fix transfers of key with no associated file

Several places assumed this would not happen, and when the AssociatedFile
was Nothing, did nothing.

As part of this, preferred content checks pass the Key around.

Note that checkMatcher is sometimes now called with Just Key and Just File.
It currently constructs a FileMatcher, ignoring the Key. However, if it
constructed a FileKeyMatcher, which contained both, then it might be
possible to speed up parts of Limit, which currently call the somewhat
expensive lookupFileKey to get the Key.

I have not made this optimisation yet, because I am not sure if the key is
always the same. Will need some significant checking to satisfy myself
that's the case..

1 files changed, 7 insertions, 10 deletions

diff --git a/Annex/Wanted.hs b/Annex/Wanted.hs
index 04dcc1c1c..42f813bbb 100644
--- a/Annex/Wanted.hs
+++ b/Annex/Wanted.hs
@@ -14,19 +14,16 @@ import Annex.UUID
 import qualified Data.Set as S
 
 {- Check if a file is preferred content for the local repository. -}
-wantGet :: Bool -> AssociatedFile -> Annex Bool
-wantGet def Nothing = return def
-wantGet def (Just file) = isPreferredContent Nothing S.empty file def
+wantGet :: Bool -> Maybe Key -> AssociatedFile -> Annex Bool
+wantGet def key file = isPreferredContent Nothing S.empty key file def
 
 {- Check if a file is preferred content for a remote. -}
-wantSend :: Bool -> AssociatedFile -> UUID -> Annex Bool
-wantSend def Nothing _ = return def
-wantSend def (Just file) to = isPreferredContent (Just to) S.empty file def
+wantSend :: Bool -> Maybe Key -> AssociatedFile -> UUID -> Annex Bool
+wantSend def key file to = isPreferredContent (Just to) S.empty key file def
 
 {- Check if a file can be dropped, maybe from a remote.
  - Don't drop files that are preferred content. -}
-wantDrop :: Bool -> Maybe UUID -> AssociatedFile -> Annex Bool
-wantDrop def _ Nothing = return $ not def
-wantDrop def from (Just file) = do
+wantDrop :: Bool -> Maybe UUID -> Maybe Key -> AssociatedFile -> Annex Bool
+wantDrop def from key file = do
 	u <- maybe getUUID (return . id) from
-	not <$> isPreferredContent (Just u) (S.singleton u) file def
+	not <$> isPreferredContent (Just u) (S.singleton u) key file def