From ac9f998abdceb21fbbda4e8dee0e8b16c2f5ec4e Mon Sep 17 00:00:00 2001
From: Robin Appelman <icewind@owncloud.com>
Date: Mon, 8 Jun 2015 15:25:23 +0200
Subject: [PATCH] add compare-and-delete to the memcache interface
---
lib/private/memcache/apc.php | 2 ++
lib/private/memcache/arraycache.php | 2 ++
lib/private/memcache/cadtrait.php | 53 +++++++++++++++++++++++++++++
lib/private/memcache/memcached.php | 2 ++
lib/private/memcache/nullcache.php | 4 +++
lib/private/memcache/xcache.php | 2 ++
lib/public/imemcache.php | 10 ++++++
tests/lib/memcache/cache.php | 12 +++++++
8 files changed, 87 insertions(+)
create mode 100644 lib/private/memcache/cadtrait.php
diff --git a/lib/private/memcache/apc.php b/lib/private/memcache/apc.php
index 50b942e7297..f768cdc1c6e 100644
--- a/lib/private/memcache/apc.php
+++ b/lib/private/memcache/apc.php
@@ -31,6 +31,8 @@ class APC extends Cache implements IMemcache {
cas as casEmulated;
}
+ use CADTrait;
+
public function get($key) {
$result = apc_fetch($this->getPrefix() . $key, $success);
if (!$success) {
diff --git a/lib/private/memcache/arraycache.php b/lib/private/memcache/arraycache.php
index 2b1b87a9eb3..8a3fdd2f7c5 100644
--- a/lib/private/memcache/arraycache.php
+++ b/lib/private/memcache/arraycache.php
@@ -28,6 +28,8 @@ class ArrayCache extends Cache implements IMemcache {
/** @var array Array with the cached data */
protected $cachedData = array();
+ use CADTrait;
+
/**
* {@inheritDoc}
*/
diff --git a/lib/private/memcache/cadtrait.php b/lib/private/memcache/cadtrait.php
new file mode 100644
index 00000000000..e9836e24040
--- /dev/null
+++ b/lib/private/memcache/cadtrait.php
@@ -0,0 +1,53 @@
+<?php
+/**
+ * @author Robin Appelman <icewind@owncloud.com>
+ *
+ * @copyright Copyright (c) 2015, ownCloud, Inc.
+ * @license AGPL-3.0
+ *
+ * This code is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License, version 3,
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License, version 3,
+ * along with this program. If not, see <http://www.gnu.org/licenses/>
+ *
+ */
+
+namespace OC\Memcache;
+
+trait CADTrait {
+ abstract public function get($key);
+
+ abstract public function remove($key);
+
+ abstract public function add($key, $value, $ttl = 0);
+
+ /**
+ * Compare and delete
+ *
+ * @param string $key
+ * @param mixed $old
+ * @return bool
+ */
+ public function cad($key, $old) {
+ //no native cas, emulate with locking
+ if ($this->add($key . '_lock', true)) {
+ if ($this->get($key) === $old) {
+ $this->remove($key);
+ $this->remove($key . '_lock');
+ return true;
+ } else {
+ $this->remove($key . '_lock');
+ return false;
+ }
+ } else {
+ return false;
+ }
+ }
+}
diff --git a/lib/private/memcache/memcached.php b/lib/private/memcache/memcached.php
index cf1d651b551..1503851fd73 100644
--- a/lib/private/memcache/memcached.php
+++ b/lib/private/memcache/memcached.php
@@ -34,6 +34,8 @@ class Memcached extends Cache implements IMemcache {
*/
private static $cache = null;
+ use CADTrait;
+
public function __construct($prefix = '') {
parent::__construct($prefix);
if (is_null(self::$cache)) {
diff --git a/lib/private/memcache/nullcache.php b/lib/private/memcache/nullcache.php
index 77eadba4eba..f971ffc9b2d 100644
--- a/lib/private/memcache/nullcache.php
+++ b/lib/private/memcache/nullcache.php
@@ -55,6 +55,10 @@ class NullCache extends Cache implements \OCP\IMemcache {
return true;
}
+ public function cad($key, $old) {
+ return true;
+ }
+
public function clear($prefix = '') {
return true;
}
diff --git a/lib/private/memcache/xcache.php b/lib/private/memcache/xcache.php
index 0be79d06ed9..a6265ed5622 100644
--- a/lib/private/memcache/xcache.php
+++ b/lib/private/memcache/xcache.php
@@ -34,6 +34,8 @@ use OCP\IMemcache;
class XCache extends Cache implements IMemcache {
use CASTrait;
+ use CADTrait;
+
/**
* entries in XCache gets namespaced to prevent collisions between ownCloud instances and users
*/
diff --git a/lib/public/imemcache.php b/lib/public/imemcache.php
index f8b898e54c6..a1a00791b63 100644
--- a/lib/public/imemcache.php
+++ b/lib/public/imemcache.php
@@ -76,4 +76,14 @@ interface IMemcache extends ICache {
* @since 8.1.0
*/
public function cas($key, $old, $new);
+
+ /**
+ * Compare and delete
+ *
+ * @param string $key
+ * @param mixed $old
+ * @return bool
+ * @since 8.1.0
+ */
+ public function cad($key, $old);
}
diff --git a/tests/lib/memcache/cache.php b/tests/lib/memcache/cache.php
index 9d977cf0247..3ff72ee931c 100644
--- a/tests/lib/memcache/cache.php
+++ b/tests/lib/memcache/cache.php
@@ -103,6 +103,18 @@ abstract class Cache extends \Test_Cache {
$this->assertEquals('bar1', $this->instance->get('foo'));
}
+ public function testCadNotChanged() {
+ $this->instance->set('foo', 'bar');
+ $this->assertTrue($this->instance->cad('foo', 'bar'));
+ $this->assertFalse($this->instance->hasKey('foo'));
+ }
+
+ public function testCadChanged() {
+ $this->instance->set('foo', 'bar1');
+ $this->assertFalse($this->instance->cad('foo', 'bar'));
+ $this->assertTrue($this->instance->hasKey('foo'));
+ }
+
protected function tearDown() {
if ($this->instance) {
--
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