deferred: make DeferredUpdates::attemptUpdate() use callback owners for $fnameTrxOwner

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

diff --git a/includes/libs/objectcache/WANObjectCache.php b/includes/libs/objectcache/WANObjectCache.php
index 2a8da89..1852685 100644 (file)
--- a/includes/libs/objectcache/WANObjectCache.php
+++ b/includes/libs/objectcache/WANObjectCache.php
@@ -1182,10 +1182,11 @@ class WANObjectCache implements IExpiringStore, IStoreKeyEncoder, LoggerAwareInt
         *      being no stale value available until after a thread completes the callback.
         *      Use WANObjectCache::TSE_NONE to disable this logic.
         *      Default: WANObjectCache::TSE_NONE.
-        *   - busyValue: If no value exists and another thread is currently regenerating it, use this
-        *      as a fallback value (or a callback to generate such a value). This assures that cache
-        *      stampedes cannot happen if the value falls out of cache. This can be used as insurance
-        *      against cache regeneration becoming very slow for some reason (greater than the TTL).
+        *   - busyValue: Specify a placeholder value to use when no value exists and another thread
+        *      is currently regenerating it. This assures that cache stampedes cannot happen if the
+        *      value falls out of cache. This also mitigates stampedes when value regeneration
+        *      becomes very slow (greater than $ttl/"lowTTL"). If this is a closure, then it will
+        *      be invoked to get the placeholder when needed.
         *      Default: null.
         *   - pcTTL: Process cache the value in this PHP instance for this many seconds. This avoids
         *      network I/O when a key is read several times. This will not cache when the callback
@@ -1301,7 +1302,7 @@ class WANObjectCache implements IExpiringStore, IStoreKeyEncoder, LoggerAwareInt
         * @return array Ordered list of the following:
         *   - Cached or regenerated value
         *   - Cached or regenerated value version number or null if not versioned
-        *   - Timestamp of the cached value or null if there is no value
+        *   - Timestamp of the current cached value at the key or null if there is no value
         * @note Callable type hints are not used to avoid class-autoloading
         */
        private function fetchOrRegenerate( $key, $ttl, $callback, array $opts ) {
@@ -1399,11 +1400,7 @@ class WANObjectCache implements IExpiringStore, IStoreKeyEncoder, LoggerAwareInt
                                $miss = is_infinite( $minAsOf ) ? 'renew' : 'miss';
                                $this->stats->increment( "wanobjectcache.$kClass.$miss.busy" );
 
-                               return [
-                                       is_callable( $busyValue ) ? $busyValue() : $busyValue,
-                                       $version,
-                                       $curInfo['asOf']
-                               ];
+                               return [ $this->resolveBusyValue( $busyValue ), $version, $curInfo['asOf'] ];
                        }
                }
 
@@ -1604,6 +1601,14 @@ class WANObjectCache implements IExpiringStore, IStoreKeyEncoder, LoggerAwareInt
                );
        }
 
+       /**
+        * @param mixed $busyValue
+        * @return mixed
+        */
+       private function resolveBusyValue( $busyValue ) {
+               return ( $busyValue instanceof Closure ) ? $busyValue() : $busyValue;
+       }
+
        /**
         * Method to fetch multiple cache keys at once with regeneration
         *
@@ -1885,22 +1890,22 @@ class WANObjectCache implements IExpiringStore, IStoreKeyEncoder, LoggerAwareInt
        /**
         * @see BagOStuff::makeKey()
         * @param string $class Key class
-        * @param string|null $component [optional] Key component (starting with a key collection name)
-        * @return string Colon-delimited list of $keyspace followed by escaped components of $args
+        * @param string ...$components Key components (starting with a key collection name)
+        * @return string Colon-delimited list of $keyspace followed by escaped components
         * @since 1.27
         */
-       public function makeKey( $class, $component = null ) {
+       public function makeKey( $class, ...$components ) {
                return $this->cache->makeKey( ...func_get_args() );
        }
 
        /**
         * @see BagOStuff::makeGlobalKey()
         * @param string $class Key class
-        * @param string|null $component [optional] Key component (starting with a key collection name)
-        * @return string Colon-delimited list of $keyspace followed by escaped components of $args
+        * @param string ...$components Key components (starting with a key collection name)
+        * @return string Colon-delimited list of $keyspace followed by escaped components
         * @since 1.27
         */
-       public function makeGlobalKey( $class, $component = null ) {
+       public function makeGlobalKey( $class, ...$components ) {
                return $this->cache->makeGlobalKey( ...func_get_args() );
        }