[PATCHv2 2/2] Add optional full_window argument to TuiWindow.write

[Hannes Domani <ssbssa@yahoo.de>]

To prevent flickering when first calling erase, then write, this new
argument indicates that the passed string contains the full contents of
the window.  This fills every unused cell of the window with a space, so
it's not necessary to call erase beforehand.

gdb/ChangeLog:

2021-05-21  Hannes Domani  <ssbssa@yahoo.de>

	* python/py-tui.c (tui_py_window::output): Add full_window
	argument.
	(gdbpy_tui_write): Parse "full_window" argument.

gdb/doc/ChangeLog:

2021-05-21  Hannes Domani  <ssbssa@yahoo.de>

	* python.texi (TUI Windows In Python): Document "full_window"
	argument.
---
v2:
- Add ChangeLog.
- Describe full_window argument in ouput function comment.
---
 gdb/doc/python.texi |  6 +++++-
 gdb/python/py-tui.c | 20 ++++++++++++++------
 2 files changed, 19 insertions(+), 7 deletions(-)

diff --git a/gdb/doc/python.texi b/gdb/doc/python.texi
index fa9aa703519..aad480b2a5c 100644
--- a/gdb/doc/python.texi
+++ b/gdb/doc/python.texi
@@ -5961,10 +5961,14 @@ displayed above the window.  This attribute can be modified.
 Remove all the contents of the window.
 @end defun
 
-@defun TuiWindow.write (@var{string})
+@defun TuiWindow.write (@var{string} @r{[}, @var{full_window}@r{]})
 Write @var{string} to the window.  @var{string} can contain ANSI
 terminal escape styling sequences; @value{GDBN} will translate these
 as appropriate for the terminal.
+
+If the @var{full_window} parameter is @code{True}, then @var{string}
+contains the full contents of the window.  This is similar to calling
+@code{erase} before @code{write}, but avoids the flickering.
 @end defun
 
 The factory function that you supply should return an object
diff --git a/gdb/python/py-tui.c b/gdb/python/py-tui.c
index 22f4b0ffd43..97e9de7a00c 100644
--- a/gdb/python/py-tui.c
+++ b/gdb/python/py-tui.c
@@ -111,8 +111,9 @@ class tui_py_window : public tui_win_info
       }
   }
 
-  /* Write STR to the window.  */
-  void output (const char *str);
+  /* Write STR to the window.  FULL_WINDOW is true to erase the window
+     contents beforehand.  */
+  void output (const char *str, bool full_window);
 
   /* A helper function to compute the viewport width.  */
   int viewport_width () const
@@ -229,12 +230,18 @@ tui_py_window::do_scroll_vertical (int num_to_scroll)
 }
 
 void
-tui_py_window::output (const char *text)
+tui_py_window::output (const char *text, bool full_window)
 {
   if (m_inner_window != nullptr)
     {
+      if (full_window)
+	werase (m_inner_window.get ());
+
       tui_puts (text, m_inner_window.get ());
-      tui_wrefresh (m_inner_window.get ());
+      if (full_window)
+	check_and_display_highlight_if_needed ();
+      else
+	tui_wrefresh (m_inner_window.get ());
     }
 }
 
@@ -405,13 +412,14 @@ gdbpy_tui_write (PyObject *self, PyObject *args)
 {
   gdbpy_tui_window *win = (gdbpy_tui_window *) self;
   const char *text;
+  int full_window = 0;
 
-  if (!PyArg_ParseTuple (args, "s", &text))
+  if (!PyArg_ParseTuple (args, "s|i", &text, &full_window))
     return nullptr;
 
   REQUIRE_WINDOW (win);
 
-  win->window->output (text);
+  win->window->output (text, full_window);
 
   Py_RETURN_NONE;
 }
-- 
2.31.1