Deny moving a sticky container to workspace if it's the same output

Rationale: Sticky containers are always assigned to the visible
workspace.

The basic idea here is to check the destination's output (move.c:190).
But if the command was `move container to workspace x` then a workspace
might have been created for it. We could destroy the workspace in this
case, but that results in unnecessary IPC events.

To avoid this, the logic for `move container to workspace x` has been
adjusted. It now delays creating the workspace until the end, and uses
`workspace_get_initial_output` to determine and check the output before
creating it.

2 files changed, 33 insertions, 9 deletions

diff --git a/sway/commands/move.c b/sway/commands/move.c
index 95dcb088..de6b1b0a 100644
--- a/sway/commands/move.c
+++ b/sway/commands/move.c
@@ -100,7 +100,8 @@ static struct cmd_results *cmd_move_container(struct sway_container *current,
         // determine destination
         if (strcasecmp(argv[1], "workspace") == 0) {
                 // move container to workspace x
-                struct sway_container *ws;
+                struct sway_container *ws = NULL;
+                char *ws_name = NULL;
                 if (strcasecmp(argv[2], "next") == 0 ||
                                 strcasecmp(argv[2], "prev") == 0 ||
                                 strcasecmp(argv[2], "next_on_output") == 0 ||
@@ -110,14 +111,13 @@ static struct cmd_results *cmd_move_container(struct sway_container *current,
                 } else if (strcasecmp(argv[2], "back_and_forth") == 0) {
                         if (!(ws = workspace_by_name(argv[2]))) {
                                 if (prev_workspace_name) {
-                                        ws = workspace_create(NULL, prev_workspace_name);
+                                        ws_name = strdup(prev_workspace_name);
                                 } else {
                                         return cmd_results_new(CMD_FAILURE, "move",
                                                         "No workspace was previously active.");
                                 }
                         }
                 } else {
-                        char *ws_name = NULL;
                         if (strcasecmp(argv[2], "number") == 0) {
                                 // move "container to workspace number x"
                                 if (argc < 4) {
@@ -141,12 +141,26 @@ static struct cmd_results *cmd_move_container(struct sway_container *current,
                                         ws = workspace_by_name(ws_name);
                                 }
                         }
-
-                        if (!ws) {
-                                ws = workspace_create(NULL, ws_name);
+                }
+                if (!ws) {
+                        // We have to create the workspace, but if the container is
+                        // sticky and the workspace is going to be created on the same
+                        // output, we'll bail out first.
+                        if (container_is_floating(current) && current->is_sticky) {
+                                struct sway_container *old_output =
+                                        container_parent(current, C_OUTPUT);
+                                struct sway_container *new_output =
+                                        workspace_get_initial_output(ws_name);
+                                if (old_output == new_output) {
+                                        free(ws_name);
+                                        return cmd_results_new(CMD_FAILURE, "move",
+                                                        "Can't move sticky container to another workspace "
+                                                        "on the same output");
+                                }
                         }
-                        free(ws_name);
+                        ws = workspace_create(NULL, ws_name);
                 }
+                free(ws_name);
                 destination = seat_get_focus_inactive(config->handler_context.seat, ws);
         } else if (strcasecmp(argv[1], "output") == 0) {
                 struct sway_container *source = container_parent(current, C_OUTPUT);
@@ -173,6 +187,16 @@ static struct cmd_results *cmd_move_container(struct sway_container *current,
                 return cmd_results_new(CMD_INVALID, "move", expected_syntax);
         }
 
+        if (container_is_floating(current) && current->is_sticky) {
+                struct sway_container *old_output = container_parent(current, C_OUTPUT);
+                struct sway_container *new_output = destination->type == C_OUTPUT ?
+                        destination : container_parent(destination, C_OUTPUT);
+                if (old_output == new_output) {
+                        return cmd_results_new(CMD_FAILURE, "move", "Can't move sticky "
+                                        "container to another workspace on the same output");
+                }
+        }
+
         // move container, arrange windows and return focus
         container_move_to(current, destination);
         struct sway_container *focus =
diff --git a/sway/tree/workspace.c b/sway/tree/workspace.c
index 395c6c10..b8bec044 100644
--- a/sway/tree/workspace.c
+++ b/sway/tree/workspace.c
@@ -18,7 +18,7 @@
 #include "log.h"
 #include "util.h"
 
-static struct sway_container *get_workspace_initial_output(const char *name) {
+struct sway_container *workspace_get_initial_output(const char *name) {
         struct sway_container *parent;
         // Search for workspace<->output pair
         int e = config->workspace_outputs->length;
@@ -48,7 +48,7 @@ static struct sway_container *get_workspace_initial_output(const char *name) {
 struct sway_container *workspace_create(struct sway_container *output,
                 const char *name) {
         if (output == NULL) {
-                output = get_workspace_initial_output(name);
+                output = workspace_get_initial_output(name);
         }
 
         wlr_log(WLR_DEBUG, "Added workspace %s for output %s", name, output->name);