1 files changed, 49 insertions, 0 deletions
diff --git a/utils/benchmarks/events/EventFile.hs b/utils/benchmarks/events/EventFile.hs
new file mode 100644
index 0000000000..1edad86a89
--- /dev/null
+++ b/utils/benchmarks/events/EventFile.hs
@@ -0,0 +1,49 @@
+{-# LANGUAGE CPP #-}
+
+-- | File functions using System.Event instead of GHC's I/O manager.
+module EventFile
+    (
+      read
+    ) where
+
+import Data.ByteString (ByteString)
+import Data.ByteString.Internal (createAndTrim)
+import Data.Word (Word8)
+import Foreign.Ptr (Ptr, castPtr)
+import Foreign.C.Error (eINTR, getErrno, throwErrno)
+#if __GLASGOW_HASKELL__ < 612
+import GHC.IOBase (IOErrorType(..))
+#else
+import GHC.IO.Exception (IOErrorType(..))
+#endif
+#if defined(USE_GHC_IO_MANAGER)
+import GHC.Conc (threadWaitRead)
+#else
+import GHC.Event (threadWaitRead)
+#endif
+import System.IO.Error (ioeSetErrorString, mkIOError)
+import System.Posix.Internals (c_read)
+import System.Posix.Types (Fd)
+import Prelude hiding (read)
+import EventUtil
+
+read :: Fd -> Int -> IO ByteString
+read fd nbytes
+    | nbytes <= 0 = ioError (mkInvalidReadArgError "read")
+    | otherwise   = createAndTrim nbytes $ readInner fd nbytes
+
+readInner :: Fd -> Int -> Ptr Word8 -> IO Int
+readInner fd nbytes ptr = do
+    len <- throwErrnoIfMinus1Retry_repeatOnBlock "read"
+           (threadWaitRead (fromIntegral fd)) $
+           c_read (fromIntegral fd) (castPtr ptr) (fromIntegral nbytes)
+    case fromIntegral len of
+         (-1) -> do errno <- getErrno
+                    if errno == eINTR
+                       then readInner fd nbytes ptr
+                       else throwErrno "read"
+         n -> return n
+
+mkInvalidReadArgError :: String -> IOError
+mkInvalidReadArgError loc = ioeSetErrorString
+  (mkIOError InvalidArgument loc Nothing Nothing) "non-positive length"