Attachment 49675 Details for Bug 38005 – Implement _dbus_atomic_get directly, rather than via inc + dec (v2)

[patch] Implement _dbus_atomic_get directly, rather than via inc + dec (v2)

0001-Implement-_dbus_atomic_get-directly-rather-than-via-.patch (text/plain), 3.27 KB, created by Simon McVittie on 2011-07-28 09:17:45 UTC

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Creator: Simon McVittie

Created: 2011-07-28 09:17:45 UTC

Size: 3.27 KB

patch

obsolete

>From 74ed92b108f5136107ba4bb8d80f460abd3164a7 Mon Sep 17 00:00:00 2001
>From: Simon McVittie <simon.mcvittie@collabora.co.uk>
>Date: Thu, 28 Jul 2011 16:58:05 +0100
>Subject: [PATCH] Implement _dbus_atomic_get directly, rather than via inc +
> dec
>
>The Windows implementation is untested, but does at least (cross-)compile,
>and matches what GLib does.
>
>Bug: https://bugs.freedesktop.org/show_bug.cgi?id=38005
>---
> dbus/dbus-sysdeps-unix.c |   23 +++++++++++++++++++++++
> dbus/dbus-sysdeps-win.c  |   15 +++++++++++++++
> dbus/dbus-sysdeps.c      |   24 ------------------------
> 3 files changed, 38 insertions(+), 24 deletions(-)
>
>diff --git a/dbus/dbus-sysdeps-unix.c b/dbus/dbus-sysdeps-unix.c
>index d606371..bc40e45 100644
>--- a/dbus/dbus-sysdeps-unix.c
>+++ b/dbus/dbus-sysdeps-unix.c
>@@ -2359,6 +2359,29 @@ _dbus_atomic_dec (DBusAtomic *atomic)
> #endif
> }
> 
>+/**
>+ * Atomically get the value of an integer. It may change at any time
>+ * thereafter, so this is mostly only useful for assertions.
>+ *
>+ * @param atomic pointer to the integer to get
>+ * @returns the value at this moment
>+ */
>+dbus_int32_t
>+_dbus_atomic_get (DBusAtomic *atomic)
>+{
>+#if DBUS_USE_SYNC
>+  __sync_synchronize ();
>+  return atomic->value;
>+#else
>+  dbus_int32_t res;
>+
>+  _DBUS_LOCK (atomic);
>+  res = atomic->value;
>+  _DBUS_UNLOCK (atomic);
>+  return res;
>+#endif
>+}
>+
> #ifdef DBUS_BUILD_TESTS
> /** Gets our GID
>  * @returns process GID
>diff --git a/dbus/dbus-sysdeps-win.c b/dbus/dbus-sysdeps-win.c
>index f9afada..a8c60bd 100644
>--- a/dbus/dbus-sysdeps-win.c
>+++ b/dbus/dbus-sysdeps-win.c
>@@ -3082,6 +3082,21 @@ _dbus_atomic_dec (DBusAtomic *atomic)
> }
> 
> /**
>+ * Atomically get the value of an integer. It may change at any time
>+ * thereafter, so this is mostly only useful for assertions.
>+ *
>+ * @param atomic pointer to the integer to get
>+ * @returns the value at this moment
>+ */
>+dbus_int32_t
>+_dbus_atomic_get (DBusAtomic *atomic)
>+{
>+  /* this is what GLib does, hopefully it's right... */
>+  MemoryBarrier ();
>+  return atomic->value;
>+}
>+
>+/**
>  * Called when the bus daemon is signaled to reload its configuration; any
>  * caches should be nuked. Of course any caches that need explicit reload
>  * are probably broken, but c'est la vie.
>diff --git a/dbus/dbus-sysdeps.c b/dbus/dbus-sysdeps.c
>index 18f69dc..bab516d 100644
>--- a/dbus/dbus-sysdeps.c
>+++ b/dbus/dbus-sysdeps.c
>@@ -1067,30 +1067,6 @@ _dbus_strerror_from_errno (void)
>   return _dbus_strerror (errno);
> }
> 
>-/**
>- * Atomically get the value of an integer. It may change at any time
>- * thereafter, so this is mostly only useful for assertions.
>- *
>- * This function temporarily increases the atomic integer, so only
>- * use it in contexts where that would be OK (such as refcounts).
>- *
>- * @param atomic pointer to the integer to increment
>- * @returns the value at this moment
>- */
>-dbus_int32_t
>-_dbus_atomic_get (DBusAtomic *atomic)
>-{
>-  dbus_int32_t old_value;
>-
>-  /* On Windows we use InterlockedIncrement and InterlockedDecrement,
>-   * and there is no InterlockedGet, so we have to change the value.
>-   * Increasing it is less likely to have bad side-effects (for instance,
>-   * it's OK for refcounts). */
>-  old_value = _dbus_atomic_inc (atomic);
>-  _dbus_atomic_dec (atomic);
>-  return old_value;
>-}
>-
> /** @} end of sysdeps */
> 
> /* tests in dbus-sysdeps-util.c */
>-- 
>1.7.5.4
>

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Attachments on bug 38005: 47660 | 48335 | 48336 | 48337 | 48338 | 48339 | 48340 | 48341 | 48342 | 49096 | 49097 | 49098 | 49100 | 49102 | 49103 | 49349 | 49675

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