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.

5 files changed, 21 insertions, 6 deletions

diff --git a/sway/desktop/output.c b/sway/desktop/output.c
index 3d8bbff5..401d3c44 100644
--- a/sway/desktop/output.c
+++ b/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);
diff --git a/sway/desktop/transaction.c b/sway/desktop/transaction.c
index f82e5ef2..c18529fb 100644
--- a/sway/desktop/transaction.c
+++ b/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);
 	}
diff --git a/sway/desktop/xdg_shell.c b/sway/desktop/xdg_shell.c
index aae129bd..f5aaa575 100644
--- a/sway/desktop/xdg_shell.c
+++ b/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(
diff --git a/sway/desktop/xdg_shell_v6.c b/sway/desktop/xdg_shell_v6.c
index 277c53a3..f623b77b 100644
--- a/sway/desktop/xdg_shell_v6.c
+++ b/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(
diff --git a/sway/desktop/xwayland.c b/sway/desktop/xwayland.c
index ce7235e4..6fcc850d 100644
--- a/sway/desktop/xwayland.c
+++ b/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) {