avoid unncessary db queries when exported directory can't be empty

In rename foo/bar to foo/baz, foo can't be empty.

In delete zxyyz, there's no exported directory (top doesn't count).

Command/Export.hs

@@ -321,4 +321,6 @@ cleanupRename ea db ek src dest = do
 		removeExportLocation db (asKey ek) src
 		addExportLocation db (asKey ek) dest
 		flushDbQueue db
-	removeEmptyDirectories ea db src [asKey ek]
+	if exportedDirectories src /= exportedDirectories dest
+		then removeEmptyDirectories ea db src [asKey ek]
+		else return True

Remote/Helper/Export.hs

@@ -151,18 +151,20 @@ adjustExportable r = case M.lookup "exporttree" (config r) of
 -- exported file, and after calling removeExportLocation and flushing the
 -- database.
 removeEmptyDirectories :: ExportActions Annex -> ExportHandle -> ExportLocation -> [Key] -> Annex Bool
-removeEmptyDirectories ea db loc ks = case removeExportDirectory ea of
-	Nothing -> return True
-	Just removeexportdirectory -> do
-		ok <- allM (go removeexportdirectory) 
-			(reverse (exportedDirectories loc))
-		unless ok $ liftIO $ do
-			-- Add back to export database, so this is
-			-- tried again next time.
-			forM_ ks $ \k ->
-				addExportLocation db k loc
-			flushDbQueue db
-		return ok
+removeEmptyDirectories ea db loc ks
+	| null (exportedDirectories loc) = return True
+	| otherwise = case removeExportDirectory ea of
+		Nothing -> return True
+		Just removeexportdirectory -> do
+			ok <- allM (go removeexportdirectory) 
+				(reverse (exportedDirectories loc))
+			unless ok $ liftIO $ do
+				-- Add back to export database, so this is
+				-- tried again next time.
+				forM_ ks $ \k ->
+					addExportLocation db k loc
+				flushDbQueue db
+			return ok
   where
 	go removeexportdirectory d = 
 		ifM (liftIO $ isExportDirectoryEmpty db d)

Types/Remote.hs

@@ -27,8 +27,8 @@ module Types.Remote
 	where
 
 import qualified Data.Map as M
-import Data.Ord
 import qualified System.FilePath.Posix as Posix
+import Data.Ord
 
 import qualified Git
 import Types.Key
@@ -201,13 +201,14 @@ data ExportActions a = ExportActions
 	, renameExport :: Key -> ExportLocation -> ExportLocation -> a Bool
 	}
 
--- | All directories down to the ExportLocation, with the deepest ones
--- last.
+-- | All subdirectories down to the ExportLocation, with the deepest ones
+-- last. Does not include the top of the export.
 exportedDirectories :: ExportLocation -> [ExportDirectory]
 exportedDirectories (ExportLocation f) =
-	map (ExportDirectory . Posix.joinPath . reverse) $ 
-		subs [] $ map Posix.dropTrailingPathSeparator $
-			Posix.splitPath $ Posix.takeDirectory f
+	map (ExportDirectory . Posix.joinPath . reverse) (subs [] dirs)
   where
 	subs _ [] = []
 	subs ps (d:ds) = (d:ps) : subs (d:ps) ds
+
+	dirs = map Posix.dropTrailingPathSeparator $
+		reverse $ drop 1 $ reverse $ Posix.splitPath f