From 32788a93f23eaa683f7a88694c778cd084607754 Mon Sep 17 00:00:00 2001
From: mwenzkowski <29407878+mwenzkowski@users.noreply.github.com>
Date: Wed, 28 Oct 2020 00:02:08 +0100
Subject: [PATCH] output: evacuate sticky containers only if new output has a
 workspace

Sticky floating containers on an otherwise empty workspace can only be
evacuated if the new output has an active workspace. The noop output may
not have one and in that case we have to move the whole workspace to the
new output.
---
 include/sway/tree/workspace.h |  2 ++
 sway/tree/output.c            | 49 +++++++++++++++++++----------------
 sway/tree/workspace.c         | 13 ++++++++++
 3 files changed, 41 insertions(+), 23 deletions(-)

diff --git a/include/sway/tree/workspace.h b/include/sway/tree/workspace.h
index 1adbe68a2..fe200ec00 100644
--- a/include/sway/tree/workspace.h
+++ b/include/sway/tree/workspace.h
@@ -132,4 +132,6 @@ void workspace_get_box(struct sway_workspace *workspace, struct wlr_box *box);
 
 size_t workspace_num_tiling_views(struct sway_workspace *ws);
 
+size_t workspace_num_sticky_containers(struct sway_workspace *ws);
+
 #endif
diff --git a/sway/tree/output.c b/sway/tree/output.c
index d600c5c31..4dc22755a 100644
--- a/sway/tree/output.c
+++ b/sway/tree/output.c
@@ -152,21 +152,18 @@ void output_enable(struct sway_output *output) {
 	arrange_root();
 }
 
-static void evacuate_sticky(struct sway_workspace *old_ws,
-		struct sway_output *new_output) {
-	struct sway_workspace *new_ws = output_get_active_workspace(new_output);
-	if (!sway_assert(new_ws, "New output does not have a workspace")) {
-		return;
+static void evacuate_sticky(struct sway_container *con, void *data) {
+	if (container_is_floating(con) && con->is_sticky) {
+		struct sway_workspace *new_ws = data;
+		if (!sway_assert(new_ws, "Expected workspace to not be null")) {
+			return;
+		}
+		container_detach(con);
+		workspace_add_floating(new_ws, con);
+		container_handle_fullscreen_reparent(con);
+		container_floating_move_to_center(con);
+		ipc_event_window(con, "move");
 	}
-	while (old_ws->floating->length) {
-		struct sway_container *sticky = old_ws->floating->items[0];
-		container_detach(sticky);
-		workspace_add_floating(new_ws, sticky);
-		container_handle_fullscreen_reparent(sticky);
-		container_floating_move_to_center(sticky);
-		ipc_event_window(sticky, "move");
-	}
-	workspace_detect_urgent(new_ws);
 }
 
 static void output_evacuate(struct sway_output *output) {
@@ -195,18 +192,24 @@ static void output_evacuate(struct sway_output *output) {
 			new_output = root->noop_output;
 		}
 
-		if (workspace_is_empty(workspace)) {
-			// If floating is not empty, there are sticky containers to move
-			if (workspace->floating->length) {
-				evacuate_sticky(workspace, new_output);
-			}
-			workspace_begin_destroy(workspace);
-			continue;
-		}
-
 		struct sway_workspace *new_output_ws =
 			output_get_active_workspace(new_output);
 
+		if (workspace_is_empty(workspace)) {
+			// If the new output has an active workspace (the noop output may
+			// not have one), move all sticky containers to it
+			if (new_output_ws) {
+				workspace_for_each_container(workspace, evacuate_sticky,
+					new_output_ws);
+				workspace_detect_urgent(new_output_ws);
+			}
+
+			if (workspace_num_sticky_containers(workspace) == 0) {
+				workspace_begin_destroy(workspace);
+				continue;
+			}
+		}
+
 		workspace_output_add_priority(workspace, new_output);
 		output_add_workspace(new_output, workspace);
 		output_sort_workspaces(new_output);
diff --git a/sway/tree/workspace.c b/sway/tree/workspace.c
index 3bcba8e54..476c25681 100644
--- a/sway/tree/workspace.c
+++ b/sway/tree/workspace.c
@@ -817,3 +817,16 @@ size_t workspace_num_tiling_views(struct sway_workspace *ws) {
 	workspace_for_each_container(ws, count_tiling_views, &count);
 	return count;
 }
+
+static void count_sticky_containers(struct sway_container *con, void *data) {
+	if (container_is_floating(con) && con->is_sticky) {
+		size_t *count = data;
+		*count += 1;
+	}
+}
+
+size_t workspace_num_sticky_containers(struct sway_workspace *ws) {
+	size_t count = 0;
+	workspace_for_each_container(ws, count_sticky_containers, &count);
+	return count;
+}