json: Add utility to add a null-member

Signed-off-by: Christian Decker <decker.christian@gmail.com>

lightningd/json.c

@@ -299,6 +299,11 @@ void json_add_bool(struct json_stream *result, const char *fieldname, bool value
 	json_add_member(result, fieldname, value ? "true" : "false");
 }
 
+void json_add_null(struct json_stream *stream, const char *fieldname)
+{
+	json_add_member(stream, fieldname, "null");
+}
+
 void json_add_hex(struct json_stream *result, const char *fieldname,
 		  const void *data, size_t len)
 {

lightningd/json.h

@@ -115,6 +115,10 @@ void json_add_u64(struct json_stream *result, const char *fieldname,
 /* '"fieldname" : true|false' or 'true|false' if fieldname is NULL */
 void json_add_bool(struct json_stream *result, const char *fieldname,
 		   bool value);
+
+/* '"fieldname" : null' or 'null' if fieldname is NULL */
+void json_add_null(struct json_stream *stream, const char *fieldname);
+
 /* '"fieldname" : "0189abcdef..."' or "0189abcdef..." if fieldname is NULL */
 void json_add_hex(struct json_stream *result, const char *fieldname,
 		  const void *data, size_t len);

lightningd/test/run-invoice-select-inchan.c

@@ -142,6 +142,9 @@ void json_add_hex_talarr(struct json_stream *result UNNEEDED,
 void json_add_log(struct json_stream *result UNNEEDED,
 		  const struct log_book *lr UNNEEDED, enum log_level minlevel UNNEEDED)
 { fprintf(stderr, "json_add_log called!\n"); abort(); }
+/* Generated stub for json_add_null */
+void json_add_null(struct json_stream *stream UNNEEDED, const char *fieldname UNNEEDED)
+{ fprintf(stderr, "json_add_null called!\n"); abort(); }
 /* Generated stub for json_add_num */
 void json_add_num(struct json_stream *result UNNEEDED, const char *fieldname UNNEEDED,
 		  unsigned int value UNNEEDED)

wallet/test/run-wallet.c

@@ -215,6 +215,9 @@ void json_add_hex_talarr(struct json_stream *result UNNEEDED,
 void json_add_log(struct json_stream *result UNNEEDED,
 		  const struct log_book *lr UNNEEDED, enum log_level minlevel UNNEEDED)
 { fprintf(stderr, "json_add_log called!\n"); abort(); }
+/* Generated stub for json_add_null */
+void json_add_null(struct json_stream *stream UNNEEDED, const char *fieldname UNNEEDED)
+{ fprintf(stderr, "json_add_null called!\n"); abort(); }
 /* Generated stub for json_add_num */
 void json_add_num(struct json_stream *result UNNEEDED, const char *fieldname UNNEEDED,
 		  unsigned int value UNNEEDED)