From afd15bbb4b6414b9356799c63029e36642dae8e4 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Zbigniew=20J=C4=99drzejewski-Szmek?= <zbyszek@in.waw.pl>
Date: Wed, 8 May 2019 14:39:57 +0200
Subject: [PATCH] sd-event: add sd_event_source_disable_unref() helper

---
 man/rules/meson.build              |  4 +++-
 man/sd_event_source_unref.xml      | 30 +++++++++++++++++++-----------
 src/libsystemd/libsystemd.sym      |  1 +
 src/libsystemd/sd-event/sd-event.c |  6 ++++++
 src/systemd/sd-event.h             |  1 +
 5 files changed, 30 insertions(+), 12 deletions(-)

diff --git a/man/rules/meson.build b/man/rules/meson.build
index 6894158466..944d2bf286 100644
--- a/man/rules/meson.build
+++ b/man/rules/meson.build
@@ -445,7 +445,9 @@ manpages = [
  ['sd_event_source_set_userdata', '3', ['sd_event_source_get_userdata'], ''],
  ['sd_event_source_unref',
   '3',
-  ['sd_event_source_ref', 'sd_event_source_unrefp'],
+  ['sd_event_source_disable_unref',
+   'sd_event_source_ref',
+   'sd_event_source_unrefp'],
   ''],
  ['sd_event_wait',
   '3',
diff --git a/man/sd_event_source_unref.xml b/man/sd_event_source_unref.xml
index 01e3008eed..4e2fb8cb39 100644
--- a/man/sd_event_source_unref.xml
+++ b/man/sd_event_source_unref.xml
@@ -19,6 +19,7 @@
     <refname>sd_event_source_unref</refname>
     <refname>sd_event_source_unrefp</refname>
     <refname>sd_event_source_ref</refname>
+    <refname>sd_event_source_disable_unref</refname>
 
     <refpurpose>Increase or decrease event source reference counters</refpurpose>
   </refnamediv>
@@ -42,6 +43,10 @@
         <paramdef>sd_event_source *<parameter>source</parameter></paramdef>
       </funcprototype>
 
+      <funcprototype>
+        <funcdef>sd_event_source* <function>sd_event_source_disable_unref</function></funcdef>
+        <paramdef>sd_event_source *<parameter>source</parameter></paramdef>
+      </funcprototype>
     </funcsynopsis>
   </refsynopsisdiv>
 
@@ -77,23 +82,26 @@
     the passed event source object is
     <constant>NULL</constant>.</para>
 
-    <para>Note that event source objects stay alive and may be
-    dispatched as long as they have a reference counter greater than
-    zero. In order to drop a reference of an event source and make
-    sure the associated event source handler function is not called
-    anymore it is recommended to combine a call of
+    <para>Note that event source objects stay alive and may be dispatched as long as they have a reference
+    counter greater than zero. In order to drop a reference of an event source and make sure the associated
+    event source handler function is not called anymore it is recommended to combine a call of
     <function>sd_event_source_unref()</function> with a prior call to
-    <function>sd_event_source_set_enabled()</function> with
-    <constant>SD_EVENT_OFF</constant>.</para>
+    <function>sd_event_source_set_enabled()</function> with <constant>SD_EVENT_OFF</constant> or call
+    <function>sd_event_source_disable_unref()</function>, see below.</para>
+
+    <para><function>sd_event_source_disable_unref()</function> combines a call to
+    <function>sd_event_source_set_enabled()</function> with <constant>SD_EVENT_OFF</constant> with
+    <function>sd_event_source_unref()</function>. This ensures that the source is disabled before the local
+    reference to it is lost. The <parameter>source</parameter> parameter is allowed to be
+    <constant>NULL</constant>.</para>
   </refsect1>
 
   <refsect1>
     <title>Return Value</title>
 
-    <para><function>sd_event_source_unref()</function> always returns
-    <constant>NULL</constant>.
-    <function>sd_event_source_ref()</function> always returns the
-    event source object passed in.</para>
+    <para><function>sd_event_source_unref()</function> and
+    <function>sd_event_source_disable_unref()</function> always return <constant>NULL</constant>.
+    <function>sd_event_source_ref()</function> always returns the event source object passed in.</para>
   </refsect1>
 
   <xi:include href="libsystemd-pkgconfig.xml" />
diff --git a/src/libsystemd/libsystemd.sym b/src/libsystemd/libsystemd.sym
index a9ab0605ce..5ec42e0f1f 100644
--- a/src/libsystemd/libsystemd.sym
+++ b/src/libsystemd/libsystemd.sym
@@ -680,4 +680,5 @@ global:
 LIBSYSTEMD_243 {
 global:
         sd_bus_object_vtable_format;
+        sd_event_source_disable_unref;
 } LIBSYSTEMD_241;
diff --git a/src/libsystemd/sd-event/sd-event.c b/src/libsystemd/sd-event/sd-event.c
index 50017a9517..09285c19d8 100644
--- a/src/libsystemd/sd-event/sd-event.c
+++ b/src/libsystemd/sd-event/sd-event.c
@@ -339,6 +339,12 @@ fail:
 
 DEFINE_PUBLIC_TRIVIAL_REF_UNREF_FUNC(sd_event, sd_event, event_free);
 
+_public_ sd_event_source* sd_event_source_disable_unref(sd_event_source *s) {
+        if (s)
+                (void) sd_event_source_set_enabled(s, SD_EVENT_OFF);
+        return sd_event_source_unref(s);
+}
+
 static bool event_pid_changed(sd_event *e) {
         assert(e);
 
diff --git a/src/systemd/sd-event.h b/src/systemd/sd-event.h
index 7bb8609376..226e1b8f26 100644
--- a/src/systemd/sd-event.h
+++ b/src/systemd/sd-event.h
@@ -113,6 +113,7 @@ int sd_event_get_iteration(sd_event *e, uint64_t *ret);
 
 sd_event_source* sd_event_source_ref(sd_event_source *s);
 sd_event_source* sd_event_source_unref(sd_event_source *s);
+sd_event_source* sd_event_source_disable_unref(sd_event_source *s);
 
 sd_event *sd_event_source_get_event(sd_event_source *s);
 void* sd_event_source_get_userdata(sd_event_source *s);