HandlePair.hs

{- |
IO into a pair of Haskell handles, like the ones
created with stdin and stdout of a forked process.
-}
module System.IO.Uniform.HandlePair (
  HandlePair,
  fromHandles
  ) where

import System.IO (Handle, hClose)
import System.IO.Uniform
import qualified Data.ByteString as BS

{- |
A pair of handles, the first for input,
and the second for output.
-}
data HandlePair = HandlePair Handle Handle

{- |
> fromHandles inputHandler outputHandler

Creates a uniform io target from a pair of handlers.
-}
fromHandles :: Handle -> Handle -> HandlePair
fromHandles = HandlePair

-- | UniformIO that reads from stdin and writes to stdout.
instance UniformIO HandlePair where
  uRead (HandlePair i _) = BS.hGetSome i
  uPut (HandlePair _ o) = BS.hPut o
  uClose (HandlePair i o) = do
    hClose i
    hClose o
  startTls _ = return
  isSecure _ = True