Prepared statement storage

VyacheslavHashov · VyacheslavHashov · commit 47e3488fd396 · 2017-01-16T20:58:12.000+03:00
diff --git a/postgres-wire.cabal b/postgres-wire.cabal
@@ -21,13 +21,16 @@ library
                      , Database.PostgreSQL.Protocol.Connection
                      , Database.PostgreSQL.Protocol.Encoders
                      , Database.PostgreSQL.Protocol.Decoders
+                     , Database.PostgreSQL.Protocol.StatementStorage
   build-depends:       base >= 4.7 && < 5
                      , bytestring
                      , socket
                      , socket-unix
                      , vector
                      , binary
                      , time
+                     , hashable
+                     , hashtables
   default-language:    Haskell2010
   default-extensions:  OverloadedStrings
 
diff --git a/src/Database/PostgreSQL/Protocol/StatementStorage.hs b/src/Database/PostgreSQL/Protocol/StatementStorage.hs
@@ -0,0 +1,28 @@
+module Database.PostgreSQL.Protocol.StatementStorage where
+
+import qualified Data.HashTable.IO as H
+import qualified Data.ByteString as B
+import Data.ByteString.Char8 (pack)
+import Data.Word (Word)
+import Data.IORef
+
+import Database.PostgreSQL.Protocol.Types
+
+-- | Prepared statement storage
+data StatementStorage = StatementStorage
+    (H.CuckooHashTable StatementSQL StatementName) (IORef Word)
+
+newStatementStorage :: IO StatementStorage
+newStatementStorage = StatementStorage <$> H.new <*> newIORef 0
+
+lookupStatement :: StatementStorage -> StatementSQL -> IO (Maybe StatementName)
+lookupStatement (StatementStorage table _) = H.lookup table
+
+storageStatement :: StatementStorage -> StatementSQL -> IO StatementName
+storageStatement (StatementStorage table counter) stmt = do
+    n <- readIORef counter
+    writeIORef counter $ n + 1
+    let name = pack $ show n
+    H.insert table name stmt
+    pure name
+
