objectcache: restore a simple version of the apc.serializer check in APCUBagOStuff

[lhc/web/wiklou.git] / includes / libs / objectcache / APCUBagOStuff.php

diff --git a/includes/libs/objectcache/APCUBagOStuff.php b/includes/libs/objectcache/APCUBagOStuff.php
index da6544b..eba0af5 100644 (file)
--- a/includes/libs/objectcache/APCUBagOStuff.php
+++ b/includes/libs/objectcache/APCUBagOStuff.php
@@ -24,19 +24,30 @@
 /**
  * This is a wrapper for APCU's shared memory functions
  *
+ * Use PHP serialization to avoid bugs and easily create CAS tokens.
+ * APCu has a memory corruption bug when the serializer is set to 'default'.
+ * See T120267, and upstream bug reports:
+ *  - https://github.com/krakjoe/apcu/issues/38
+ *  - https://github.com/krakjoe/apcu/issues/35
+ *  - https://github.com/krakjoe/apcu/issues/111
+ *
  * @ingroup Cache
  */
-class APCUBagOStuff extends APCBagOStuff {
+class APCUBagOStuff extends BagOStuff {
+       /** @var bool Whether to trust the APC implementation to serialization */
+       private $nativeSerialize;
+
        /**
-        * Available parameters are:
-        *   - nativeSerialize:     If true, pass objects to apcu_store(), and trust it
-        *                          to serialize them correctly. If false, serialize
-        *                          all values in PHP.
-        *
-        * @param array $params
+        * @var string String to append to each APC key. This may be changed
+        *  whenever the handling of values is changed, to prevent existing code
+        *  from encountering older values which it cannot handle.
         */
+       const KEY_SUFFIX = ':4';
+
        public function __construct( array $params = [] ) {
                parent::__construct( $params );
+               // The extension serialize is still buggy, unlike "php" and "igbinary"
+               $this->nativeSerialize = ( ini_get( 'apc.serializer' ) !== 'default' );
        }
 
        protected function doGet( $key, $flags = 0, &$casToken = null ) {
@@ -52,13 +63,11 @@ class APCUBagOStuff extends APCBagOStuff {
        }
 
        public function set( $key, $value, $exptime = 0, $flags = 0 ) {
-               apcu_store(
+               return apcu_store(
                        $key . self::KEY_SUFFIX,
                        $this->serialize( $value ),
                        $exptime
                );
-
-               return true;
        }
 
        public function add( $key, $value, $exptime = 0, $flags = 0 ) {
@@ -76,11 +85,7 @@ class APCUBagOStuff extends APCBagOStuff {
        }
 
        public function incr( $key, $value = 1 ) {
-               /**
-                * @todo When we only support php 7 or higher remove this hack
-                *
-                * https://github.com/krakjoe/apcu/issues/166
-                */
+               // https://github.com/krakjoe/apcu/issues/166
                if ( apcu_exists( $key . self::KEY_SUFFIX ) ) {
                        return apcu_inc( $key . self::KEY_SUFFIX, $value );
                } else {
@@ -89,15 +94,27 @@ class APCUBagOStuff extends APCBagOStuff {
        }
 
        public function decr( $key, $value = 1 ) {
-               /**
-                * @todo When we only support php 7 or higher remove this hack
-                *
-                * https://github.com/krakjoe/apcu/issues/166
-                */
+               // https://github.com/krakjoe/apcu/issues/166
                if ( apcu_exists( $key . self::KEY_SUFFIX ) ) {
                        return apcu_dec( $key . self::KEY_SUFFIX, $value );
                } else {
                        return false;
                }
        }
+
+       protected function serialize( $value ) {
+               if ( $this->nativeSerialize ) {
+                       return $value;
+               }
+
+               return $this->isInteger( $value ) ? (int)$value : serialize( $value );
+       }
+
+       protected function unserialize( $value ) {
+               if ( $this->nativeSerialize ) {
+                       return $value;
+               }
+
+               return $this->isInteger( $value ) ? (int)$value : unserialize( $value );
+       }
 }