Add GHC.IO.Handle.FD.openFileBlocking (#4248)

[ghc-base.git] / GHC / IO / FD.hs

diff --git a/GHC/IO/FD.hs b/GHC/IO/FD.hs
index 659f610..012bb73 100644 (file)
--- a/GHC/IO/FD.hs
+++ b/GHC/IO/FD.hs
@@ -1,6 +1,13 @@
-{-# OPTIONS_GHC -XNoImplicitPrelude -XBangPatterns -fno-warn-identities #-}
+{-# LANGUAGE CPP
+           , NoImplicitPrelude
+           , BangPatterns
+           , ForeignFunctionInterface
+           , DeriveDataTypeable
+  #-}
+{-# OPTIONS_GHC -fno-warn-identities #-}
 -- Whether there are identities depends on the platform
 {-# OPTIONS_HADDOCK hide #-}
+
 -----------------------------------------------------------------------------
 -- |
 -- Module      :  GHC.IO.FD
@@ -99,8 +106,15 @@ instance GHC.IO.Device.IODevice FD where
   dup           = dup
   dup2          = dup2
 
+-- We used to use System.Posix.Internals.dEFAULT_BUFFER_SIZE, which is
+-- taken from the value of BUFSIZ on the current platform.  This value
+-- varies too much though: it is 512 on Windows, 1024 on OS X and 8192
+-- on Linux.  So let's just use a decent size on every platform:
+dEFAULT_FD_BUFFER_SIZE :: Int
+dEFAULT_FD_BUFFER_SIZE = 8096
+
 instance BufferedIO FD where
-  newBuffer _dev state = newByteBuffer dEFAULT_BUFFER_SIZE state
+  newBuffer _dev state = newByteBuffer dEFAULT_FD_BUFFER_SIZE state
   fillReadBuffer    fd buf = readBuf' fd buf
   fillReadBuffer0   fd buf = readBufNonBlocking fd buf
   flushWriteBuffer  fd buf = writeBuf' fd buf
@@ -127,8 +141,8 @@ writeBuf' fd buf = do
 -- | Open a file and make an 'FD' for it.  Truncates the file to zero
 -- size when the `IOMode` is `WriteMode`.  Puts the file descriptor
 -- into non-blocking mode on Unix systems.
-openFile :: FilePath -> IOMode -> IO (FD,IODeviceType)
-openFile filepath iomode =
+openFile :: FilePath -> IOMode -> Bool -> IO (FD,IODeviceType)
+openFile filepath iomode non_blocking =
   withFilePath filepath $ \ f ->
 
     let 
@@ -148,7 +162,10 @@ openFile filepath iomode =
       binary_flags = 0
 #endif      
 
-      oflags = oflags1 .|. binary_flags
+      oflags2 = oflags1 .|. binary_flags
+
+      oflags | non_blocking = oflags2 .|. nonblock_flags
+             | otherwise    = oflags2
     in do
 
     -- the old implementation had a complicated series of three opens,
@@ -157,11 +174,12 @@ openFile filepath iomode =
     -- always returns EISDIR if the file is a directory and was opened
     -- for writing, so I think we're ok with a single open() here...
     fd <- throwErrnoIfMinus1Retry "openFile"
-                (c_open f oflags 0o666)
+                (if non_blocking then c_open      f oflags 0o666
+                                 else c_safe_open f oflags 0o666)
 
     (fD,fd_type) <- mkFD fd iomode Nothing{-no stat-}
                             False{-not a socket-} 
-                            True{-is non-blocking-}
+                            non_blocking
             `catchAny` \e -> do _ <- c_close fd
                                 throwIO e
 
@@ -177,13 +195,14 @@ openFile filepath iomode =
     return (fD,fd_type)
 
 std_flags, output_flags, read_flags, write_flags, rw_flags,
-    append_flags :: CInt
-std_flags    = o_NONBLOCK   .|. o_NOCTTY
+    append_flags, nonblock_flags :: CInt
+std_flags    = o_NOCTTY
 output_flags = std_flags    .|. o_CREAT
 read_flags   = std_flags    .|. o_RDONLY 
 write_flags  = output_flags .|. o_WRONLY
 rw_flags     = output_flags .|. o_RDWR
 append_flags = write_flags  .|. o_APPEND
+nonblock_flags = o_NONBLOCK
 
 
 -- | Make a 'FD' from an existing file descriptor.  Fails if the FD