Allow unix 2.8.6

Author: jasagredo

blockio/blockio.cabal

@@ -93,17 +93,21 @@ library
 
   if os(linux)
     hs-source-dirs: src-linux
-    other-modules:  System.FS.BlockIO.Internal
-    build-depends:  unix ^>=2.8.7
+    build-depends:  unix ^>=2.8.6
+    other-modules:
+      System.FS.BlockIO.Internal
+      System.FS.BlockIO.Internal.Fcntl
 
     if !flag(serialblockio)
       other-modules: System.FS.BlockIO.Async
       build-depends: blockio-uring ^>=0.1
 
   elif os(osx)
     hs-source-dirs: src-macos
-    build-depends:  unix ^>=2.8.7
-    other-modules:  System.FS.BlockIO.Internal
+    build-depends:  unix ^>=2.8.6
+    other-modules:
+      System.FS.BlockIO.Internal
+      System.FS.BlockIO.Internal.Fcntl
 
   elif os(windows)
     hs-source-dirs: src-windows

blockio/src-linux/System/FS/BlockIO/Internal.hs

@@ -1,16 +1,16 @@
 {-# LANGUAGE CPP #-}
-
 module System.FS.BlockIO.Internal (
     ioHasBlockIO
   ) where
 
 import qualified System.FS.API as FS
 import           System.FS.API (FsPath, Handle (..), HasFS)
 import           System.FS.BlockIO.API (Advice (..), FileOffset, HasBlockIO)
+import qualified System.FS.BlockIO.Internal.Fcntl as Fcntl
 import qualified System.FS.BlockIO.IO.Internal as IOI
 import           System.FS.IO (HandleIO)
 import qualified System.FS.IO.Handle as FS
-import qualified System.Posix.Fcntl as Fcntl
+import qualified System.Posix.Fcntl as Fcntl hiding (fileSetCaching)
 import qualified System.Posix.Files as Unix
 import qualified System.Posix.Unistd as Unix
 

blockio/src-linux/System/FS/BlockIO/Internal/Fcntl.hsc

@@ -0,0 +1,26 @@
+{-# LANGUAGE CPP #-}
+module System.FS.BlockIO.Internal.Fcntl (fileSetCaching) where
+
+#if MIN_VERSION_unix(2,8,7)
+
+import System.Posix.Fcntl (fileSetCaching)
+
+#else
+
+#include <fcntl.h>
+
+import           Data.Bits (complement, (.&.), (.|.))
+import           Foreign.C (throwErrnoIfMinus1, throwErrnoIfMinus1_)
+import           System.Posix.Internals
+import           System.Posix.Types (Fd (Fd))
+
+-- | For simplification, we considered that Linux !HAS_F_NOCACHE and HAS_O_DIRECT
+fileSetCaching :: Fd -> Bool -> IO ()
+fileSetCaching (Fd fd) val = do
+    r <- throwErrnoIfMinus1 "fileSetCaching" (c_fcntl_read fd #{const F_GETFL})
+    let r' | val       = fromIntegral r .&. complement opt_val
+           | otherwise = fromIntegral r .|. opt_val
+    throwErrnoIfMinus1_ "fileSetCaching" (c_fcntl_write fd #{const F_SETFL} r')
+  where
+    opt_val = #{const O_DIRECT}
+#endif

blockio/src-macos/System/FS/BlockIO/Internal.hs

@@ -5,11 +5,11 @@ module System.FS.BlockIO.Internal (
 import qualified System.FS.API as FS
 import           System.FS.API (FsPath, Handle (..), HasFS)
 import           System.FS.BlockIO.API (Advice (..), FileOffset, HasBlockIO)
+import qualified System.FS.BlockIO.Internal.Fcntl as Unix
 import qualified System.FS.BlockIO.IO.Internal as IOI
 import qualified System.FS.BlockIO.Serial as Serial
 import           System.FS.IO (HandleIO)
 import qualified System.FS.IO.Handle as FS
-import qualified System.Posix.Fcntl as Unix
 import qualified System.Posix.Files as Unix
 import qualified System.Posix.Unistd as Unix
 

blockio/src-macos/System/FS/BlockIO/Internal/Fcntl.hsc

@@ -0,0 +1,20 @@
+{-# LANGUAGE CPP #-}
+module System.FS.BlockIO.Internal.Fcntl (fileSetCaching) where
+
+#if MIN_VERSION_unix(2,8,7)
+
+import System.Posix.Fcntl (fileSetCaching)
+
+#else
+
+#include <fcntl.h>
+
+import           Foreign.C (throwErrnoIfMinus1_)
+import           System.Posix.Internals
+import           System.Posix.Types (Fd (Fd))
+
+-- | For simplification, we considered that MacOS HAS_F_NOCACHE and !HAS_O_DIRECT
+fileSetCaching :: Fd -> Bool -> IO ()
+fileSetCaching (Fd fd) val = do
+    throwErrnoIfMinus1_ "fileSetCaching" (c_fcntl_write fd #{const F_NOCACHE} (if val then 0 else 1))
+#endif