wip RawFilePath 2x git-annex find speedup

Finally builds (oh the agoncy of making it build), but still very
unmergable, only Command.Find is included and lots of stuff is badly
hacked to make it compile.

Benchmarking vs master, this git-annex find is significantly faster!
Specifically:

	num files	old	new	speedup
	48500		4.77	3.73	28%
	12500		1.36	1.02	66%
	20		0.075	0.074	0% (so startup time is unchanged)

That's without really finishing the optimization. Things still to do:

* Eliminate all the fromRawFilePath, toRawFilePath, encodeBS,
  decodeBS conversions.
* Use versions of IO actions like getFileStatus that take a RawFilePath.
* Eliminate some Data.ByteString.Lazy.toStrict, which is a slow copy.
* Use ByteString for parsing git config to speed up startup.

It's likely several of those will speed up git-annex find further.
And other commands will certianly benefit even more.

Database/Export.hs

@@ -128,28 +128,28 @@ addExportedLocation :: ExportHandle -> Key -> ExportLocation -> IO ()
 addExportedLocation h k el = queueDb h $ do
 	void $ insertUnique $ Exported ik ef
 	let edirs = map
-		(\ed -> ExportedDirectory (toSFilePath (fromExportDirectory ed)) ef)
+		(\ed -> ExportedDirectory (toSFilePath (fromRawFilePath (fromExportDirectory ed))) ef)
 		(exportDirectories el)
 	putMany edirs
   where
 	ik = toIKey k
-	ef = toSFilePath (fromExportLocation el)
+	ef = toSFilePath $ fromRawFilePath $ fromExportLocation el
 
 removeExportedLocation :: ExportHandle -> Key -> ExportLocation -> IO ()
 removeExportedLocation h k el = queueDb h $ do
 	deleteWhere [ExportedKey ==. ik, ExportedFile ==. ef]
-	let subdirs = map (toSFilePath . fromExportDirectory)
+	let subdirs = map (toSFilePath . fromRawFilePath . fromExportDirectory)
 		(exportDirectories el)
 	deleteWhere [ExportedDirectoryFile ==. ef, ExportedDirectorySubdir <-. subdirs]
   where
 	ik = toIKey k
-	ef = toSFilePath (fromExportLocation el)
+	ef = toSFilePath $ fromRawFilePath $ fromExportLocation el
 
 {- Note that this does not see recently queued changes. -}
 getExportedLocation :: ExportHandle -> Key -> IO [ExportLocation]
 getExportedLocation (ExportHandle h _) k = H.queryDbQueue h $ do
 	l <- selectList [ExportedKey ==. ik] []
-	return $ map (mkExportLocation . fromSFilePath . exportedFile . entityVal) l
+	return $ map (mkExportLocation . toRawFilePath . fromSFilePath . exportedFile . entityVal) l
   where
 	ik = toIKey k
 
@@ -159,13 +159,13 @@ isExportDirectoryEmpty (ExportHandle h _) d = H.queryDbQueue h $ do
 	l <- selectList [ExportedDirectorySubdir ==. ed] []
 	return $ null l
   where
-	ed = toSFilePath $ fromExportDirectory d
+	ed = toSFilePath $ fromRawFilePath $ fromExportDirectory d
 
 {- Get locations in the export that might contain a key. -}
 getExportTree :: ExportHandle -> Key -> IO [ExportLocation]
 getExportTree (ExportHandle h _) k = H.queryDbQueue h $ do
 	l <- selectList [ExportTreeKey ==. ik] []
-	return $ map (mkExportLocation . fromSFilePath . exportTreeFile . entityVal) l
+	return $ map (mkExportLocation . toRawFilePath . fromSFilePath . exportTreeFile . entityVal) l
   where
 	ik = toIKey k
 
@@ -181,21 +181,21 @@ getExportTreeKey (ExportHandle h _) el = H.queryDbQueue h $ do
 	map (fromIKey . exportTreeKey . entityVal) 
 		<$> selectList [ExportTreeFile ==. ef] []
   where
-	ef = toSFilePath (fromExportLocation el)
+	ef = toSFilePath (fromRawFilePath $ fromExportLocation el)
 
 addExportTree :: ExportHandle -> Key -> ExportLocation -> IO ()
 addExportTree h k loc = queueDb h $
 	void $ insertUnique $ ExportTree ik ef
   where
 	ik = toIKey k
-	ef = toSFilePath (fromExportLocation loc)
+	ef = toSFilePath (fromRawFilePath $ fromExportLocation loc)
 
 removeExportTree :: ExportHandle -> Key -> ExportLocation -> IO ()
 removeExportTree h k loc = queueDb h $
 	deleteWhere [ExportTreeKey ==. ik, ExportTreeFile ==. ef]
   where
 	ik = toIKey k
-	ef = toSFilePath (fromExportLocation loc)
+	ef = toSFilePath (fromRawFilePath $ fromExportLocation loc)
 
 -- An action that is passed the old and new values that were exported,
 -- and updates state.
@@ -220,7 +220,7 @@ mkExportDiffUpdater removeold addnew h srcek dstek i = do
 		Nothing -> return ()
 		Just k -> liftIO $ addnew h (asKey k) loc
   where
-	loc = mkExportLocation $ getTopFilePath $ Git.DiffTree.file i
+	loc = mkExportLocation $ toRawFilePath $ getTopFilePath $ Git.DiffTree.file i
 
 runExportDiffUpdater :: ExportDiffUpdater -> ExportHandle -> Sha -> Sha -> Annex ()
 runExportDiffUpdater updater h old new = do