swaybar: handle mode/hidden_state changes

As well as adding the hidden_state property to the bar config struct,
this commit handles barconfig_update events when the mode or
hidden_state changes, and uses a new function determine_bar_visibility
to hide or show the bar as required, using, respectively,
destroy_layer_surface, which is also newly added, and add_layer_surface,
which has been changed to allow dynamically adding the surface.

include/swaybar/bar.h

@@ -50,6 +50,11 @@ struct swaybar {
 	char *mode;
 	bool mode_pango_markup;
 
+	// only relevant when bar is in "hide" mode
+	bool visible_by_modifier;
+	bool visible_by_urgency;
+	bool visible;
+
 	struct wl_display *display;
 	struct wl_compositor *compositor;
 	struct zwlr_layer_shell_v1 *layer_shell;
@@ -104,6 +109,19 @@ bool bar_setup(struct swaybar *bar, const char *socket_path);
 void bar_run(struct swaybar *bar);
 void bar_teardown(struct swaybar *bar);
 
+/*
+ * Determines whether the bar should be visible and changes it to be so.
+ * If the current visibility of the bar is the different to what it should be,
+ * then it adds or destroys the layer surface as required,
+ * as well as sending the cont or stop signal to the status command.
+ * If the current visibility of the bar is already what it should be,
+ * then this function is a no-op, unless moving_layer is true, which occurs
+ * when the bar changes from "hide" to "dock" mode or vice versa, and the bar
+ * needs to be destroyed and re-added in order to change its layer.
+ *
+ * Returns true if the bar is now visible, otherwise false.
+ */
+bool determine_bar_visibility(struct swaybar *bar, bool moving_layer);
 void free_hotspots(struct wl_list *list);
 void free_workspaces(struct wl_list *list);
 

include/swaybar/config.h

@@ -31,6 +31,7 @@ struct swaybar_config {
 	char *font;
 	char *sep_symbol;
 	char *mode;
+	char *hidden_state;
 	bool strip_workspace_numbers;
 	bool binding_mode_indicator;
 	bool wrap_scroll;

swaybar/bar.c

@@ -32,6 +32,7 @@
 
 static void bar_init(struct swaybar *bar) {
 	bar->config = init_config();
+	bar->visible = true;
 	wl_list_init(&bar->outputs);
 }
 
@@ -338,21 +339,65 @@ const struct wl_seat_listener seat_listener = {
 };
 
 static void add_layer_surface(struct swaybar_output *output) {
-	if (output->surface != NULL) {
+	if (output->layer_surface) {
 		return;
 	}
 	struct swaybar *bar = output->bar;
 
-	output->surface = wl_compositor_create_surface(bar->compositor);
+	struct swaybar_config *config = bar->config;
-	assert(output->surface);
+	bool hidden = strcmp(config->mode, "hide") == 0;
 	output->layer_surface = zwlr_layer_shell_v1_get_layer_surface(
 			bar->layer_shell, output->surface, output->output,
+			hidden ? ZWLR_LAYER_SHELL_V1_LAYER_TOP :
 			ZWLR_LAYER_SHELL_V1_LAYER_BOTTOM, "panel");
 	assert(output->layer_surface);
 	zwlr_layer_surface_v1_add_listener(output->layer_surface,
 			&layer_surface_listener, output);
-	zwlr_layer_surface_v1_set_anchor(output->layer_surface,
+
-			bar->config->position);
+	zwlr_layer_surface_v1_set_anchor(output->layer_surface, config->position);
+	if (hidden) {
+		zwlr_layer_surface_v1_set_exclusive_zone(output->layer_surface, -1);
+	}
+}
+
+static void destroy_layer_surface(struct swaybar_output *output) {
+	if (!output->layer_surface) {
+		return;
+	}
+	zwlr_layer_surface_v1_destroy(output->layer_surface);
+	wl_surface_attach(output->surface, NULL, 0, 0); // detach buffer
+	output->layer_surface = NULL;
+	output->height = 0;
+	output->width = 0;
+	output->frame_scheduled = false;
+}
+
+bool determine_bar_visibility(struct swaybar *bar, bool moving_layer) {
+	struct swaybar_config *config = bar->config;
+	bool visible = !(strcmp(config->mode, "invisible") == 0 ||
+		(strcmp(config->mode, config->hidden_state) == 0 // both "hide"
+			&& !bar->visible_by_modifier && !bar->visible_by_urgency));
+
+	struct swaybar_output *output;
+	if (visible == bar->visible) {
+		if (visible && moving_layer) {
+			// need to destroy layer surface to move to a different layer
+			wl_list_for_each(output, &bar->outputs, link) {
+				destroy_layer_surface(output);
+				add_layer_surface(output);
+			}
+		}
+	} else {
+		bar->visible = visible;
+		wl_list_for_each(output, &bar->outputs, link) {
+			if (visible) {
+				add_layer_surface(output);
+			} else {
+				destroy_layer_surface(output);
+			}
+		}
+	}
+	return visible;
 }
 
 static bool bar_uses_output(struct swaybar *bar, const char *name) {
@@ -423,8 +468,11 @@ static void xdg_output_handle_done(void *data,
 		wl_list_remove(&output->link);
 		wl_list_insert(&bar->outputs, &output->link);
 
-		add_layer_surface(output);
+		output->surface = wl_compositor_create_surface(bar->compositor);
-		set_output_dirty(output);
+		assert(output->surface);
+		if (bar->visible) {
+			add_layer_surface(output);
+		}
 	}
 }
 

swaybar/config.c

@@ -30,7 +30,8 @@ struct swaybar_config *init_config(void) {
 	config->pango_markup = false;
 	config->position = parse_position("bottom");
 	config->font = strdup("monospace 10");
-	config->mode = NULL;
+	config->mode = strdup("dock");
+	config->hidden_state = strdup("hide");
 	config->sep_symbol = NULL;
 	config->strip_workspace_numbers = false;
 	config->binding_mode_indicator = true;
@@ -84,6 +85,7 @@ void free_config(struct swaybar_config *config) {
 	free(config->status_command);
 	free(config->font);
 	free(config->mode);
+	free(config->hidden_state);
 	free(config->sep_symbol);
 	for (int i = 0; i < config->bindings->length; i++) {
 		struct swaybar_binding *binding = config->bindings->items[i];

swaybar/ipc.c

@@ -152,12 +152,12 @@ static bool ipc_parse_config(
 		json_object_put(bar_config);
 		return false;
 	}
-	json_object *markup, *mode, *hidden_bar, *position, *status_command;
+	json_object *markup, *mode, *hidden_state, *position, *status_command;
 	json_object *font, *bar_height, *wrap_scroll, *workspace_buttons, *strip_workspace_numbers;
 	json_object *binding_mode_indicator, *verbose, *colors, *sep_symbol, *outputs;
 	json_object *bindings;
 	json_object_object_get_ex(bar_config, "mode", &mode);
-	json_object_object_get_ex(bar_config, "hidden_bar", &hidden_bar);
+	json_object_object_get_ex(bar_config, "hidden_state", &hidden_state);
 	json_object_object_get_ex(bar_config, "position", &position);
 	json_object_object_get_ex(bar_config, "status_command", &status_command);
 	json_object_object_get_ex(bar_config, "font", &font);
@@ -220,6 +220,14 @@ static bool ipc_parse_config(
 			list_add(config->bindings, binding);
 		}
 	}
+	if (hidden_state) {
+		free(config->hidden_state);
+		config->hidden_state = strdup(json_object_get_string(hidden_state));
+	}
+	if (mode) {
+		free(config->mode);
+		config->mode = strdup(json_object_get_string(mode));
+	}
 
 	struct config_output *output, *tmp;
 	wl_list_for_each_safe(output, tmp, &config->outputs, link) {
@@ -367,6 +375,37 @@ bool ipc_initialize(struct swaybar *bar) {
 	return true;
 }
 
+static bool handle_barconfig_update(struct swaybar *bar,
+		json_object *json_config) {
+	json_object *json_id;
+	json_object_object_get_ex(json_config, "id", &json_id);
+	const char *id = json_object_get_string(json_id);
+	if (strcmp(id, bar->id) != 0) {
+		return false;
+	}
+
+	struct swaybar_config *config = bar->config;
+
+	json_object *json_state;
+	json_object_object_get_ex(json_config, "hidden_state", &json_state);
+	const char *new_state = json_object_get_string(json_state);
+	char *old_state = config->hidden_state;
+	if (strcmp(new_state, old_state) != 0) {
+		wlr_log(WLR_DEBUG, "Changing bar hidden state to %s", new_state);
+		free(old_state);
+		config->hidden_state = strdup(new_state);
+		return determine_bar_visibility(bar, false);
+	}
+
+	free(config->mode);
+	json_object *json_mode;
+	json_object_object_get_ex(json_config, "mode", &json_mode);
+	config->mode = strdup(json_object_get_string(json_mode));
+	wlr_log(WLR_DEBUG, "Changing bar mode to %s", config->mode);
+
+	return determine_bar_visibility(bar, true);
+}
+
 bool handle_ipc_readable(struct swaybar *bar) {
 	struct ipc_response *resp = ipc_recv_response(bar->ipc_event_socketfd);
 	if (!resp) {
@@ -402,6 +441,9 @@ bool handle_ipc_readable(struct swaybar *bar) {
 		}
 		break;
 	}
+	case IPC_EVENT_BARCONFIG_UPDATE:
+		bar_is_dirty = handle_barconfig_update(bar, result);
+		break;
 	default:
 		bar_is_dirty = false;
 		break;

swaybar/render.c

@@ -494,6 +494,9 @@ static const struct wl_callback_listener output_frame_listener = {
 
 void render_frame(struct swaybar_output *output) {
 	assert(output->surface != NULL);
+	if (!output->layer_surface) {
+		return;
+	}
 
 	free_hotspots(&output->hotspots);
 
@@ -519,7 +522,9 @@ void render_frame(struct swaybar_output *output) {
 	if (height != output->height) {
 		// Reconfigure surface
 		zwlr_layer_surface_v1_set_size(output->layer_surface, 0, height);
-		zwlr_layer_surface_v1_set_exclusive_zone(output->layer_surface, height);
+		if (strcmp(output->bar->config->mode, "dock") == 0) {
+			zwlr_layer_surface_v1_set_exclusive_zone(output->layer_surface, height);
+		}
 		// TODO: this could infinite loop if the compositor assigns us a
 		// different height than what we asked for
 		wl_surface_commit(output->surface);