svn commit: r361719 - in head/sys: dev/vt kern

[Jason A. Harmening]

Author: jah
Date: Tue Jun  2 01:21:48 2020
New Revision: 361719
URL: https://svnweb.freebsd.org/changeset/base/361719

Log:
  vt(4): reset scrollback and cursor position after clearing history buffer
  
  r361601 implemented basic support for cleaing the console history buffer.
  But after clearing the history buffer, it's not especially useful to be
  able to scroll back through that buffer, or for the cursor position to
  remain at (very likely) the bottom of the screen.
  
  PR:		224436
  Reviewed by:	emaste
  Differential Revision:	https://reviews.freebsd.org/D25079

Modified:
  head/sys/dev/vt/vt_buf.c
  head/sys/dev/vt/vt_core.c
  head/sys/kern/subr_terminal.c

Modified: head/sys/dev/vt/vt_buf.c
==============================================================================
--- head/sys/dev/vt/vt_buf.c	Tue Jun  2 01:04:49 2020	(r361718)
+++ head/sys/dev/vt/vt_buf.c	Tue Jun  2 01:21:48 2020	(r361719)
@@ -433,17 +433,22 @@ vtbuf_do_clearhistory(struct vt_buf *vb)
 	vtbuf_do_fill(vb, &rect, VTBUF_SPACE_CHAR(ch));
 }
 
-void
-vtbuf_init_early(struct vt_buf *vb)
+static void
+vtbuf_reset_scrollback(struct vt_buf *vb)
 {
-	vb->vb_flags |= VBF_CURSOR;
 	vb->vb_roffset = 0;
 	vb->vb_curroffset = 0;
 	vb->vb_mark_start.tp_row = 0;
 	vb->vb_mark_start.tp_col = 0;
 	vb->vb_mark_end.tp_row = 0;
 	vb->vb_mark_end.tp_col = 0;
+}
 
+void
+vtbuf_init_early(struct vt_buf *vb)
+{
+	vb->vb_flags |= VBF_CURSOR;
+	vtbuf_reset_scrollback(vb);
 	vtbuf_init_rows(vb);
 	vtbuf_do_clearhistory(vb);
 	vtbuf_make_undirty(vb);
@@ -477,6 +482,8 @@ vtbuf_clearhistory(struct vt_buf *vb)
 {
 	VTBUF_LOCK(vb);
 	vtbuf_do_clearhistory(vb);
+	vtbuf_reset_scrollback(vb);
+	vb->vb_flags &= ~VBF_HISTORY_FULL;
 	VTBUF_UNLOCK(vb);
 }
 

Modified: head/sys/dev/vt/vt_core.c
==============================================================================
--- head/sys/dev/vt/vt_core.c	Tue Jun  2 01:04:49 2020	(r361718)
+++ head/sys/dev/vt/vt_core.c	Tue Jun  2 01:21:48 2020	(r361719)
@@ -2332,6 +2332,16 @@ skip_thunk:
 		return (0);
 	case CONS_CLRHIST:
 		vtbuf_clearhistory(&vd->vd_curwindow->vw_buf);
+		/*
+		 * Invalidate the entire visible window; it is not guaranteed
+		 * that this operation will be immediately followed by a scroll
+		 * event, so it would otherwise be possible for prior artifacts
+		 * to remain visible.
+		 */
+		VT_LOCK(vd);
+		vd->vd_flags |= VDF_INVALID;
+		VT_UNLOCK(vd);
+		vt_resume_flush_timer(vd->vd_curwindow, 0);
 		return (0);
 	case CONS_GET:
 		/* XXX */

Modified: head/sys/kern/subr_terminal.c
==============================================================================
--- head/sys/kern/subr_terminal.c	Tue Jun  2 01:04:49 2020	(r361718)
+++ head/sys/kern/subr_terminal.c	Tue Jun  2 01:21:48 2020	(r361719)
@@ -480,6 +480,16 @@ termtty_ioctl(struct tty *tp, u_long cmd, caddr_t data
 	tty_unlock(tp);
 	error = tm->tm_class->tc_ioctl(tm, cmd, data, td);
 	tty_lock(tp);
+	if ((error == 0) && (cmd == CONS_CLRHIST)) {
+		/*
+		 * Scrollback history has been successfully cleared,
+		 * so reset the cursor position to the top left of the screen.
+		 */
+		teken_pos_t p;
+		p.tp_row = 0;
+		p.tp_col = 0;
+		teken_set_cursor(&tm->tm_emulator, &p);
+	}
 	return (error);
 }