-{-# OPTIONS_GHC -XNoImplicitPrelude -XRecordWildCards #-}
+{-# LANGUAGE CPP
+ , NoImplicitPrelude
+ , RecordWildCards
+ , NondecreasingIndentation
+ #-}
{-# OPTIONS_GHC -fno-warn-unused-matches #-}
+
-----------------------------------------------------------------------------
-- |
-- Module : GHC.IO.Handle
import GHC.IO.Handle.Types
import GHC.IO.Handle.Internals
import GHC.IO.Handle.Text
-import System.IO.Error
+import qualified GHC.IO.BufferedIO as Buffered
import GHC.Base
import GHC.Exception
mb_exc <- hClose' h m
hClose_maybethrow mb_exc h
hClose h@(DuplexHandle _ r w) = do
- mb_exc1 <- hClose' h w
- mb_exc2 <- hClose' h r
- case mb_exc1 of
- Nothing -> return ()
- Just e -> hClose_maybethrow mb_exc2 h
+ excs <- mapM (hClose' h) [r,w]
+ hClose_maybethrow (listToMaybe (catMaybes excs)) h
hClose_maybethrow :: Maybe SomeException -> Handle -> IO ()
-hClose_maybethrow Nothing h = return ()
+hClose_maybethrow Nothing h = return ()
hClose_maybethrow (Just e) h = hClose_rethrow e h
hClose_rethrow :: SomeException -> Handle -> IO ()
-- physical file, if the current I\/O position is equal to the length of
-- the file. Otherwise, it returns 'False'.
--
--- NOTE: 'hIsEOF' may block, because it is the same as calling
--- 'hLookAhead' and checking for an EOF exception.
+-- NOTE: 'hIsEOF' may block, because it has to attempt to read from
+-- the stream to determine whether there is any more data to be read.
hIsEOF :: Handle -> IO Bool
-hIsEOF handle =
- catch
- (hLookAhead handle >> return False)
- (\e -> if isEOFError e then return True else ioError e)
+hIsEOF handle = wantReadableHandle_ "hIsEOF" handle $ \Handle__{..} -> do
+
+ cbuf <- readIORef haCharBuffer
+ if not (isEmptyBuffer cbuf) then return False else do
+
+ bbuf <- readIORef haByteBuffer
+ if not (isEmptyBuffer bbuf) then return False else do
+
+ -- NB. do no decoding, just fill the byte buffer; see #3808
+ (r,bbuf') <- Buffered.fillReadBuffer haDevice bbuf
+ if r == 0
+ then return True
+ else do writeIORef haByteBuffer bbuf'
+ return False
-- ---------------------------------------------------------------------------
-- Looking ahead
_ -> do
if mode == haBufferMode then return handle_ else do
- {- Note:
- - we flush the old buffer regardless of whether
- the new buffer could fit the contents of the old buffer
- or not.
- - allow a handle's buffering to change even if IO has
- occurred (ANSI C spec. does not allow this, nor did
- the previous implementation of IO.hSetBuffering).
- - a non-standard extension is to allow the buffering
- of semi-closed handles to change [sof 6/98]
- -}
- flushCharBuffer handle_
-
- let state = initBufferState haType
- reading = not (isWritableHandleType haType)
-
- new_buf <-
- case mode of
- -- See [note Buffer Sizing], GHC.IO.Handle.Types
- NoBuffering | reading -> newCharBuffer dEFAULT_CHAR_BUFFER_SIZE state
- | otherwise -> newCharBuffer 1 state
- LineBuffering -> newCharBuffer dEFAULT_CHAR_BUFFER_SIZE state
- BlockBuffering Nothing -> newCharBuffer dEFAULT_CHAR_BUFFER_SIZE state
- BlockBuffering (Just n) | n <= 0 -> ioe_bufsiz n
- | otherwise -> newCharBuffer n state
+ -- See [note Buffer Sizing] in GHC.IO.Handle.Types
- writeIORef haCharBuffer new_buf
+ -- check for errors:
+ case mode of
+ BlockBuffering (Just n) | n <= 0 -> ioe_bufsiz n
+ _ -> return ()
-- for input terminals we need to put the terminal into
-- cooked or raw mode depending on the type of buffering.
--
hSetEncoding :: Handle -> TextEncoding -> IO ()
hSetEncoding hdl encoding = do
- withHandle "hSetEncoding" hdl $ \h_@Handle__{..} -> do
+ withAllHandles__ "hSetEncoding" hdl $ \h_@Handle__{..} -> do
flushCharBuffer h_
+ closeTextCodecs h_
openTextEncoding (Just encoding) haType $ \ mb_encoder mb_decoder -> do
bbuf <- readIORef haByteBuffer
ref <- newIORef (error "last_decode")
return (Handle__{ haLastDecode = ref,
haDecoder = mb_decoder,
haEncoder = mb_encoder,
- haCodec = Just encoding, .. },
- ())
+ haCodec = Just encoding, .. })
-- | Return the current 'TextEncoding' for the specified 'Handle', or
-- 'Nothing' if the 'Handle' is in binary mode.
--
-- This operation may fail with:
--
+-- * 'isIllegalOperationError' if the Handle is not seekable, or does
+-- not support the requested seek mode.
+--
-- * 'isPermissionError' if a system resource limit would be exceeded.
hSeek :: Handle -> SeekMode -> Integer -> IO ()
IODevice.seek haDevice mode offset
+-- | Computation 'hTell' @hdl@ returns the current position of the
+-- handle @hdl@, as the number of bytes from the beginning of
+-- the file. The value returned may be subsequently passed to
+-- 'hSeek' to reposition the handle to the current position.
+--
+-- This operation may fail with:
+--
+-- * 'isIllegalOperationError' if the Handle is not seekable.
+--
hTell :: Handle -> IO Integer
hTell handle =
wantSeekableHandle "hGetPosn" handle $ \ handle_@Handle__{..} -> do
posn <- IODevice.tell haDevice
- cbuf <- readIORef haCharBuffer
+ -- we can't tell the real byte offset if there are buffered
+ -- Chars, so must flush first:
+ flushCharBuffer handle_
+
bbuf <- readIORef haByteBuffer
- let real_posn
- | isWriteBuffer cbuf = posn + fromIntegral (bufR cbuf)
- | otherwise = posn - fromIntegral (bufR cbuf - bufL cbuf)
- - fromIntegral (bufR bbuf - bufL bbuf)
+ let real_posn
+ | isWriteBuffer bbuf = posn + fromIntegral (bufferElems bbuf)
+ | otherwise = posn - fromIntegral (bufferElems bbuf)
+ cbuf <- readIORef haCharBuffer
debugIO ("\nhGetPosn: (posn, real_posn) = " ++ show (posn, real_posn))
debugIO (" cbuf: " ++ summaryBuffer cbuf ++
" bbuf: " ++ summaryBuffer bbuf)
withAllHandles__ "hSetBinaryMode" handle $ \ h_@Handle__{..} ->
do
flushCharBuffer h_
+ closeTextCodecs h_
let mb_te | bin = Nothing
| otherwise = Just localeEncoding
projects / ghc-base.git / blobdiff