get, move, copy: Now refuse to do anything when the requested file transfer is already in progress by another process.

Note this is per-remote, so trying to get the same file from multiple
remotes can still let duplicate downloads run. (And uploading the same file
to multiple remotes is not duplicate at all of course.)

get, move, and copy are the only git-annex subcommands that transfer
files, but there's still git-annex-shell recvkey and sendkey to deal with too.

I considered modifying retrieveKeyFile or getViaTmp, but they are called
by other code that does not involve expensive file transfers (migrate)
or that does file transfers that should not be checked by this (fsck --from).

1 files changed, 10 insertions, 9 deletions

diff --git a/Command/Get.hs b/Command/Get.hs
index c4ba48312..35e25d975 100644
--- a/Command/Get.hs
+++ b/Command/Get.hs
@@ -12,6 +12,7 @@ import Command
 import qualified Remote
 import Annex.Content
 import qualified Command.Move
+import Logs.Transfer
 
 def :: [Command]
 def = [withOptions [Command.Move.fromOption] $ command "get" paramPaths seek
@@ -25,24 +26,24 @@ start :: Maybe Remote -> FilePath -> (Key, Backend) -> CommandStart
 start from file (key, _) = stopUnless (not <$> inAnnex key) $
 	autoCopies file key (<) $ \_numcopies ->
 		case from of
-			Nothing -> go $ perform key
+			Nothing -> go $ perform key file
 			Just src ->
 				-- get --from = copy --from
 				stopUnless (Command.Move.fromOk src key) $
-					go $ Command.Move.fromPerform src False key
+					go $ Command.Move.fromPerform src False key file
 	where
 		go a = do
 			showStart "get" file
-			next a	
+			next a
 
-perform :: Key -> CommandPerform
-perform key = stopUnless (getViaTmp key $ getKeyFile key) $
+perform :: Key -> FilePath -> CommandPerform
+perform key file = stopUnless (getViaTmp key $ getKeyFile key file) $
 	next $ return True -- no cleanup needed
 
 {- Try to find a copy of the file in one of the remotes,
  - and copy it to here. -}
-getKeyFile :: Key -> FilePath -> Annex Bool
-getKeyFile key file = dispatch =<< Remote.keyPossibilities key
+getKeyFile :: Key -> FilePath -> FilePath -> Annex Bool
+getKeyFile key file dest = dispatch =<< Remote.keyPossibilities key
 	where
 		dispatch [] = do
 			showNote "not available"
@@ -64,7 +65,7 @@ getKeyFile key file = dispatch =<< Remote.keyPossibilities key
 			| Remote.hasKeyCheap r =
 				either (const False) id <$> Remote.hasKey r key
 			| otherwise = return True
-		docopy r continue = do
+		docopy r continue = download r key file $ do
 			showAction $ "from " ++ Remote.name r
-			ifM (Remote.retrieveKeyFile r key file)
+			ifM (Remote.retrieveKeyFile r key dest)
 				( return True , continue)