Supports indirect mode on encfs in paranoia mode, and other filesystems that do not support hard links, but do support symlinks and other POSIX filesystem features.

Utility/CopyFile.hs

@@ -1,11 +1,16 @@
-{- git-annex file copying
+{- file copying
  -
- - Copyright 2010,2012 Joey Hess <joey@kitenet.net>
+ - Copyright 2010-2013 Joey Hess <joey@kitenet.net>
  -
  - Licensed under the GNU GPL version 3 or higher.
  -}
 
-module Utility.CopyFile (copyFileExternal) where
+{-# LANGUAGE CPP #-}
+
+module Utility.CopyFile (
+	copyFileExternal,
+	createLinkOrCopy
+) where
 
 import Common
 import qualified Build.SysConfig as SysConfig
@@ -23,3 +28,17 @@ copyFileExternal src dest = do
 		, (SysConfig.cp_a, Param "-a")
 		, (SysConfig.cp_p && not SysConfig.cp_a, Param "-p")
 		]
+
+{- 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