[project @ 2002-06-18 13:01:43 by simonmar]

Fix bug in the implementation of hGetLine: on finding the EOF when we
have a partial line in our hands, we weren't resetting the state of
the buffer to empty, so the same partial line would be returned for
each subsequent call to hGetLine.

diff --git a/GHC/IO.hs b/GHC/IO.hs
index 9467c53..b3d590a 100644 (file)
--- a/GHC/IO.hs
+++ b/GHC/IO.hs
@@ -168,10 +168,13 @@ hGetLineBufferedLoop handle_ ref
 #endif
 
   xs <- unpack raw r off
+
+  -- if eol == True, then off is the offset of the '\n'
+  -- otherwise off == w and the buffer is now empty.
   if eol
-       then do if w == off + 1
-                  then writeIORef ref buf{ bufRPtr=0, bufWPtr=0 }
-                  else writeIORef ref buf{ bufRPtr = off + 1 }
+       then do if (w == off + 1)
+                       then writeIORef ref buf{ bufRPtr=0, bufWPtr=0 }
+                       else writeIORef ref buf{ bufRPtr = off + 1 }
                return (concat (reverse (xs:xss)))
        else do
             maybe_buf <- maybeFillReadBuffer (haFD handle_) True (haIsStream handle_)
@@ -179,10 +182,12 @@ hGetLineBufferedLoop handle_ ref
             case maybe_buf of
                -- Nothing indicates we caught an EOF, and we may have a
                -- partial line to return.
-               Nothing -> let str = concat (reverse (xs:xss)) in
-                          if not (null str)
-                             then return str
-                             else ioe_EOF
+               Nothing -> do
+                    writeIORef ref buf{ bufRPtr=0, bufWPtr=0 }
+                    let str = concat (reverse (xs:xss))
+                    if not (null str)
+                       then return str
+                       else ioe_EOF
                Just new_buf -> 
                     hGetLineBufferedLoop handle_ ref new_buf (xs:xss)