collation: Refactor getFirstLetterData() cache handling

* Factor out fetchFirstLetterData() as a separate method.
* Move 'version' into the key instead of checking afterwards.
* Use getWithSetCallback() for the cache handling.
  (Depends on version being in the key).

Change-Id: I15bddf5d1dabcdcef47a938447ba59436bd8a294

diff --git a/includes/collation/IcuCollation.php b/includes/collation/IcuCollation.php
index 942036b..a374b13 100644 (file)
--- a/includes/collation/IcuCollation.php
+++ b/includes/collation/IcuCollation.php
@@ -234,32 +234,33 @@ class IcuCollation extends Collation {
 
        /**
         * @since 1.16.3
+        * @return array
         */
        public function getFirstLetterData() {
-               if ( $this->firstLetterData !== null ) {
-                       return $this->firstLetterData;
-               }
-
-               $cache = ObjectCache::getLocalServerInstance( CACHE_ANYTHING );
-               $cacheKey = $cache->makeKey(
-                       'first-letters',
-                       $this->locale,
-                       $this->digitTransformLanguage->getCode(),
-                       self::getICUVersion()
-               );
-               $cacheEntry = $cache->get( $cacheKey );
-
-               if ( $cacheEntry && isset( $cacheEntry['version'] )
-                       && $cacheEntry['version'] == self::FIRST_LETTER_VERSION
-               ) {
-                       $this->firstLetterData = $cacheEntry;
-                       return $this->firstLetterData;
+               if ( $this->firstLetterData === null ) {
+                       $cache = ObjectCache::getLocalServerInstance( CACHE_ANYTHING );
+                       $cacheKey = $cache->makeKey(
+                               'first-letters',
+                               $this->locale,
+                               $this->digitTransformLanguage->getCode(),
+                               self::getICUVersion(),
+                               self::FIRST_LETTER_VERSION
+                       );
+                       $this->firstLetterData = $cache->getWithSetCallback( $cacheKey, $cache::TTL_WEEK, function () {
+                               return $this->fetchFirstLetterData();
+                       } );
                }
+               return $this->firstLetterData;
+       }
 
+       /**
+        * @return array
+        * @throws MWException
+        */
+       private function fetchFirstLetterData() {
                // Generate data from serialized data file
-
                if ( isset( self::$tailoringFirstLetters[$this->locale] ) ) {
-                       $letters = wfGetPrecompiledData( "first-letters-root.ser" );
+                       $letters = wfGetPrecompiledData( 'first-letters-root.ser' );
                        // Append additional characters
                        $letters = array_merge( $letters, self::$tailoringFirstLetters[$this->locale] );
                        // Remove unnecessary ones, if any
@@ -374,15 +375,11 @@ class IcuCollation extends Collation {
                $data = [
                        'chars' => array_values( $letterMap ),
                        'keys' => array_keys( $letterMap ),
-                       'version' => self::FIRST_LETTER_VERSION,
                ];
 
                // Reduce memory usage before caching
                unset( $letterMap );
 
-               // Save to cache
-               $this->firstLetterData = $data;
-               $cache->set( $cacheKey, $data, $cache::TTL_WEEK );
                return $data;
        }
 
@@ -390,30 +387,21 @@ class IcuCollation extends Collation {
         * @since 1.16.3
         */
        public function getLetterByIndex( $index ) {
-               if ( $this->firstLetterData === null ) {
-                       $this->getFirstLetterData();
-               }
-               return $this->firstLetterData['chars'][$index];
+               return $this->getFirstLetterData()['chars'][$index];
        }
 
        /**
         * @since 1.16.3
         */
        public function getSortKeyByLetterIndex( $index ) {
-               if ( $this->firstLetterData === null ) {
-                       $this->getFirstLetterData();
-               }
-               return $this->firstLetterData['keys'][$index];
+               return $this->getFirstLetterData()['keys'][$index];
        }
 
        /**
         * @since 1.16.3
         */
        public function getFirstLetterCount() {
-               if ( $this->firstLetterData === null ) {
-                       $this->getFirstLetterData();
-               }
-               return count( $this->firstLetterData['chars'] );
+               return count( $this->getFirstLetterData()['chars'] );
        }
 
        /**