swaybg: one instance for all outputs

This makes it so there will only be one swaybg instance running
instead of one per output. swaybg's cli has been changed to a xrandr
like interface, where you select an output and then change properties
for that output and then select another output and repeat. This also
makes it so swaybg is only killed and respawned when a background
changes or when reloading.

5 files changed, 157 insertions, 110 deletions

diff --git a/sway/commands/output.c b/sway/commands/output.c
index 44e28512..6b9eafdb 100644
--- a/sway/commands/output.c
+++ b/sway/commands/output.c
@@ -68,6 +68,8 @@ struct cmd_results *cmd_output(int argc, char **argv) {
 	config->handler_context.leftovers.argc = 0;
 	config->handler_context.leftovers.argv = NULL;
 
+	bool background = output->background;
+
 	output = store_output_config(output);
 
 	// If reloading, the output configs will be applied after reading the
@@ -75,6 +77,9 @@ struct cmd_results *cmd_output(int argc, char **argv) {
 	// workspace name is not given to re-enabled outputs.
 	if (!config->reloading) {
 		apply_output_config_to_outputs(output);
+		if (background) {
+			spawn_swaybg();
+		}
 	}
 
 	return cmd_results_new(CMD_SUCCESS, NULL);
diff --git a/sway/config.c b/sway/config.c
index 7104f55d..d5bfe105 100644
--- a/sway/config.c
+++ b/sway/config.c
@@ -104,6 +104,9 @@ void free_config(struct sway_config *config) {
 		}
 		list_free(config->output_configs);
 	}
+	if (config->swaybg_client != NULL) {
+		wl_client_destroy(config->swaybg_client);
+	}
 	if (config->input_configs) {
 		for (int i = 0; i < config->input_configs->length; i++) {
 			free_input_config(config->input_configs->items[i]);
@@ -480,6 +483,7 @@ bool load_main_config(const char *file, bool is_active, bool validating) {
 
 	if (is_active) {
 		reset_outputs();
+		spawn_swaybg();
 
 		config->reloading = false;
 		if (config->swaynag_config_errors.pid > 0) {
diff --git a/sway/config/output.c b/sway/config/output.c
index d06051b3..0473d0ad 100644
--- a/sway/config/output.c
+++ b/sway/config/output.c
@@ -228,91 +228,6 @@ static bool set_mode(struct wlr_output *output, int width, int height,
 	return wlr_output_set_mode(output, best);
 }
 
-static void handle_swaybg_client_destroy(struct wl_listener *listener,
-		void *data) {
-	struct sway_output *output =
-		wl_container_of(listener, output, swaybg_client_destroy);
-	wl_list_remove(&output->swaybg_client_destroy.link);
-	wl_list_init(&output->swaybg_client_destroy.link);
-	output->swaybg_client = NULL;
-}
-
-static bool set_cloexec(int fd, bool cloexec) {
-	int flags = fcntl(fd, F_GETFD);
-	if (flags == -1) {
-		sway_log_errno(SWAY_ERROR, "fcntl failed");
-		return false;
-	}
-	if (cloexec) {
-		flags = flags | FD_CLOEXEC;
-	} else {
-		flags = flags & ~FD_CLOEXEC;
-	}
-	if (fcntl(fd, F_SETFD, flags) == -1) {
-		sway_log_errno(SWAY_ERROR, "fcntl failed");
-		return false;
-	}
-	return true;
-}
-
-static bool spawn_swaybg(struct sway_output *output, char *const cmd[]) {
-	int sockets[2];
-	if (socketpair(AF_UNIX, SOCK_STREAM, 0, sockets) != 0) {
-		sway_log_errno(SWAY_ERROR, "socketpair failed");
-		return false;
-	}
-	if (!set_cloexec(sockets[0], true) || !set_cloexec(sockets[1], true)) {
-		return false;
-	}
-
-	output->swaybg_client = wl_client_create(server.wl_display, sockets[0]);
-	if (output->swaybg_client == NULL) {
-		sway_log_errno(SWAY_ERROR, "wl_client_create failed");
-		return false;
-	}
-
-	output->swaybg_client_destroy.notify = handle_swaybg_client_destroy;
-	wl_client_add_destroy_listener(output->swaybg_client,
-		&output->swaybg_client_destroy);
-
-	pid_t pid = fork();
-	if (pid < 0) {
-		sway_log_errno(SWAY_ERROR, "fork failed");
-		return false;
-	} else if (pid == 0) {
-		pid = fork();
-		if (pid < 0) {
-			sway_log_errno(SWAY_ERROR, "fork failed");
-			_exit(EXIT_FAILURE);
-		} else if (pid == 0) {
-			if (!set_cloexec(sockets[1], false)) {
-				_exit(EXIT_FAILURE);
-			}
-
-			char wayland_socket_str[16];
-			snprintf(wayland_socket_str, sizeof(wayland_socket_str),
-				"%d", sockets[1]);
-			setenv("WAYLAND_SOCKET", wayland_socket_str, true);
-
-			execvp(cmd[0], cmd);
-			sway_log_errno(SWAY_ERROR, "execvp failed");
-			_exit(EXIT_FAILURE);
-		}
-		_exit(EXIT_SUCCESS);
-	}
-
-	if (close(sockets[1]) != 0) {
-		sway_log_errno(SWAY_ERROR, "close failed");
-		return false;
-	}
-	if (waitpid(pid, NULL, 0) < 0) {
-		sway_log_errno(SWAY_ERROR, "waitpid failed");
-		return false;
-	}
-
-	return true;
-}
-
 bool apply_output_config(struct output_config *oc, struct sway_output *output) {
 	if (output == root->noop_output) {
 		return false;
@@ -397,25 +312,6 @@ bool apply_output_config(struct output_config *oc, struct sway_output *output) {
 	wlr_output_transformed_resolution(wlr_output,
 		&output->width, &output->height);
 
-	if (output->swaybg_client != NULL) {
-		wl_client_destroy(output->swaybg_client);
-	}
-	if (oc && oc->background && config->swaybg_command) {
-		sway_log(SWAY_DEBUG, "Setting background for output %s to %s",
-			wlr_output->name, oc->background);
-
-		char *const cmd[] = {
-			config->swaybg_command,
-			wlr_output->name,
-			oc->background,
-			oc->background_option,
-			oc->background_fallback ? oc->background_fallback : NULL,
-			NULL,
-		};
-		if (!spawn_swaybg(output, cmd)) {
-			return false;
-		}
-	}
 
 	if (oc && oc->dpms_state == DPMS_OFF) {
 		sway_log(SWAY_DEBUG, "Turning off screen");
@@ -584,3 +480,151 @@ void free_output_config(struct output_config *oc) {
 	free(oc->background_option);
 	free(oc);
 }
+
+static void handle_swaybg_client_destroy(struct wl_listener *listener,
+		void *data) {
+	wl_list_remove(&config->swaybg_client_destroy.link);
+	wl_list_init(&config->swaybg_client_destroy.link);
+	config->swaybg_client = NULL;
+}
+
+static bool set_cloexec(int fd, bool cloexec) {
+	int flags = fcntl(fd, F_GETFD);
+	if (flags == -1) {
+		sway_log_errno(SWAY_ERROR, "fcntl failed");
+		return false;
+	}
+	if (cloexec) {
+		flags = flags | FD_CLOEXEC;
+	} else {
+		flags = flags & ~FD_CLOEXEC;
+	}
+	if (fcntl(fd, F_SETFD, flags) == -1) {
+		sway_log_errno(SWAY_ERROR, "fcntl failed");
+		return false;
+	}
+	return true;
+}
+
+static bool _spawn_swaybg(char **command) {
+	if (config->swaybg_client != NULL) {
+		wl_client_destroy(config->swaybg_client);
+	}
+	int sockets[2];
+	if (socketpair(AF_UNIX, SOCK_STREAM, 0, sockets) != 0) {
+		sway_log_errno(SWAY_ERROR, "socketpair failed");
+		return false;
+	}
+	if (!set_cloexec(sockets[0], true) || !set_cloexec(sockets[1], true)) {
+		return false;
+	}
+
+	config->swaybg_client = wl_client_create(server.wl_display, sockets[0]);
+	if (config->swaybg_client == NULL) {
+		sway_log_errno(SWAY_ERROR, "wl_client_create failed");
+		return false;
+	}
+
+	config->swaybg_client_destroy.notify = handle_swaybg_client_destroy;
+	wl_client_add_destroy_listener(config->swaybg_client,
+		&config->swaybg_client_destroy);
+
+	pid_t pid = fork();
+	if (pid < 0) {
+		sway_log_errno(SWAY_ERROR, "fork failed");
+		return false;
+	} else if (pid == 0) {
+		pid = fork();
+		if (pid < 0) {
+			sway_log_errno(SWAY_ERROR, "fork failed");
+			_exit(EXIT_FAILURE);
+		} else if (pid == 0) {
+			if (!set_cloexec(sockets[1], false)) {
+				_exit(EXIT_FAILURE);
+			}
+
+			char wayland_socket_str[16];
+			snprintf(wayland_socket_str, sizeof(wayland_socket_str),
+				"%d", sockets[1]);
+			setenv("WAYLAND_SOCKET", wayland_socket_str, true);
+
+			execvp(command[0], command);
+			sway_log_errno(SWAY_ERROR, "execvp failed");
+			_exit(EXIT_FAILURE);
+		}
+		_exit(EXIT_SUCCESS);
+	}
+
+	if (close(sockets[1]) != 0) {
+		sway_log_errno(SWAY_ERROR, "close failed");
+		return false;
+	}
+	if (waitpid(pid, NULL, 0) < 0) {
+		sway_log_errno(SWAY_ERROR, "waitpid failed");
+		return false;
+	}
+
+	return true;
+}
+
+bool spawn_swaybg(void) {
+	if (!config->swaybg_command) {
+		return true;
+	}
+
+	size_t length = 2;
+	for (int i = 0; i < config->output_configs->length; i++) {
+		struct output_config *oc = config->output_configs->items[i];
+		if (!oc->background) {
+			continue;
+		}
+		if (strcmp(oc->background_option, "solid_color") == 0) {
+			length += 4;
+		} else if (oc->background_fallback) {
+			length += 8;
+		} else {
+			length += 6;
+		}
+	}
+
+	char **cmd = calloc(1, sizeof(char **) * length);
+	if (!cmd) {
+		sway_log(SWAY_ERROR, "Failed to allocate spawn_swaybg command");
+		return false;
+	}
+
+	size_t i = 0;
+	cmd[i++] = config->swaybg_command;
+	for (int j = 0; j < config->output_configs->length; j++) {
+		struct output_config *oc = config->output_configs->items[j];
+		if (!oc->background) {
+			continue;
+		}
+		if (strcmp(oc->background_option, "solid_color") == 0) {
+			cmd[i++] = "-o";
+			cmd[i++] = oc->name;
+			cmd[i++] = "-c";
+			cmd[i++] = oc->background;
+		} else {
+			cmd[i++] = "-o";
+			cmd[i++] = oc->name;
+			cmd[i++] = "-i";
+			cmd[i++] = oc->background;
+			cmd[i++] = "-m";
+			cmd[i++] = oc->background_option;
+			if (oc->background_fallback) {
+				cmd[i++] = "-c";
+				cmd[i++] = oc->background_fallback;
+			}
+		}
+		assert(i <= length);
+	}
+
+	for (size_t k = 0; k < i; k++) {
+		sway_log(SWAY_DEBUG, "spawn_swaybg cmd[%ld] = %s", k, cmd[k]);
+	}
+
+	bool result = _spawn_swaybg(cmd);
+	free(cmd);
+	return result;
+}
diff --git a/sway/desktop/output.c b/sway/desktop/output.c
index 9d0c0ef5..0b3e1edb 100644
--- a/sway/desktop/output.c
+++ b/sway/desktop/output.c
@@ -525,7 +525,6 @@ static void handle_destroy(struct wl_listener *listener, void *data) {
 	wl_list_remove(&output->present.link);
 	wl_list_remove(&output->damage_destroy.link);
 	wl_list_remove(&output->damage_frame.link);
-	wl_list_remove(&output->swaybg_client_destroy.link);
 
 	transaction_commit_dirty();
 }
@@ -632,7 +631,6 @@ void handle_new_output(struct wl_listener *listener, void *data) {
 	output->damage_frame.notify = damage_handle_frame;
 	wl_signal_add(&output->damage->events.destroy, &output->damage_destroy);
 	output->damage_destroy.notify = damage_handle_destroy;
-	wl_list_init(&output->swaybg_client_destroy.link);
 
 	struct output_config *oc = find_output_config(output);
 	if (!oc || oc->enabled) {
diff --git a/sway/tree/output.c b/sway/tree/output.c
index b3589be5..24adc08d 100644
--- a/sway/tree/output.c
+++ b/sway/tree/output.c
@@ -262,10 +262,6 @@ void output_disable(struct sway_output *output) {
 
 	root_for_each_container(untrack_output, output);
 
-	if (output->swaybg_client != NULL) {
-		wl_client_destroy(output->swaybg_client);
-	}
-
 	int index = list_find(root->outputs, output);
 	list_del(root->outputs, index);