update

Annex.hs

@@ -44,14 +44,30 @@ annexFile state file = do
 			gitAdd (repo state) file
 		checkExists file = do
 			exists <- doesFileExist file
-			case (exists) of
-				False -> error $ "does not exist: " ++ file
-				True -> return ()
+			if (not exists)
+				then error $ "does not exist: " ++ file
+				else return ()
 		checkLegal file = do
-			s <- getFileStatus file
-			case (not (isSymbolicLink s) && not (isRegularFile s)) of
-				False -> error $ "not a regular file: " ++ file
-				True -> return ()
+			s <- getSymbolicLinkStatus file
+			if ((isSymbolicLink s) || (not $ isRegularFile s))
+				then error $ "not a regular file: " ++ file
+				else return ()
+
+{- Inverse of annexFile. -}
+unannexFile :: State -> FilePath -> IO ()
+unannexFile state file = do
+	alreadyannexed <- lookupBackend (backends state) (repo state) file
+	case (alreadyannexed) of
+		Nothing -> error $ "not annexed " ++ file
+		Just _ -> do
+			mkey <- dropFile (backends state) (repo state) file
+			case (mkey) of
+				Nothing -> return ()
+				Just key -> do
+					src <- annexDir (repo state) key
+					removeFile file
+					renameFile src file
+					return ()
 
 {- Sets up a git repo for git-annex. May be called repeatedly. -}
 gitPrep :: GitRepo -> IO ()

Backend.hs

@@ -57,14 +57,29 @@ storeFile (b:bs) repo file = do
 
 {- Attempts to retrieve an file from one of the backends, saving it to
  - a specified location. -}
-retrieveFile :: [Backend] -> GitRepo -> FilePath -> FilePath -> IO (Bool)
+retrieveFile :: [Backend] -> GitRepo -> FilePath -> FilePath -> IO Bool
 retrieveFile backends repo file dest = do
 	result <- lookupBackend backends repo file
 	case (result) of
 		Nothing -> return False
-		Just b -> (retrieveKeyFile b) key dest
-			where
-				key = readFile (backendFile b repo file)
+		Just b -> do
+			key <- lookupKey b repo file
+			(retrieveKeyFile b) key dest
+
+{- Drops the key for a file from the backend that has it. -}
+dropFile :: [Backend] -> GitRepo -> FilePath -> IO (Maybe Key)
+dropFile backends repo file = do
+	result <- lookupBackend backends repo file
+	case (result) of
+		Nothing -> return Nothing
+		Just b -> do
+			key <- lookupKey b repo file
+			(removeKey b) key
+			return $ Just key
+
+{- Looks up the key a backend uses for an already annexed file. -}
+lookupKey :: Backend -> GitRepo -> FilePath -> IO Key
+lookupKey backend repo file = readFile (backendFile backend repo file)
 
 {- Looks up the backend used for an already annexed file. -}
 lookupBackend :: [Backend] -> GitRepo -> FilePath -> IO (Maybe Backend)

BackendFile.hs

@@ -9,7 +9,8 @@ backend = Backend {
 	name = "file",
 	getKey = keyValue,
 	storeFileKey = dummyStore,
-	retrieveKeyFile = copyFromOtherRepo
+	retrieveKeyFile = copyFromOtherRepo,
+	removeKey = dummyRemove
 }
 
 -- direct mapping from filename to key
@@ -18,11 +19,14 @@ keyValue repo file = return $ Just file
 
 {- This backend does not really do any independant data storage,
  - it relies on the file contents in .git/annex/ in this repo,
- - and other accessible repos. So storing a file is a no-op. -}
+ - and other accessible repos. So storing or removing a key is
+ - a no-op. -}
 dummyStore :: GitRepo -> FilePath -> Key -> IO (Bool)
 dummyStore repo file key = return True
+dummyRemove :: Key -> IO Bool
+dummyRemove url = return False
 
 {- Try to find a copy of the file in one of the other repos,
  - and copy it over to this one. -}
-copyFromOtherRepo :: IO Key -> FilePath -> IO (Bool)
+copyFromOtherRepo :: Key -> FilePath -> IO (Bool)
 copyFromOtherRepo key file = error "copyFromOtherRepo unimplemented" -- TODO

BackendUrl.hs

@@ -9,16 +9,19 @@ backend = Backend {
 	name = "url",
 	getKey = keyValue,
 	storeFileKey = dummyStore,
-	retrieveKeyFile = downloadUrl
+	retrieveKeyFile = downloadUrl,
+	removeKey = dummyRemove
 }
 
 -- cannot generate url from filename
 keyValue :: GitRepo -> FilePath -> IO (Maybe Key)
 keyValue repo file = return Nothing
 
--- cannot store to urls
-dummyStore :: GitRepo -> FilePath -> Key -> IO (Bool)
+-- cannot change urls
+dummyStore :: GitRepo -> FilePath -> Key -> IO Bool
 dummyStore repo file url = return False
+dummyRemove :: Key -> IO Bool
+dummyRemove url = return False
 
-downloadUrl :: IO Key -> FilePath -> IO (Bool)
+downloadUrl :: Key -> FilePath -> IO Bool
 downloadUrl url file = error "downloadUrl unimplemented"

CmdLine.hs

@@ -10,8 +10,8 @@ import System.Console.GetOpt
 import Types
 import Annex
 
-data Flag = Add FilePath | Push String | Pull String |
-		Want FilePath | Get (Maybe FilePath) | Drop FilePath
+data Flag = Add FilePath | Push String | Pull String | Want FilePath | 
+		Get (Maybe FilePath) | Drop FilePath | Unannex FilePath
 	deriving Show
 
 options :: [OptDescr Flag]
@@ -22,6 +22,7 @@ options =
 	, Option ['w'] ["want"] (ReqArg Want "FILE") "request file contents"
 	, Option ['g'] ["get"] (OptArg Get "FILE") "transfer file contents"
 	, Option ['d'] ["drop"] (ReqArg Drop "FILE") "indicate file content not needed"
+	, Option ['u'] ["unannex"] (ReqArg Unannex "FILE") "undo --add"
 	]
 
 argvToFlags argv = do
@@ -38,4 +39,5 @@ dispatch :: Flag -> State -> IO ()
 dispatch flag state = do
 	case (flag) of
 		Add f -> annexFile state f
+		Unannex f -> unannexFile state f
 		_ -> error "not implemented"

Types.hs

@@ -13,9 +13,11 @@ data Backend = Backend {
 	-- converts a filename to a key
 	getKey :: GitRepo -> FilePath -> IO (Maybe Key),
 	-- stores a file's contents to a key
-	storeFileKey :: GitRepo -> FilePath -> Key -> IO (Bool),
+	storeFileKey :: GitRepo -> FilePath -> Key -> IO Bool,
 	-- retrieves a key's contents to a file
-	retrieveKeyFile :: IO Key -> FilePath -> IO (Bool)
+	retrieveKeyFile :: Key -> FilePath -> IO Bool,
+	-- removes a key
+	removeKey :: Key -> IO Bool
 }
 
 -- a git repository

git-annex.mdwn

@@ -36,6 +36,7 @@ Enough broad picture, here's how it actually looks:
   downloaded.
 * `git annex --drop $file` indicates that you no longer want the file's
   content to be available in this repository.
+* `git annex --unannex $file` undoes a `git annex --add`.
 * `git annex $file` is a shorthand for either --add or --get. If the file
   is already known, it does --get, otherwise it does --add.