1 {-# OPTIONS -fno-implicit-prelude -#include "HsBase.h" #-}
6 -----------------------------------------------------------------------------
9 -- Copyright : (c) The University of Glasgow, 1994-2001
10 -- License : see libraries/base/LICENSE
12 -- Maintainer : libraries@haskell.org
13 -- Stability : internal
14 -- Portability : non-portable
16 -- This module defines the basic operations on I\/O \"handles\".
18 -----------------------------------------------------------------------------
21 withHandle, withHandle', withHandle_,
22 wantWritableHandle, wantReadableHandle, wantSeekableHandle,
24 newEmptyBuffer, allocateBuffer, readCharFromBuffer, writeCharIntoBuffer,
25 flushWriteBufferOnly, flushWriteBuffer, flushReadBuffer,
26 fillReadBuffer, fillReadBufferWithoutBlocking,
27 readRawBuffer, readRawBufferPtr,
28 writeRawBuffer, writeRawBufferPtr,
30 #ifndef mingw32_TARGET_OS
34 ioe_closedHandle, ioe_EOF, ioe_notReadable, ioe_notWritable,
36 stdin, stdout, stderr,
37 IOMode(..), openFile, openBinaryFile, openTempFile, openBinaryTempFile, openFd, fdToHandle,
38 hFileSize, hSetFileSize, hIsEOF, isEOF, hLookAhead, hSetBuffering, hSetBinaryMode,
39 hFlush, hDuplicate, hDuplicateTo,
43 HandlePosition, HandlePosn(..), hGetPosn, hSetPosn,
44 SeekMode(..), hSeek, hTell,
46 hIsOpen, hIsClosed, hIsReadable, hIsWritable, hGetBuffering, hIsSeekable,
47 hSetEcho, hGetEcho, hIsTerminalDevice,
57 #include "ghcconfig.h"
64 import System.IO.Error
65 import System.Posix.Internals
66 import System.FilePath
72 import GHC.Read ( Read )
77 import GHC.Num ( Integer(..), Num(..) )
79 import GHC.Real ( toInteger )
83 -- -----------------------------------------------------------------------------
86 -- hWaitForInput blocks (should use a timeout)
88 -- unbuffered hGetLine is a bit dodgy
90 -- hSetBuffering: can't change buffering on a stream,
91 -- when the read buffer is non-empty? (no way to flush the buffer)
93 -- ---------------------------------------------------------------------------
94 -- Are files opened by default in text or binary mode, if the user doesn't
97 dEFAULT_OPEN_IN_BINARY_MODE = False :: Bool
99 -- ---------------------------------------------------------------------------
100 -- Creating a new handle
102 newFileHandle :: FilePath -> (MVar Handle__ -> IO ()) -> Handle__ -> IO Handle
103 newFileHandle filepath finalizer hc = do
105 addMVarFinalizer m (finalizer m)
106 return (FileHandle filepath m)
108 -- ---------------------------------------------------------------------------
109 -- Working with Handles
112 In the concurrent world, handles are locked during use. This is done
113 by wrapping an MVar around the handle which acts as a mutex over
114 operations on the handle.
116 To avoid races, we use the following bracketing operations. The idea
117 is to obtain the lock, do some operation and replace the lock again,
118 whether the operation succeeded or failed. We also want to handle the
119 case where the thread receives an exception while processing the IO
120 operation: in these cases we also want to relinquish the lock.
122 There are three versions of @withHandle@: corresponding to the three
123 possible combinations of:
125 - the operation may side-effect the handle
126 - the operation may return a result
128 If the operation generates an error or an exception is raised, the
129 original handle is always replaced [ this is the case at the moment,
130 but we might want to revisit this in the future --SDM ].
133 {-# INLINE withHandle #-}
134 withHandle :: String -> Handle -> (Handle__ -> IO (Handle__,a)) -> IO a
135 withHandle fun h@(FileHandle _ m) act = withHandle' fun h m act
136 withHandle fun h@(DuplexHandle _ m _) act = withHandle' fun h m act
138 withHandle' :: String -> Handle -> MVar Handle__
139 -> (Handle__ -> IO (Handle__,a)) -> IO a
140 withHandle' fun h m act =
143 checkBufferInvariants h_
144 (h',v) <- catchException (act h_)
145 (\ err -> putMVar m h_ >>
147 IOException ex -> ioError (augmentIOError ex fun h)
149 checkBufferInvariants h'
153 {-# INLINE withHandle_ #-}
154 withHandle_ :: String -> Handle -> (Handle__ -> IO a) -> IO a
155 withHandle_ fun h@(FileHandle _ m) act = withHandle_' fun h m act
156 withHandle_ fun h@(DuplexHandle _ m _) act = withHandle_' fun h m act
158 withHandle_' fun h m act =
161 checkBufferInvariants h_
162 v <- catchException (act h_)
163 (\ err -> putMVar m h_ >>
165 IOException ex -> ioError (augmentIOError ex fun h)
167 checkBufferInvariants h_
171 withAllHandles__ :: String -> Handle -> (Handle__ -> IO Handle__) -> IO ()
172 withAllHandles__ fun h@(FileHandle _ m) act = withHandle__' fun h m act
173 withAllHandles__ fun h@(DuplexHandle _ r w) act = do
174 withHandle__' fun h r act
175 withHandle__' fun h w act
177 withHandle__' fun h m act =
180 checkBufferInvariants h_
181 h' <- catchException (act h_)
182 (\ err -> putMVar m h_ >>
184 IOException ex -> ioError (augmentIOError ex fun h)
186 checkBufferInvariants h'
190 augmentIOError (IOError _ iot _ str fp) fun h
191 = IOError (Just h) iot fun str filepath
194 | otherwise = case h of
195 FileHandle fp _ -> Just fp
196 DuplexHandle fp _ _ -> Just fp
198 -- ---------------------------------------------------------------------------
199 -- Wrapper for write operations.
201 wantWritableHandle :: String -> Handle -> (Handle__ -> IO a) -> IO a
202 wantWritableHandle fun h@(FileHandle _ m) act
203 = wantWritableHandle' fun h m act
204 wantWritableHandle fun h@(DuplexHandle _ _ m) act
205 = wantWritableHandle' fun h m act
206 -- ToDo: in the Duplex case, we don't need to checkWritableHandle
209 :: String -> Handle -> MVar Handle__
210 -> (Handle__ -> IO a) -> IO a
211 wantWritableHandle' fun h m act
212 = withHandle_' fun h m (checkWritableHandle act)
214 checkWritableHandle act handle_
215 = case haType handle_ of
216 ClosedHandle -> ioe_closedHandle
217 SemiClosedHandle -> ioe_closedHandle
218 ReadHandle -> ioe_notWritable
219 ReadWriteHandle -> do
220 let ref = haBuffer handle_
223 if not (bufferIsWritable buf)
224 then do b <- flushReadBuffer (haFD handle_) buf
225 return b{ bufState=WriteBuffer }
227 writeIORef ref new_buf
229 _other -> act handle_
231 -- ---------------------------------------------------------------------------
232 -- Wrapper for read operations.
234 wantReadableHandle :: String -> Handle -> (Handle__ -> IO a) -> IO a
235 wantReadableHandle fun h@(FileHandle _ m) act
236 = wantReadableHandle' fun h m act
237 wantReadableHandle fun h@(DuplexHandle _ m _) act
238 = wantReadableHandle' fun h m act
239 -- ToDo: in the Duplex case, we don't need to checkReadableHandle
242 :: String -> Handle -> MVar Handle__
243 -> (Handle__ -> IO a) -> IO a
244 wantReadableHandle' fun h m act
245 = withHandle_' fun h m (checkReadableHandle act)
247 checkReadableHandle act handle_ =
248 case haType handle_ of
249 ClosedHandle -> ioe_closedHandle
250 SemiClosedHandle -> ioe_closedHandle
251 AppendHandle -> ioe_notReadable
252 WriteHandle -> ioe_notReadable
253 ReadWriteHandle -> do
254 let ref = haBuffer handle_
256 when (bufferIsWritable buf) $ do
257 new_buf <- flushWriteBuffer (haFD handle_) (haIsStream handle_) buf
258 writeIORef ref new_buf{ bufState=ReadBuffer }
260 _other -> act handle_
262 -- ---------------------------------------------------------------------------
263 -- Wrapper for seek operations.
265 wantSeekableHandle :: String -> Handle -> (Handle__ -> IO a) -> IO a
266 wantSeekableHandle fun h@(DuplexHandle _ _ _) _act =
267 ioException (IOError (Just h) IllegalOperation fun
268 "handle is not seekable" Nothing)
269 wantSeekableHandle fun h@(FileHandle _ m) act =
270 withHandle_' fun h m (checkSeekableHandle act)
272 checkSeekableHandle act handle_ =
273 case haType handle_ of
274 ClosedHandle -> ioe_closedHandle
275 SemiClosedHandle -> ioe_closedHandle
276 AppendHandle -> ioe_notSeekable
277 _ | haIsBin handle_ || tEXT_MODE_SEEK_ALLOWED -> act handle_
278 | otherwise -> ioe_notSeekable_notBin
280 -- -----------------------------------------------------------------------------
283 ioe_closedHandle, ioe_EOF,
284 ioe_notReadable, ioe_notWritable,
285 ioe_notSeekable, ioe_notSeekable_notBin :: IO a
287 ioe_closedHandle = ioException
288 (IOError Nothing IllegalOperation ""
289 "handle is closed" Nothing)
290 ioe_EOF = ioException
291 (IOError Nothing EOF "" "" Nothing)
292 ioe_notReadable = ioException
293 (IOError Nothing IllegalOperation ""
294 "handle is not open for reading" Nothing)
295 ioe_notWritable = ioException
296 (IOError Nothing IllegalOperation ""
297 "handle is not open for writing" Nothing)
298 ioe_notSeekable = ioException
299 (IOError Nothing IllegalOperation ""
300 "handle is not seekable" Nothing)
301 ioe_notSeekable_notBin = ioException
302 (IOError Nothing IllegalOperation ""
303 "seek operations on text-mode handles are not allowed on this platform"
306 ioe_finalizedHandle fp = throw (IOException
307 (IOError Nothing IllegalOperation ""
308 "handle is finalized" (Just fp)))
310 ioe_bufsiz :: Int -> IO a
311 ioe_bufsiz n = ioException
312 (IOError Nothing InvalidArgument "hSetBuffering"
313 ("illegal buffer size " ++ showsPrec 9 n []) Nothing)
314 -- 9 => should be parens'ified.
316 -- -----------------------------------------------------------------------------
319 -- For a duplex handle, we arrange that the read side points to the write side
320 -- (and hence keeps it alive if the read side is alive). This is done by
321 -- having the haOtherSide field of the read side point to the read side.
322 -- The finalizer is then placed on the write side, and the handle only gets
323 -- finalized once, when both sides are no longer required.
325 -- NOTE about finalized handles: It's possible that a handle can be
326 -- finalized and then we try to use it later, for example if the
327 -- handle is referenced from another finalizer, or from a thread that
328 -- has become unreferenced and then resurrected (arguably in the
329 -- latter case we shouldn't finalize the Handle...). Anyway,
330 -- we try to emit a helpful message which is better than nothing.
332 stdHandleFinalizer :: FilePath -> MVar Handle__ -> IO ()
333 stdHandleFinalizer fp m = do
335 flushWriteBufferOnly h_
336 putMVar m (ioe_finalizedHandle fp)
338 handleFinalizer :: FilePath -> MVar Handle__ -> IO ()
339 handleFinalizer fp m = do
340 handle_ <- takeMVar m
341 case haType handle_ of
342 ClosedHandle -> return ()
343 _ -> do flushWriteBufferOnly handle_ `catchException` \_ -> return ()
344 -- ignore errors and async exceptions, and close the
345 -- descriptor anyway...
346 hClose_handle_ handle_
348 putMVar m (ioe_finalizedHandle fp)
350 -- ---------------------------------------------------------------------------
351 -- Grimy buffer operations
354 checkBufferInvariants h_ = do
355 let ref = haBuffer h_
356 Buffer{ bufWPtr=w, bufRPtr=r, bufSize=size, bufState=state } <- readIORef ref
361 && ( r /= w || (r == 0 && w == 0) )
362 && ( state /= WriteBuffer || r == 0 )
363 && ( state /= WriteBuffer || w < size ) -- write buffer is never full
365 then error "buffer invariant violation"
368 checkBufferInvariants h_ = return ()
371 newEmptyBuffer :: RawBuffer -> BufferState -> Int -> Buffer
372 newEmptyBuffer b state size
373 = Buffer{ bufBuf=b, bufRPtr=0, bufWPtr=0, bufSize=size, bufState=state }
375 allocateBuffer :: Int -> BufferState -> IO Buffer
376 allocateBuffer sz@(I# size) state = IO $ \s ->
377 #ifdef mingw32_TARGET_OS
378 -- To implement asynchronous I/O under Win32, we have to pass
379 -- buffer references to external threads that handles the
380 -- filling/emptying of their contents. Hence, the buffer cannot
381 -- be moved around by the GC.
382 case newPinnedByteArray# size s of { (# s, b #) ->
384 case newByteArray# size s of { (# s, b #) ->
386 (# s, newEmptyBuffer b state sz #) }
388 writeCharIntoBuffer :: RawBuffer -> Int -> Char -> IO Int
389 writeCharIntoBuffer slab (I# off) (C# c)
390 = IO $ \s -> case writeCharArray# slab off c s of
391 s -> (# s, I# (off +# 1#) #)
393 readCharFromBuffer :: RawBuffer -> Int -> IO (Char, Int)
394 readCharFromBuffer slab (I# off)
395 = IO $ \s -> case readCharArray# slab off s of
396 (# s, c #) -> (# s, (C# c, I# (off +# 1#)) #)
398 getBuffer :: FD -> BufferState -> IO (IORef Buffer, BufferMode)
399 getBuffer fd state = do
400 buffer <- allocateBuffer dEFAULT_BUFFER_SIZE state
401 ioref <- newIORef buffer
405 | is_tty = LineBuffering
406 | otherwise = BlockBuffering Nothing
408 return (ioref, buffer_mode)
410 mkUnBuffer :: IO (IORef Buffer)
412 buffer <- allocateBuffer 1 ReadBuffer
415 -- flushWriteBufferOnly flushes the buffer iff it contains pending write data.
416 flushWriteBufferOnly :: Handle__ -> IO ()
417 flushWriteBufferOnly h_ = do
421 new_buf <- if bufferIsWritable buf
422 then flushWriteBuffer fd (haIsStream h_) buf
424 writeIORef ref new_buf
426 -- flushBuffer syncs the file with the buffer, including moving the
427 -- file pointer backwards in the case of a read buffer.
428 flushBuffer :: Handle__ -> IO ()
430 let ref = haBuffer h_
435 ReadBuffer -> flushReadBuffer (haFD h_) buf
436 WriteBuffer -> flushWriteBuffer (haFD h_) (haIsStream h_) buf
438 writeIORef ref flushed_buf
440 -- When flushing a read buffer, we seek backwards by the number of
441 -- characters in the buffer. The file descriptor must therefore be
442 -- seekable: attempting to flush the read buffer on an unseekable
443 -- handle is not allowed.
445 flushReadBuffer :: FD -> Buffer -> IO Buffer
446 flushReadBuffer fd buf
447 | bufferEmpty buf = return buf
449 let off = negate (bufWPtr buf - bufRPtr buf)
451 puts ("flushReadBuffer: new file offset = " ++ show off ++ "\n")
453 throwErrnoIfMinus1Retry "flushReadBuffer"
454 (c_lseek (fromIntegral fd) (fromIntegral off) sEEK_CUR)
455 return buf{ bufWPtr=0, bufRPtr=0 }
457 flushWriteBuffer :: FD -> Bool -> Buffer -> IO Buffer
458 flushWriteBuffer fd is_stream buf@Buffer{ bufBuf=b, bufRPtr=r, bufWPtr=w } =
459 seq fd $ do -- strictness hack
462 puts ("flushWriteBuffer, fd=" ++ show fd ++ ", bytes=" ++ show bytes ++ "\n")
465 then return (buf{ bufRPtr=0, bufWPtr=0 })
467 res <- writeRawBuffer "flushWriteBuffer" (fromIntegral fd) is_stream b
468 (fromIntegral r) (fromIntegral bytes)
469 let res' = fromIntegral res
471 then flushWriteBuffer fd is_stream (buf{ bufRPtr = r + res' })
472 else return buf{ bufRPtr=0, bufWPtr=0 }
474 fillReadBuffer :: FD -> Bool -> Bool -> Buffer -> IO Buffer
475 fillReadBuffer fd is_line is_stream
476 buf@Buffer{ bufBuf=b, bufRPtr=r, bufWPtr=w, bufSize=size } =
477 -- buffer better be empty:
478 assert (r == 0 && w == 0) $ do
479 fillReadBufferLoop fd is_line is_stream buf b w size
481 -- For a line buffer, we just get the first chunk of data to arrive,
482 -- and don't wait for the whole buffer to be full (but we *do* wait
483 -- until some data arrives). This isn't really line buffering, but it
484 -- appears to be what GHC has done for a long time, and I suspect it
485 -- is more useful than line buffering in most cases.
487 fillReadBufferLoop fd is_line is_stream buf b w size = do
489 if bytes == 0 -- buffer full?
490 then return buf{ bufRPtr=0, bufWPtr=w }
493 puts ("fillReadBufferLoop: bytes = " ++ show bytes ++ "\n")
495 res <- readRawBuffer "fillReadBuffer" fd is_stream b
496 (fromIntegral w) (fromIntegral bytes)
497 let res' = fromIntegral res
499 puts ("fillReadBufferLoop: res' = " ++ show res' ++ "\n")
504 else return buf{ bufRPtr=0, bufWPtr=w }
505 else if res' < bytes && not is_line
506 then fillReadBufferLoop fd is_line is_stream buf b (w+res') size
507 else return buf{ bufRPtr=0, bufWPtr=w+res' }
510 fillReadBufferWithoutBlocking :: FD -> Bool -> Buffer -> IO Buffer
511 fillReadBufferWithoutBlocking fd is_stream
512 buf@Buffer{ bufBuf=b, bufRPtr=r, bufWPtr=w, bufSize=size } =
513 -- buffer better be empty:
514 assert (r == 0 && w == 0) $ do
516 puts ("fillReadBufferLoopNoBlock: bytes = " ++ show bytes ++ "\n")
518 res <- readRawBufferNoBlock "fillReadBuffer" fd is_stream b
519 0 (fromIntegral size)
520 let res' = fromIntegral res
522 puts ("fillReadBufferLoopNoBlock: res' = " ++ show res' ++ "\n")
524 return buf{ bufRPtr=0, bufWPtr=res' }
526 -- Low level routines for reading/writing to (raw)buffers:
528 #ifndef mingw32_TARGET_OS
529 readRawBuffer :: String -> FD -> Bool -> RawBuffer -> Int -> CInt -> IO CInt
530 readRawBuffer loc fd is_stream buf off len =
531 throwErrnoIfMinus1RetryMayBlock loc
532 (read_rawBuffer fd buf off len)
533 (threadWaitRead (fromIntegral fd))
535 readRawBufferNoBlock :: String -> FD -> Bool -> RawBuffer -> Int -> CInt -> IO CInt
536 readRawBufferNoBlock loc fd is_stream buf off len =
537 throwErrnoIfMinus1RetryOnBlock loc
538 (read_rawBuffer fd buf off len)
541 readRawBufferPtr :: String -> FD -> Bool -> Ptr CChar -> Int -> CInt -> IO CInt
542 readRawBufferPtr loc fd is_stream buf off len =
543 throwErrnoIfMinus1RetryMayBlock loc
544 (read_off fd buf off len)
545 (threadWaitRead (fromIntegral fd))
547 writeRawBuffer :: String -> FD -> Bool -> RawBuffer -> Int -> CInt -> IO CInt
548 writeRawBuffer loc fd is_stream buf off len =
549 throwErrnoIfMinus1RetryMayBlock loc
550 (write_rawBuffer (fromIntegral fd) buf off len)
551 (threadWaitWrite (fromIntegral fd))
553 writeRawBufferPtr :: String -> FD -> Bool -> Ptr CChar -> Int -> CInt -> IO CInt
554 writeRawBufferPtr loc fd is_stream buf off len =
555 throwErrnoIfMinus1RetryMayBlock loc
556 (write_off (fromIntegral fd) buf off len)
557 (threadWaitWrite (fromIntegral fd))
559 foreign import ccall unsafe "__hscore_PrelHandle_read"
560 read_rawBuffer :: FD -> RawBuffer -> Int -> CInt -> IO CInt
562 foreign import ccall unsafe "__hscore_PrelHandle_read"
563 read_off :: FD -> Ptr CChar -> Int -> CInt -> IO CInt
565 foreign import ccall unsafe "__hscore_PrelHandle_write"
566 write_rawBuffer :: CInt -> RawBuffer -> Int -> CInt -> IO CInt
568 foreign import ccall unsafe "__hscore_PrelHandle_write"
569 write_off :: CInt -> Ptr CChar -> Int -> CInt -> IO CInt
571 #else /* mingw32_TARGET_OS.... */
573 readRawBuffer :: String -> FD -> Bool -> RawBuffer -> Int -> CInt -> IO CInt
574 readRawBuffer loc fd is_stream buf off len
575 | threaded = blockingReadRawBuffer loc fd is_stream buf off len
576 | otherwise = asyncReadRawBuffer loc fd is_stream buf off len
578 readRawBufferPtr :: String -> FD -> Bool -> Ptr CChar -> Int -> CInt -> IO CInt
579 readRawBufferPtr loc fd is_stream buf off len
580 | threaded = blockingReadRawBufferPtr loc fd is_stream buf off len
581 | otherwise = asyncReadRawBufferPtr loc fd is_stream buf off len
583 writeRawBuffer :: String -> FD -> Bool -> RawBuffer -> Int -> CInt -> IO CInt
584 writeRawBuffer loc fd is_stream buf off len
585 | threaded = blockingWriteRawBuffer loc fd is_stream buf off len
586 | otherwise = asyncWriteRawBuffer loc fd is_stream buf off len
588 writeRawBufferPtr :: String -> FD -> Bool -> Ptr CChar -> Int -> CInt -> IO CInt
589 writeRawBufferPtr loc fd is_stream buf off len
590 | threaded = blockingWriteRawBufferPtr loc fd is_stream buf off len
591 | otherwise = asyncWriteRawBufferPtr loc fd is_stream buf off len
593 -- ToDo: we don't have a non-blocking primitve read on Win32
594 readRawBufferNoBlock :: String -> FD -> Bool -> RawBuffer -> Int -> CInt -> IO CInt
595 readRawBufferNoBlock = readRawBufferNoBlock
597 -- Async versions of the read/write primitives, for the non-threaded RTS
599 asyncReadRawBuffer loc fd is_stream buf off len = do
600 (l, rc) <- asyncReadBA fd (if is_stream then 1 else 0)
601 (fromIntegral len) off buf
604 ioError (errnoToIOError loc (Errno (fromIntegral rc)) Nothing Nothing)
605 else return (fromIntegral l)
607 asyncReadRawBufferPtr loc fd is_stream buf off len = do
608 (l, rc) <- asyncRead fd (if is_stream then 1 else 0)
609 (fromIntegral len) (buf `plusPtr` off)
612 ioError (errnoToIOError loc (Errno (fromIntegral rc)) Nothing Nothing)
613 else return (fromIntegral l)
615 asyncWriteRawBuffer loc fd is_stream buf off len = do
616 (l, rc) <- asyncWriteBA fd (if is_stream then 1 else 0)
617 (fromIntegral len) off buf
620 ioError (errnoToIOError loc (Errno (fromIntegral rc)) Nothing Nothing)
621 else return (fromIntegral l)
623 asyncWriteRawBufferPtr loc fd is_stream buf off len = do
624 (l, rc) <- asyncWrite fd (if is_stream then 1 else 0)
625 (fromIntegral len) (buf `plusPtr` off)
628 ioError (errnoToIOError loc (Errno (fromIntegral rc)) Nothing Nothing)
629 else return (fromIntegral l)
631 -- Blocking versions of the read/write primitives, for the threaded RTS
633 blockingReadRawBuffer loc fd True buf off len =
634 throwErrnoIfMinus1Retry loc $
635 recv_rawBuffer fd buf off len
636 blockingReadRawBuffer loc fd False buf off len =
637 throwErrnoIfMinus1Retry loc $
638 read_rawBuffer fd buf off len
640 blockingReadRawBufferPtr loc fd True buf off len =
641 throwErrnoIfMinus1Retry loc $
642 recv_off fd buf off len
643 blockingReadRawBufferPtr loc fd False buf off len =
644 throwErrnoIfMinus1Retry loc $
645 read_off fd buf off len
647 blockingWriteRawBuffer loc fd True buf off len =
648 throwErrnoIfMinus1Retry loc $
649 send_rawBuffer (fromIntegral fd) buf off len
650 blockingWriteRawBuffer loc fd False buf off len =
651 throwErrnoIfMinus1Retry loc $
652 write_rawBuffer (fromIntegral fd) buf off len
654 blockingWriteRawBufferPtr loc fd True buf off len =
655 throwErrnoIfMinus1Retry loc $
656 send_off (fromIntegral fd) buf off len
657 blockingWriteRawBufferPtr loc fd False buf off len =
658 throwErrnoIfMinus1Retry loc $
659 write_off (fromIntegral fd) buf off len
661 -- NOTE: "safe" versions of the read/write calls for use by the threaded RTS.
662 -- These calls may block, but that's ok.
664 foreign import ccall safe "__hscore_PrelHandle_read"
665 read_rawBuffer :: FD -> RawBuffer -> Int -> CInt -> IO CInt
667 foreign import ccall safe "__hscore_PrelHandle_read"
668 read_off :: FD -> Ptr CChar -> Int -> CInt -> IO CInt
670 foreign import ccall safe "__hscore_PrelHandle_write"
671 write_rawBuffer :: CInt -> RawBuffer -> Int -> CInt -> IO CInt
673 foreign import ccall safe "__hscore_PrelHandle_write"
674 write_off :: CInt -> Ptr CChar -> Int -> CInt -> IO CInt
676 foreign import ccall safe "__hscore_PrelHandle_recv"
677 recv_rawBuffer :: FD -> RawBuffer -> Int -> CInt -> IO CInt
679 foreign import ccall safe "__hscore_PrelHandle_recv"
680 recv_off :: FD -> Ptr CChar -> Int -> CInt -> IO CInt
682 foreign import ccall safe "__hscore_PrelHandle_send"
683 send_rawBuffer :: CInt -> RawBuffer -> Int -> CInt -> IO CInt
685 foreign import ccall safe "__hscore_PrelHandle_send"
686 send_off :: CInt -> Ptr CChar -> Int -> CInt -> IO CInt
688 foreign import ccall "rtsSupportsBoundThreads" threaded :: Bool
691 -- ---------------------------------------------------------------------------
694 -- Three handles are allocated during program initialisation. The first
695 -- two manage input or output from the Haskell program's standard input
696 -- or output channel respectively. The third manages output to the
697 -- standard error channel. These handles are initially open.
703 -- | A handle managing input from the Haskell program's standard input channel.
705 stdin = unsafePerformIO $ do
706 -- ToDo: acquire lock
707 setNonBlockingFD fd_stdin
708 (buf, bmode) <- getBuffer fd_stdin ReadBuffer
709 mkStdHandle fd_stdin "<stdin>" ReadHandle buf bmode
711 -- | A handle managing output to the Haskell program's standard output channel.
713 stdout = unsafePerformIO $ do
714 -- ToDo: acquire lock
715 -- We don't set non-blocking mode on stdout or sterr, because
716 -- some shells don't recover properly.
717 -- setNonBlockingFD fd_stdout
718 (buf, bmode) <- getBuffer fd_stdout WriteBuffer
719 mkStdHandle fd_stdout "<stdout>" WriteHandle buf bmode
721 -- | A handle managing output to the Haskell program's standard error channel.
723 stderr = unsafePerformIO $ do
724 -- ToDo: acquire lock
725 -- We don't set non-blocking mode on stdout or sterr, because
726 -- some shells don't recover properly.
727 -- setNonBlockingFD fd_stderr
729 mkStdHandle fd_stderr "<stderr>" WriteHandle buf NoBuffering
731 -- ---------------------------------------------------------------------------
732 -- Opening and Closing Files
734 addFilePathToIOError fun fp (IOError h iot _ str _)
735 = IOError h iot fun str (Just fp)
737 -- | Computation 'openFile' @file mode@ allocates and returns a new, open
738 -- handle to manage the file @file@. It manages input if @mode@
739 -- is 'ReadMode', output if @mode@ is 'WriteMode' or 'AppendMode',
740 -- and both input and output if mode is 'ReadWriteMode'.
742 -- If the file does not exist and it is opened for output, it should be
743 -- created as a new file. If @mode@ is 'WriteMode' and the file
744 -- already exists, then it should be truncated to zero length.
745 -- Some operating systems delete empty files, so there is no guarantee
746 -- that the file will exist following an 'openFile' with @mode@
747 -- 'WriteMode' unless it is subsequently written to successfully.
748 -- The handle is positioned at the end of the file if @mode@ is
749 -- 'AppendMode', and otherwise at the beginning (in which case its
750 -- internal position is 0).
751 -- The initial buffer mode is implementation-dependent.
753 -- This operation may fail with:
755 -- * 'isAlreadyInUseError' if the file is already open and cannot be reopened;
757 -- * 'isDoesNotExistError' if the file does not exist; or
759 -- * 'isPermissionError' if the user does not have permission to open the file.
761 -- Note: if you will be working with files containing binary data, you'll want to
762 -- be using 'openBinaryFile'.
763 openFile :: FilePath -> IOMode -> IO Handle
766 (openFile' fp im dEFAULT_OPEN_IN_BINARY_MODE)
767 (\e -> ioError (addFilePathToIOError "openFile" fp e))
769 -- | Like 'openFile', but open the file in binary mode.
770 -- On Windows, reading a file in text mode (which is the default)
771 -- will translate CRLF to LF, and writing will translate LF to CRLF.
772 -- This is usually what you want with text files. With binary files
773 -- this is undesirable; also, as usual under Microsoft operating systems,
774 -- text mode treats control-Z as EOF. Binary mode turns off all special
775 -- treatment of end-of-line and end-of-file characters.
776 -- (See also 'hSetBinaryMode'.)
778 openBinaryFile :: FilePath -> IOMode -> IO Handle
779 openBinaryFile fp m =
781 (openFile' fp m True)
782 (\e -> ioError (addFilePathToIOError "openBinaryFile" fp e))
784 openFile' filepath mode binary =
785 withCString filepath $ \ f ->
788 oflags1 = case mode of
789 ReadMode -> read_flags
790 WriteMode -> write_flags
791 ReadWriteMode -> rw_flags
792 AppendMode -> append_flags
798 oflags = oflags1 .|. binary_flags
801 -- the old implementation had a complicated series of three opens,
802 -- which is perhaps because we have to be careful not to open
803 -- directories. However, the man pages I've read say that open()
804 -- always returns EISDIR if the file is a directory and was opened
805 -- for writing, so I think we're ok with a single open() here...
806 fd <- fromIntegral `liftM`
807 throwErrnoIfMinus1Retry "openFile"
808 (c_open f (fromIntegral oflags) 0o666)
810 openFd fd Nothing False filepath mode binary
811 `catchException` \e -> do c_close (fromIntegral fd); throw e
812 -- NB. don't forget to close the FD if openFd fails, otherwise
814 -- ASSERT: if we just created the file, then openFd won't fail
815 -- (so we don't need to worry about removing the newly created file
816 -- in the event of an error).
818 -- | The function creates a temporary file in ReadWrite mode.
819 -- The created file isn\'t deleted automatically, so you need to delete it manually.
820 openTempFile :: FilePath -- ^ Directory in which to create the file
821 -> String -- ^ File name template. If the template is \"foo.ext\" then
822 -- the create file will be \"fooXXX.ext\" where XXX is some
824 -> IO (FilePath, Handle)
825 openTempFile tmp_dir template = openTempFile' "openTempFile" tmp_dir template dEFAULT_OPEN_IN_BINARY_MODE
827 -- | Like 'openTempFile', but opens the file in binary mode. See 'openBinaryFile' for more comments.
828 openBinaryTempFile :: FilePath -> String -> IO (FilePath, Handle)
829 openBinaryTempFile tmp_dir template = openTempFile' "openBinaryTempFile" tmp_dir template True
831 openTempFile' :: String -> FilePath -> String -> Bool -> IO (FilePath, Handle)
832 openTempFile' loc tmp_dir template binary = do
836 (prefix,suffix) = break (=='.') template
838 oflags1 = rw_flags .|. o_EXCL
844 oflags = oflags1 .|. binary_flags
847 fd <- withCString filepath $ \ f ->
848 c_open f oflags 0o666
853 then findTempName (x+1)
854 else ioError (errnoToIOError loc errno Nothing (Just tmp_dir))
856 h <- openFd (fromIntegral fd) Nothing False filepath ReadWriteMode True
857 `catchException` \e -> do c_close (fromIntegral fd); throw e
860 filename = prefix ++ show x ++ suffix
861 filepath = tmp_dir `joinFileName` filename
864 std_flags = o_NONBLOCK .|. o_NOCTTY
865 output_flags = std_flags .|. o_CREAT
866 read_flags = std_flags .|. o_RDONLY
867 write_flags = output_flags .|. o_WRONLY .|. o_TRUNC
868 rw_flags = output_flags .|. o_RDWR
869 append_flags = write_flags .|. o_APPEND
871 -- ---------------------------------------------------------------------------
874 openFd :: FD -> Maybe FDType -> Bool -> FilePath -> IOMode -> Bool -> IO Handle
875 openFd fd mb_fd_type is_socket filepath mode binary = do
876 -- turn on non-blocking mode
879 let (ha_type, write) =
881 ReadMode -> ( ReadHandle, False )
882 WriteMode -> ( WriteHandle, True )
883 ReadWriteMode -> ( ReadWriteHandle, True )
884 AppendMode -> ( AppendHandle, True )
886 -- open() won't tell us if it was a directory if we only opened for
887 -- reading, so check again.
895 ioException (IOError Nothing InappropriateType "openFile"
896 "is a directory" Nothing)
899 | ReadWriteHandle <- ha_type -> mkDuplexHandle fd is_socket filepath binary
900 | otherwise -> mkFileHandle fd is_socket filepath ha_type binary
902 -- regular files need to be locked
904 #ifndef mingw32_TARGET_OS
905 r <- lockFile (fromIntegral fd) (fromBool write) 1{-exclusive-}
907 ioException (IOError Nothing ResourceBusy "openFile"
908 "file is locked" Nothing)
910 mkFileHandle fd is_socket filepath ha_type binary
913 fdToHandle :: FD -> IO Handle
916 let fd_str = "<file descriptor: " ++ show fd ++ ">"
917 openFd fd Nothing False{-XXX!-} fd_str mode True{-bin mode-}
920 #ifndef mingw32_TARGET_OS
921 foreign import ccall unsafe "lockFile"
922 lockFile :: CInt -> CInt -> CInt -> IO CInt
924 foreign import ccall unsafe "unlockFile"
925 unlockFile :: CInt -> IO CInt
928 mkStdHandle :: FD -> FilePath -> HandleType -> IORef Buffer -> BufferMode
930 mkStdHandle fd filepath ha_type buf bmode = do
931 spares <- newIORef BufferListNil
932 newFileHandle filepath (stdHandleFinalizer filepath)
933 (Handle__ { haFD = fd,
935 haIsBin = dEFAULT_OPEN_IN_BINARY_MODE,
937 haBufferMode = bmode,
940 haOtherSide = Nothing
943 mkFileHandle :: FD -> Bool -> FilePath -> HandleType -> Bool -> IO Handle
944 mkFileHandle fd is_stream filepath ha_type binary = do
945 (buf, bmode) <- getBuffer fd (initBufferState ha_type)
946 spares <- newIORef BufferListNil
947 newFileHandle filepath (handleFinalizer filepath)
948 (Handle__ { haFD = fd,
951 haIsStream = is_stream,
952 haBufferMode = bmode,
955 haOtherSide = Nothing
958 mkDuplexHandle :: FD -> Bool -> FilePath -> Bool -> IO Handle
959 mkDuplexHandle fd is_stream filepath binary = do
960 (w_buf, w_bmode) <- getBuffer fd WriteBuffer
961 w_spares <- newIORef BufferListNil
963 Handle__ { haFD = fd,
964 haType = WriteHandle,
966 haIsStream = is_stream,
967 haBufferMode = w_bmode,
969 haBuffers = w_spares,
970 haOtherSide = Nothing
972 write_side <- newMVar w_handle_
974 (r_buf, r_bmode) <- getBuffer fd ReadBuffer
975 r_spares <- newIORef BufferListNil
977 Handle__ { haFD = fd,
980 haIsStream = is_stream,
981 haBufferMode = r_bmode,
983 haBuffers = r_spares,
984 haOtherSide = Just write_side
986 read_side <- newMVar r_handle_
988 addMVarFinalizer write_side (handleFinalizer filepath write_side)
989 return (DuplexHandle filepath read_side write_side)
992 initBufferState ReadHandle = ReadBuffer
993 initBufferState _ = WriteBuffer
995 -- ---------------------------------------------------------------------------
998 -- | Computation 'hClose' @hdl@ makes handle @hdl@ closed. Before the
999 -- computation finishes, if @hdl@ is writable its buffer is flushed as
1001 -- Performing 'hClose' on a handle that has already been closed has no effect;
1002 -- doing so not an error. All other operations on a closed handle will fail.
1003 -- If 'hClose' fails for any reason, any further operations (apart from
1004 -- 'hClose') on the handle will still fail as if @hdl@ had been successfully
1007 hClose :: Handle -> IO ()
1008 hClose h@(FileHandle _ m) = hClose' h m
1009 hClose h@(DuplexHandle _ r w) = hClose' h w >> hClose' h r
1011 hClose' h m = withHandle__' "hClose" h m $ hClose_help
1013 -- hClose_help is also called by lazyRead (in PrelIO) when EOF is read
1014 -- or an IO error occurs on a lazy stream. The semi-closed Handle is
1015 -- then closed immediately. We have to be careful with DuplexHandles
1016 -- though: we have to leave the closing to the finalizer in that case,
1017 -- because the write side may still be in use.
1018 hClose_help :: Handle__ -> IO Handle__
1019 hClose_help handle_ =
1020 case haType handle_ of
1021 ClosedHandle -> return handle_
1022 _ -> do flushWriteBufferOnly handle_ -- interruptible
1023 hClose_handle_ handle_
1025 hClose_handle_ handle_ = do
1026 let fd = haFD handle_
1027 c_fd = fromIntegral fd
1029 -- close the file descriptor, but not when this is the read
1030 -- side of a duplex handle, and not when this is one of the
1031 -- std file handles.
1032 case haOtherSide handle_ of
1034 when (fd /= fd_stdin && fd /= fd_stdout && fd /= fd_stderr) $
1035 throwErrnoIfMinus1Retry_ "hClose"
1036 #ifdef mingw32_TARGET_OS
1037 (closeFd (haIsStream handle_) c_fd)
1043 -- free the spare buffers
1044 writeIORef (haBuffers handle_) BufferListNil
1046 #ifndef mingw32_TARGET_OS
1051 -- we must set the fd to -1, because the finalizer is going
1052 -- to run eventually and try to close/unlock it.
1053 return (handle_{ haFD = -1,
1054 haType = ClosedHandle
1057 -----------------------------------------------------------------------------
1058 -- Detecting and changing the size of a file
1060 -- | For a handle @hdl@ which attached to a physical file,
1061 -- 'hFileSize' @hdl@ returns the size of that file in 8-bit bytes.
1063 hFileSize :: Handle -> IO Integer
1065 withHandle_ "hFileSize" handle $ \ handle_ -> do
1066 case haType handle_ of
1067 ClosedHandle -> ioe_closedHandle
1068 SemiClosedHandle -> ioe_closedHandle
1069 _ -> do flushWriteBufferOnly handle_
1070 r <- fdFileSize (haFD handle_)
1073 else ioException (IOError Nothing InappropriateType "hFileSize"
1074 "not a regular file" Nothing)
1077 -- | 'hSetFileSize' @hdl@ @size@ truncates the physical file with handle @hdl@ to @size@ bytes.
1079 hSetFileSize :: Handle -> Integer -> IO ()
1080 hSetFileSize handle size =
1081 withHandle_ "hSetFileSize" handle $ \ handle_ -> do
1082 case haType handle_ of
1083 ClosedHandle -> ioe_closedHandle
1084 SemiClosedHandle -> ioe_closedHandle
1085 _ -> do flushWriteBufferOnly handle_
1086 throwErrnoIf (/=0) "hSetFileSize"
1087 (c_ftruncate (fromIntegral (haFD handle_)) (fromIntegral size))
1090 -- ---------------------------------------------------------------------------
1091 -- Detecting the End of Input
1093 -- | For a readable handle @hdl@, 'hIsEOF' @hdl@ returns
1094 -- 'True' if no further input can be taken from @hdl@ or for a
1095 -- physical file, if the current I\/O position is equal to the length of
1096 -- the file. Otherwise, it returns 'False'.
1098 hIsEOF :: Handle -> IO Bool
1101 (do hLookAhead handle; return False)
1102 (\e -> if isEOFError e then return True else ioError e)
1104 -- | The computation 'isEOF' is identical to 'hIsEOF',
1105 -- except that it works only on 'stdin'.
1108 isEOF = hIsEOF stdin
1110 -- ---------------------------------------------------------------------------
1113 -- | Computation 'hLookAhead' returns the next character from the handle
1114 -- without removing it from the input buffer, blocking until a character
1117 -- This operation may fail with:
1119 -- * 'isEOFError' if the end of file has been reached.
1121 hLookAhead :: Handle -> IO Char
1122 hLookAhead handle = do
1123 wantReadableHandle "hLookAhead" handle $ \handle_ -> do
1124 let ref = haBuffer handle_
1126 is_line = haBufferMode handle_ == LineBuffering
1127 buf <- readIORef ref
1129 -- fill up the read buffer if necessary
1130 new_buf <- if bufferEmpty buf
1131 then fillReadBuffer fd is_line (haIsStream handle_) buf
1134 writeIORef ref new_buf
1136 (c,_) <- readCharFromBuffer (bufBuf buf) (bufRPtr buf)
1139 -- ---------------------------------------------------------------------------
1140 -- Buffering Operations
1142 -- Three kinds of buffering are supported: line-buffering,
1143 -- block-buffering or no-buffering. See GHC.IOBase for definition and
1144 -- further explanation of what the type represent.
1146 -- | Computation 'hSetBuffering' @hdl mode@ sets the mode of buffering for
1147 -- handle @hdl@ on subsequent reads and writes.
1149 -- If the buffer mode is changed from 'BlockBuffering' or
1150 -- 'LineBuffering' to 'NoBuffering', then
1152 -- * if @hdl@ is writable, the buffer is flushed as for 'hFlush';
1154 -- * if @hdl@ is not writable, the contents of the buffer is discarded.
1156 -- This operation may fail with:
1158 -- * 'isPermissionError' if the handle has already been used for reading
1159 -- or writing and the implementation does not allow the buffering mode
1162 hSetBuffering :: Handle -> BufferMode -> IO ()
1163 hSetBuffering handle mode =
1164 withAllHandles__ "hSetBuffering" handle $ \ handle_ -> do
1165 case haType handle_ of
1166 ClosedHandle -> ioe_closedHandle
1169 - we flush the old buffer regardless of whether
1170 the new buffer could fit the contents of the old buffer
1172 - allow a handle's buffering to change even if IO has
1173 occurred (ANSI C spec. does not allow this, nor did
1174 the previous implementation of IO.hSetBuffering).
1175 - a non-standard extension is to allow the buffering
1176 of semi-closed handles to change [sof 6/98]
1180 let state = initBufferState (haType handle_)
1183 -- we always have a 1-character read buffer for
1184 -- unbuffered handles: it's needed to
1185 -- support hLookAhead.
1186 NoBuffering -> allocateBuffer 1 ReadBuffer
1187 LineBuffering -> allocateBuffer dEFAULT_BUFFER_SIZE state
1188 BlockBuffering Nothing -> allocateBuffer dEFAULT_BUFFER_SIZE state
1189 BlockBuffering (Just n) | n <= 0 -> ioe_bufsiz n
1190 | otherwise -> allocateBuffer n state
1191 writeIORef (haBuffer handle_) new_buf
1193 -- for input terminals we need to put the terminal into
1194 -- cooked or raw mode depending on the type of buffering.
1195 is_tty <- fdIsTTY (haFD handle_)
1196 when (is_tty && isReadableHandleType (haType handle_)) $
1198 #ifndef mingw32_TARGET_OS
1199 -- 'raw' mode under win32 is a bit too specialised (and troublesome
1200 -- for most common uses), so simply disable its use here.
1201 NoBuffering -> setCooked (haFD handle_) False
1203 _ -> setCooked (haFD handle_) True
1205 -- throw away spare buffers, they might be the wrong size
1206 writeIORef (haBuffers handle_) BufferListNil
1208 return (handle_{ haBufferMode = mode })
1210 -- -----------------------------------------------------------------------------
1213 -- | The action 'hFlush' @hdl@ causes any items buffered for output
1214 -- in handle @hdl@ to be sent immediately to the operating system.
1216 -- This operation may fail with:
1218 -- * 'isFullError' if the device is full;
1220 -- * 'isPermissionError' if a system resource limit would be exceeded.
1221 -- It is unspecified whether the characters in the buffer are discarded
1222 -- or retained under these circumstances.
1224 hFlush :: Handle -> IO ()
1226 wantWritableHandle "hFlush" handle $ \ handle_ -> do
1227 buf <- readIORef (haBuffer handle_)
1228 if bufferIsWritable buf && not (bufferEmpty buf)
1229 then do flushed_buf <- flushWriteBuffer (haFD handle_) (haIsStream handle_) buf
1230 writeIORef (haBuffer handle_) flushed_buf
1234 -- -----------------------------------------------------------------------------
1235 -- Repositioning Handles
1237 data HandlePosn = HandlePosn Handle HandlePosition
1239 instance Eq HandlePosn where
1240 (HandlePosn h1 p1) == (HandlePosn h2 p2) = p1==p2 && h1==h2
1242 instance Show HandlePosn where
1243 showsPrec p (HandlePosn h pos) =
1244 showsPrec p h . showString " at position " . shows pos
1246 -- HandlePosition is the Haskell equivalent of POSIX' off_t.
1247 -- We represent it as an Integer on the Haskell side, but
1248 -- cheat slightly in that hGetPosn calls upon a C helper
1249 -- that reports the position back via (merely) an Int.
1250 type HandlePosition = Integer
1252 -- | Computation 'hGetPosn' @hdl@ returns the current I\/O position of
1253 -- @hdl@ as a value of the abstract type 'HandlePosn'.
1255 hGetPosn :: Handle -> IO HandlePosn
1256 hGetPosn handle = do
1257 posn <- hTell handle
1258 return (HandlePosn handle posn)
1260 -- | If a call to 'hGetPosn' @hdl@ returns a position @p@,
1261 -- then computation 'hSetPosn' @p@ sets the position of @hdl@
1262 -- to the position it held at the time of the call to 'hGetPosn'.
1264 -- This operation may fail with:
1266 -- * 'isPermissionError' if a system resource limit would be exceeded.
1268 hSetPosn :: HandlePosn -> IO ()
1269 hSetPosn (HandlePosn h i) = hSeek h AbsoluteSeek i
1271 -- ---------------------------------------------------------------------------
1274 -- | A mode that determines the effect of 'hSeek' @hdl mode i@, as follows:
1276 = AbsoluteSeek -- ^ the position of @hdl@ is set to @i@.
1277 | RelativeSeek -- ^ the position of @hdl@ is set to offset @i@
1278 -- from the current position.
1279 | SeekFromEnd -- ^ the position of @hdl@ is set to offset @i@
1280 -- from the end of the file.
1281 deriving (Eq, Ord, Ix, Enum, Read, Show)
1284 - when seeking using `SeekFromEnd', positive offsets (>=0) means
1285 seeking at or past EOF.
1287 - we possibly deviate from the report on the issue of seeking within
1288 the buffer and whether to flush it or not. The report isn't exactly
1292 -- | Computation 'hSeek' @hdl mode i@ sets the position of handle
1293 -- @hdl@ depending on @mode@.
1294 -- The offset @i@ is given in terms of 8-bit bytes.
1296 -- If @hdl@ is block- or line-buffered, then seeking to a position which is not
1297 -- in the current buffer will first cause any items in the output buffer to be
1298 -- written to the device, and then cause the input buffer to be discarded.
1299 -- Some handles may not be seekable (see 'hIsSeekable'), or only support a
1300 -- subset of the possible positioning operations (for instance, it may only
1301 -- be possible to seek to the end of a tape, or to a positive offset from
1302 -- the beginning or current position).
1303 -- It is not possible to set a negative I\/O position, or for
1304 -- a physical file, an I\/O position beyond the current end-of-file.
1306 -- This operation may fail with:
1308 -- * 'isPermissionError' if a system resource limit would be exceeded.
1310 hSeek :: Handle -> SeekMode -> Integer -> IO ()
1311 hSeek handle mode offset =
1312 wantSeekableHandle "hSeek" handle $ \ handle_ -> do
1314 puts ("hSeek " ++ show (mode,offset) ++ "\n")
1316 let ref = haBuffer handle_
1317 buf <- readIORef ref
1323 throwErrnoIfMinus1Retry_ "hSeek"
1324 (c_lseek (fromIntegral (haFD handle_)) (fromIntegral offset) whence)
1327 whence = case mode of
1328 AbsoluteSeek -> sEEK_SET
1329 RelativeSeek -> sEEK_CUR
1330 SeekFromEnd -> sEEK_END
1332 if bufferIsWritable buf
1333 then do new_buf <- flushWriteBuffer fd (haIsStream handle_) buf
1334 writeIORef ref new_buf
1338 if mode == RelativeSeek && offset >= 0 && offset < fromIntegral (w - r)
1339 then writeIORef ref buf{ bufRPtr = r + fromIntegral offset }
1342 new_buf <- flushReadBuffer (haFD handle_) buf
1343 writeIORef ref new_buf
1347 hTell :: Handle -> IO Integer
1349 wantSeekableHandle "hGetPosn" handle $ \ handle_ -> do
1351 #if defined(mingw32_TARGET_OS)
1352 -- urgh, on Windows we have to worry about \n -> \r\n translation,
1353 -- so we can't easily calculate the file position using the
1354 -- current buffer size. Just flush instead.
1357 let fd = fromIntegral (haFD handle_)
1358 posn <- fromIntegral `liftM`
1359 throwErrnoIfMinus1Retry "hGetPosn"
1360 (c_lseek fd 0 sEEK_CUR)
1362 let ref = haBuffer handle_
1363 buf <- readIORef ref
1366 | bufferIsWritable buf = posn + fromIntegral (bufWPtr buf)
1367 | otherwise = posn - fromIntegral (bufWPtr buf - bufRPtr buf)
1369 puts ("\nhGetPosn: (fd, posn, real_posn) = " ++ show (fd, posn, real_posn) ++ "\n")
1370 puts (" (bufWPtr, bufRPtr) = " ++ show (bufWPtr buf, bufRPtr buf) ++ "\n")
1374 -- -----------------------------------------------------------------------------
1375 -- Handle Properties
1377 -- A number of operations return information about the properties of a
1378 -- handle. Each of these operations returns `True' if the handle has
1379 -- the specified property, and `False' otherwise.
1381 hIsOpen :: Handle -> IO Bool
1383 withHandle_ "hIsOpen" handle $ \ handle_ -> do
1384 case haType handle_ of
1385 ClosedHandle -> return False
1386 SemiClosedHandle -> return False
1389 hIsClosed :: Handle -> IO Bool
1391 withHandle_ "hIsClosed" handle $ \ handle_ -> do
1392 case haType handle_ of
1393 ClosedHandle -> return True
1396 {- not defined, nor exported, but mentioned
1397 here for documentation purposes:
1399 hSemiClosed :: Handle -> IO Bool
1403 return (not (ho || hc))
1406 hIsReadable :: Handle -> IO Bool
1407 hIsReadable (DuplexHandle _ _ _) = return True
1408 hIsReadable handle =
1409 withHandle_ "hIsReadable" handle $ \ handle_ -> do
1410 case haType handle_ of
1411 ClosedHandle -> ioe_closedHandle
1412 SemiClosedHandle -> ioe_closedHandle
1413 htype -> return (isReadableHandleType htype)
1415 hIsWritable :: Handle -> IO Bool
1416 hIsWritable (DuplexHandle _ _ _) = return True
1417 hIsWritable handle =
1418 withHandle_ "hIsWritable" handle $ \ handle_ -> do
1419 case haType handle_ of
1420 ClosedHandle -> ioe_closedHandle
1421 SemiClosedHandle -> ioe_closedHandle
1422 htype -> return (isWritableHandleType htype)
1424 -- | Computation 'hGetBuffering' @hdl@ returns the current buffering mode
1427 hGetBuffering :: Handle -> IO BufferMode
1428 hGetBuffering handle =
1429 withHandle_ "hGetBuffering" handle $ \ handle_ -> do
1430 case haType handle_ of
1431 ClosedHandle -> ioe_closedHandle
1433 -- We're being non-standard here, and allow the buffering
1434 -- of a semi-closed handle to be queried. -- sof 6/98
1435 return (haBufferMode handle_) -- could be stricter..
1437 hIsSeekable :: Handle -> IO Bool
1438 hIsSeekable handle =
1439 withHandle_ "hIsSeekable" handle $ \ handle_ -> do
1440 case haType handle_ of
1441 ClosedHandle -> ioe_closedHandle
1442 SemiClosedHandle -> ioe_closedHandle
1443 AppendHandle -> return False
1444 _ -> do t <- fdType (haFD handle_)
1445 return (t == RegularFile
1447 || tEXT_MODE_SEEK_ALLOWED))
1449 -- -----------------------------------------------------------------------------
1450 -- Changing echo status (Non-standard GHC extensions)
1452 -- | Set the echoing status of a handle connected to a terminal.
1454 hSetEcho :: Handle -> Bool -> IO ()
1455 hSetEcho handle on = do
1456 isT <- hIsTerminalDevice handle
1460 withHandle_ "hSetEcho" handle $ \ handle_ -> do
1461 case haType handle_ of
1462 ClosedHandle -> ioe_closedHandle
1463 _ -> setEcho (haFD handle_) on
1465 -- | Get the echoing status of a handle connected to a terminal.
1467 hGetEcho :: Handle -> IO Bool
1468 hGetEcho handle = do
1469 isT <- hIsTerminalDevice handle
1473 withHandle_ "hGetEcho" handle $ \ handle_ -> do
1474 case haType handle_ of
1475 ClosedHandle -> ioe_closedHandle
1476 _ -> getEcho (haFD handle_)
1478 -- | Is the handle connected to a terminal?
1480 hIsTerminalDevice :: Handle -> IO Bool
1481 hIsTerminalDevice handle = do
1482 withHandle_ "hIsTerminalDevice" handle $ \ handle_ -> do
1483 case haType handle_ of
1484 ClosedHandle -> ioe_closedHandle
1485 _ -> fdIsTTY (haFD handle_)
1487 -- -----------------------------------------------------------------------------
1490 -- | Select binary mode ('True') or text mode ('False') on a open handle.
1491 -- (See also 'openBinaryFile'.)
1493 hSetBinaryMode :: Handle -> Bool -> IO ()
1494 hSetBinaryMode handle bin =
1495 withAllHandles__ "hSetBinaryMode" handle $ \ handle_ ->
1496 do throwErrnoIfMinus1_ "hSetBinaryMode"
1497 (setmode (fromIntegral (haFD handle_)) bin)
1498 return handle_{haIsBin=bin}
1500 foreign import ccall unsafe "__hscore_setmode"
1501 setmode :: CInt -> Bool -> IO CInt
1503 -- -----------------------------------------------------------------------------
1504 -- Duplicating a Handle
1506 -- |Returns a duplicate of the original handle, with its own buffer
1507 -- and file pointer. The original handle's buffer is flushed, including
1508 -- discarding any input data, before the handle is duplicated.
1510 hDuplicate :: Handle -> IO Handle
1511 hDuplicate h@(FileHandle path m) = do
1512 new_h_ <- withHandle' "hDuplicate" h m (dupHandle_ Nothing)
1513 newFileHandle path (handleFinalizer path) new_h_
1514 hDuplicate h@(DuplexHandle path r w) = do
1515 new_w_ <- withHandle' "hDuplicate" h w (dupHandle_ Nothing)
1516 new_w <- newMVar new_w_
1517 new_r_ <- withHandle' "hDuplicate" h r (dupHandle_ (Just new_w))
1518 new_r <- newMVar new_r_
1519 addMVarFinalizer new_w (handleFinalizer path new_w)
1520 return (DuplexHandle path new_r new_w)
1522 dupHandle_ other_side h_ = do
1523 -- flush the buffer first, so we don't have to copy its contents
1525 new_fd <- c_dup (fromIntegral (haFD h_))
1526 buffer <- allocateBuffer dEFAULT_BUFFER_SIZE (initBufferState (haType h_))
1527 ioref <- newIORef buffer
1528 ioref_buffers <- newIORef BufferListNil
1530 let new_handle_ = h_{ haFD = fromIntegral new_fd,
1532 haBuffers = ioref_buffers,
1533 haOtherSide = other_side }
1534 return (h_, new_handle_)
1536 -- -----------------------------------------------------------------------------
1537 -- Replacing a Handle
1540 Makes the second handle a duplicate of the first handle. The second
1541 handle will be closed first, if it is not already.
1543 This can be used to retarget the standard Handles, for example:
1545 > do h <- openFile "mystdout" WriteMode
1546 > hDuplicateTo h stdout
1549 hDuplicateTo :: Handle -> Handle -> IO ()
1550 hDuplicateTo h1@(FileHandle _ m1) h2@(FileHandle _ m2) = do
1551 withHandle__' "hDuplicateTo" h2 m2 $ \h2_ -> do
1552 _ <- hClose_help h2_
1553 withHandle' "hDuplicateTo" h1 m1 (dupHandle_ Nothing)
1554 hDuplicateTo h1@(DuplexHandle _ r1 w1) h2@(DuplexHandle _ r2 w2) = do
1555 withHandle__' "hDuplicateTo" h2 w2 $ \w2_ -> do
1556 _ <- hClose_help w2_
1557 withHandle' "hDuplicateTo" h1 r1 (dupHandle_ Nothing)
1558 withHandle__' "hDuplicateTo" h2 r2 $ \r2_ -> do
1559 _ <- hClose_help r2_
1560 withHandle' "hDuplicateTo" h1 r1 (dupHandle_ (Just w1))
1562 ioException (IOError (Just h1) IllegalOperation "hDuplicateTo"
1563 "handles are incompatible" Nothing)
1565 -- ---------------------------------------------------------------------------
1568 -- | 'hShow' is in the 'IO' monad, and gives more comprehensive output
1569 -- than the (pure) instance of 'Show' for 'Handle'.
1571 hShow :: Handle -> IO String
1572 hShow h@(FileHandle path _) = showHandle' path False h
1573 hShow h@(DuplexHandle path _ _) = showHandle' path True h
1575 showHandle' filepath is_duplex h =
1576 withHandle_ "showHandle" h $ \hdl_ ->
1578 showType | is_duplex = showString "duplex (read-write)"
1579 | otherwise = shows (haType hdl_)
1583 showHdl (haType hdl_)
1584 (showString "loc=" . showString filepath . showChar ',' .
1585 showString "type=" . showType . showChar ',' .
1586 showString "binary=" . shows (haIsBin hdl_) . showChar ',' .
1587 showString "buffering=" . showBufMode (unsafePerformIO (readIORef (haBuffer hdl_))) (haBufferMode hdl_) . showString "}" )
1591 showHdl :: HandleType -> ShowS -> ShowS
1594 ClosedHandle -> shows ht . showString "}"
1597 showBufMode :: Buffer -> BufferMode -> ShowS
1598 showBufMode buf bmo =
1600 NoBuffering -> showString "none"
1601 LineBuffering -> showString "line"
1602 BlockBuffering (Just n) -> showString "block " . showParen True (shows n)
1603 BlockBuffering Nothing -> showString "block " . showParen True (shows def)
1608 -- ---------------------------------------------------------------------------
1612 puts :: String -> IO ()
1613 puts s = withCString s $ \cstr -> do write_rawBuffer 1 False cstr 0 (fromIntegral (length s))
1617 -- -----------------------------------------------------------------------------
1620 throwErrnoIfMinus1RetryOnBlock :: String -> IO CInt -> IO CInt -> IO CInt
1621 throwErrnoIfMinus1RetryOnBlock loc f on_block =
1624 if (res :: CInt) == -1
1628 then throwErrnoIfMinus1RetryOnBlock loc f on_block
1629 else if err == eWOULDBLOCK || err == eAGAIN
1634 -- -----------------------------------------------------------------------------
1635 -- wrappers to platform-specific constants:
1637 foreign import ccall unsafe "__hscore_supportsTextMode"
1638 tEXT_MODE_SEEK_ALLOWED :: Bool
1640 foreign import ccall unsafe "__hscore_bufsiz" dEFAULT_BUFFER_SIZE :: Int
1641 foreign import ccall unsafe "__hscore_seek_cur" sEEK_CUR :: CInt
1642 foreign import ccall unsafe "__hscore_seek_set" sEEK_SET :: CInt
1643 foreign import ccall unsafe "__hscore_seek_end" sEEK_END :: CInt