DynamicPageList3/includes/RevisionJoinBuilder.php

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2021-10-01 22:52:30 +00:00
<?php
namespace DPL;
use ActorMigration;
use CommentStore;
use Wikimedia\Rdbms\IDatabase;
class RevisionJoinBuilder {
/** @var IDatabase */
private $dbr;
/** @var ActorMigration */
private $actorMigration;
/** @var CommentStore */
private $commentStore;
/**
* List of fields to select from the first revision of the article, keyed by alias.
* @var string[]
*/
private $firstRevisionFields = [];
/**
* List of fields to select from the last revision of the article, keyed by alias.
* @var string[]
*/
private $lastRevisionFields = [];
public function __construct(
IDatabase $dbr,
ActorMigration $actorMigration,
CommentStore $commentStore
) {
$this->dbr = $dbr;
$this->actorMigration = $actorMigration;
$this->commentStore = $commentStore;
}
public function addFieldsFromFirst( array $fields ): void {
$this->firstRevisionFields += $fields;
}
public function addFieldsFromLast( array $fields ): void {
$this->lastRevisionFields += $fields;
}
public function getQueryInfo(): array {
$queryInfo = [
'fields' => [],
'tables' => [],
'joins' => [],
];
return array_merge_recursive(
$queryInfo,
$this->addRevisionQueryInfo(
'latest_rev',
$this->lastRevisionFields,
[ 'rev_id=page_latest' ]
),
$this->addRevisionQueryInfo(
'first_rev',
$this->firstRevisionFields,
[
// @phan-suppress-next-line PhanPluginMixedKeyNoKey
'rev_page=page_id',
'rev_parent_id' => 0,
]
)
);
}
private function addRevisionQueryInfo(
string $tableAlias,
array $fieldsByAlias,
array $joinConds
): array {
if ( !$fieldsByAlias ) {
return [];
}
$fieldsByAlias += [ 'rev_id', 'rev_page', 'rev_parent_id' ];
$actorQuery = $this->actorMigration->getJoin( 'rev_user' );
$commentQuery = $this->commentStore->getJoin( 'rev_comment' );
// Ensure we correctly fetch aliased fields such as rev_user
// from the revision_actor_temp table if it is active.
$actorFields = array_keys( $actorQuery['fields'] );
$revFields = array_diff( $fieldsByAlias, $actorFields );
// Since multiple instances of the revision and associated actor tables may be used per
// query, join on the derived result of an aliased subquery to avoid naming conflicts.
$revQuery = $this->dbr->buildSelectSubquery(
[ $tableAlias => 'revision' ] + $actorQuery['tables'] + $commentQuery['tables'],
$actorQuery['fields'] + $commentQuery['fields'] + array_values( $revFields ),
[],
__METHOD__,
[],
$actorQuery['joins'] + $commentQuery['joins']
);
$fieldsWithPrefix = [];
$quotedTableAlias = $this->dbr->addIdentifierQuotes( $tableAlias );
foreach ( $fieldsByAlias as $alias => $revFieldName ) {
$quotedRevField = $this->dbr->addIdentifierQuotes( $revFieldName );
$fieldsWithPrefix[$alias] = "$quotedTableAlias.$quotedRevField";
}
return [
'fields' => $fieldsWithPrefix,
'tables' => [
$tableAlias => $revQuery
],
'joins' => [
$tableAlias => [ 'JOIN', $joinConds ]
]
];
}
}