X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=GHC%2FIO%2FHandle%2FInternals.hs;h=6409bbdb33bba389c2face905e8a812b38b993f0;hb=41e8fba828acbae1751628af50849f5352b27873;hp=1e48e8bb434eaa9c1ed2e6afb1f10320e0f0add3;hpb=5522b142e24b9dbba21a9036746db20e78cf8f43;p=ghc-base.git

diff --git a/GHC/IO/Handle/Internals.hs b/GHC/IO/Handle/Internals.hs
index 1e48e8b..6409bbd 100644
--- a/GHC/IO/Handle/Internals.hs
+++ b/GHC/IO/Handle/Internals.hs
@@ -1,7 +1,13 @@
+{-# LANGUAGE NoImplicitPrelude
+           , RecordWildCards
+           , BangPatterns
+           , PatternGuards
+           , NondecreasingIndentation
+           , Rank2Types
+  #-}
 {-# OPTIONS_GHC -fno-warn-unused-matches #-}
 {-# OPTIONS_GHC -fno-warn-name-shadowing #-}
 {-# OPTIONS_HADDOCK hide #-}
-{-# LANGUAGE NoImplicitPrelude, RecordWildCards, BangPatterns #-}
 
 -----------------------------------------------------------------------------
 -- |
@@ -220,7 +226,9 @@ wantWritableHandle :: String -> Handle -> (Handle__ -> IO a) -> IO a
 wantWritableHandle fun h@(FileHandle _ m) act
   = wantWritableHandle' fun h m act
 wantWritableHandle fun h@(DuplexHandle _ _ m) act
-  = withHandle_' fun h m  act
+  = wantWritableHandle' fun h m act
+    -- we know it's not a ReadHandle or ReadWriteHandle, but we have to
+    -- check for ClosedHandle/SemiClosedHandle. (#4808)
 
 wantWritableHandle'
         :: String -> Handle -> MVar Handle__
@@ -257,7 +265,9 @@ wantReadableHandle_ :: String -> Handle -> (Handle__ -> IO a) -> IO a
 wantReadableHandle_ fun h@(FileHandle  _ m)   act
   = wantReadableHandle' fun h m act
 wantReadableHandle_ fun h@(DuplexHandle _ m _) act
-  = withHandle_' fun h m act
+  = wantReadableHandle' fun h m act
+    -- we know it's not a WriteHandle or ReadWriteHandle, but we have to
+    -- check for ClosedHandle/SemiClosedHandle. (#4808)
 
 wantReadableHandle'
         :: String -> Handle -> MVar Handle__
@@ -386,7 +396,7 @@ handleFinalizer fp m = do
 -- using an 8k char buffer instead of 32k improved performance for a
 -- basic "cat" program by ~30% for me.  --SDM
 dEFAULT_CHAR_BUFFER_SIZE :: Int
-dEFAULT_CHAR_BUFFER_SIZE = dEFAULT_BUFFER_SIZE `div` 4
+dEFAULT_CHAR_BUFFER_SIZE = 2048 -- 8k/sizeof(HsChar)
 
 getCharBuffer :: IODevice dev => dev -> BufferState
               -> IO (IORef CharBuffer, BufferMode)