summaryrefslogtreecommitdiff
path: root/includes/MessageBlobStore.php
diff options
context:
space:
mode:
Diffstat (limited to 'includes/MessageBlobStore.php')
-rw-r--r--includes/MessageBlobStore.php370
1 files changed, 370 insertions, 0 deletions
diff --git a/includes/MessageBlobStore.php b/includes/MessageBlobStore.php
new file mode 100644
index 00000000..5e6c8e5e
--- /dev/null
+++ b/includes/MessageBlobStore.php
@@ -0,0 +1,370 @@
+<?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 all message blobs for a given module.
+ *
+ * @param $name String: module name
+ * @param $module ResourceLoaderModule object
+ * @param $lang String: language code (optional)
+ * @return Mixed: if $lang is set, the new message blob for that language is
+ * returned if present. Otherwise, null is returned.
+ */
+ public static function updateModule( $name, ResourceLoaderModule $module, $lang = null ) {
+ $retval = null;
+
+ // Find all existing blobs for this module
+ $dbw = wfGetDB( DB_MASTER );
+ $res = $dbw->select( 'msg_resource',
+ array( 'mr_lang', 'mr_blob' ),
+ array( 'mr_resource' => $name ),
+ __METHOD__
+ );
+
+ // Build the new msg_resource rows
+ $newRows = array();
+ $now = $dbw->timestamp();
+ // Save the last-processed old and new blobs for later
+ $oldBlob = $newBlob = null;
+
+ foreach ( $res as $row ) {
+ $oldBlob = $row->mr_blob;
+ $newBlob = self::generateMessageBlob( $module, $row->mr_lang );
+
+ if ( $row->mr_lang === $lang ) {
+ $retval = $newBlob;
+ }
+ $newRows[] = array(
+ 'mr_resource' => $name,
+ 'mr_lang' => $row->mr_lang,
+ 'mr_blob' => $newBlob,
+ 'mr_timestamp' => $now
+ );
+ }
+
+ $dbw->replace( 'msg_resource',
+ array( array( 'mr_resource', 'mr_lang' ) ),
+ $newRows, __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 $retval;
+ }
+
+ /**
+ * 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 ) ) !== $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 );
+ }
+}