checkpresentkey: New plumbing command to check if a key can be verified to be present on a remote.

Command/CheckPresentKey.hs

@@ -0,0 +1,36 @@
+{- git-annex command
+ -
+ - Copyright 2015 Joey Hess <id@joeyh.name>
+ -
+ - Licensed under the GNU GPL version 3 or higher.
+ -}
+
+module Command.CheckPresentKey where
+
+import Common.Annex
+import Command
+import Types.Key
+import qualified Remote
+import Annex
+import Types.Messages
+
+cmd :: [Command]
+cmd = [noCommit $ command "checkpresentkey" (paramPair paramKey paramRemote) seek
+	SectionPlumbing "check if key is present in remote"] 
+
+seek :: CommandSeek
+seek = withWords start
+
+start :: [String] -> CommandStart
+start (ks:rn:[]) = do
+	setOutput QuietOutput
+	maybe (error "Unknown remote") (go <=< flip Remote.hasKey k)
+		=<< Remote.byNameWithUUID (Just rn)
+  where
+	k = fromMaybe (error "bad key") (file2key ks)
+	go (Right True) = liftIO exitSuccess
+	go (Right False) = liftIO exitFailure
+	go (Left e) = liftIO $ do
+		hPutStrLn stderr e
+		exitWith $ ExitFailure 100
+start _ = error "Wrong number of parameters"