[PATCHv2,1/3] gdb/python: allow Python TUI windows to be replaced
Commit Message
The documentation for gdb.register_window_type says:
"... It's an error to try to replace one of the built-in windows,
but other window types can be replaced. ..."
I take this to mean that if I imported a Python script like this:
gdb.register_window_type('my_window', FactoryFunction)
Then GDB would have a new TUI window 'my_window', which could be
created by calling FactoryFunction(). If I then, in the same GDB
session imported a script which included:
gdb.register_window_type('my_window', UpdatedFactoryFunction)
Then GDB would replace the old 'my_window' factory with my new one,
GDB would now call UpdatedFactoryFunction().
This is pretty useful in practice, as it allows users to iterate on
their window implementation within a single GDB session.
However, right now, this is not how GDB operates. The second call to
register_window_type is basically ignored and the old window factory
is retained.
This is because in tui_register_window (tui/tui-layout.c) we use
std::unordered_map::emplace to insert the new factory function, and
emplace doesn't replace an existing element in an unordered_map.
In this commit, before the emplace call, I now search for an already
existing element, and delete any matching element from the map, the
emplace call will then add the new factory function.
---
.../gdb.python/tui-window-factory.exp | 73 +++++++++++++++++++
.../gdb.python/tui-window-factory.py | 48 ++++++++++++
gdb/tui/tui-layout.c | 8 ++
3 files changed, 129 insertions(+)
create mode 100644 gdb/testsuite/gdb.python/tui-window-factory.exp
create mode 100644 gdb/testsuite/gdb.python/tui-window-factory.py
new file mode 100644
@@ -0,0 +1,73 @@
+# Copyright (C) 2023 Free Software Foundation, Inc.
+#
+# 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/>.
+
+# Test that GDB correctly deallocates the window factory object (a)
+# when a window factory is replaced, and (b) during GDB shutdown.
+#
+# This test also ensures that when a new window is registered (via the
+# Python API) with the same name as an existing window, then the
+# previous window is replaced.
+
+load_lib gdb-python.exp
+
+tuiterm_env
+
+clean_restart
+
+require allow_tui_tests allow_python_tests
+
+set pyfile [gdb_remote_download host \
+ ${srcdir}/${subdir}/${gdb_test_file_name}.py]
+
+Term::clean_restart 24 80
+Term::prepare_for_tui
+
+gdb_test "source ${pyfile}" "Python script imported" \
+ "import python scripts"
+
+gdb_test "python register_window_factory('msg_1')" \
+ "Entering TestWindowFactory\\.__init__: msg_1"
+
+gdb_test "python register_window_factory('msg_2')" \
+ [multi_line \
+ "Entering TestWindowFactory\\.__init__: msg_2" \
+ "Entering TestWindowFactory\\.__del__: msg_1"]
+
+gdb_test_no_output "tui new-layout test test_window 1 cmd 1 status 1"
+
+# Load the custom window layout and ensure that the correct window
+# factory was used.
+with_test_prefix "msg_2" {
+ Term::command_no_prompt_prefix "layout test"
+ Term::check_box_contents "check test_window box" 0 0 80 15 \
+ "TestWindow \\(msg_2\\)"
+}
+
+# Replace the existing window factory with a new one, then switch
+# layouts so that GDB recreates the window, and check that the new
+# window factory was used.
+with_test_prefix "msg_3" {
+ Term::command "python register_window_factory('msg_3')"
+ Term::check_region_contents "check for python output" \
+ 0 18 80 2 \
+ [multi_line \
+ "Entering TestWindowFactory.__init__: msg_3\\s+" \
+ "Entering TestWindowFactory.__del__: msg_2"]
+ Term::command "layout src"
+ Term::command "layout test"
+
+ Term::check_box_contents "check test_window box" 0 0 80 15 \
+ "TestWindow \\(msg_3\\)"
+}
new file mode 100644
@@ -0,0 +1,48 @@
+# Copyright (C) 2023 Free Software Foundation, Inc.
+
+# 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/>.
+
+
+class TestWindow:
+ def __init__(self, tui_win, msg):
+ self.msg = msg
+ self.tui_win = tui_win
+ print("Entering TestWindow.__init__: %s" % self.msg)
+
+ def render(self):
+ self.tui_win.erase()
+ self.tui_win.write("TestWindow (%s)" % self.msg)
+
+ def __del__(self):
+ print("Entering TestWindow.__del__: %s" % self.msg)
+
+
+class TestWindowFactory:
+ def __init__(self, msg):
+ self.msg = msg
+ print("Entering TestWindowFactory.__init__: %s" % self.msg)
+
+ def __call__(self, tui_win):
+ print("Entering TestWindowFactory.__call__: %s" % self.msg)
+ return TestWindow(tui_win, self.msg)
+
+ def __del__(self):
+ print("Entering TestWindowFactory.__del__: %s" % self.msg)
+
+
+def register_window_factory(msg):
+ gdb.register_window_type("test_window", TestWindowFactory(msg))
+
+
+print("Python script imported")
@@ -418,6 +418,14 @@ tui_register_window (const char *name, window_factory &&factory)
if (!ISALPHA (name_copy[0]))
error (_("window name must start with a letter, not '%c'"), name_copy[0]);
+ /* We already check above for all the builtin window names. If we get
+ this far then NAME must be a user defined window. Remove any existing
+ factory and replace it with this new version. */
+
+ auto iter = known_window_types->find (name);
+ if (iter != known_window_types->end ())
+ known_window_types->erase (iter);
+
known_window_types->emplace (std::move (name_copy),
std::move (factory));
}