/
Handle.hs
1674 lines (1399 loc) · 57.1 KB
/
Handle.hs
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{-# OPTIONS_GHC -fno-implicit-prelude -#include "HsBase.h" #-}
#undef DEBUG_DUMP
#undef DEBUG
-----------------------------------------------------------------------------
-- |
-- Module : GHC.Handle
-- Copyright : (c) The University of Glasgow, 1994-2001
-- License : see libraries/base/LICENSE
--
-- Maintainer : libraries@haskell.org
-- Stability : internal
-- Portability : non-portable
--
-- This module defines the basic operations on I\/O \"handles\".
--
-----------------------------------------------------------------------------
-- #hide
module GHC.Handle (
withHandle, withHandle', withHandle_,
wantWritableHandle, wantReadableHandle, wantSeekableHandle,
newEmptyBuffer, allocateBuffer, readCharFromBuffer, writeCharIntoBuffer,
flushWriteBufferOnly, flushWriteBuffer, flushReadBuffer,
fillReadBuffer, fillReadBufferWithoutBlocking,
readRawBuffer, readRawBufferPtr,
writeRawBuffer, writeRawBufferPtr,
#ifndef mingw32_HOST_OS
unlockFile,
#endif
ioe_closedHandle, ioe_EOF, ioe_notReadable, ioe_notWritable,
stdin, stdout, stderr,
IOMode(..), openFile, openBinaryFile, openTempFile, openBinaryTempFile, openFd, fdToHandle,
hFileSize, hSetFileSize, hIsEOF, isEOF, hLookAhead, hSetBuffering, hSetBinaryMode,
hFlush, hDuplicate, hDuplicateTo,
hClose, hClose_help,
HandlePosition, HandlePosn(..), hGetPosn, hSetPosn,
SeekMode(..), hSeek, hTell,
hIsOpen, hIsClosed, hIsReadable, hIsWritable, hGetBuffering, hIsSeekable,
hSetEcho, hGetEcho, hIsTerminalDevice,
hShow,
#ifdef DEBUG_DUMP
puts,
#endif
) where
import System.Directory.Internals
import Control.Monad
import Data.Bits
import Data.Maybe
import Foreign
import Foreign.C
import System.IO.Error
import System.Posix.Internals
import GHC.Real
import GHC.Arr
import GHC.Base
import GHC.Read ( Read )
import GHC.List
import GHC.IOBase
import GHC.Exception
import GHC.Enum
import GHC.Num ( Integer(..), Num(..) )
import GHC.Show
import GHC.Real ( toInteger )
#if defined(DEBUG_DUMP)
import GHC.Pack
#endif
import GHC.Conc
-- -----------------------------------------------------------------------------
-- TODO:
-- hWaitForInput blocks (should use a timeout)
-- unbuffered hGetLine is a bit dodgy
-- hSetBuffering: can't change buffering on a stream,
-- when the read buffer is non-empty? (no way to flush the buffer)
-- ---------------------------------------------------------------------------
-- Are files opened by default in text or binary mode, if the user doesn't
-- specify?
dEFAULT_OPEN_IN_BINARY_MODE = False :: Bool
-- ---------------------------------------------------------------------------
-- Creating a new handle
newFileHandle :: FilePath -> (MVar Handle__ -> IO ()) -> Handle__ -> IO Handle
newFileHandle filepath finalizer hc = do
m <- newMVar hc
addMVarFinalizer m (finalizer m)
return (FileHandle filepath m)
-- ---------------------------------------------------------------------------
-- Working with Handles
{-
In the concurrent world, handles are locked during use. This is done
by wrapping an MVar around the handle which acts as a mutex over
operations on the handle.
To avoid races, we use the following bracketing operations. The idea
is to obtain the lock, do some operation and replace the lock again,
whether the operation succeeded or failed. We also want to handle the
case where the thread receives an exception while processing the IO
operation: in these cases we also want to relinquish the lock.
There are three versions of @withHandle@: corresponding to the three
possible combinations of:
- the operation may side-effect the handle
- the operation may return a result
If the operation generates an error or an exception is raised, the
original handle is always replaced [ this is the case at the moment,
but we might want to revisit this in the future --SDM ].
-}
{-# INLINE withHandle #-}
withHandle :: String -> Handle -> (Handle__ -> IO (Handle__,a)) -> IO a
withHandle fun h@(FileHandle _ m) act = withHandle' fun h m act
withHandle fun h@(DuplexHandle _ m _) act = withHandle' fun h m act
withHandle' :: String -> Handle -> MVar Handle__
-> (Handle__ -> IO (Handle__,a)) -> IO a
withHandle' fun h m act =
block $ do
h_ <- takeMVar m
checkBufferInvariants h_
(h',v) <- catchException (act h_)
(\ err -> putMVar m h_ >>
case err of
IOException ex -> ioError (augmentIOError ex fun h)
_ -> throw err)
checkBufferInvariants h'
putMVar m h'
return v
{-# INLINE withHandle_ #-}
withHandle_ :: String -> Handle -> (Handle__ -> IO a) -> IO a
withHandle_ fun h@(FileHandle _ m) act = withHandle_' fun h m act
withHandle_ fun h@(DuplexHandle _ m _) act = withHandle_' fun h m act
withHandle_' fun h m act =
block $ do
h_ <- takeMVar m
checkBufferInvariants h_
v <- catchException (act h_)
(\ err -> putMVar m h_ >>
case err of
IOException ex -> ioError (augmentIOError ex fun h)
_ -> throw err)
checkBufferInvariants h_
putMVar m h_
return v
withAllHandles__ :: String -> Handle -> (Handle__ -> IO Handle__) -> IO ()
withAllHandles__ fun h@(FileHandle _ m) act = withHandle__' fun h m act
withAllHandles__ fun h@(DuplexHandle _ r w) act = do
withHandle__' fun h r act
withHandle__' fun h w act
withHandle__' fun h m act =
block $ do
h_ <- takeMVar m
checkBufferInvariants h_
h' <- catchException (act h_)
(\ err -> putMVar m h_ >>
case err of
IOException ex -> ioError (augmentIOError ex fun h)
_ -> throw err)
checkBufferInvariants h'
putMVar m h'
return ()
augmentIOError (IOError _ iot _ str fp) fun h
= IOError (Just h) iot fun str filepath
where filepath
| Just _ <- fp = fp
| otherwise = case h of
FileHandle fp _ -> Just fp
DuplexHandle fp _ _ -> Just fp
-- ---------------------------------------------------------------------------
-- Wrapper for write operations.
wantWritableHandle :: String -> Handle -> (Handle__ -> IO a) -> IO a
wantWritableHandle fun h@(FileHandle _ m) act
= wantWritableHandle' fun h m act
wantWritableHandle fun h@(DuplexHandle _ _ m) act
= wantWritableHandle' fun h m act
-- ToDo: in the Duplex case, we don't need to checkWritableHandle
wantWritableHandle'
:: String -> Handle -> MVar Handle__
-> (Handle__ -> IO a) -> IO a
wantWritableHandle' fun h m act
= withHandle_' fun h m (checkWritableHandle act)
checkWritableHandle act handle_
= case haType handle_ of
ClosedHandle -> ioe_closedHandle
SemiClosedHandle -> ioe_closedHandle
ReadHandle -> ioe_notWritable
ReadWriteHandle -> do
let ref = haBuffer handle_
buf <- readIORef ref
new_buf <-
if not (bufferIsWritable buf)
then do b <- flushReadBuffer (haFD handle_) buf
return b{ bufState=WriteBuffer }
else return buf
writeIORef ref new_buf
act handle_
_other -> act handle_
-- ---------------------------------------------------------------------------
-- Wrapper for read operations.
wantReadableHandle :: String -> Handle -> (Handle__ -> IO a) -> IO a
wantReadableHandle fun h@(FileHandle _ m) act
= wantReadableHandle' fun h m act
wantReadableHandle fun h@(DuplexHandle _ m _) act
= wantReadableHandle' fun h m act
-- ToDo: in the Duplex case, we don't need to checkReadableHandle
wantReadableHandle'
:: String -> Handle -> MVar Handle__
-> (Handle__ -> IO a) -> IO a
wantReadableHandle' fun h m act
= withHandle_' fun h m (checkReadableHandle act)
checkReadableHandle act handle_ =
case haType handle_ of
ClosedHandle -> ioe_closedHandle
SemiClosedHandle -> ioe_closedHandle
AppendHandle -> ioe_notReadable
WriteHandle -> ioe_notReadable
ReadWriteHandle -> do
let ref = haBuffer handle_
buf <- readIORef ref
when (bufferIsWritable buf) $ do
new_buf <- flushWriteBuffer (haFD handle_) (haIsStream handle_) buf
writeIORef ref new_buf{ bufState=ReadBuffer }
act handle_
_other -> act handle_
-- ---------------------------------------------------------------------------
-- Wrapper for seek operations.
wantSeekableHandle :: String -> Handle -> (Handle__ -> IO a) -> IO a
wantSeekableHandle fun h@(DuplexHandle _ _ _) _act =
ioException (IOError (Just h) IllegalOperation fun
"handle is not seekable" Nothing)
wantSeekableHandle fun h@(FileHandle _ m) act =
withHandle_' fun h m (checkSeekableHandle act)
checkSeekableHandle act handle_ =
case haType handle_ of
ClosedHandle -> ioe_closedHandle
SemiClosedHandle -> ioe_closedHandle
AppendHandle -> ioe_notSeekable
_ | haIsBin handle_ || tEXT_MODE_SEEK_ALLOWED -> act handle_
| otherwise -> ioe_notSeekable_notBin
-- -----------------------------------------------------------------------------
-- Handy IOErrors
ioe_closedHandle, ioe_EOF,
ioe_notReadable, ioe_notWritable,
ioe_notSeekable, ioe_notSeekable_notBin :: IO a
ioe_closedHandle = ioException
(IOError Nothing IllegalOperation ""
"handle is closed" Nothing)
ioe_EOF = ioException
(IOError Nothing EOF "" "" Nothing)
ioe_notReadable = ioException
(IOError Nothing IllegalOperation ""
"handle is not open for reading" Nothing)
ioe_notWritable = ioException
(IOError Nothing IllegalOperation ""
"handle is not open for writing" Nothing)
ioe_notSeekable = ioException
(IOError Nothing IllegalOperation ""
"handle is not seekable" Nothing)
ioe_notSeekable_notBin = ioException
(IOError Nothing IllegalOperation ""
"seek operations on text-mode handles are not allowed on this platform"
Nothing)
ioe_finalizedHandle fp = throw (IOException
(IOError Nothing IllegalOperation ""
"handle is finalized" (Just fp)))
ioe_bufsiz :: Int -> IO a
ioe_bufsiz n = ioException
(IOError Nothing InvalidArgument "hSetBuffering"
("illegal buffer size " ++ showsPrec 9 n []) Nothing)
-- 9 => should be parens'ified.
-- -----------------------------------------------------------------------------
-- Handle Finalizers
-- For a duplex handle, we arrange that the read side points to the write side
-- (and hence keeps it alive if the read side is alive). This is done by
-- having the haOtherSide field of the read side point to the read side.
-- The finalizer is then placed on the write side, and the handle only gets
-- finalized once, when both sides are no longer required.
-- NOTE about finalized handles: It's possible that a handle can be
-- finalized and then we try to use it later, for example if the
-- handle is referenced from another finalizer, or from a thread that
-- has become unreferenced and then resurrected (arguably in the
-- latter case we shouldn't finalize the Handle...). Anyway,
-- we try to emit a helpful message which is better than nothing.
stdHandleFinalizer :: FilePath -> MVar Handle__ -> IO ()
stdHandleFinalizer fp m = do
h_ <- takeMVar m
flushWriteBufferOnly h_
putMVar m (ioe_finalizedHandle fp)
handleFinalizer :: FilePath -> MVar Handle__ -> IO ()
handleFinalizer fp m = do
handle_ <- takeMVar m
case haType handle_ of
ClosedHandle -> return ()
_ -> do flushWriteBufferOnly handle_ `catchException` \_ -> return ()
-- ignore errors and async exceptions, and close the
-- descriptor anyway...
hClose_handle_ handle_
return ()
putMVar m (ioe_finalizedHandle fp)
-- ---------------------------------------------------------------------------
-- Grimy buffer operations
#ifdef DEBUG
checkBufferInvariants h_ = do
let ref = haBuffer h_
Buffer{ bufWPtr=w, bufRPtr=r, bufSize=size, bufState=state } <- readIORef ref
if not (
size > 0
&& r <= w
&& w <= size
&& ( r /= w || (r == 0 && w == 0) )
&& ( state /= WriteBuffer || r == 0 )
&& ( state /= WriteBuffer || w < size ) -- write buffer is never full
)
then error "buffer invariant violation"
else return ()
#else
checkBufferInvariants h_ = return ()
#endif
newEmptyBuffer :: RawBuffer -> BufferState -> Int -> Buffer
newEmptyBuffer b state size
= Buffer{ bufBuf=b, bufRPtr=0, bufWPtr=0, bufSize=size, bufState=state }
allocateBuffer :: Int -> BufferState -> IO Buffer
allocateBuffer sz@(I# size) state = IO $ \s ->
#ifdef mingw32_HOST_OS
-- To implement asynchronous I/O under Win32, we have to pass
-- buffer references to external threads that handles the
-- filling/emptying of their contents. Hence, the buffer cannot
-- be moved around by the GC.
case newPinnedByteArray# size s of { (# s, b #) ->
#else
case newByteArray# size s of { (# s, b #) ->
#endif
(# s, newEmptyBuffer b state sz #) }
writeCharIntoBuffer :: RawBuffer -> Int -> Char -> IO Int
writeCharIntoBuffer slab (I# off) (C# c)
= IO $ \s -> case writeCharArray# slab off c s of
s -> (# s, I# (off +# 1#) #)
readCharFromBuffer :: RawBuffer -> Int -> IO (Char, Int)
readCharFromBuffer slab (I# off)
= IO $ \s -> case readCharArray# slab off s of
(# s, c #) -> (# s, (C# c, I# (off +# 1#)) #)
getBuffer :: FD -> BufferState -> IO (IORef Buffer, BufferMode)
getBuffer fd state = do
buffer <- allocateBuffer dEFAULT_BUFFER_SIZE state
ioref <- newIORef buffer
is_tty <- fdIsTTY fd
let buffer_mode
| is_tty = LineBuffering
| otherwise = BlockBuffering Nothing
return (ioref, buffer_mode)
mkUnBuffer :: IO (IORef Buffer)
mkUnBuffer = do
buffer <- allocateBuffer 1 ReadBuffer
newIORef buffer
-- flushWriteBufferOnly flushes the buffer iff it contains pending write data.
flushWriteBufferOnly :: Handle__ -> IO ()
flushWriteBufferOnly h_ = do
let fd = haFD h_
ref = haBuffer h_
buf <- readIORef ref
new_buf <- if bufferIsWritable buf
then flushWriteBuffer fd (haIsStream h_) buf
else return buf
writeIORef ref new_buf
-- flushBuffer syncs the file with the buffer, including moving the
-- file pointer backwards in the case of a read buffer.
flushBuffer :: Handle__ -> IO ()
flushBuffer h_ = do
let ref = haBuffer h_
buf <- readIORef ref
flushed_buf <-
case bufState buf of
ReadBuffer -> flushReadBuffer (haFD h_) buf
WriteBuffer -> flushWriteBuffer (haFD h_) (haIsStream h_) buf
writeIORef ref flushed_buf
-- When flushing a read buffer, we seek backwards by the number of
-- characters in the buffer. The file descriptor must therefore be
-- seekable: attempting to flush the read buffer on an unseekable
-- handle is not allowed.
flushReadBuffer :: FD -> Buffer -> IO Buffer
flushReadBuffer fd buf
| bufferEmpty buf = return buf
| otherwise = do
let off = negate (bufWPtr buf - bufRPtr buf)
# ifdef DEBUG_DUMP
puts ("flushReadBuffer: new file offset = " ++ show off ++ "\n")
# endif
throwErrnoIfMinus1Retry "flushReadBuffer"
(c_lseek (fromIntegral fd) (fromIntegral off) sEEK_CUR)
return buf{ bufWPtr=0, bufRPtr=0 }
flushWriteBuffer :: FD -> Bool -> Buffer -> IO Buffer
flushWriteBuffer fd is_stream buf@Buffer{ bufBuf=b, bufRPtr=r, bufWPtr=w } =
seq fd $ do -- strictness hack
let bytes = w - r
#ifdef DEBUG_DUMP
puts ("flushWriteBuffer, fd=" ++ show fd ++ ", bytes=" ++ show bytes ++ "\n")
#endif
if bytes == 0
then return (buf{ bufRPtr=0, bufWPtr=0 })
else do
res <- writeRawBuffer "flushWriteBuffer" (fromIntegral fd) is_stream b
(fromIntegral r) (fromIntegral bytes)
let res' = fromIntegral res
if res' < bytes
then flushWriteBuffer fd is_stream (buf{ bufRPtr = r + res' })
else return buf{ bufRPtr=0, bufWPtr=0 }
fillReadBuffer :: FD -> Bool -> Bool -> Buffer -> IO Buffer
fillReadBuffer fd is_line is_stream
buf@Buffer{ bufBuf=b, bufRPtr=r, bufWPtr=w, bufSize=size } =
-- buffer better be empty:
assert (r == 0 && w == 0) $ do
fillReadBufferLoop fd is_line is_stream buf b w size
-- For a line buffer, we just get the first chunk of data to arrive,
-- and don't wait for the whole buffer to be full (but we *do* wait
-- until some data arrives). This isn't really line buffering, but it
-- appears to be what GHC has done for a long time, and I suspect it
-- is more useful than line buffering in most cases.
fillReadBufferLoop fd is_line is_stream buf b w size = do
let bytes = size - w
if bytes == 0 -- buffer full?
then return buf{ bufRPtr=0, bufWPtr=w }
else do
#ifdef DEBUG_DUMP
puts ("fillReadBufferLoop: bytes = " ++ show bytes ++ "\n")
#endif
res <- readRawBuffer "fillReadBuffer" fd is_stream b
(fromIntegral w) (fromIntegral bytes)
let res' = fromIntegral res
#ifdef DEBUG_DUMP
puts ("fillReadBufferLoop: res' = " ++ show res' ++ "\n")
#endif
if res' == 0
then if w == 0
then ioe_EOF
else return buf{ bufRPtr=0, bufWPtr=w }
else if res' < bytes && not is_line
then fillReadBufferLoop fd is_line is_stream buf b (w+res') size
else return buf{ bufRPtr=0, bufWPtr=w+res' }
fillReadBufferWithoutBlocking :: FD -> Bool -> Buffer -> IO Buffer
fillReadBufferWithoutBlocking fd is_stream
buf@Buffer{ bufBuf=b, bufRPtr=r, bufWPtr=w, bufSize=size } =
-- buffer better be empty:
assert (r == 0 && w == 0) $ do
#ifdef DEBUG_DUMP
puts ("fillReadBufferLoopNoBlock: bytes = " ++ show size ++ "\n")
#endif
res <- readRawBufferNoBlock "fillReadBuffer" fd is_stream b
0 (fromIntegral size)
let res' = fromIntegral res
#ifdef DEBUG_DUMP
puts ("fillReadBufferLoopNoBlock: res' = " ++ show res' ++ "\n")
#endif
return buf{ bufRPtr=0, bufWPtr=res' }
-- Low level routines for reading/writing to (raw)buffers:
#ifndef mingw32_HOST_OS
readRawBuffer :: String -> FD -> Bool -> RawBuffer -> Int -> CInt -> IO CInt
readRawBuffer loc fd is_stream buf off len =
throwErrnoIfMinus1RetryMayBlock loc
(read_rawBuffer fd buf off len)
(threadWaitRead (fromIntegral fd))
readRawBufferNoBlock :: String -> FD -> Bool -> RawBuffer -> Int -> CInt -> IO CInt
readRawBufferNoBlock loc fd is_stream buf off len =
throwErrnoIfMinus1RetryOnBlock loc
(read_rawBuffer fd buf off len)
(return 0)
readRawBufferPtr :: String -> FD -> Bool -> Ptr CChar -> Int -> CInt -> IO CInt
readRawBufferPtr loc fd is_stream buf off len =
throwErrnoIfMinus1RetryMayBlock loc
(read_off fd buf off len)
(threadWaitRead (fromIntegral fd))
writeRawBuffer :: String -> FD -> Bool -> RawBuffer -> Int -> CInt -> IO CInt
writeRawBuffer loc fd is_stream buf off len =
throwErrnoIfMinus1RetryMayBlock loc
(write_rawBuffer (fromIntegral fd) buf off len)
(threadWaitWrite (fromIntegral fd))
writeRawBufferPtr :: String -> FD -> Bool -> Ptr CChar -> Int -> CInt -> IO CInt
writeRawBufferPtr loc fd is_stream buf off len =
throwErrnoIfMinus1RetryMayBlock loc
(write_off (fromIntegral fd) buf off len)
(threadWaitWrite (fromIntegral fd))
foreign import ccall unsafe "__hscore_PrelHandle_read"
read_rawBuffer :: FD -> RawBuffer -> Int -> CInt -> IO CInt
foreign import ccall unsafe "__hscore_PrelHandle_read"
read_off :: FD -> Ptr CChar -> Int -> CInt -> IO CInt
foreign import ccall unsafe "__hscore_PrelHandle_write"
write_rawBuffer :: CInt -> RawBuffer -> Int -> CInt -> IO CInt
foreign import ccall unsafe "__hscore_PrelHandle_write"
write_off :: CInt -> Ptr CChar -> Int -> CInt -> IO CInt
#else /* mingw32_HOST_OS.... */
readRawBuffer :: String -> FD -> Bool -> RawBuffer -> Int -> CInt -> IO CInt
readRawBuffer loc fd is_stream buf off len
| threaded = blockingReadRawBuffer loc fd is_stream buf off len
| otherwise = asyncReadRawBuffer loc fd is_stream buf off len
readRawBufferPtr :: String -> FD -> Bool -> Ptr CChar -> Int -> CInt -> IO CInt
readRawBufferPtr loc fd is_stream buf off len
| threaded = blockingReadRawBufferPtr loc fd is_stream buf off len
| otherwise = asyncReadRawBufferPtr loc fd is_stream buf off len
writeRawBuffer :: String -> FD -> Bool -> RawBuffer -> Int -> CInt -> IO CInt
writeRawBuffer loc fd is_stream buf off len
| threaded = blockingWriteRawBuffer loc fd is_stream buf off len
| otherwise = asyncWriteRawBuffer loc fd is_stream buf off len
writeRawBufferPtr :: String -> FD -> Bool -> Ptr CChar -> Int -> CInt -> IO CInt
writeRawBufferPtr loc fd is_stream buf off len
| threaded = blockingWriteRawBufferPtr loc fd is_stream buf off len
| otherwise = asyncWriteRawBufferPtr loc fd is_stream buf off len
-- ToDo: we don't have a non-blocking primitve read on Win32
readRawBufferNoBlock :: String -> FD -> Bool -> RawBuffer -> Int -> CInt -> IO CInt
readRawBufferNoBlock = readRawBufferNoBlock
-- Async versions of the read/write primitives, for the non-threaded RTS
asyncReadRawBuffer loc fd is_stream buf off len = do
(l, rc) <- asyncReadBA fd (if is_stream then 1 else 0)
(fromIntegral len) off buf
if l == (-1)
then
ioError (errnoToIOError loc (Errno (fromIntegral rc)) Nothing Nothing)
else return (fromIntegral l)
asyncReadRawBufferPtr loc fd is_stream buf off len = do
(l, rc) <- asyncRead fd (if is_stream then 1 else 0)
(fromIntegral len) (buf `plusPtr` off)
if l == (-1)
then
ioError (errnoToIOError loc (Errno (fromIntegral rc)) Nothing Nothing)
else return (fromIntegral l)
asyncWriteRawBuffer loc fd is_stream buf off len = do
(l, rc) <- asyncWriteBA fd (if is_stream then 1 else 0)
(fromIntegral len) off buf
if l == (-1)
then
ioError (errnoToIOError loc (Errno (fromIntegral rc)) Nothing Nothing)
else return (fromIntegral l)
asyncWriteRawBufferPtr loc fd is_stream buf off len = do
(l, rc) <- asyncWrite fd (if is_stream then 1 else 0)
(fromIntegral len) (buf `plusPtr` off)
if l == (-1)
then
ioError (errnoToIOError loc (Errno (fromIntegral rc)) Nothing Nothing)
else return (fromIntegral l)
-- Blocking versions of the read/write primitives, for the threaded RTS
blockingReadRawBuffer loc fd True buf off len =
throwErrnoIfMinus1Retry loc $
recv_rawBuffer fd buf off len
blockingReadRawBuffer loc fd False buf off len =
throwErrnoIfMinus1Retry loc $
read_rawBuffer fd buf off len
blockingReadRawBufferPtr loc fd True buf off len =
throwErrnoIfMinus1Retry loc $
recv_off fd buf off len
blockingReadRawBufferPtr loc fd False buf off len =
throwErrnoIfMinus1Retry loc $
read_off fd buf off len
blockingWriteRawBuffer loc fd True buf off len =
throwErrnoIfMinus1Retry loc $
send_rawBuffer (fromIntegral fd) buf off len
blockingWriteRawBuffer loc fd False buf off len =
throwErrnoIfMinus1Retry loc $
write_rawBuffer (fromIntegral fd) buf off len
blockingWriteRawBufferPtr loc fd True buf off len =
throwErrnoIfMinus1Retry loc $
send_off (fromIntegral fd) buf off len
blockingWriteRawBufferPtr loc fd False buf off len =
throwErrnoIfMinus1Retry loc $
write_off (fromIntegral fd) buf off len
-- NOTE: "safe" versions of the read/write calls for use by the threaded RTS.
-- These calls may block, but that's ok.
foreign import ccall safe "__hscore_PrelHandle_read"
read_rawBuffer :: FD -> RawBuffer -> Int -> CInt -> IO CInt
foreign import ccall safe "__hscore_PrelHandle_read"
read_off :: FD -> Ptr CChar -> Int -> CInt -> IO CInt
foreign import ccall safe "__hscore_PrelHandle_write"
write_rawBuffer :: CInt -> RawBuffer -> Int -> CInt -> IO CInt
foreign import ccall safe "__hscore_PrelHandle_write"
write_off :: CInt -> Ptr CChar -> Int -> CInt -> IO CInt
foreign import ccall safe "__hscore_PrelHandle_recv"
recv_rawBuffer :: FD -> RawBuffer -> Int -> CInt -> IO CInt
foreign import ccall safe "__hscore_PrelHandle_recv"
recv_off :: FD -> Ptr CChar -> Int -> CInt -> IO CInt
foreign import ccall safe "__hscore_PrelHandle_send"
send_rawBuffer :: CInt -> RawBuffer -> Int -> CInt -> IO CInt
foreign import ccall safe "__hscore_PrelHandle_send"
send_off :: CInt -> Ptr CChar -> Int -> CInt -> IO CInt
foreign import ccall "rtsSupportsBoundThreads" threaded :: Bool
#endif
-- ---------------------------------------------------------------------------
-- Standard Handles
-- Three handles are allocated during program initialisation. The first
-- two manage input or output from the Haskell program's standard input
-- or output channel respectively. The third manages output to the
-- standard error channel. These handles are initially open.
fd_stdin = 0 :: FD
fd_stdout = 1 :: FD
fd_stderr = 2 :: FD
-- | A handle managing input from the Haskell program's standard input channel.
stdin :: Handle
stdin = unsafePerformIO $ do
-- ToDo: acquire lock
setNonBlockingFD fd_stdin
(buf, bmode) <- getBuffer fd_stdin ReadBuffer
mkStdHandle fd_stdin "<stdin>" ReadHandle buf bmode
-- | A handle managing output to the Haskell program's standard output channel.
stdout :: Handle
stdout = unsafePerformIO $ do
-- ToDo: acquire lock
-- We don't set non-blocking mode on stdout or sterr, because
-- some shells don't recover properly.
-- setNonBlockingFD fd_stdout
(buf, bmode) <- getBuffer fd_stdout WriteBuffer
mkStdHandle fd_stdout "<stdout>" WriteHandle buf bmode
-- | A handle managing output to the Haskell program's standard error channel.
stderr :: Handle
stderr = unsafePerformIO $ do
-- ToDo: acquire lock
-- We don't set non-blocking mode on stdout or sterr, because
-- some shells don't recover properly.
-- setNonBlockingFD fd_stderr
buf <- mkUnBuffer
mkStdHandle fd_stderr "<stderr>" WriteHandle buf NoBuffering
-- ---------------------------------------------------------------------------
-- Opening and Closing Files
addFilePathToIOError fun fp (IOError h iot _ str _)
= IOError h iot fun str (Just fp)
-- | Computation 'openFile' @file mode@ allocates and returns a new, open
-- handle to manage the file @file@. It manages input if @mode@
-- is 'ReadMode', output if @mode@ is 'WriteMode' or 'AppendMode',
-- and both input and output if mode is 'ReadWriteMode'.
--
-- If the file does not exist and it is opened for output, it should be
-- created as a new file. If @mode@ is 'WriteMode' and the file
-- already exists, then it should be truncated to zero length.
-- Some operating systems delete empty files, so there is no guarantee
-- that the file will exist following an 'openFile' with @mode@
-- 'WriteMode' unless it is subsequently written to successfully.
-- The handle is positioned at the end of the file if @mode@ is
-- 'AppendMode', and otherwise at the beginning (in which case its
-- internal position is 0).
-- The initial buffer mode is implementation-dependent.
--
-- This operation may fail with:
--
-- * 'isAlreadyInUseError' if the file is already open and cannot be reopened;
--
-- * 'isDoesNotExistError' if the file does not exist; or
--
-- * 'isPermissionError' if the user does not have permission to open the file.
--
-- Note: if you will be working with files containing binary data, you'll want to
-- be using 'openBinaryFile'.
openFile :: FilePath -> IOMode -> IO Handle
openFile fp im =
catch
(openFile' fp im dEFAULT_OPEN_IN_BINARY_MODE)
(\e -> ioError (addFilePathToIOError "openFile" fp e))
-- | Like 'openFile', but open the file in binary mode.
-- On Windows, reading a file in text mode (which is the default)
-- will translate CRLF to LF, and writing will translate LF to CRLF.
-- This is usually what you want with text files. With binary files
-- this is undesirable; also, as usual under Microsoft operating systems,
-- text mode treats control-Z as EOF. Binary mode turns off all special
-- treatment of end-of-line and end-of-file characters.
-- (See also 'hSetBinaryMode'.)
openBinaryFile :: FilePath -> IOMode -> IO Handle
openBinaryFile fp m =
catch
(openFile' fp m True)
(\e -> ioError (addFilePathToIOError "openBinaryFile" fp e))
openFile' filepath mode binary =
withCString filepath $ \ f ->
let
oflags1 = case mode of
ReadMode -> read_flags
#ifdef mingw32_HOST_OS
WriteMode -> write_flags .|. o_TRUNC
#else
WriteMode -> write_flags
#endif
ReadWriteMode -> rw_flags
AppendMode -> append_flags
binary_flags
| binary = o_BINARY
| otherwise = 0
oflags = oflags1 .|. binary_flags
in do
-- the old implementation had a complicated series of three opens,
-- which is perhaps because we have to be careful not to open
-- directories. However, the man pages I've read say that open()
-- always returns EISDIR if the file is a directory and was opened
-- for writing, so I think we're ok with a single open() here...
fd <- fromIntegral `liftM`
throwErrnoIfMinus1Retry "openFile"
(c_open f (fromIntegral oflags) 0o666)
fd_type <- fdType fd
h <- openFd fd (Just fd_type) False filepath mode binary
`catchException` \e -> do c_close (fromIntegral fd); throw e
-- NB. don't forget to close the FD if openFd fails, otherwise
-- this FD leaks.
-- ASSERT: if we just created the file, then openFd won't fail
-- (so we don't need to worry about removing the newly created file
-- in the event of an error).
#ifndef mingw32_HOST_OS
-- we want to truncate() if this is an open in WriteMode, but only
-- if the target is a RegularFile. ftruncate() fails on special files
-- like /dev/null.
if mode == WriteMode && fd_type == RegularFile
then throwErrnoIf (/=0) "openFile"
(c_ftruncate (fromIntegral fd) 0)
else return 0
#endif
return h
-- | The function creates a temporary file in ReadWrite mode.
-- The created file isn\'t deleted automatically, so you need to delete it manually.
openTempFile :: FilePath -- ^ Directory in which to create the file
-> String -- ^ File name template. If the template is \"foo.ext\" then
-- the create file will be \"fooXXX.ext\" where XXX is some
-- random number.
-> IO (FilePath, Handle)
openTempFile tmp_dir template = openTempFile' "openTempFile" tmp_dir template dEFAULT_OPEN_IN_BINARY_MODE
-- | Like 'openTempFile', but opens the file in binary mode. See 'openBinaryFile' for more comments.
openBinaryTempFile :: FilePath -> String -> IO (FilePath, Handle)
openBinaryTempFile tmp_dir template = openTempFile' "openBinaryTempFile" tmp_dir template True
openTempFile' :: String -> FilePath -> String -> Bool -> IO (FilePath, Handle)
openTempFile' loc tmp_dir template binary = do
pid <- c_getpid
findTempName pid
where
(prefix,suffix) = break (=='.') template
oflags1 = rw_flags .|. o_EXCL
binary_flags
| binary = o_BINARY
| otherwise = 0
oflags = oflags1 .|. binary_flags
findTempName x = do
fd <- withCString filepath $ \ f ->
c_open f oflags 0o666
if fd < 0
then do
errno <- getErrno
if errno == eEXIST
then findTempName (x+1)
else ioError (errnoToIOError loc errno Nothing (Just tmp_dir))
else do
h <- openFd (fromIntegral fd) Nothing False filepath ReadWriteMode True
`catchException` \e -> do c_close (fromIntegral fd); throw e
return (filepath, h)
where
filename = prefix ++ show x ++ suffix
filepath = tmp_dir `joinFileName` filename
std_flags = o_NONBLOCK .|. o_NOCTTY
output_flags = std_flags .|. o_CREAT
read_flags = std_flags .|. o_RDONLY
write_flags = output_flags .|. o_WRONLY
rw_flags = output_flags .|. o_RDWR
append_flags = write_flags .|. o_APPEND
-- ---------------------------------------------------------------------------
-- openFd
openFd :: FD -> Maybe FDType -> Bool -> FilePath -> IOMode -> Bool -> IO Handle
openFd fd mb_fd_type is_socket filepath mode binary = do
-- turn on non-blocking mode
setNonBlockingFD fd
let (ha_type, write) =
case mode of
ReadMode -> ( ReadHandle, False )
WriteMode -> ( WriteHandle, True )
ReadWriteMode -> ( ReadWriteHandle, True )
AppendMode -> ( AppendHandle, True )
-- open() won't tell us if it was a directory if we only opened for
-- reading, so check again.
fd_type <-
case mb_fd_type of
Just x -> return x
Nothing -> fdType fd
case fd_type of
Directory ->
ioException (IOError Nothing InappropriateType "openFile"
"is a directory" Nothing)
Stream
| ReadWriteHandle <- ha_type -> mkDuplexHandle fd is_socket filepath binary
| otherwise -> mkFileHandle fd is_socket filepath ha_type binary
-- regular files need to be locked
RegularFile -> do
#ifndef mingw32_HOST_OS
r <- lockFile (fromIntegral fd) (fromBool write) 1{-exclusive-}
when (r == -1) $
ioException (IOError Nothing ResourceBusy "openFile"
"file is locked" Nothing)
#endif
mkFileHandle fd is_socket filepath ha_type binary
fdToHandle :: FD -> IO Handle
fdToHandle fd = do
mode <- fdGetMode fd
let fd_str = "<file descriptor: " ++ show fd ++ ">"
openFd fd Nothing False{-XXX!-} fd_str mode True{-bin mode-}
#ifndef mingw32_HOST_OS
foreign import ccall unsafe "lockFile"
lockFile :: CInt -> CInt -> CInt -> IO CInt
foreign import ccall unsafe "unlockFile"
unlockFile :: CInt -> IO CInt
#endif
mkStdHandle :: FD -> FilePath -> HandleType -> IORef Buffer -> BufferMode
-> IO Handle
mkStdHandle fd filepath ha_type buf bmode = do
spares <- newIORef BufferListNil
newFileHandle filepath (stdHandleFinalizer filepath)
(Handle__ { haFD = fd,
haType = ha_type,
haIsBin = dEFAULT_OPEN_IN_BINARY_MODE,
haIsStream = False,
haBufferMode = bmode,
haBuffer = buf,
haBuffers = spares,
haOtherSide = Nothing
})
mkFileHandle :: FD -> Bool -> FilePath -> HandleType -> Bool -> IO Handle
mkFileHandle fd is_stream filepath ha_type binary = do
(buf, bmode) <- getBuffer fd (initBufferState ha_type)
spares <- newIORef BufferListNil
newFileHandle filepath (handleFinalizer filepath)
(Handle__ { haFD = fd,
haType = ha_type,
haIsBin = binary,
haIsStream = is_stream,
haBufferMode = bmode,
haBuffer = buf,
haBuffers = spares,
haOtherSide = Nothing
})
mkDuplexHandle :: FD -> Bool -> FilePath -> Bool -> IO Handle
mkDuplexHandle fd is_stream filepath binary = do
(w_buf, w_bmode) <- getBuffer fd WriteBuffer
w_spares <- newIORef BufferListNil
let w_handle_ =
Handle__ { haFD = fd,
haType = WriteHandle,
haIsBin = binary,
haIsStream = is_stream,
haBufferMode = w_bmode,
haBuffer = w_buf,
haBuffers = w_spares,
haOtherSide = Nothing
}
write_side <- newMVar w_handle_
(r_buf, r_bmode) <- getBuffer fd ReadBuffer
r_spares <- newIORef BufferListNil
let r_handle_ =
Handle__ { haFD = fd,
haType = ReadHandle,
haIsBin = binary,
haIsStream = is_stream,