monitor-manager: Add config relationships and use it for orientation events

When we get an orientation event we don't care about keeping track of the
configuration changes, but actually we can consider the new configuration
just a variant of the previous one, adapted to floating device hardware
events, so we only want to apply it if possible, but we don't want to keep
a record of it for reverting capabilities.

Doing that would in fact, break the ability of reverting back to an actual
temporary or persistent configuration.
For example when device orientation events happen while we're waiting for
an user resolution change confirmation, we would save our new rotated
configuration in the history, making then impossible to revert back to
the original persistent one.

So in such case, don't keep track of those configurations in the history,
but only keep track of the last one as current, checking whether the
new current is child or sibling of the previously one.

Fixes: https://gitlab.gnome.org/GNOME/mutter/-/issues/1221
Related to: https://gitlab.gnome.org/GNOME/mutter/-/issues/646

Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1233>

src/backends/meta-monitor-config-manager.c

@@ -1038,6 +1038,7 @@ create_for_builtin_display_rotation (MetaMonitorConfigManager *config_manager,
   MetaMonitorManager *monitor_manager = config_manager->monitor_manager;
   MetaLogicalMonitorConfig *logical_monitor_config;
   MetaLogicalMonitorConfig *current_logical_monitor_config;
+  MetaMonitorsConfig *config;
   GList *logical_monitor_configs, *current_configs;
   MetaLogicalMonitorLayoutMode layout_mode;
 
@@ -1085,10 +1086,13 @@ create_for_builtin_display_rotation (MetaMonitorConfigManager *config_manager,
     }
 
   layout_mode = base_config->layout_mode;
-  return meta_monitors_config_new (monitor_manager,
-                                   logical_monitor_configs,
-                                   layout_mode,
-                                   META_MONITORS_CONFIG_FLAG_NONE);
+  config = meta_monitors_config_new (monitor_manager,
+                                     logical_monitor_configs,
+                                     layout_mode,
+                                     META_MONITORS_CONFIG_FLAG_NONE);
+  meta_monitors_config_set_parent_config (config, base_config);
+
+  return config;
 }
 
 MetaMonitorsConfig *
@@ -1121,6 +1125,9 @@ meta_monitor_config_manager_create_for_builtin_orientation (MetaMonitorConfigMan
 MetaMonitorsConfig *
 meta_monitor_config_manager_create_for_rotate_monitor (MetaMonitorConfigManager *config_manager)
 {
+  if (!config_manager->current_config)
+    return NULL;
+
   return create_for_builtin_display_rotation (config_manager,
                                               config_manager->current_config,
                                               TRUE,
@@ -1319,11 +1326,37 @@ meta_monitor_config_manager_create_for_switch_config (MetaMonitorConfigManager
   return config;
 }
 
+static MetaMonitorsConfig *
+get_root_config (MetaMonitorsConfig *config)
+{
+  if (!config->parent_config)
+    return config;
+
+  return get_root_config (config->parent_config);
+}
+
+static gboolean
+has_same_root_config (MetaMonitorsConfig *config_a,
+                      MetaMonitorsConfig *config_b)
+{
+  return get_root_config (config_a) == get_root_config (config_b);
+}
+
 void
 meta_monitor_config_manager_set_current (MetaMonitorConfigManager *config_manager,
                                          MetaMonitorsConfig       *config)
 {
-  if (config_manager->current_config)
+  MetaMonitorsConfig *current_config = config_manager->current_config;
+  gboolean overrides_current = FALSE;
+
+  if (config && current_config &&
+      has_same_root_config (config, current_config))
+    {
+      overrides_current = meta_monitors_config_key_equal (config->key,
+                                                          current_config->key);
+    }
+
+  if (current_config && !overrides_current)
     {
       g_queue_push_head (&config_manager->config_history,
                          g_object_ref (config_manager->current_config));
@@ -1522,6 +1555,16 @@ meta_monitors_config_set_switch_config (MetaMonitorsConfig          *config,
   config->switch_config = switch_config;
 }
 
+void
+meta_monitors_config_set_parent_config (MetaMonitorsConfig *config,
+                                        MetaMonitorsConfig *parent_config)
+{
+  g_assert (config != parent_config);
+  g_assert (!parent_config || parent_config->parent_config != config);
+
+  g_set_object (&config->parent_config, parent_config);
+}
+
 MetaMonitorsConfig *
 meta_monitors_config_new_full (GList                        *logical_monitor_configs,
                                GList                        *disabled_monitor_specs,
@@ -1583,6 +1626,7 @@ meta_monitors_config_finalize (GObject *object)
 {
   MetaMonitorsConfig *config = META_MONITORS_CONFIG (object);
 
+  g_clear_object (&config->parent_config);
   meta_monitors_config_key_free (config->key);
   g_list_free_full (config->logical_monitor_configs,
                     (GDestroyNotify) meta_logical_monitor_config_free);

src/backends/meta-monitor-config-manager.h

@@ -62,6 +62,7 @@ struct _MetaMonitorsConfig
 {
   GObject parent;
 
+  MetaMonitorsConfig *parent_config;
   MetaMonitorsConfigKey *key;
   GList *logical_monitor_configs;
 
@@ -157,6 +158,10 @@ META_EXPORT_TEST
 void meta_monitors_config_set_switch_config (MetaMonitorsConfig          *config,
                                              MetaMonitorSwitchConfigType  switch_config);
 
+META_EXPORT_TEST
+void meta_monitors_config_set_parent_config (MetaMonitorsConfig *config,
+                                             MetaMonitorsConfig *parent_config);
+
 META_EXPORT_TEST
 unsigned int meta_monitors_config_key_hash (gconstpointer config_key);
 

src/backends/meta-monitor-manager.c

@@ -773,6 +773,18 @@ meta_monitor_manager_ensure_configured (MetaMonitorManager *manager)
   config = meta_monitor_config_manager_get_previous (manager->config_manager);
   if (config)
     {
+      g_autoptr (MetaMonitorsConfig) oriented_config = NULL;
+
+      if (manager->panel_orientation_managed)
+        {
+          oriented_config =
+            meta_monitor_config_manager_create_for_builtin_orientation (
+              manager->config_manager, config);
+
+          if (oriented_config)
+            config = oriented_config;
+        }
+
       config = g_object_ref (config);
 
       if (meta_monitor_manager_is_config_complete (manager, config))
@@ -891,6 +903,9 @@ handle_orientation_change (MetaOrientationManager *orientation_manager,
 
   current_config =
     meta_monitor_config_manager_get_current (manager->config_manager);
+  if (!current_config)
+    return;
+
   config =
     meta_monitor_config_manager_create_for_orientation (manager->config_manager,
                                                         current_config,

src/tests/monitor-unit-tests.c

@@ -302,6 +302,107 @@ meta_test_monitor_config_store_set_current_on_empty (void)
   g_assert_null (meta_monitor_config_manager_pop_previous (config_manager));
 }
 
+static void
+meta_test_monitor_config_store_set_current_with_parent_on_empty (void)
+{
+  g_autoptr (MetaMonitorsConfig) parent_config = NULL;
+  g_autoptr (MetaMonitorsConfig) child_config1 = NULL;
+  g_autoptr (MetaMonitorsConfig) child_config2 = NULL;
+  g_autoptr (MetaMonitorsConfig) child_config3 = NULL;
+  g_autoptr (MetaMonitorsConfig) linear_config = NULL;
+  g_autoptr (MetaMonitorsConfig) fallback_config = NULL;
+  MetaBackend *backend = meta_get_backend ();
+  MetaMonitorManager *monitor_manager =
+    meta_backend_get_monitor_manager (backend);
+  MetaMonitorConfigManager *config_manager = monitor_manager->config_manager;
+  MetaMonitorsConfig *old_current;
+
+  parent_config = meta_monitor_config_manager_create_linear (config_manager);
+
+  child_config1 = meta_monitor_config_manager_create_linear (config_manager);
+  meta_monitors_config_set_parent_config (child_config1, parent_config);
+  old_current = meta_monitor_config_manager_get_current (config_manager);
+
+  g_assert_null (old_current);
+  g_assert_nonnull (child_config1);
+
+  meta_monitor_config_manager_set_current (config_manager, child_config1);
+
+  g_assert (meta_monitor_config_manager_get_current (config_manager) ==
+            child_config1);
+  g_assert (meta_monitor_config_manager_get_current (config_manager) !=
+            old_current);
+  g_assert_null (meta_monitor_config_manager_get_previous (config_manager));
+  g_assert_null (meta_monitor_config_manager_pop_previous (config_manager));
+
+  child_config2 = meta_monitor_config_manager_create_linear (config_manager);
+  meta_monitors_config_set_parent_config (child_config2, parent_config);
+  g_assert (child_config2->parent_config == parent_config);
+
+  old_current = meta_monitor_config_manager_get_current (config_manager);
+  g_assert_nonnull (old_current->parent_config);
+  meta_monitor_config_manager_set_current (config_manager, child_config2);
+
+  g_assert (meta_monitor_config_manager_get_current (config_manager) ==
+            child_config2);
+  g_assert (meta_monitor_config_manager_get_current (config_manager) !=
+            old_current);
+  g_assert_null (meta_monitor_config_manager_get_previous (config_manager));
+  g_assert_null (meta_monitor_config_manager_pop_previous (config_manager));
+
+  child_config3 = meta_monitor_config_manager_create_linear (config_manager);
+  meta_monitors_config_set_parent_config (child_config3, child_config2);
+
+  old_current = meta_monitor_config_manager_get_current (config_manager);
+  g_assert_nonnull (old_current->parent_config);
+  meta_monitor_config_manager_set_current (config_manager, child_config3);
+
+  g_assert (meta_monitor_config_manager_get_current (config_manager) ==
+            child_config3);
+  g_assert (meta_monitor_config_manager_get_current (config_manager) !=
+            old_current);
+  g_assert_null (meta_monitor_config_manager_get_previous (config_manager));
+  g_assert_null (meta_monitor_config_manager_pop_previous (config_manager));
+
+  linear_config = meta_monitor_config_manager_create_linear (config_manager);
+  g_assert_null (linear_config->parent_config);
+
+  old_current = meta_monitor_config_manager_get_current (config_manager);
+  g_assert_nonnull (old_current->parent_config);
+  meta_monitor_config_manager_set_current (config_manager, linear_config);
+
+  g_assert (meta_monitor_config_manager_get_current (config_manager) ==
+            linear_config);
+  g_assert (meta_monitor_config_manager_get_current (config_manager) !=
+            old_current);
+  g_assert (meta_monitor_config_manager_get_previous (config_manager) ==
+            child_config3);
+
+  fallback_config =
+    meta_monitor_config_manager_create_fallback (config_manager);
+  g_assert_null (fallback_config->parent_config);
+
+  old_current = meta_monitor_config_manager_get_current (config_manager);
+  g_assert_null (old_current->parent_config);
+  meta_monitor_config_manager_set_current (config_manager, fallback_config);
+
+  g_assert (meta_monitor_config_manager_get_current (config_manager) ==
+            fallback_config);
+  g_assert (meta_monitor_config_manager_get_current (config_manager) !=
+            old_current);
+
+  g_assert (meta_monitor_config_manager_get_previous (config_manager) ==
+            linear_config);
+  g_assert (meta_monitor_config_manager_pop_previous (config_manager) ==
+            linear_config);
+  g_assert (meta_monitor_config_manager_get_previous (config_manager) ==
+            child_config3);
+  g_assert (meta_monitor_config_manager_pop_previous (config_manager) ==
+            child_config3);
+  g_assert_null (meta_monitor_config_manager_get_previous (config_manager));
+  g_assert_null (meta_monitor_config_manager_pop_previous (config_manager));
+}
+
 static void
 meta_test_monitor_config_store_set_current (void)
 {
@@ -340,6 +441,88 @@ meta_test_monitor_config_store_set_current (void)
   g_assert_null (meta_monitor_config_manager_pop_previous (config_manager));
 }
 
+static void
+meta_test_monitor_config_store_set_current_with_parent (void)
+{
+  g_autoptr (MetaMonitorsConfig) child_config = NULL;
+  g_autoptr (MetaMonitorsConfig) other_child = NULL;
+  g_autoptr (MetaMonitorsConfig) linear_config = NULL;
+  g_autoptr (MetaMonitorsConfig) fallback_config = NULL;
+  MetaBackend *backend = meta_get_backend ();
+  MetaMonitorManager *monitor_manager =
+    meta_backend_get_monitor_manager (backend);
+  MetaMonitorConfigManager *config_manager = monitor_manager->config_manager;
+  MetaMonitorsConfig *old_current;
+
+  linear_config = meta_monitor_config_manager_create_linear (config_manager);
+  g_assert_null (linear_config->parent_config);
+
+  old_current = meta_monitor_config_manager_get_current (config_manager);
+  g_assert_null (old_current);
+  meta_monitor_config_manager_set_current (config_manager, linear_config);
+
+  g_assert (meta_monitor_config_manager_get_current (config_manager) ==
+            linear_config);
+  g_assert (meta_monitor_config_manager_get_current (config_manager) !=
+            old_current);
+  g_assert_null (meta_monitor_config_manager_get_previous (config_manager));
+  g_assert_null (meta_monitor_config_manager_pop_previous (config_manager));
+
+  fallback_config = meta_monitor_config_manager_create_fallback (config_manager);
+  g_assert_nonnull (fallback_config);
+  g_assert_null (fallback_config->parent_config);
+
+  old_current = meta_monitor_config_manager_get_current (config_manager);
+  g_assert_nonnull (old_current);
+  g_assert_null (old_current->parent_config);
+  meta_monitor_config_manager_set_current (config_manager, fallback_config);
+
+  g_assert (meta_monitor_config_manager_get_current (config_manager) ==
+            fallback_config);
+  g_assert (meta_monitor_config_manager_get_current (config_manager) !=
+            old_current);
+  g_assert (meta_monitor_config_manager_get_previous (config_manager) ==
+            old_current);
+
+  child_config = meta_monitor_config_manager_create_linear (config_manager);
+  old_current = meta_monitor_config_manager_get_current (config_manager);
+  meta_monitors_config_set_parent_config (child_config, old_current);
+
+  g_assert_nonnull (child_config);
+  g_assert_nonnull (old_current);
+  g_assert (old_current == fallback_config);
+  g_assert_null (old_current->parent_config);
+
+  meta_monitor_config_manager_set_current (config_manager, child_config);
+
+  g_assert (meta_monitor_config_manager_get_current (config_manager) ==
+            child_config);
+  g_assert (meta_monitor_config_manager_get_current (config_manager) !=
+            old_current);
+  g_assert (meta_monitor_config_manager_get_previous (config_manager) ==
+            linear_config);
+
+  other_child = meta_monitor_config_manager_create_linear (config_manager);
+  meta_monitors_config_set_parent_config (other_child, old_current);
+
+  old_current = meta_monitor_config_manager_get_current (config_manager);
+  g_assert_nonnull (old_current->parent_config);
+  g_assert (old_current == child_config);
+  meta_monitor_config_manager_set_current (config_manager, other_child);
+
+  g_assert (meta_monitor_config_manager_get_current (config_manager) ==
+            other_child);
+  g_assert (meta_monitor_config_manager_get_current (config_manager) !=
+            old_current);
+  g_assert (meta_monitor_config_manager_get_previous (config_manager) ==
+            linear_config);
+  g_assert (meta_monitor_config_manager_pop_previous (config_manager) ==
+            linear_config);
+
+  g_assert_null (meta_monitor_config_manager_get_previous (config_manager));
+  g_assert_null (meta_monitor_config_manager_pop_previous (config_manager));
+}
+
 static void
 meta_test_monitor_config_store_set_current_max_size (void)
 {
@@ -7044,8 +7227,12 @@ init_monitor_tests (void)
 
   add_monitor_test ("/backends/monitor/config-store/set_current-on-empty",
                     meta_test_monitor_config_store_set_current_on_empty);
+  add_monitor_test ("/backends/monitor/config-store/set_current-with-parent-on-empty",
+                    meta_test_monitor_config_store_set_current_with_parent_on_empty);
   add_monitor_test ("/backends/monitor/config-store/set_current",
                     meta_test_monitor_config_store_set_current);
+  add_monitor_test ("/backends/monitor/config-store/set_current-with-parent",
+                    meta_test_monitor_config_store_set_current_with_parent);
   add_monitor_test ("/backends/monitor/config-store/set_current-max-size",
                     meta_test_monitor_config_store_set_current_max_size);
   add_monitor_test ("/backends/monitor/config-store/set_current-null",