+
+ /**
+ * Checks if there is a redirect named as $title
+ *
+ * @param Title $title Title of image
+ */
+ function checkRedirect( $title ) {
+ global $wgMemc;
+
+ if( is_string( $title ) ) {
+ $title = Title::newFromTitle( $title );
+ }
+ if( $title instanceof Title && $title->getNamespace() == NS_MEDIA ) {
+ $title = Title::makeTitle( NS_FILE, $title->getText() );
+ }
+
+ $memcKey = $this->getSharedCacheKey( 'image_redirect', md5( $title->getDBkey() ) );
+ if ( $memcKey === false ) {
+ $memcKey = $this->getLocalCacheKey( 'image_redirect', md5( $title->getDBkey() ) );
+ $expiry = 300; // no invalidation, 5 minutes
+ } else {
+ $expiry = 86400; // has invalidation, 1 day
+ }
+ $cachedValue = $wgMemc->get( $memcKey );
+ if ( $cachedValue === ' ' || $cachedValue === '' ) {
+ // Does not exist
+ return false;
+ } elseif ( strval( $cachedValue ) !== '' ) {
+ return Title::newFromText( $cachedValue, NS_FILE );
+ } // else $cachedValue is false or null: cache miss
+
+ $id = $this->getArticleID( $title );
+ if( !$id ) {
+ $wgMemc->set( $memcKey, " ", $expiry );
+ return false;
+ }
+ $dbr = $this->getSlaveDB();
+ $row = $dbr->selectRow(
+ 'redirect',
+ array( 'rd_title', 'rd_namespace' ),
+ array( 'rd_from' => $id ),
+ __METHOD__
+ );
+
+ if( $row && $row->rd_namespace == NS_FILE ) {
+ $targetTitle = Title::makeTitle( $row->rd_namespace, $row->rd_title );
+ $wgMemc->set( $memcKey, $targetTitle->getDBkey(), $expiry );
+ return $targetTitle;
+ } else {
+ $wgMemc->set( $memcKey, '', $expiry );
+ return false;
+ }
+ }
+
+
+ /**
+ * Function link Title::getArticleID().
+ * We can't say Title object, what database it should use, so we duplicate that function here.
+ */
+ protected function getArticleID( $title ) {
+ if( !$title instanceof Title ) {
+ return 0;
+ }
+ $dbr = $this->getSlaveDB();
+ $id = $dbr->selectField(
+ 'page', // Table
+ 'page_id', //Field
+ array( //Conditions
+ 'page_namespace' => $title->getNamespace(),
+ 'page_title' => $title->getDBkey(),
+ ),
+ __METHOD__ //Function name
+ );
+ return $id;
+ }
+
+ /**
+ * Get an array or iterator of file objects for files that have a given
+ * SHA-1 content hash.
+ */
+ function findBySha1( $hash ) {
+ $dbr = $this->getSlaveDB();
+ $res = $dbr->select(
+ 'image',
+ LocalFile::selectFields(),
+ array( 'img_sha1' => $hash )
+ );
+
+ $result = array();
+ while ( $row = $res->fetchObject() )
+ $result[] = $this->newFileFromRow( $row );
+ $res->free();
+ return $result;
+ }
+
+ /**
+ * Get a connection to the slave DB
+ */
+ function getSlaveDB() {
+ return wfGetDB( DB_SLAVE );
+ }
+
+ /**
+ * Get a connection to the master DB
+ */
+ function getMasterDB() {
+ return wfGetDB( DB_MASTER );
+ }
+
+ /**
+ * Get a key on the primary cache for this repository.
+ * Returns false if the repository's cache is not accessible at this site.
+ * The parameters are the parts of the key, as for wfMemcKey().
+ */
+ function getSharedCacheKey( /*...*/ ) {
+ $args = func_get_args();
+ return call_user_func_array( 'wfMemcKey', $args );
+ }
+
+ /**
+ * Invalidates image redirect cache related to that image
+ *
+ * @param Title $title Title of image
+ */
+ function invalidateImageRedirect( $title ) {
+ global $wgMemc;
+ $memcKey = $this->getSharedCacheKey( 'image_redirect', md5( $title->getDBkey() ) );
+ if ( $memcKey ) {
+ $wgMemc->delete( $memcKey );
+ }
+ }