ext-workspace-v1: initial implementation

Maintain a 1:1 relationship between workspace groups and outputs, so
that moving a workspace across groups effectively moves it across
outputs.

ext_workspace_handle_v1::id is never emitted; sway has no concept of ids
or of stable vs temporary workspaces. Everything is ephemeral to the
current session.

ext_workspace_handle_v1::coordinates is never emitted; sway does not
organise workspaces into any sort of grid.

ext_workspace_handle_v1::assign is mostly untested, because no client
current implements this. Perhaps it's best to not-advertise the feature
for now?

Deactivating a workspace is a no-op. This functionality doesn't really
align with sway, although it could potentially be implemented to "switch
to previous workspace on this output" as a follow-up.

Removing a workspace is a no-op.

Implements: https://github.com/swaywm/sway/issues/8812

include/sway/output.h

@@ -63,6 +63,7 @@ struct sway_output {
 	struct wl_listener request_state;
 
 	struct wlr_color_transform *color_transform;
+	struct wlr_ext_workspace_group_handle_v1 *ext_workspace_group;
 
 	struct timespec last_presentation;
 	uint32_t refresh_nsec;

include/sway/server.h

@@ -127,6 +127,9 @@ struct sway_server {
 	struct wl_listener tearing_control_new_object;
 	struct wl_list tearing_controllers; // sway_tearing_controller::link
 
+	struct wlr_ext_workspace_manager_v1 *workspace_manager_v1;
+	struct wl_listener workspace_manager_v1_commit;
+
 	struct wl_list pending_launcher_ctxs; // launcher_ctx::link
 
 	// The timeout for transactions, after which a transaction is applied

include/sway/tree/workspace.h

@@ -3,6 +3,7 @@
 
 #include <stdbool.h>
 #include <wlr/types/wlr_scene.h>
+#include <wlr/types/wlr_ext_workspace_v1.h>
 #include "sway/config.h"
 #include "sway/tree/container.h"
 #include "sway/tree/node.h"
@@ -51,6 +52,7 @@ struct sway_workspace {
 	bool urgent;
 
 	struct sway_workspace_state current;
+	struct wlr_ext_workspace_handle_v1 *ext_workspace; // Always set.
 };
 
 struct workspace_config *workspace_find_config(const char *ws_name);
@@ -160,4 +162,8 @@ void workspace_squash(struct sway_workspace *workspace);
 void workspace_move_to_output(struct sway_workspace *workspace,
 		struct sway_output *output);
 
+void sway_ext_workspace_init(void);
+void sway_ext_workspace_output_enable(struct sway_output *output);
+void sway_ext_workspace_output_disable(struct sway_output *output);
+
 #endif

sway/commands/rename.c

@@ -1,6 +1,7 @@
 #include <ctype.h>
 #include <string.h>
 #include <strings.h>
+#include <wlr/types/wlr_ext_workspace_v1.h>
 #include "log.h"
 #include "stringop.h"
 #include "sway/commands.h"
@@ -95,6 +96,8 @@ struct cmd_results *cmd_rename(int argc, char **argv) {
 	free(workspace->name);
 	workspace->name = new_name;
 
+	wlr_ext_workspace_handle_v1_set_name(workspace->ext_workspace, workspace->name);
+
 	output_sort_workspaces(workspace->output);
 	ipc_event_workspace(NULL, workspace, "rename");
 

sway/input/seat.c

@@ -6,6 +6,7 @@
 #include <wlr/config.h>
 #include <wlr/types/wlr_cursor.h>
 #include <wlr/types/wlr_data_device.h>
+#include <wlr/types/wlr_ext_workspace_v1.h>
 #include <wlr/types/wlr_idle_notify_v1.h>
 #include <wlr/types/wlr_keyboard_group.h>
 #include <wlr/types/wlr_output_layout.h>
@@ -1204,6 +1205,15 @@ static void seat_set_workspace_focus(struct sway_seat *seat, struct sway_node *n
 		ipc_event_window(container, "focus");
 	}
 
+	if (last_workspace && last_workspace != new_workspace) {
+		wlr_ext_workspace_handle_v1_set_active(last_workspace->ext_workspace,
+			workspace_is_visible(last_workspace));
+	}
+	if (new_workspace) {
+		wlr_ext_workspace_handle_v1_set_active(new_workspace->ext_workspace,
+			workspace_is_visible(new_workspace));
+	}
+
 	// Move sticky containers to new workspace
 	if (new_workspace && new_output_last_ws
 			&& new_workspace != new_output_last_ws) {

sway/server.c

@@ -63,6 +63,7 @@
 #include "sway/server.h"
 #include "sway/input/cursor.h"
 #include "sway/tree/root.h"
+#include "sway/tree/workspace.h"
 
 #if WLR_HAS_XWAYLAND
 #include <wlr/xwayland/shell.h>
@@ -377,6 +378,7 @@ bool server_init(struct sway_server *server) {
 		wlr_foreign_toplevel_manager_v1_create(server->wl_display);
 
 	sway_session_lock_init();
+	sway_ext_workspace_init();
 
 #if WLR_HAS_DRM_BACKEND
 	server->drm_lease_manager=
@@ -543,6 +545,7 @@ void server_fini(struct sway_server *server) {
 	wl_list_remove(&server->xdg_toplevel_tag_manager_v1_set_tag.link);
 	wl_list_remove(&server->request_set_cursor_shape.link);
 	wl_list_remove(&server->new_foreign_toplevel_capture_request.link);
+	wl_list_remove(&server->workspace_manager_v1_commit.link);
 	input_manager_finish(server->input);
 
 	// TODO: free sway-specific resources

sway/tree/output.c

@@ -2,6 +2,8 @@
 #include <ctype.h>
 #include <string.h>
 #include <strings.h>
+#include <wlr/types/wlr_ext_workspace_v1.h>
+#include "sway/tree/workspace.h"
 #include "sway/ipc-server.h"
 #include "sway/layers.h"
 #include "sway/output.h"
@@ -153,6 +155,7 @@ void output_enable(struct sway_output *output) {
 	output->enabled = true;
 	list_add(root->outputs, output);
 
+	sway_ext_workspace_output_enable(output);
 	restore_workspaces(output);
 
 	struct sway_workspace *ws = NULL;
@@ -292,6 +295,7 @@ void output_disable(struct sway_output *output) {
 
 	destroy_layers(output);
 	output_evacuate(output);
+	sway_ext_workspace_output_disable(output);
 }
 
 void output_begin_destroy(struct sway_output *output) {
@@ -333,6 +337,10 @@ void output_add_workspace(struct sway_output *output,
 	}
 	list_add(output->workspaces, workspace);
 	workspace->output = output;
+	if (workspace->output && workspace->output->ext_workspace_group) {
+		wlr_ext_workspace_handle_v1_set_group(workspace->ext_workspace,
+			workspace->output->ext_workspace_group);
+	}
 	node_set_dirty(&output->node);
 	node_set_dirty(&workspace->node);
 }

sway/tree/workspace.c

@@ -3,8 +3,12 @@
 #include <stdbool.h>
 #include <stdlib.h>
 #include <stdio.h>
+#include <string.h>
 #include <strings.h>
+#include <wlr/types/wlr_ext_workspace_v1.h>
+#include "log.h"
 #include "stringop.h"
+#include "sway/desktop/transaction.h"
 #include "sway/input/input-manager.h"
 #include "sway/input/cursor.h"
 #include "sway/input/seat.h"
@@ -17,9 +21,124 @@
 #include "sway/tree/view.h"
 #include "sway/tree/workspace.h"
 #include "list.h"
-#include "log.h"
 #include "util.h"
 
+static const uint32_t WORKSPACE_CAPABILITIES =
+	EXT_WORKSPACE_HANDLE_V1_WORKSPACE_CAPABILITIES_ACTIVATE |
+	EXT_WORKSPACE_HANDLE_V1_WORKSPACE_CAPABILITIES_ASSIGN;
+
+static const uint32_t GROUP_CAPABILITIES =
+	EXT_WORKSPACE_GROUP_HANDLE_V1_GROUP_CAPABILITIES_CREATE_WORKSPACE;
+
+// Helper to find the output associated with a workspace group.
+static struct sway_output *group_to_output(
+		struct wlr_ext_workspace_group_handle_v1 *group) {
+	for (int i = 0; i < root->outputs->length; i++) {
+		struct sway_output *output = root->outputs->items[i];
+		if (output->ext_workspace_group == group) {
+			return output;
+		}
+	}
+	abort(); // unreachable
+}
+
+// Callback for ext-workspace-v1 commit events.
+static void handle_commit(struct wl_listener *listener, void *data) {
+	struct sway_server *server =
+		wl_container_of(listener, server, workspace_manager_v1_commit);
+	struct wlr_ext_workspace_v1_commit_event *event = data;
+
+	struct wlr_ext_workspace_v1_request *req, *tmp;
+	wl_list_for_each_safe(req, tmp, event->requests, link) {
+		switch (req->type) {
+		case WLR_EXT_WORKSPACE_V1_REQUEST_ACTIVATE:
+			if (req->activate.workspace) {
+				workspace_switch(req->activate.workspace->data);
+			}
+			break;
+		case WLR_EXT_WORKSPACE_V1_REQUEST_CREATE_WORKSPACE:;
+			struct sway_output *output = group_to_output(req->create_workspace.group);
+			sway_assert(output, "NULL output given to create_workspace");
+
+			char *name;
+			if (req->create_workspace.name) {
+				if (workspace_by_name(req->create_workspace.name)) {
+					sway_log(SWAY_ERROR, "Refusing to create workspace with duplicate name.");
+					break; // Already exists.
+				}
+				name = strdup(req->create_workspace.name);
+			} else {
+				name = workspace_next_name(output->wlr_output->name);
+			}
+
+			struct sway_workspace *new_ws = workspace_create(output, name);
+			if (new_ws) {
+				workspace_switch(new_ws);
+			}
+			free(name);
+			break;
+		case WLR_EXT_WORKSPACE_V1_REQUEST_ASSIGN:;
+			if (!req->assign.workspace || !req->assign.group) break;
+
+			struct sway_workspace *ws = req->assign.workspace->data;
+			struct sway_output *new_output = group_to_output(req->assign.group);
+			struct sway_output *old_output = ws->output;
+			workspace_move_to_output(ws, new_output);
+			arrange_output(old_output);
+			arrange_output(new_output);
+			break;
+		case WLR_EXT_WORKSPACE_V1_REQUEST_DEACTIVATE:
+		case WLR_EXT_WORKSPACE_V1_REQUEST_REMOVE:
+			break; // No-op.
+		}
+	}
+
+	transaction_commit_dirty();
+}
+
+// Initialize ext-workspace. Must be called once at startup.
+void sway_ext_workspace_init(void) {
+	server.workspace_manager_v1 =
+		wlr_ext_workspace_manager_v1_create(server.wl_display, 1);
+	if (!server.workspace_manager_v1) {
+		sway_log(SWAY_ERROR, "Failed to create ext_workspace_manager_v1");
+		return;
+	}
+
+	server.workspace_manager_v1_commit.notify = handle_commit;
+	wl_signal_add(&server.workspace_manager_v1->events.commit,
+		&server.workspace_manager_v1_commit);
+}
+
+// Must be called whenever an output is enabled.
+void sway_ext_workspace_output_enable(struct sway_output *output) {
+	if (!output->wlr_output) {
+		return;
+	}
+
+	output->ext_workspace_group =
+		wlr_ext_workspace_group_handle_v1_create(
+			server.workspace_manager_v1, GROUP_CAPABILITIES);
+	if (!output->ext_workspace_group) {
+		sway_log(SWAY_ERROR, "Failed to create workspace group for output '%s'",
+			output->wlr_output->name);
+		return;
+	}
+
+	wlr_ext_workspace_group_handle_v1_output_enter(
+		output->ext_workspace_group, output->wlr_output);
+}
+
+// Must be called whenever an output is disabled.
+void sway_ext_workspace_output_disable(struct sway_output *output) {
+	if (!output->ext_workspace_group) {
+		return;
+	}
+
+	wlr_ext_workspace_group_handle_v1_destroy(output->ext_workspace_group);
+	output->ext_workspace_group = NULL;
+}
+
 struct workspace_config *workspace_find_config(const char *ws_name) {
 	for (int i = 0; i < config->workspace_configs->length; ++i) {
 		struct workspace_config *wsc = config->workspace_configs->items[i];
@@ -70,6 +189,16 @@ struct sway_workspace *workspace_create(struct sway_output *output,
 		sway_log(SWAY_ERROR, "Unable to allocate sway_workspace");
 		return NULL;
 	}
+
+	ws->ext_workspace = wlr_ext_workspace_handle_v1_create(
+		server.workspace_manager_v1, NULL, WORKSPACE_CAPABILITIES);
+	if (!ws->ext_workspace) {
+		sway_log(SWAY_ERROR, "Failed to create ext_workspace for '%s'", name);
+		free(ws);
+		return NULL;
+	}
+	ws->ext_workspace->data = ws;
+
 	node_init(&ws->node, N_WORKSPACE, ws);
 
 	bool failed = false;
@@ -79,6 +208,7 @@ struct sway_workspace *workspace_create(struct sway_output *output,
 	if (failed) {
 		wlr_scene_node_destroy(&ws->layers.tiling->node);
 		wlr_scene_node_destroy(&ws->layers.fullscreen->node);
+		wlr_ext_workspace_handle_v1_destroy(ws->ext_workspace);
 		free(ws);
 		return NULL;
 	}
@@ -127,6 +257,13 @@ struct sway_workspace *workspace_create(struct sway_output *output,
 	output_add_workspace(output, ws);
 	output_sort_workspaces(output);
 
+	wlr_ext_workspace_handle_v1_set_name(ws->ext_workspace, ws->name);
+	if (ws->output && ws->output->ext_workspace_group) {
+		wlr_ext_workspace_handle_v1_set_group(ws->ext_workspace,
+			ws->output->ext_workspace_group);
+	}
+	wlr_ext_workspace_handle_v1_set_active(ws->ext_workspace,
+		workspace_is_visible(ws));
 	ipc_event_workspace(NULL, ws, "init");
 	wl_signal_emit_mutable(&root->events.new_node, &ws->node);
 
@@ -163,6 +300,9 @@ void workspace_begin_destroy(struct sway_workspace *workspace) {
 	ipc_event_workspace(NULL, workspace, "empty"); // intentional
 	wl_signal_emit_mutable(&workspace->node.events.destroy, &workspace->node);
 
+	wlr_ext_workspace_handle_v1_destroy(workspace->ext_workspace);
+	workspace->ext_workspace = NULL;
+
 	if (workspace->output) {
 		workspace_detach(workspace);
 	}
@@ -687,6 +827,7 @@ void workspace_detect_urgent(struct sway_workspace *workspace) {
 
 	if (workspace->urgent != new_urgent) {
 		workspace->urgent = new_urgent;
+		wlr_ext_workspace_handle_v1_set_urgent(workspace->ext_workspace, workspace->urgent);
 		ipc_event_workspace(NULL, workspace, "urgent");
 	}
 }