Files
binutils-gdb/gdb/tui/tui-wingeneral.c
Andrew Burgess 2b646bb876 gdb/tui: use wrefresh if output is not surpressed
Recent work in the TUI has improved GDB's use of the curses
wnoutrefresh and doupdate mechanism, which improves performance by
batching together updates and then doing a single set of writes to the
screen when doupdate is finally called.

The tui_batch_rendering type is a RAII class which, in its destructor,
calls doupdate to send the batched updates to the screen.

However, if there is no tui_batch_rendering active on the call stack
then any wnoutrefresh calls will remain batched but undisplayed until
the next time doupdate happens to be called.

This problem can be seen in PR gdb/32623.  When an inferior is started
the 'Starting program' message is not immediately displayed to the
user.

The 'Starting program' message originates from run_command_1 in
infcmd.c, the message is sent to the current_uiout, which will be the
TUI ui_out.  After the message is sent, ui_out::flush() is called,
here's the backtrace when that happens:

  #0  tui_file::flush (this=0x36e4ab0) at ../../src/gdb/tui/tui-file.c:42
  #1  0x0000000001004f4b in pager_file::flush (this=0x36d35f0) at ../../src/gdb/utils.c:1531
  #2  0x0000000001004f71 in gdb_flush (stream=0x36d35f0) at ../../src/gdb/utils.c:1539
  #3  0x00000000006975ab in cli_ui_out::do_flush (this=0x35a50b0) at ../../src/gdb/cli-out.c:250
  #4  0x00000000009fd1f9 in ui_out::flush (this=0x35a50b0) at ../../src/gdb/ui-out.h:263
  #5  0x00000000009f56ad in run_command_1 (args=0x0, from_tty=1, run_how=RUN_NORMAL) at ../../src/gdb/infcmd.c:449
  #6  0x00000000009f599a in run_command (args=0x0, from_tty=1) at ../../src/gdb/infcmd.c:511

And if we check out tui_file::flush (tui-file.c) we can see that this
just calls tui_win_info::refresh_window(), which in turn, just uses
wnoutrefresh to batch any pending output.

The problem is that, in the above backtrace, there is no
tui_batch_rendering active, and so there will be no doupdate call to
flush the output to the screen.

We could add a tui_batch_rendering into tui_file::flush.  And
tui_file::write.  And tui_file::puts .....

... but that all seems a bit unnecessary.  Instead, I propose that
tui_win_info::refresh_window() should be changed.  If suppress_output
is true (i.e. a tui_batch_rendering is active) then we should continue
to call wnoutrefresh().  But if suppress_output is false, meaning that
no tui_batch_rendering is in place, then we should call wrefresh(),
which immediately writes the output to the screen.

Testing but PR gdb/32623 was a little involved.  We need to 'run' the
inferior and check for the 'Starting program' message.  But DejaGNUU
can only check for the message once it knows the message should have
appeared.  But, as the bug is that output is not displayed, we don't
have any output hints that the inferior is started yet...

In the end, I have the inferior create a file in the test's output
directory.  Now DejaGNU can send the 'run' command, and wait for the
file to appear.  Once that happens, we know that the 'Starting
program' message should have appeared.

Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=32623

Approved-By: Tom Tromey <tom@tromey.com>
2025-02-08 19:49:07 +00:00

178 lines
4.1 KiB
C

/* General window behavior.
Copyright (C) 1998-2024 Free Software Foundation, Inc.
Contributed by Hewlett-Packard Company.
This file is part of GDB.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>. */
#include "tui/tui-data.h"
#include "tui/tui-io.h"
#include "tui/tui-wingeneral.h"
#include "tui/tui-win.h"
#include "cli/cli-style.h"
#include "gdb_curses.h"
/* This is true when there is a live instance of tui_batch_rendering.
The outermost tui_batch_rendering will cause a flush to the
screen. */
static bool suppress_output;
/* See tui-data.h. */
tui_batch_rendering::tui_batch_rendering ()
: m_saved_suppress (suppress_output)
{
suppress_output = true;
}
/* See tui-data.h. */
tui_batch_rendering::~tui_batch_rendering ()
{
suppress_output = m_saved_suppress;
if (!suppress_output)
doupdate ();
}
/* See tui-data.h. */
void
tui_win_info::refresh_window ()
{
if (handle != NULL)
{
if (suppress_output)
wnoutrefresh (handle.get ());
else
wrefresh (handle.get ());
}
}
/* Draw a border around the window. */
static void
box_win (struct tui_win_info *win_info,
bool highlight_flag)
{
WINDOW *win;
int attrs;
win = win_info->handle.get ();
if (highlight_flag)
attrs = tui_active_border_attrs;
else
attrs = tui_border_attrs;
/* tui_apply_style resets the style entirely, so be sure to call it
before applying ATTRS. */
if (cli_styling)
tui_apply_style (win, (highlight_flag
? tui_active_border_style.style ()
: tui_border_style.style ()));
wattron (win, attrs);
wborder (win, tui_border_vline, tui_border_vline,
tui_border_hline, tui_border_hline,
tui_border_ulcorner, tui_border_urcorner,
tui_border_llcorner, tui_border_lrcorner);
if (!win_info->title ().empty ())
{
/* Emit "+-TITLE-+" -- so 2 characters on the right and 2 on
the left. */
int max_len = win_info->width - win_info->box_size () - 2;
if (win_info->title ().size () <= max_len)
mvwaddstr (win, 0, 2, win_info->title ().c_str ());
else
{
std::string truncated
= "..." + win_info->title ().substr (win_info->title ().size ()
- max_len + 3);
mvwaddstr (win, 0, 2, truncated.c_str ());
}
}
wattroff (win, attrs);
tui_apply_style (win, ui_file_style ());
}
void
tui_unhighlight_win (struct tui_win_info *win_info)
{
if (win_info != NULL
&& win_info->can_box ()
&& win_info->handle != NULL)
{
box_win (win_info, false);
win_info->refresh_window ();
win_info->set_highlight (false);
}
}
void
tui_highlight_win (struct tui_win_info *win_info)
{
if (win_info != NULL
&& win_info->can_box ()
&& win_info->handle != NULL)
{
box_win (win_info, true);
win_info->refresh_window ();
win_info->set_highlight (true);
}
}
void
tui_win_info::check_and_display_highlight_if_needed ()
{
if (can_box ())
{
if (is_highlighted)
tui_highlight_win (this);
else
tui_unhighlight_win (this);
}
}
void
tui_win_info::make_window ()
{
handle.reset (newwin (height, width, y, x));
if (handle != NULL)
{
scrollok (handle.get (), TRUE);
if (can_box ())
box_win (this, false);
}
}
/* We can't really make windows visible, or invisible. So we have to
delete the entire window when making it invisible, and create it
again when making it visible. */
void
tui_win_info::make_visible (bool visible)
{
if (is_visible () == visible)
return;
if (visible)
make_window ();
else
handle.reset (nullptr);
}