objectcache: add "staleTTL" option to WANObjectCache::set()

Change-Id: Ib9386a8ad4ab98d07d0a3784e3afffeeca9bbd6e

diff --git a/includes/libs/objectcache/WANObjectCache.php b/includes/libs/objectcache/WANObjectCache.php
index adb2899..126a5ed 100644 (file)
--- a/includes/libs/objectcache/WANObjectCache.php
+++ b/includes/libs/objectcache/WANObjectCache.php
@@ -404,6 +404,12 @@ class WANObjectCache implements IExpiringStore, LoggerAwareInterface {
         *      with this TTL and flag it as stale. This is only useful if the reads for
         *      this key use getWithSetCallback() with "lockTSE" set.
         *      Default: WANObjectCache::TSE_NONE
+        *   - staleTTL : Seconds to keep the key around if it is stale. The get()/getMulti()
+        *      methods return such stale values with a $curTTL of 0, and getWithSetCallback()
+        *      will call the regeneration callback in such cases, passing in the old value
+        *      and its as-of time to the callback. This is useful if adaptiveTTL() is used
+        *      on the old value's as-of time when it is verified as still being correct.
+        *      Default: 0.
         * @return bool Success
         */
        final public function set( $key, $value, $ttl = 0, array $opts = [] ) {
@@ -411,6 +417,7 @@ class WANObjectCache implements IExpiringStore, LoggerAwareInterface {
                $lockTSE = isset( $opts['lockTSE'] ) ? $opts['lockTSE'] : self::TSE_NONE;
                $age = isset( $opts['since'] ) ? max( 0, $now - $opts['since'] ) : 0;
                $lag = isset( $opts['lag'] ) ? $opts['lag'] : 0;
+               $staleTTL = isset( $opts['staleTTL'] ) ? $opts['staleTTL'] : 0;
 
                // Do not cache potentially uncommitted data as it might get rolled back
                if ( !empty( $opts['pending'] ) ) {
@@ -452,7 +459,7 @@ class WANObjectCache implements IExpiringStore, LoggerAwareInterface {
                                : $wrapped;
                };
 
-               return $this->cache->merge( self::VALUE_KEY_PREFIX . $key, $func, $ttl, 1 );
+               return $this->cache->merge( self::VALUE_KEY_PREFIX . $key, $func, $ttl + $staleTTL, 1 );
        }
 
        /**