{-# LANGUAGE Trustworthy #-} {-# LANGUAGE CPP , NoImplicitPrelude , RecordWildCards , BangPatterns , NondecreasingIndentation , MagicHash #-} {-# OPTIONS_GHC -Wno-unused-matches #-} {-# OPTIONS_HADDOCK not-home #-} ----------------------------------------------------------------------------- -- | -- Module : GHC.IO.Text -- Copyright : (c) The University of Glasgow, 1992-2008 -- License : see libraries/base/LICENSE -- -- Maintainer : libraries@haskell.org -- Stability : internal -- Portability : non-portable -- -- String I\/O functions -- ----------------------------------------------------------------------------- module GHC.IO.Handle.Text ( hWaitForInput, hGetChar, hGetLine, hGetContents, hPutChar, hPutStr, commitBuffer', -- hack, see below hGetBuf, hGetBufSome, hGetBufNonBlocking, hPutBuf, hPutBufNonBlocking, memcpy, hPutStrLn, hGetContents', ) where import GHC.IO import GHC.IO.Buffer import qualified GHC.IO.BufferedIO as Buffered import GHC.IO.Exception import GHC.Exception import GHC.IO.Handle.Types import GHC.IO.Handle.Internals import qualified GHC.IO.Device as IODevice import qualified GHC.IO.Device as RawIO import Foreign import Foreign.C import qualified Control.Exception as Exception import System.IO.Error import Data.Either (Either(..)) import Data.Maybe import GHC.IORef import GHC.Base import GHC.Real import GHC.Num import GHC.Show import GHC.List -- --------------------------------------------------------------------------- -- Simple input operations -- If hWaitForInput finds anything in the Handle's buffer, it -- immediately returns. If not, it tries to read from the underlying -- OS handle. Notice that for buffered Handles connected to terminals -- this means waiting until a complete line is available. -- | Computation 'hWaitForInput' @hdl t@ -- waits until input is available on handle @hdl@. -- It returns 'True' as soon as input is available on @hdl@, -- or 'False' if no input is available within @t@ milliseconds. Note that -- 'hWaitForInput' waits until one or more full /characters/ are available, -- which means that it needs to do decoding, and hence may fail -- with a decoding error. -- -- If @t@ is less than zero, then @hWaitForInput@ waits indefinitely. -- -- This operation may fail with: -- -- * 'isEOFError' if the end of file has been reached. -- -- * a decoding error, if the input begins with an invalid byte sequence -- in this Handle's encoding. -- -- NOTE for GHC users: unless you use the @-threaded@ flag, -- @hWaitForInput hdl t@ where @t >= 0@ will block all other Haskell -- threads for the duration of the call. It behaves like a -- @safe@ foreign call in this respect. -- hWaitForInput :: Handle -> Int -> IO Bool hWaitForInput h msecs = do wantReadableHandle_ "hWaitForInput" h $ \ handle_@Handle__{..} -> do cbuf <- readIORef haCharBuffer if not (isEmptyBuffer cbuf) then return True else do if msecs < 0 then do cbuf' <- readTextDevice handle_ cbuf writeIORef haCharBuffer cbuf' return True else do -- there might be bytes in the byte buffer waiting to be decoded cbuf' <- decodeByteBuf handle_ cbuf writeIORef haCharBuffer cbuf' if not (isEmptyBuffer cbuf') then return True else do r <- IODevice.ready haDevice False{-read-} msecs if r then do -- Call hLookAhead' to throw an EOF -- exception if appropriate _ <- hLookAhead_ handle_ return True else return False -- XXX we should only return when there are full characters -- not when there are only bytes. That would mean looping -- and re-running IODevice.ready if we don't have any full -- characters; but we don't know how long we've waited -- so far. -- --------------------------------------------------------------------------- -- hGetChar -- | Computation 'hGetChar' @hdl@ reads a character from the file or -- channel managed by @hdl@, blocking until a character is available. -- -- This operation may fail with: -- -- * 'isEOFError' if the end of file has been reached. hGetChar :: Handle -> IO Char hGetChar handle = wantReadableHandle_ "hGetChar" handle $ \handle_@Handle__{..} -> do -- buffering mode makes no difference: we just read whatever is available -- from the device (blocking only if there is nothing available), and then -- return the first character. -- See [note Buffered Reading] in GHC.IO.Handle.Types buf0 <- readIORef haCharBuffer buf1 <- if isEmptyBuffer buf0 then readTextDevice handle_ buf0 else return buf0 (c1,i) <- readCharBuf (bufRaw buf1) (bufL buf1) let buf2 = bufferAdjustL i buf1 if haInputNL == CRLF && c1 == '\r' then do mbuf3 <- if isEmptyBuffer buf2 then maybeFillReadBuffer handle_ buf2 else return (Just buf2) case mbuf3 of -- EOF, so just return the '\r' we have Nothing -> do writeIORef haCharBuffer buf2 return '\r' Just buf3 -> do (c2,i2) <- readCharBuf (bufRaw buf2) (bufL buf2) if c2 == '\n' then do writeIORef haCharBuffer (bufferAdjustL i2 buf3) return '\n' else do -- not a \r\n sequence, so just return the \r writeIORef haCharBuffer buf3 return '\r' else do writeIORef haCharBuffer buf2 return c1 -- --------------------------------------------------------------------------- -- hGetLine -- | Computation 'hGetLine' @hdl@ reads a line from the file or -- channel managed by @hdl@. -- -- This operation may fail with: -- -- * 'isEOFError' if the end of file is encountered when reading -- the /first/ character of the line. -- -- If 'hGetLine' encounters end-of-file at any other point while reading -- in a line, it is treated as a line terminator and the (partial) -- line is returned. hGetLine :: Handle -> IO String hGetLine h = wantReadableHandle_ "hGetLine" h $ \ handle_ -> do hGetLineBuffered handle_ hGetLineBuffered :: Handle__ -> IO String hGetLineBuffered handle_@Handle__{..} = do buf <- readIORef haCharBuffer hGetLineBufferedLoop handle_ buf [] hGetLineBufferedLoop :: Handle__ -> CharBuffer -> [String] -> IO String hGetLineBufferedLoop handle_@Handle__{..} buf@Buffer{ bufL=r0, bufR=w, bufRaw=raw0 } xss = let -- find the end-of-line character, if there is one loop raw r | r == w = return (False, w) | otherwise = do (c,r') <- readCharBuf raw r if c == '\n' then return (True, r) -- NB. not r': don't include the '\n' else loop raw r' in do (eol, off) <- loop raw0 r0 debugIO ("hGetLineBufferedLoop: r=" ++ show r0 ++ ", w=" ++ show w ++ ", off=" ++ show off) (xs,r') <- if haInputNL == CRLF then unpack_nl raw0 r0 off "" else do xs <- unpack raw0 r0 off "" return (xs,off) -- if eol == True, then off is the offset of the '\n' -- otherwise off == w and the buffer is now empty. if eol -- r' == off then do writeIORef haCharBuffer (bufferAdjustL (off+1) buf) return (concat (reverse (xs:xss))) else do let buf1 = bufferAdjustL r' buf maybe_buf <- maybeFillReadBuffer handle_ buf1 case maybe_buf of -- Nothing indicates we caught an EOF, and we may have a -- partial line to return. Nothing -> do -- we reached EOF. There might be a lone \r left -- in the buffer, so check for that and -- append it to the line if necessary. -- let pre = if not (isEmptyBuffer buf1) then "\r" else "" writeIORef haCharBuffer buf1{ bufL=0, bufR=0 } let str = concat (reverse (pre:xs:xss)) if not (null str) then return str else ioe_EOF Just new_buf -> hGetLineBufferedLoop handle_ new_buf (xs:xss) maybeFillReadBuffer :: Handle__ -> CharBuffer -> IO (Maybe CharBuffer) maybeFillReadBuffer handle_ buf = catchException (do buf' <- getSomeCharacters handle_ buf return (Just buf') ) (\e -> do if isEOFError e then return Nothing else ioError e) -- See GHC.IO.Buffer #define CHARBUF_UTF32 -- #define CHARBUF_UTF16 -- NB. performance-critical code: eyeball the Core. unpack :: RawCharBuffer -> Int -> Int -> [Char] -> IO [Char] unpack !buf !r !w acc0 | r == w = return acc0 | otherwise = withRawBuffer buf $ \pbuf -> let unpackRB acc !i | i < r = return acc | otherwise = do -- Here, we are rather careful to only put an *evaluated* character -- in the output string. Due to pointer tagging, this allows the consumer -- to avoid ping-ponging between the actual consumer code and the thunk code #if defined(CHARBUF_UTF16) -- reverse-order decoding of UTF-16 c2 <- peekElemOff pbuf i if (c2 < 0xdc00 || c2 > 0xdffff) then unpackRB (unsafeChr (fromIntegral c2) : acc) (i-1) else do c1 <- peekElemOff pbuf (i-1) let c = (fromIntegral c1 - 0xd800) * 0x400 + (fromIntegral c2 - 0xdc00) + 0x10000 case desurrogatifyRoundtripCharacter (unsafeChr c) of { C# c# -> unpackRB (C# c# : acc) (i-2) } #else c <- peekElemOff pbuf i unpackRB (c : acc) (i-1) #endif in unpackRB acc0 (w-1) -- NB. performance-critical code: eyeball the Core. unpack_nl :: RawCharBuffer -> Int -> Int -> [Char] -> IO ([Char],Int) unpack_nl !buf !r !w acc0 | r == w = return (acc0, 0) | otherwise = withRawBuffer buf $ \pbuf -> let unpackRB acc !i | i < r = return acc | otherwise = do c <- peekElemOff pbuf i if (c == '\n' && i > r) then do c1 <- peekElemOff pbuf (i-1) if (c1 == '\r') then unpackRB ('\n':acc) (i-2) else unpackRB ('\n':acc) (i-1) else do unpackRB (c : acc) (i-1) in do c <- peekElemOff pbuf (w-1) if (c == '\r') then do -- If the last char is a '\r', we need to know whether or -- not it is followed by a '\n', so leave it in the buffer -- for now and just unpack the rest. str <- unpackRB acc0 (w-2) return (str, w-1) else do str <- unpackRB acc0 (w-1) return (str, w) -- Note [#5536] -- -- We originally had -- -- let c' = desurrogatifyRoundtripCharacter c in -- c' `seq` unpackRB (c':acc) (i-1) -- -- but this resulted in Core like -- -- case (case x <# y of True -> C# e1; False -> C# e2) of c -- C# _ -> unpackRB (c:acc) (i-1) -- -- which compiles into a continuation for the outer case, with each -- branch of the inner case building a C# and then jumping to the -- continuation. We'd rather not have this extra jump, which makes -- quite a difference to performance (see #5536) It turns out that -- matching on the C# directly causes GHC to do the case-of-case, -- giving much straighter code. -- ----------------------------------------------------------------------------- -- hGetContents -- hGetContents on a DuplexHandle only affects the read side: you can -- carry on writing to it afterwards. -- | Computation 'hGetContents' @hdl@ returns the list of characters -- corresponding to the unread portion of the channel or file managed -- by @hdl@, which is put into an intermediate state, /semi-closed/. -- In this state, @hdl@ is effectively closed, -- but items are read from @hdl@ on demand and accumulated in a special -- list returned by 'hGetContents' @hdl@. -- -- Any operation that fails because a handle is closed, -- also fails if a handle is semi-closed. The only exception is -- 'System.IO.hClose'. A semi-closed handle becomes closed: -- -- * if 'System.IO.hClose' is applied to it; -- -- * if an I\/O error occurs when reading an item from the handle; -- -- * or once the entire contents of the handle has been read. -- -- Once a semi-closed handle becomes closed, the contents of the -- associated list becomes fixed. The contents of this final list is -- only partially specified: it will contain at least all the items of -- the stream that were evaluated prior to the handle becoming closed. -- -- Any I\/O errors encountered while a handle is semi-closed are simply -- discarded. -- -- This operation may fail with: -- -- * 'isEOFError' if the end of file has been reached. hGetContents :: Handle -> IO String hGetContents handle = wantReadableHandle "hGetContents" handle $ \handle_ -> do xs <- lazyRead handle return (handle_{ haType=SemiClosedHandle}, xs ) -- Note that someone may close the semi-closed handle (or change its -- buffering), so each time these lazy read functions are pulled on, -- they have to check whether the handle has indeed been closed. lazyRead :: Handle -> IO String lazyRead handle = unsafeInterleaveIO $ withHandle "hGetContents" handle $ \ handle_ -> do case haType handle_ of SemiClosedHandle -> lazyReadBuffered handle handle_ ClosedHandle -> ioException (IOError (Just handle) IllegalOperation "hGetContents" "delayed read on closed handle" Nothing Nothing) _ -> ioException (IOError (Just handle) IllegalOperation "hGetContents" "illegal handle type" Nothing Nothing) lazyReadBuffered :: Handle -> Handle__ -> IO (Handle__, [Char]) lazyReadBuffered h handle_@Handle__{..} = do buf <- readIORef haCharBuffer Exception.catch (do buf'@Buffer{..} <- getSomeCharacters handle_ buf lazy_rest <- lazyRead h (s,r) <- if haInputNL == CRLF then unpack_nl bufRaw bufL bufR lazy_rest else do s <- unpack bufRaw bufL bufR lazy_rest return (s,bufR) writeIORef haCharBuffer (bufferAdjustL r buf') return (handle_, s) ) (\e -> do (handle_', _) <- hClose_help handle_ debugIO ("hGetContents caught: " ++ show e) -- We might have a \r cached in CRLF mode. So we -- need to check for that and return it: let r = if isEOFError e then if not (isEmptyBuffer buf) then "\r" else "" else throw (augmentIOError e "hGetContents" h) return (handle_', r) ) -- ensure we have some characters in the buffer getSomeCharacters :: Handle__ -> CharBuffer -> IO CharBuffer getSomeCharacters handle_@Handle__{..} buf@Buffer{..} = case bufferElems buf of -- buffer empty: read some more 0 -> readTextDevice handle_ buf -- if the buffer has a single '\r' in it and we're doing newline -- translation: read some more 1 | haInputNL == CRLF -> do (c,_) <- readCharBuf bufRaw bufL if c == '\r' then do -- shuffle the '\r' to the beginning. This is only safe -- if we're about to call readTextDevice, otherwise it -- would mess up flushCharBuffer. -- See [note Buffer Flushing], GHC.IO.Handle.Types _ <- writeCharBuf bufRaw 0 '\r' let buf' = buf{ bufL=0, bufR=1 } readTextDevice handle_ buf' else do return buf -- buffer has some chars in it already: just return it _otherwise -> return buf -- ----------------------------------------------------------------------------- -- hGetContents' -- We read everything into a list of CharBuffer chunks, and convert it lazily -- to a string, which minimizes memory usage. -- In the worst case, space usage is at most that of the complete String, -- as the chunks can be garbage collected progressively. -- For streaming consumers, space usage is at most that of the list of chunks. -- | The 'hGetContents'' operation reads all input on the given handle -- before returning it as a 'String' and closing the handle. -- -- @since 4.15.0.0 hGetContents' :: Handle -> IO String hGetContents' handle = do es <- wantReadableHandle "hGetContents'" handle (strictRead handle) case es of Right s -> return s Left e -> case fromException e of Just ioe -> throwIO (augmentIOError ioe "hGetContents'" handle) Nothing -> throwIO e strictRead :: Handle -> Handle__ -> IO (Handle__, Either SomeException String) strictRead h handle_@Handle__{..} = do cbuf <- readIORef haCharBuffer cbufs <- strictReadLoop' handle_ [] cbuf (handle_', me) <- hClose_help handle_ case me of Just e -> return (handle_', Left e) Nothing -> do s <- lazyBuffersToString haInputNL cbufs "" return (handle_', Right s) strictReadLoop :: Handle__ -> [CharBuffer] -> CharBuffer -> IO [CharBuffer] strictReadLoop handle_ cbufs cbuf0 = do mcbuf <- Exception.catch (do r <- readTextDevice handle_ cbuf0 return (Just r)) (\e -> if isEOFError e then return Nothing else throw e) case mcbuf of Nothing -> return (cbuf0 : cbufs) Just cbuf1 -> strictReadLoop' handle_ cbufs cbuf1 -- If 'cbuf' is full, allocate a new buffer. strictReadLoop' :: Handle__ -> [CharBuffer] -> CharBuffer -> IO [CharBuffer] strictReadLoop' handle_ cbufs cbuf | isFullCharBuffer cbuf = do cbuf' <- newCharBuffer dEFAULT_CHAR_BUFFER_SIZE ReadBuffer strictReadLoop handle_ (cbuf : cbufs) cbuf' | otherwise = strictReadLoop handle_ cbufs cbuf -- Lazily convert a list of buffers to a String. The buffers are -- in reverse order: the first buffer is the end of the String. lazyBuffersToString :: Newline -> [CharBuffer] -> String -> IO String lazyBuffersToString LF = loop where loop [] s = return s loop (Buffer{..} : cbufs) s = do s' <- unsafeInterleaveIO (unpack bufRaw bufL bufR s) loop cbufs s' lazyBuffersToString CRLF = loop '\0' where loop before [] s = return s loop before (Buffer{..} : cbufs) s | bufL == bufR = loop before cbufs s -- skip empty buffers | otherwise = do -- When a CRLF is broken across two buffers, we already have a newline -- from decoding the LF, so we ignore the CR in the current buffer. s1 <- if before == '\n' then return s else do -- We restore trailing CR not followed by LF. c <- peekCharBuf bufRaw (bufR - 1) if c == '\r' then return ('\r' : s) else return s s2 <- unsafeInterleaveIO (do (s2, _) <- unpack_nl bufRaw bufL bufR s1 return s2) c0 <- peekCharBuf bufRaw bufL loop c0 cbufs s2 -- --------------------------------------------------------------------------- -- hPutChar -- | Computation 'hPutChar' @hdl ch@ writes the character @ch@ to the -- file or channel managed by @hdl@. Characters may be buffered if -- buffering is enabled for @hdl@. -- -- This operation may fail with: -- -- * 'isFullError' if the device is full; or -- -- * 'isPermissionError' if another system resource limit would be exceeded. hPutChar :: Handle -> Char -> IO () hPutChar handle c = do c `seq` return () wantWritableHandle "hPutChar" handle $ \ handle_ -> do hPutcBuffered handle_ c hPutcBuffered :: Handle__ -> Char -> IO () hPutcBuffered handle_@Handle__{..} c = do buf <- readIORef haCharBuffer if c == '\n' then do buf1 <- if haOutputNL == CRLF then do buf1 <- putc buf '\r' putc buf1 '\n' else do putc buf '\n' writeCharBuffer handle_ buf1 when is_line $ flushByteWriteBuffer handle_ else do buf1 <- putc buf c writeCharBuffer handle_ buf1 return () where is_line = case haBufferMode of LineBuffering -> True _ -> False putc buf@Buffer{ bufRaw=raw, bufR=w } c' = do debugIO ("putc: " ++ summaryBuffer buf) w' <- writeCharBuf raw w c' return buf{ bufR = w' } -- --------------------------------------------------------------------------- -- hPutStr -- We go to some trouble to avoid keeping the handle locked while we're -- evaluating the string argument to hPutStr, in case doing so triggers another -- I/O operation on the same handle which would lead to deadlock. The classic -- case is -- -- putStr (trace "hello" "world") -- -- so the basic scheme is this: -- -- * copy the string into a fresh buffer, -- * "commit" the buffer to the handle. -- -- Committing may involve simply copying the contents of the new -- buffer into the handle's buffer, flushing one or both buffers, or -- maybe just swapping the buffers over (if the handle's buffer was -- empty). See commitBuffer below. -- | Computation 'hPutStr' @hdl s@ writes the string -- @s@ to the file or channel managed by @hdl@. -- -- This operation may fail with: -- -- * 'isFullError' if the device is full; or -- -- * 'isPermissionError' if another system resource limit would be exceeded. hPutStr :: Handle -> String -> IO () hPutStr handle str = hPutStr' handle str False -- | The same as 'hPutStr', but adds a newline character. hPutStrLn :: Handle -> String -> IO () hPutStrLn handle str = hPutStr' handle str True -- An optimisation: we treat hPutStrLn specially, to avoid the -- overhead of a single putChar '\n', which is quite high now that we -- have to encode eagerly. {-# NOINLINE hPutStr' #-} hPutStr' :: Handle -> String -> Bool -> IO () hPutStr' handle str add_nl = do (buffer_mode, nl) <- wantWritableHandle "hPutStr" handle $ \h_ -> do bmode <- getSpareBuffer h_ return (bmode, haOutputNL h_) case buffer_mode of (NoBuffering, _) -> do hPutChars handle str -- v. slow, but we don't care when add_nl $ hPutChar handle '\n' (LineBuffering, buf) -> do writeBlocks handle True add_nl nl buf str (BlockBuffering _, buf) -> do writeBlocks handle False add_nl nl buf str hPutChars :: Handle -> [Char] -> IO () hPutChars _ [] = return () hPutChars handle (c:cs) = hPutChar handle c >> hPutChars handle cs -- Buffer offset is always zero. getSpareBuffer :: Handle__ -> IO (BufferMode, CharBuffer) getSpareBuffer Handle__{haCharBuffer=ref, haBuffers=spare_ref, haBufferMode=mode} = do case mode of NoBuffering -> return (mode, errorWithoutStackTrace "no buffer!") _ -> do bufs <- readIORef spare_ref buf <- readIORef ref case bufs of BufferListCons b rest -> do writeIORef spare_ref rest return ( mode, emptyBuffer b (bufSize buf) WriteBuffer) BufferListNil -> do new_buf <- newCharBuffer (bufSize buf) WriteBuffer return (mode, new_buf) -- NB. performance-critical code: eyeball the Core. writeBlocks :: Handle -> Bool -> Bool -> Newline -> Buffer CharBufElem -> String -> IO () writeBlocks hdl line_buffered add_nl nl buf@Buffer{ bufRaw=raw, bufSize=len } s = let shoveString :: Int -> [Char] -> [Char] -> IO () shoveString !n [] [] = do commitBuffer hdl raw len n False{-no flush-} True{-release-} shoveString !n [] rest = do shoveString n rest [] shoveString !n (c:cs) rest -- n+1 so we have enough room to write '\r\n' if necessary | n + 1 >= len = do commitBuffer hdl raw len n False{-flush-} False shoveString 0 (c:cs) rest | c == '\n' = do n' <- if nl == CRLF then do n1 <- writeCharBuf raw n '\r' writeCharBuf raw n1 '\n' else do writeCharBuf raw n c if line_buffered then do -- end of line, so write and flush commitBuffer hdl raw len n' True{-flush-} False shoveString 0 cs rest else do shoveString n' cs rest | otherwise = do n' <- writeCharBuf raw n c shoveString n' cs rest in shoveString 0 s (if add_nl then "\n" else "") -- ----------------------------------------------------------------------------- -- commitBuffer handle buf sz count flush release -- -- Write the contents of the buffer 'buf' ('sz' bytes long, containing -- 'count' bytes of data) to handle (handle must be block or line buffered). commitBuffer :: Handle -- handle to commit to -> RawCharBuffer -> Int -- address and size (in bytes) of buffer -> Int -- number of bytes of data in buffer -> Bool -- True <=> flush the handle afterward -> Bool -- release the buffer? -> IO () commitBuffer hdl !raw !sz !count flush release = wantWritableHandle "commitBuffer" hdl $ \h_@Handle__{..} -> do debugIO ("commitBuffer: sz=" ++ show sz ++ ", count=" ++ show count ++ ", flush=" ++ show flush ++ ", release=" ++ show release ++ ", handle=" ++ show hdl) -- Offset taken from handle writeCharBuffer h_ Buffer{ bufRaw=raw, bufState=WriteBuffer, bufOffset=0, bufL=0, bufR=count, bufSize=sz } when flush $ flushByteWriteBuffer h_ -- release the buffer if necessary when release $ do -- find size of current buffer old_buf@Buffer{ bufSize=size } <- readIORef haCharBuffer when (sz == size) $ do spare_bufs <- readIORef haBuffers writeIORef haBuffers (BufferListCons raw spare_bufs) -- bb <- readIORef haByteBuffer -- debugIO ("commitBuffer: buffer=" ++ summaryBuffer bb ++ ", handle=" ++ show hdl) return () -- backwards compatibility; the text package uses this commitBuffer' :: RawCharBuffer -> Int -> Int -> Bool -> Bool -> Handle__ -> IO CharBuffer commitBuffer' raw sz@(I# _) count@(I# _) flush release h_@Handle__{..} = do debugIO ("commitBuffer: sz=" ++ show sz ++ ", count=" ++ show count ++ ", flush=" ++ show flush ++ ", release=" ++ show release) let this_buf = Buffer{ bufRaw=raw, bufState=WriteBuffer, bufL=0, bufR=count, bufSize=sz, bufOffset=0 } writeCharBuffer h_ this_buf when flush $ flushByteWriteBuffer h_ -- release the buffer if necessary when release $ do -- find size of current buffer old_buf@Buffer{ bufSize=size } <- readIORef haCharBuffer when (sz == size) $ do spare_bufs <- readIORef haBuffers writeIORef haBuffers (BufferListCons raw spare_bufs) return this_buf -- --------------------------------------------------------------------------- -- Reading/writing sequences of bytes. -- --------------------------------------------------------------------------- -- hPutBuf -- | 'hPutBuf' @hdl buf count@ writes @count@ 8-bit bytes from the -- buffer @buf@ to the handle @hdl@. It returns (). -- -- 'hPutBuf' ignores any text encoding that applies to the 'Handle', -- writing the bytes directly to the underlying file or device. -- -- 'hPutBuf' ignores the prevailing 'System.IO.TextEncoding' and -- 'NewlineMode' on the 'Handle', and writes bytes directly. -- -- This operation may fail with: -- -- * 'ResourceVanished' if the handle is a pipe or socket, and the -- reading end is closed. (If this is a POSIX system, and the program -- has not asked to ignore SIGPIPE, then a SIGPIPE may be delivered -- instead, whose default action is to terminate the program). hPutBuf :: Handle -- handle to write to -> Ptr a -- address of buffer -> Int -- number of bytes of data in buffer -> IO () hPutBuf h ptr count = do _ <- hPutBuf' h ptr count True return () hPutBufNonBlocking :: Handle -- handle to write to -> Ptr a -- address of buffer -> Int -- number of bytes of data in buffer -> IO Int -- returns: number of bytes written hPutBufNonBlocking h ptr count = hPutBuf' h ptr count False hPutBuf':: Handle -- handle to write to -> Ptr a -- address of buffer -> Int -- number of bytes of data in buffer -> Bool -- allow blocking? -> IO Int hPutBuf' handle ptr count can_block | count == 0 = return 0 | count < 0 = illegalBufferSize handle "hPutBuf" count | otherwise = wantWritableHandle "hPutBuf" handle $ \ h_@Handle__{..} -> do debugIO ("hPutBuf count=" ++ show count) r <- bufWrite h_ (castPtr ptr) count can_block -- we must flush if this Handle is set to NoBuffering. If -- it is set to LineBuffering, be conservative and flush -- anyway (we didn't check for newlines in the data). case haBufferMode of BlockBuffering _ -> do return () _line_or_no_buffering -> do flushWriteBuffer h_ return r -- TODO: Possible optimisation: -- If we know that `w + count > size`, we should write both the -- handle buffer and the `ptr` in a single `writev()` syscall. bufWrite :: Handle__-> Ptr Word8 -> Int -> Bool -> IO Int bufWrite h_@Handle__{..} ptr !count can_block = do -- Get buffer to determine size and free space in buffer old_buf@Buffer{ bufR=w, bufSize=size } <- readIORef haByteBuffer -- There's no need to buffer if the incoming data is larger than -- the handle buffer (`count >= size`). -- Check if we can try to buffer the given chunk of data. b <- if (count < size && count <= size - w) then bufferChunk h_ old_buf ptr count else do -- The given data does not fit into the buffer. -- Either because it's too large for the buffer -- or the buffer is too full. Either way we need -- to flush the buffered data first. flushed_buf <- flushByteWriteBufferGiven h_ old_buf if count < size -- The data is small enough to be buffered. then bufferChunk h_ flushed_buf ptr count else do let offset = bufOffset flushed_buf !bytes <- if can_block then do writeChunk h_ (castPtr ptr) offset count else writeChunkNonBlocking h_ (castPtr ptr) offset count -- Update buffer with actual bytes written. writeIORef haByteBuffer $! bufferAddOffset bytes flushed_buf return bytes debugIO "hPutBuf: done" return b -- Flush the given buffer via the handle, return the flushed buffer flushByteWriteBufferGiven :: Handle__ -> Buffer Word8 -> IO (Buffer Word8) flushByteWriteBufferGiven h_@Handle__{..} bbuf = do if (not (isEmptyBuffer bbuf)) then do bbuf' <- Buffered.flushWriteBuffer haDevice bbuf debugIO ("flushByteWriteBufferGiven: bbuf=" ++ summaryBuffer bbuf') writeIORef haByteBuffer bbuf' return bbuf' else return bbuf -- Fill buffer and return bytes buffered/written. -- Flushes buffer if it's full after adding the data. bufferChunk :: Handle__ -> Buffer Word8 -> Ptr Word8 -> Int -> IO Int bufferChunk h_@Handle__{..} old_buf@Buffer{ bufRaw=raw, bufR=w, bufSize=size } ptr !count = do debugIO ("hPutBuf: copying to buffer, w=" ++ show w) copyToRawBuffer raw w ptr count let copied_buf = old_buf{ bufR = w + count } -- If the write filled the buffer completely, we need to flush, -- to maintain the "INVARIANTS on Buffers" from -- GHC.IO.Buffer.checkBuffer: "a write buffer is never full". if isFullBuffer copied_buf then do -- TODO: we should do a non-blocking flush here debugIO "hPutBuf: flushing full buffer after writing" _ <- flushByteWriteBufferGiven h_ copied_buf return () else do writeIORef haByteBuffer copied_buf return count writeChunk :: Handle__ -> Ptr Word8 -> Word64 -> Int -> IO Int writeChunk h_@Handle__{..} ptr offset bytes = do RawIO.write haDevice ptr offset bytes return bytes writeChunkNonBlocking :: Handle__ -> Ptr Word8 -> Word64 -> Int -> IO Int writeChunkNonBlocking h_@Handle__{..} ptr offset bytes = RawIO.writeNonBlocking haDevice ptr offset bytes -- --------------------------------------------------------------------------- -- hGetBuf -- | 'hGetBuf' @hdl buf count@ reads data from the handle @hdl@ -- into the buffer @buf@ until either EOF is reached or -- @count@ 8-bit bytes have been read. -- It returns the number of bytes actually read. This may be zero if -- EOF was reached before any data was read (or if @count@ is zero). -- -- 'hGetBuf' never raises an EOF exception, instead it returns a value -- smaller than @count@. -- -- If the handle is a pipe or socket, and the writing end -- is closed, 'hGetBuf' will behave as if EOF was reached. -- -- 'hGetBuf' ignores the prevailing 'System.IO.TextEncoding' and 'NewlineMode' -- on the 'Handle', and reads bytes directly. hGetBuf :: Handle -> Ptr a -> Int -> IO Int hGetBuf h !ptr count | count == 0 = return 0 | count < 0 = illegalBufferSize h "hGetBuf" count | otherwise = wantReadableHandle_ "hGetBuf" h $ \ h_@Handle__{..} -> do debugIO $ ":: hGetBuf - " ++ show h ++ " - " ++ show count flushCharReadBuffer h_ buf@Buffer{ bufRaw=raw, bufR=w, bufL=r, bufSize=sz } <- readIORef haByteBuffer debugIO ("hGetBuf: " ++ summaryBuffer buf) res <- if isEmptyBuffer buf then bufReadEmpty h_ buf (castPtr ptr) 0 count else bufReadNonEmpty h_ buf (castPtr ptr) 0 count debugIO "** hGetBuf done." return res -- small reads go through the buffer, large reads are satisfied by -- taking data first from the buffer and then direct from the file -- descriptor. bufReadNonEmpty :: Handle__ -> Buffer Word8 -> Ptr Word8 -> Int -> Int -> IO Int bufReadNonEmpty h_@Handle__{..} -- w for width, r for ... read ptr? buf@Buffer{ bufRaw=raw, bufR=w, bufL=r, bufSize=sz } ptr !so_far !count = do debugIO ":: bufReadNonEmpty" -- We use < instead of <= because for count == avail -- we need to reset bufL and bufR to zero. -- See also: INVARIANTS on Buffers let avail = w - r if (count < avail) then do copyFromRawBuffer ptr raw r count writeIORef haByteBuffer buf{ bufL = r + count } return (so_far + count) else do copyFromRawBuffer ptr raw r avail let buf' = buf{ bufR=0, bufL=0 } writeIORef haByteBuffer buf' let remaining = count - avail so_far' = so_far + avail ptr' = ptr `plusPtr` avail debugIO ("bufReadNonEmpty: " ++ summaryBuffer buf' ++ " s:" ++ show so_far' ++ " r:" ++ show remaining) b <- if remaining == 0 then return so_far' else bufReadEmpty h_ buf' ptr' so_far' remaining debugIO ":: bufReadNonEmpty - done" return b -- We want to read more data, but the buffer is empty. (buffL == buffR == 0) -- See also Note [INVARIANTS on Buffers] in Buffer.hs bufReadEmpty :: Handle__ -> Buffer Word8 -> Ptr Word8 -> Int -> Int -> IO Int bufReadEmpty h_@Handle__{..} buf@Buffer{ bufRaw=raw, bufR=w, bufL=_r, bufSize=sz, bufOffset=bff } ptr so_far count | count > sz = do bytes_read <- loop haDevice 0 bff count -- bytes_read includes so_far (content that was in the buffer) -- but that is already accounted for in the old offset, so don't -- count it twice. let buf1 = bufferAddOffset (fromIntegral $ bytes_read - so_far) buf writeIORef haByteBuffer buf1 debugIO ("bufReadEmpty1.1: " ++ summaryBuffer buf1 ++ " read:" ++ show bytes_read) return bytes_read | otherwise = do (r,buf') <- Buffered.fillReadBuffer haDevice buf writeIORef haByteBuffer buf' if r == 0 -- end of file reached then return so_far else bufReadNonEmpty h_ buf' ptr so_far count where -- Read @bytes@ byte into ptr. Repeating the read until either zero -- bytes where read, or we are done reading. loop :: RawIO.RawIO dev => dev -> Int -> Word64 -> Int -> IO Int loop dev delta off bytes | bytes <= 0 = return (so_far + delta) loop dev delta off bytes = do r <- RawIO.read dev (ptr `plusPtr` delta) off bytes debugIO $ show ptr ++ " - loop read@" ++ show delta ++ ": " ++ show r debugIO $ "next:" ++ show (delta + r) ++ " - left:" ++ show (bytes - r) if r == 0 then return (so_far + delta) else loop dev (delta + r) (off + fromIntegral r) (bytes - r) -- --------------------------------------------------------------------------- -- hGetBufSome -- | 'hGetBufSome' @hdl buf count@ reads data from the handle @hdl@ -- into the buffer @buf@. If there is any data available to read, -- then 'hGetBufSome' returns it immediately; it only blocks if there -- is no data to be read. -- -- It returns the number of bytes actually read. This may be zero if -- EOF was reached before any data was read (or if @count@ is zero). -- -- 'hGetBufSome' never raises an EOF exception, instead it returns a value -- smaller than @count@. -- -- If the handle is a pipe or socket, and the writing end -- is closed, 'hGetBufSome' will behave as if EOF was reached. -- -- 'hGetBufSome' ignores the prevailing 'System.IO.TextEncoding' and -- 'NewlineMode' on the 'Handle', and reads bytes directly. hGetBufSome :: Handle -> Ptr a -> Int -> IO Int hGetBufSome h !ptr count | count == 0 = return 0 | count < 0 = illegalBufferSize h "hGetBufSome" count | otherwise = wantReadableHandle_ "hGetBufSome" h $ \ h_@Handle__{..} -> do flushCharReadBuffer h_ buf@Buffer{ bufSize=sz, bufOffset=offset } <- readIORef haByteBuffer if isEmptyBuffer buf then case count > sz of -- large read? optimize it with a little special case: True -> do bytes <- RawIO.read haDevice (castPtr ptr) offset count -- Update buffer with actual bytes written. writeIORef haByteBuffer $! bufferAddOffset bytes buf return bytes _ -> do (r,buf') <- Buffered.fillReadBuffer haDevice buf if r == 0 then return 0 else do writeIORef haByteBuffer buf' bufReadNBNonEmpty h_ buf' (castPtr ptr) 0 (min r count) -- new count is (min r count), so -- that bufReadNBNonEmpty will not -- issue another read. else let count' = min count (bufferElems buf) in bufReadNBNonEmpty h_ buf (castPtr ptr) 0 count' -- | 'hGetBufNonBlocking' @hdl buf count@ reads data from the handle @hdl@ -- into the buffer @buf@ until either EOF is reached, or -- @count@ 8-bit bytes have been read, or there is no more data available -- to read immediately. -- -- 'hGetBufNonBlocking' is identical to 'hGetBuf', except that it will -- never block waiting for data to become available, instead it returns -- only whatever data is available. To wait for data to arrive before -- calling 'hGetBufNonBlocking', use 'hWaitForInput'. -- -- If the handle is a pipe or socket, and the writing end -- is closed, 'hGetBufNonBlocking' will behave as if EOF was reached. -- -- 'hGetBufNonBlocking' ignores the prevailing 'System.IO.TextEncoding' and -- 'NewlineMode' on the 'Handle', and reads bytes directly. -- -- NOTE: on Windows, this function does not work correctly; it -- behaves identically to 'hGetBuf'. hGetBufNonBlocking :: Handle -> Ptr a -> Int -> IO Int hGetBufNonBlocking h !ptr count | count == 0 = return 0 | count < 0 = illegalBufferSize h "hGetBufNonBlocking" count | otherwise = wantReadableHandle_ "hGetBufNonBlocking" h $ \ h_@Handle__{..} -> do flushCharReadBuffer h_ buf@Buffer{ bufRaw=raw, bufR=w, bufL=r, bufSize=sz } <- readIORef haByteBuffer if isEmptyBuffer buf then bufReadNBEmpty h_ buf (castPtr ptr) 0 count else bufReadNBNonEmpty h_ buf (castPtr ptr) 0 count bufReadNBEmpty :: Handle__ -> Buffer Word8 -> Ptr Word8 -> Int -> Int -> IO Int bufReadNBEmpty h_@Handle__{..} buf@Buffer{ bufRaw=raw, bufR=w, bufL=_r, bufSize=sz , bufOffset=offset } ptr so_far count | count > sz = do m <- RawIO.readNonBlocking haDevice ptr offset count case m of Nothing -> return so_far Just n -> do -- Update buffer with actual bytes written. writeIORef haByteBuffer $! bufferAddOffset n buf return (so_far + n) | otherwise = do -- buf <- readIORef haByteBuffer (r,buf') <- Buffered.fillReadBuffer0 haDevice buf case r of Nothing -> return so_far Just 0 -> return so_far Just r' -> do writeIORef haByteBuffer buf' bufReadNBNonEmpty h_ buf' ptr so_far (min count r') -- NOTE: new count is min count r' -- so we will just copy the contents of the -- buffer in the recursive call, and not -- loop again. bufReadNBNonEmpty :: Handle__ -> Buffer Word8 -> Ptr Word8 -> Int -> Int -> IO Int bufReadNBNonEmpty h_@Handle__{..} buf@Buffer{ bufRaw=raw, bufR=w, bufL=r, bufSize=sz } ptr so_far count = do let avail = w - r -- We use < instead of <= because for count == avail -- we need to reset bufL and bufR to zero. -- See also [INVARIANTS on Buffers] in Buffer.hs if (count < avail) then do copyFromRawBuffer ptr raw r count writeIORef haByteBuffer buf{ bufL = r + count } return (so_far + count) else do copyFromRawBuffer ptr raw r avail let buf' = buf{ bufR=0, bufL=0 } writeIORef haByteBuffer buf' let remaining = count - avail so_far' = so_far + avail ptr' = ptr `plusPtr` avail if remaining == 0 then return so_far' else bufReadNBEmpty h_ buf' ptr' so_far' remaining -- --------------------------------------------------------------------------- -- memcpy wrappers copyToRawBuffer :: RawBuffer e -> Int -> Ptr e -> Int -> IO () copyToRawBuffer raw off ptr bytes = withRawBuffer raw $ \praw -> do _ <- memcpy (praw `plusPtr` off) ptr (fromIntegral bytes) return () copyFromRawBuffer :: Ptr e -> RawBuffer e -> Int -> Int -> IO () copyFromRawBuffer ptr raw off bytes = withRawBuffer raw $ \praw -> do _ <- memcpy ptr (praw `plusPtr` off) (fromIntegral bytes) return () foreign import ccall unsafe "memcpy" memcpy :: Ptr a -> Ptr a -> CSize -> IO (Ptr ()) ----------------------------------------------------------------------------- -- Internal Utils illegalBufferSize :: Handle -> String -> Int -> IO a illegalBufferSize handle fn sz = ioException (IOError (Just handle) InvalidArgument fn ("illegal buffer size " ++ showsPrec 9 sz []) Nothing Nothing)