CentralIdLookup: Add @since to factoryNonLocal()

[mediawiki.git] / includes / ActorMigration.php

<?php
/**
 * Methods to help with the actor table migration
 *
 * 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
 */

use MediaWiki\MediaWikiServices;
use MediaWiki\User\UserIdentity;
use Wikimedia\Rdbms\IDatabase;

/**
 * This class handles the logic for the actor table migration and should
 * always be used in lieu of directly accessing database tables.
 *
 * This is not intended to be a long-term part of MediaWiki; it will be
 * deprecated and removed once actor migration is complete.
 *
 * @since 1.31
 * @since 1.34 Use with 'ar_user', 'img_user', 'oi_user', 'fa_user',
 *  'rc_user', 'log_user', and 'ipb_by' is deprecated. Callers should
 *  reference the corresponding actor fields directly.
 */
class ActorMigration {

        /**
         * Constant for extensions to feature-test whether $wgActorTableSchemaMigrationStage
         * (in MW <1.34) expects MIGRATION_* or SCHEMA_COMPAT_*
         */
        public const MIGRATION_STAGE_SCHEMA_COMPAT = 1;

        /**
         * Define fields that use temporary tables for transitional purposes
         * @var array Keys are '$key', values are arrays with four fields:
         *  - table: Temporary table name
         *  - pk: Temporary table column referring to the main table's primary key
         *  - field: Temporary table column referring actor.actor_id
         *  - joinPK: Main table's primary key
         */
        private static $tempTables = [
                'rev_user' => [
                        'table' => 'revision_actor_temp',
                        'pk' => 'revactor_rev',
                        'field' => 'revactor_actor',
                        'joinPK' => 'rev_id',
                        'extra' => [
                                'revactor_timestamp' => 'rev_timestamp',
                                'revactor_page' => 'rev_page',
                        ],
                ],
        ];

        /**
         * Fields that formerly used $tempTables
         * @var array Key is '$key', value is the MediaWiki version in which it was
         *  removed from $tempTables.
         */
        private static $formerTempTables = [];

        /**
         * Define fields that are deprecated for use with this class.
         * @var (string|null)[] Keys are '$key', value is null for soft deprecation
         *  or a string naming the deprecated version for hard deprecation.
         */
        private static $deprecated = [
                'ar_user' => null, // 1.34
                'img_user' => null, // 1.34
                'oi_user' => null, // 1.34
                'fa_user' => null, // 1.34
                'rc_user' => null, // 1.34
                'log_user' => null, // 1.34
                'ipb_by' => null, // 1.34
        ];

        /**
         * Define fields that are removed for use with this class.
         * @var string[] Keys are '$key', value is the MediaWiki version in which
         *  use was removed.
         */
        private static $removed = [];

        /**
         * Define fields that use non-standard mapping
         * @var array Keys are the user id column name, values are arrays with two
         *  elements (the user text column name and the actor id column name)
         */
        private static $specialFields = [
                'ipb_by' => [ 'ipb_by_text', 'ipb_by_actor' ],
        ];

        /** @var array Cache for `self::getJoin()` */
        private $joinCache = [];

        /** @var int Combination of SCHEMA_COMPAT_* constants */
        private $stage;

        /**
         * @internal
         * @param int $stage
         */
        public function __construct( $stage ) {
                if ( ( $stage & SCHEMA_COMPAT_WRITE_BOTH ) === 0 ) {
                        throw new InvalidArgumentException( '$stage must include a write mode' );
                }
                if ( ( $stage & SCHEMA_COMPAT_READ_BOTH ) === 0 ) {
                        throw new InvalidArgumentException( '$stage must include a read mode' );
                }
                if ( ( $stage & SCHEMA_COMPAT_READ_BOTH ) === SCHEMA_COMPAT_READ_BOTH ) {
                        throw new InvalidArgumentException( 'Cannot read both schemas' );
                }
                if ( ( $stage & SCHEMA_COMPAT_READ_OLD ) && !( $stage & SCHEMA_COMPAT_WRITE_OLD ) ) {
                        throw new InvalidArgumentException( 'Cannot read the old schema without also writing it' );
                }
                if ( ( $stage & SCHEMA_COMPAT_READ_NEW ) && !( $stage & SCHEMA_COMPAT_WRITE_NEW ) ) {
                        throw new InvalidArgumentException( 'Cannot read the new schema without also writing it' );
                }

                $this->stage = $stage;
        }

        /**
         * Static constructor
         * @return ActorMigration
         */
        public static function newMigration() {
                return MediaWikiServices::getInstance()->getActorMigration();
        }

        /**
         * Issue deprecation warning/error as appropriate.
         * @param string $key
         */
        private static function checkDeprecation( $key ) {
                if ( isset( self::$removed[$key] ) ) {
                        throw new InvalidArgumentException(
                                "Use of " . static::class . " for '$key' was removed in MediaWiki " . self::$removed[$key]
                        );
                }
                if ( !empty( self::$deprecated[$key] ) ) {
                        wfDeprecated( static::class . " for '$key'", self::$deprecated[$key], false, 3 );
                }
        }

        /**
         * Return an SQL condition to test if a user field is anonymous
         * @param string $field Field name or SQL fragment
         * @return string
         */
        public function isAnon( $field ) {
                return ( $this->stage & SCHEMA_COMPAT_READ_NEW ) ? "$field IS NULL" : "$field = 0";
        }

        /**
         * Return an SQL condition to test if a user field is non-anonymous
         * @param string $field Field name or SQL fragment
         * @return string
         */
        public function isNotAnon( $field ) {
                return ( $this->stage & SCHEMA_COMPAT_READ_NEW ) ? "$field IS NOT NULL" : "$field != 0";
        }

        /**
         * @param string $key A key such as "rev_user" identifying the actor
         *  field being fetched.
         * @return string[] [ $text, $actor ]
         */
        private static function getFieldNames( $key ) {
                return self::$specialFields[$key] ?? [ $key . '_text', substr( $key, 0, -5 ) . '_actor' ];
        }

        /**
         * Get SELECT fields and joins for the actor key
         *
         * @param string $key A key such as "rev_user" identifying the actor
         *  field being fetched.
         * @return array[] With three keys:
         *   - tables: (string[]) to include in the `$table` to `IDatabase->select()`
         *   - fields: (string[]) to include in the `$vars` to `IDatabase->select()`
         *   - joins: (array) to include in the `$join_conds` to `IDatabase->select()`
         *  All tables, fields, and joins are aliased, so `+` is safe to use.
         * @phan-return array{tables:string[],fields:string[],joins:array}
         */
        public function getJoin( $key ) {
                self::checkDeprecation( $key );

                if ( !isset( $this->joinCache[$key] ) ) {
                        $tables = [];
                        $fields = [];
                        $joins = [];

                        list( $text, $actor ) = self::getFieldNames( $key );

                        if ( $this->stage & SCHEMA_COMPAT_READ_OLD ) {
                                $fields[$key] = $key;
                                $fields[$text] = $text;
                                $fields[$actor] = 'NULL';
                        } else {
                                if ( isset( self::$tempTables[$key] ) ) {
                                        $t = self::$tempTables[$key];
                                        $alias = "temp_$key";
                                        $tables[$alias] = $t['table'];
                                        $joins[$alias] = [ 'JOIN', "{$alias}.{$t['pk']} = {$t['joinPK']}" ];
                                        $joinField = "{$alias}.{$t['field']}";
                                } else {
                                        $joinField = $actor;
                                }

                                $alias = "actor_$key";
                                $tables[$alias] = 'actor';
                                $joins[$alias] = [ 'JOIN', "{$alias}.actor_id = {$joinField}" ];

                                $fields[$key] = "{$alias}.actor_user";
                                $fields[$text] = "{$alias}.actor_name";
                                $fields[$actor] = $joinField;
                        }

                        $this->joinCache[$key] = [
                                'tables' => $tables,
                                'fields' => $fields,
                                'joins' => $joins,
                        ];
                }

                return $this->joinCache[$key];
        }

        /**
         * Get UPDATE fields for the actor
         *
         * @param IDatabase $dbw Database to use for creating an actor ID, if necessary
         * @param string $key A key such as "rev_user" identifying the actor
         *  field being fetched.
         * @param UserIdentity $user User to set in the update
         * @return array to merge into `$values` to `IDatabase->update()` or `$a` to `IDatabase->insert()`
         */
        public function getInsertValues( IDatabase $dbw, $key, UserIdentity $user ) {
                self::checkDeprecation( $key );

                if ( isset( self::$tempTables[$key] ) ) {
                        throw new InvalidArgumentException( "Must use getInsertValuesWithTempTable() for $key" );
                }

                list( $text, $actor ) = self::getFieldNames( $key );
                $ret = [];
                if ( $this->stage & SCHEMA_COMPAT_WRITE_OLD ) {
                        $ret[$key] = $user->getId();
                        $ret[$text] = $user->getName();
                }
                if ( $this->stage & SCHEMA_COMPAT_WRITE_NEW ) {
                        // We need to be able to assign an actor ID if none exists
                        if ( !$user instanceof User && !$user->getActorId() ) {
                                $user = User::newFromAnyId( $user->getId(), $user->getName(), null );
                        }
                        $ret[$actor] = $user->getActorId( $dbw );
                }
                return $ret;
        }

        /**
         * Get UPDATE fields for the actor
         *
         * @param IDatabase $dbw Database to use for creating an actor ID, if necessary
         * @param string $key A key such as "rev_user" identifying the actor
         *  field being fetched.
         * @param UserIdentity $user User to set in the update
         * @return array with two values:
         *  - array to merge into `$values` to `IDatabase->update()` or `$a` to `IDatabase->insert()`
         *  - callback to call with the primary key for the main table insert
         *    and extra fields needed for the temp table.
         */
        public function getInsertValuesWithTempTable( IDatabase $dbw, $key, UserIdentity $user ) {
                self::checkDeprecation( $key );

                if ( isset( self::$formerTempTables[$key] ) ) {
                        wfDeprecated( __METHOD__ . " for $key", self::$formerTempTables[$key] );
                } elseif ( !isset( self::$tempTables[$key] ) ) {
                        throw new InvalidArgumentException( "Must use getInsertValues() for $key" );
                }

                list( $text, $actor ) = self::getFieldNames( $key );
                $ret = [];
                $callback = null;
                if ( $this->stage & SCHEMA_COMPAT_WRITE_OLD ) {
                        $ret[$key] = $user->getId();
                        $ret[$text] = $user->getName();
                }
                if ( $this->stage & SCHEMA_COMPAT_WRITE_NEW ) {
                        // We need to be able to assign an actor ID if none exists
                        if ( !$user instanceof User && !$user->getActorId() ) {
                                $user = User::newFromAnyId( $user->getId(), $user->getName(), null );
                        }
                        $id = $user->getActorId( $dbw );

                        if ( isset( self::$tempTables[$key] ) ) {
                                $func = __METHOD__;
                                $callback = function ( $pk, array $extra ) use ( $dbw, $key, $id, $func ) {
                                        $t = self::$tempTables[$key];
                                        $set = [ $t['field'] => $id ];
                                        foreach ( $t['extra'] as $to => $from ) {
                                                if ( !array_key_exists( $from, $extra ) ) {
                                                        throw new InvalidArgumentException( "$func callback: \$extra[$from] is not provided" );
                                                }
                                                $set[$to] = $extra[$from];
                                        }
                                        $dbw->upsert(
                                                $t['table'],
                                                [ $t['pk'] => $pk ] + $set,
                                                [ [ $t['pk'] ] ],
                                                $set,
                                                $func
                                        );
                                };
                        } else {
                                $ret[$actor] = $id;
                                $callback = function ( $pk, array $extra ) {
                                };
                        }
                } elseif ( isset( self::$tempTables[$key] ) ) {
                        $func = __METHOD__;
                        $callback = function ( $pk, array $extra ) use ( $key, $func ) {
                                $t = self::$tempTables[$key];
                                foreach ( $t['extra'] as $to => $from ) {
                                        if ( !array_key_exists( $from, $extra ) ) {
                                                throw new InvalidArgumentException( "$func callback: \$extra[$from] is not provided" );
                                        }
                                }
                        };
                } else {
                        $callback = function ( $pk, array $extra ) {
                        };
                }
                return [ $ret, $callback ];
        }

        /**
         * Get WHERE condition for the actor
         *
         * @param IDatabase $db Database to use for quoting and list-making
         * @param string $key A key such as "rev_user" identifying the actor
         *  field being fetched.
         * @param UserIdentity|UserIdentity[]|null|false $users Users to test for.
         *  Passing null, false, or the empty array will return 'conds' that never match,
         *  and an empty array for 'orconds'.
         * @param bool $useId If false, don't try to query by the user ID.
         *  Intended for use with rc_user since it has an index on
         *  (rc_user_text,rc_timestamp) but not (rc_user,rc_timestamp).
         * @return array With three keys:
         *   - tables: (string[]) to include in the `$table` to `IDatabase->select()`
         *   - conds: (string) to include in the `$cond` to `IDatabase->select()`
         *   - orconds: (array[]) array of alternatives in case a union of multiple
         *     queries would be more efficient than a query with OR. May have keys
         *     'actor', 'userid', 'username'.
         *     Since 1.32, this is guaranteed to contain just one alternative if
         *     $users contains a single user.
         *   - joins: (array) to include in the `$join_conds` to `IDatabase->select()`
         *  All tables and joins are aliased, so `+` is safe to use.
         */
        public function getWhere( IDatabase $db, $key, $users, $useId = true ) {
                self::checkDeprecation( $key );

                $tables = [];
                $conds = [];
                $joins = [];

                if ( $users instanceof UserIdentity ) {
                        $users = [ $users ];
                } elseif ( $users === null || $users === false ) {
                        // DWIM
                        $users = [];
                } elseif ( !is_array( $users ) ) {
                        $what = is_object( $users ) ? get_class( $users ) : gettype( $users );
                        throw new InvalidArgumentException(
                                __METHOD__ . ": Value for \$users must be a UserIdentity or array, got $what"
                        );
                }

                // Get information about all the passed users
                $ids = [];
                $names = [];
                $actors = [];
                foreach ( $users as $user ) {
                        if ( $useId && $user->getId() ) {
                                $ids[] = $user->getId();
                        } else {
                                $names[] = $user->getName();
                        }
                        $actorId = $user->getActorId();
                        if ( $actorId ) {
                                $actors[] = $actorId;
                        }
                }

                list( $text, $actor ) = self::getFieldNames( $key );

                // Combine data into conditions to be ORed together
                if ( $this->stage & SCHEMA_COMPAT_READ_NEW ) {
                        if ( $actors ) {
                                if ( isset( self::$tempTables[$key] ) ) {
                                        $t = self::$tempTables[$key];
                                        $alias = "temp_$key";
                                        $tables[$alias] = $t['table'];
                                        $joins[$alias] = [ 'JOIN', "{$alias}.{$t['pk']} = {$t['joinPK']}" ];
                                        $joinField = "{$alias}.{$t['field']}";
                                } else {
                                        $joinField = $actor;
                                }
                                $conds['actor'] = $db->makeList( [ $joinField => $actors ], IDatabase::LIST_AND );
                        }
                } else {
                        if ( $ids ) {
                                $conds['userid'] = $db->makeList( [ $key => $ids ], IDatabase::LIST_AND );
                        }
                        if ( $names ) {
                                $conds['username'] = $db->makeList( [ $text => $names ], IDatabase::LIST_AND );
                        }
                }

                return [
                        'tables' => $tables,
                        'conds' => $conds ? $db->makeList( array_values( $conds ), IDatabase::LIST_OR ) : '1=0',
                        'orconds' => $conds,
                        'joins' => $joins,
                ];
        }

}