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[mediawiki.git] / includes / api / ApiQueryBase.php

<?php
/**
 *
 *
 * Created on Sep 7, 2006
 *
 * Copyright © 2006 Yuri Astrakhan "<Firstname><Lastname>@gmail.com"
 *
 * 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
 */

/**
 * This is a base class for all Query modules.
 * It provides some common functionality such as constructing various SQL
 * queries.
 *
 * @ingroup API
 */
abstract class ApiQueryBase extends ApiBase {

        private $mQueryModule, $mDb, $tables, $where, $fields, $options, $join_conds;

        /**
         * @param $query ApiBase
         * @param $moduleName string
         * @param $paramPrefix string
         */
        public function __construct( ApiBase $query, $moduleName, $paramPrefix = '' ) {
                parent::__construct( $query->getMain(), $moduleName, $paramPrefix );
                $this->mQueryModule = $query;
                $this->mDb = null;
                $this->resetQueryParams();
        }

        /**
         * Get the cache mode for the data generated by this module. Override
         * this in the module subclass. For possible return values and other
         * details about cache modes, see ApiMain::setCacheMode()
         *
         * Public caching will only be allowed if *all* the modules that supply
         * data for a given request return a cache mode of public.
         *
         * @param $params
         * @return string
         */
        public function getCacheMode( $params ) {
                return 'private';
        }

        /**
         * Blank the internal arrays with query parameters
         */
        protected function resetQueryParams() {
                $this->tables = array();
                $this->where = array();
                $this->fields = array();
                $this->options = array();
                $this->join_conds = array();
        }

        /**
         * Add a set of tables to the internal array
         * @param $tables mixed Table name or array of table names
         * @param $alias mixed Table alias, or null for no alias. Cannot be
         *  used with multiple tables
         */
        protected function addTables( $tables, $alias = null ) {
                if ( is_array( $tables ) ) {
                        if ( !is_null( $alias ) ) {
                                ApiBase::dieDebug( __METHOD__, 'Multiple table aliases not supported' );
                        }
                        $this->tables = array_merge( $this->tables, $tables );
                } else {
                        if ( !is_null( $alias ) ) {
                                $this->tables[$alias] = $tables;
                        } else {
                                $this->tables[] = $tables;
                        }
                }
        }

        /**
         * Add a set of JOIN conditions to the internal array
         *
         * JOIN conditions are formatted as array( tablename => array(jointype,
         * conditions) e.g. array('page' => array('LEFT JOIN',
         * 'page_id=rev_page')) . conditions may be a string or an
         * addWhere()-style array
         * @param $join_conds array JOIN conditions
         */
        protected function addJoinConds( $join_conds ) {
                if ( !is_array( $join_conds ) ) {
                        ApiBase::dieDebug( __METHOD__, 'Join conditions have to be arrays' );
                }
                $this->join_conds = array_merge( $this->join_conds, $join_conds );
        }

        /**
         * Add a set of fields to select to the internal array
         * @param array|string $value Field name or array of field names
         */
        protected function addFields( $value ) {
                if ( is_array( $value ) ) {
                        $this->fields = array_merge( $this->fields, $value );
                } else {
                        $this->fields[] = $value;
                }
        }

        /**
         * Same as addFields(), but add the fields only if a condition is met
         * @param array|string $value See addFields()
         * @param bool $condition If false, do nothing
         * @return bool $condition
         */
        protected function addFieldsIf( $value, $condition ) {
                if ( $condition ) {
                        $this->addFields( $value );

                        return true;
                }

                return false;
        }

        /**
         * Add a set of WHERE clauses to the internal array.
         * Clauses can be formatted as 'foo=bar' or array('foo' => 'bar'),
         * the latter only works if the value is a constant (i.e. not another field)
         *
         * If $value is an empty array, this function does nothing.
         *
         * For example, array('foo=bar', 'baz' => 3, 'bla' => 'foo') translates
         * to "foo=bar AND baz='3' AND bla='foo'"
         * @param $value mixed String or array
         */
        protected function addWhere( $value ) {
                if ( is_array( $value ) ) {
                        // Sanity check: don't insert empty arrays,
                        // Database::makeList() chokes on them
                        if ( count( $value ) ) {
                                $this->where = array_merge( $this->where, $value );
                        }
                } else {
                        $this->where[] = $value;
                }
        }

        /**
         * Same as addWhere(), but add the WHERE clauses only if a condition is met
         * @param $value mixed See addWhere()
         * @param bool $condition If false, do nothing
         * @return bool $condition
         */
        protected function addWhereIf( $value, $condition ) {
                if ( $condition ) {
                        $this->addWhere( $value );

                        return true;
                }

                return false;
        }

        /**
         * Equivalent to addWhere(array($field => $value))
         * @param string $field Field name
         * @param string $value Value; ignored if null or empty array;
         */
        protected function addWhereFld( $field, $value ) {
                // Use count() to its full documented capabilities to simultaneously
                // test for null, empty array or empty countable object
                if ( count( $value ) ) {
                        $this->where[$field] = $value;
                }
        }

        /**
         * Add a WHERE clause corresponding to a range, and an ORDER BY
         * clause to sort in the right direction
         * @param string $field Field name
         * @param string $dir If 'newer', sort in ascending order, otherwise
         *  sort in descending order
         * @param string $start Value to start the list at. If $dir == 'newer'
         *  this is the lower boundary, otherwise it's the upper boundary
         * @param string $end Value to end the list at. If $dir == 'newer' this
         *  is the upper boundary, otherwise it's the lower boundary
         * @param bool $sort If false, don't add an ORDER BY clause
         */
        protected function addWhereRange( $field, $dir, $start, $end, $sort = true ) {
                $isDirNewer = ( $dir === 'newer' );
                $after = ( $isDirNewer ? '>=' : '<=' );
                $before = ( $isDirNewer ? '<=' : '>=' );
                $db = $this->getDB();

                if ( !is_null( $start ) ) {
                        $this->addWhere( $field . $after . $db->addQuotes( $start ) );
                }

                if ( !is_null( $end ) ) {
                        $this->addWhere( $field . $before . $db->addQuotes( $end ) );
                }

                if ( $sort ) {
                        $order = $field . ( $isDirNewer ? '' : ' DESC' );
                        // Append ORDER BY
                        $optionOrderBy = isset( $this->options['ORDER BY'] )
                                ? (array)$this->options['ORDER BY']
                                : array();
                        $optionOrderBy[] = $order;
                        $this->addOption( 'ORDER BY', $optionOrderBy );
                }
        }

        /**
         * Add a WHERE clause corresponding to a range, similar to addWhereRange,
         * but converts $start and $end to database timestamps.
         * @see addWhereRange
         * @param $field
         * @param $dir
         * @param $start
         * @param $end
         * @param $sort bool
         */
        protected function addTimestampWhereRange( $field, $dir, $start, $end, $sort = true ) {
                $db = $this->getDb();
                $this->addWhereRange( $field, $dir,
                        $db->timestampOrNull( $start ), $db->timestampOrNull( $end ), $sort );
        }

        /**
         * Add an option such as LIMIT or USE INDEX. If an option was set
         * before, the old value will be overwritten
         * @param string $name Option name
         * @param string $value Option value
         */
        protected function addOption( $name, $value = null ) {
                if ( is_null( $value ) ) {
                        $this->options[] = $name;
                } else {
                        $this->options[$name] = $value;
                }
        }

        /**
         * Execute a SELECT query based on the values in the internal arrays
         * @param string $method Function the query should be attributed to.
         *  You should usually use __METHOD__ here
         * @param array $extraQuery Query data to add but not store in the object
         *  Format is array(
         *    'tables' => ...,
         *    'fields' => ...,
         *    'where' => ...,
         *    'options' => ...,
         *    'join_conds' => ...
         *  )
         * @return ResultWrapper
         */
        protected function select( $method, $extraQuery = array() ) {

                $tables = array_merge(
                        $this->tables,
                        isset( $extraQuery['tables'] ) ? (array)$extraQuery['tables'] : array()
                );
                $fields = array_merge(
                        $this->fields,
                        isset( $extraQuery['fields'] ) ? (array)$extraQuery['fields'] : array()
                );
                $where = array_merge(
                        $this->where,
                        isset( $extraQuery['where'] ) ? (array)$extraQuery['where'] : array()
                );
                $options = array_merge(
                        $this->options,
                        isset( $extraQuery['options'] ) ? (array)$extraQuery['options'] : array()
                );
                $join_conds = array_merge(
                        $this->join_conds,
                        isset( $extraQuery['join_conds'] ) ? (array)$extraQuery['join_conds'] : array()
                );

                // getDB has its own profileDBIn/Out calls
                $db = $this->getDB();

                $this->profileDBIn();
                $res = $db->select( $tables, $fields, $where, $method, $options, $join_conds );
                $this->profileDBOut();

                return $res;
        }

        /**
         * Estimate the row count for the SELECT query that would be run if we
         * called select() right now, and check if it's acceptable.
         * @return bool true if acceptable, false otherwise
         */
        protected function checkRowCount() {
                $db = $this->getDB();
                $this->profileDBIn();
                $rowcount = $db->estimateRowCount(
                        $this->tables,
                        $this->fields,
                        $this->where,
                        __METHOD__,
                        $this->options
                );
                $this->profileDBOut();

                global $wgAPIMaxDBRows;
                if ( $rowcount > $wgAPIMaxDBRows ) {
                        return false;
                }

                return true;
        }

        /**
         * Add information (title and namespace) about a Title object to a
         * result array
         * @param array $arr Result array à la ApiResult
         * @param $title Title
         * @param string $prefix Module prefix
         */
        public static function addTitleInfo( &$arr, $title, $prefix = '' ) {
                $arr[$prefix . 'ns'] = intval( $title->getNamespace() );
                $arr[$prefix . 'title'] = $title->getPrefixedText();
        }

        /**
         * Override this method to request extra fields from the pageSet
         * using $pageSet->requestField('fieldName')
         * @param $pageSet ApiPageSet
         */
        public function requestExtraData( $pageSet ) {
        }

        /**
         * Get the main Query module
         * @return ApiQuery
         */
        public function getQuery() {
                return $this->mQueryModule;
        }

        /**
         * Add a sub-element under the page element with the given page ID
         * @param int $pageId Page ID
         * @param array $data Data array à la ApiResult
         * @return bool Whether the element fit in the result
         */
        protected function addPageSubItems( $pageId, $data ) {
                $result = $this->getResult();
                $result->setIndexedTagName( $data, $this->getModulePrefix() );

                return $result->addValue( array( 'query', 'pages', intval( $pageId ) ),
                        $this->getModuleName(),
                        $data );
        }

        /**
         * Same as addPageSubItems(), but one element of $data at a time
         * @param int $pageId Page ID
         * @param array $item Data array à la ApiResult
         * @param string $elemname XML element name. If null, getModuleName()
         *  is used
         * @return bool Whether the element fit in the result
         */
        protected function addPageSubItem( $pageId, $item, $elemname = null ) {
                if ( is_null( $elemname ) ) {
                        $elemname = $this->getModulePrefix();
                }
                $result = $this->getResult();
                $fit = $result->addValue( array( 'query', 'pages', $pageId,
                        $this->getModuleName() ), null, $item );
                if ( !$fit ) {
                        return false;
                }
                $result->setIndexedTagName_internal( array( 'query', 'pages', $pageId,
                        $this->getModuleName() ), $elemname );

                return true;
        }

        /**
         * Set a query-continue value
         * @param string $paramName Parameter name
         * @param string $paramValue Parameter value
         */
        protected function setContinueEnumParameter( $paramName, $paramValue ) {
                $paramName = $this->encodeParamName( $paramName );
                $msg = array( $paramName => $paramValue );
                $result = $this->getResult();
                $result->disableSizeCheck();
                $result->addValue( 'query-continue', $this->getModuleName(), $msg, ApiResult::ADD_ON_TOP );
                $result->enableSizeCheck();
        }

        /**
         * Get the Query database connection (read-only)
         * @return DatabaseBase
         */
        protected function getDB() {
                if ( is_null( $this->mDb ) ) {
                        $this->mDb = $this->getQuery()->getDB();
                }

                return $this->mDb;
        }

        /**
         * Selects the query database connection with the given name.
         * See ApiQuery::getNamedDB() for more information
         * @param string $name Name to assign to the database connection
         * @param int $db One of the DB_* constants
         * @param array $groups Query groups
         * @return DatabaseBase
         */
        public function selectNamedDB( $name, $db, $groups ) {
                $this->mDb = $this->getQuery()->getNamedDB( $name, $db, $groups );
        }

        /**
         * Get the PageSet object to work on
         * @return ApiPageSet
         */
        protected function getPageSet() {
                return $this->getQuery()->getPageSet();
        }

        /**
         * Convert a title to a DB key
         * @param string $title Page title with spaces
         * @return string Page title with underscores
         */
        public function titleToKey( $title ) {
                // Don't throw an error if we got an empty string
                if ( trim( $title ) == '' ) {
                        return '';
                }
                $t = Title::newFromText( $title );
                if ( !$t ) {
                        $this->dieUsageMsg( array( 'invalidtitle', $title ) );
                }

                return $t->getPrefixedDBkey();
        }

        /**
         * The inverse of titleToKey()
         * @param string $key Page title with underscores
         * @return string Page title with spaces
         */
        public function keyToTitle( $key ) {
                // Don't throw an error if we got an empty string
                if ( trim( $key ) == '' ) {
                        return '';
                }
                $t = Title::newFromDBkey( $key );
                // This really shouldn't happen but we gotta check anyway
                if ( !$t ) {
                        $this->dieUsageMsg( array( 'invalidtitle', $key ) );
                }

                return $t->getPrefixedText();
        }

        /**
         * An alternative to titleToKey() that doesn't trim trailing spaces
         * @param string $titlePart Title part with spaces
         * @return string Title part with underscores
         */
        public function titlePartToKey( $titlePart ) {
                return substr( $this->titleToKey( $titlePart . 'x' ), 0, -1 );
        }

        /**
         * An alternative to keyToTitle() that doesn't trim trailing spaces
         * @param string $keyPart Key part with spaces
         * @return string Key part with underscores
         */
        public function keyPartToTitle( $keyPart ) {
                return substr( $this->keyToTitle( $keyPart . 'x' ), 0, -1 );
        }

        /**
         * Gets the personalised direction parameter description
         *
         * @param string $p ModulePrefix
         * @param string $extraDirText Any extra text to be appended on the description
         * @return array
         */
        public function getDirectionDescription( $p = '', $extraDirText = '' ) {
                return array(
                        "In which direction to enumerate{$extraDirText}",
                        " newer          - List oldest first. Note: {$p}start has to be before {$p}end.",
                        " older          - List newest first (default). Note: {$p}start has to be later than {$p}end.",
                );
        }

        /**
         * @param $query String
         * @param $protocol String
         * @return null|string
         */
        public function prepareUrlQuerySearchString( $query = null, $protocol = null ) {
                $db = $this->getDb();
                if ( !is_null( $query ) || $query != '' ) {
                        if ( is_null( $protocol ) ) {
                                $protocol = 'http://';
                        }

                        $likeQuery = LinkFilter::makeLikeArray( $query, $protocol );
                        if ( !$likeQuery ) {
                                $this->dieUsage( 'Invalid query', 'bad_query' );
                        }

                        $likeQuery = LinkFilter::keepOneWildcard( $likeQuery );

                        return 'el_index ' . $db->buildLike( $likeQuery );
                } elseif ( !is_null( $protocol ) ) {
                        return 'el_index ' . $db->buildLike( "$protocol", $db->anyString() );
                }

                return null;
        }

        /**
         * Filters hidden users (where the user doesn't have the right to view them)
         * Also adds relevant block information
         *
         * @param bool $showBlockInfo
         * @return void
         */
        public function showHiddenUsersAddBlockInfo( $showBlockInfo ) {
                $userCanViewHiddenUsers = $this->getUser()->isAllowed( 'hideuser' );

                if ( $showBlockInfo || !$userCanViewHiddenUsers ) {
                        $this->addTables( 'ipblocks' );
                        $this->addJoinConds( array(
                                'ipblocks' => array( 'LEFT JOIN', 'ipb_user=user_id' ),
                        ) );

                        $this->addFields( 'ipb_deleted' );

                        if ( $showBlockInfo ) {
                                $this->addFields( array( 'ipb_id', 'ipb_by', 'ipb_by_text', 'ipb_reason', 'ipb_expiry' ) );
                        }

                        // Don't show hidden names
                        if ( !$userCanViewHiddenUsers ) {
                                $this->addWhere( 'ipb_deleted = 0 OR ipb_deleted IS NULL' );
                        }
                }
        }

        /**
         * @param $hash string
         * @return bool
         */
        public function validateSha1Hash( $hash ) {
                return preg_match( '/^[a-f0-9]{40}$/', $hash );
        }

        /**
         * @param $hash string
         * @return bool
         */
        public function validateSha1Base36Hash( $hash ) {
                return preg_match( '/^[a-z0-9]{31}$/', $hash );
        }

        /**
         * @return array
         */
        public function getPossibleErrors() {
                $errors = parent::getPossibleErrors();
                $errors = array_merge( $errors, array(
                        array( 'invalidtitle', 'title' ),
                        array( 'invalidtitle', 'key' ),
                ) );

                return $errors;
        }
}

/**
 * @ingroup API
 */
abstract class ApiQueryGeneratorBase extends ApiQueryBase {

        private $mGeneratorPageSet = null;

        /**
         * Switch this module to generator mode. By default, generator mode is
         * switched off and the module acts like a normal query module.
         * @since 1.21 requires pageset parameter
         * @param $generatorPageSet ApiPageSet object that the module will get
         *        by calling getPageSet() when in generator mode.
         */
        public function setGeneratorMode( ApiPageSet $generatorPageSet ) {
                if ( $generatorPageSet === null ) {
                        ApiBase::dieDebug( __METHOD__, 'Required parameter missing - $generatorPageSet' );
                }
                $this->mGeneratorPageSet = $generatorPageSet;
        }

        /**
         * Get the PageSet object to work on.
         * If this module is generator, the pageSet object is different from other module's
         * @return ApiPageSet
         */
        protected function getPageSet() {
                if ( $this->mGeneratorPageSet !== null ) {
                        return $this->mGeneratorPageSet;
                }

                return parent::getPageSet();
        }

        /**
         * Overrides base class to prepend 'g' to every generator parameter
         * @param string $paramName Parameter name
         * @return string Prefixed parameter name
         */
        public function encodeParamName( $paramName ) {
                if ( $this->mGeneratorPageSet !== null ) {
                        return 'g' . parent::encodeParamName( $paramName );
                } else {
                        return parent::encodeParamName( $paramName );
                }
        }

        /**
         * Overrides base in case of generator & smart continue to
         * notify ApiQueryMain instead of adding them to the result right away.
         * @param string $paramName Parameter name
         * @param string $paramValue Parameter value
         */
        protected function setContinueEnumParameter( $paramName, $paramValue ) {
                // If this is a generator and query->setGeneratorContinue() returns false, treat as before
                if ( $this->mGeneratorPageSet === null
                        || !$this->getQuery()->setGeneratorContinue( $this, $paramName, $paramValue )
                ) {
                        parent::setContinueEnumParameter( $paramName, $paramValue );
                }
        }

        /**
         * Execute this module as a generator
         * @param $resultPageSet ApiPageSet: All output should be appended to
         *  this object
         */
        abstract public function executeGenerator( $resultPageSet );
}