diff options
Diffstat (limited to 'src/Erebos/Storage')
| -rw-r--r-- | src/Erebos/Storage/Backend.hs | 28 | ||||
| -rw-r--r-- | src/Erebos/Storage/Disk.hs | 230 | ||||
| -rw-r--r-- | src/Erebos/Storage/Head.hs | 259 | ||||
| -rw-r--r-- | src/Erebos/Storage/Internal.hs | 242 | ||||
| -rw-r--r-- | src/Erebos/Storage/Key.hs | 74 | ||||
| -rw-r--r-- | src/Erebos/Storage/Memory.hs | 101 | ||||
| -rw-r--r-- | src/Erebos/Storage/Merge.hs | 3 |
7 files changed, 768 insertions, 169 deletions
diff --git a/src/Erebos/Storage/Backend.hs b/src/Erebos/Storage/Backend.hs new file mode 100644 index 0000000..620d423 --- /dev/null +++ b/src/Erebos/Storage/Backend.hs @@ -0,0 +1,28 @@ +{-| +Description: Implement custom storage backend + +Exports type class, which can be used to create custom 'Storage' backend. +-} + +module Erebos.Storage.Backend ( + StorageBackend(..), + Complete, Partial, + Storage, PartialStorage, + newStorage, + + WatchID, startWatchID, nextWatchID, +) where + +import Control.Concurrent.MVar + +import Data.HashTable.IO qualified as HT + +import Erebos.Object.Internal +import Erebos.Storage.Internal + + +newStorage :: StorageBackend bck => bck -> IO (Storage' (BackendCompleteness bck)) +newStorage stBackend = do + stRefGeneration <- newMVar =<< HT.new + stRefRoots <- newMVar =<< HT.new + return Storage {..} diff --git a/src/Erebos/Storage/Disk.hs b/src/Erebos/Storage/Disk.hs new file mode 100644 index 0000000..01821f7 --- /dev/null +++ b/src/Erebos/Storage/Disk.hs @@ -0,0 +1,230 @@ +module Erebos.Storage.Disk ( + openStorage, +) where + +import Codec.Compression.Zlib + +import Control.Arrow +import Control.Concurrent +import Control.Exception +import Control.Monad + +import Data.ByteArray qualified as BA +import Data.ByteString (ByteString) +import Data.ByteString qualified as B +import Data.ByteString.Char8 qualified as BC +import Data.ByteString.Lazy qualified as BL +import Data.ByteString.Lazy.Char8 qualified as BLC +import Data.Function +import Data.List +import Data.Maybe +import Data.UUID qualified as U + +import System.Directory +import System.FSNotify +import System.FilePath +import System.IO +import System.IO.Error + +import Erebos.Object +import Erebos.Storage.Backend +import Erebos.Storage.Head +import Erebos.Storage.Internal +import Erebos.Storage.Platform + + +data DiskStorage = StorageDir + { dirPath :: FilePath + , dirWatchers :: MVar ( Maybe WatchManager, [ HeadTypeID ], WatchList ) + } + +instance Eq DiskStorage where + (==) = (==) `on` dirPath + +instance Show DiskStorage where + show StorageDir { dirPath = path } = "dir:" ++ path + +instance StorageBackend DiskStorage where + backendLoadBytes StorageDir {..} dgst = + handleJust (guard . isDoesNotExistError) (const $ return Nothing) $ + Just . decompress . BL.fromChunks . (:[]) <$> (B.readFile $ refPath dirPath dgst) + backendStoreBytes StorageDir {..} dgst = writeFileOnce (refPath dirPath dgst) . compress + + + backendLoadHeads StorageDir {..} tid = do + let hpath = headTypePath dirPath tid + + files <- filterM (doesFileExist . (hpath </>)) =<< + handleJust (\e -> guard (isDoesNotExistError e)) (const $ return []) + (getDirectoryContents hpath) + fmap catMaybes $ forM files $ \hname -> do + case U.fromString hname of + Just hid -> do + content <- B.readFile (hpath </> hname) + return $ do + (h : _) <- Just (BC.lines content) + dgst <- readRefDigest h + Just $ ( HeadID hid, dgst ) + Nothing -> return Nothing + + backendLoadHead StorageDir {..} tid hid = do + handleJust (guard . isDoesNotExistError) (const $ return Nothing) $ do + (h:_) <- BC.lines <$> B.readFile (headPath dirPath tid hid) + return $ readRefDigest h + + backendStoreHead StorageDir {..} tid hid dgst = do + Right () <- writeFileChecked (headPath dirPath tid hid) Nothing $ + showRefDigest dgst `B.append` BC.singleton '\n' + return () + + backendReplaceHead StorageDir {..} tid hid expected new = do + let filename = headPath dirPath tid hid + showDgstL r = showRefDigest r `B.append` BC.singleton '\n' + + writeFileChecked filename (Just $ showDgstL expected) (showDgstL new) >>= \case + Left Nothing -> return $ Left Nothing + Left (Just bs) -> do Just cur <- return $ readRefDigest $ BC.takeWhile (/='\n') bs + return $ Left $ Just cur + Right () -> return $ Right new + + backendWatchHead st@StorageDir {..} tid hid cb = do + modifyMVar dirWatchers $ \( mbmanager, ilist, wl ) -> do + manager <- maybe startManager return mbmanager + ilist' <- case tid `elem` ilist of + True -> return ilist + False -> do + void $ watchDir manager (headTypePath dirPath tid) (const True) $ \case + Added { eventPath = fpath } | Just ihid <- HeadID <$> U.fromString (takeFileName fpath) -> do + backendLoadHead st tid ihid >>= \case + Just dgst -> do + (_, _, iwl) <- readMVar dirWatchers + mapM_ ($ dgst) . map wlFun . filter ((== (tid, ihid)) . wlHead) . wlList $ iwl + Nothing -> return () + _ -> return () + return $ tid : ilist + return $ first ( Just manager, ilist', ) $ watchListAdd tid hid cb wl + + backendUnwatchHead StorageDir {..} wid = do + modifyMVar_ dirWatchers $ \( mbmanager, ilist, wl ) -> do + return ( mbmanager, ilist, watchListDel wid wl ) + + + backendListKeys StorageDir {..} = do + catMaybes . map (readRefDigest . BC.pack) <$> + listDirectory (keyDirPath dirPath) + + backendLoadKey StorageDir {..} dgst = do + tryIOError (BC.readFile (keyFilePath dirPath dgst)) >>= \case + Right kdata -> return $ Just $ BA.convert kdata + Left _ -> return Nothing + + backendStoreKey StorageDir {..} dgst key = do + writeFileOnce (keyFilePath dirPath dgst) (BL.fromStrict $ BA.convert key) + + backendRemoveKey StorageDir {..} dgst = do + void $ tryIOError (removeFile $ keyFilePath dirPath dgst) + + +storageVersion :: String +storageVersion = "0.1" + +openStorage :: FilePath -> IO Storage +openStorage path = modifyIOError annotate $ do + let versionFileName = "erebos-storage" + let versionPath = path </> versionFileName + let writeVersionFile = writeFileOnce versionPath $ BLC.pack $ storageVersion <> "\n" + + maybeVersion <- handleJust (guard . isDoesNotExistError) (const $ return Nothing) $ + Just <$> readFile versionPath + version <- case maybeVersion of + Just versionContent -> do + return $ takeWhile (/= '\n') versionContent + + Nothing -> do + files <- handleJust (guard . isDoesNotExistError) (const $ return []) $ + listDirectory path + when (not $ or + [ null files + , versionFileName `elem` files + , (versionFileName ++ ".lock") `elem` files + , "objects" `elem` files && "heads" `elem` files + ]) $ do + fail "directory is neither empty, nor an existing erebos storage" + + createDirectoryIfMissing True $ path + writeVersionFile + takeWhile (/= '\n') <$> readFile versionPath + + when (version /= storageVersion) $ do + fail $ "unsupported storage version " <> version + + createDirectoryIfMissing True $ path </> "objects" + createDirectoryIfMissing True $ path </> "heads" + watchers <- newMVar ( Nothing, [], WatchList startWatchID [] ) + newStorage $ StorageDir path watchers + where + annotate e = annotateIOError e "failed to open storage" Nothing (Just path) + + +refPath :: FilePath -> RefDigest -> FilePath +refPath spath rdgst = intercalate "/" [ spath, "objects", BC.unpack alg, pref, rest ] + where (alg, dgst) = showRefDigestParts rdgst + (pref, rest) = splitAt 2 $ BC.unpack dgst + +headTypePath :: FilePath -> HeadTypeID -> FilePath +headTypePath spath (HeadTypeID tid) = spath </> "heads" </> U.toString tid + +headPath :: FilePath -> HeadTypeID -> HeadID -> FilePath +headPath spath tid (HeadID hid) = headTypePath spath tid </> U.toString hid + +keyDirPath :: FilePath -> FilePath +keyDirPath sdir = sdir </> "keys" + +keyFilePath :: FilePath -> RefDigest -> FilePath +keyFilePath sdir dgst = keyDirPath sdir </> (BC.unpack $ showRefDigest dgst) + + +openLockFile :: FilePath -> IO Handle +openLockFile path = do + createDirectoryIfMissing True (takeDirectory path) + retry 10 $ createFileExclusive path + where + retry :: Int -> IO a -> IO a + retry 0 act = act + retry n act = catchJust (\e -> if isAlreadyExistsError e then Just () else Nothing) + act (\_ -> threadDelay (100 * 1000) >> retry (n - 1) act) + +writeFileOnce :: FilePath -> BL.ByteString -> IO () +writeFileOnce file content = bracket (openLockFile locked) + hClose $ \h -> do + doesFileExist file >>= \case + True -> removeFile locked + False -> do BL.hPut h content + hClose h + renameFile locked file + where locked = file ++ ".lock" + +writeFileChecked :: FilePath -> Maybe ByteString -> ByteString -> IO (Either (Maybe ByteString) ()) +writeFileChecked file prev content = bracket (openLockFile locked) + hClose $ \h -> do + (prev,) <$> doesFileExist file >>= \case + (Nothing, True) -> do + current <- B.readFile file + removeFile locked + return $ Left $ Just current + (Nothing, False) -> do B.hPut h content + hClose h + renameFile locked file + return $ Right () + (Just expected, True) -> do + current <- B.readFile file + if current == expected then do B.hPut h content + hClose h + renameFile locked file + return $ return () + else do removeFile locked + return $ Left $ Just current + (Just _, False) -> do + removeFile locked + return $ Left Nothing + where locked = file ++ ".lock" diff --git a/src/Erebos/Storage/Head.hs b/src/Erebos/Storage/Head.hs new file mode 100644 index 0000000..8f8e009 --- /dev/null +++ b/src/Erebos/Storage/Head.hs @@ -0,0 +1,259 @@ +{-| +Description: Define, use and watch heads + +Provides data types and functions for reading, writing or watching `Head's. +Type class `HeadType' is used to define custom new `Head' types. +-} + +module Erebos.Storage.Head ( + -- * Head type and accessors + Head, HeadType(..), + HeadID, HeadTypeID, mkHeadTypeID, + headId, headStorage, headRef, headObject, headStoredObject, + + -- * Loading and storing heads + loadHeads, loadHead, reloadHead, + storeHead, replaceHead, updateHead, updateHead_, + loadHeadRaw, storeHeadRaw, replaceHeadRaw, + + -- * Watching heads + WatchedHead, + watchHead, watchHeadWith, unwatchHead, + watchHeadRaw, +) where + +import Control.Concurrent +import Control.Monad +import Control.Monad.Reader + +import Data.Bifunctor +import Data.Typeable +import Data.UUID qualified as U +import Data.UUID.V4 qualified as U + +import Erebos.Object +import Erebos.Storable +import Erebos.Storage.Backend +import Erebos.Storage.Internal + + +-- | Represents loaded Erebos storage head, along with the object it pointed to +-- at the time it was loaded. +-- +-- Each possible head type has associated unique ID, represented as +-- `HeadTypeID'. For each type, there can be multiple individual heads in given +-- storage, each also identified by unique ID (`HeadID'). +data Head a = Head HeadID (Stored a) + deriving (Eq, Show) + +-- | Instances of this class can be used as objects pointed to by heads in +-- Erebos storage. Each such type must be `Storable' and have a unique ID. +-- +-- To create a custom head type, generate a new UUID and assign it to the type using +-- `mkHeadTypeID': +-- +-- > instance HeadType MyType where +-- > headTypeID _ = mkHeadTypeID "86e8033d-c476-4f81-9b7c-fd36b9144475" +class Storable a => HeadType a where + headTypeID :: proxy a -> HeadTypeID + -- ^ Get the ID of the given head type; must be unique for each `HeadType' instance. + +instance MonadIO m => MonadStorage (ReaderT (Head a) m) where + getStorage = asks $ headStorage + + +-- | Get `HeadID' associated with given `Head'. +headId :: Head a -> HeadID +headId (Head uuid _) = uuid + +-- | Get storage from which the `Head' was loaded. +headStorage :: Head a -> Storage +headStorage = refStorage . headRef + +-- | Get `Ref' of the `Head'\'s associated object. +headRef :: Head a -> Ref +headRef (Head _ sx) = storedRef sx + +-- | Get the object the `Head' pointed to when it was loaded. +headObject :: Head a -> a +headObject (Head _ sx) = fromStored sx + +-- | Get the object the `Head' pointed to when it was loaded as a `Stored' value. +headStoredObject :: Head a -> Stored a +headStoredObject (Head _ sx) = sx + +-- | Create `HeadTypeID' from string representation of UUID. +mkHeadTypeID :: String -> HeadTypeID +mkHeadTypeID = maybe (error "Invalid head type ID") HeadTypeID . U.fromString + + +-- | Load all `Head's of type @a@ from storage. +loadHeads :: forall a m. MonadIO m => HeadType a => Storage -> m [Head a] +loadHeads st@Storage {..} = + map (uncurry Head . fmap (wrappedLoad . Ref st)) + <$> liftIO (backendLoadHeads stBackend (headTypeID @a Proxy)) + +-- | Try to load a `Head' of type @a@ from storage. +loadHead + :: forall a m. (HeadType a, MonadIO m) + => Storage -- ^ Storage from which to load the head + -> HeadID -- ^ ID of the particular head + -> m (Maybe (Head a)) -- ^ Head object, or `Nothing' if not found +loadHead st hid = fmap (Head hid . wrappedLoad) <$> loadHeadRaw st (headTypeID @a Proxy) hid + +-- | Try to load `Head' using a raw head and type IDs, getting `Ref' if found. +loadHeadRaw + :: forall m. MonadIO m + => Storage -- ^ Storage from which to load the head + -> HeadTypeID -- ^ ID of the head type + -> HeadID -- ^ ID of the particular head + -> m (Maybe Ref) -- ^ `Ref' pointing to the head object, or `Nothing' if not found +loadHeadRaw st@Storage {..} tid hid = do + fmap (Ref st) <$> liftIO (backendLoadHead stBackend tid hid) + +-- | Reload the given head from storage, returning `Head' with updated object, +-- or `Nothing' if there is no longer head with the particular ID in storage. +reloadHead :: (HeadType a, MonadIO m) => Head a -> m (Maybe (Head a)) +reloadHead (Head hid (Stored (Ref st _) _)) = loadHead st hid + +-- | Store a new `Head' of type 'a' in the storage. +storeHead :: forall a m. MonadIO m => HeadType a => Storage -> a -> m (Head a) +storeHead st obj = do + let tid = headTypeID @a Proxy + stored <- wrappedStore st obj + hid <- storeHeadRaw st tid (storedRef stored) + return $ Head hid stored + +-- | Store a new `Head' in the storage, using the raw `HeadTypeID' and `Ref', +-- the function returns the assigned `HeadID' of the new head. +storeHeadRaw :: forall m. MonadIO m => Storage -> HeadTypeID -> Ref -> m HeadID +storeHeadRaw Storage {..} tid ref = liftIO $ do + hid <- HeadID <$> U.nextRandom + backendStoreHead stBackend tid hid (refDigest ref) + return hid + +-- | Try to replace existing `Head' of type @a@ in the storage. Function fails +-- if the head value in storage changed after being loaded here; for automatic +-- retry see `updateHead'. +replaceHead + :: forall a m. (HeadType a, MonadIO m) + => Head a -- ^ Existing head, associated object is supposed to match the one in storage + -> Stored a -- ^ Intended new value + -> m (Either (Maybe (Head a)) (Head a)) + -- ^ + -- [@`Left' `Nothing'@]: + -- Nothing was stored – the head no longer exists in storage. + -- [@`Left' (`Just' h)@]: + -- Nothing was stored – the head value in storage does not match + -- the first parameter, but is @h@ instead. + -- [@`Right' h@]: + -- Head value was updated in storage, the new head is @h@ (which is + -- the same as first parameter with associated object replaced by + -- the second parameter). +replaceHead prev@(Head hid pobj) stored' = liftIO $ do + let st = headStorage prev + tid = headTypeID @a Proxy + stored <- copyStored st stored' + bimap (fmap $ Head hid . wrappedLoad) (const $ Head hid stored) <$> + replaceHeadRaw st tid hid (storedRef pobj) (storedRef stored) + +-- | Try to replace existing head using raw IDs and `Ref's. +replaceHeadRaw + :: forall m. MonadIO m + => Storage -- ^ Storage to use + -> HeadTypeID -- ^ ID of the head type + -> HeadID -- ^ ID of the particular head + -> Ref -- ^ Expected value in storage + -> Ref -- ^ Intended new value + -> m (Either (Maybe Ref) Ref) + -- ^ + -- [@`Left' `Nothing'@]: + -- Nothing was stored – the head no longer exists in storage. + -- [@`Left' (`Just' r)@]: + -- Nothing was stored – the head value in storage does not match + -- the expected value, but is @r@ instead. + -- [@`Right' r@]: + -- Head value was updated in storage, the new head value is @r@ + -- (which is the same as the indended value). +replaceHeadRaw st@Storage {..} tid hid prev new = liftIO $ do + _ <- copyRef st new + bimap (fmap $ Ref st) (Ref st) <$> backendReplaceHead stBackend tid hid (refDigest prev) (refDigest new) + +-- | Update existing existing `Head' of type @a@ in the storage, using a given +-- function. The update function may be called multiple times in case the head +-- content changes concurrently during evaluation. +updateHead + :: (HeadType a, MonadIO m) + => Head a -- ^ Existing head to be updated + -> (Stored a -> m ( Stored a, b )) + -- ^ Function that gets current value of the head and returns updated + -- value, along with a custom extra value to be returned from + -- `updateHead' call. The function may be called multiple times. + -> m ( Maybe (Head a), b ) + -- ^ First element contains either the new head as @`Just' h@, or + -- `Nothing' in case the head no longer exists in storage. Second + -- element is the value from last call to the update function. +updateHead h f = do + (o, x) <- f $ headStoredObject h + replaceHead h o >>= \case + Right h' -> return (Just h', x) + Left Nothing -> return (Nothing, x) + Left (Just h') -> updateHead h' f + +-- | Update existing existing `Head' of type @a@ in the storage, using a given +-- function. The update function may be called multiple times in case the head +-- content changes concurrently during evaluation. +updateHead_ + :: (HeadType a, MonadIO m) + => Head a -- ^ Existing head to be updated + -> (Stored a -> m (Stored a)) + -- ^ Function that gets current value of the head and returns updated + -- value; may be called multiple times. + -> m (Maybe (Head a)) + -- ^ The new head as @`Just' h@, or `Nothing' in case the head no + -- longer exists in storage. +updateHead_ h = fmap fst . updateHead h . (fmap (,()) .) + + +-- | Represents a handle of a watched head, which can be used to cancel the +-- watching. +data WatchedHead = forall a. WatchedHead Storage WatchID (MVar a) + +-- | Watch the given head. The callback will be called with the current head +-- value, and then again each time the head changes. +watchHead :: forall a. HeadType a => Head a -> (Head a -> IO ()) -> IO WatchedHead +watchHead h = watchHeadWith h id + +-- | Watch the given head using custom selector function. The callback will be +-- called with the value derived from current head state, and then again each +-- time the selected value changes according to its `Eq' instance. +watchHeadWith + :: forall a b. (HeadType a, Eq b) + => Head a -- ^ Head to watch + -> (Head a -> b) -- ^ Selector function + -> (b -> IO ()) -- ^ Callback + -> IO WatchedHead -- ^ Watched head handle +watchHeadWith (Head hid (Stored (Ref st _) _)) sel cb = do + watchHeadRaw st (headTypeID @a Proxy) hid (sel . Head hid . wrappedLoad) cb + +-- | Watch the given head using raw IDs and a selector from `Ref'. +watchHeadRaw :: forall b. Eq b => Storage -> HeadTypeID -> HeadID -> (Ref -> b) -> (b -> IO ()) -> IO WatchedHead +watchHeadRaw st@Storage {..} tid hid sel cb = do + memo <- newEmptyMVar + let cb' dgst = do + let x = sel (Ref st dgst) + modifyMVar_ memo $ \prev -> do + when (Just x /= prev) $ cb x + return $ Just x + wid <- backendWatchHead stBackend tid hid cb' + + cur <- fmap sel <$> loadHeadRaw st tid hid + maybe (return ()) cb cur + putMVar memo cur + + return $ WatchedHead st wid memo + +-- | Stop watching previously watched head. +unwatchHead :: WatchedHead -> IO () +unwatchHead (WatchedHead Storage {..} wid _) = do + backendUnwatchHead stBackend wid diff --git a/src/Erebos/Storage/Internal.hs b/src/Erebos/Storage/Internal.hs index 8b794d8..6df1410 100644 --- a/src/Erebos/Storage/Internal.hs +++ b/src/Erebos/Storage/Internal.hs @@ -1,7 +1,5 @@ module Erebos.Storage.Internal where -import Codec.Compression.Zlib - import Control.Arrow import Control.Concurrent import Control.DeepSeq @@ -13,76 +11,145 @@ import Crypto.Hash import Data.Bits import Data.ByteArray (ByteArray, ByteArrayAccess, ScrubbedBytes) -import qualified Data.ByteArray as BA +import Data.ByteArray qualified as BA import Data.ByteString (ByteString) -import qualified Data.ByteString as B -import qualified Data.ByteString.Char8 as BC -import qualified Data.ByteString.Lazy as BL +import Data.ByteString qualified as B +import Data.ByteString.Char8 qualified as BC +import Data.ByteString.Lazy qualified as BL import Data.Char -import Data.Function +import Data.HashTable.IO qualified as HT import Data.Hashable -import qualified Data.HashTable.IO as HT import Data.Kind -import Data.List -import Data.Map (Map) -import qualified Data.Map as M +import Data.Typeable import Data.UUID (UUID) import Foreign.Storable (peek) -import System.Directory -import System.FSNotify (WatchManager) -import System.FilePath -import System.IO -import System.IO.Error import System.IO.Unsafe (unsafePerformIO) -import Erebos.Storage.Platform - -data Storage' c = Storage - { stBacking :: StorageBacking c - , stParent :: Maybe (Storage' Identity) +data Storage' c = forall bck. (StorageBackend bck, BackendCompleteness bck ~ c) => Storage + { stBackend :: bck , stRefGeneration :: MVar (HT.BasicHashTable RefDigest Generation) , stRefRoots :: MVar (HT.BasicHashTable RefDigest [RefDigest]) } +type Storage = Storage' Complete +type PartialStorage = Storage' Partial + instance Eq (Storage' c) where - (==) = (==) `on` (stBacking &&& stParent) + Storage { stBackend = b } == Storage { stBackend = b' } + | Just b'' <- cast b' = b == b'' + | otherwise = False instance Show (Storage' c) where - show st@(Storage { stBacking = StorageDir { dirPath = path }}) = "dir" ++ showParentStorage st ++ ":" ++ path - show st@(Storage { stBacking = StorageMemory {} }) = "mem" ++ showParentStorage st - -showParentStorage :: Storage' c -> String -showParentStorage Storage { stParent = Nothing } = "" -showParentStorage Storage { stParent = Just st } = "@" ++ show st - -data StorageBacking c - = StorageDir { dirPath :: FilePath - , dirWatchers :: MVar ( Maybe WatchManager, [ HeadTypeID ], WatchList c ) - } - | StorageMemory { memHeads :: MVar [((HeadTypeID, HeadID), Ref' c)] - , memObjs :: MVar (Map RefDigest BL.ByteString) - , memKeys :: MVar (Map RefDigest ScrubbedBytes) - , memWatchers :: MVar (WatchList c) - } - deriving (Eq) + show Storage { stBackend = b } = show b ++ showParentStorage b + +showParentStorage :: StorageBackend bck => bck -> String +showParentStorage bck + | Just (st :: Storage) <- cast (backendParent bck) = "@" ++ show st + | Just (st :: PartialStorage) <- cast (backendParent bck) = "@" ++ show st + | otherwise = "" + + +class (Eq bck, Show bck, Typeable bck, Typeable (BackendParent bck)) => StorageBackend bck where + type BackendCompleteness bck :: Type -> Type + type BackendCompleteness bck = Complete + + type BackendParent bck :: Type + type BackendParent bck = () + backendParent :: bck -> BackendParent bck + default backendParent :: BackendParent bck ~ () => bck -> BackendParent bck + backendParent _ = () + + + backendLoadBytes :: bck -> RefDigest -> IO (Maybe BL.ByteString) + default backendLoadBytes :: BackendParent bck ~ Storage => bck -> RefDigest -> IO (Maybe BL.ByteString) + backendLoadBytes bck = case backendParent bck of Storage { stBackend = bck' } -> backendLoadBytes bck' + + backendStoreBytes :: bck -> RefDigest -> BL.ByteString -> IO () + default backendStoreBytes :: BackendParent bck ~ Storage => bck -> RefDigest -> BL.ByteString -> IO () + backendStoreBytes bck = case backendParent bck of Storage { stBackend = bck' } -> backendStoreBytes bck' + + + backendLoadHeads :: bck -> HeadTypeID -> IO [ ( HeadID, RefDigest ) ] + default backendLoadHeads :: BackendParent bck ~ Storage => bck -> HeadTypeID -> IO [ ( HeadID, RefDigest ) ] + backendLoadHeads bck = case backendParent bck of Storage { stBackend = bck' } -> backendLoadHeads bck' + + backendLoadHead :: bck -> HeadTypeID -> HeadID -> IO (Maybe RefDigest) + default backendLoadHead :: BackendParent bck ~ Storage => bck -> HeadTypeID -> HeadID -> IO (Maybe RefDigest) + backendLoadHead bck = case backendParent bck of Storage { stBackend = bck' } -> backendLoadHead bck' + + backendStoreHead :: bck -> HeadTypeID -> HeadID -> RefDigest -> IO () + default backendStoreHead :: BackendParent bck ~ Storage => bck -> HeadTypeID -> HeadID -> RefDigest -> IO () + backendStoreHead bck = case backendParent bck of Storage { stBackend = bck' } -> backendStoreHead bck' + + backendReplaceHead :: bck -> HeadTypeID -> HeadID -> RefDigest -> RefDigest -> IO (Either (Maybe RefDigest) RefDigest) + default backendReplaceHead :: BackendParent bck ~ Storage => bck -> HeadTypeID -> HeadID -> RefDigest -> RefDigest -> IO (Either (Maybe RefDigest) RefDigest) + backendReplaceHead bck = case backendParent bck of Storage { stBackend = bck' } -> backendReplaceHead bck' + + backendWatchHead :: bck -> HeadTypeID -> HeadID -> (RefDigest -> IO ()) -> IO WatchID + default backendWatchHead :: BackendParent bck ~ Storage => bck -> HeadTypeID -> HeadID -> (RefDigest -> IO ()) -> IO WatchID + backendWatchHead bck = case backendParent bck of Storage { stBackend = bck' } -> backendWatchHead bck' + + backendUnwatchHead :: bck -> WatchID -> IO () + default backendUnwatchHead :: BackendParent bck ~ Storage => bck -> WatchID -> IO () + backendUnwatchHead bck = case backendParent bck of Storage { stBackend = bck' } -> backendUnwatchHead bck' + + + backendListKeys :: bck -> IO [ RefDigest ] + default backendListKeys :: BackendParent bck ~ Storage => bck -> IO [ RefDigest ] + backendListKeys bck = case backendParent bck of Storage { stBackend = bck' } -> backendListKeys bck' + + backendLoadKey :: bck -> RefDigest -> IO (Maybe ScrubbedBytes) + default backendLoadKey :: BackendParent bck ~ Storage => bck -> RefDigest -> IO (Maybe ScrubbedBytes) + backendLoadKey bck = case backendParent bck of Storage { stBackend = bck' } -> backendLoadKey bck' + + backendStoreKey :: bck -> RefDigest -> ScrubbedBytes -> IO () + default backendStoreKey :: BackendParent bck ~ Storage => bck -> RefDigest -> ScrubbedBytes -> IO () + backendStoreKey bck = case backendParent bck of Storage { stBackend = bck' } -> backendStoreKey bck' + + backendRemoveKey :: bck -> RefDigest -> IO () + default backendRemoveKey :: BackendParent bck ~ Storage => bck -> RefDigest -> IO () + backendRemoveKey bck = case backendParent bck of Storage { stBackend = bck' } -> backendRemoveKey bck' + + newtype WatchID = WatchID Int - deriving (Eq, Ord, Num) + deriving (Eq, Ord) + +startWatchID :: WatchID +startWatchID = WatchID 1 -data WatchList c = WatchList +nextWatchID :: WatchID -> WatchID +nextWatchID (WatchID n) = WatchID (n + 1) + +data WatchList = WatchList { wlNext :: WatchID - , wlList :: [WatchListItem c] + , wlList :: [ WatchListItem ] } -data WatchListItem c = WatchListItem +data WatchListItem = WatchListItem { wlID :: WatchID - , wlHead :: (HeadTypeID, HeadID) - , wlFun :: Ref' c -> IO () + , wlHead :: ( HeadTypeID, HeadID ) + , wlFun :: RefDigest -> IO () } +watchListAdd :: HeadTypeID -> HeadID -> (RefDigest -> IO ()) -> WatchList -> ( WatchList, WatchID ) +watchListAdd tid hid cb wl = ( wl', wlNext wl ) + where + wl' = wl + { wlNext = nextWatchID (wlNext wl) + , wlList = WatchListItem + { wlID = wlNext wl + , wlHead = (tid, hid) + , wlFun = cb + } : wlList wl + } + +watchListDel :: WatchID -> WatchList -> WatchList +watchListDel wid wl = wl { wlList = filter ((/= wid) . wlID) $ wlList wl } + newtype RefDigest = RefDigest (Digest Blake2b_256) deriving (Eq, Ord, NFData, ByteArrayAccess) @@ -92,6 +159,9 @@ instance Show RefDigest where data Ref' c = Ref (Storage' c) RefDigest +type Ref = Ref' Complete +type PartialRef = Ref' Partial + instance Eq (Ref' c) where Ref _ d1 == Ref _ d2 = d1 == d2 @@ -159,12 +229,11 @@ readHex = return . BA.concat <=< readHex' newtype Generation = Generation Int deriving (Eq, Show) -data Head' c a = Head HeadID (Stored' c a) - deriving (Eq, Show) - +-- | UUID of individual Erebos storage head. newtype HeadID = HeadID UUID deriving (Eq, Ord, Show) +-- | UUID of Erebos storage head type. newtype HeadTypeID = HeadTypeID UUID deriving (Eq, Ord) @@ -184,7 +253,7 @@ storedStorage (Stored (Ref st _) _) = st type Complete = Identity type Partial = Either RefDigest -class (Traversable compl, Monad compl) => StorageCompleteness compl where +class (Traversable compl, Monad compl, Typeable compl) => StorageCompleteness compl where type LoadResult compl a :: Type returnLoadResult :: compl a -> LoadResult compl a ioLoadBytes :: Ref' compl -> IO (compl BL.ByteString) @@ -201,71 +270,16 @@ instance StorageCompleteness Partial where ioLoadBytes (Ref st dgst) = maybe (Left dgst) Right <$> ioLoadBytesFromStorage st dgst unsafeStoreRawBytes :: Storage' c -> BL.ByteString -> IO (Ref' c) -unsafeStoreRawBytes st raw = do - let dgst = hashToRefDigest raw - case stBacking st of - StorageDir { dirPath = sdir } -> writeFileOnce (refPath sdir dgst) $ compress raw - StorageMemory { memObjs = tobjs } -> - dgst `deepseq` -- the TVar may be accessed when evaluating the data to be written - modifyMVar_ tobjs (return . M.insert dgst raw) +unsafeStoreRawBytes st@Storage {..} raw = do + dgst <- evaluate $ force $ hashToRefDigest raw + backendStoreBytes stBackend dgst raw return $ Ref st dgst ioLoadBytesFromStorage :: Storage' c -> RefDigest -> IO (Maybe BL.ByteString) -ioLoadBytesFromStorage st dgst = loadCurrent st >>= - \case Just bytes -> return $ Just bytes - Nothing | Just parent <- stParent st -> ioLoadBytesFromStorage parent dgst - | otherwise -> return Nothing - where loadCurrent Storage { stBacking = StorageDir { dirPath = spath } } = handleJust (guard . isDoesNotExistError) (const $ return Nothing) $ - Just . decompress . BL.fromChunks . (:[]) <$> (B.readFile $ refPath spath dgst) - loadCurrent Storage { stBacking = StorageMemory { memObjs = tobjs } } = M.lookup dgst <$> readMVar tobjs - -refPath :: FilePath -> RefDigest -> FilePath -refPath spath rdgst = intercalate "/" [spath, "objects", BC.unpack alg, pref, rest] - where (alg, dgst) = showRefDigestParts rdgst - (pref, rest) = splitAt 2 $ BC.unpack dgst - - -openLockFile :: FilePath -> IO Handle -openLockFile path = do - createDirectoryIfMissing True (takeDirectory path) - retry 10 $ createFileExclusive path - where - retry :: Int -> IO a -> IO a - retry 0 act = act - retry n act = catchJust (\e -> if isAlreadyExistsError e then Just () else Nothing) - act (\_ -> threadDelay (100 * 1000) >> retry (n - 1) act) - -writeFileOnce :: FilePath -> BL.ByteString -> IO () -writeFileOnce file content = bracket (openLockFile locked) - hClose $ \h -> do - doesFileExist file >>= \case - True -> removeFile locked - False -> do BL.hPut h content - hClose h - renameFile locked file - where locked = file ++ ".lock" - -writeFileChecked :: FilePath -> Maybe ByteString -> ByteString -> IO (Either (Maybe ByteString) ()) -writeFileChecked file prev content = bracket (openLockFile locked) - hClose $ \h -> do - (prev,) <$> doesFileExist file >>= \case - (Nothing, True) -> do - current <- B.readFile file - removeFile locked - return $ Left $ Just current - (Nothing, False) -> do B.hPut h content - hClose h - renameFile locked file - return $ Right () - (Just expected, True) -> do - current <- B.readFile file - if current == expected then do B.hPut h content - hClose h - renameFile locked file - return $ return () - else do removeFile locked - return $ Left $ Just current - (Just _, False) -> do - removeFile locked - return $ Left Nothing - where locked = file ++ ".lock" +ioLoadBytesFromStorage Storage {..} dgst = + backendLoadBytes stBackend dgst >>= \case + Just bytes -> return $ Just bytes + Nothing + | Just (parent :: Storage) <- cast (backendParent stBackend) -> ioLoadBytesFromStorage parent dgst + | Just (parent :: PartialStorage) <- cast (backendParent stBackend) -> ioLoadBytesFromStorage parent dgst + | otherwise -> return Nothing diff --git a/src/Erebos/Storage/Key.hs b/src/Erebos/Storage/Key.hs index 5da79e3..fab2103 100644 --- a/src/Erebos/Storage/Key.hs +++ b/src/Erebos/Storage/Key.hs @@ -4,21 +4,14 @@ module Erebos.Storage.Key ( moveKeys, ) where -import Control.Concurrent.MVar import Control.Monad import Control.Monad.Except import Control.Monad.IO.Class import Data.ByteArray -import qualified Data.ByteString.Char8 as BC -import qualified Data.ByteString.Lazy as BL -import qualified Data.Map as M +import Data.Typeable -import System.Directory -import System.FilePath -import System.IO.Error - -import Erebos.Storage +import Erebos.Storable import Erebos.Storage.Internal class Storable pub => KeyPair sec pub | sec -> pub, pub -> sec where @@ -28,59 +21,32 @@ class Storable pub => KeyPair sec pub | sec -> pub, pub -> sec where keyFromData :: ScrubbedBytes -> Stored pub -> Maybe sec -keyFilePath :: KeyPair sec pub => FilePath -> Stored pub -> FilePath -keyFilePath sdir pkey = sdir </> "keys" </> (BC.unpack $ showRef $ storedRef pkey) - storeKey :: KeyPair sec pub => sec -> IO () storeKey key = do let spub = keyGetPublic key - case stBacking $ storedStorage spub of - StorageDir { dirPath = dir } -> writeFileOnce (keyFilePath dir spub) (BL.fromStrict $ convert $ keyGetData key) - StorageMemory { memKeys = kstore } -> modifyMVar_ kstore $ return . M.insert (refDigest $ storedRef spub) (keyGetData key) + case storedStorage spub of + Storage {..} -> backendStoreKey stBackend (refDigest $ storedRef spub) (keyGetData key) loadKey :: (KeyPair sec pub, MonadIO m, MonadError String m) => Stored pub -> m sec loadKey pub = maybe (throwError $ "secret key not found for " <> show (storedRef pub)) return =<< loadKeyMb pub -loadKeyMb :: (KeyPair sec pub, MonadIO m) => Stored pub -> m (Maybe sec) +loadKeyMb :: forall sec pub m. (KeyPair sec pub, MonadIO m) => Stored pub -> m (Maybe sec) loadKeyMb spub = liftIO $ run $ storedStorage spub where - run st = tryOneLevel (stBacking st) >>= \case - key@Just {} -> return key - Nothing | Just parent <- stParent st -> run parent - | otherwise -> return Nothing - tryOneLevel = \case - StorageDir { dirPath = dir } -> tryIOError (BC.readFile (keyFilePath dir spub)) >>= \case - Right kdata -> return $ keyFromData (convert kdata) spub - Left _ -> return Nothing - StorageMemory { memKeys = kstore } -> (flip keyFromData spub <=< M.lookup (refDigest $ storedRef spub)) <$> readMVar kstore + run :: Storage' c -> IO (Maybe sec) + run Storage {..} = backendLoadKey stBackend (refDigest $ storedRef spub) >>= \case + Just bytes -> return $ keyFromData bytes spub + Nothing + | Just (parent :: Storage) <- cast (backendParent stBackend) -> run parent + | Just (parent :: PartialStorage) <- cast (backendParent stBackend) -> run parent + | otherwise -> return Nothing moveKeys :: MonadIO m => Storage -> Storage -> m () -moveKeys from to = liftIO $ do - case (stBacking from, stBacking to) of - (StorageDir { dirPath = fromPath }, StorageDir { dirPath = toPath }) -> do - files <- listDirectory (fromPath </> "keys") - forM_ files $ \file -> do - renameFile (fromPath </> "keys" </> file) (toPath </> "keys" </> file) - - (StorageDir { dirPath = fromPath }, StorageMemory { memKeys = toKeys }) -> do - let move m file - | Just dgst <- readRefDigest (BC.pack file) = do - let path = fromPath </> "keys" </> file - key <- convert <$> BC.readFile path - removeFile path - return $ M.insert dgst key m - | otherwise = return m - files <- listDirectory (fromPath </> "keys") - modifyMVar_ toKeys $ \keys -> foldM move keys files - - (StorageMemory { memKeys = fromKeys }, StorageDir { dirPath = toPath }) -> do - modifyMVar_ fromKeys $ \keys -> do - forM_ (M.assocs keys) $ \(dgst, key) -> - writeFileOnce (toPath </> "keys" </> (BC.unpack $ showRefDigest dgst)) (BL.fromStrict $ convert key) - return M.empty - - (StorageMemory { memKeys = fromKeys }, StorageMemory { memKeys = toKeys }) -> do - when (fromKeys /= toKeys) $ do - modifyMVar_ fromKeys $ \fkeys -> do - modifyMVar_ toKeys $ return . M.union fkeys - return M.empty +moveKeys Storage { stBackend = from } Storage { stBackend = to } = liftIO $ do + keys <- backendListKeys from + forM_ keys $ \key -> do + backendLoadKey from key >>= \case + Just sec -> do + backendStoreKey to key sec + backendRemoveKey from key + Nothing -> return () diff --git a/src/Erebos/Storage/Memory.hs b/src/Erebos/Storage/Memory.hs new file mode 100644 index 0000000..677e8c5 --- /dev/null +++ b/src/Erebos/Storage/Memory.hs @@ -0,0 +1,101 @@ +module Erebos.Storage.Memory ( + memoryStorage, + deriveEphemeralStorage, + derivePartialStorage, +) where + +import Control.Concurrent.MVar + +import Data.ByteArray (ScrubbedBytes) +import Data.ByteString.Lazy qualified as BL +import Data.Function +import Data.Kind +import Data.List +import Data.Map (Map) +import Data.Map qualified as M +import Data.Maybe +import Data.Typeable + +import Erebos.Object +import Erebos.Storage.Backend +import Erebos.Storage.Head +import Erebos.Storage.Internal + + +data MemoryStorage p (c :: Type -> Type) = StorageMemory + { memParent :: p + , memHeads :: MVar [ (( HeadTypeID, HeadID ), RefDigest ) ] + , memObjs :: MVar (Map RefDigest BL.ByteString) + , memKeys :: MVar (Map RefDigest ScrubbedBytes) + , memWatchers :: MVar WatchList + } + +instance Eq (MemoryStorage p c) where + (==) = (==) `on` memObjs + +instance Show (MemoryStorage p c) where + show StorageMemory {} = "mem" + +instance (StorageCompleteness c, Typeable p) => StorageBackend (MemoryStorage p c) where + type BackendCompleteness (MemoryStorage p c) = c + type BackendParent (MemoryStorage p c) = p + backendParent = memParent + + backendLoadBytes StorageMemory {..} dgst = + M.lookup dgst <$> readMVar memObjs + + backendStoreBytes StorageMemory {..} dgst raw = + modifyMVar_ memObjs (return . M.insert dgst raw) + + + backendLoadHeads StorageMemory {..} tid = do + let toRes ( ( tid', hid ), dgst ) + | tid' == tid = Just ( hid, dgst ) + | otherwise = Nothing + catMaybes . map toRes <$> readMVar memHeads + + backendLoadHead StorageMemory {..} tid hid = + lookup (tid, hid) <$> readMVar memHeads + + backendStoreHead StorageMemory {..} tid hid dgst = + modifyMVar_ memHeads $ return . (( ( tid, hid ), dgst ) :) + + backendReplaceHead StorageMemory {..} tid hid expected new = do + res <- modifyMVar memHeads $ \hs -> do + ws <- map wlFun . filter ((==(tid, hid)) . wlHead) . wlList <$> readMVar memWatchers + return $ case partition ((==(tid, hid)) . fst) hs of + ( [] , _ ) -> ( hs, Left Nothing ) + (( _, dgst ) : _, hs' ) + | dgst == expected -> ((( tid, hid ), new ) : hs', Right ( new, ws )) + | otherwise -> ( hs, Left $ Just dgst ) + case res of + Right ( dgst, ws ) -> mapM_ ($ dgst) ws >> return (Right dgst) + Left x -> return $ Left x + + backendWatchHead StorageMemory {..} tid hid cb = modifyMVar memWatchers $ return . watchListAdd tid hid cb + + backendUnwatchHead StorageMemory {..} wid = modifyMVar_ memWatchers $ return . watchListDel wid + + + backendListKeys StorageMemory {..} = M.keys <$> readMVar memKeys + backendLoadKey StorageMemory {..} dgst = M.lookup dgst <$> readMVar memKeys + backendStoreKey StorageMemory {..} dgst key = modifyMVar_ memKeys $ return . M.insert dgst key + backendRemoveKey StorageMemory {..} dgst = modifyMVar_ memKeys $ return . M.delete dgst + + +memoryStorage' :: (StorageCompleteness c, Typeable p) => p -> IO (Storage' c) +memoryStorage' memParent = do + memHeads <- newMVar [] + memObjs <- newMVar M.empty + memKeys <- newMVar M.empty + memWatchers <- newMVar (WatchList startWatchID []) + newStorage $ StorageMemory {..} + +memoryStorage :: IO Storage +memoryStorage = memoryStorage' () + +deriveEphemeralStorage :: Storage -> IO Storage +deriveEphemeralStorage parent = memoryStorage' parent + +derivePartialStorage :: Storage -> IO PartialStorage +derivePartialStorage parent = memoryStorage' parent diff --git a/src/Erebos/Storage/Merge.hs b/src/Erebos/Storage/Merge.hs index a3b0fd7..41725af 100644 --- a/src/Erebos/Storage/Merge.hs +++ b/src/Erebos/Storage/Merge.hs @@ -31,7 +31,8 @@ import Data.Set qualified as S import System.IO.Unsafe (unsafePerformIO) -import Erebos.Storage +import Erebos.Object +import Erebos.Storable import Erebos.Storage.Internal import Erebos.Util |