Merge "Swap german alias order for img_thumbnail and img_manualthumb"

[lhc/web/wiklou.git] / includes / libs / MapCacheLRU.php

diff --git a/includes/libs/MapCacheLRU.php b/includes/libs/MapCacheLRU.php
index c92769f..553315f 100644 (file)
--- a/includes/libs/MapCacheLRU.php
+++ b/includes/libs/MapCacheLRU.php
@@ -48,16 +48,45 @@ class MapCacheLRU {
                $this->maxCacheKeys = $maxKeys;
        }
 
+       /**
+        * @param array $values Key/value map in order of increasingly recent access
+        * @param int $maxKeys
+        * @return MapCacheLRU
+        * @since 1.30
+        */
+       public static function newFromArray( array $values, $maxKeys ) {
+               $mapCache = new self( $maxKeys );
+               $mapCache->cache = ( count( $values ) > $maxKeys )
+                       ? array_slice( $values, -$maxKeys, null, true )
+                       : $values;
+
+               return $mapCache;
+       }
+
+       /**
+        * @return array Key/value map in order of increasingly recent access
+        * @since 1.30
+        */
+       public function toArray() {
+               return $this->cache;
+       }
+
        /**
         * Set a key/value pair.
         * This will prune the cache if it gets too large based on LRU.
         * If the item is already set, it will be pushed to the top of the cache.
         *
+        * To reduce evictions due to one-off use of many new keys, $rank can be
+        * set to have keys start at the top of a bottom fraction of the list. A value
+        * of 3/8 means values start at the top of the bottom 3/8s of the list and are
+        * moved to the top of the list when accessed a second time.
+        *
         * @param string $key
         * @param mixed $value
+        * @param float $rank Bottom fraction of the list where keys start off [Default: 1.0]
         * @return void
         */
-       public function set( $key, $value ) {
+       public function set( $key, $value, $rank = 1.0 ) {
                if ( $this->has( $key ) ) {
                        $this->ping( $key );
                } elseif ( count( $this->cache ) >= $this->maxCacheKeys ) {
@@ -65,7 +94,15 @@ class MapCacheLRU {
                        $evictKey = key( $this->cache );
                        unset( $this->cache[$evictKey] );
                }
-               $this->cache[$key] = $value;
+
+               if ( $rank < 1.0 && $rank > 0 ) {
+                       $offset = intval( $rank * count( $this->cache ) );
+                       $this->cache = array_slice( $this->cache, 0, $offset, true )
+                               + [ $key => $value ]
+                               + array_slice( $this->cache, $offset, null, true );
+               } else {
+                       $this->cache[$key] = $value;
+               }
        }
 
        /**
@@ -116,15 +153,16 @@ class MapCacheLRU {
         * @since 1.28
         * @param string $key
         * @param callable $callback Callback that will produce the value
+        * @param float $rank Bottom fraction of the list where keys start off [Default: 1.0]
         * @return mixed The cached value if found or the result of $callback otherwise
         */
-       public function getWithSetCallback( $key, callable $callback ) {
+       public function getWithSetCallback( $key, callable $callback, $rank = 1.0 ) {
                if ( $this->has( $key ) ) {
                        $value = $this->get( $key );
                } else {
                        $value = call_user_func( $callback );
                        if ( $value !== false ) {
-                               $this->set( $key, $value );
+                               $this->set( $key, $value, $rank );
                        }
                }