73 lines
1.9 KiB
Haskell
73 lines
1.9 KiB
Haskell
{- More control over touching a file.
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-
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- Copyright 2011 Joey Hess <joey@kitenet.net>
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-
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- Licensed under the GNU GPL version 3 or higher.
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-}
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{-# LANGUAGE ForeignFunctionInterface #-}
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module Touch (
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TimeSpec(..),
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nowTime,
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omitTime,
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touchBoth,
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touch
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) where
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import Foreign
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import Foreign.C
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#include <sys/types.h>
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#include <sys/stat.h>
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#include <fcntl.h>
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data TimeSpec = TimeSpec CTime CLong
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instance Storable TimeSpec where
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-- use the larger alignment of the two types in the struct
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alignment _ = max sec_alignment nsec_alignment
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where
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sec_alignment = alignment (undefined::CTime)
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nsec_alignment = alignment (undefined::CLong)
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sizeOf _ = #{size struct timespec}
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peek ptr = do
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sec <- #{peek struct timespec, tv_sec} ptr
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nsec <- #{peek struct timespec, tv_nsec} ptr
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return $ TimeSpec sec nsec
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poke ptr (TimeSpec sec nsec) = do
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#{poke struct timespec, tv_sec} ptr sec
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#{poke struct timespec, tv_nsec} ptr nsec
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{- special timespecs -}
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omitTime :: TimeSpec
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omitTime = TimeSpec 0 #const UTIME_OMIT
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nowTime :: TimeSpec
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nowTime = TimeSpec 0 #const UTIME_NOW
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{- While its interface is beastly, utimensat is in recent
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POSIX standards, unlike futimes. -}
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foreign import ccall "utimensat"
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c_utimensat :: CInt -> CString -> Ptr TimeSpec -> CInt -> IO CInt
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{- Changes the access and/or modification times of an existing file.
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Can follow symlinks, or not. Throws IO error on failure. -}
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touchBoth :: FilePath -> TimeSpec -> TimeSpec -> Bool -> IO ()
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touchBoth file atime mtime follow =
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allocaArray 2 $ \ptr ->
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withCString file $ \f -> do
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pokeArray ptr [atime, mtime]
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r <- c_utimensat at_fdcwd f ptr flags
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if (r /= 0)
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then throwErrno "touchBoth"
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else return ()
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where
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at_fdcwd = #const AT_FDCWD
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at_symlink_nofollow = #const AT_SYMLINK_NOFOLLOW
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flags = if follow
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then 0
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else at_symlink_nofollow
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touch :: FilePath -> TimeSpec -> Bool -> IO ()
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touch file mtime follow = touchBoth file omitTime mtime follow
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