src/Database/PostgreSQL/LibPQ/Internal.hs

-----------------------------------------------------------------------------
-- |
-- Module : Database.PostgreSQL.LibPQ.Internal
-- Copyright : (c) 2010 Grant Monroe,
-- (c) 2011 Leon P Smith
-- License : BSD3
--
-- This module exports the data constructor for the database connection
-- object so that people may create their own foreign bindings to libpq
-- functions that may not exist yet in vanilla postgresql-libpq.
--
-----------------------------------------------------------------------------

{-# LANGUAGE BangPatterns, EmptyDataDecls #-}

module Database.PostgreSQL.LibPQ.Internal where

import Foreign
import Control.Concurrent.MVar ( MVar )


-- | 'Connection' encapsulates a connection to the backend.
data Connection = Conn {-# UNPACK #-} !(ForeignPtr PGconn)
 {-# UNPACK #-} !(MVar NoticeBuffer)

instance Eq Connection where
 (Conn c _) == (Conn d _) = c == d
 (Conn c _) /= (Conn d _) = c /= d

withConn :: Connection
 -> (Ptr PGconn -> IO b)
 -> IO b
withConn (Conn !fp _) f = withForeignPtr fp f
{-# INLINE withConn #-}

data PGconn

data CNoticeBuffer
type NoticeBuffer = Ptr CNoticeBuffer