Per Nikerabbit, follow-up to r64522: use __METHOD__

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

<?php

/**
 * Created on Sep 24, 2006
 *
 * API for MediaWiki 1.8+
 *
 * 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.,
 * 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 * http://www.gnu.org/copyleft/gpl.html
 */

if ( !defined( 'MEDIAWIKI' ) ) {
        // Eclipse helper - will be ignored in production
        require_once( 'ApiQueryBase.php' );
}

/**
 * This class contains a list of pages that the client has requested.
 * Initially, when the client passes in titles=, pageids=, or revisions=
 * parameter, an instance of the ApiPageSet class will normalize titles,
 * determine if the pages/revisions exist, and prefetch any additional page
 * data requested.
 *
 * When a generator is used, the result of the generator will become the input
 * for the second instance of this class, and all subsequent actions will use
 * the second instance for all their work.
 *
 * @ingroup API
 */
class ApiPageSet extends ApiQueryBase {

        private $mAllPages; // [ns][dbkey] => page_id or negative when missing
        private $mTitles, $mGoodTitles, $mMissingTitles, $mInvalidTitles;
        private $mMissingPageIDs, $mRedirectTitles;
        private $mNormalizedTitles, $mInterwikiTitles;
        private $mResolveRedirects, $mPendingRedirectIDs;
        private $mGoodRevIDs, $mMissingRevIDs;
        private $mFakePageId;

        private $mRequestedPageFields;

        /**
         * Constructor
         * @param $query ApiQuery
         * @param $resolveRedirects bool Whether redirects should be resolved
         */
        public function __construct( $query, $resolveRedirects = false ) {
                parent::__construct( $query, 'query' );

                $this->mAllPages = array();
                $this->mTitles = array();
                $this->mGoodTitles = array();
                $this->mMissingTitles = array();
                $this->mInvalidTitles = array();
                $this->mMissingPageIDs = array();
                $this->mRedirectTitles = array();
                $this->mNormalizedTitles = array();
                $this->mInterwikiTitles = array();
                $this->mGoodRevIDs = array();
                $this->mMissingRevIDs = array();

                $this->mRequestedPageFields = array();
                $this->mResolveRedirects = $resolveRedirects;
                if ( $resolveRedirects ) {
                        $this->mPendingRedirectIDs = array();
                }

                $this->mFakePageId = -1;
        }

        /**
         * Check whether this PageSet is resolving redirects
         * @return bool
         */
        public function isResolvingRedirects() {
                return $this->mResolveRedirects;
        }

        /**
         * Request an additional field from the page table. Must be called
         * before execute()
         * @param $fieldName string Field name
         */
        public function requestField( $fieldName ) {
                $this->mRequestedPageFields[$fieldName] = null;
        }

        /**
         * Get the value of a custom field previously requested through
         * requestField()
         * @param $fieldName string Field name
         * @return mixed Field value
         */
        public function getCustomField( $fieldName ) {
                return $this->mRequestedPageFields[$fieldName];
        }

        /**
         * Get the fields that have to be queried from the page table:
         * the ones requested through requestField() and a few basic ones
         * we always need
         * @return array of field names
         */
        public function getPageTableFields() {
                // Ensure we get minimum required fields
                // DON'T change this order
                $pageFlds = array(
                        'page_namespace' => null,
                        'page_title' => null,
                        'page_id' => null,
                );

                if ( $this->mResolveRedirects ) {
                        $pageFlds['page_is_redirect'] = null;
                }

                // only store non-default fields
                $this->mRequestedPageFields = array_diff_key( $this->mRequestedPageFields, $pageFlds );

                $pageFlds = array_merge( $pageFlds, $this->mRequestedPageFields );
                return array_keys( $pageFlds );
        }

        /**
         * Returns an array [ns][dbkey] => page_id for all requested titles.
         * page_id is a unique negative number in case title was not found.
         * Invalid titles will also have negative page IDs and will be in namespace 0
         * @return array
         */
        public function getAllTitlesByNamespace() {
                return $this->mAllPages;
        }

        /**
         * All Title objects provided.
         * @return array of Title objects
         */
        public function getTitles() {
                return $this->mTitles;
        }

        /**
         * Returns the number of unique pages (not revisions) in the set.
         * @return int
         */
        public function getTitleCount() {
                return count( $this->mTitles );
        }

        /**
         * Title objects that were found in the database.
         * @return array page_id (int) => Title (obj)
         */
        public function getGoodTitles() {
                return $this->mGoodTitles;
        }

        /**
         * Returns the number of found unique pages (not revisions) in the set.
         * @return int
         */
        public function getGoodTitleCount() {
                return count( $this->mGoodTitles );
        }

        /**
         * Title objects that were NOT found in the database.
         * The array's index will be negative for each item
         * @return array of Title objects
         */
        public function getMissingTitles() {
                return $this->mMissingTitles;
        }

        /**
         * Titles that were deemed invalid by Title::newFromText()
         * The array's index will be unique and negative for each item
         * @return array of strings (not Title objects)
         */
        public function getInvalidTitles() {
                return $this->mInvalidTitles;
        }

        /**
         * Page IDs that were not found in the database
         * @return array of page IDs
         */
        public function getMissingPageIDs() {
                return $this->mMissingPageIDs;
        }

        /**
         * Get a list of redirect resolutions - maps a title to its redirect
         * target.
         * @return array prefixed_title (string) => prefixed_title (string)
         */
        public function getRedirectTitles() {
                return $this->mRedirectTitles;
        }

        /**
         * Get a list of title normalizations - maps a title to its normalized
         * version.
         * @return array raw_prefixed_title (string) => prefixed_title (string)
         */
        public function getNormalizedTitles() {
                return $this->mNormalizedTitles;
        }

        /**
         * Get a list of interwiki titles - maps a title to its interwiki
         * prefix.
         * @return array raw_prefixed_title (string) => interwiki_prefix (string)
         */
        public function getInterwikiTitles() {
                return $this->mInterwikiTitles;
        }

        /**
         * Get the list of revision IDs (requested with the revids= parameter)
         * @return array revID (int) => pageID (int)
         */
        public function getRevisionIDs() {
                return $this->mGoodRevIDs;
        }

        /**
         * Revision IDs that were not found in the database
         * @return array of revision IDs
         */
        public function getMissingRevisionIDs() {
                return $this->mMissingRevIDs;
        }

        /**
         * Returns the number of revisions (requested with revids= parameter)\
         * @return int
         */
        public function getRevisionCount() {
                return count( $this->getRevisionIDs() );
        }

        /**
         * Populate the PageSet from the request parameters.
         */
        public function execute() {
                $this->profileIn();
                $params = $this->extractRequestParams();

                // Only one of the titles/pageids/revids is allowed at the same time
                $dataSource = null;
                if ( isset( $params['titles'] ) ) {
                        $dataSource = 'titles';
                }
                if ( isset( $params['pageids'] ) ) {
                        if ( isset( $dataSource ) ) {
                                $this->dieUsage( "Cannot use 'pageids' at the same time as '$dataSource'", 'multisource' );
                        }
                        $dataSource = 'pageids';
                }
                if ( isset( $params['revids'] ) ) {
                        if ( isset( $dataSource ) ) {
                                $this->dieUsage( "Cannot use 'revids' at the same time as '$dataSource'", 'multisource' );
                        }
                        $dataSource = 'revids';
                }

                switch ( $dataSource ) {
                        case 'titles':
                                $this->initFromTitles( $params['titles'] );
                                break;
                        case 'pageids':
                                $this->initFromPageIds( $params['pageids'] );
                                break;
                        case 'revids':
                                if ( $this->mResolveRedirects ) {
                                        $this->setWarning( 'Redirect resolution cannot be used together with the revids= parameter. ' .
                                        'Any redirects the revids= point to have not been resolved.' );
                                }
                                $this->mResolveRedirects = false;
                                $this->initFromRevIDs( $params['revids'] );
                                break;
                        default:
                                // Do nothing - some queries do not need any of the data sources.
                                break;
                }
                $this->profileOut();
        }

        /**
         * Populate this PageSet from a list of Titles
         * @param $titles array of Title objects
         */
        public function populateFromTitles( $titles ) {
                $this->profileIn();
                $this->initFromTitles( $titles );
                $this->profileOut();
        }

        /**
         * Populate this PageSet from a list of page IDs
         * @param $pageIDs array of page IDs
         */
        public function populateFromPageIDs( $pageIDs ) {
                $this->profileIn();
                $this->initFromPageIds( $pageIDs );
                $this->profileOut();
        }

        /**
         * Populate this PageSet from a rowset returned from the database
         * @param $db Database object
         * @param $queryResult Query result object
         */
        public function populateFromQueryResult( $db, $queryResult ) {
                $this->profileIn();
                $this->initFromQueryResult( $db, $queryResult );
                $this->profileOut();
        }

        /**
         * Populate this PageSet from a list of revision IDs
         * @param $revIDs array of revision IDs
         */
        public function populateFromRevisionIDs( $revIDs ) {
                $this->profileIn();
                $this->initFromRevIDs( $revIDs );
                $this->profileOut();
        }

        /**
         * Extract all requested fields from the row received from the database
         * @param $row Result row
         */
        public function processDbRow( $row ) {
                // Store Title object in various data structures
                $title = Title::makeTitle( $row->page_namespace, $row->page_title );

                $pageId = intval( $row->page_id );
                $this->mAllPages[$row->page_namespace][$row->page_title] = $pageId;
                $this->mTitles[] = $title;

                if ( $this->mResolveRedirects && $row->page_is_redirect == '1' ) {
                        $this->mPendingRedirectIDs[$pageId] = $title;
                } else {
                        $this->mGoodTitles[$pageId] = $title;
                }

                foreach ( $this->mRequestedPageFields as $fieldName => &$fieldValues ) {
                        $fieldValues[$pageId] = $row-> $fieldName;
                }
        }

        /**
         * Resolve redirects, if applicable
         */
        public function finishPageSetGeneration() {
                $this->profileIn();
                $this->resolvePendingRedirects();
                $this->profileOut();
        }

        /**
         * This method populates internal variables with page information
         * based on the given array of title strings.
         *
         * Steps:
         * #1 For each title, get data from `page` table
         * #2 If page was not found in the DB, store it as missing
         *
         * Additionally, when resolving redirects:
         * #3 If no more redirects left, stop.
         * #4 For each redirect, get its target from the `redirect` table.
         * #5 Substitute the original LinkBatch object with the new list
         * #6 Repeat from step #1
         *
         * @param $titles array of Title objects or strings
         */
        private function initFromTitles( $titles ) {
                // Get validated and normalized title objects
                $linkBatch = $this->processTitlesArray( $titles );
                if ( $linkBatch->isEmpty() ) {
                        return;
                }

                $db = $this->getDB();
                $set = $linkBatch->constructSet( 'page', $db );

                // Get pageIDs data from the `page` table
                $this->profileDBIn();
                $res = $db->select( 'page', $this->getPageTableFields(), $set,
                                        __METHOD__ );
                $this->profileDBOut();

                // Hack: get the ns:titles stored in array(ns => array(titles)) format
                $this->initFromQueryResult( $db, $res, $linkBatch->data, true ); // process Titles

                // Resolve any found redirects
                $this->resolvePendingRedirects();
        }

        /**
         * Does the same as initFromTitles(), but is based on page IDs instead
         * @param $pageids array of page IDs
         */
        private function initFromPageIds( $pageids ) {
                if ( !count( $pageids ) ) {
                        return;
                }

                $pageids = array_map( 'intval', $pageids ); // paranoia
                $set = array(
                        'page_id' => $pageids
                );
                $db = $this->getDB();

                // Get pageIDs data from the `page` table
                $this->profileDBIn();
                $res = $db->select( 'page', $this->getPageTableFields(), $set,
                                        __METHOD__ );
                $this->profileDBOut();

                $remaining = array_flip( $pageids );
                $this->initFromQueryResult( $db, $res, $remaining, false );     // process PageIDs

                // Resolve any found redirects
                $this->resolvePendingRedirects();
        }

        /**
         * Iterate through the result of the query on 'page' table,
         * and for each row create and store title object and save any extra fields requested.
         * @param $db Database
         * @param $res DB Query result
         * @param $remaining array of either pageID or ns/title elements (optional).
         *        If given, any missing items will go to $mMissingPageIDs and $mMissingTitles
         * @param $processTitles bool Must be provided together with $remaining.
         *        If true, treat $remaining as an array of [ns][title]
         *        If false, treat it as an array of [pageIDs]
         */
        private function initFromQueryResult( $db, $res, &$remaining = null, $processTitles = null ) {
                if ( !is_null( $remaining ) && is_null( $processTitles ) ) {
                        ApiBase::dieDebug( __METHOD__, 'Missing $processTitles parameter when $remaining is provided' );
                }

                while ( $row = $db->fetchObject( $res ) ) {
                        $pageId = intval( $row->page_id );

                        // Remove found page from the list of remaining items
                        if ( isset( $remaining ) ) {
                                if ( $processTitles ) {
                                        unset( $remaining[$row->page_namespace][$row->page_title] );
                                } else {
                                        unset( $remaining[$pageId] );
                                }
                        }

                        // Store any extra fields requested by modules
                        $this->processDbRow( $row );
                }
                $db->freeResult( $res );

                if ( isset( $remaining ) ) {
                        // Any items left in the $remaining list are added as missing
                        if ( $processTitles ) {
                                // The remaining titles in $remaining are non-existent pages
                                foreach ( $remaining as $ns => $dbkeys ) {
                                        foreach ( $dbkeys as $dbkey => $unused ) {
                                                $title = Title::makeTitle( $ns, $dbkey );
                                                $this->mAllPages[$ns][$dbkey] = $this->mFakePageId;
                                                $this->mMissingTitles[$this->mFakePageId] = $title;
                                                $this->mFakePageId--;
                                                $this->mTitles[] = $title;
                                        }
                                }
                        } else {
                                // The remaining pageids do not exist
                                if ( !$this->mMissingPageIDs ) {
                                        $this->mMissingPageIDs = array_keys( $remaining );
                                } else {
                                        $this->mMissingPageIDs = array_merge( $this->mMissingPageIDs, array_keys( $remaining ) );
                                }
                        }
                }
        }

        /**
         * Does the same as initFromTitles(), but is based on revision IDs
         * instead
         * @param $revids array of revision IDs
         */
        private function initFromRevIDs( $revids ) {
                if ( !count( $revids ) ) {
                        return;
                }

                $revids = array_map( 'intval', $revids ); // paranoia
                $db = $this->getDB();
                $pageids = array();
                $remaining = array_flip( $revids );

                $tables = array( 'revision', 'page' );
                $fields = array( 'rev_id', 'rev_page' );
                $where = array( 'rev_id' => $revids, 'rev_page = page_id' );

                // Get pageIDs data from the `page` table
                $this->profileDBIn();
                $res = $db->select( $tables, $fields, $where,  __METHOD__ );
                while ( $row = $db->fetchObject( $res ) ) {
                        $revid = intval( $row->rev_id );
                        $pageid = intval( $row->rev_page );
                        $this->mGoodRevIDs[$revid] = $pageid;
                        $pageids[$pageid] = '';
                        unset( $remaining[$revid] );
                }
                $db->freeResult( $res );
                $this->profileDBOut();

                $this->mMissingRevIDs = array_keys( $remaining );

                // Populate all the page information
                $this->initFromPageIds( array_keys( $pageids ) );
        }

        /**
         * Resolve any redirects in the result if redirect resolution was
         * requested. This function is called repeatedly until all redirects
         * have been resolved.
         */
        private function resolvePendingRedirects() {
                if ( $this->mResolveRedirects ) {
                        $db = $this->getDB();
                        $pageFlds = $this->getPageTableFields();

                        // Repeat until all redirects have been resolved
                        // The infinite loop is prevented by keeping all known pages in $this->mAllPages
                        while ( $this->mPendingRedirectIDs ) {
                                // Resolve redirects by querying the pagelinks table, and repeat the process
                                // Create a new linkBatch object for the next pass
                                $linkBatch = $this->getRedirectTargets();

                                if ( $linkBatch->isEmpty() ) {
                                        break;
                                }

                                $set = $linkBatch->constructSet( 'page', $db );
                                if ( $set === false ) {
                                        break;
                                }

                                // Get pageIDs data from the `page` table
                                $this->profileDBIn();
                                $res = $db->select( 'page', $pageFlds, $set, __METHOD__ );
                                $this->profileDBOut();

                                // Hack: get the ns:titles stored in array(ns => array(titles)) format
                                $this->initFromQueryResult( $db, $res, $linkBatch->data, true );
                        }
                }
        }

        /**
         * Get the targets of the pending redirects from the database
         *
         * Also creates entries in the redirect table for redirects that don't
         * have one.
         * @return LinkBatch
         */
        private function getRedirectTargets() {
                $lb = new LinkBatch();
                $db = $this->getDB();

                $this->profileDBIn();
                $res = $db->select(
                        'redirect',
                        array(
                                'rd_from',
                                'rd_namespace',
                                'rd_title'
                        ), array( 'rd_from' => array_keys( $this->mPendingRedirectIDs ) ),
                        __METHOD__
                );
                $this->profileDBOut();

                while ( $row = $db->fetchObject( $res ) ) {
                        $rdfrom = intval( $row->rd_from );
                        $from = $this->mPendingRedirectIDs[$rdfrom]->getPrefixedText();
                        $to = Title::makeTitle( $row->rd_namespace, $row->rd_title )->getPrefixedText();
                        unset( $this->mPendingRedirectIDs[$rdfrom] );
                        if ( !isset( $this->mAllPages[$row->rd_namespace][$row->rd_title] ) ) {
                                $lb->add( $row->rd_namespace, $row->rd_title );
                        }
                        $this->mRedirectTitles[$from] = $to;
                }
                $db->freeResult( $res );
                if ( $this->mPendingRedirectIDs ) {
                        // We found pages that aren't in the redirect table
                        // Add them
                        foreach ( $this->mPendingRedirectIDs as $id => $title ) {
                                $article = new Article( $title );
                                $rt = $article->insertRedirect();
                                if ( !$rt ) {
                                        // What the hell. Let's just ignore this
                                        continue;
                                }
                                $lb->addObj( $rt );
                                $this->mRedirectTitles[$title->getPrefixedText()] = $rt->getPrefixedText();
                                unset( $this->mPendingRedirectIDs[$id] );
                        }
                }
                return $lb;
        }

        /**
         * Given an array of title strings, convert them into Title objects.
         * Alternativelly, an array of Title objects may be given.
         * This method validates access rights for the title,
         * and appends normalization values to the output.
         *
         * @param $titles array of Title objects or strings
         * @return LinkBatch
         */
        private function processTitlesArray( $titles ) {
                $linkBatch = new LinkBatch();

                foreach ( $titles as $title ) {
                        $titleObj = is_string( $title ) ? Title::newFromText( $title ) : $title;
                        if ( !$titleObj ) {
                                // Handle invalid titles gracefully
                                $this->mAllpages[0][$title] = $this->mFakePageId;
                                $this->mInvalidTitles[$this->mFakePageId] = $title;
                                $this->mFakePageId--;
                                continue; // There's nothing else we can do
                        }
                        $iw = $titleObj->getInterwiki();
                        if ( strval( $iw ) !== '' ) {
                                // This title is an interwiki link.
                                $this->mInterwikiTitles[$titleObj->getPrefixedText()] = $iw;
                        } else {
                                // Validation
                                if ( $titleObj->getNamespace() < 0 ) {
                                        $this->setWarning( 'No support for special pages has been implemented' );
                                } else {
                                        $linkBatch->addObj( $titleObj );
                                }
                        }

                        // Make sure we remember the original title that was
                        // given to us. This way the caller can correlate new
                        // titles with the originally requested when e.g. the
                        // namespace is localized or the capitalization is
                        // different
                        if ( is_string( $title ) && $title !== $titleObj->getPrefixedText() ) {
                                $this->mNormalizedTitles[$title] = $titleObj->getPrefixedText();
                        }
                }

                return $linkBatch;
        }

        protected function getAllowedParams() {
                return array(
                        'titles' => array(
                                ApiBase::PARAM_ISMULTI => true
                        ),
                        'pageids' => array(
                                ApiBase::PARAM_TYPE => 'integer',
                                ApiBase::PARAM_ISMULTI => true
                        ),
                        'revids' => array(
                                ApiBase::PARAM_TYPE => 'integer',
                                ApiBase::PARAM_ISMULTI => true
                        )
                );
        }

        protected function getParamDescription() {
                return array(
                        'titles' => 'A list of titles to work on',
                        'pageids' => 'A list of page IDs to work on',
                        'revids' => 'A list of revision IDs to work on'
                );
        }

        public function getPossibleErrors() {
                return array_merge( parent::getPossibleErrors(), array(
                        array( 'code' => 'multisource', 'info' => "Cannot use 'pageids' at the same time as 'dataSource'" ),
                        array( 'code' => 'multisource', 'info' => "Cannot use 'revids' at the same time as 'dataSource'" ),
                ) );
        }

        public function getVersion() {
                return __CLASS__ . ': $Id$';
        }
}