[newlib-cygwin] Cygwin: pty: Stop counting number of slaves attached to pseudo console.

[newlib-cygwin] Cygwin: pty: Stop counting number of slaves attached to pseudo console.

[Corinna Vinschen]

https://sourceware.org/git/gitweb.cgi?p=newlib-cygwin.git;h=8d7a5b39d2fa3fe009dfae3fe90d6d2e9962f98e

commit 8d7a5b39d2fa3fe009dfae3fe90d6d2e9962f98e
Author: Takashi Yano via Cygwin-patches <cygwin-patches@cygwin.com>
Date:   Mon May 25 17:49:08 2020 +0900

    Cygwin: pty: Stop counting number of slaves attached to pseudo console.
    
    - The number of slaves attached to pseudo console is used only for
      triggering redraw screen. Counting was not only needless, but also
      did not work as expected. This patch removes the code for counting.

Diff:
---
 winsup/cygwin/fhandler_tty.cc | 22 +++++-----------------
 winsup/cygwin/tty.cc          |  3 +--
 winsup/cygwin/tty.h           |  1 -
 3 files changed, 6 insertions(+), 20 deletions(-)

diff --git a/winsup/cygwin/fhandler_tty.cc b/winsup/cygwin/fhandler_tty.cc
index 5faf896e4..df08dd20a 100644
--- a/winsup/cygwin/fhandler_tty.cc
+++ b/winsup/cygwin/fhandler_tty.cc
@@ -1019,8 +1019,6 @@ fhandler_pty_slave::close ()
   fhandler_pty_common::close ();
   if (!ForceCloseHandle (output_mutex))
     termios_printf ("CloseHandle (output_mutex<%p>), %E", output_mutex);
-  if (pcon_attached_to == get_minor ())
-    get_ttyp ()->num_pcon_attached_slaves --;
   return 0;
 }
 
@@ -2924,21 +2922,11 @@ fhandler_pty_slave::fixup_after_attach (bool native_maybe, int fd_set)
     {
       if (fhandler_console::get_console_process_id (get_helper_process_id (),
 						    true))
-	{
-	  if (pcon_attached_to != get_minor ())
-	    {
-	      pcon_attached_to = get_minor ();
-	      init_console_handler (true);
-	    }
-	  /* Clear screen to synchronize pseudo console screen buffer
-	     with real terminal. This is necessary because pseudo
-	     console screen buffer is empty at start. */
-	  if (get_ttyp ()->num_pcon_attached_slaves == 0)
-	    /* Assume this is the first process using this pty slave. */
-	    get_ttyp ()->need_redraw_screen = true;
-
-	  get_ttyp ()->num_pcon_attached_slaves ++;
-	}
+	if (pcon_attached_to != get_minor ())
+	  {
+	    pcon_attached_to = get_minor ();
+	    init_console_handler (true);
+	  }
 
 #if 0 /* This is for debug only. */
       isHybrid = true;
diff --git a/winsup/cygwin/tty.cc b/winsup/cygwin/tty.cc
index 3fc46fb29..efdae4697 100644
--- a/winsup/cygwin/tty.cc
+++ b/winsup/cygwin/tty.cc
@@ -242,9 +242,8 @@ tty::init ()
   screen_alternated = false;
   mask_switch_to_pcon_in = false;
   pcon_pid = 0;
-  num_pcon_attached_slaves = 0;
   term_code_page = 0;
-  need_redraw_screen = false;
+  need_redraw_screen = true;
   fwd_done = NULL;
   pcon_last_time = 0;
   pcon_in_empty = true;
diff --git a/winsup/cygwin/tty.h b/winsup/cygwin/tty.h
index c4dd2e458..7d6fc8fef 100644
--- a/winsup/cygwin/tty.h
+++ b/winsup/cygwin/tty.h
@@ -103,7 +103,6 @@ private:
   bool screen_alternated;
   bool mask_switch_to_pcon_in;
   pid_t pcon_pid;
-  int num_pcon_attached_slaves;
   UINT term_code_page;
   bool need_redraw_screen;
   HANDLE fwd_done;