X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=System%2FIO.hs;h=bf26835eef628b0335ae9246723e0852295577aa;hb=HEAD;hp=cebaa9846b2af50f02eb8423aa9b6945f4021a75;hpb=6dd66061e863deb0d526e8680a2735f1b4d5aa2d;p=ghc-base.git diff --git a/System/IO.hs b/System/IO.hs index cebaa98..bf26835 100644 --- a/System/IO.hs +++ b/System/IO.hs @@ -1,4 +1,5 @@ -{-# OPTIONS_GHC -fno-implicit-prelude #-} +{-# LANGUAGE CPP, NoImplicitPrelude #-} + ----------------------------------------------------------------------------- -- | -- Module : System.IO @@ -16,14 +17,23 @@ module System.IO ( -- * The IO monad - IO, -- instance MonadFix - fixIO, -- :: (a -> IO a) -> IO a + IO, -- instance MonadFix + fixIO, -- :: (a -> IO a) -> IO a -- * Files and handles - FilePath, -- :: String + FilePath, -- :: String + + Handle, -- abstract, instance of: Eq, Show. - Handle, -- abstract, instance of: Eq, Show. + -- | GHC note: a 'Handle' will be automatically closed when the garbage + -- collector detects that it has become unreferenced by the program. + -- However, relying on this behaviour is not generally recommended: + -- the garbage collector is unpredictable. If possible, use + -- an explicit 'hClose' to close 'Handle's when they are no longer + -- required. GHC does not currently attempt to free up file + -- descriptors when they have run out, it is your responsibility to + -- ensure that this doesn't happen. -- ** Standard handles @@ -37,20 +47,20 @@ module System.IO ( -- ** Opening files withFile, - openFile, -- :: FilePath -> IOMode -> IO Handle + openFile, -- :: FilePath -> IOMode -> IO Handle IOMode(ReadMode,WriteMode,AppendMode,ReadWriteMode), -- ** Closing files - hClose, -- :: Handle -> IO () + hClose, -- :: Handle -> IO () -- ** Special cases -- | These functions are also exported by the "Prelude". - readFile, -- :: FilePath -> IO String - writeFile, -- :: FilePath -> String -> IO () - appendFile, -- :: FilePath -> String -> IO () + readFile, -- :: FilePath -> IO String + writeFile, -- :: FilePath -> String -> IO () + appendFile, -- :: FilePath -> String -> IO () -- ** File locking @@ -60,33 +70,33 @@ module System.IO ( -- ** Determining and changing the size of a file - hFileSize, -- :: Handle -> IO Integer + hFileSize, -- :: Handle -> IO Integer #ifdef __GLASGOW_HASKELL__ hSetFileSize, -- :: Handle -> Integer -> IO () #endif -- ** Detecting the end of input - hIsEOF, -- :: Handle -> IO Bool - isEOF, -- :: IO Bool + hIsEOF, -- :: Handle -> IO Bool + isEOF, -- :: IO Bool -- ** Buffering operations BufferMode(NoBuffering,LineBuffering,BlockBuffering), - hSetBuffering, -- :: Handle -> BufferMode -> IO () - hGetBuffering, -- :: Handle -> IO BufferMode - hFlush, -- :: Handle -> IO () + hSetBuffering, -- :: Handle -> BufferMode -> IO () + hGetBuffering, -- :: Handle -> IO BufferMode + hFlush, -- :: Handle -> IO () -- ** Repositioning handles - hGetPosn, -- :: Handle -> IO HandlePosn - hSetPosn, -- :: HandlePosn -> IO () + hGetPosn, -- :: Handle -> IO HandlePosn + hSetPosn, -- :: HandlePosn -> IO () HandlePosn, -- abstract, instance of: Eq, Show. - hSeek, -- :: Handle -> SeekMode -> Integer -> IO () + hSeek, -- :: Handle -> SeekMode -> Integer -> IO () SeekMode(AbsoluteSeek,RelativeSeek,SeekFromEnd), #if !defined(__NHC__) - hTell, -- :: Handle -> IO Integer + hTell, -- :: Handle -> IO Integer #endif -- ** Handle properties @@ -95,82 +105,158 @@ module System.IO ( hIsReadable, hIsWritable, -- :: Handle -> IO Bool hIsSeekable, -- :: Handle -> IO Bool - -- ** Terminal operations + -- ** Terminal operations (not portable: GHC\/Hugs only) #if !defined(__NHC__) - hIsTerminalDevice, -- :: Handle -> IO Bool + hIsTerminalDevice, -- :: Handle -> IO Bool - hSetEcho, -- :: Handle -> Bool -> IO () - hGetEcho, -- :: Handle -> IO Bool + hSetEcho, -- :: Handle -> Bool -> IO () + hGetEcho, -- :: Handle -> IO Bool #endif - -- ** Showing handle state + -- ** Showing handle state (not portable: GHC only) #ifdef __GLASGOW_HASKELL__ - hShow, -- :: Handle -> IO String + hShow, -- :: Handle -> IO String #endif -- * Text input and output -- ** Text input - hWaitForInput, -- :: Handle -> Int -> IO Bool - hReady, -- :: Handle -> IO Bool - hGetChar, -- :: Handle -> IO Char - hGetLine, -- :: Handle -> IO [Char] - hLookAhead, -- :: Handle -> IO Char - hGetContents, -- :: Handle -> IO [Char] + hWaitForInput, -- :: Handle -> Int -> IO Bool + hReady, -- :: Handle -> IO Bool + hGetChar, -- :: Handle -> IO Char + hGetLine, -- :: Handle -> IO [Char] + hLookAhead, -- :: Handle -> IO Char + hGetContents, -- :: Handle -> IO [Char] -- ** Text output - hPutChar, -- :: Handle -> Char -> IO () - hPutStr, -- :: Handle -> [Char] -> IO () - hPutStrLn, -- :: Handle -> [Char] -> IO () - hPrint, -- :: Show a => Handle -> a -> IO () + hPutChar, -- :: Handle -> Char -> IO () + hPutStr, -- :: Handle -> [Char] -> IO () + hPutStrLn, -- :: Handle -> [Char] -> IO () + hPrint, -- :: Show a => Handle -> a -> IO () -- ** Special cases for standard input and output -- | These functions are also exported by the "Prelude". - interact, -- :: (String -> String) -> IO () - putChar, -- :: Char -> IO () - putStr, -- :: String -> IO () - putStrLn, -- :: String -> IO () - print, -- :: Show a => a -> IO () - getChar, -- :: IO Char - getLine, -- :: IO String - getContents, -- :: IO String - readIO, -- :: Read a => String -> IO a - readLn, -- :: Read a => IO a + interact, -- :: (String -> String) -> IO () + putChar, -- :: Char -> IO () + putStr, -- :: String -> IO () + putStrLn, -- :: String -> IO () + print, -- :: Show a => a -> IO () + getChar, -- :: IO Char + getLine, -- :: IO String + getContents, -- :: IO String + readIO, -- :: Read a => String -> IO a + readLn, -- :: Read a => IO a -- * Binary input and output withBinaryFile, - openBinaryFile, -- :: FilePath -> IOMode -> IO Handle - hSetBinaryMode, -- :: Handle -> Bool -> IO () - hPutBuf, -- :: Handle -> Ptr a -> Int -> IO () - hGetBuf, -- :: Handle -> Ptr a -> Int -> IO Int + openBinaryFile, -- :: FilePath -> IOMode -> IO Handle + hSetBinaryMode, -- :: Handle -> Bool -> IO () + hPutBuf, -- :: Handle -> Ptr a -> Int -> IO () + hGetBuf, -- :: Handle -> Ptr a -> Int -> IO Int #if !defined(__NHC__) && !defined(__HUGS__) - hPutBufNonBlocking, -- :: Handle -> Ptr a -> Int -> IO Int - hGetBufNonBlocking, -- :: Handle -> Ptr a -> Int -> IO Int + hGetBufSome, -- :: Handle -> Ptr a -> Int -> IO Int + hPutBufNonBlocking, -- :: Handle -> Ptr a -> Int -> IO Int + hGetBufNonBlocking, -- :: Handle -> Ptr a -> Int -> IO Int #endif -- * Temporary files -#ifdef __GLASGOW_HASKELL__ openTempFile, openBinaryTempFile, + openTempFileWithDefaultPermissions, + openBinaryTempFileWithDefaultPermissions, + +#if !defined(__NHC__) && !defined(__HUGS__) + -- * Unicode encoding\/decoding + + -- | A text-mode 'Handle' has an associated 'TextEncoding', which + -- is used to decode bytes into Unicode characters when reading, + -- and encode Unicode characters into bytes when writing. + -- + -- The default 'TextEncoding' is the same as the default encoding + -- on your system, which is also available as 'localeEncoding'. + -- (GHC note: on Windows, we currently do not support double-byte + -- encodings; if the console\'s code page is unsupported, then + -- 'localeEncoding' will be 'latin1'.) + -- + -- Encoding and decoding errors are always detected and reported, + -- except during lazy I/O ('hGetContents', 'getContents', and + -- 'readFile'), where a decoding error merely results in + -- termination of the character stream, as with other I/O errors. + + hSetEncoding, + hGetEncoding, + + -- ** Unicode encodings + TextEncoding, + latin1, + utf8, utf8_bom, + utf16, utf16le, utf16be, + utf32, utf32le, utf32be, + localeEncoding, + char8, + mkTextEncoding, +#endif + +#if !defined(__NHC__) && !defined(__HUGS__) + -- * Newline conversion + + -- | In Haskell, a newline is always represented by the character + -- '\n'. However, in files and external character streams, a + -- newline may be represented by another character sequence, such + -- as '\r\n'. + -- + -- A text-mode 'Handle' has an associated 'NewlineMode' that + -- specifies how to transate newline characters. The + -- 'NewlineMode' specifies the input and output translation + -- separately, so that for instance you can translate '\r\n' + -- to '\n' on input, but leave newlines as '\n' on output. + -- + -- The default 'NewlineMode' for a 'Handle' is + -- 'nativeNewlineMode', which does no translation on Unix systems, + -- but translates '\r\n' to '\n' and back on Windows. + -- + -- Binary-mode 'Handle's do no newline translation at all. + -- + hSetNewlineMode, + Newline(..), nativeNewline, + NewlineMode(..), + noNewlineTranslation, universalNewlineMode, nativeNewlineMode, #endif ) where +import Control.Exception.Base + +#ifndef __NHC__ +import Data.Bits +import Data.List +import Data.Maybe +import Foreign.C.Error +import Foreign.C.Types +import System.Posix.Internals +import System.Posix.Types +#endif + #ifdef __GLASGOW_HASKELL__ import GHC.Base -import GHC.IOBase -- Together these four Prelude modules define -import GHC.Handle -- all the stuff exported by IO for the GHC version -import GHC.IO -import GHC.Exception +import GHC.IO hiding ( bracket, onException ) +import GHC.IO.IOMode +import GHC.IO.Handle.FD +import qualified GHC.IO.FD as FD +import GHC.IO.Handle +import GHC.IO.Handle.Text ( hGetBufSome, hPutStrLn ) +import GHC.IORef +import GHC.IO.Exception ( userError ) +import GHC.IO.Encoding import GHC.Num -import GHC.Read +import Text.Read import GHC.Show #endif @@ -178,9 +264,7 @@ import GHC.Show import Hugs.IO import Hugs.IOExts import Hugs.IORef -import Hugs.Prelude ( throw, Exception(NonTermination) ) -import Control.Exception ( bracket ) -import System.IO.Unsafe ( unsafeInterleaveIO ) +import System.IO.Unsafe ( unsafeInterleaveIO ) #endif #ifdef __NHC__ @@ -243,8 +327,7 @@ putStr s = hPutStr stdout s -- | The same as 'putStr', but adds a newline character. putStrLn :: String -> IO () -putStrLn s = do putStr s - putChar '\n' +putStrLn s = hPutStrLn stdout s -- | The 'print' function outputs a value of any printable type to the -- standard output device. @@ -293,7 +376,7 @@ interact f = do s <- getContents -- The file is read lazily, on demand, as with 'getContents'. readFile :: FilePath -> IO String -readFile name = openFile name ReadMode >>= hGetContents +readFile name = openFile name ReadMode >>= hGetContents -- | The computation 'writeFile' @file str@ function writes the string @str@, -- to the file @file@. @@ -324,11 +407,11 @@ readLn = do l <- getLine readIO :: Read a => String -> IO a readIO s = case (do { (x,t) <- reads s ; - ("","") <- lex t ; + ("","") <- lex t ; return x }) of - [x] -> return x - [] -> ioError (userError "Prelude.readIO: no parse") - _ -> ioError (userError "Prelude.readIO: ambiguous parse") + [x] -> return x + [] -> ioError (userError "Prelude.readIO: no parse") + _ -> ioError (userError "Prelude.readIO: ambiguous parse") #endif /* __GLASGOW_HASKELL__ */ #ifndef __NHC__ @@ -339,15 +422,8 @@ readIO s = case (do { (x,t) <- reads s ; -- -- * 'System.IO.Error.isEOFError' if the end of file has been reached. -hReady :: Handle -> IO Bool -hReady h = hWaitForInput h 0 - --- | The same as 'hPutStr', but adds a newline character. - -hPutStrLn :: Handle -> String -> IO () -hPutStrLn hndl str = do - hPutStr hndl str - hPutChar hndl '\n' +hReady :: Handle -> IO Bool +hReady h = hWaitForInput h 0 -- | Computation 'hPrint' @hdl t@ writes the string representation of @t@ -- given by the 'shows' function to the file or channel managed by @hdl@ @@ -359,14 +435,16 @@ hPutStrLn hndl str = do -- -- * 'System.IO.Error.isPermissionError' if another system resource limit would be exceeded. -hPrint :: Show a => Handle -> a -> IO () -hPrint hdl = hPutStrLn hdl . show +hPrint :: Show a => Handle -> a -> IO () +hPrint hdl = hPutStrLn hdl . show #endif /* !__NHC__ */ -- | @'withFile' name mode act@ opens a file using 'openFile' and passes -- the resulting handle to the computation @act@. The handle will be -- closed on exit from 'withFile', whether by normal termination or by --- raising an exception. +-- raising an exception. If closing the handle raises an exception, then +-- this exception will be raised by 'withFile' rather than any exception +-- raised by 'act'. withFile :: FilePath -> IOMode -> (Handle -> IO r) -> IO r withFile name mode = bracket (openFile name mode) hClose @@ -398,13 +476,150 @@ fixIO k = do -- Assume a unix platform, where text and binary I/O are identical. openBinaryFile = openFile hSetBinaryMode _ _ = return () + +type CMode = Int +#endif + +-- | The function creates a temporary file in ReadWrite mode. +-- The created file isn\'t deleted automatically, so you need to delete it manually. +-- +-- The file is creates with permissions such that only the current +-- user can read\/write it. +-- +-- With some exceptions (see below), the file will be created securely +-- in the sense that an attacker should not be able to cause +-- openTempFile to overwrite another file on the filesystem using your +-- credentials, by putting symbolic links (on Unix) in the place where +-- the temporary file is to be created. On Unix the @O_CREAT@ and +-- @O_EXCL@ flags are used to prevent this attack, but note that +-- @O_EXCL@ is sometimes not supported on NFS filesystems, so if you +-- rely on this behaviour it is best to use local filesystems only. +-- +openTempFile :: FilePath -- ^ Directory in which to create the file + -> String -- ^ File name template. If the template is \"foo.ext\" then + -- the created file will be \"fooXXX.ext\" where XXX is some + -- random number. + -> IO (FilePath, Handle) +openTempFile tmp_dir template + = openTempFile' "openTempFile" tmp_dir template False 0o600 + +-- | 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 0o600 + +-- | Like 'openTempFile', but uses the default file permissions +openTempFileWithDefaultPermissions :: FilePath -> String + -> IO (FilePath, Handle) +openTempFileWithDefaultPermissions tmp_dir template + = openTempFile' "openBinaryTempFile" tmp_dir template False 0o666 + +-- | Like 'openBinaryTempFile', but uses the default file permissions +openBinaryTempFileWithDefaultPermissions :: FilePath -> String + -> IO (FilePath, Handle) +openBinaryTempFileWithDefaultPermissions tmp_dir template + = openTempFile' "openBinaryTempFile" tmp_dir template True 0o666 + +openTempFile' :: String -> FilePath -> String -> Bool -> CMode + -> IO (FilePath, Handle) +openTempFile' loc tmp_dir template binary mode = do + pid <- c_getpid + findTempName pid + where + -- We split off the last extension, so we can use .foo.ext files + -- for temporary files (hidden on Unix OSes). Unfortunately we're + -- below filepath in the hierarchy here. + (prefix,suffix) = + case break (== '.') $ reverse template of + -- First case: template contains no '.'s. Just re-reverse it. + (rev_suffix, "") -> (reverse rev_suffix, "") + -- Second case: template contains at least one '.'. Strip the + -- dot from the prefix and prepend it to the suffix (if we don't + -- do this, the unique number will get added after the '.' and + -- thus be part of the extension, which is wrong.) + (rev_suffix, '.':rest) -> (reverse rest, '.':reverse rev_suffix) + -- Otherwise, something is wrong, because (break (== '.')) should + -- always return a pair with either the empty string or a string + -- beginning with '.' as the second component. + _ -> error "bug in System.IO.openTempFile" + +#ifndef __NHC__ + oflags1 = rw_flags .|. o_EXCL + + binary_flags + | binary = o_BINARY + | otherwise = 0 + + oflags = oflags1 .|. binary_flags +#endif + +#if defined(__NHC__) + findTempName x = do h <- openFile filepath ReadWriteMode + return (filepath, h) +#elif defined(__GLASGOW_HASKELL__) + findTempName x = do + fd <- withFilePath filepath $ \ f -> + c_open f oflags mode + 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 + + (fD,fd_type) <- FD.mkFD fd ReadWriteMode Nothing{-no stat-} + False{-is_socket-} + True{-is_nonblock-} + + h <- mkHandleFromFD fD fd_type filepath ReadWriteMode False{-set non-block-} + (Just localeEncoding) + + return (filepath, h) +#else + h <- fdToHandle fd `onException` c_close fd + return (filepath, h) +#endif + + where + filename = prefix ++ show x ++ suffix + filepath = tmp_dir `combine` filename + + -- XXX bits copied from System.FilePath, since that's not available here + combine a b + | null b = a + | null a = b + | last a == pathSeparator = a ++ b + | otherwise = a ++ [pathSeparator] ++ b + +#if __HUGS__ + fdToHandle fd = openFd (fromIntegral fd) False ReadWriteMode binary +#endif + +-- XXX Should use filepath library +pathSeparator :: Char +#ifdef mingw32_HOST_OS +pathSeparator = '\\' +#else +pathSeparator = '/' +#endif + +#ifndef __NHC__ +-- XXX Copied from GHC.Handle +std_flags, output_flags, rw_flags :: CInt +std_flags = o_NONBLOCK .|. o_NOCTTY +output_flags = std_flags .|. o_CREAT +rw_flags = output_flags .|. o_RDWR +#endif + +#ifdef __NHC__ +foreign import ccall "getpid" c_getpid :: IO Int #endif -- $locking -- Implementations should enforce as far as possible, at least locally to the -- Haskell process, multiple-reader single-writer locking on files. --- That is, /there may either be many handles on the same file which manage --- input, or just one handle on the file which manages output/. If any +-- That is, /there may either be many handles on the same file which manage input, or just one handle on the file which manages output/. If any -- open or semi-closed handle is managing a file for output, no new -- handle can be allocated for that file. If any open or semi-closed -- handle is managing a file for input, new handles can only be allocated @@ -418,24 +633,3 @@ hSetBinaryMode _ _ = return () -- It follows that an attempt to write to a file (using 'writeFile', for -- example) that was earlier opened by 'readFile' will usually result in -- failure with 'System.IO.Error.isAlreadyInUseError'. - --- ----------------------------------------------------------------------------- --- Utils - -#ifdef __GLASGOW_HASKELL__ --- Copied here to avoid recursive dependency with Control.Exception -bracket - :: IO a -- ^ computation to run first (\"acquire resource\") - -> (a -> IO b) -- ^ computation to run last (\"release resource\") - -> (a -> IO c) -- ^ computation to run in-between - -> IO c -- returns the value from the in-between computation -bracket before after thing = - block (do - a <- before - r <- catchException - (unblock (thing a)) - (\e -> do { after a; throw e }) - after a - return r - ) -#endif