Refactor destroy functions and save workspaces when there's no outputs

This changes the destroy functions to the following:

* output_begin_destroy
* output_destroy
* workspace_begin_destroy
* workspace_destroy
* container_begin_destroy
* container_destroy
* view_begin_destroy
* view_destroy

The terminology was `destroy` and `free`, and it has been changed to
`begin_destroy` and `destroy` respectively.

When the last output is disconnected, its workspaces will now be stashed
in the root. Upon connection of a new output they will be restored.

There is a new function `workspace_consider_destroy` which decides
whether the given workspace should be destroyed or not (ie. empty and
not visible).

Calling container_begin_destroy will no longer automatically reap the
parents. In some places we want to reap the parents and in some we
don't, so this is left to the caller.

container_reap_empty_recursive and container_reap_empty have been
combined into one function and it will recurse up the tree.

include/sway/output.h

@@ -39,6 +39,12 @@ struct sway_output {
 	} events;
 };
 
+struct sway_container *output_create(struct sway_output *sway_output);
+
+void output_destroy(struct sway_container *output);
+
+void output_begin_destroy(struct sway_container *output);
+
 typedef void (*sway_surface_iterator_func_t)(struct sway_output *output,
 	struct wlr_surface *surface, struct wlr_box *box, float rotation,
 	void *user_data);

include/sway/tree/container.h

@@ -176,27 +176,6 @@ struct sway_container *container_create(enum sway_container_type type);
 
 const char *container_type_to_str(enum sway_container_type type);
 
-struct sway_container *output_create(struct sway_output *sway_output);
-
-/**
- * Create a new container container. A container container can be a a child of
- * a workspace container or another container container.
- */
-struct sway_container *container_container_create();
-
-/**
- * Create a new output. Outputs are children of the root container and have no
- * order in the tree structure.
- */
-struct sway_container *output_create(struct sway_output *sway_output);
-
-/**
- * Create a new workspace container. Workspaces are children of an output
- * container and are ordered alphabetically by name.
- */
-struct sway_container *workspace_create(struct sway_container *output,
-		const char *name);
-
 /*
  * Create a new view container. A view can be a child of a workspace container
  * or a container container and are rendered in the order and structure of
@@ -205,9 +184,9 @@ struct sway_container *workspace_create(struct sway_container *output,
 struct sway_container *container_view_create(
 		struct sway_container *sibling, struct sway_view *sway_view);
 
-void container_free(struct sway_container *cont);
+void container_destroy(struct sway_container *con);
 
-struct sway_container *container_destroy(struct sway_container *container);
+void container_begin_destroy(struct sway_container *con);
 
 struct sway_container *container_close(struct sway_container *container);
 
@@ -255,10 +234,7 @@ void container_update_textures_recursive(struct sway_container *con);
 
 void container_damage_whole(struct sway_container *container);
 
-bool container_reap_empty(struct sway_container *con);
+struct sway_container *container_reap_empty(struct sway_container *con);
-
-struct sway_container *container_reap_empty_recursive(
-		struct sway_container *con);
 
 struct sway_container *container_flatten(struct sway_container *container);
 

include/sway/tree/root.h

@@ -24,6 +24,7 @@ struct sway_root {
 	struct wl_list outputs; // sway_output::link
 
 	list_t *scratchpad; // struct sway_container
+	list_t *saved_workspaces; // For when there's no connected outputs
 
 	struct {
 		struct wl_signal new_container;

include/sway/tree/view.h

@@ -284,10 +284,10 @@ void view_for_each_popup(struct sway_view *view,
 void view_init(struct sway_view *view, enum sway_view_type type,
 	const struct sway_view_impl *impl);
 
-void view_free(struct sway_view *view);
-
 void view_destroy(struct sway_view *view);
 
+void view_begin_destroy(struct sway_view *view);
+
 void view_map(struct sway_view *view, struct wlr_surface *wlr_surface);
 
 void view_unmap(struct sway_view *view);

include/sway/tree/workspace.h

@@ -18,6 +18,15 @@ extern char *prev_workspace_name;
 
 struct sway_container *workspace_get_initial_output(const char *name);
 
+struct sway_container *workspace_create(struct sway_container *output,
+		const char *name);
+
+void workspace_destroy(struct sway_container *workspace);
+
+void workspace_begin_destroy(struct sway_container *workspace);
+
+void workspace_consider_destroy(struct sway_container *ws);
+
 char *workspace_next_name(const char *output_name);
 
 bool workspace_switch(struct sway_container *workspace,

sway/commands/move.c

@@ -247,7 +247,7 @@ static void workspace_move_to_output(struct sway_container *workspace,
 	}
 
 	// Try to remove an empty workspace from the destination output.
-	container_reap_empty_recursive(new_output_focus);
+	container_reap_empty(new_output_focus);
 
 	output_sort_workspaces(output);
 	seat_set_focus(seat, output);

sway/config/output.c

@@ -181,13 +181,11 @@ void apply_output_config(struct output_config *oc, struct sway_container *output
 	struct wlr_output *wlr_output = output->sway_output->wlr_output;
 
 	if (oc && oc->enabled == 0) {
-		struct sway_output *sway_output = output->sway_output;
 		if (output->sway_output->bg_pid != 0) {
 			terminate_swaybg(output->sway_output->bg_pid);
 			output->sway_output->bg_pid = 0;
 		}
-		container_destroy(output);
+		output_begin_destroy(output);
-		sway_output->swayc = NULL;
 		wlr_output_layout_remove(root_container.sway_root->output_layout,
 			wlr_output);
 		return;

sway/desktop/output.c

@@ -498,7 +498,7 @@ void output_damage_whole_container(struct sway_output *output,
 static void damage_handle_destroy(struct wl_listener *listener, void *data) {
 	struct sway_output *output =
 		wl_container_of(listener, output, damage_destroy);
-	container_destroy(output->swayc);
+	output_begin_destroy(output->swayc);
 }
 
 static void handle_destroy(struct wl_listener *listener, void *data) {
@@ -506,7 +506,7 @@ static void handle_destroy(struct wl_listener *listener, void *data) {
 	wl_signal_emit(&output->events.destroy, output);
 
 	if (output->swayc) {
-		container_destroy(output->swayc);
+		output_begin_destroy(output->swayc);
 	}
 
 	wl_list_remove(&output->link);

sway/desktop/transaction.c

@@ -54,7 +54,22 @@ static void transaction_destroy(struct sway_transaction *transaction) {
 			con->instruction = NULL;
 		}
 		if (con->destroying && con->ntxnrefs == 0) {
-			container_free(con);
+			switch (con->type) {
+			case C_ROOT:
+				break;
+			case C_OUTPUT:
+				output_destroy(con);
+				break;
+			case C_WORKSPACE:
+				workspace_destroy(con);
+				break;
+			case C_CONTAINER:
+			case C_VIEW:
+				container_destroy(con);
+				break;
+			case C_TYPES:
+				break;
+			}
 		}
 		free(instruction);
 	}

sway/desktop/xdg_shell.c

@@ -448,7 +448,7 @@ static void handle_destroy(struct wl_listener *listener, void *data) {
 	wl_list_remove(&xdg_shell_view->map.link);
 	wl_list_remove(&xdg_shell_view->unmap.link);
 	view->wlr_xdg_surface = NULL;
-	view_destroy(view);
+	view_begin_destroy(view);
 }
 
 struct sway_view *view_from_wlr_xdg_surface(

sway/desktop/xdg_shell_v6.c

@@ -441,7 +441,7 @@ static void handle_destroy(struct wl_listener *listener, void *data) {
 	wl_list_remove(&xdg_shell_v6_view->map.link);
 	wl_list_remove(&xdg_shell_v6_view->unmap.link);
 	view->wlr_xdg_surface_v6 = NULL;
-	view_destroy(view);
+	view_begin_destroy(view);
 }
 
 struct sway_view *view_from_wlr_xdg_surface_v6(

sway/desktop/xwayland.c

@@ -341,7 +341,7 @@ static void handle_destroy(struct wl_listener *listener, void *data) {
 	wl_list_remove(&xwayland_view->set_hints.link);
 	wl_list_remove(&xwayland_view->map.link);
 	wl_list_remove(&xwayland_view->unmap.link);
-	view_destroy(&xwayland_view->view);
+	view_begin_destroy(&xwayland_view->view);
 }
 
 static void handle_unmap(struct wl_listener *listener, void *data) {

sway/input/seat.c

@@ -694,13 +694,11 @@ void seat_set_focus_warp(struct sway_seat *seat,
 
 	// clean up unfocused empty workspace on new output
 	if (new_output_last_ws) {
-		if (!workspace_is_visible(new_output_last_ws)
+		workspace_consider_destroy(new_output_last_ws);
-				&& workspace_is_empty(new_output_last_ws)) {
+		if (new_output_last_ws->destroying &&
-			if (last_workspace == new_output_last_ws) {
+				last_workspace == new_output_last_ws) {
-				last_focus = NULL;
+			last_focus = NULL;
-				last_workspace = NULL;
+			last_workspace = NULL;
-			}
-			container_destroy(new_output_last_ws);
 		}
 	}
 
@@ -716,12 +714,9 @@ void seat_set_focus_warp(struct sway_seat *seat,
 			if (notify && last_workspace != new_workspace) {
 				 ipc_event_workspace(last_workspace, new_workspace, "focus");
 			}
-			if (!workspace_is_visible(last_workspace)
+			workspace_consider_destroy(last_workspace);
-					&& workspace_is_empty(last_workspace)) {
+			if (last_workspace->destroying && last_workspace == last_focus) {
-				if (last_workspace == last_focus) {
+				last_focus = NULL;
-					last_focus = NULL;
-				}
-				container_destroy(last_workspace);
 			}
 		}
 

sway/tree/container.c

@@ -104,209 +104,52 @@ struct sway_container *container_create(enum sway_container_type type) {
 	return c;
 }
 
-static void container_workspace_free(struct sway_workspace *ws) {
+void container_destroy(struct sway_container *con) {
-	list_foreach(ws->output_priority, free);
+	if (!sway_assert(con->type == C_CONTAINER || con->type == C_VIEW,
-	list_free(ws->output_priority);
+				"Expected a container or view")) {
-	list_free(ws->floating);
+		return;
-	free(ws);
+	}
-}
+	if (!sway_assert(con->destroying,
-
-void container_free(struct sway_container *cont) {
-	if (!sway_assert(cont->destroying,
 				"Tried to free container which wasn't marked as destroying")) {
 		return;
 	}
-	if (!sway_assert(cont->ntxnrefs == 0, "Tried to free container "
+	if (!sway_assert(con->ntxnrefs == 0, "Tried to free container "
 				"which is still referenced by transactions")) {
 		return;
 	}
-	free(cont->name);
+	free(con->name);
-	free(cont->formatted_title);
+	free(con->formatted_title);
-	wlr_texture_destroy(cont->title_focused);
+	wlr_texture_destroy(con->title_focused);
-	wlr_texture_destroy(cont->title_focused_inactive);
+	wlr_texture_destroy(con->title_focused_inactive);
-	wlr_texture_destroy(cont->title_unfocused);
+	wlr_texture_destroy(con->title_unfocused);
-	wlr_texture_destroy(cont->title_urgent);
+	wlr_texture_destroy(con->title_urgent);
-	list_free(cont->children);
+	list_free(con->children);
-	list_free(cont->current.children);
+	list_free(con->current.children);
-	list_free(cont->outputs);
+	list_free(con->outputs);
 
-	switch (cont->type) {
+	if (con->type == C_VIEW) {
-	case C_ROOT:
+		struct sway_view *view = con->sway_view;
-		break;
+		view->swayc = NULL;
-	case C_OUTPUT:
+		free(view->title_format);
-		break;
+		view->title_format = NULL;
-	case C_WORKSPACE:
-		container_workspace_free(cont->sway_workspace);
-		break;
-	case C_CONTAINER:
-		break;
-	case C_VIEW:
-		{
-			struct sway_view *view = cont->sway_view;
-			view->swayc = NULL;
-			free(view->title_format);
-			view->title_format = NULL;
 
-			if (view->destroying) {
+		if (view->destroying) {
-				view_free(view);
+			view_destroy(view);
-			}
 		}
-		break;
-	case C_TYPES:
-		sway_assert(false, "Didn't expect to see C_TYPES here");
-		break;
 	}
 
-	free(cont);
+	free(con);
 }
 
-static struct sway_container *container_destroy_noreaping(
+void container_begin_destroy(struct sway_container *con) {
-		struct sway_container *con);
+	if (!sway_assert(con->type == C_CONTAINER || con->type == C_VIEW,
-
+				"Expected a container or view")) {
-static struct sway_container *container_workspace_destroy(
+		return;
-		struct sway_container *workspace) {
-	if (!sway_assert(workspace, "cannot destroy null workspace")) {
-		return NULL;
-	}
-
-	struct sway_container *output = container_parent(workspace, C_OUTPUT);
-
-	// If we're destroying the output, it will be NULL here. Return the root so
-	// that it doesn't appear that the workspace has refused to be destoyed,
-	// which would leave it in a broken state with no parent.
-	if (output == NULL) {
-		return &root_container;
-	}
-
-	// Do not destroy this if it's the last workspace on this output
-	if (output->children->length == 1) {
-		return NULL;
-	}
-
-	wlr_log(WLR_DEBUG, "destroying workspace '%s'", workspace->name);
-
-	if (!workspace_is_empty(workspace)) {
-		// Move children to a different workspace on this output
-		struct sway_container *new_workspace = NULL;
-		for (int i = 0; i < output->children->length; i++) {
-			if (output->children->items[i] != workspace) {
-				new_workspace = output->children->items[i];
-				break;
-			}
-		}
-
-		wlr_log(WLR_DEBUG, "moving children to different workspace '%s' -> '%s'",
-			workspace->name, new_workspace->name);
-		for (int i = 0; i < workspace->children->length; i++) {
-			container_move_to(workspace->children->items[i], new_workspace);
-		}
-		list_t *floating = workspace->sway_workspace->floating;
-		for (int i = 0; i < floating->length; i++) {
-			struct sway_container *floater = floating->items[i];
-			container_remove_child(floater);
-			workspace_add_floating(new_workspace, floater);
-		}
-	}
-
-	return output;
-}
-
-static void untrack_output(struct sway_container *con, void *data) {
-	struct sway_output *output = data;
-	int index = list_find(con->outputs, output);
-	if (index != -1) {
-		list_del(con->outputs, index);
-	}
-}
-
-static struct sway_container *container_output_destroy(
-		struct sway_container *output) {
-	if (!sway_assert(output, "cannot destroy null output")) {
-		return NULL;
-	}
-
-	if (output->children->length > 0) {
-		// TODO save workspaces when there are no outputs.
-		// TODO also check if there will ever be no outputs except for exiting
-		// program
-		if (root_container.children->length > 1) {
-			// Move workspace from this output to another output
-			struct sway_container *fallback_output =
-				root_container.children->items[0];
-			if (fallback_output == output) {
-				fallback_output = root_container.children->items[1];
-			}
-
-			while (output->children->length) {
-				struct sway_container *workspace = output->children->items[0];
-
-				struct sway_container *new_output =
-					workspace_output_get_highest_available(workspace, output);
-				if (!new_output) {
-					new_output = fallback_output;
-					workspace_output_add_priority(workspace, new_output);
-				}
-
-				container_remove_child(workspace);
-				if (!workspace_is_empty(workspace)) {
-					container_add_child(new_output, workspace);
-					ipc_event_workspace(NULL, workspace, "move");
-				} else {
-					container_destroy(workspace);
-				}
-
-				output_sort_workspaces(new_output);
-			}
-		}
-	}
-
-	root_for_each_container(untrack_output, output->sway_output);
-
-	wl_list_remove(&output->sway_output->mode.link);
-	wl_list_remove(&output->sway_output->transform.link);
-	wl_list_remove(&output->sway_output->scale.link);
-
-	wl_list_remove(&output->sway_output->damage_destroy.link);
-	wl_list_remove(&output->sway_output->damage_frame.link);
-
-	output->sway_output->swayc = NULL;
-	output->sway_output = NULL;
-
-	wlr_log(WLR_DEBUG, "OUTPUT: Destroying output '%s'", output->name);
-
-	return &root_container;
-}
-
-/**
- * Implement the actual destroy logic, without reaping.
- */
-static struct sway_container *container_destroy_noreaping(
-		struct sway_container *con) {
-	if (con == NULL) {
-		return NULL;
-	}
-	if (con->destroying) {
-		return NULL;
 	}
 
 	wl_signal_emit(&con->events.destroy, con);
-
-	// emit IPC event
 	if (con->type == C_VIEW) {
 		ipc_event_window(con, "close");
-	} else if (con->type == C_WORKSPACE) {
-		ipc_event_workspace(NULL, con, "empty");
-	}
-
-	// The below functions move their children to somewhere else.
-	if (con->type == C_OUTPUT) {
-		container_output_destroy(con);
-	} else if (con->type == C_WORKSPACE) {
-		// Workspaces will refuse to be destroyed if they're the last workspace
-		// on their output.
-		if (!container_workspace_destroy(con)) {
-			return NULL;
-		}
 	}
 
 	container_end_mouse_operation(con);
@@ -318,51 +161,22 @@ static struct sway_container *container_destroy_noreaping(
 		root_scratchpad_remove_container(con);
 	}
 
-	if (!con->parent) {
+	if (con->parent) {
-		return NULL;
+		container_remove_child(con);
 	}
-
-	return container_remove_child(con);
 }
 
-bool container_reap_empty(struct sway_container *con) {
+struct sway_container *container_reap_empty(struct sway_container *con) {
-	switch (con->type) {
+	while (con && con->type == C_CONTAINER) {
-	case C_ROOT:
-	case C_OUTPUT:
-		// dont reap these
-		break;
-	case C_WORKSPACE:
-		if (!workspace_is_visible(con) && workspace_is_empty(con)) {
-			wlr_log(WLR_DEBUG, "Destroying workspace via reaper");
-			container_destroy_noreaping(con);
-			return true;
-		}
-		break;
-	case C_CONTAINER:
-		if (con->children->length == 0) {
-			container_destroy_noreaping(con);
-			return true;
-		}
-	case C_VIEW:
-		break;
-	case C_TYPES:
-		sway_assert(false, "container_reap_empty called on an invalid "
-			"container");
-		break;
-	}
-
-	return false;
-}
-
-struct sway_container *container_reap_empty_recursive(
-		struct sway_container *con) {
-	while (con) {
 		struct sway_container *next = con->parent;
-		if (!container_reap_empty(con)) {
+		if (con->children->length == 0) {
-			break;
+			container_begin_destroy(con);
 		}
 		con = next;
 	}
+	if (con && con->type == C_WORKSPACE) {
+		workspace_consider_destroy(con);
+	}
 	return con;
 }
 
@@ -371,34 +185,12 @@ struct sway_container *container_flatten(struct sway_container *container) {
 		struct sway_container *child = container->children->items[0];
 		struct sway_container *parent = container->parent;
 		container_replace_child(container, child);
-		container_destroy_noreaping(container);
+		container_begin_destroy(container);
 		container = parent;
 	}
 	return container;
 }
 
-/**
- * container_destroy() is the first step in destroying a container. We'll emit
- * events, detach it from the tree and mark it as destroying. The container will
- * remain in memory until it's no longer used by a transaction, then it will be
- * freed via container_free().
- *
- * This function just wraps container_destroy_noreaping(), then does reaping.
- */
-struct sway_container *container_destroy(struct sway_container *con) {
-	if (con->is_fullscreen) {
-		struct sway_container *ws = container_parent(con, C_WORKSPACE);
-		ws->sway_workspace->fullscreen = NULL;
-	}
-	struct sway_container *parent = container_destroy_noreaping(con);
-
-	if (!parent) {
-		return NULL;
-	}
-
-	return container_reap_empty_recursive(parent);
-}
-
 static void container_close_func(struct sway_container *container, void *data) {
 	if (container->type == C_VIEW) {
 		view_close(container->sway_view);

sway/tree/layout.c

@@ -302,7 +302,7 @@ static void workspace_rejigger(struct sway_container *ws,
 		move_dir == MOVE_LEFT || move_dir == MOVE_RIGHT ? L_HORIZ : L_VERT;
 
 	container_flatten(ws);
-	container_reap_empty_recursive(original_parent);
+	container_reap_empty(original_parent);
 	container_create_notify(new_parent);
 }
 
@@ -325,7 +325,7 @@ static void move_out_of_tabs_stacks(struct sway_container *container,
 		container_insert_child(new_parent->parent, container, offs < 0 ? 0 : 1);
 	} else {
 		container_insert_child(new_parent, container, offs < 0 ? 0 : 1);
-		container_reap_empty_recursive(new_parent->parent);
+		container_reap_empty(new_parent->parent);
 		container_flatten(new_parent->parent);
 	}
 	container_create_notify(new_parent);

sway/tree/output.c

@@ -10,6 +10,7 @@
 #include "log.h"
 
 static void restore_workspaces(struct sway_container *output) {
+	// Workspace output priority
 	for (int i = 0; i < root_container.children->length; i++) {
 		struct sway_container *other = root_container.children->items[i];
 		if (other == output) {
@@ -29,6 +30,15 @@ static void restore_workspaces(struct sway_container *output) {
 		}
 	}
 
+	// Saved workspaces
+	list_t *saved = root_container.sway_root->saved_workspaces;
+	for (int i = 0; i < saved->length; ++i) {
+		struct sway_container *ws = saved->items[i];
+		container_add_child(output, ws);
+		ipc_event_workspace(NULL, ws, "move");
+	}
+	saved->length = 0;
+
 	output_sort_workspaces(output);
 }
 
@@ -68,7 +78,7 @@ struct sway_container *output_create(
 	output->sway_output = sway_output;
 	output->name = strdup(name);
 	if (output->name == NULL) {
-		container_destroy(output);
+		output_begin_destroy(output);
 		return NULL;
 	}
 
@@ -103,6 +113,102 @@ struct sway_container *output_create(
 	return output;
 }
 
+static void output_evacuate(struct sway_container *output) {
+	if (!output->children->length) {
+		return;
+	}
+	struct sway_container *fallback_output = NULL;
+	if (root_container.children->length > 1) {
+		fallback_output = root_container.children->items[0];
+		if (fallback_output == output) {
+			fallback_output = root_container.children->items[1];
+		}
+	}
+
+	while (output->children->length) {
+		struct sway_container *workspace = output->children->items[0];
+
+		struct sway_container *new_output =
+			workspace_output_get_highest_available(workspace, output);
+		if (!new_output) {
+			new_output = fallback_output;
+		}
+
+		container_remove_child(workspace);
+
+		if (new_output) {
+			workspace_output_add_priority(workspace, new_output);
+			container_add_child(new_output, workspace);
+			output_sort_workspaces(new_output);
+			ipc_event_workspace(NULL, workspace, "move");
+		} else {
+			list_add(root_container.sway_root->saved_workspaces, workspace);
+		}
+	}
+}
+
+void output_destroy(struct sway_container *output) {
+	if (!sway_assert(output->type == C_OUTPUT, "Expected an output")) {
+		return;
+	}
+	if (!sway_assert(output->destroying,
+				"Tried to free output which wasn't marked as destroying")) {
+		return;
+	}
+	if (!sway_assert(output->ntxnrefs == 0, "Tried to free output "
+				"which is still referenced by transactions")) {
+		return;
+	}
+	free(output->name);
+	free(output->formatted_title);
+	wlr_texture_destroy(output->title_focused);
+	wlr_texture_destroy(output->title_focused_inactive);
+	wlr_texture_destroy(output->title_unfocused);
+	wlr_texture_destroy(output->title_urgent);
+	list_free(output->children);
+	list_free(output->current.children);
+	list_free(output->outputs);
+	free(output);
+
+	// NOTE: We don't actually destroy the sway_output here
+}
+
+static void untrack_output(struct sway_container *con, void *data) {
+	struct sway_output *output = data;
+	int index = list_find(con->outputs, output);
+	if (index != -1) {
+		list_del(con->outputs, index);
+	}
+}
+
+void output_begin_destroy(struct sway_container *output) {
+	if (!sway_assert(output->type == C_OUTPUT, "Expected an output")) {
+		return;
+	}
+	wlr_log(WLR_DEBUG, "OUTPUT: Destroying output '%s'", output->name);
+	wl_signal_emit(&output->events.destroy, output);
+
+	output_evacuate(output);
+
+	output->destroying = true;
+	container_set_dirty(output);
+
+	root_for_each_container(untrack_output, output->sway_output);
+
+	wl_list_remove(&output->sway_output->mode.link);
+	wl_list_remove(&output->sway_output->transform.link);
+	wl_list_remove(&output->sway_output->scale.link);
+	wl_list_remove(&output->sway_output->damage_destroy.link);
+	wl_list_remove(&output->sway_output->damage_frame.link);
+
+	output->sway_output->swayc = NULL;
+	output->sway_output = NULL;
+
+	if (output->parent) {
+		container_remove_child(output);
+	}
+}
+
 void output_for_each_workspace(struct sway_container *output,
 		void (*f)(struct sway_container *con, void *data), void *data) {
 	if (!sway_assert(output->type == C_OUTPUT, "Expected an output")) {

sway/tree/root.c

@@ -39,6 +39,7 @@ void root_create(void) {
 	wl_list_init(&root_container.sway_root->drag_icons);
 	wl_signal_init(&root_container.sway_root->events.new_container);
 	root_container.sway_root->scratchpad = create_list();
+	root_container.sway_root->saved_workspaces = create_list();
 
 	root_container.sway_root->output_layout_change.notify =
 		output_layout_handle_change;
@@ -50,6 +51,7 @@ void root_destroy(void) {
 	// sway_root
 	wl_list_remove(&root_container.sway_root->output_layout_change.link);
 	list_free(root_container.sway_root->scratchpad);
+	list_free(root_container.sway_root->saved_workspaces);
 	wlr_output_layout_destroy(root_container.sway_root->output_layout);
 	free(root_container.sway_root);
 

sway/tree/view.c

@@ -35,7 +35,7 @@ void view_init(struct sway_view *view, enum sway_view_type type,
 	wl_signal_init(&view->events.unmap);
 }
 
-void view_free(struct sway_view *view) {
+void view_destroy(struct sway_view *view) {
 	if (!sway_assert(view->surface == NULL, "Tried to free mapped view")) {
 		return;
 	}
@@ -75,14 +75,14 @@ void view_free(struct sway_view *view) {
  * destroying flag will make the view get freed when the transaction is
  * finished.
  */
-void view_destroy(struct sway_view *view) {
+void view_begin_destroy(struct sway_view *view) {
 	if (!sway_assert(view->surface == NULL, "Tried to destroy a mapped view")) {
 		return;
 	}
 	view->destroying = true;
 
 	if (!view->swayc) {
-		view_free(view);
+		view_destroy(view);
 	}
 }
 
@@ -560,7 +560,9 @@ void view_unmap(struct sway_view *view) {
 	}
 
 	bool was_fullscreen = view->swayc->is_fullscreen;
-	struct sway_container *surviving_ancestor = container_destroy(view->swayc);
+	struct sway_container *parent = view->swayc->parent;
+	container_begin_destroy(view->swayc);
+	struct sway_container *surviving_ancestor = container_reap_empty(parent);
 
 	// If the workspace wasn't reaped
 	if (surviving_ancestor && surviving_ancestor->type >= C_WORKSPACE) {

sway/tree/workspace.c

@@ -79,6 +79,65 @@ struct sway_container *workspace_create(struct sway_container *output,
 	return workspace;
 }
 
+void workspace_destroy(struct sway_container *workspace) {
+	if (!sway_assert(workspace->type == C_WORKSPACE, "Expected a workspace")) {
+		return;
+	}
+	if (!sway_assert(workspace->destroying,
+				"Tried to free workspace which wasn't marked as destroying")) {
+		return;
+	}
+	if (!sway_assert(workspace->ntxnrefs == 0, "Tried to free workspace "
+				"which is still referenced by transactions")) {
+		return;
+	}
+	// sway_workspace
+	struct sway_workspace *ws = workspace->sway_workspace;
+	list_foreach(ws->output_priority, free);
+	list_free(ws->output_priority);
+	list_free(ws->floating);
+	free(ws);
+
+	// swayc
+	free(workspace->name);
+	free(workspace->formatted_title);
+	wlr_texture_destroy(workspace->title_focused);
+	wlr_texture_destroy(workspace->title_focused_inactive);
+	wlr_texture_destroy(workspace->title_unfocused);
+	wlr_texture_destroy(workspace->title_urgent);
+	list_free(workspace->children);
+	list_free(workspace->current.children);
+	list_free(workspace->outputs);
+	free(workspace);
+}
+
+void workspace_begin_destroy(struct sway_container *workspace) {
+	if (!sway_assert(workspace->type == C_WORKSPACE, "Expected a workspace")) {
+		return;
+	}
+	wlr_log(WLR_DEBUG, "Destroying workspace '%s'", workspace->name);
+	wl_signal_emit(&workspace->events.destroy, workspace);
+	ipc_event_workspace(NULL, workspace, "empty"); // intentional
+
+	workspace->destroying = true;
+	container_set_dirty(workspace);
+
+	if (workspace->parent) {
+		container_remove_child(workspace);
+	}
+}
+
+void workspace_consider_destroy(struct sway_container *ws) {
+	if (!sway_assert(ws->type == C_WORKSPACE, "Expected a workspace")) {
+		return;
+	}
+	struct sway_seat *seat = input_manager_current_seat(input_manager);
+	if (ws->children->length == 0 && ws->sway_workspace->floating->length == 0
+			&& seat_get_active_child(seat, ws->parent) != ws) {
+		workspace_begin_destroy(ws);
+	}
+}
+
 char *prev_workspace_name = NULL;
 
 void next_name_map(struct sway_container *ws, void *data) {
@@ -421,9 +480,7 @@ bool workspace_switch(struct sway_container *workspace,
 		// no op. We therefore need to send the IPC event and clean up the old
 		// workspace here.
 		ipc_event_workspace(active_ws, workspace, "focus");
-		if (!workspace_is_visible(active_ws) && workspace_is_empty(active_ws)) {
+		workspace_consider_destroy(active_ws);
-			container_destroy(active_ws);
-		}
 	}
 	seat_set_focus(seat, next);
 	struct sway_container *output = container_parent(workspace, C_OUTPUT);