swaybar: handle hotplugging

Don't kill and respawn swaybars on hotplug.

include/sway/config.h

@@ -512,9 +512,7 @@ void free_sway_binding(struct sway_binding *sb);
 
 void seat_execute_command(struct sway_seat *seat, struct sway_binding *binding);
 
-void load_swaybars();
-
-void invoke_swaybar(struct bar_config *bar);
+void load_swaybars(void);
 
 void terminate_swaybg(pid_t pid);
 

sway/config/bar.c

@@ -165,7 +165,7 @@ cleanup:
 	return NULL;
 }
 
-void invoke_swaybar(struct bar_config *bar) {
+static void invoke_swaybar(struct bar_config *bar) {
 	// Pipe to communicate errors
 	int filedes[2];
 	if (pipe(filedes) == -1) {
@@ -219,27 +219,13 @@ void invoke_swaybar(struct bar_config *bar) {
 	close(filedes[1]);
 }
 
-void load_swaybars() {
+void load_swaybars(void) {
 	for (int i = 0; i < config->bars->length; ++i) {
 		struct bar_config *bar = config->bars->items[i];
-		bool apply = false;
-		if (bar->outputs) {
-			for (int j = 0; j < bar->outputs->length; ++j) {
-				char *o = bar->outputs->items[j];
-				if (!strcmp(o, "*") || output_by_name(o)) {
-					apply = true;
-					break;
-				}
-			}
-		} else {
-			apply = true;
-		}
-		if (apply) {
-			if (bar->pid != 0) {
-				terminate_swaybar(bar->pid);
-			}
-			wlr_log(WLR_DEBUG, "Invoking swaybar for bar id '%s'", bar->id);
-			invoke_swaybar(bar);
+		if (bar->pid != 0) {
+			terminate_swaybar(bar->pid);
 		}
+		wlr_log(WLR_DEBUG, "Invoking swaybar for bar id '%s'", bar->id);
+		invoke_swaybar(bar);
 	}
 }

sway/main.c

@@ -424,6 +424,7 @@ int main(int argc, char **argv) {
 	}
 
 	config->active = true;
+	load_swaybars();
 	// Execute commands until there are none left
 	wlr_log(WLR_DEBUG, "Running deferred commands");
 	while (config->cmd_queue->length) {

sway/tree/output.c

@@ -109,8 +109,6 @@ void output_enable(struct sway_output *output, struct output_config *oc) {
 
 	wl_signal_emit(&root->events.new_node, &output->node);
 
-	load_swaybars();
-
 	arrange_layers(output);
 	arrange_root();
 }

swaybar/bar.c

@@ -48,8 +48,13 @@ static void swaybar_output_free(struct swaybar_output *output) {
 		return;
 	}
 	wlr_log(WLR_DEBUG, "Removing output %s", output->name);
-	zwlr_layer_surface_v1_destroy(output->layer_surface);
-	wl_surface_destroy(output->surface);
+	if (output->layer_surface != NULL) {
+		zwlr_layer_surface_v1_destroy(output->layer_surface);
+	}
+	if (output->surface != NULL) {
+		wl_surface_destroy(output->surface);
+	}
+	zxdg_output_v1_destroy(output->xdg_output);
 	wl_output_destroy(output->output);
 	destroy_buffer(&output->buffers[0]);
 	destroy_buffer(&output->buffers[1]);
@@ -283,6 +288,37 @@ const struct wl_seat_listener seat_listener = {
 	.name = seat_handle_name,
 };
 
+static void add_layer_surface(struct swaybar_output *output) {
+	if (output->surface != NULL) {
+		return;
+	}
+	struct swaybar *bar = output->bar;
+
+	output->surface = wl_compositor_create_surface(bar->compositor);
+	assert(output->surface);
+	output->layer_surface = zwlr_layer_shell_v1_get_layer_surface(
+			bar->layer_shell, output->surface, output->output,
+			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);
+}
+
+static bool bar_uses_output(struct swaybar *bar, const char *name) {
+	if (bar->config->all_outputs) {
+		return true;
+	}
+	struct config_output *coutput;
+	wl_list_for_each(coutput, &bar->config->outputs, link) {
+		if (strcmp(coutput->name, name) == 0) {
+			return true;
+		}
+	}
+	return false;
+}
+
 static void output_geometry(void *data, struct wl_output *output, int32_t x,
 		int32_t y, int32_t width_mm, int32_t height_mm, int32_t subpixel,
 		const char *make, const char *model, int32_t transform) {
@@ -326,7 +362,22 @@ static void xdg_output_handle_logical_size(void *data,
 
 static void xdg_output_handle_done(void *data,
 		struct zxdg_output_v1 *xdg_output) {
-	// Who cares
+	struct swaybar_output *output = data;
+	struct swaybar *bar = output->bar;
+
+	assert(output->name != NULL);
+	if (!bar_uses_output(bar, output->name)) {
+		swaybar_output_free(output);
+		return;
+	}
+
+	if (wl_list_empty(&output->link)) {
+		wl_list_remove(&output->link);
+		wl_list_insert(&bar->outputs, &output->link);
+
+		add_layer_surface(output);
+		render_frame(bar, output);
+	}
 }
 
 static void xdg_output_handle_name(void *data,
@@ -349,17 +400,15 @@ struct zxdg_output_v1_listener xdg_output_listener = {
 	.description = xdg_output_handle_description,
 };
 
-static bool bar_uses_output(struct swaybar *bar, const char *name) {
-	if (bar->config->all_outputs) {
-		return true;
+static void add_xdg_output(struct swaybar_output *output) {
+	if (output->xdg_output != NULL) {
+		return;
 	}
-	struct config_output *coutput;
-	wl_list_for_each(coutput, &bar->config->outputs, link) {
-		if (strcmp(coutput->name, name) == 0) {
-			return true;
-		}
-	}
-	return false;
+	assert(output->bar->xdg_output_manager != NULL);
+	output->xdg_output = zxdg_output_manager_v1_get_xdg_output(
+		output->bar->xdg_output_manager, output->output);
+	zxdg_output_v1_add_listener(output->xdg_output, &xdg_output_listener,
+		output);
 }
 
 static void handle_global(void *data, struct wl_registry *registry,
@@ -386,7 +435,10 @@ static void handle_global(void *data, struct wl_registry *registry,
 		output->wl_name = name;
 		wl_list_init(&output->workspaces);
 		wl_list_init(&output->hotspots);
-		wl_list_insert(&bar->outputs, &output->link);
+		wl_list_init(&output->link);
+		if (bar->xdg_output_manager != NULL) {
+			add_xdg_output(output);
+		}
 	} else if (strcmp(interface, zwlr_layer_shell_v1_interface.name) == 0) {
 		bar->layer_shell = wl_registry_bind(
 				registry, name, &zwlr_layer_shell_v1_interface, 1);
@@ -416,7 +468,9 @@ static const struct wl_registry_listener registry_listener = {
 static void render_all_frames(struct swaybar *bar) {
 	struct swaybar_output *output;
 	wl_list_for_each(output, &bar->outputs, link) {
-		render_frame(bar, output);
+		if (output->surface != NULL) {
+			render_frame(bar, output);
+		}
 	}
 }
 
@@ -443,23 +497,10 @@ void bar_setup(struct swaybar *bar,
 
 	struct swaybar_output *output;
 	wl_list_for_each(output, &bar->outputs, link) {
-		output->xdg_output = zxdg_output_manager_v1_get_xdg_output(
-			bar->xdg_output_manager, output->output);
-		zxdg_output_v1_add_listener(output->xdg_output, &xdg_output_listener,
-			output);
+		add_xdg_output(output);
 	}
 	wl_display_roundtrip(bar->display);
 
-	struct swaybar_output *output_tmp;
-	wl_list_for_each_safe(output, output_tmp, &bar->outputs, link) {
-		if (!bar_uses_output(bar, output->name)) {
-			zxdg_output_v1_destroy(output->xdg_output);
-			wl_output_destroy(output->output);
-			wl_list_remove(&output->link);
-			free(output);
-		}
-	}
-
 	struct swaybar_pointer *pointer = &bar->pointer;
 
 	int max_scale = 1;
@@ -479,18 +520,6 @@ void bar_setup(struct swaybar *bar,
 	pointer->cursor_surface = wl_compositor_create_surface(bar->compositor);
 	assert(pointer->cursor_surface);
 
-	wl_list_for_each(output, &bar->outputs, link) {
-		output->surface = wl_compositor_create_surface(bar->compositor);
-		assert(output->surface);
-		output->layer_surface = zwlr_layer_shell_v1_get_layer_surface(
-				bar->layer_shell, output->surface, output->output,
-				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);
-	}
 	ipc_get_workspaces(bar);
 	render_all_frames(bar);
 }

swaybar/render.c

@@ -1,4 +1,5 @@
 #define _POSIX_C_SOURCE 200809L
+#include <assert.h>
 #include <limits.h>
 #include <stdlib.h>
 #include <stdint.h>
@@ -480,6 +481,8 @@ static uint32_t render_to_cairo(cairo_t *cairo,
 }
 
 void render_frame(struct swaybar *bar, struct swaybar_output *output) {
+	assert(output->surface != NULL);
+
 	struct swaybar_hotspot *hotspot, *tmp;
 	wl_list_for_each_safe(hotspot, tmp, &output->hotspots, link) {
 		if (hotspot->destroy) {