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Simon Marlow authored
I/O library rewrite ------------------- This commit replaces the old C/Haskell I/O implementation with a new Haskell-only one using the new FFI & hsc2hs. main points: - lots of code deleted: we're about 3000 lines of C lighter, but the amount of Haskell code is about the same. - performance is ok: some operations are faster, others are slower. There's still some tuning to do, though. - the new library is designed to handle read/write streams much better: a read/write stream gets a special kind of handle internally called a "DuplexHandle", which actually contains two separate handles, one for writing and one for reading. The upshot is that you can do simultaneous reading and writing to/from a socket or FIFO without any locking problems. The effect is similar to calling socketToHandle twice, except that finalization works properly (creating two separate Handles could lead to the socket being closed too early when one of the Handles is GC'd). - hConnectTo and withHandleFor are gone (no one responded to my mail on GHC users, but we can always bring 'em back if necessary). - I made a half-hearted attempt at keeping the system-specific code in one place: see PrelPosix.hsc. - I've rearranged the I/O tests and added lots more. ghc/tests/lib/IO now contains Haskell 98-only IO tests, ghc/test/lib/{IOExts, Directory, Time} now contain tests for the relevant libraries. I haven't quite finished in here yet, the IO tests work but the others don't yet. - I haven't done anything about Unicode yet, but now we can start to discuss what needs doing here. The new library is using MutableByteArrays for its buffers because that turned out to be a *lot* easier (and quicker) than malloc'd buffers - I hope this won't cause trouble for unicode translations though. WARNING: Windows users refrain from updating until we've had a chance to fix any issues that arise. Testing: the basic H98 stuff has been pretty thoroughly tested, but the new duplex handle stuff is still a little green.
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