/includes/MessageBlobStore.php
PHP | 358 lines | 197 code | 42 blank | 119 comment | 19 complexity | ce371cdaad10031505e20131193455d6 MD5 | raw file
Possible License(s): GPL-2.0, Apache-2.0, LGPL-3.0
- <?php
- /**
- * 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
- *
- * @author Roan Kattouw
- * @author Trevor Parscal
- */
- /**
- * This class provides access to the resource message blobs storage used by
- * the ResourceLoader.
- *
- * A message blob is a JSON object containing the interface messages for a
- * certain resource in a certain language. These message blobs are cached
- * in the msg_resource table and automatically invalidated when one of their
- * consistuent messages or the resource itself is changed.
- */
- class MessageBlobStore {
- /**
- * Get the message blobs for a set of modules
- *
- * @param $resourceLoader ResourceLoader object
- * @param $modules array Array of module objects keyed by module name
- * @param $lang string Language code
- * @return array An array mapping module names to message blobs
- */
- public static function get( ResourceLoader $resourceLoader, $modules, $lang ) {
- wfProfileIn( __METHOD__ );
- if ( !count( $modules ) ) {
- wfProfileOut( __METHOD__ );
- return array();
- }
- // Try getting from the DB first
- $blobs = self::getFromDB( $resourceLoader, array_keys( $modules ), $lang );
- // Generate blobs for any missing modules and store them in the DB
- $missing = array_diff( array_keys( $modules ), array_keys( $blobs ) );
- foreach ( $missing as $name ) {
- $blob = self::insertMessageBlob( $name, $modules[$name], $lang );
- if ( $blob ) {
- $blobs[$name] = $blob;
- }
- }
- wfProfileOut( __METHOD__ );
- return $blobs;
- }
- /**
- * Generate and insert a new message blob. If the blob was already
- * present, it is not regenerated; instead, the preexisting blob
- * is fetched and returned.
- *
- * @param $name String: module name
- * @param $module ResourceLoaderModule object
- * @param $lang String: language code
- * @return mixed Message blob or false if the module has no messages
- */
- public static function insertMessageBlob( $name, ResourceLoaderModule $module, $lang ) {
- $blob = self::generateMessageBlob( $module, $lang );
- if ( !$blob ) {
- return false;
- }
- $dbw = wfGetDB( DB_MASTER );
- $success = $dbw->insert( 'msg_resource', array(
- 'mr_lang' => $lang,
- 'mr_resource' => $name,
- 'mr_blob' => $blob,
- 'mr_timestamp' => $dbw->timestamp()
- ),
- __METHOD__,
- array( 'IGNORE' )
- );
- if ( $success ) {
- if ( $dbw->affectedRows() == 0 ) {
- // Blob was already present, fetch it
- $blob = $dbw->selectField( 'msg_resource', 'mr_blob', array(
- 'mr_resource' => $name,
- 'mr_lang' => $lang,
- ),
- __METHOD__
- );
- } else {
- // Update msg_resource_links
- $rows = array();
- foreach ( $module->getMessages() as $key ) {
- $rows[] = array(
- 'mrl_resource' => $name,
- 'mrl_message' => $key
- );
- }
- $dbw->insert( 'msg_resource_links', $rows,
- __METHOD__, array( 'IGNORE' )
- );
- }
- }
- return $blob;
- }
- /**
- * Update the message blob for a given module in a given language
- *
- * @param $name String: module name
- * @param $module ResourceLoaderModule object
- * @param $lang String: language code
- * @return String Regenerated message blob, or null if there was no blob for the given module/language pair
- */
- public static function updateModule( $name, ResourceLoaderModule $module, $lang ) {
- $dbw = wfGetDB( DB_MASTER );
- $row = $dbw->selectRow( 'msg_resource', 'mr_blob',
- array( 'mr_resource' => $name, 'mr_lang' => $lang ),
- __METHOD__
- );
- if ( !$row ) {
- return null;
- }
- // Save the old and new blobs for later
- $oldBlob = $row->mr_blob;
- $newBlob = self::generateMessageBlob( $module, $lang );
-
- $newRow = array(
- 'mr_resource' => $name,
- 'mr_lang' => $lang,
- 'mr_blob' => $newBlob,
- 'mr_timestamp' => $dbw->timestamp()
- );
- $dbw->replace( 'msg_resource',
- array( array( 'mr_resource', 'mr_lang' ) ),
- $newRow, __METHOD__
- );
- // Figure out which messages were added and removed
- $oldMessages = array_keys( FormatJson::decode( $oldBlob, true ) );
- $newMessages = array_keys( FormatJson::decode( $newBlob, true ) );
- $added = array_diff( $newMessages, $oldMessages );
- $removed = array_diff( $oldMessages, $newMessages );
- // Delete removed messages, insert added ones
- if ( $removed ) {
- $dbw->delete( 'msg_resource_links', array(
- 'mrl_resource' => $name,
- 'mrl_message' => $removed
- ), __METHOD__
- );
- }
- $newLinksRows = array();
- foreach ( $added as $message ) {
- $newLinksRows[] = array(
- 'mrl_resource' => $name,
- 'mrl_message' => $message
- );
- }
- if ( $newLinksRows ) {
- $dbw->insert( 'msg_resource_links', $newLinksRows, __METHOD__,
- array( 'IGNORE' ) // just in case
- );
- }
- return $newBlob;
- }
- /**
- * Update a single message in all message blobs it occurs in.
- *
- * @param $key String: message key
- */
- public static function updateMessage( $key ) {
- $dbw = wfGetDB( DB_MASTER );
- // Keep running until the updates queue is empty.
- // Due to update conflicts, the queue might not be emptied
- // in one iteration.
- $updates = null;
- do {
- $updates = self::getUpdatesForMessage( $key, $updates );
- foreach ( $updates as $k => $update ) {
- // Update the row on the condition that it
- // didn't change since we fetched it by putting
- // the timestamp in the WHERE clause.
- $success = $dbw->update( 'msg_resource',
- array(
- 'mr_blob' => $update['newBlob'],
- 'mr_timestamp' => $dbw->timestamp() ),
- array(
- 'mr_resource' => $update['resource'],
- 'mr_lang' => $update['lang'],
- 'mr_timestamp' => $update['timestamp'] ),
- __METHOD__
- );
- // Only requeue conflicted updates.
- // If update() returned false, don't retry, for
- // fear of getting into an infinite loop
- if ( !( $success && $dbw->affectedRows() == 0 ) ) {
- // Not conflicted
- unset( $updates[$k] );
- }
- }
- } while ( count( $updates ) );
- // No need to update msg_resource_links because we didn't add
- // or remove any messages, we just changed their contents.
- }
- public static function clear() {
- // TODO: Give this some more thought
- // TODO: Is TRUNCATE better?
- $dbw = wfGetDB( DB_MASTER );
- $dbw->delete( 'msg_resource', '*', __METHOD__ );
- $dbw->delete( 'msg_resource_links', '*', __METHOD__ );
- }
- /**
- * Create an update queue for updateMessage()
- *
- * @param $key String: message key
- * @param $prevUpdates Array: updates queue to refresh or null to build a fresh update queue
- * @return Array: updates queue
- */
- private static function getUpdatesForMessage( $key, $prevUpdates = null ) {
- $dbw = wfGetDB( DB_MASTER );
- if ( is_null( $prevUpdates ) ) {
- // Fetch all blobs referencing $key
- $res = $dbw->select(
- array( 'msg_resource', 'msg_resource_links' ),
- array( 'mr_resource', 'mr_lang', 'mr_blob', 'mr_timestamp' ),
- array( 'mrl_message' => $key, 'mr_resource=mrl_resource' ),
- __METHOD__
- );
- } else {
- // Refetch the blobs referenced by $prevUpdates
- // Reorganize the (resource, lang) pairs in the format
- // expected by makeWhereFrom2d()
- $twoD = array();
- foreach ( $prevUpdates as $update ) {
- $twoD[$update['resource']][$update['lang']] = true;
- }
- $res = $dbw->select( 'msg_resource',
- array( 'mr_resource', 'mr_lang', 'mr_blob', 'mr_timestamp' ),
- $dbw->makeWhereFrom2d( $twoD, 'mr_resource', 'mr_lang' ),
- __METHOD__
- );
- }
- // Build the new updates queue
- $updates = array();
- foreach ( $res as $row ) {
- $updates[] = array(
- 'resource' => $row->mr_resource,
- 'lang' => $row->mr_lang,
- 'timestamp' => $row->mr_timestamp,
- 'newBlob' => self::reencodeBlob( $row->mr_blob, $key, $row->mr_lang )
- );
- }
- return $updates;
- }
- /**
- * Reencode a message blob with the updated value for a message
- *
- * @param $blob String: message blob (JSON object)
- * @param $key String: message key
- * @param $lang String: language code
- * @return Message blob with $key replaced with its new value
- */
- private static function reencodeBlob( $blob, $key, $lang ) {
- $decoded = FormatJson::decode( $blob, true );
- $decoded[$key] = wfMsgExt( $key, array( 'language' => $lang ) );
- return FormatJson::encode( (object)$decoded );
- }
- /**
- * Get the message blobs for a set of modules from the database.
- * Modules whose blobs are not in the database are silently dropped.
- *
- * @param $resourceLoader ResourceLoader object
- * @param $modules Array of module names
- * @param $lang String: language code
- * @return array Array mapping module names to blobs
- */
- private static function getFromDB( ResourceLoader $resourceLoader, $modules, $lang ) {
- global $wgCacheEpoch;
- $retval = array();
- $dbr = wfGetDB( DB_SLAVE );
- $res = $dbr->select( 'msg_resource',
- array( 'mr_blob', 'mr_resource', 'mr_timestamp' ),
- array( 'mr_resource' => $modules, 'mr_lang' => $lang ),
- __METHOD__
- );
- foreach ( $res as $row ) {
- $module = $resourceLoader->getModule( $row->mr_resource );
- if ( !$module ) {
- // This shouldn't be possible
- throw new MWException( __METHOD__ . ' passed an invalid module name' );
- }
- // Update the module's blobs if the set of messages changed or if the blob is
- // older than $wgCacheEpoch
- if ( array_keys( FormatJson::decode( $row->mr_blob, true ) ) !== array_values( array_unique( $module->getMessages() ) ) ||
- wfTimestamp( TS_MW, $row->mr_timestamp ) <= $wgCacheEpoch ) {
- $retval[$row->mr_resource] = self::updateModule( $row->mr_resource, $module, $lang );
- } else {
- $retval[$row->mr_resource] = $row->mr_blob;
- }
- }
- return $retval;
- }
- /**
- * Generate the message blob for a given module in a given language.
- *
- * @param $module ResourceLoaderModule object
- * @param $lang String: language code
- * @return String: JSON object
- */
- private static function generateMessageBlob( ResourceLoaderModule $module, $lang ) {
- $messages = array();
- foreach ( $module->getMessages() as $key ) {
- $messages[$key] = wfMsgExt( $key, array( 'language' => $lang ) );
- }
- return FormatJson::encode( (object)$messages );
- }
- }