From: Lennart Poettering <lennart@poettering.net>
Date: Wed, 29 May 2019 10:24:40 +0000 (+0200)
Subject: json: add new flag for forcing a flush after dumping json data to file
X-Git-Tag: v245-rc1~249^2~6
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=0b1f2e8a061721b37100380bd3c9ee4b97cb35cf;p=thirdparty%2Fsystemd.git

json: add new flag for forcing a flush after dumping json data to file

This is particularly useful when no trailing \n is generated, i.e. stdio
doesn't flush the output on its own.
---

diff --git a/src/shared/json.c b/src/shared/json.c
index 38b2bb14e4d..7abbd1917d8 100644
--- a/src/shared/json.c
+++ b/src/shared/json.c
@@ -1767,6 +1767,9 @@ void json_variant_dump(JsonVariant *v, JsonFormatFlags flags, FILE *f, const cha
                 fputc('\n', f);
         if (flags & JSON_FORMAT_SSE)
                 fputc('\n', f); /* In case of SSE add a second newline */
+
+        if (flags & JSON_FORMAT_FLUSH)
+                fflush(f);
 }
 
 int json_variant_filter(JsonVariant **v, char **to_remove) {
diff --git a/src/shared/json.h b/src/shared/json.h
index 40e74e03a48..749c25253f8 100644
--- a/src/shared/json.h
+++ b/src/shared/json.h
@@ -168,6 +168,7 @@ typedef enum JsonFormatFlags {
         JSON_FORMAT_SOURCE     = 1 << 4, /* prefix with source filename/line/column */
         JSON_FORMAT_SSE        = 1 << 5, /* prefix/suffix with W3C server-sent events */
         JSON_FORMAT_SEQ        = 1 << 6, /* prefix/suffix with RFC 7464 application/json-seq */
+        JSON_FORMAT_FLUSH      = 1 << 7, /* call fflush() after dumping JSON */
 } JsonFormatFlags;
 
 int json_variant_format(JsonVariant *v, JsonFormatFlags flags, char **ret);