git-annex/Utility/CopyFile.hs

48 lines
1.2 KiB
Haskell

{- file copying
-
- Copyright 2010-2013 Joey Hess <joey@kitenet.net>
-
- Licensed under the GNU GPL version 3 or higher.
-}
{-# LANGUAGE CPP #-}
module Utility.CopyFile (
copyFileExternal,
createLinkOrCopy
) where
import Common
import qualified Build.SysConfig as SysConfig
{- The cp command is used, because I hate reinventing the wheel,
- and because this allows easy access to features like cp --reflink. -}
copyFileExternal :: FilePath -> FilePath -> IO Bool
copyFileExternal src dest = do
whenM (doesFileExist dest) $
removeFile dest
boolSystem "cp" $ params ++ [File src, File dest]
where
#ifndef __ANDROID__
params = map snd $ filter fst
[ (SysConfig.cp_reflink_auto, Param "--reflink=auto")
, (SysConfig.cp_a, Param "-a")
, (SysConfig.cp_p && not SysConfig.cp_a, Param "-p")
]
#else
params = []
#endif
{- Create a hard link if the filesystem allows it, and fall back to copying
- the file. -}
createLinkOrCopy :: FilePath -> FilePath -> IO Bool
#ifndef __WINDOWS__
createLinkOrCopy src dest = go `catchIO` const fallback
where
go = do
createLink src dest
return True
fallback = copyFileExternal src dest
#else
createLinkOrCopy = copyFileExternal
#endif