refactor and improve pointer file handling code

Annex/CatFile.hs

@@ -14,7 +14,6 @@ module Annex.CatFile (
 	catFileHandle,
 	catFileStop,
 	catKey,
-	parsePointer,
 	catKeyFile,
 	catKeyFileHEAD,
 	catSymLinkTarget,
@@ -31,7 +30,7 @@ import qualified Annex
 import Git.Types
 import Git.FilePath
 import qualified Git.Ref
-import Types.Key
+import Annex.Link
 
 catFile :: Git.Branch -> FilePath -> Annex L.ByteString
 catFile branch file = do
@@ -83,22 +82,7 @@ catFileStop = do
 
 {- From ref to a symlink or a pointer file, get the key. -}
 catKey :: Ref -> Annex (Maybe Key)
-catKey ref = parsePointer . fromInternalGitPath . decodeBS . L.take maxsz 
-	<$> catObject ref
-  where
-	-- Want to avoid buffering really big files in git into memory.
-	-- 8192 bytes is plenty for a pointer to a key.
-	-- Pad some more to allow for any pointer files that might have
-	-- lines after the key explaining what the file is used for.
-	maxsz = 81920
-
-{- Only look at the first line of a pointer file. -}
-parsePointer :: String -> Maybe Key
-parsePointer s = headMaybe (lines s) >>= go
-  where
-	go l
-		| isLinkToAnnex l = file2key $ takeFileName l
-		| otherwise = Nothing
+catKey ref = parseLinkOrPointer <$> catObject ref
 
 {- Gets a symlink target. -}
 catSymLinkTarget :: Sha -> Annex String

Annex/Init.hs

@@ -29,11 +29,11 @@ import Types.TrustLevel
 import Annex.Version
 import Annex.Difference
 import Annex.UUID
+import Annex.Link
 import Config
 import Annex.Direct
 import Annex.Content.Direct
 import Annex.Environment
-import Backend
 import Annex.Hook
 import Upgrade
 #ifndef mingw32_HOST_OS

Annex/Link.hs

@@ -5,7 +5,9 @@
  - On other filesystems, git instead stores the symlink target in a regular
  - file.
  -
- - Copyright 2013 Joey Hess <id@joeyh.name>
+ - Pointer files are used instead of symlinks for unlocked files.
+ -
+ - Copyright 2013-2015 Joey Hess <id@joeyh.name>
  -
  - Licensed under the GNU GPL version 3 or higher.
  -}
@@ -19,6 +21,9 @@ import qualified Git.UpdateIndex
 import qualified Annex.Queue
 import Git.Types
 import Git.FilePath
+import Types.Key
+
+import qualified Data.ByteString.Lazy as L
 
 type LinkTarget = String
 
@@ -110,3 +115,32 @@ stageSymlink :: FilePath -> Sha -> Annex ()
 stageSymlink file sha =
 	Annex.Queue.addUpdateIndex =<<
 		inRepo (Git.UpdateIndex.stageSymlink file sha)
+
+{- Parses a symlink target or a pointer file to a Key.
+ - Only looks at the first line, as pointer files can have subsequent
+ - lines. -}
+parseLinkOrPointer :: L.ByteString -> Maybe Key
+parseLinkOrPointer = parseLinkOrPointer' . decodeBS . L.take maxsz
+  where
+	{- Want to avoid buffering really big files in git into
+	 - memory when reading files that may be pointers.
+	 -
+	 - 8192 bytes is plenty for a pointer to a key.
+	 - Pad some more to allow for any pointer files that might have
+	 - lines after the key explaining what the file is used for. -}
+	maxsz = 81920
+
+parseLinkOrPointer' :: String -> Maybe Key
+parseLinkOrPointer' s = headMaybe (lines (fromInternalGitPath s)) >>= go
+  where
+	go l
+		| isLinkToAnnex l = file2key $ takeFileName l
+		| otherwise = Nothing
+
+formatPointer :: Key -> String
+formatPointer k = toInternalGitPath $ pathSeparator:objectDir </> key2file k
+
+{- Checks if a file is a pointer to a key. -}
+isPointerFile :: FilePath -> Annex (Maybe Key)
+isPointerFile f = liftIO $ catchDefaultIO Nothing $ 
+	parseLinkOrPointer <$> L.readFile f

Backend.hs

@@ -11,7 +11,6 @@ module Backend (
 	genKey,
 	lookupFile,
 	getBackend,
-	isAnnexLink,
 	chooseBackend,
 	lookupBackendName,
 	maybeLookupBackendName,

Command/Smudge.hs

@@ -9,16 +9,14 @@ module Command.Smudge where
 
 import Common.Annex
 import Command
-import Types.Key
 import Annex.Content
-import Annex.CatFile
+import Annex.Link
 import Annex.MetaData
 import Annex.FileMatcher
 import Types.KeySource
 import Backend
 import Logs.Location
 import qualified Database.AssociatedFiles as AssociatedFiles
-import Git.FilePath
 
 import qualified Data.ByteString.Lazy as B
 
@@ -46,16 +44,13 @@ seek o = commandAction $
 -- available annex object, should output its content.
 smudge :: FilePath -> CommandStart
 smudge file = do
-	liftIO $ fileEncoding stdin
-	s <- liftIO $ hGetContents stdin
-	case parsePointer s of
-		Nothing -> liftIO $ putStr s
+	b <- liftIO $ B.hGetContents stdin
+	case parseLinkOrPointer b of
+		Nothing -> liftIO $ B.putStr b
 		Just k -> do
 			updateAssociatedFiles k file
 			content <- calcRepo (gitAnnexLocation k)
-			liftIO $ maybe
-				(putStr s)
-				(B.hPut stdout)
+			liftIO $ B.hPut stdout . fromMaybe b
 				=<< catchMaybeIO (B.readFile content)
 	stop
 
@@ -102,11 +97,8 @@ ingest file = do
 		=<< liftIO (getFileStatus file)
 	return k
 
--- Could add a newline and some text explaining this file is a pointer.
--- parsePointer only looks at the first line.
 emitPointer :: Key -> IO ()
-emitPointer k = putStrLn $ toInternalGitPath $
-	pathSeparator:objectDir </> key2file k
+emitPointer = putStrLn . formatPointer
 
 updateAssociatedFiles :: Key -> FilePath -> Annex ()
 updateAssociatedFiles k f = do