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authorLennart Poettering <lennart@poettering.net>2013-05-16 21:52:35 +0200
committerLennart Poettering <lennart@poettering.net>2013-05-16 21:58:34 +0200
commite4ee6e5cc3e8e23e1ecc0d9fa756d9cc2534d218 (patch)
tree4264b1334f465b36c7f8c726eb9bf94f00ac5550 /src/shared/refcnt.h
parenteb01ba5de14859d7a94835ab9299de40132d549a (diff)
bus: make bus ref counting atomic
This is preparation to allow sd_bus_message obejcts to be processed in a different thread from their originating sd_bus object.
Diffstat (limited to 'src/shared/refcnt.h')
-rw-r--r--src/shared/refcnt.h34
1 files changed, 34 insertions, 0 deletions
diff --git a/src/shared/refcnt.h b/src/shared/refcnt.h
new file mode 100644
index 0000000000..0502c20a2e
--- /dev/null
+++ b/src/shared/refcnt.h
@@ -0,0 +1,34 @@
+/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
+
+#pragma once
+
+/***
+ This file is part of systemd.
+
+ Copyright 2013 Lennart Poettering
+
+ systemd is free software; you can redistribute it and/or modify it
+ under the terms of the GNU Lesser General Public License as published by
+ the Free Software Foundation; either version 2.1 of the License, or
+ (at your option) any later version.
+
+ systemd is distributed in the hope that it will be useful, but
+ WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public License
+ along with systemd; If not, see <http://www.gnu.org/licenses/>.
+***/
+
+/* A type-safe atomic refcounter */
+
+typedef struct {
+ volatile unsigned _value;
+} RefCount;
+
+#define REFCNT_GET(r) ((r)._value)
+#define REFCNT_INC(r) (__sync_add_and_fetch(&(r)._value, 1))
+#define REFCNT_DEC(r) (__sync_sub_and_fetch(&(r)._value, 1))
+
+#define REFCNT_INIT ((RefCount) { ._value = 1 })