seat fallback config

include/sway/commands.h

@@ -198,6 +198,7 @@ sway_cmd input_cmd_xkb_options;
 sway_cmd input_cmd_xkb_rules;
 sway_cmd input_cmd_xkb_variant;
 
+sway_cmd seat_cmd_fallback;
 sway_cmd seat_cmd_attach;
 
 sway_cmd cmd_ipc_cmd;

include/sway/config.h

@@ -90,6 +90,7 @@ struct seat_attachment_config {
  */
 struct seat_config {
 	char *name;
+	int fallback; // -1 means not set
 	list_t *attachments; // list of seat_attachment configs
 };
 

sway/commands.c

@@ -165,6 +165,7 @@ static struct cmd_handler input_handlers[] = {
 // must be in order for the bsearch
 static struct cmd_handler seat_handlers[] = {
 	{ "attach", seat_cmd_attach },
+	{ "fallback", seat_cmd_fallback },
 };
 
 static struct cmd_handler *find_handler(char *line, enum cmd_status block) {

sway/commands/seat.c

@@ -24,6 +24,8 @@ struct cmd_results *cmd_seat(int argc, char **argv) {
 		current_seat_config = new_seat_config(argv[0]);
 		if (strcasecmp("attach", argv[1]) == 0) {
 			res = seat_cmd_attach(argc_new, argv_new);
+		} else if (strcasecmp("fallback", argv[1]) == 0) {
+			res = seat_cmd_fallback(argc_new, argv_new);
 		} else {
 			res = cmd_results_new(CMD_INVALID, "seat <name>", "Unknown command %s", argv[1]);
 		}

sway/commands/seat/fallback.c

@@ -0,0 +1,29 @@
+#include <string.h>
+#include <strings.h>
+#include "sway/config.h"
+#include "sway/commands.h"
+#include "sway/input/input-manager.h"
+
+struct cmd_results *seat_cmd_fallback(int argc, char **argv) {
+	struct cmd_results *error = NULL;
+	if ((error = checkarg(argc, "fallback", EXPECTED_AT_LEAST, 1))) {
+		return error;
+	}
+	if (!current_seat_config) {
+		return cmd_results_new(CMD_FAILURE, "fallback", "No seat defined");
+	}
+	struct seat_config *new_config =
+		new_seat_config(current_seat_config->name);
+
+	if (strcasecmp(argv[0], "true") == 0) {
+		new_config->fallback = 1;
+	} else if (strcasecmp(argv[0], "false") == 0) {
+		new_config->fallback = 0;
+	} else {
+		return cmd_results_new(CMD_INVALID, "fallback",
+			"Expected 'fallback <true|false>'");
+	}
+
+	apply_seat_config(new_config);
+	return cmd_results_new(CMD_SUCCESS, NULL, NULL);
+}

sway/config/seat.c

@@ -17,6 +17,7 @@ struct seat_config *new_seat_config(const char* name) {
 		return NULL;
 	}
 
+	seat->fallback = -1;
 	seat->attachments = create_list();
 	if (!sway_assert(seat->attachments,
 				"could not allocate seat attachments list")) {
@@ -66,6 +67,10 @@ void merge_seat_config(struct seat_config *dest, struct seat_config *source) {
 		dest->name = strdup(source->name);
 	}
 
+	if (source->fallback != -1) {
+		dest->fallback = source->fallback;
+	}
+
 	for (int i = 0; i < source->attachments->length; ++i) {
 		struct seat_attachment_config *source_attachment =
 			source->attachments->items[i];

sway/input/input-manager.c

@@ -151,13 +151,30 @@ static void input_add_notify(struct wl_listener *listener, void *data) {
 		return;
 	}
 
+	bool added = false;
 	wl_list_for_each(seat, &input->seats, link) {
 		if (seat->config &&
 				(seat_config_get_attachment(seat->config, input_device->identifier) ||
 				seat_config_get_attachment(seat->config, "*"))) {
 			sway_seat_add_device(seat, input_device);
+			added = true;
 		}
 	}
+
+	if (!added) {
+		wl_list_for_each(seat, &input->seats, link) {
+			if (seat->config && seat->config->fallback == 1) {
+				sway_seat_add_device(seat, input_device);
+				added = true;
+			}
+		}
+	}
+
+	if (!added) {
+		sway_log(L_DEBUG,
+			"device '%s' is not configured on any seats",
+			input_device->identifier);
+	}
 }
 
 static void input_remove_notify(struct wl_listener *listener, void *data) {
@@ -248,35 +265,53 @@ void sway_input_manager_apply_seat_config(struct sway_input_manager *input,
 		struct seat_config *seat_config) {
 	sway_log(L_DEBUG, "applying new seat config for seat %s", seat_config->name);
 	struct sway_seat *seat = input_manager_get_seat(input, seat_config->name);
-	// the old config is invalid so clear it
-	sway_seat_set_config(seat, NULL);
+	if (!seat) {
+		return;
+	}
 
-	// clear devices
+	sway_seat_set_config(seat, seat_config);
+
+	// for every device, try to add it to a seat and if no seat has it
+	// attached, add it to the fallback seats.
 	struct sway_input_device *input_device = NULL;
 	wl_list_for_each(input_device, &input->devices, link) {
-		sway_seat_remove_device(seat, input_device);
+		list_t *seat_list = create_list();
+		struct sway_seat *seat = NULL;
+		wl_list_for_each(seat, &input->seats, link) {
+			if (!seat->config) {
+				continue;
+			}
+			if (seat_config_get_attachment(seat->config, "*") ||
+					seat_config_get_attachment(seat->config, input_device->identifier)) {
+				list_add(seat_list, seat);
+			}
 		}
 
-	if (seat_config_get_attachment(seat_config, "*")) {
-		wl_list_for_each(input_device, &input->devices, link) {
+		if (seat_list->length) {
+			wl_list_for_each(seat, &input->seats, link) {
+				bool attached = false;
+				for (int i = 0; i < seat_list->length; ++i) {
+					if (seat == seat_list->items[i]) {
+						attached = true;
+						break;
+					}
+				}
+				if (attached) {
 					sway_seat_add_device(seat, input_device);
+				} else {
+					sway_seat_remove_device(seat, input_device);
+				}
 			}
 		} else {
-		for (int i = 0; i < seat_config->attachments->length; ++i) {
-			struct seat_attachment_config *attachment =
-				seat_config->attachments->items[i];
-
-			struct sway_input_device *device =
-				input_sway_device_from_identifier(input,
-					attachment->identifier);
-
-			if (device) {
-				sway_seat_add_device(seat, device);
+			wl_list_for_each(seat, &input->seats, link) {
+				if (seat->config && seat->config->fallback == 1) {
+					sway_seat_add_device(seat, input_device);
+				} else {
+					sway_seat_remove_device(seat, input_device);
+				}
 			}
 		}
 	}
-
-	sway_seat_set_config(seat, seat_config);
 }
 
 void sway_input_manager_configure_xcursor(struct sway_input_manager *input) {

sway/input/seat.c

@@ -120,6 +120,7 @@ void sway_seat_configure_device(struct sway_seat *seat,
 void sway_seat_add_device(struct sway_seat *seat,
 		struct sway_input_device *input_device) {
 	if (sway_seat_get_device(seat, input_device)) {
+		sway_seat_configure_device(seat, input_device);
 		return;
 	}
 
@@ -246,7 +247,5 @@ void sway_seat_set_config(struct sway_seat *seat,
 		seat_device->attachment_config =
 			seat_config_get_attachment(seat_config,
 				seat_device->input_device->identifier);
-		sway_seat_configure_device(seat, seat_device->input_device);
 	}
-
 }

sway/meson.build

@@ -13,6 +13,7 @@ sway_sources = files(
 	'commands/input.c',
 	'commands/seat.c',
 	'commands/seat/attach.c',
+	'commands/seat/fallback.c',
 	'commands/input/accel_profile.c',
 	'commands/input/click_method.c',
 	'commands/input/drag_lock.c',