factored out some useful error catching methods

2 files changed, 9 insertions, 13 deletions

diff --git a/Annex/Branch.hs b/Annex/Branch.hs
index 189289ad3..6c28a0c84 100644
--- a/Annex/Branch.hs
+++ b/Annex/Branch.hs
@@ -295,10 +295,8 @@ setJournalFile file content = do
 
 {- Gets any journalled content for a file in the branch. -}
 getJournalFile :: FilePath -> Annex (Maybe String)
-getJournalFile file = do
-	g <- gitRepo
-	liftIO $ catch (liftM Just . readFileStrict $ journalFile g file)
-		(const $ return Nothing)
+getJournalFile file = inRepo $ \g -> catchMaybeIO $
+	readFileStrict $ journalFile g file
 
 {- List of files that have updated content in the journal. -}
 getJournalledFiles :: Annex [FilePath]
@@ -308,8 +306,8 @@ getJournalledFiles = map fileJournal <$> getJournalFiles
 getJournalFiles :: Annex [FilePath]
 getJournalFiles = do
 	g <- gitRepo
-	fs <- liftIO $ catch (getDirectoryContents $ gitAnnexJournalDir g)
-		(const $ return [])
+	fs <- liftIO $
+		catchDefaultIO (getDirectoryContents $ gitAnnexJournalDir g) []
 	return $ filter (`notElem` [".", ".."]) fs
 
 {- Stages the specified journalfiles. -}
diff --git a/Annex/Content.hs b/Annex/Content.hs
index f50616af9..7586bb96f 100644
--- a/Annex/Content.hs
+++ b/Annex/Content.hs
@@ -83,19 +83,17 @@ lockContent key a = do
 		unlock (Just l) = closeFd l
 
 openForLock :: FilePath -> Bool -> IO (Maybe Fd)
-openForLock file writelock = bracket_ prep cleanup $
-	catch (Just <$> openFd file mode Nothing defaultFileFlags)
-		(const $ return Nothing)
+openForLock file writelock = bracket_ prep cleanup go
 	where
+		go = catchMaybeIO $ openFd file mode Nothing defaultFileFlags
 		mode = if writelock then ReadWrite else ReadOnly
 		{- Since files are stored with the write bit disabled,
 		 - have to fiddle with permissions to open for an
-		 - exclusive lock. flock locking would avoid this,
-		 - but -}
-		prep = forwritelock $ allowWrite file
-		cleanup = forwritelock $ preventWrite file
+		 - exclusive lock. -}
 		forwritelock a = 
 			when writelock $ whenM (doesFileExist file) $ a
+		prep = forwritelock $ allowWrite file
+		cleanup = forwritelock $ preventWrite file
 
 {- Calculates the relative path to use to link a file to a key. -}
 calcGitLink :: FilePath -> Key -> Annex FilePath