diff options
Diffstat (limited to 'src/Hakyll/Core/Store.hs')
| -rw-r--r-- | src/Hakyll/Core/Store.hs | 18 |
1 files changed, 14 insertions, 4 deletions
diff --git a/src/Hakyll/Core/Store.hs b/src/Hakyll/Core/Store.hs index e0d6774..7114afc 100644 --- a/src/Hakyll/Core/Store.hs +++ b/src/Hakyll/Core/Store.hs @@ -3,6 +3,7 @@ {-# LANGUAGE ExistentialQuantification #-} module Hakyll.Core.Store ( Store + , StoreGet (..) , makeStore , storeSet , storeGet @@ -25,6 +26,13 @@ import Hakyll.Core.Util.File -- data Storable = forall a. (Binary a, Typeable a) => Storable a +-- | Result when an item from the store +-- +data StoreGet a = Found a + | NotFound + | WrongType + deriving (Show, Eq, Ord) + -- | Data structure used for the store -- data Store = Store @@ -72,22 +80,24 @@ storeSet store name identifier value = do -- | Load an item -- storeGet :: (Binary a, Typeable a) - => Store -> String -> Identifier -> IO (Maybe a) + => Store -> String -> Identifier -> IO (StoreGet a) storeGet store name identifier = do -- First check the in-memory map map' <- readMVar $ storeMap store case M.lookup path map' of -- Found in the in-memory map - Just (Storable s) -> return $ cast s + Just (Storable s) -> return $ case cast s of + Nothing -> WrongType + Just s' -> Found s' -- Not found in the map, try the filesystem Nothing -> do exists <- doesFileExist path if not exists -- Not found in the filesystem either - then return Nothing + then return NotFound -- Found in the filesystem else do v <- decodeFile path addToMap store path v - return $ Just v + return $ Found v where path = makePath store name identifier |