From 08bb689ae7b22c38edd9188c5a1ed05a680030ef Mon Sep 17 00:00:00 2001
From: Norman Feske <norman.feske@genode-labs.com>
Date: Tue, 27 Nov 2018 14:04:20 +0100
Subject: [PATCH] window layouter: bring unknown windows to front

This patch improves the handing of new appearing windows for which only
a wildcard assignment - but no exact assignment - rule exists. In the
prior version, an interactively raised window would stay in front of
such a window, which is unintuitive. The new version applies the
to-front mechanism to unknown new windows. For known new windows (with
an exact assignment rule) their original stacking position is preserved.
---
 repos/gems/src/app/window_layouter/assign.h   | 14 +++++++++-
 .../src/app/window_layouter/assign_list.h     |  8 ++++++
 repos/gems/src/app/window_layouter/main.cc    | 28 ++++++++++++++-----
 3 files changed, 42 insertions(+), 8 deletions(-)

diff --git a/repos/gems/src/app/window_layouter/assign.h b/repos/gems/src/app/window_layouter/assign.h
index c70c02eb2a..5160f3b07f 100644
--- a/repos/gems/src/app/window_layouter/assign.h
+++ b/repos/gems/src/app/window_layouter/assign.h
@@ -148,7 +148,7 @@ class Window_layouter::Assign : public List_model<Assign>::Element
 		Target::Name target_name() const { return _target_name; }
 
 		/**
-		 * Generate <assign> nodes of windows captured via wildcard
+		 * Used to generate <assign> nodes of windows captured via wildcard
 		 */
 		template <typename FN>
 		void for_each_wildcard_member(FN const &fn) const
@@ -160,6 +160,18 @@ class Window_layouter::Assign : public List_model<Assign>::Element
 			_members.for_each([&] (Assign::Member const &member) { fn(member); });
 		}
 
+		/**
+		 * Used to bring wildcard-matching windows to front
+		 */
+		template <typename FN>
+		void for_each_wildcard_member(FN const &fn)
+		{
+			if (_label.valid())
+				return;
+
+			_members.for_each([&] (Assign::Member &member) { fn(member); });
+		}
+
 		bool floating() const { return _pos_defined; }
 
 		bool wildcard() const { return !_label.valid(); }
diff --git a/repos/gems/src/app/window_layouter/assign_list.h b/repos/gems/src/app/window_layouter/assign_list.h
index 63fa84bbae..4bc28af458 100644
--- a/repos/gems/src/app/window_layouter/assign_list.h
+++ b/repos/gems/src/app/window_layouter/assign_list.h
@@ -90,6 +90,14 @@ class Window_layouter::Assign_list : Noncopyable
 					fn(assign, member); }); });
 		}
 
+		template <typename FN>
+		void for_each_wildcard_assigned_window(FN const &fn)
+		{
+			_assignments.for_each([&] (Assign &assign) {
+				assign.for_each_wildcard_member([&] (Assign::Member &member) {
+					fn(member.window); }); });
+		}
+
 		/**
 		 * Return true if any window is assigned via a wildcard
 		 *
diff --git a/repos/gems/src/app/window_layouter/main.cc b/repos/gems/src/app/window_layouter/main.cc
index 6474c9c1b0..700f0ef111 100644
--- a/repos/gems/src/app/window_layouter/main.cc
+++ b/repos/gems/src/app/window_layouter/main.cc
@@ -64,6 +64,22 @@ struct Window_layouter::Main : Operations,
 
 	Target_list _target_list { _heap };
 
+	/**
+	 * Bring window to front, return true if the stacking order changed
+	 */
+	bool _to_front(Window &window)
+	{
+		bool stacking_order_changed = false;
+
+		if (window.to_front_cnt() != _to_front_cnt) {
+			_to_front_cnt++;
+			window.to_front_cnt(_to_front_cnt);
+			stacking_order_changed = true;
+		};
+
+		return stacking_order_changed;
+	}
+
 	void _update_window_layout()
 	{
 		_window_list.dissolve_windows_from_assignments();
@@ -95,6 +111,10 @@ struct Window_layouter::Main : Operations,
 			});
 		});
 
+		/* bring new windows that solely match a wildcard assignment to the front */
+		_assign_list.for_each_wildcard_assigned_window([&] (Window &window) {
+			_to_front(window); });
+
 		_gen_window_layout();
 
 		if (_assign_list.matching_wildcards())
@@ -147,13 +167,7 @@ struct Window_layouter::Main : Operations,
 		bool stacking_order_changed = false;
 
 		_window_list.with_window(id, [&] (Window &window) {
-
-			if (window.to_front_cnt() != _to_front_cnt) {
-				_to_front_cnt++;
-				window.to_front_cnt(_to_front_cnt);
-				stacking_order_changed = true;
-			};
-		});
+			stacking_order_changed = _to_front(window); });
 
 		if (stacking_order_changed)
 			_gen_rules();