* fhandler.cc (fhandler_base::get_readahead_into_buffer): New function.

* fhandler.h: Declare new function.  Add extra argument to
process_slave_output.
* fhandler_console.cc (fhandler_console::read): Move read ahead code to new
function.
* fhandler_tty.cc (fhandler_pty_master::process_slave_output): Move common code
here.
(fhandler_tty_slave::read): Understand readahead.
(fhandler_pty_master::read): Move code to process_slave_output.
* select.cc (peek_pipe): Avoid performing certain checks when non-read and on
inappropriate fh types.

winsup/cygwin/fhandler_console.cc

@@ -115,20 +115,13 @@ fhandler_console::read (void *pv, size_t buflen)
     return 0;
 
   HANDLE h = get_io_handle ();
-  int copied_chars = 0;
 
 #define buf ((char *) pv)
 
   int ch;
   set_input_state ();
-  while (buflen)
-    if ((ch = get_readahead ()) < 0)
-      break;
-    else
-      {
-	buf[copied_chars++] = (unsigned char)(ch & 0xff);
-	buflen--;
-      }
+
+  int copied_chars = get_readahead_into_buffer (buf, buflen);
 
   if (copied_chars)
     return copied_chars;