mediawiki-extensions-Discus.../includes/ThreadItemStore.php

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<?php
namespace MediaWiki\Extension\DiscussionTools;
use Config;
use ConfigFactory;
use MediaWiki\Extension\DiscussionTools\ThreadItem\CommentItem;
use MediaWiki\Extension\DiscussionTools\ThreadItem\DatabaseCommentItem;
use MediaWiki\Extension\DiscussionTools\ThreadItem\DatabaseHeadingItem;
use MediaWiki\Extension\DiscussionTools\ThreadItem\DatabaseThreadItem;
use MediaWiki\Extension\DiscussionTools\ThreadItem\HeadingItem;
use MediaWiki\Page\PageStore;
use MediaWiki\Revision\RevisionRecord;
use MediaWiki\Revision\RevisionStore;
use MediaWiki\User\ActorStore;
use MWTimestamp;
use ReadOnlyMode;
use stdClass;
use TitleFormatter;
use Wikimedia\Rdbms\ILBFactory;
use Wikimedia\Rdbms\ILoadBalancer;
use Wikimedia\Rdbms\IResultWrapper;
use Wikimedia\Rdbms\SelectQueryBuilder;
/**
* Stores and fetches ThreadItemSets from the database.
*/
class ThreadItemStore {
private Config $config;
private ILoadBalancer $loadBalancer;
private ReadOnlyMode $readOnlyMode;
private PageStore $pageStore;
private RevisionStore $revStore;
private TitleFormatter $titleFormatter;
private ActorStore $actorStore;
public function __construct(
ConfigFactory $configFactory,
ILBFactory $lbFactory,
ReadOnlyMode $readOnlyMode,
PageStore $pageStore,
RevisionStore $revStore,
TitleFormatter $titleFormatter,
ActorStore $actorStore
) {
$this->config = $configFactory->makeConfig( 'discussiontools' );
$this->loadBalancer = $lbFactory->getMainLB();
$this->readOnlyMode = $readOnlyMode;
$this->pageStore = $pageStore;
$this->revStore = $revStore;
$this->titleFormatter = $titleFormatter;
$this->actorStore = $actorStore;
}
/**
* Returns true if the tables necessary for this feature haven't been created yet,
* to allow failing softly in that case.
*
* @return bool
*/
private function isDisabled(): bool {
return !$this->config->get( 'DiscussionToolsEnablePermalinksBackend' );
}
/**
* Find the thread items with the given name in the newest revision of every page in which they
* have appeared.
*
* @param string|string[] $itemName
* @return DatabaseThreadItem[]
*/
public function findNewestRevisionsByName( $itemName ): array {
if ( $this->isDisabled() ) {
return [];
}
$queryBuilder = $this->getIdsNamesBuilder()
->where( [
'it_itemname' => $itemName,
// Disallow querying for headings of sections that contain no comments.
// They all share the same name, so this would return a huge useless list on most wikis.
// (But we still store them, as we might need this data elsewhere.)
"it_itemname != 'h-'",
] );
$result = $this->fetchItemsResultSet( $queryBuilder );
$revs = $this->fetchRevisionAndPageForItems( $result );
$threadItems = [];
foreach ( $result as $row ) {
$threadItem = $this->getThreadItemFromRow( $row, null, $revs );
if ( $threadItem ) {
$threadItems[] = $threadItem;
}
}
return $threadItems;
}
/**
* Find the thread items with the given ID in the newest revision of every page in which they have
* appeared.
*
* @param string|string[] $itemId
* @return DatabaseThreadItem[]
*/
public function findNewestRevisionsById( $itemId ): array {
if ( $this->isDisabled() ) {
return [];
}
$queryBuilder = $this->getIdsNamesBuilder();
// First find the name associated with the ID; then find by name. Otherwise we wouldn't find the
// latest revision in case comment ID changed, e.g. the comment was moved elsewhere on the page.
$itemNameQueryBuilder = $this->getIdsNamesBuilder()
->where( [ 'itid_itemid' => $itemId ] )
->field( 'it_itemname' );
// I think there may be more than 1 only in case of headings?
// For comments, any ID corresponds to just 1 name.
// Not sure how bad it is to not have limit( 1 ) here?
// It might scan a bunch of rows...
// ->limit( 1 );
$queryBuilder
->where( [
'it_itemname IN (' . $itemNameQueryBuilder->getSQL() . ')',
"it_itemname != 'h-'",
] );
$result = $this->fetchItemsResultSet( $queryBuilder );
$revs = $this->fetchRevisionAndPageForItems( $result );
$threadItems = [];
foreach ( $result as $row ) {
$threadItem = $this->getThreadItemFromRow( $row, null, $revs );
if ( $threadItem ) {
$threadItems[] = $threadItem;
}
}
return $threadItems;
}
/**
* @param SelectQueryBuilder $queryBuilder
* @return IResultWrapper
*/
private function fetchItemsResultSet( SelectQueryBuilder $queryBuilder ): IResultWrapper {
$queryBuilder
->fields( [
'itr_id',
'it_itemname',
'it_timestamp',
'it_actor',
'itid_itemid',
'itr_parent_id',
'itr_transcludedfrom',
'itr_level',
'itr_headinglevel',
'itr_revision_id',
] )
// PageStore fields for the transcluded-from page
->leftJoin( 'page', null, [ 'page_id = itr_transcludedfrom' ] )
->fields( $this->pageStore->getSelectFields() )
// ActorStore fields for the author
->leftJoin( 'actor', null, [ 'actor_id = it_actor' ] )
->fields( [ 'actor_id', 'actor_name', 'actor_user' ] )
// Parent item ID (the string, not just the primary key)
->leftJoin(
$this->getIdsNamesBuilder()
->fields( [
'itr_parent__itr_id' => 'itr_id',
'itr_parent__itid_itemid' => 'itid_itemid',
] ),
null,
[ 'itr_parent_id = itr_parent__itr_id' ]
)
->field( 'itr_parent__itid_itemid' );
return $queryBuilder->fetchResultSet();
}
/**
* @param IResultWrapper $result
* @return stdClass[]
*/
private function fetchRevisionAndPageForItems( IResultWrapper $result ): array {
// This could theoretically be done in the same query as fetchItemsResultSet(),
// but the resulting query would be two screens long
// and we'd have to alias a lot of fields to avoid conflicts.
$revs = [];
foreach ( $result as $row ) {
$revs[ $row->itr_revision_id ] = null;
}
$revQueryBuilder = $this->loadBalancer->getConnection( DB_REPLICA )->newSelectQueryBuilder()
->queryInfo( $this->revStore->getQueryInfo( [ 'page' ] ) )
->fields( $this->pageStore->getSelectFields() )
->where( $revs ? [ 'rev_id' => array_keys( $revs ) ] : '0=1' );
$revResult = $revQueryBuilder->fetchResultSet();
foreach ( $revResult as $row ) {
$revs[ $row->rev_id ] = $row;
}
return $revs;
}
/**
* @param stdClass $row
* @param DatabaseThreadItemSet|null $set
* @param array $revs
* @return DatabaseThreadItem|null
*/
private function getThreadItemFromRow(
stdClass $row, ?DatabaseThreadItemSet $set, array $revs
): ?DatabaseThreadItem {
if ( $revs[ $row->itr_revision_id ] === null ) {
// We didn't find the 'revision' table row at all, this revision is deleted.
// (The page may or may not have other non-deleted revisions.)
// Pretend the thread item doesn't exist to avoid leaking data to users who shouldn't see it.
// TODO Allow privileged users to see it (we'd need to query from 'archive')
return null;
}
$revRow = $revs[$row->itr_revision_id];
$page = $this->pageStore->newPageRecordFromRow( $revRow );
$rev = $this->revStore->newRevisionFromRow( $revRow );
if ( $rev->isDeleted( RevisionRecord::DELETED_TEXT ) ) {
// This revision is revision-deleted.
// TODO Allow privileged users to see it
return null;
}
if ( $set && $row->itr_parent__itid_itemid ) {
$parent = $set->findCommentById( $row->itr_parent__itid_itemid );
} else {
$parent = null;
}
$transcludedFrom = $row->itr_transcludedfrom === null ? false : (
$row->itr_transcludedfrom === '0' ? true :
$this->titleFormatter->getPrefixedText(
$this->pageStore->newPageRecordFromRow( $row )
)
);
if ( $row->it_timestamp !== null && $row->it_actor !== null ) {
$author = $this->actorStore->newActorFromRow( $row )->getName();
$item = new DatabaseCommentItem(
$page,
$rev,
$row->it_itemname,
$row->itid_itemid,
$parent,
$transcludedFrom,
(int)$row->itr_level,
$row->it_timestamp,
$author
);
} else {
$item = new DatabaseHeadingItem(
$page,
$rev,
$row->it_itemname,
$row->itid_itemid,
$parent,
$transcludedFrom,
(int)$row->itr_level,
$row->itr_headinglevel === null ? null : (int)$row->itr_headinglevel
);
}
if ( $parent ) {
$parent->addReply( $item );
}
return $item;
}
/**
* Find the thread item set for the given revision, assuming that it is the current revision of
* its page.
*
* @param int $revId
* @return DatabaseThreadItemSet
*/
public function findThreadItemsInCurrentRevision( int $revId ): DatabaseThreadItemSet {
if ( $this->isDisabled() ) {
return new DatabaseThreadItemSet();
}
$queryBuilder = $this->getIdsNamesBuilder();
$queryBuilder
->where( [ 'itr_revision_id' => $revId ] )
// We must process parents before their children in the loop later
->orderBy( 'itr_id', SelectQueryBuilder::SORT_ASC );
$result = $this->fetchItemsResultSet( $queryBuilder );
$revs = $this->fetchRevisionAndPageForItems( $result );
$set = new DatabaseThreadItemSet();
foreach ( $result as $row ) {
$threadItem = $this->getThreadItemFromRow( $row, $set, $revs );
if ( $threadItem ) {
$set->addThreadItem( $threadItem );
$set->updateIdAndNameMaps( $threadItem );
}
}
return $set;
}
/**
* @return SelectQueryBuilder
*/
private function getIdsNamesBuilder(): SelectQueryBuilder {
$dbr = $this->loadBalancer->getConnection( DB_REPLICA );
$queryBuilder = $dbr->newSelectQueryBuilder()
->from( 'discussiontools_items' )
->join( 'discussiontools_item_pages', null, [ 'itp_items_id = it_id' ] )
->join( 'discussiontools_item_revisions', null, [
'itr_items_id = it_id',
// Only the latest revision of the items with each name
'itr_revision_id = itp_newest_revision_id',
] )
->join( 'discussiontools_item_ids', null, [ 'itid_id = itr_itemid_id' ] );
return $queryBuilder;
}
/**
* Store the thread item set.
*
* @param RevisionRecord $rev
* @param ThreadItemSet $threadItemSet
* @return bool
*/
public function insertThreadItems( RevisionRecord $rev, ThreadItemSet $threadItemSet ): bool {
if ( $this->isDisabled() || $this->readOnlyMode->isReadOnly() ) {
return false;
}
$dbw = $this->loadBalancer->getConnection( DB_PRIMARY );
$didInsert = false;
$method = __METHOD__;
// Map of item IDs (strings) to their discussiontools_item_ids.itid_id field values (ints)
$itemIdsIds = [];
'@phan-var array<string,int> $itemIdsIds';
// Map of item IDs (strings) to their discussiontools_items.it_id field values (ints)
$itemsIds = [];
'@phan-var array<string,int> $itemsIds';
// Insert or find discussiontools_item_ids rows, fill in itid_id field values.
// (This is not in a transaction. Orphaned rows in this table are harmlessly ignored,
// and long transactions caused performance issues on Wikimedia wikis: T315353#8218914.)
foreach ( $threadItemSet->getThreadItems() as $item ) {
$itemIdsId = $dbw->newSelectQueryBuilder()
->from( 'discussiontools_item_ids' )
->field( 'itid_id' )
->where( [ 'itid_itemid' => $item->getId() ] )
->caller( $method )
->fetchField();
if ( $itemIdsId === false ) {
// Use upsert() instead of insert() to handle race conditions (T322701).
// Do a SELECT first to avoid unnecessary replication and bumping auto-increment values.
// (We can't just use INSERT IGNORE and then do a SELECT because of implicit
// transactions with REPEATABLE READ.)
$dbw->upsert(
'discussiontools_item_ids',
[
'itid_itemid' => $item->getId(),
],
'itid_itemid',
// We update nothing, as the rows will be identical, but this can't be empty
[ 'itid_id = itid_id' ],
$method
);
$itemIdsId = $dbw->insertId();
$didInsert = true;
}
$itemIdsIds[ $item->getId() ] = $itemIdsId;
}
// Insert or find discussiontools_items rows, fill in it_id field values.
// (This is not in a transaction. Orphaned rows in this table are harmlessly ignored,
// and long transactions caused performance issues on Wikimedia wikis: T315353#8218914.)
foreach ( $threadItemSet->getThreadItems() as $item ) {
$itemsId = $dbw->newSelectQueryBuilder()
->from( 'discussiontools_items' )
->field( 'it_id' )
->where( [ 'it_itemname' => $item->getName() ] )
->caller( $method )
->fetchField();
if ( $itemsId === false ) {
// Use upsert() instead of insert() to handle race conditions (T322701).
// Do a SELECT first to avoid unnecessary replication and bumping auto-increment values.
// (We can't just use INSERT IGNORE and then do a SELECT because of implicit
// transactions with REPEATABLE READ.)
$dbw->upsert(
'discussiontools_items',
[
'it_itemname' => $item->getName(),
] +
( $item instanceof CommentItem ? [
'it_timestamp' =>
$dbw->timestamp( $item->getTimestampString() ),
'it_actor' =>
$this->actorStore->findActorIdByName( $item->getAuthor(), $dbw ),
] : [] ),
'it_itemname',
// We update nothing, as the rows will be identical, but this can't be empty
[ 'it_id = it_id' ],
$method
);
$itemsId = $dbw->insertId();
$didInsert = true;
}
$itemsIds[ $item->getId() ] = $itemsId;
}
// Insert or update discussiontools_item_pages and discussiontools_item_revisions rows.
// This IS in a transaction. We don't really want rows for different items on the same
// page to point to different revisions.
$dbw->doAtomicSection( $method, function ( $dbw ) use (
$method, $rev, $threadItemSet, $itemsIds, $itemIdsIds, &$didInsert
) {
// Map of item IDs (strings) to their discussiontools_item_revisions.itr_id field values (ints)
$itemRevisionsIds = [];
'@phan-var array<string,int> $itemRevisionsIds';
$revUpdateRows = [];
// Insert or update discussiontools_item_pages rows.
foreach ( $threadItemSet->getThreadItems() as $item ) {
// Update (or insert) the references to oldest/newest item revision.
// The page revision we're processing is usually the newest one, but it doesn't have to be
// (in case of backfilling using the maintenance script, or in case of revisions being
// imported), so we need all these funky queries to see if we need to update oldest/newest.
$itemPagesRow = $dbw->newSelectQueryBuilder()
->from( 'discussiontools_item_pages' )
->join( 'revision', 'revision_oldest', [ 'itp_oldest_revision_id = revision_oldest.rev_id' ] )
->join( 'revision', 'revision_newest', [ 'itp_newest_revision_id = revision_newest.rev_id' ] )
->field( 'itp_id' )
->field( 'itp_oldest_revision_id' )
->field( 'itp_newest_revision_id' )
->field( 'revision_oldest.rev_timestamp', 'oldest_rev_timestamp' )
->field( 'revision_newest.rev_timestamp', 'newest_rev_timestamp' )
->where( [
'itp_items_id' => $itemsIds[ $item->getId() ],
'itp_page_id' => $rev->getPageId(),
] )
->fetchRow();
if ( $itemPagesRow === false ) {
$dbw->insert(
'discussiontools_item_pages',
[
'itp_items_id' => $itemsIds[ $item->getId() ],
'itp_page_id' => $rev->getPageId(),
'itp_oldest_revision_id' => $rev->getId(),
'itp_newest_revision_id' => $rev->getId(),
],
$method
);
} else {
$oldestTime = ( new MWTimestamp( $itemPagesRow->oldest_rev_timestamp ) )->getTimestamp( TS_MW );
$newestTime = ( new MWTimestamp( $itemPagesRow->newest_rev_timestamp ) )->getTimestamp( TS_MW );
$currentTime = $rev->getTimestamp();
$oldestId = (int)$itemPagesRow->itp_oldest_revision_id;
$newestId = (int)$itemPagesRow->itp_newest_revision_id;
$currentId = $rev->getId();
$updatePageField = null;
if ( [ $oldestTime, $oldestId ] > [ $currentTime, $currentId ] ) {
$updatePageField = 'itp_oldest_revision_id';
} elseif ( [ $newestTime, $newestId ] < [ $currentTime, $currentId ] ) {
$updatePageField = 'itp_newest_revision_id';
}
if ( $updatePageField ) {
$dbw->update(
'discussiontools_item_pages',
[ $updatePageField => $rev->getId() ],
[ 'itp_id' => $itemPagesRow->itp_id ],
$method
);
if ( $oldestId !== $newestId ) {
// This causes most rows in discussiontools_item_revisions referring to the previously
// oldest/newest revision to be unused, so try re-using them.
$revUpdateRows[ $itemsIds[ $item->getId() ] ] = $itemPagesRow->$updatePageField;
}
}
}
}
// Insert or update discussiontools_item_revisions rows, fill in itr_id field values.
foreach ( $threadItemSet->getThreadItems() as $item ) {
$transcl = $item->getTranscludedFrom();
$newOrUpdateRevRow =
[
'itr_itemid_id' => $itemIdsIds[ $item->getId() ],
'itr_revision_id' => $rev->getId(),
'itr_items_id' => $itemsIds[ $item->getId() ],
'itr_parent_id' =>
// This assumes that parent items were processed first
$item->getParent() ? $itemRevisionsIds[ $item->getParent()->getId() ] : null,
'itr_transcludedfrom' =>
$transcl === false ? null : (
$transcl === true ? 0 :
$this->pageStore->getPageByText( $transcl )->getId()
),
'itr_level' => $item->getLevel(),
] +
( $item instanceof HeadingItem ? [
'itr_headinglevel' => $item->isPlaceholderHeading() ? null : $item->getHeadingLevel(),
] : [] );
$itemRevisionsId = $dbw->newSelectQueryBuilder()
->from( 'discussiontools_item_revisions' )
->field( 'itr_id' )
->where( [
'itr_itemid_id' => $itemIdsIds[ $item->getId() ],
'itr_items_id' => $itemsIds[ $item->getId() ],
'itr_revision_id' => $rev->getId(),
] )
->caller( $method )
->fetchField();
if ( $itemRevisionsId === false ) {
$itemRevisionsUpdateId = null;
if ( isset( $revUpdateRows[ $itemsIds[ $item->getId() ] ] ) ) {
$itemRevisionsUpdateId = $dbw->newSelectQueryBuilder()
->from( 'discussiontools_item_revisions' )
->field( 'itr_id' )
->where( [
'itr_revision_id' => $revUpdateRows[ $itemsIds[ $item->getId() ] ],
// We only keep up to 2 discussiontools_item_revisions rows with the same
// (itr_itemid_id, itr_items_id) pair, for the oldest and newest revision known.
// Here we find any rows we don't want to keep and re-use them.
'itr_itemid_id' => $itemIdsIds[ $item->getId() ],
'itr_items_id' => $itemsIds[ $item->getId() ],
] )
->caller( $method )
->fetchField();
// The row to re-use may not be found if it has a different itr_itemid_id than the row
// we want to add.
}
if ( $itemRevisionsUpdateId ) {
$dbw->update(
'discussiontools_item_revisions',
$newOrUpdateRevRow,
[ 'itr_id' => $itemRevisionsUpdateId ],
$method
);
$itemRevisionsId = $itemRevisionsUpdateId;
} else {
$dbw->insert(
'discussiontools_item_revisions',
$newOrUpdateRevRow,
$method
);
$itemRevisionsId = $dbw->insertId();
}
$didInsert = true;
}
$itemRevisionsIds[ $item->getId() ] = $itemRevisionsId;
}
}, $dbw::ATOMIC_CANCELABLE );
return $didInsert;
}
}