Allow TUI windows in Python

This patch adds support for writing new TUI windows in Python.

2020-02-22  Tom Tromey  <tom@tromey.com>

	* NEWS: Add entry for gdb.register_window_type.
	* tui/tui-layout.h (window_factory): New typedef.
	(tui_register_window): Declare.
	* tui/tui-layout.c (saved_tui_windows): New global.
	(tui_apply_current_layout): Use it.
	(tui_register_window): New function.
	* python/python.c (do_start_initialization): Call
	gdbpy_initialize_tui.
	(python_GdbMethods): Add "register_window_type" function.
	* python/python-internal.h (gdbpy_register_tui_window)
	(gdbpy_initialize_tui): Declare.
	* python/py-tui.c: New file.
	* Makefile.in (SUBDIR_PYTHON_SRCS): Add py-tui.c.

gdb/doc/ChangeLog
2020-02-22  Tom Tromey  <tom@tromey.com>

	* python.texi (Python API): Add menu item.
	(TUI Windows In Python): New node.

gdb/testsuite/ChangeLog
2020-02-22  Tom Tromey  <tom@tromey.com>

	* gdb.python/tui-window.exp: New file.
	* gdb.python/tui-window.py: New file.

Change-Id: I85fbfb923a1840450a00a7dce113a05d7f048baa

2 files changed, 35 insertions, 3 deletions

diff --git a/gdb/tui/tui-layout.c b/gdb/tui/tui-layout.c
index 748a106..66c7449 100644
--- a/gdb/tui/tui-layout.c
+++ b/gdb/tui/tui-layout.c
@@ -65,6 +65,11 @@ static tui_layout_split *asm_regs_layout;
 /* See tui-data.h.  */
 std::vector<tui_win_info *> tui_windows;
 
+/* When applying a layout, this is the list of all windows that were
+   in the previous layout.  This is used to re-use windows when
+   changing a layout.  */
+static std::vector<tui_win_info *> saved_tui_windows;
+
 /* See tui-layout.h.  */
 
 void
@@ -75,10 +80,10 @@ tui_apply_current_layout ()
 
   extract_display_start_addr (&gdbarch, &addr);
 
-  std::vector<tui_win_info *> saved_windows = std::move (tui_windows);
+  saved_tui_windows = std::move (tui_windows);
   tui_windows.clear ();
 
-  for (tui_win_info *win_info : saved_windows)
+  for (tui_win_info *win_info : saved_tui_windows)
     win_info->make_visible (false);
 
   applied_layout->apply (0, 0, tui_term_width (), tui_term_height ());
@@ -94,7 +99,7 @@ tui_apply_current_layout ()
 
   /* Now delete any window that was not re-applied.  */
   tui_win_info *focus = tui_win_with_focus ();
-  for (tui_win_info *win_info : saved_windows)
+  for (tui_win_info *win_info : saved_tui_windows)
     {
       if (!win_info->is_visible ())
 	{
@@ -107,6 +112,8 @@ tui_apply_current_layout ()
   if (gdbarch == nullptr && TUI_DISASM_WIN != nullptr)
     tui_get_begin_asm_address (&gdbarch, &addr);
   tui_update_source_windows_with_addr (gdbarch, addr);
+
+  saved_tui_windows.clear ();
 }
 
 /* See tui-layout.  */
@@ -395,6 +402,21 @@ initialize_known_windows ()
 
 /* See tui-layout.h.  */
 
+void
+tui_register_window (const char *name, window_factory &&factory)
+{
+  std::string name_copy = name;
+
+  if (name_copy == "src" || name_copy == "cmd" || name_copy == "regs"
+      || name_copy == "asm" || name_copy == "status")
+    error (_("Window type \"%s\" is built-in"), name);
+
+  known_window_types->emplace (std::move (name_copy),
+			       std::move (factory));
+}
+
+/* See tui-layout.h.  */
+
 std::unique_ptr<tui_layout_base>
 tui_layout_window::clone () const
 {
diff --git a/gdb/tui/tui-layout.h b/gdb/tui/tui-layout.h
index 6607e8d..9061837 100644
--- a/gdb/tui/tui-layout.h
+++ b/gdb/tui/tui-layout.h
@@ -249,4 +249,14 @@ extern void tui_apply_current_layout ();
 extern void tui_adjust_window_height (struct tui_win_info *win,
 				      int new_height);
 
+/* The type of a function that is used to create a TUI window.  */
+
+typedef std::function<tui_gen_win_info * (const char *name)> window_factory;
+
+/* Register a new TUI window type.  NAME is the name of the window
+   type.  FACTORY is a function that can be called to instantiate the
+   window.  */
+
+extern void tui_register_window (const char *name, window_factory &&factory);
+
 #endif /* TUI_TUI_LAYOUT_H */