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-rw-r--r--app/Store.hs103
1 files changed, 46 insertions, 57 deletions
diff --git a/app/Store.hs b/app/Store.hs
index 91184a3..9e0ef00 100644
--- a/app/Store.hs
+++ b/app/Store.hs
@@ -1,4 +1,3 @@
-{-# LANGUAGE CPP #-}
{-# LANGUAGE OverloadedStrings #-}
{-# LANGUAGE TypeApplications #-}
{-# LANGUAGE TypeFamilyDependencies #-}
@@ -16,47 +15,40 @@
module Store where
-import Control.DeepSeq (NFData)
-import Control.Monad.IO.Class (liftIO)
-import qualified Control.Monad.State.Strict as S
-import qualified Data.ByteString as BS
-import qualified Data.ByteString.Short as BSS
-import qualified Data.Map.Strict as M
-import Data.Serialize (
- Serialize,
- decode,
- encode,
-#if MIN_VERSION_cereal(0,5,8)
-#else
- get, put
-#endif
- )
-import GHC.Generics (Generic)
-import Prelude hiding (lookup)
-import System.Directory (doesFileExist)
-import System.FilePath ((</>))
-import System.IO (Handle, IOMode(..), hTell, withFile)
-import System.IO.MMap (mmapFileByteString)
+import Control.DeepSeq ( NFData )
+import Control.Monad.IO.Class ( liftIO )
+import qualified Control.Monad.State.Strict as S
+import qualified Data.ByteString as BS
+import qualified Data.ByteString.Short as BSS
+import qualified Data.Map.Strict as M
+import Data.Serialize ( Serialize
+ , decode
+ , encode
+ )
+import GHC.Generics ( Generic )
+import Prelude hiding ( lookup )
+import System.Directory ( doesFileExist )
+import System.FilePath ( (</>) )
+import System.IO ( Handle
+ , IOMode(..)
+ , hTell
+ , withFile
+ )
+import System.IO.MMap ( mmapFileByteString )
data Store = Store
- { index :: M.Map BSS.ShortByteString Location
+ { index :: M.Map BSS.ShortByteString Location
, values :: BS.ByteString
}
data Location = Location
{ offset :: Int
, length :: Int
- } deriving (Show, Eq, Ord, Generic, NFData)
+ }
+ deriving (Show, Eq, Ord, Generic, NFData)
instance Serialize Location
-#if MIN_VERSION_cereal(0,5,8)
-#else
-instance Serialize BSS.ShortByteString where
- put = put . BSS.fromShort
- get = BSS.toShort <$> get
-#endif
-
class StoreItem item where
toByteString :: item -> BS.ByteString
fromByteString :: BS.ByteString -> Either String item
@@ -77,58 +69,55 @@ data ReadMode
load :: FilePath -> ReadMode -> IO (Either String Store)
load directoryPath readMode = do
let valuesFilePath = directoryPath </> valuesFileName
- indexFilePath = directoryPath </> indexFileName
+ indexFilePath = directoryPath </> indexFileName
(valuesFileExists, indexFileExists) <-
(,) <$> doesFileExist indexFilePath <*> doesFileExist valuesFilePath
case (valuesFileExists, indexFileExists) of
(True, True) -> do
- indexFile <- BS.readFile indexFilePath
- valuesFile <-
- case readMode of
- ReadEntireFile -> BS.readFile valuesFilePath
- MemoryMapFile -> mmapFileByteString valuesFilePath Nothing
+ indexFile <- BS.readFile indexFilePath
+ valuesFile <- case readMode of
+ ReadEntireFile -> BS.readFile valuesFilePath
+ MemoryMapFile -> mmapFileByteString valuesFilePath Nothing
let eitherIndex = decode @(M.Map BSS.ShortByteString Location) indexFile
case eitherIndex of
- Right locMap -> return . Right $ Store {index = locMap, values = valuesFile}
+ Right locMap ->
+ return . Right $ Store { index = locMap, values = valuesFile }
Left err -> return . Left $ "Error while decoding index : " ++ err
(False, False) ->
return . Left $ "Cannot find index and values in " ++ directoryPath
- (True, False) -> return . Left $ "Cannot find index in " ++ directoryPath
- (False, True) -> return . Left $ "Cannot find values in " ++ directoryPath
+ (True , False) -> return . Left $ "Cannot find index in " ++ directoryPath
+ (False, True ) -> return . Left $ "Cannot find values in " ++ directoryPath
lookup :: (StoreItem item) => KeyArgs item -> Store -> Either String item
lookup keyArgs = lookupByteString (itemKey keyArgs)
-lookupByteString ::
- (StoreItem item) => BSS.ShortByteString -> Store -> Either String item
-lookupByteString key store =
- case M.lookup key (index store) of
- Just (Location off len) ->
- fromByteString . BS.take len . BS.drop off $ values store
- Nothing -> Left $ "Cannot find item with key " ++ show key
+lookupByteString
+ :: (StoreItem item) => BSS.ShortByteString -> Store -> Either String item
+lookupByteString key store = case M.lookup key (index store) of
+ Just (Location off len) ->
+ fromByteString . BS.take len . BS.drop off $ values store
+ Nothing -> Left $ "Cannot find item with key " ++ show key
-data State =
- State (M.Map BSS.ShortByteString Location)
- Handle
+data State = State (M.Map BSS.ShortByteString Location) Handle
add :: (StoreItem item) => item -> KeyArgs item -> S.StateT State IO ()
add item keyArgs = do
- let bs = toByteString item
+ let bs = toByteString item
len = BS.length bs
State locMap handle <- S.get
- off <- liftIO $ fromIntegral <$> hTell handle
- _ <- liftIO $ BS.hPut handle bs
+ off <- liftIO $ fromIntegral <$> hTell handle
+ _ <- liftIO $ BS.hPut handle bs
S.put $ State (M.insert (itemKey keyArgs) (Location off len) locMap) handle
-createStore ::
- FilePath -> (Handle -> IO (M.Map BSS.ShortByteString Location)) -> IO ()
+createStore
+ :: FilePath -> (Handle -> IO (M.Map BSS.ShortByteString Location)) -> IO ()
createStore directoryPath action =
withFile (directoryPath </> valuesFileName) WriteMode $ \valuesHandle -> do
locMap <- action valuesHandle
BS.writeFile (directoryPath </> indexFileName) (encode locMap)
-writeValues ::
- Handle
+writeValues
+ :: Handle
-> M.Map BSS.ShortByteString Location
-> S.StateT State IO ()
-> IO (M.Map BSS.ShortByteString Location)