add lockContentShared

Also, rename lockContent to lockContentExclusive

inAnnexSafe should perhaps be eliminated, and instead use
`lockContentShared inAnnex`. However, I'm waiting on that, as there are
only 2 call sites for inAnnexSafe and it's fiddly.

Command/Drop.hs

@@ -88,12 +88,12 @@ startRemote afile numcopies key remote = do
 	showStart' ("drop " ++ Remote.name remote) key afile
 	next $ performRemote key afile numcopies remote
 
--- Note that lockContent is called before checking if the key is present
--- on enough remotes to allow removal. This avoids a scenario where two
+-- Note that lockContentExclusive is called before checking if the key is
+-- present on enough remotes to allow removal. This avoids a scenario where two
 -- or more remotes are trying to remove a key at the same time, and each
 -- see the key is present on the other.
 performLocal :: Key -> AssociatedFile -> NumCopies -> Maybe Remote -> CommandPerform
-performLocal key afile numcopies knownpresentremote = lockContent key $ \contentlock -> do
+performLocal key afile numcopies knownpresentremote = lockContentExclusive key $ \contentlock -> do
 	(remotes, trusteduuids) <- Remote.keyPossibilitiesTrusted key
 	let trusteduuids' = case knownpresentremote of
 		Nothing -> trusteduuids

Command/DropKey.hs

@@ -31,7 +31,7 @@ start key = stopUnless (inAnnex key) $ do
 	next $ perform key
 
 perform :: Key -> CommandPerform
-perform key = lockContent key $ \contentlock -> do
+perform key = lockContentExclusive key $ \contentlock -> do
 	removeAnnex contentlock
 	next $ cleanup key
 

Command/Move.hs

@@ -123,7 +123,7 @@ toPerform dest move key afile fastcheck isthere =
 			finish
   where
 	finish
-		| move = lockContent key $ \contentlock -> do
+		| move = lockContentExclusive key $ \contentlock -> do
 			removeAnnex contentlock
 			next $ Command.Drop.cleanupLocal key
 		| otherwise = next $ return True

Command/TestRemote.hs

@@ -120,7 +120,7 @@ test st r k =
 	, check "storeKey when already present" store
 	, present True
 	, check "retrieveKeyFile" $ do
-		lockContent k removeAnnex
+		lockContentExclusive k removeAnnex
 		get
 	, check "fsck downloaded object" fsck
 	, check "retrieveKeyFile resume from 33%" $ do
@@ -130,20 +130,20 @@ test st r k =
 			sz <- hFileSize h
 			L.hGet h $ fromInteger $ sz `div` 3
 		liftIO $ L.writeFile tmp partial
-		lockContent k removeAnnex
+		lockContentExclusive k removeAnnex
 		get
 	, check "fsck downloaded object" fsck
 	, check "retrieveKeyFile resume from 0" $ do
 		tmp <- prepTmp k
 		liftIO $ writeFile tmp ""
-		lockContent k removeAnnex
+		lockContentExclusive k removeAnnex
 		get
 	, check "fsck downloaded object" fsck
 	, check "retrieveKeyFile resume from end" $ do
 		loc <- Annex.calcRepo (gitAnnexLocation k)
 		tmp <- prepTmp k
 		void $ liftIO $ copyFileExternal CopyAllMetaData loc tmp
-		lockContent k removeAnnex
+		lockContentExclusive k removeAnnex
 		get
 	, check "fsck downloaded object" fsck
 	, check "removeKey when present" remove
@@ -189,7 +189,7 @@ testUnavailable st r k =
 cleanup :: [Remote] -> [Key] -> Bool -> CommandCleanup
 cleanup rs ks ok = do
 	forM_ rs $ \r -> forM_ ks (Remote.removeKey r)
-	forM_ ks $ \k -> lockContent k removeAnnex
+	forM_ ks $ \k -> lockContentExclusive k removeAnnex
 	return ok
 
 chunkSizes :: Int -> Bool -> [Int]

Command/Uninit.hs

@@ -105,7 +105,7 @@ removeUnannexed = go []
 	go c [] = return c
 	go c (k:ks) = ifM (inAnnexCheck k $ liftIO . enoughlinks)
 		( do
-			lockContent k removeAnnex
+			lockContentExclusive k removeAnnex
 			go c ks
 		, go (k:c) ks
 		)