Add optional full_window argument to TuiWindow.write

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:

2021-05-27  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:

2021-05-27  Hannes Domani  <ssbssa@yahoo.de>

	* python.texi (TUI Windows In Python): Document "full_window"
	argument.

4 files changed, 30 insertions, 7 deletions

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 9d06a77..739e773 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,9 @@
+2021-05-27  Hannes Domani  <ssbssa@yahoo.de>
+
+	* python/py-tui.c (tui_py_window::output): Add full_window
+	argument.
+	(gdbpy_tui_write): Parse "full_window" argument.
+
 2021-05-27  Simon Marchi  <simon.marchi@polymtl.ca>
 
 	* make-init-c: Add option to reverse function calls.
diff --git a/gdb/doc/ChangeLog b/gdb/doc/ChangeLog
index 51503a7..2743079 100644
--- a/gdb/doc/ChangeLog
+++ b/gdb/doc/ChangeLog
@@ -1,5 +1,10 @@
 2021-05-27  Hannes Domani  <ssbssa@yahoo.de>
 
+	* python.texi (TUI Windows In Python): Document "full_window"
+	argument.
+
+2021-05-27  Hannes Domani  <ssbssa@yahoo.de>
+
 	* python.texi (Symbols In Python): Document gdb.SYMBOL_LOC_LABEL.
 
 2021-05-25  Hannes Domani  <ssbssa@yahoo.de>
diff --git a/gdb/doc/python.texi b/gdb/doc/python.texi
index 9127b96..23e6ac6 100644
--- a/gdb/doc/python.texi
+++ b/gdb/doc/python.texi
@@ -5959,10 +5959,14 @@ 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 22f4b0f..97e9de7 100644
--- a/gdb/python/py-tui.c
+++ b/gdb/python/py-tui.c
@@ -111,8 +111,9 @@ public:
       }
   }
 
-  /* 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;
 }