more lock file refactoring

Also fixes a test suite failures introduced in recent commits, where
inAnnexSafe failed in indirect mode, since it tried to open the lock file
ReadWrite. This is why the new checkLocked opens it ReadOnly.

This commit was sponsored by Chad Horohoe.

Annex/Content.hs

@@ -101,23 +101,21 @@ inAnnexSafe key = inAnnex' (fromMaybe False) (Just False) go key
 		=<< contentLockFile key
 
 #ifndef mingw32_HOST_OS
-	checkindirect f = liftIO $ openExistingLockFile f >>= check is_missing
+	checkindirect contentfile = liftIO $ checkOr is_missing contentfile
 	{- In direct mode, the content file must exist, but
-	 - the lock file often generally won't exist unless a removal is in
-	 - process. This does not create the lock file, it only checks for
-	 - it. -}
+	 - the lock file generally won't exist unless a removal is in
+	 - process. -}
 	checkdirect contentfile lockfile = liftIO $
 		ifM (doesFileExist contentfile)
-			( openExistingLockFile lockfile >>= check is_unlocked
+			( checkOr is_unlocked lockfile
 			, return is_missing
 			)
-	check _ (Just h) = do
-		v <- getLock h (ReadLock, AbsoluteSeek, 0, 0)
-		closeFd h
+	checkOr def lockfile = do
+		v <- checkLocked lockfile
 		return $ case v of
-			Just _ -> is_locked
-			Nothing -> is_unlocked
-	check def Nothing = return def
+			Nothing -> def
+			Just True -> is_locked
+			Just False -> is_unlocked
 #else
 	checkindirect f = liftIO $ ifM (doesFileExist f)
 		( do
@@ -161,7 +159,7 @@ lockContent key a = do
 	contentfile <- calcRepo $ gitAnnexLocation key
 	lockfile <- contentLockFile key
 	maybe noop setuplockfile lockfile
-	bracket (liftIO $ lock contentfile lockfile) (unlock lockfile) (const a)
+	bracket (lock contentfile lockfile) (unlock lockfile) (const a)
   where
 	alreadylocked = error "content is locked"
 	setuplockfile lockfile = modifyContent lockfile $
@@ -171,8 +169,11 @@ lockContent key a = do
 		void $ liftIO $ tryIO $
 			nukeFile lockfile
 #ifndef mingw32_HOST_OS
-	lock contentfile Nothing = opencontentforlock contentfile >>= dolock
-	lock _ (Just lockfile) = createLockFile Nothing lockfile >>= dolock . Just
+	lock contentfile Nothing = liftIO $
+		opencontentforlock contentfile >>= dolock
+	lock _ (Just lockfile) = do
+		mode <- annexFileMode
+		liftIO $ createLockFile mode lockfile >>= dolock . Just
 	{- Since content files are stored with the write bit disabled, have
 	 - to fiddle with permissions to open for an exclusive lock. -}
 	opencontentforlock f = catchDefaultIO Nothing $ 
@@ -189,7 +190,8 @@ lockContent key a = do
 		maybe noop cleanuplockfile mlockfile
 		liftIO $ maybe noop closeFd mfd
 #else
-	lock _ (Just lockfile) = maybe alreadylocked (return . Just) =<< lockExclusive lockfile
+	lock _ (Just lockfile) = liftIO $
+		maybe alreadylocked (return . Just) =<< lockExclusive lockfile
 	lock _ Nothing = return Nothing
 	unlock mlockfile mlockhandle = do
 		liftIO $ maybe noop dropLock mlockhandle