From a399e81925bac6f281a37c3e1ae859087c38bb6d Mon Sep 17 00:00:00 2001 From: Tony Hannan Date: Wed, 26 Jan 2011 14:25:12 -0500 Subject: [PATCH] Access monad no longer needs to be a MonadMVar --- Database/MongoDB/Query.hs | 32 ++++++++++++++++++++++++++------ mongoDB.cabal | 6 +++--- 2 files changed, 29 insertions(+), 9 deletions(-) diff --git a/Database/MongoDB/Query.hs b/Database/MongoDB/Query.hs index baf531c..26d46ba 100644 --- a/Database/MongoDB/Query.hs +++ b/Database/MongoDB/Query.hs @@ -70,11 +70,30 @@ access w mos pool act = do either (return . Left . ConnectionFailure) (runAction act w mos) ePipe -- | A monad with access to a 'Pipe', 'MasterOrSlaveOk', and 'WriteMode', and throws 'Failure' on read, write, or pipe failure -class (Context Pipe m, Context MasterOrSlaveOk m, Context WriteMode m, Throw Failure m, MonadIO' m, MonadMVar m) => Access m -instance (Context Pipe m, Context MasterOrSlaveOk m, Context WriteMode m, Throw Failure m, MonadIO' m, MonadMVar m) => Access m +class (Context Pipe m, Context MasterOrSlaveOk m, Context WriteMode m, Throw Failure m, MonadIO' m) => Access m +instance (Context Pipe m, Context MasterOrSlaveOk m, Context WriteMode m, Throw Failure m, MonadIO' m) => Access m + +wrapIO :: (Access m) => (WriteMode -> MasterOrSlaveOk -> Pipe -> IO (Either Failure a)) -> m a +-- ^ Lift IO with Access context and failure into Access monad +wrapIO act = do + writeMod <- context + mos <- context + pipe <- context + e <- liftIO (act writeMod mos pipe) + either throw return e + +modifyMVar' :: (Access m) => MVar a -> (a -> Action IO (a, b)) -> m b +modifyMVar' var act = wrapIO $ \w m p -> modifyMVar var $ \a -> do + e <- runAction (act a) w m p + return $ either ((a,) . Left) (Right <$>) e + +addMVarFinalizer' :: (Access m) => MVar a -> Action IO () -> m () +addMVarFinalizer' var act = wrapIO $ \w m p -> do + addMVarFinalizer var $ runAction act w m p >> return () -- ignore any failure + return (Right ()) newtype Action m a = Action (ErrorT Failure (ReaderT WriteMode (ReaderT MasterOrSlaveOk (ReaderT Pipe m))) a) - deriving (Context Pipe, Context MasterOrSlaveOk, Context WriteMode, Throw Failure, MonadIO, MonadMVar, Monad, Applicative, Functor) + deriving (Context Pipe, Context MasterOrSlaveOk, Context WriteMode, Throw Failure, MonadIO, Monad, Applicative, Functor) -- ^ Monad with access to a 'Pipe', 'MasterOrSlaveOk', and 'WriteMode', and throws a 'Failure' on read, write or pipe failure instance MonadTrans Action where @@ -440,13 +459,14 @@ newCursor :: (Access m) => Database -> Collection -> BatchSize -> DelayedCursorS newCursor (Database db) col batch cs = do var <- newMVar cs let cursor = Cursor (db <.> col) batch var - addMVarFinalizer var (closeCursor cursor) + addMVarFinalizer' var (closeCursor cursor) return cursor next :: (Access m) => Cursor -> m (Maybe Document) -- ^ Return next document in query result, or Nothing if finished. -next (Cursor fcol batch var) = modifyMVar var nextState where +next (Cursor fcol batch var) = modifyMVar' var nextState where -- Pre-fetch next batch promise from server when last one in current batch is returned. + nextState:: DelayedCursorState -> Action IO (DelayedCursorState, Maybe Document) nextState dcs = do CS limit cid docs <- mapErrorIO id dcs case docs of @@ -470,7 +490,7 @@ rest :: (Access m) => Cursor -> m [Document] rest c = loop (next c) closeCursor :: (Access m) => Cursor -> m () -closeCursor (Cursor _ _ var) = modifyMVar var kill' where +closeCursor (Cursor _ _ var) = modifyMVar' var kill' where kill' dcs = first return <$> (kill =<< mapErrorIO id dcs) kill (CS _ cid _) = (CS 0 0 [],) <$> if cid == 0 then return () else send [KillCursors [cid]] diff --git a/mongoDB.cabal b/mongoDB.cabal index dca2bbf..eb68eb0 100644 --- a/mongoDB.cabal +++ b/mongoDB.cabal @@ -1,5 +1,5 @@ name: mongoDB -version: 0.9.1 +version: 0.9.2 build-type: Simple license: OtherLicense license-file: LICENSE @@ -21,8 +21,8 @@ stability: alpha homepage: http://github.com/TonyGen/mongoDB-haskell package-url: bug-reports: -synopsis: A driver for MongoDB -description: This module lets you connect to MongoDB (www.mongodb.org) and do inserts, queries, updates, etc. +synopsis: MongoDB driver +description: This module lets you connect to MongoDB (www.mongodb.org) and do inserts, queries, updates, etc. Please see the example in Database.MongoDB and the tutorial from the homepage. category: Database author: Tony Hannan & Scott Parish tested-with: