1. 12 Jun, 2009 1 commit
    • Simon Marlow's avatar
      Rewrite of the IO library, including Unicode support · 7b067f2d
      Simon Marlow authored
      Highlights:
      
      * Unicode support for Handle I/O:
      
        ** Automatic encoding and decoding using a per-Handle encoding.
      
        ** The encoding defaults to the locale encoding (only on Unix 
           so far, perhaps Windows later).
      
        ** Built-in UTF-8, UTF-16 (BE/LE), and UTF-32 (BE/LE) codecs.
      
        ** iconv-based codec for other encodings on Unix
      
      * Modularity: the low-level IO interface is exposed as a type class
        (GHC.IO.IODevice) so you can build your own low-level IO providers and
        make Handles from them.
      
      * Newline translation: instead of being Windows-specific wired-in
        magic, the translation from \r\n -> \n and back again is available
        on all platforms and is configurable for reading/writing
        independently.
      
      
      Unicode-aware Handles
      ~~~~~~~~~~~~~~~~~~~~~
      
      This is a significant restructuring of the Handle implementation with
      the primary goal of supporting Unicode character encodings.
      
      The only change to the existing behaviour is that by default, text IO
      is done in the prevailing locale encoding of the system (except on
      Windows [1]).  
      
      Handles created by openBinaryFile use the Latin-1 encoding, as do
      Handles placed in binary mode using hSetBinaryMode.
      
      We provide a way to change the encoding for an existing Handle:
      
         GHC.IO.Handle.hSetEncoding :: Handle -> TextEncoding -> IO ()
      
      and various encodings (from GHC.IO.Encoding):
      
         latin1,
         utf8,
         utf16, utf16le, utf16be,
         utf32, utf32le, utf32be,
         localeEncoding,
      
      and a way to lookup other encodings:
      
         GHC.IO.Encoding.mkTextEncoding :: String -> IO TextEncoding
      
      (it's system-dependent whether the requested encoding will be
      available).
      
      We may want to export these from somewhere more permanent; that's a
      topic for a future library proposal.
      
      Thanks to suggestions from Duncan Coutts, it's possible to call
      hSetEncoding even on buffered read Handles, and the right thing
      happens.  So we can read from text streams that include multiple
      encodings, such as an HTTP response or email message, without having
      to turn buffering off (though there is a penalty for switching
      encodings on a buffered Handle, as the IO system has to do some
      re-decoding to figure out where it should start reading from again).
      
      If there is a decoding error, it is reported when an attempt is made
      to read the offending character from the Handle, as you would expect.
      
      Performance varies.  For "hGetContents >>= putStr" I found the new
      library was faster on my x86_64 machine, but slower on an x86.  On the
      whole I'd expect things to be a bit slower due to the extra
      decoding/encoding, but probabaly not noticeably.  If performance is
      critical for your app, then you should be using bytestring and text
      anyway.
      
      [1] Note: locale encoding is not currently implemented on Windows due
      to the built-in Win32 APIs for encoding/decoding not being sufficient
      for our purposes.  Ask me for details.  Offers of help gratefully
      accepted.
      
      
      Newline Translation
      ~~~~~~~~~~~~~~~~~~~
      
      In the old IO library, text-mode Handles on Windows had automatic
      translation from \r\n -> \n on input, and the opposite on output.  It
      was implemented using the underlying CRT functions, which meant that
      there were certain odd restrictions, such as read/write text handles
      needing to be unbuffered, and seeking not working at all on text
      Handles.
      
      In the rewrite, newline translation is now implemented in the upper
      layers, as it needs to be since we have to perform Unicode decoding
      before newline translation.  This means that it is now available on
      all platforms, which can be quite handy for writing portable code.
      
      For now, I have left the behaviour as it was, namely \r\n -> \n on
      Windows, and no translation on Unix.  However, another reasonable
      default (similar to what Python does) would be to do \r\n -> \n on
      input, and convert to the platform-native representation (either \r\n
      or \n) on output.  This is called universalNewlineMode (below).
      
      The API is as follows.  (available from GHC.IO.Handle for now, again
      this is something we will probably want to try to get into System.IO
      at some point):
      
      -- | The representation of a newline in the external file or stream.
      data Newline = LF    -- ^ "\n"
                   | CRLF  -- ^ "\r\n"
                   deriving Eq
      
      -- | Specifies the translation, if any, of newline characters between
      -- internal Strings and the external file or stream.  Haskell Strings
      -- are assumed to represent newlines with the '\n' character; the
      -- newline mode specifies how to translate '\n' on output, and what to
      -- translate into '\n' on input.
      data NewlineMode 
        = NewlineMode { inputNL :: Newline,
                          -- ^ the representation of newlines on input
                        outputNL :: Newline
                          -- ^ the representation of newlines on output
                       }
                   deriving Eq
      
      -- | The native newline representation for the current platform
      nativeNewline :: Newline
      
      -- | Map "\r\n" into "\n" on input, and "\n" to the native newline
      -- represetnation on output.  This mode can be used on any platform, and
      -- works with text files using any newline convention.  The downside is
      -- that @readFile a >>= writeFile b@ might yield a different file.
      universalNewlineMode :: NewlineMode
      universalNewlineMode  = NewlineMode { inputNL  = CRLF, 
                                            outputNL = nativeNewline }
      
      -- | Use the native newline representation on both input and output
      nativeNewlineMode    :: NewlineMode
      nativeNewlineMode     = NewlineMode { inputNL  = nativeNewline, 
                                            outputNL = nativeNewline }
      
      -- | Do no newline translation at all.
      noNewlineTranslation :: NewlineMode
      noNewlineTranslation  = NewlineMode { inputNL  = LF, outputNL = LF }
      
      
      -- | Change the newline translation mode on the Handle.
      hSetNewlineMode :: Handle -> NewlineMode -> IO ()
      
      
      
      IO Devices
      ~~~~~~~~~~
      
      The major change here is that the implementation of the Handle
      operations is separated from the underlying IO device, using type
      classes.  File descriptors are just one IO provider; I have also
      implemented memory-mapped files (good for random-access read/write)
      and a Handle that pipes output to a Chan (useful for testing code that
      writes to a Handle).  New kinds of Handle can be implemented outside
      the base package, for instance someone could write bytestringToHandle.
      A Handle is made using mkFileHandle:
      
      -- | makes a new 'Handle'
      mkFileHandle :: (IODevice dev, BufferedIO dev, Typeable dev)
                    => dev -- ^ the underlying IO device, which must support
                           -- 'IODevice', 'BufferedIO' and 'Typeable'
                    -> FilePath
                           -- ^ a string describing the 'Handle', e.g. the file
                           -- path for a file.  Used in error messages.
                    -> IOMode
                           -- ^ The mode in which the 'Handle' is to be used
                    -> Maybe TextEncoding
                           -- ^ text encoding to use, if any
                    -> NewlineMode
                           -- ^ newline translation mode
                    -> IO Handle
      
      This also means that someone can write a completely new IO
      implementation on Windows based on native Win32 HANDLEs, and
      distribute it as a separate package (I really hope somebody does
      this!).
      
      This restructuring isn't as radical as previous designs.  I haven't
      made any attempt to make a separate binary I/O layer, for example
      (although hGetBuf/hPutBuf do bypass the text encoding and newline
      translation).  The main goal here was to get Unicode support in, and
      to allow others to experiment with making new kinds of Handle.  We
      could split up the layers further later.
      
      
      API changes and Module structure
      ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
      
      NB. GHC.IOBase and GHC.Handle are now DEPRECATED (they are still
      present, but are just re-exporting things from other modules now).
      For 6.12 we'll want to bump base to version 5 and add a base4-compat.
      For now I'm using #if __GLASGOW_HASKEL__ >= 611 to avoid deprecated
      warnings.
      
      I split modules into smaller parts in many places.  For example, we
      now have GHC.IORef, GHC.MVar and GHC.IOArray containing the
      implementations of IORef, MVar and IOArray respectively.  This was
      necessary for untangling dependencies, but it also makes things easier
      to follow.
      
      The new module structurue for the IO-relatied parts of the base
      package is:
      
      GHC.IO
         Implementation of the IO monad; unsafe*; throw/catch
      
      GHC.IO.IOMode
         The IOMode type
      
      GHC.IO.Buffer
         Buffers and operations on them
      
      GHC.IO.Device
         The IODevice and RawIO classes.
      
      GHC.IO.BufferedIO
         The BufferedIO class.
      
      GHC.IO.FD
         The FD type, with instances of IODevice, RawIO and BufferedIO.
      
      GHC.IO.Exception
         IO-related Exceptions
      
      GHC.IO.Encoding
         The TextEncoding type; built-in TextEncodings; mkTextEncoding
      
      GHC.IO.Encoding.Types
      GHC.IO.Encoding.Iconv
      GHC.IO.Encoding.Latin1
      GHC.IO.Encoding.UTF8
      GHC.IO.Encoding.UTF16
      GHC.IO.Encoding.UTF32
         Implementation internals for GHC.IO.Encoding
      
      GHC.IO.Handle
         The main API for GHC's Handle implementation, provides all the Handle
         operations + mkFileHandle + hSetEncoding.
      
      GHC.IO.Handle.Types
      GHC.IO.Handle.Internals
      GHC.IO.Handle.Text
         Implementation of Handles and operations.
      
      GHC.IO.Handle.FD
         Parts of the Handle API implemented by file-descriptors: openFile,
         stdin, stdout, stderr, fdToHandle etc.
      7b067f2d
  2. 11 Jun, 2009 1 commit
  3. 05 Jun, 2009 1 commit
  4. 02 Jun, 2009 1 commit
  5. 29 May, 2009 2 commits
    • Simon Marlow's avatar
      Fix validate (on Windows) · d7940ee0
      Simon Marlow authored
      d7940ee0
    • simonpj@microsoft.com's avatar
      Make two type defaults explicit · ac45944d
      simonpj@microsoft.com authored
      Now that -Werror rejects programs that use silent type-class defaulting,
      we must commit in the source code.
      
      I've used Double in CPUTime, which is the same as was picked automatically
      before, but I expect Float would be ok.
      
         realToInteger :: Real a => a -> Integer
         realToInteger ct = round (realToFrac ct :: Double)
      
      In GHC.Float I used Float (rather that than the auto-picked Double)
      because I'm pretty certain it has enough precision.
      
      	-- f :: Integer, log :: Float -> Float, 
              --               ceiling :: Float -> Int
              ceiling ((log (fromInteger (f+1) :: Float) +
       
      ac45944d
  6. 28 May, 2009 1 commit
  7. 24 May, 2009 1 commit
  8. 23 May, 2009 2 commits
  9. 20 May, 2009 3 commits
  10. 24 Apr, 2009 2 commits
  11. 23 Apr, 2009 1 commit
  12. 10 Apr, 2009 1 commit
  13. 03 Apr, 2009 3 commits
  14. 01 Apr, 2009 1 commit
  15. 30 Mar, 2009 1 commit
  16. 27 Mar, 2009 1 commit
  17. 24 Mar, 2009 1 commit
  18. 22 Mar, 2009 1 commit
  19. 16 Mar, 2009 2 commits
  20. 05 Mar, 2009 1 commit
  21. 11 Mar, 2009 1 commit
  22. 05 Mar, 2009 1 commit
    • Simon Marlow's avatar
      Partial fix for #2917 · 7fc5bad1
      Simon Marlow authored
       - add newAlignedPinnedByteArray# for allocating pinned BAs with
         arbitrary alignment
      
       - the old newPinnedByteArray# now aligns to 16 bytes
      
      Foreign.alloca will use newAlignedPinnedByteArray#, and so might end
      up wasting less space than before (we used to align to 8 by default).
      Foreign.allocaBytes and Foreign.mallocForeignPtrBytes will get 16-byte
      aligned memory, which is enough to avoid problems with SSE
      instructions on x86, for example.
      
      There was a bug in the old newPinnedByteArray#: it aligned to 8 bytes,
      but would have failed if the header was not a multiple of 8
      (fortunately it always was, even with profiling).  Also we
      occasionally wasted some space unnecessarily due to alignment in
      allocatePinned().
      
      I haven't done anything about Foreign.malloc/mallocBytes, which will
      give you the same alignment guarantees as malloc() (8 bytes on
      Linux/x86 here).
      7fc5bad1
  23. 07 Mar, 2009 1 commit
  24. 05 Mar, 2009 2 commits
  25. 07 Feb, 2009 1 commit
  26. 12 Feb, 2009 1 commit
  27. 20 Feb, 2009 3 commits
  28. 19 Feb, 2009 2 commits
    • Simon Marlow's avatar
      Set the IO manager pipe descriptors to FD_CLOEXEC · 3c642ac7
      Simon Marlow authored
      This pipe is an internal implementation detail, we don't really want
      it to be exposed.
      3c642ac7
    • Simon Marlow's avatar
      Rewrite of signal-handling (base patch; see also ghc and unix patches) · 1d266a94
      Simon Marlow authored
      The API is the same (for now).  The new implementation has the
      capability to define signal handlers that have access to the siginfo
      of the signal (#592), but this functionality is not exposed in this
      patch.
      
      #2451 is the ticket for the new API.
      
      The main purpose of bringing this in now is to fix race conditions in
      the old signal handling code (#2858).  Later we can enable the new
      API in the HEAD.
      
      Implementation differences:
      
       - More of the signal-handling is moved into Haskell.  We store the
         table of signal handlers in an MVar, rather than having a table of
         StablePtrs in the RTS.
      
       - In the threaded RTS, the siginfo of the signal is passed down the
         pipe to the IO manager thread, which manages the business of
         starting up new signal handler threads.  In the non-threaded RTS,
         the siginfo of caught signals is stored in the RTS, and the
         scheduler starts new signal handler threads.
      1d266a94