swaybar: rewrite protocol determination

This now uses the getline function to receive the header, replacing
read_line_buffer, which has been deleted since it is otherwise unused.
Furthermore, once the protocol has been determined, the current status
is handled immediately to be shown (though this has not been added for
the i3bar protocol since it has not yet been rewritten to handle this).

common/readline.c

@@ -70,28 +70,3 @@ char *peek_line(FILE *file, int line_offset, long *position) {
 	fseek(file, pos, SEEK_SET);
 	return line;
 }
-
-char *read_line_buffer(FILE *file, char *string, size_t string_len) {
-	size_t length = 0;
-	if (!string) {
-		return NULL;
-	}
-	while (1) {
-		int c = getc(file);
-		if (c == EOF || c == '\n' || c == '\0') {
-			break;
-		}
-		if (c == '\r') {
-			continue;
-		}
-		string[length++] = c;
-		if (string_len <= length) {
-			return NULL;
-		}
-	}
-	if (length + 1 == string_len) {
-		return NULL;
-	}
-	string[length] = '\0';
-	return string;
-}

swaybar/status_line.c

@@ -31,7 +31,6 @@ void status_error(struct status_line *status, const char *text) {
 
 bool status_handle_readable(struct status_line *status) {
 	ssize_t read_bytes = 1;
-	char *line;
 	switch (status->protocol) {
 	case PROTOCOL_I3BAR:
 		if (i3bar_handle_readable(status) > 0) {
@@ -39,36 +38,37 @@ bool status_handle_readable(struct status_line *status) {
 		}
 		break;
 	case PROTOCOL_UNDEF:
-		line = read_line_buffer(status->read,
-				status->buffer, status->buffer_size);
-		if (!line) {
+		errno = 0;
+		read_bytes = getline(&status->buffer,
+				&status->buffer_size, status->read);
+		if (errno == EAGAIN) {
+			clearerr(status->read);
+		} else if (errno) {
 			status_error(status, "[error reading from status command]");
-			return false;
+			return true;
 		}
-		if (line[0] == '{') {
-			json_object *proto = json_tokener_parse(line);
-			if (proto) {
-				json_object *version;
-				if (json_object_object_get_ex(proto, "version", &version)
-							&& json_object_get_int(version) == 1) {
-					wlr_log(WLR_DEBUG, "Switched to i3bar protocol.");
-					status->protocol = PROTOCOL_I3BAR;
-				}
-				json_object *click_events;
-				if (json_object_object_get_ex(
-							proto, "click_events", &click_events)
-						&& json_object_get_boolean(click_events)) {
-					wlr_log(WLR_DEBUG, "Enabled click events.");
-					status->i3bar_state.click_events = true;
-					const char *events_array = "[\n";
-					ssize_t len = strlen(events_array);
-					if (write(status->write_fd, events_array, len) != len) {
-						status_error(status,
-								"[failed to write to status command]");
-					}
+
+		// the header must be sent completely the first time round
+		json_object *header, *version;
+		if (status->buffer[read_bytes - 1] == '\n'
+				&& (header = json_tokener_parse(status->buffer))
+				&& json_object_object_get_ex(header, "version", &version)
+				&& json_object_get_int(version) == 1) {
+			wlr_log(WLR_DEBUG, "Using i3bar protocol.");
+			status->protocol = PROTOCOL_I3BAR;
+
+			json_object *click_events;
+			if (json_object_object_get_ex(header, "click_events", &click_events)
+					&& json_object_get_boolean(click_events)) {
+				wlr_log(WLR_DEBUG, "Enabling click events.");
+				status->i3bar_state.click_events = true;
+				if (write(status->write_fd, "[\n", 2) != 2) {
+					status_error(status, "[failed to write to status command]");
+					json_object_put(header);
+					return true;
 				}
-				json_object_put(proto);
 			}
+			json_object_put(header);
 
 			status->protocol = PROTOCOL_I3BAR;
 			free(status->buffer);
@@ -76,11 +76,13 @@ bool status_handle_readable(struct status_line *status) {
 			status->i3bar_state.buffer_size = 4096;
 			status->i3bar_state.buffer =
 				malloc(status->i3bar_state.buffer_size);
-		} else {
-			status->protocol = PROTOCOL_TEXT;
-			status->text = line;
+			return false;
 		}
-		return true;
+
+		wlr_log(WLR_DEBUG, "Using text protocol.");
+		status->protocol = PROTOCOL_TEXT;
+		status->text = status->buffer;
+		// intentional fall-through
 	case PROTOCOL_TEXT:
 		errno = 0;
 		while (true) {