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module Network.HTTP.Semantics.File (
-- * Position read
PositionRead,
PositionReadMaker,
Sentinel (..),
defaultPositionReadMaker,
) where
import System.IO
import Network.ByteOrder
import Network.HTTP.Semantics
-- | Position read for files.
type PositionRead = FileOffset -> ByteCount -> Buffer -> IO ByteCount
-- | Making a position read and its closer.
type PositionReadMaker = FilePath -> IO (PositionRead, Sentinel)
--- | Manipulating a file resource.
data Sentinel
= -- | Closing a file resource. Its refresher is automatiaclly generated by
-- the internal timer.
Closer (IO ())
| -- | Refreshing a file resource while reading.
-- Closing the file must be done by its own timer or something.
Refresher (IO ())
-- | Position read based on 'Handle'.
defaultPositionReadMaker :: PositionReadMaker
defaultPositionReadMaker file = do
hdl <- openBinaryFile file ReadMode
return (pread hdl, Closer $ hClose hdl)
where
pread :: Handle -> PositionRead
pread hdl off bytes buf = do
hSeek hdl AbsoluteSeek $ fromIntegral off
fromIntegral <$> hGetBufSome hdl buf (fromIntegral bytes)
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