import PrelRead ( readParen, Read(..), reads, lex,
readIO
)
---import PrelNum ( toInteger )
-import PrelBounded () -- Bounded Int instance.
-import PrelEither ( Either(..) )
+import PrelShow
+import PrelMaybe ( Either(..), Maybe(..) )
import PrelAddr ( Addr(..), nullAddr )
import PrelArr ( ByteArray )
import PrelPack ( unpackNBytesAccST )
#ifndef HEAD
#ifdef __HUGS__
-#define cat2(x,y) x/**/y
+#define cat2(x,y) x##y
#define CCALL(fun) cat2(prim_,fun)
#define __CONCURRENT_HASKELL__
#define stToIO id
hWaitForInput handle msecs =
wantReadableHandle "hWaitForInput" handle $ \ handle_ -> do
rc <- CCALL(inputReady) (haFO__ handle_) (msecs::Int) -- ConcHask: SAFE, won't block
- writeHandle handle handle_
case (rc::Int) of
0 -> return False
1 -> return True
wantReadableHandle "hGetChar" handle $ \ handle_ -> do
let fo = haFO__ handle_
intc <- mayBlock fo (CCALL(fileGetc) fo) -- ConcHask: UNSAFE, may block
- writeHandle handle handle_
if intc /= ((-1)::Int)
then return (chr intc)
else constructErrorAndFail "hGetChar"
+{-
+ If EOF is reached before EOL is encountered, ignore the
+ EOF and return the partial line. Next attempt at calling
+ hGetLine on the handle will yield an EOF IO exception though.
+-}
hGetLine :: Handle -> IO String
hGetLine h = do
c <- hGetChar h
- if c == '\n'
- then return ""
+ if c == '\n' then
+ return ""
else do
- s <- hGetLine h
- return (c:s)
+ l <- getRest
+ return (c:l)
+ where
+ getRest = do
+ c <-
+ catch
+ (hGetChar h)
+ (\ err -> do
+ if isEOFError err then
+ return '\n'
+ else
+ ioError err)
+ if c == '\n' then
+ return ""
+ else do
+ s <- getRest
+ return (c:s)
\end{code}
\begin{code}
hLookAhead :: Handle -> IO Char
-hLookAhead handle = do
+hLookAhead handle =
wantReadableHandle "hLookAhead" handle $ \ handle_ -> do
let fo = haFO__ handle_
intc <- mayBlock fo (CCALL(fileLookAhead) fo) -- ConcHask: UNSAFE, may block
- writeHandle handle handle_
if intc /= (-1)
then return (chr intc)
else constructErrorAndFail "hLookAhead"
\begin{code}
hGetContents :: Handle -> IO String
hGetContents handle =
- wantReadableHandle "hGetContents" handle $ \ handle_ -> do
- {-
- To avoid introducing an extra layer of buffering here,
- we provide three lazy read methods, based on character,
- line, and block buffering.
- -}
- writeHandle handle (handle_{ haType__ = SemiClosedHandle })
- case (haBufferMode__ handle_) of
- LineBuffering -> unsafeInterleaveIO (lazyReadLine handle (haFO__ handle_))
- BlockBuffering _ -> unsafeInterleaveIO (lazyReadBlock handle (haFO__ handle_))
- NoBuffering -> unsafeInterleaveIO (lazyReadChar handle (haFO__ handle_))
-
+ -- can't use wantReadableHandle here, because we want to side effect
+ -- the handle.
+ withHandle handle $ \ handle_ -> do
+ case haType__ handle_ of
+ ErrorHandle theError -> ioError theError
+ ClosedHandle -> ioe_closedHandle "hGetContents" handle
+ SemiClosedHandle -> ioe_closedHandle "hGetContents" handle
+ AppendHandle -> ioError not_readable_error
+ WriteHandle -> ioError not_readable_error
+ _ -> do
+ {-
+ To avoid introducing an extra layer of buffering here,
+ we provide three lazy read methods, based on character,
+ line, and block buffering.
+ -}
+ let handle_' = handle_{ haType__ = SemiClosedHandle }
+ case (haBufferMode__ handle_) of
+ LineBuffering -> do
+ str <- unsafeInterleaveIO (lazyReadLine handle (haFO__ handle_))
+ return (handle_', str)
+ BlockBuffering _ -> do
+ str <- unsafeInterleaveIO (lazyReadBlock handle (haFO__ handle_))
+ return (handle_', str)
+ NoBuffering -> do
+ str <- unsafeInterleaveIO (lazyReadChar handle (haFO__ handle_))
+ return (handle_', str)
+ where
+ not_readable_error =
+ IOError (Just handle) IllegalOperation "hGetContents"
+ ("handle is not open for reading")
\end{code}
Note that someone may close the semi-closed handle (or change its buffering),
-1 -> -- an error occurred, close the handle
withHandle handle $ \ handle_ -> do
CCALL(closeFile) (haFO__ handle_) (0::Int){-don't bother flushing-} -- ConcHask: SAFE, won't block.
- writeHandle handle (handle_ { haType__ = ClosedHandle,
- haFO__ = nullFile__ })
- return ""
+ return (handle_ { haType__ = ClosedHandle,
+ haFO__ = nullFile__ },
+ "")
_ -> do
more <- unsafeInterleaveIO (lazyReadBlock handle fo)
stToIO (unpackNBytesAccST buf bytes more)
-1 -> -- an error occurred, close the handle
withHandle handle $ \ handle_ -> do
CCALL(closeFile) (haFO__ handle_) (0::Int){- don't bother flushing-} -- ConcHask: SAFE, won't block
- writeHandle handle (handle_ { haType__ = ClosedHandle,
- haFO__ = nullFile__ })
- return ""
+ return (handle_ { haType__ = ClosedHandle,
+ haFO__ = nullFile__ },
+ "")
_ -> do
more <- unsafeInterleaveIO (lazyReadLine handle fo)
buf <- CCALL(getBufStart) fo bytes -- ConcHask: won't block
-1 -> -- error, silently close handle.
withHandle handle $ \ handle_ -> do
CCALL(closeFile) (haFO__ handle_) (0::Int){-don't bother flusing-} -- ConcHask: SAFE, won't block
- writeHandle handle (handle_{ haType__ = ClosedHandle,
- haFO__ = nullFile__ })
- return ""
+ return (handle_{ haType__ = ClosedHandle,
+ haFO__ = nullFile__ },
+ "")
_ -> do
more <- unsafeInterleaveIO (lazyReadChar handle fo)
return (chr char : more)
hPutChar handle c =
wantWriteableHandle "hPutChar" handle $ \ handle_ -> do
let fo = haFO__ handle_
+ flushConnectedBuf fo
rc <- mayBlock fo (CCALL(filePutc) fo c) -- ConcHask: UNSAFE, may block.
- writeHandle handle handle_
if rc == 0
then return ()
else constructErrorAndFail "hPutChar"
hPutStr handle str =
wantWriteableHandle "hPutStr" handle $ \ handle_ -> do
let fo = haFO__ handle_
+ flushConnectedBuf fo
case haBufferMode__ handle_ of
LineBuffering -> do
buf <- CCALL(getWriteableBuf) fo
writeBlocks fo buf bsz pos str
NoBuffering -> do
writeChars fo str
- writeHandle handle handle_
-
\end{code}
Going across the border between Haskell and C is relatively costly,
projects / ghc-hetmet.git / blobdiff