[newlib-cygwin] Cygwin: console: Fix SIGWINCH handling in Win7.

[Corinna Vinschen <corinna@sourceware.org>]

https://sourceware.org/git/gitweb.cgi?p=newlib-cygwin.git;h=2b9219b4a54e897d6a5ae6815d75ffec4de1f785

commit 2b9219b4a54e897d6a5ae6815d75ffec4de1f785
Author: Takashi Yano via Cygwin-patches <cygwin-patches@cygwin.com>
Date:   Thu Feb 18 18:01:27 2021 +0900

    Cygwin: console: Fix SIGWINCH handling in Win7.
    
    - If ENABLE_VIRTUAL_TERMINAL_INPUT is not set, changing window height
      does not generate WINDOW_BUFFER_SIZE_EVENT. This happens if console
      is in the legacy mode. Therefore, with this patch, the windows size
      is checked every time in cons_master_thread() if the cosole is in
      the legacy mode.

Diff:
---
 winsup/cygwin/fhandler_console.cc | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/winsup/cygwin/fhandler_console.cc b/winsup/cygwin/fhandler_console.cc
index 5053cb053..4dee506dd 100644
--- a/winsup/cygwin/fhandler_console.cc
+++ b/winsup/cygwin/fhandler_console.cc
@@ -223,6 +223,21 @@ fhandler_console::cons_master_thread (handle_set_t *p, tty *ttyp)
 	  ReleaseMutex (p->input_mutex);
 	  return;
 	}
+      /* If ENABLE_VIRTUAL_TERMINAL_INPUT is not set, changing
+	 window height does not generate WINDOW_BUFFER_SIZE_EVENT.
+	 Therefore, check windows size every time here. */
+      if (!wincap.has_con_24bit_colors () || con_is_legacy)
+	{
+	  SHORT y = con.dwWinSize.Y;
+	  SHORT x = con.dwWinSize.X;
+	  con.fillin (p->output_handle);
+	  if (y != con.dwWinSize.Y || x != con.dwWinSize.X)
+	    {
+	      con.scroll_region.Top = 0;
+	      con.scroll_region.Bottom = -1;
+	      ttyp->kill_pgrp (SIGWINCH);
+	    }
+	}
       for (i = 0; i < total_read; i++)
 	{
 	  const char c = input_rec[i].Event.KeyEvent.uChar.AsciiChar;