fold parseLinkTarget into parseLinkTargetOrPointer

Only one place remained that differentiated between them.

It is the case that a symlink target that happens to contain a newline
somehow will be treated as a link to a key truncated at the newline.
This is super unlikely to happen, and since a key cannot actually
contain a newline, it's as good a behavior as any. Anyway, this commit
does not change the behavior there, although arguably it should be
changed. Note that getAnnexLinkTarget does prevent a symlink target
containing a newline.

Sponsored-by: Dartmouth College's Datalad project

Annex/Link.hs

@@ -7,7 +7,7 @@
  -
  - Pointer files are used instead of symlinks for unlocked files.
  -
- - Copyright 2013-2021 Joey Hess <id@joeyh.name>
+ - Copyright 2013-2022 Joey Hess <id@joeyh.name>
  -
  - Licensed under the GNU AGPL version 3 or higher.
  -}
@@ -297,12 +297,22 @@ unableToRestage mf = unwords
 
 {- Parses a symlink target or a pointer file to a Key. -}
 parseLinkTargetOrPointer :: S.ByteString -> Maybe Key
-parseLinkTargetOrPointer = parseLinkTarget . S8.takeWhile (not . lineend)
+parseLinkTargetOrPointer = go . S8.takeWhile (not . lineend)
   where
+	go l
+		| isLinkToAnnex l = fileKey $ snd $ S8.breakEnd pathsep l
+		| otherwise = Nothing
+	
 	lineend '\n' = True
 	lineend '\r' = True
 	lineend _ = False
 	
+	pathsep '/' = True
+#ifdef mingw32_HOST_OS
+	pathsep '\\' = True
+#endif
+	pathsep _ = False
+
 {- Avoid looking at more of the lazy ByteString than necessary since it
  - could be reading from a large file that is not a pointer file. -}
 parseLinkTargetOrPointerLazy :: L.ByteString -> Maybe Key
@@ -310,18 +320,6 @@ parseLinkTargetOrPointerLazy b =
 	let b' = L.take (fromIntegral maxPointerSz) b
 	in parseLinkTargetOrPointer (L.toStrict b')
 
-{- Parses a symlink target to a Key. -}
-parseLinkTarget :: S.ByteString -> Maybe Key
-parseLinkTarget l
-	| isLinkToAnnex l = fileKey $ snd $ S8.breakEnd pathsep l
-	| otherwise = Nothing
-  where
-	pathsep '/' = True
-#ifdef mingw32_HOST_OS
-	pathsep '\\' = True
-#endif
-	pathsep _ = False
-
 formatPointer :: Key -> S.ByteString
 formatPointer k = prefix <> keyFile k <> nl
   where

Assistant/Threads/Watcher.hs

@@ -265,7 +265,7 @@ onAddFile' contentchanged addassociatedfile addlink samefilestatus symlinkssuppo
 			case linktarget of
 				Nothing -> a
 				Just lt -> do
-					case parseLinkTarget lt of
+					case parseLinkTargetOrPointer lt of
 						Nothing -> noop
 						Just key -> liftAnnex $
 							addassociatedfile key file