leveldb-haskell 0.4.1 → 0.4.1.1

raw patch · 2 files changed

+30/−11 lines, 2 filesPVP ok

version bump matches the API change (PVP)

API changes (from Hackage documentation)

Files

• leveldb-haskell.cabal +1/−1
• src/Database/LevelDB/Streaming.hs +29/−10

@@ -1,5 +1,5 @@ name:                leveldb-haskell-version:             0.4.1+version:             0.4.1.1 synopsis:            Haskell bindings to LevelDB homepage:            http://github.com/kim/leveldb-haskell bug-reports:         http://github.com/kim/leveldb-haskell/issues

@@ -30,6 +30,7 @@     , Entry      -- * Constructing streams+    -- $caveats     , keySlice     , entrySlice @@ -61,13 +62,36 @@ type Entry = (Key, Value)  +-- $caveats+-- Caveats:+--+-- * remember that 'Iterator's are /not/ threadsafe+-- * consider that traversing a 'Stream' mutates the underlying 'Iterator', so+-- the above applies to the 'Stream' as well+-- * because of the destructive update semantics of 'Iterator's, the following+-- example will (perhaps obviously) /not/ work as expected:+--+-- > withIter db def $ \ i ->+-- >     toList $ zip (keySlice i AllKeys Asc) (keySlice i AllKeys Desc)+--+-- However, the following /will/ work:+--+-- > withIter db def $ \ i ->+-- >     foldl (+) 0 . map (*2) . map ByteString.length $ keySlice i AllKeys Asc+--+-- Here, fusion ensures the key slice is traversed only once, while the next+-- example will incur rewinding the 'Iterator' and traversing it a second time:+--+-- > withIter db def $ \ i ->+-- >     let slice   = keySlice i AllKeys Asc+-- >         count f = foldl' (\ c k -> c + f k) 0+-- >      in liftM2 (+) (count ByteString.length slice) (count (const 1) slice)+--+-- To summarise: it is recommended to always create 'Stream's with their own+-- exclusive 'Iterator', and to not share them across threads.+ -- | Create a 'Stream' which yields only the keys of the given 'KeyRange' (in -- the given 'Direction').------ Since traversing the 'Stream' mutates the state of the underlying 'Iterator',--- it is obviously __unsafe__ to share the latter (between threads, or when--- 'Data.Stream.Monadic.zip'ping). Hence, it is __highly__ recommended to create--- a new 'Iterator' for each 'Stream'. keySlice :: (Applicative m, MonadIO m)          => Iterator          -> KeyRange@@ -97,11 +121,6 @@  -- | Create a 'Stream' which yields key/value pairs of the given 'KeyRange' (in -- the given 'Direction').------ Since traversing the 'Stream' mutates the state of the underlying 'Iterator',--- it is obviously __unsafe__ to share the latter (between threads, or when--- 'Data.Stream.Monadic.zip'ping). Hence, it is __highly__ recommended to create--- a new 'Iterator' for each 'Stream'. entrySlice :: (Applicative m, MonadIO m)            => Iterator            -> KeyRange