From f48554d48b002ac2881569ecb088aeef710f9369 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Thomas=20Wei=C3=9Fschuh?= <thomas@t-8ch.de>
Date: Wed, 26 May 2021 13:30:31 +0200
Subject: [PATCH] libsmartcols: add support for optional boolean values
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These default to `null` instead of `false`.

Signed-off-by: Thomas Weißschuh <thomas@t-8ch.de>
---
 include/jsonwrt.h                  |  2 ++
 lib/jsonwrt.c                      |  8 ++++++++
 libsmartcols/src/libsmartcols.h.in |  3 ++-
 libsmartcols/src/print.c           | 15 ++++++++++-----
 4 files changed, 22 insertions(+), 6 deletions(-)

diff --git a/include/jsonwrt.h b/include/jsonwrt.h
index 5be2d70cd..4587b60a9 100644
--- a/include/jsonwrt.h
+++ b/include/jsonwrt.h
@@ -40,5 +40,7 @@ void ul_jsonwrt_value_u64(struct ul_jsonwrt *fmt,
 			const char *name, uint64_t data);
 void ul_jsonwrt_value_boolean(struct ul_jsonwrt *fmt,
 			const char *name, int data);
+void ul_jsonwrt_value_null(struct ul_jsonwrt *fmt,
+			const char *name);
 
 #endif /* UTIL_LINUX_JSONWRT_H */
diff --git a/lib/jsonwrt.c b/lib/jsonwrt.c
index f2003e808..9331dec0e 100644
--- a/lib/jsonwrt.c
+++ b/lib/jsonwrt.c
@@ -214,3 +214,11 @@ void ul_jsonwrt_value_boolean(struct ul_jsonwrt *fmt,
 	fputs(data ? "true" : "false", fmt->out);
 	ul_jsonwrt_value_close(fmt);
 }
+
+void ul_jsonwrt_value_null(struct ul_jsonwrt *fmt,
+			const char *name)
+{
+	ul_jsonwrt_value_open(fmt, name);
+	fputs("null", fmt->out);
+	ul_jsonwrt_value_close(fmt);
+}
diff --git a/libsmartcols/src/libsmartcols.h.in b/libsmartcols/src/libsmartcols.h.in
index 4c17eb1dc..8c4ba814e 100644
--- a/libsmartcols/src/libsmartcols.h.in
+++ b/libsmartcols/src/libsmartcols.h.in
@@ -95,7 +95,8 @@ enum {
 	SCOLS_JSON_NUMBER    = 1,
 	SCOLS_JSON_BOOLEAN   = 2,
 	SCOLS_JSON_ARRAY_STRING = 3,        /* e.g. for multi-line (SCOLS_FL_WRAP) cells */
-	SCOLS_JSON_ARRAY_NUMBER	= 4
+	SCOLS_JSON_ARRAY_NUMBER	= 4,
+	SCOLS_JSON_BOOLEAN_OPTIONAL = 5,
 };
 
 /*
diff --git a/libsmartcols/src/print.c b/libsmartcols/src/print.c
index 9f6014848..6f6d88e55 100644
--- a/libsmartcols/src/print.c
+++ b/libsmartcols/src/print.c
@@ -524,11 +524,16 @@ static void print_json_data(struct libscols_table *tb,
 		ul_jsonwrt_value_raw(&tb->json, name, data);
 		break;
 	case SCOLS_JSON_BOOLEAN:
-		/* name: true|false */
-		ul_jsonwrt_value_boolean(&tb->json, name,
-			!*data ? 0 :
-			*data == '0' ? 0 :
-			*data == 'N' || *data == 'n' ? 0 : 1);
+	case SCOLS_JSON_BOOLEAN_OPTIONAL:
+		/* name: true|false|null */
+		if (cl->json_type == SCOLS_JSON_BOOLEAN_OPTIONAL && (!*data || !strcmp(data, "-"))) {
+			ul_jsonwrt_value_null(&tb->json, name);
+		} else {
+			ul_jsonwrt_value_boolean(&tb->json, name,
+					!*data ? 0 :
+					*data == '0' ? 0 :
+					*data == 'N' || *data == 'n' ? 0 : 1);
+		}
 		break;
 	case SCOLS_JSON_ARRAY_STRING:
 	case SCOLS_JSON_ARRAY_NUMBER: