ghcup-hs/lib/System/Console/Terminal/Posix.hsc
Julian Ospald 15dd810d67
Get rid of concurrent-output
Also improve some NO_COLOR foo.
2021-09-24 23:49:50 +02:00

66 lines
1.8 KiB
Haskell

{-# LANGUAGE CApiFFI #-}
module System.Console.Terminal.Posix
( size, fdSize, hSize
) where
import System.Console.Terminal.Common
import Control.Exception (catch)
import Data.Typeable (cast)
import Foreign
import Foreign.C.Error
import Foreign.C.Types
import GHC.IO.FD (FD(FD, fdFD))
import GHC.IO.Handle.Internals (withHandle_)
import GHC.IO.Handle.Types (Handle, Handle__(Handle__, haDevice))
#if defined(__GLASGOW_HASKELL__) && (__GLASGOW_HASKELL__ < 706)
import Prelude hiding (catch)
#endif
import System.Posix.Types (Fd(Fd))
#include <sys/ioctl.h>
#include <unistd.h>
#let alignment t = "%lu", (unsigned long)offsetof(struct {char x__; t (y__); }, y__)
-- Interesting part of @struct winsize@
data CWin = CWin CUShort CUShort
instance Storable CWin where
sizeOf _ = (#size struct winsize)
alignment _ = (#alignment struct winsize)
peek ptr = do
row <- (#peek struct winsize, ws_row) ptr
col <- (#peek struct winsize, ws_col) ptr
return $ CWin row col
poke ptr (CWin row col) = do
(#poke struct winsize, ws_row) ptr row
(#poke struct winsize, ws_col) ptr col
fdSize :: Integral n => Fd -> IO (Maybe (Window n))
fdSize (Fd fd) = with (CWin 0 0) $ \ws -> do
_ <- throwErrnoIfMinus1 "ioctl" $
ioctl fd (#const TIOCGWINSZ) ws
CWin row col <- peek ws
return . Just $ Window (fromIntegral row) (fromIntegral col)
`catch`
handler
where
handler :: IOError -> IO (Maybe (Window h))
handler _ = return Nothing
foreign import capi "sys/ioctl.h ioctl"
ioctl :: CInt -> CULong -> Ptr CWin -> IO CInt
size :: Integral n => IO (Maybe (Window n))
size = fdSize (Fd (#const STDOUT_FILENO))
hSize :: Integral n => Handle -> IO (Maybe (Window n))
hSize h = withHandle_ "hSize" h $ \Handle__ { haDevice = dev } ->
case cast dev of
Nothing -> return Nothing
Just FD { fdFD = fd } -> fdSize (Fd fd)