Backend.hs

module System.Console.Haskeline.Backend where

import System.Console.Haskeline.Term
import System.Console.Haskeline.Monads
import Control.Monad
import System.IO (stdin, hGetEcho, Handle)

#ifdef MINGW
import System.Console.Haskeline.Backend.Win32 as Win32
#else
import System.Console.Haskeline.Backend.Posix as Posix
#ifdef TERMINFO
import System.Console.Haskeline.Backend.Terminfo as Terminfo
#endif
import System.Console.Haskeline.Backend.DumbTerm as DumbTerm
#endif


defaultRunTerm :: IO RunTerm
defaultRunTerm = (liftIO (hGetEcho stdin) >>= guard >> stdinTTY)
                    `orElse` fileHandleRunTerm stdin

terminalRunTerm :: IO RunTerm
terminalRunTerm = directTTY `orElse` fileHandleRunTerm stdin

#ifndef MINGW
useTermHandlesRunTerm :: Maybe String -> Handle -> Handle -> IO RunTerm
useTermHandlesRunTerm termtype input output =
    explicitTTY termtype input output `orElse` fileHandleRunTerm input
#endif

stdinTTY :: MaybeT IO RunTerm
#ifdef MINGW
stdinTTY = win32TermStdin
#else
stdinTTY = stdinTTYHandles >>= runDraw Nothing
#endif

directTTY :: MaybeT IO RunTerm
#ifdef MINGW
directTTY = win32Term
#else
directTTY = ttyHandles >>= runDraw Nothing
#endif

#ifndef MINGW
explicitTTY :: Maybe String -> Handle -> Handle -> MaybeT IO RunTerm
explicitTTY termtype input output =
    explicitTTYHandles input output >>= runDraw termtype
#endif


#ifndef MINGW
runDraw :: Maybe String -> Handles -> MaybeT IO RunTerm
#ifndef TERMINFO
runDraw _termtype = runDumbTerm
#else
runDraw termtype h = runTerminfoDraw termtype h `mplus` runDumbTerm h
#endif
#endif

fileHandleRunTerm :: Handle -> IO RunTerm
#ifdef MINGW
fileHandleRunTerm = Win32.fileRunTerm
#else
fileHandleRunTerm = Posix.fileRunTerm
#endif