look up --to and --from remote names only once

This will speed up commands like move and drop.

Command/Copy.hs

@@ -10,17 +10,19 @@ module Command.Copy where
 import Common.Annex
 import Command
 import qualified Command.Move
+import qualified Remote
 
 def :: [Command]
 def = [withOptions Command.Move.options $ command "copy" paramPaths seek
 	"copy content of files to/from another repository"]
 
 seek :: [CommandSeek]
-seek = [withField "to" id $ \to -> withField "from" id $ \from ->
+seek = [withField "to" Remote.byName $ \to ->
-		withNumCopies $ \n -> whenAnnexed $ start to from n]
+		withField "from" Remote.byName $ \from ->
+			withNumCopies $ \n -> whenAnnexed $ start to from n]
 
 -- A copy is just a move that does not delete the source file.
 -- However, --auto mode avoids unnecessary copies.
-start :: Maybe String -> Maybe String -> Maybe Int -> FilePath -> (Key, Backend) -> CommandStart
+start :: Maybe Remote -> Maybe Remote -> Maybe Int -> FilePath -> (Key, Backend) -> CommandStart
 start to from numcopies file (key, backend) = autoCopies key (<) numcopies $
 	Command.Move.start to from False file (key, backend)

Command/Drop.hs

@@ -25,15 +25,14 @@ fromOption :: Option
 fromOption = fieldOption ['f'] "from" paramRemote "drop content from a remote"
 
 seek :: [CommandSeek]
-seek = [withField "from" id $ \from -> withNumCopies $ \n ->
+seek = [withField "from" Remote.byName $ \from -> withNumCopies $ \n ->
 	whenAnnexed $ start from n]
 
-start :: Maybe String -> Maybe Int -> FilePath -> (Key, Backend) -> CommandStart
+start :: Maybe Remote -> Maybe Int -> FilePath -> (Key, Backend) -> CommandStart
 start from numcopies file (key, _) = autoCopies key (>) numcopies $ do
 	case from of
 		Nothing -> startLocal file numcopies key
-		Just name -> do
+		Just remote -> do
-			remote <- Remote.byName name
 			u <- getUUID
 			if Remote.uuid remote == u
 				then startLocal file numcopies key

Command/DropUnused.hs

@@ -51,10 +51,9 @@ start (unused, unusedbad, unusedtmp) s = search
 					next $ a key
 
 perform :: Key -> CommandPerform
-perform key = maybe droplocal dropremote =<< Annex.getField "from"
+perform key = maybe droplocal dropremote =<< Remote.byName =<< Annex.getField "from"
 	where
-		dropremote name = do
+		dropremote r = do
-			r <- Remote.byName name
 			showAction $ "from " ++ Remote.name r
 			ok <- Remote.removeKey r key
 			next $ Command.Drop.cleanupRemote key r ok

Command/Find.hs

@@ -33,7 +33,7 @@ seek :: [CommandSeek]
 seek = [withField "format" formatconverter $ \f ->
 		withFilesInGit $ whenAnnexed $ start f]
 	where
-		formatconverter = maybe Nothing (Just . Utility.Format.gen)
+		formatconverter = return . maybe Nothing (Just . Utility.Format.gen)
 
 start :: Maybe Utility.Format.Format -> FilePath -> (Key, Backend) -> CommandStart
 start format file (key, _) = do

Command/Get.hs

@@ -18,17 +18,16 @@ def = [withOptions [Command.Move.fromOption] $ command "get" paramPaths seek
 	"make content of annexed files available"]
 
 seek :: [CommandSeek]
-seek = [withField "from" id $ \from -> withNumCopies $ \n ->
+seek = [withField "from" Remote.byName $ \from -> withNumCopies $ \n ->
 	whenAnnexed $ start from n]
 
-start :: Maybe String -> Maybe Int -> FilePath -> (Key, Backend) -> CommandStart
+start :: Maybe Remote -> Maybe Int -> FilePath -> (Key, Backend) -> CommandStart
 start from numcopies file (key, _) = stopUnless (not <$> inAnnex key) $
 	autoCopies key (<) numcopies $ do
 		case from of
 			Nothing -> go $ perform key
-			Just name -> do
+			Just src -> do
 				-- get --from = copy --from
-				src <- Remote.byName name
 				stopUnless (Command.Move.fromOk src key) $
 					go $ Command.Move.fromPerform src False key
 	where

Command/Move.hs

@@ -29,20 +29,17 @@ options :: [Option]
 options = [fromOption, toOption]
 
 seek :: [CommandSeek]
-seek = [withField "to" id $ \to -> withField "from" id $ \from ->
+seek = [withField "to" Remote.byName $ \to ->
-		withFilesInGit $ whenAnnexed $ start to from True]
+		withField "from" Remote.byName $ \from ->
+			withFilesInGit $ whenAnnexed $ start to from True]
 
-start :: Maybe String -> Maybe String -> Bool -> FilePath -> (Key, Backend) -> CommandStart
+start :: Maybe Remote -> Maybe Remote -> Bool -> FilePath -> (Key, Backend) -> CommandStart
 start to from move file (key, _) = do
 	noAuto
 	case (from, to) of
 		(Nothing, Nothing) -> error "specify either --from or --to"
-		(Nothing, Just name) -> do
+		(Nothing, Just dest) -> toStart dest move file key
-			dest <- Remote.byName name
+		(Just src, Nothing) -> fromStart src move file key
-			toStart dest move file key
-		(Just name, Nothing) -> do
-			src <- Remote.byName name
-			fromStart src move file key
 		(_ ,  _) -> error "only one of --from or --to can be specified"
 	where
 		noAuto = when move $ whenM (Annex.getState Annex.auto) $ error

Command/Sync.hs

@@ -61,7 +61,7 @@ syncRemotes rs = do
 		wanted
 			| null rs = good =<< available
 			| otherwise = listed
-		listed = mapM Remote.byName rs
+		listed = catMaybes <$> mapM (Remote.byName . Just) rs
 		available = filter nonspecial <$> Remote.enabledRemoteList
 		good = filterM $ Remote.Git.repoAvail . Types.Remote.repo
 		nonspecial r = Types.Remote.remotetype r == Remote.Git.remote

Command/Unused.hs

@@ -66,7 +66,7 @@ checkUnused = do
 
 checkRemoteUnused :: String -> CommandPerform
 checkRemoteUnused name = do
-	checkRemoteUnused' =<< Remote.byName name
+	checkRemoteUnused' =<< fromJust <$> Remote.byName (Just name)
 	next $ return True
 
 checkRemoteUnused' :: Remote -> Annex ()

Remote.hs

@@ -94,14 +94,15 @@ enabledRemoteList = filterM (repoNotIgnored . repo) =<< remoteList
 remoteMap :: Annex (M.Map UUID String)
 remoteMap = M.fromList . map (\r -> (uuid r, name r)) <$> remoteList
 
-{- Looks up a remote by name. (Or by UUID.) Only finds currently configured
+{- When a name is specified, looks up the remote matching that name.
- - git remotes. -}
+ - (Or it can be a UUID.) Only finds currently configured git remotes. -}
-byName :: String -> Annex (Remote)
+byName :: Maybe String -> Annex (Maybe Remote)
-byName n = do
+byName Nothing = return Nothing
+byName (Just n) = do
 	res <- byName' n
 	case res of
 		Left e -> error e
-		Right r -> return r
+		Right r -> return $ Just r
 byName' :: String -> Annex (Either String Remote)
 byName' "" = return $ Left "no remote specified"
 byName' n = do

Seek.hs

@@ -91,9 +91,9 @@ withKeys a params = return $ map (a . parse) params
  - a conversion function, and then is passed into the seek action.
  - This ensures that the conversion function only runs once.
  -}
-withField :: String -> (Maybe String -> a) -> (a -> CommandSeek) -> CommandSeek
+withField :: String -> (Maybe String -> Annex a) -> (a -> CommandSeek) -> CommandSeek
 withField field converter a ps = do
-        f <- converter <$> Annex.getField field
+        f <- converter =<< Annex.getField field
         a f ps
 
 withNothing :: CommandStart -> CommandSeek