1 files changed, 245 insertions, 0 deletions
diff --git a/www/wiki/includes/cache/MessageBlobStore.php b/www/wiki/includes/cache/MessageBlobStore.php
new file mode 100644
index 00000000..b262eab6
--- /dev/null
+++ b/www/wiki/includes/cache/MessageBlobStore.php
@@ -0,0 +1,245 @@
+<?php
+/**
+ * Message blobs storage used by ResourceLoader.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ * http://www.gnu.org/copyleft/gpl.html
+ *
+ * @file
+ * @author Roan Kattouw
+ * @author Trevor Parscal
+ * @author Timo Tijhof
+ */
+
+use Psr\Log\LoggerAwareInterface;
+use Psr\Log\LoggerInterface;
+use Psr\Log\NullLogger;
+use Wikimedia\Rdbms\Database;
+
+/**
+ * This class generates message blobs for use by ResourceLoader modules.
+ *
+ * A message blob is a JSON object containing the interface messages for a certain module in
+ * a certain language.
+ */
+class MessageBlobStore implements LoggerAwareInterface {
+
+	/* @var ResourceLoader|null */
+	private $resourceloader;
+
+	/**
+	 * @var LoggerInterface
+	 */
+	protected $logger;
+
+	/**
+	 * @var WANObjectCache
+	 */
+	protected $wanCache;
+
+	/**
+	 * @param ResourceLoader $rl
+	 * @param LoggerInterface $logger
+	 */
+	public function __construct( ResourceLoader $rl = null, LoggerInterface $logger = null ) {
+		$this->resourceloader = $rl;
+		$this->logger = $logger ?: new NullLogger();
+		$this->wanCache = ObjectCache::getMainWANInstance();
+	}
+
+	/**
+	 * @since 1.27
+	 * @param LoggerInterface $logger
+	 */
+	public function setLogger( LoggerInterface $logger ) {
+		$this->logger = $logger;
+	}
+
+	/**
+	 * Get the message blob for a module
+	 *
+	 * @since 1.27
+	 * @param ResourceLoaderModule $module
+	 * @param string $lang Language code
+	 * @return string JSON
+	 */
+	public function getBlob( ResourceLoaderModule $module, $lang ) {
+		$blobs = $this->getBlobs( [ $module->getName() => $module ], $lang );
+		return $blobs[$module->getName()];
+	}
+
+	/**
+	 * Get the message blobs for a set of modules
+	 *
+	 * @since 1.27
+	 * @param ResourceLoaderModule[] $modules Array of module objects keyed by name
+	 * @param string $lang Language code
+	 * @return array An array mapping module names to message blobs
+	 */
+	public function getBlobs( array $modules, $lang ) {
+		// Each cache key for a message blob by module name and language code also has a generic
+		// check key without language code. This is used to invalidate any and all language subkeys
+		// that exist for a module from the updateMessage() method.
+		$cache = $this->wanCache;
+		$checkKeys = [
+			// Global check key, see clear()
+			$cache->makeKey( __CLASS__ )
+		];
+		$cacheKeys = [];
+		foreach ( $modules as $name => $module ) {
+			$cacheKey = $this->makeCacheKey( $module, $lang );
+			$cacheKeys[$name] = $cacheKey;
+			// Per-module check key, see updateMessage()
+			$checkKeys[$cacheKey][] = $cache->makeKey( __CLASS__, $name );
+		}
+		$curTTLs = [];
+		$result = $cache->getMulti( array_values( $cacheKeys ), $curTTLs, $checkKeys );
+
+		$blobs = [];
+		foreach ( $modules as $name => $module ) {
+			$key = $cacheKeys[$name];
+			if ( !isset( $result[$key] ) || $curTTLs[$key] === null || $curTTLs[$key] < 0 ) {
+				$blobs[$name] = $this->recacheMessageBlob( $key, $module, $lang );
+			} else {
+				// Use unexpired cache
+				$blobs[$name] = $result[$key];
+			}
+		}
+		return $blobs;
+	}
+
+	/**
+	 * @deprecated since 1.27 Use getBlobs() instead
+	 * @return array
+	 */
+	public function get( ResourceLoader $resourceLoader, $modules, $lang ) {
+		return $this->getBlobs( $modules, $lang );
+	}
+
+	/**
+	 * @since 1.27
+	 * @param ResourceLoaderModule $module
+	 * @param string $lang
+	 * @return string Cache key
+	 */
+	private function makeCacheKey( ResourceLoaderModule $module, $lang ) {
+		$messages = array_values( array_unique( $module->getMessages() ) );
+		sort( $messages );
+		return $this->wanCache->makeKey( __CLASS__, $module->getName(), $lang,
+			md5( json_encode( $messages ) )
+		);
+	}
+
+	/**
+	 * @since 1.27
+	 * @param string $cacheKey
+	 * @param ResourceLoaderModule $module
+	 * @param string $lang
+	 * @return string JSON blob
+	 */
+	protected function recacheMessageBlob( $cacheKey, ResourceLoaderModule $module, $lang ) {
+		$blob = $this->generateMessageBlob( $module, $lang );
+		$cache = $this->wanCache;
+		$cache->set( $cacheKey, $blob,
+			// Add part of a day to TTL to avoid all modules expiring at once
+			$cache::TTL_WEEK + mt_rand( 0, $cache::TTL_DAY ),
+			Database::getCacheSetOptions( wfGetDB( DB_REPLICA ) )
+		);
+		return $blob;
+	}
+
+	/**
+	 * Invalidate cache keys for modules using this message key.
+	 * Called by MessageCache when a message has changed.
+	 *
+	 * @param string $key Message key
+	 */
+	public function updateMessage( $key ) {
+		$moduleNames = $this->getResourceLoader()->getModulesByMessage( $key );
+		foreach ( $moduleNames as $moduleName ) {
+			// Uses a holdoff to account for database replica DB lag (for MessageCache)
+			$this->wanCache->touchCheckKey( $this->wanCache->makeKey( __CLASS__, $moduleName ) );
+		}
+	}
+
+	/**
+	 * Invalidate cache keys for all known modules.
+	 * Called by LocalisationCache after cache is regenerated.
+	 */
+	public function clear() {
+		$cache = $this->wanCache;
+		// Disable holdoff because this invalidates all modules and also not needed since
+		// LocalisationCache is stored outside the database and doesn't have lag.
+		$cache->touchCheckKey( $cache->makeKey( __CLASS__ ), $cache::HOLDOFF_NONE );
+	}
+
+	/**
+	 * @since 1.27
+	 * @return ResourceLoader
+	 */
+	protected function getResourceLoader() {
+		// Back-compat: This class supports instantiation without a ResourceLoader object.
+		// Lazy-initialise this property because most callers don't need it.
+		if ( $this->resourceloader === null ) {
+			$this->logger->warning( __CLASS__ . ' created without a ResourceLoader instance' );
+			$this->resourceloader = new ResourceLoader();
+		}
+		return $this->resourceloader;
+	}
+
+	/**
+	 * @since 1.27
+	 * @param string $key Message key
+	 * @param string $lang Language code
+	 * @return string
+	 */
+	protected function fetchMessage( $key, $lang ) {
+		$message = wfMessage( $key )->inLanguage( $lang );
+		$value = $message->plain();
+		if ( !$message->exists() ) {
+			$this->logger->warning( 'Failed to find {messageKey} ({lang})', [
+				'messageKey' => $key,
+				'lang' => $lang,
+			] );
+		}
+		return $value;
+	}
+
+	/**
+	 * Generate the message blob for a given module in a given language.
+	 *
+	 * @param ResourceLoaderModule $module
+	 * @param string $lang Language code
+	 * @return string JSON blob
+	 */
+	private function generateMessageBlob( ResourceLoaderModule $module, $lang ) {
+		$messages = [];
+		foreach ( $module->getMessages() as $key ) {
+			$messages[$key] = $this->fetchMessage( $key, $lang );
+		}
+
+		$json = FormatJson::encode( (object)$messages );
+		// @codeCoverageIgnoreStart
+		if ( $json === false ) {
+			$this->logger->warning( 'Failed to encode message blob for {module} ({lang})', [
+				'module' => $module->getName(),
+				'lang' => $lang,
+			] );
+			$json = '{}';
+		}
+		// codeCoverageIgnoreEnd
+		return $json;
+	}
+}