Current File : //data/www_bck/varak.net_bck/havranipapuce.varak.net/includes/MessageBlobStore.php
<?php
/**
* Resource message blobs storage used by the resource loader.
*
* 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
*/
/**
* 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
* constituent messages or the resource itself is changed.
*/
class MessageBlobStore {
/**
* Get the singleton instance
*
* @since 1.24
* @deprecated since 1.25
* @return MessageBlobStore
*/
public static function getInstance() {
wfDeprecated( __METHOD__, '1.25' );
return new self;
}
/**
* Get the message blobs for a set of modules
*
* @param ResourceLoader $resourceLoader
* @param array $modules Array of module objects keyed by module name
* @param string $lang Language code
* @return array An array mapping module names to message blobs
*/
public function get( ResourceLoader $resourceLoader, $modules, $lang ) {
if ( !count( $modules ) ) {
return array();
}
// Try getting from the DB first
$blobs = $this->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 = $this->insertMessageBlob( $name, $modules[$name], $lang );
if ( $blob ) {
$blobs[$name] = $blob;
}
}
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 string $name Module name
* @param ResourceLoaderModule $module
* @param string $lang Language code
* @return mixed Message blob or false if the module has no messages
*/
public function insertMessageBlob( $name, ResourceLoaderModule $module, $lang ) {
$blob = $this->generateMessageBlob( $module, $lang );
if ( !$blob ) {
return false;
}
try {
$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' )
);
}
}
} catch ( DBError $e ) {
wfDebug( __METHOD__ . " failed to update DB: $e\n" );
}
return $blob;
}
/**
* Update the message blob for a given module in a given language
*
* @param string $name Module name
* @param ResourceLoaderModule $module
* @param string $lang Language code
* @return string Regenerated message blob, or null if there was no blob for
* the given module/language pair.
*/
public 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 = $this->generateMessageBlob( $module, $lang );
try {
$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
);
}
} catch ( Exception $e ) {
wfDebug( __METHOD__ . " failed to update DB: $e\n" );
}
return $newBlob;
}
/**
* Update a single message in all message blobs it occurs in.
*
* @param string $key Message key
*/
public function updateMessage( $key ) {
try {
$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 = $this->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.
} catch ( Exception $e ) {
wfDebug( __METHOD__ . " failed to update DB: $e\n" );
}
}
public function clear() {
// TODO: Give this some more thought
try {
// Not using TRUNCATE, because that needs extra permissions,
// which maybe not granted to the database user.
$dbw = wfGetDB( DB_MASTER );
$dbw->delete( 'msg_resource', '*', __METHOD__ );
$dbw->delete( 'msg_resource_links', '*', __METHOD__ );
} catch ( Exception $e ) {
wfDebug( __METHOD__ . " failed to update DB: $e\n" );
}
}
/**
* Create an update queue for updateMessage()
*
* @param string $key Message key
* @param array $prevUpdates Updates queue to refresh or null to build a fresh update queue
* @return array Updates queue
*/
private 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' => $this->reencodeBlob( $row->mr_blob, $key, $row->mr_lang )
);
}
return $updates;
}
/**
* Reencode a message blob with the updated value for a message
*
* @param string $blob Message blob (JSON object)
* @param string $key Message key
* @param string $lang Language code
* @return string Message blob with $key replaced with its new value
*/
private function reencodeBlob( $blob, $key, $lang ) {
$decoded = FormatJson::decode( $blob, true );
$decoded[$key] = wfMessage( $key )->inLanguage( $lang )->plain();
return FormatJson::encode( (object)$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
* @param array $modules Array of module names
* @param string $lang Language code
* @throws MWException
* @return array Array mapping module names to blobs
*/
private function getFromDB( ResourceLoader $resourceLoader, $modules, $lang ) {
$config = $resourceLoader->getConfig();
$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 the CacheEpoch setting
$keys = array_keys( FormatJson::decode( $row->mr_blob, true ) );
$values = array_values( array_unique( $module->getMessages() ) );
if ( $keys !== $values
|| wfTimestamp( TS_MW, $row->mr_timestamp ) <= $config->get( 'CacheEpoch' )
) {
$retval[$row->mr_resource] = $this->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 ResourceLoaderModule $module
* @param string $lang Language code
* @return string JSON object
*/
private function generateMessageBlob( ResourceLoaderModule $module, $lang ) {
$messages = array();
foreach ( $module->getMessages() as $key ) {
$messages[$key] = wfMessage( $key )->inLanguage( $lang )->plain();
}
return FormatJson::encode( (object)$messages );
}
}
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