implement GETCONFIG and SETCONFIG

Changed protocol spec to make SETCONFIG only store it persistently when run
during INITREMOTE. I see no reason to support storing it persistently at
other times, and doing so would unnecessarily complicate the code.

Also, letting that be done would probably result in use for storing data that
doesn't really belong there, and special remote authors who don't
understand how the union merging works would probably be surprised the
results.

3 files changed, 34 insertions, 19 deletions

diff --git a/Remote/External.hs b/Remote/External.hs
index 6180ced2a..18dd6b627 100644
--- a/Remote/External.hs
+++ b/Remote/External.hs
@@ -39,7 +39,7 @@ remote = RemoteType {
 
 gen :: Git.Repo -> UUID -> RemoteConfig -> RemoteGitConfig -> Annex (Maybe Remote)
 gen r u c gc = do
-	external <- newExternal externaltype
+	external <- newExternal externaltype c
 	Annex.addCleanup (fromUUID u) $ stopExternal external
 	cst <- getCost external r gc
 	return $ Just $ encryptableRemote c
@@ -76,14 +76,15 @@ externalSetup mu c = do
 		M.lookup "externaltype" c
 	c' <- encryptionSetup c
 
-	external <- newExternal externaltype
+	external <- newExternal externaltype c'
 	handleRequest external INITREMOTE Nothing $ \resp -> case resp of
 		INITREMOTE_SUCCESS -> Just noop
 		INITREMOTE_FAILURE errmsg -> Just $ error errmsg
 		_ -> Nothing
+	c'' <- liftIO $ atomically $ readTMVar $ externalConfig external
 
-	gitConfigSpecialRemote u c' "externaltype" externaltype
-	return (c', u)
+	gitConfigSpecialRemote u c'' "externaltype" externaltype
+	return (c'', u)
 
 store :: External -> Key -> AssociatedFile -> MeterUpdate -> Annex Bool
 store external k _f p = sendAnnex k rollback $ \f ->
@@ -201,8 +202,15 @@ handleRequest' lck external req mp responsehandler = do
 		maybe noop (\a -> liftIO $ a bytesprocessed) mp
 	handleRemoteRequest (DIRHASH k) = 
 		sendMessage lck external (VALUE $ hashDirMixed k)
-	handleRemoteRequest (SETCONFIG setting value) = error "TODO"
-	handleRemoteRequest (GETCONFIG setting) = error "TODO"
+	handleRemoteRequest (SETCONFIG setting value) =
+		liftIO $ atomically $ do
+			let v = externalConfig external
+			m <- takeTMVar v
+			putTMVar v $ M.insert setting value m
+	handleRemoteRequest (GETCONFIG setting) = do
+		value <- fromMaybe "" . M.lookup setting
+			<$> liftIO (atomically $ readTMVar $ externalConfig external)
+		sendMessage lck external (VALUE value)
 	handleRemoteRequest (SETSTATE k value) = error "TODO"
 	handleRemoteRequest (GETSTATE k) = error "TODO"
 	handleRemoteRequest (VERSION _) =
diff --git a/Remote/External/Types.hs b/Remote/External/Types.hs
index 4000f3f49..ff93af0ec 100644
--- a/Remote/External/Types.hs
+++ b/Remote/External/Types.hs
@@ -30,11 +30,12 @@ module Remote.External.Types (
 ) where
 
 import Common.Annex
-import Types.Key
-import Utility.Metered
-import Logs.Transfer
-import Config.Cost
 import Annex.Exception
+import Types.Key (file2key, key2file)
+import Utility.Metered (BytesProcessed(..))
+import Logs.Transfer (Direction(..))
+import Config.Cost (Cost)
+import Types.Remote (RemoteConfig)
 
 import Data.Char
 import Control.Concurrent.STM
@@ -47,13 +48,16 @@ data External = External
 	, externalState :: TMVar ExternalState
 	-- Empty when a remote is in use.
 	, externalLock :: TMVar ExternalLock
+	-- Never left empty.
+	, externalConfig :: TMVar RemoteConfig
 	}
 
-newExternal :: ExternalType -> Annex External
-newExternal externaltype = liftIO $ External
+newExternal :: ExternalType -> RemoteConfig -> Annex External
+newExternal externaltype c = liftIO $ External
 	<$> pure externaltype
 	<*> atomically newEmptyTMVar
 	<*> atomically (newTMVar ExternalLock)
+	<*> atomically (newTMVar c)
 
 type ExternalType = String
 
diff --git a/doc/design/external_special_remote_protocol.mdwn b/doc/design/external_special_remote_protocol.mdwn
index c27b50bfe..dd89e5074 100644
--- a/doc/design/external_special_remote_protocol.mdwn
+++ b/doc/design/external_special_remote_protocol.mdwn
@@ -177,14 +177,17 @@ in control.
   creating hash directory structures to store Keys in.  
   (git-annex replies with VALUE followed by the value.)
 * `SETCONFIG Setting`  
-  Sets one of the special remote's configuration settings. These settings
-  are stored in the git-annex branch, so will be available if the same
-  special remote is used elsewhere.  
-  (Typically only done during INITREMOTE, although it is accepted at other
-  times.)
+  Sets one of the special remote's configuration settings.  
+  Normally this is sent during INITREMOTE, which allows these settings
+  to be stored in the git-annex branch, so will be available if the same
+  special remote is used elsewhere. (If sent after INITREMOTE, the changed
+  configuration will only be available while the remote is running.)
 * `GETCONFIG Setting`  
-  Gets one of the special remote's configuration settings.  
-  (git-annex replies with VALUE followed by the value.)
+  Gets one of the special remote's configuration settings, which can have
+  been passed by the user when running `git annex initremote`, or
+  can have been set by a previous SETCONFIG. Can be run at any time.  
+  (git-annex replies with VALUE followed by the value. If the setting is
+  not set, the value will be empty.)
 * `SETSTATE Key Value`  
   git-annex can store state in the git-annex branch on a
   per-special-remote, per-key basis. This sets that state.