better directory handling

Rename Locations functions for better consitency, and make their values
more consistent too.

Used </> rather than manually building paths. There are still more places
that manually do so, but are tricky, due to the behavior of </> when
the second FilePath is absolute. So I only changed places where
it obviously was relative.

Locations.hs

@@ -7,73 +7,93 @@
 
 module Locations (
 	gitStateDir,
-	stateLoc,
+	stateDir,
 	keyFile,
 	fileKey,
+	gitAnnexLocation,
 	annexLocation,
-	annexLocationRelative,
-	annexTmpLocation,
-	annexBadLocation,
-	annexUnusedLog,
+	gitAnnexDir,
+	gitAnnexObjectDir,
+	gitAnnexTmpDir,
+	gitAnnexBadDir,
+	gitAnnexUnusedLog,
 	isLinkToAnnex,
-	annexDir,
-	annexObjectDir,
 
 	prop_idempotent_fileKey
 ) where
 
+import System.FilePath
 import Data.String.Utils
 import Data.List
 
 import Types
 import qualified GitRepo as Git
 
+{- Conventions:
+ -
+ - Functions ending in "Dir" should always return values ending with a
+ - trailing path separator. Most code does not rely on that, but a few
+ - things do. 
+ -
+ - Everything else should not end in a trailing path sepatator. 
+ -
+ - Only functions (with names starting with "git") that build a path
+ - based on a git repository should return an absolute path.
+ - Everything else should use relative paths.
+ -}
+
 {- Long-term, cross-repo state is stored in files inside the .git-annex
  - directory, in the git repository's working tree. -}
-stateLoc :: String
-stateLoc = ".git-annex/"
+stateDir :: FilePath
+stateDir = addTrailingPathSeparator $ ".git-annex"
 gitStateDir :: Git.Repo -> FilePath
-gitStateDir repo = Git.workTree repo ++ "/" ++ stateLoc
+gitStateDir repo = addTrailingPathSeparator $ Git.workTree repo </> stateDir
 
-{- Annexed file's absolute location. -}
-annexLocation :: Git.Repo -> Key -> FilePath
-annexLocation r key = 
-	Git.workTree r ++ "/" ++ annexLocationRelative key
+{- Annexed content is stored in .git/annex/objects; .git/annex is used
+ - for other temporary storage also. -}
+annexDir :: FilePath
+annexDir = addTrailingPathSeparator $ ".git/annex"
+objectDir :: FilePath
+objectDir = addTrailingPathSeparator $ annexDir </> "objects"
 
 {- Annexed file's location relative to git's working tree. 
  -
  - Note: Assumes repo is NOT bare.-}
-annexLocationRelative :: Key -> FilePath
-annexLocationRelative key = ".git/annex/objects/" ++ f ++ "/" ++ f
+annexLocation :: Key -> FilePath
+annexLocation key = ".git/annex/objects" </> f </> f
 	where
 		f = keyFile key
 
+{- Annexed file's absolute location in a repository. -}
+gitAnnexLocation :: Git.Repo -> Key -> FilePath
+gitAnnexLocation r key = Git.workTree r </> annexLocation key
+
 {- The annex directory of a repository.
  -
  - Note: Assumes repo is NOT bare. -}
-annexDir :: Git.Repo -> FilePath
-annexDir r = Git.workTree r ++ "/.git/annex"
+gitAnnexDir :: Git.Repo -> FilePath
+gitAnnexDir r = addTrailingPathSeparator $ Git.workTree r </> annexDir
 
 {- The part of the annex directory where file contents are stored.
  -}
-annexObjectDir :: Git.Repo -> FilePath
-annexObjectDir r = annexDir r ++ "/objects"
+gitAnnexObjectDir :: Git.Repo -> FilePath
+gitAnnexObjectDir r = addTrailingPathSeparator $ Git.workTree r </> objectDir
 
 {- .git-annex/tmp/ is used for temp files -}
-annexTmpLocation :: Git.Repo -> FilePath
-annexTmpLocation r = annexDir r ++ "/tmp/"
+gitAnnexTmpDir :: Git.Repo -> FilePath
+gitAnnexTmpDir r = addTrailingPathSeparator $ gitAnnexDir r </> "tmp"
 
 {- .git-annex/bad/ is used for bad files found during fsck -}
-annexBadLocation :: Git.Repo -> FilePath
-annexBadLocation r = annexDir r ++ "/bad/"
+gitAnnexBadDir :: Git.Repo -> FilePath
+gitAnnexBadDir r = addTrailingPathSeparator $ gitAnnexDir r </> "bad"
 
 {- .git/annex/unused is used to number possibly unused keys -}
-annexUnusedLog :: Git.Repo -> FilePath
-annexUnusedLog r = annexDir r ++ "/unused"
+gitAnnexUnusedLog :: Git.Repo -> FilePath
+gitAnnexUnusedLog r = gitAnnexDir r </> "unused"
 
 {- Checks a symlink target to see if it appears to point to annexed content. -}
 isLinkToAnnex :: FilePath -> Bool
-isLinkToAnnex s = isInfixOf "/.git/annex/objects/" s
+isLinkToAnnex s = isInfixOf ("/" ++ objectDir) s
 
 {- Converts a key into a filename fragment.
  -