From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 24403 invoked by alias); 27 Jul 2016 14:32:09 -0000 Mailing-List: contact cygwin-help@cygwin.com; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: cygwin-owner@cygwin.com Mail-Followup-To: cygwin@cygwin.com Received: (qmail 24393 invoked by uid 89); 27 Jul 2016 14:32:08 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=0.7 required=5.0 tests=AWL,BAYES_50,RCVD_IN_DNSWL_LOW,SPF_PASS autolearn=ham version=3.3.2 spammy=D*kylheku.com, cy, U*kaz, kazkylhekucom X-HELO: smtp-out-no.shaw.ca Received: from smtp-out-no.shaw.ca (HELO smtp-out-no.shaw.ca) (64.59.134.12) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with (AES256-GCM-SHA384 encrypted) ESMTPS; Wed, 27 Jul 2016 14:31:55 +0000 Received: from kylheku.com ([24.85.175.81]) by shaw.ca with SMTP id SPsFbZpytxBmMSPsGb8tb4; Wed, 27 Jul 2016 08:31:53 -0600 X-Authority-Analysis: v=2.2 cv=DLzN2GFb c=1 sm=1 tr=0 a=WiYoHcCliNeVponEdG0Ckg==:117 a=WiYoHcCliNeVponEdG0Ckg==:17 a=L9H7d07YOLsA:10 a=9cW_t1CCXrUA:10 a=s5jvgZ67dGcA:10 a=cAmyUtKerLwA:10 a=2KUf1mbJAAAA:8 a=ejQruhyicXs5b7heL3gA:9 a=LME9DoRMzU6P72L8X6EC:22 Received: from www-data by kylheku.com with local (Exim 4.72) (envelope-from ) id 1bSPsE-0002eV-Aj for cygwin@cygwin.com; Wed, 27 Jul 2016 07:31:50 -0700 To: Cygwin Subject: [PATCH] Strange behavior of cmd.exe when hammered with clear screen operations from Cygwin program. X-PHP-Originating-Script: 501:rcmail.php MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: quoted-printable Date: Wed, 27 Jul 2016 14:32:00 -0000 From: Kaz Kylheku In-Reply-To: <9b05b6502dc0bdba2654069cfa924a50@mail.kylheku.com> References: <05e87c9326e8bc9a32a5a3cd2511fe98@mail.kylheku.com> <9b05b6502dc0bdba2654069cfa924a50@mail.kylheku.com> Message-ID: <6d026b0ea424481879a89d480730c1f4@mail.kylheku.com> X-Sender: kaz@kylheku.com User-Agent: Roundcube Webmail/0.9.2 X-CMAE-Envelope: MS4wfI+bYgBw0ndn0ZFN0BfpNNq8ZMKpzstc6KHy1Ta/KeZ5ofbEYxXOr9jh7x5+8a1cVSMsEgxw3Sjvf3RG6kKTOF/MMHkwuhnU2oupKuIeiO3wgC2V0mm7 +oCbP1ubZWxtCBinsTePqR2I1Xu38wa+LoHo+3KzBAexyaM0KrGKsi6R X-SW-Source: 2016-07/txt/msg00320.txt.bz2 The patch below seems to solves it for me: Cygwin should not be faking a scroll of the console by shrinking it and then restoring its size. Though clever, this is evidently unreliable; cmd.exe misbehaves if the console handle is hit with rapid SetConsoleScreenBufferSize calls. ------------ From: Kaz Kylheku Date: Wed, 27 Jul 2016 07:12:54 -0700 Subject: Replace bogus resize-window-to-clear-screen logic. This removes (ab)uses of SetConsoleScreenBufferSize which sometimes cause cmd.exe to badly misbehave. It probably doesn't like the closely spaced timing of shrinking the window down to one line followed by a restore of the size. Instead we just output newlines to clear the window. * winsup/cygwin/fhandler.h (dev_console::scroll_window): Member function declaration removed. (dev_console::clear_should_scroll): New member function declared. * winsup/cygwin/fhandler_console.cc (dev_console::scroll_window): Member function removed. (dev_console::clear_should_scroll): New member function. Performs only the test that was performed by scroll_window, not the actual scrolling. The scrolling is now done in the caller in the fhandler_console class. (fhandler_console::clear_screen): Call con.clear_should_scroll instead of con.scroll_window. If this returns false, act as before. Otherwise, clear the screen by scrolling the window. This is done not by making SetConsoleScreenBufferSize calls to shrink and restore the window, but by earnestly emitting a number of carriage returns equal to the vertical screen size and then restoring the cursor position. diff --git a/winsup/cygwin/fhandler.h b/winsup/cygwin/fhandler.h index 21c71d7..4af584b 100644 --- a/winsup/cygwin/fhandler.h +++ b/winsup/cygwin/fhandler.h @@ -1361,7 +1361,7 @@ class dev_console int set_cl_x (cltype); int set_cl_y (cltype); bool fillin (HANDLE); - bool __reg3 scroll_window (HANDLE, int, int, int, int); + bool __reg3 clear_should_scroll (HANDLE, int, int, int, int); void __reg3 scroll_buffer (HANDLE, int, int, int, int, int, int); void __reg3 clear_screen (HANDLE, int, int, int, int); void __reg3 save_restore (HANDLE, char); diff --git a/winsup/cygwin/fhandler_console.cc=20 b/winsup/cygwin/fhandler_console.cc index 5fe4480..f4806e0 100644 --- a/winsup/cygwin/fhandler_console.cc +++ b/winsup/cygwin/fhandler_console.cc @@ -1209,38 +1209,11 @@ dev_console::set_cl_y (cltype y) } bool -dev_console::scroll_window (HANDLE h, int x1, int y1, int x2, int y2) +dev_console::clear_should_scroll (HANDLE h, int x1, int y1, int x2, int=20 y2) { if (save_buf || x1 !=3D 0 || x2 !=3D dwWinSize.X - 1 || y1 !=3D=20 b.srWindow.Top || y2 !=3D b.srWindow.Bottom || b.dwSize.Y <=3D dwWinSize.Y) return false; - - SMALL_RECT sr; - int toscroll =3D 2 + dwEnd.Y - b.srWindow.Top; - int shrink =3D 1 + toscroll + b.srWindow.Bottom - b.dwSize.Y; - sr.Left =3D sr.Right =3D dwEnd.X =3D 0; - /* Can't increment dwEnd yet since we may not have space in - the buffer. */ - SetConsoleCursorPosition (h, dwEnd); - if (shrink > 0) - { - COORD c =3D b.dwSize; - c.Y =3D dwEnd.Y - shrink; - SetConsoleScreenBufferSize (h, c); - SetConsoleScreenBufferSize (h, b.dwSize); - dwEnd.Y =3D 0; - fillin (h); - toscroll =3D 2 + dwEnd.Y - b.srWindow.Top; - } - - sr.Top =3D sr.Bottom =3D toscroll; - - SetConsoleWindowInfo (h, FALSE, &sr); - - dwEnd.Y++; - SetConsoleCursorPosition (h, dwEnd); - - fillin (h); return true; } @@ -1261,8 +1234,28 @@ fhandler_console::clear_screen (cltype xc1,=20 cltype yc1, cltype xc2, cltype yc2) /* Detect special case - scroll the screen if we have a buffer in=20 order to preserve the buffer. */ - if (!con.scroll_window (h, x1, y1, x2, y2)) - con.clear_screen (h, x1, y1, x2, y2); + if (!con.clear_should_scroll (h, x1, y1, x2, y2)) + { + con.clear_screen (h, x1, y1, x2, y2); + return; + } + + int xpos, ypos; + cursor_get(&xpos, &ypos); + + for (int i =3D 0; i < con.dwWinSize.Y; i++) + { + WCHAR buf[] =3D { L'\n' }; + DWORD done; + + if (!WriteConsoleW (get_output_handle (), buf, 1, &done, 0)) + { + __seterrno (); + break; + } + } + + cursor_set(false, xpos, ypos); } void __reg3 -- Problem reports: http://cygwin.com/problems.html FAQ: http://cygwin.com/faq/ Documentation: http://cygwin.com/docs.html Unsubscribe info: http://cygwin.com/ml/#unsubscribe-simple