eventHandler :: ServerContext c -> Event -> X All
eventHandler
ServerContext
{ display = dpy,
rootWin = root,
eventType = ty,
channel = chan,
commandHandler = commandHandler
}
e@ClientMessageEvent {ev_message_type = atom} = do
if atom == ty
then do
mapM_ (handler commandHandler) =<< io (atomically (tryReadTChan chan))
return (All True)
else return (All True)
eventHandler _ _ = return (All True)
getDefaultDisplay :: IO Display
getDefaultDisplay = openDisplay ""
|
