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|
{- file copying
-
- Copyright 2010-2014 Joey Hess <id@joeyh.name>
-
- License: BSD-2-clause
-}
module Utility.CopyFile (
copyFileExternal,
createLinkOrCopy,
CopyMetaData(..)
) where
import Common
import qualified BuildInfo
data CopyMetaData
-- Copy timestamps when possible, but no other metadata, and
-- when copying a symlink, makes a copy of its content.
= CopyTimeStamps
-- Copy all metadata when possible.
| CopyAllMetaData
deriving (Eq)
{- The cp command is used, because I hate reinventing the wheel,
- and because this allows easy access to features like cp --reflink. -}
copyFileExternal :: CopyMetaData -> FilePath -> FilePath -> IO Bool
copyFileExternal meta src dest = do
whenM (doesFileExist dest) $
removeFile dest
boolSystem "cp" $ params ++ [File src, File dest]
where
params = map snd $ filter fst
[ (BuildInfo.cp_reflink_auto, Param "--reflink=auto")
, (allmeta && BuildInfo.cp_a, Param "-a")
, (allmeta && BuildInfo.cp_p && not BuildInfo.cp_a
, Param "-p")
, (not allmeta && BuildInfo.cp_preserve_timestamps
, Param "--preserve=timestamps")
]
allmeta = meta == CopyAllMetaData
{- Create a hard link if the filesystem allows it, and fall back to copying
- the file. -}
createLinkOrCopy :: FilePath -> FilePath -> IO Bool
createLinkOrCopy src dest = go `catchIO` const fallback
where
go = do
createLink src dest
return True
fallback = copyFileExternal CopyAllMetaData src dest
|
