* (bug 12584) Don't reset cl_timestamp when auto-updating sort key on move

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

<?php

/*
 * Created on Sep 24, 2006
 *
 * API for MediaWiki 1.8+
 *
 * Copyright (C) 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 data page data requested.
 * 
 * When generator is used, the result of the generator will become the input for the
 * second instance of this class, and all subsequent actions will go use the second instance
 * for all their work. 
 * 
 * @addtogroup API
 */
class ApiPageSet extends ApiQueryBase {

        private $mAllPages; // [ns][dbkey] => page_id or 0 when missing
        private $mTitles, $mGoodTitles, $mMissingTitles, $mMissingPageIDs, $mRedirectTitles;
        private $mNormalizedTitles, $mInterwikiTitles;
        private $mResolveRedirects, $mPendingRedirectIDs;
        private $mGoodRevIDs, $mMissingRevIDs;
        private $mFakePageId;

        private $mRequestedPageFields;

        public function __construct($query, $resolveRedirects = false) {
                parent :: __construct($query, __CLASS__);

                $this->mAllPages = array ();
                $this->mTitles = array();
                $this->mGoodTitles = array ();
                $this->mMissingTitles = 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;
        }

        public function isResolvingRedirects() {
                return $this->mResolveRedirects;
        }

        public function requestField($fieldName) {
                $this->mRequestedPageFields[$fieldName] = null;
        }

        public function getCustomField($fieldName) {
                return $this->mRequestedPageFields[$fieldName];
        }

        /**
         * Get fields that modules have requested from the page table
         */
        public function getPageTableFields() {
                // Ensure we get minimum required fields
                $pageFlds = array (
                        'page_id' => null,
                        'page_namespace' => null,
                        'page_title' => null
                );

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

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

                $pageFlds = array_merge($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
         */
        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.
         */
        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.
         */
        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;
        }

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

        /**
         * Get a list of redirects when doing redirect resolution
         * @return array prefixed_title (string) => prefixed_title (string)
         */
        public function getRedirectTitles() {
                return $this->mRedirectTitles;
        }

        /**
         * Get a list of title normalizations - maps the title given 
         * with 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 the title given 
         * with to the 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 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)
         */
        public function getRevisionCount() {
                return count($this->getRevisionIDs());
        }

        /**
         * Populate from the request parameters
         */
        public function execute() {
                $this->profileIn();
                $titles = $pageids = $revids = null;
                extract($this->extractRequestParams());

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

                switch ($dataSource) {
                        case 'titles' :
                                $this->initFromTitles($titles);
                                break;
                        case 'pageids' :
                                $this->initFromPageIds($pageids);
                                break;
                        case 'revids' :
                                if($this->mResolveRedirects)
                                        $this->dieUsage('revids may not be used with redirect resolution', 'params');
                                $this->initFromRevIDs($revids);
                                break;
                        default :
                                // Do nothing - some queries do not need any of the data sources.
                                break;
                }
                $this->profileOut();
        }

        /**
         * Initialize PageSet from a list of Titles
         */
        public function populateFromTitles($titles) {
                $this->profileIn();
                $this->initFromTitles($titles);
                $this->profileOut();
        }

        /**
         * Initialize PageSet from a list of Page IDs
         */
        public function populateFromPageIDs($pageIDs) {
                $this->profileIn();
                $this->initFromPageIds($pageIDs);
                $this->profileOut();
        }

        /**
         * Initialize PageSet from a rowset returned from the database
         */
        public function populateFromQueryResult($db, $queryResult) {
                $this->profileIn();
                $this->initFromQueryResult($db, $queryResult);
                $this->profileOut();
        }

        /**
         * Initialize PageSet from a list of Revision IDs
         */
        public function populateFromRevisionIDs($revIDs) {
                $this->profileIn();
                $revIDs = array_map('intval', $revIDs); // paranoia
                $this->initFromRevIDs($revIDs);
                $this->profileOut();
        }

        /**
         * Extract all requested fields from the row received from the database
         */
        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;
        }
        
        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 links from `pagelinks` table.
         * #5 Substitute the original LinkBatch object with the new list
         * #6 Repeat from step #1     
         */
        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();
        }

        private function initFromPageIds($pageids) {
                if(empty($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();
                
                $this->initFromQueryResult($db, $res, array_flip($pageids), 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 $remaining as an array of [ns][title]
         *        If false, treat it as an array of [pageIDs]
         * @return Array of redirect IDs (only when resolving redirects)
         */
        private function initFromQueryResult($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 $remaining are non-existant pages
                                foreach ($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[] = $title;
                                        }
                                }
                        }
                        else
                        {
                                // The remaining pageids do not exist
                                if(empty($this->mMissingPageIDs))
                                        $this->mMissingPageIDs = array_keys($remaining);
                                else
                                        $this->mMissingPageIDs = array_merge($this->mMissingPageIDs, array_keys($remaining));
                        }
                }
        }

        private function initFromRevIDs($revids) {

                if(empty($revids))
                        return;
                        
                $db = $this->getDB();
                $pageids = array();
                $remaining = array_flip($revids);
                
                $tables = array('revision');
                $fields = array('rev_id','rev_page');
                $where = array('rev_deleted' => 0, 'rev_id' => $revids);
                
                // 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
                if($this->mResolveRedirects)
                        ApiBase :: dieDebug(__METHOD__, 'revids may not be used with redirect resolution');
                $this->initFromPageIds(array_keys($pageids));
        }

        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 $this->mAllPages
                        while (!empty ($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(false === $set)
                                        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);
                        }
                }
        }

        private function getRedirectTargets() {

                $linkBatch = new LinkBatch();
                $db = $this->getDB();

                // find redirect targets for all redirect pages
                $this->profileDBIn();
                $res = $db->select('pagelinks', array (
                        'pl_from',
                        'pl_namespace',
                        'pl_title'
                ), array (
                        'pl_from' => array_keys($this->mPendingRedirectIDs
                )), __METHOD__);
                $this->profileDBOut();

                while ($row = $db->fetchObject($res)) {

                        $plfrom = intval($row->pl_from);

                        // Bug 7304 workaround 
                        // ( http://bugzilla.wikipedia.org/show_bug.cgi?id=7304 )
                        // A redirect page may have more than one link.
                        // This code will only use the first link returned. 
                        if (isset ($this->mPendingRedirectIDs[$plfrom])) { // remove line when bug 7304 is fixed 

                                $titleStrFrom = $this->mPendingRedirectIDs[$plfrom]->getPrefixedText();
                                $titleStrTo = Title :: makeTitle($row->pl_namespace, $row->pl_title)->getPrefixedText();
                                unset ($this->mPendingRedirectIDs[$plfrom]); // remove line when bug 7304 is fixed

                                // Avoid an infinite loop by checking if we have already processed this target
                                if (!isset ($this->mAllPages[$row->pl_namespace][$row->pl_title])) {
                                        $linkBatch->add($row->pl_namespace, $row->pl_title);
                                }
                        } else {
                                // This redirect page has more than one link.
                                // This is very slow, but safer until bug 7304 is resolved
                                $title = Title :: newFromID($plfrom);
                                $titleStrFrom = $title->getPrefixedText();

                                $article = new Article($title);
                                $text = $article->getContent();
                                $titleTo = Title :: newFromRedirect($text);
                                $titleStrTo = $titleTo->getPrefixedText();

                                if (is_null($titleStrTo))
                                        ApiBase :: dieDebug(__METHOD__, 'Bug7304 workaround: redir target from {$title->getPrefixedText()} not found');

                                // Avoid an infinite loop by checking if we have already processed this target
                                if (!isset ($this->mAllPages[$titleTo->getNamespace()][$titleTo->getDBkey()])) {
                                        $linkBatch->addObj($titleTo);
                                }
                        }

                        $this->mRedirectTitles[$titleStrFrom] = $titleStrTo;
                }
                $db->freeResult($res);

                // All IDs must exist in the page table
                if (!empty($this->mPendingRedirectIDs[$plfrom]))
                        ApiBase :: dieDebug(__METHOD__, 'Invalid redirect IDs were found');

                return $linkBatch;
        }

        /**
         * 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.
         * 
         * @return LinkBatch of title objects.
         */
        private function processTitlesArray($titles) {

                $linkBatch = new LinkBatch();

                foreach ($titles as $title) {
                        
                        $titleObj = is_string($title) ? Title :: newFromText($title) : $title;
                        if (!$titleObj)
                                $this->dieUsage("bad title", 'invalidtitle');

                        $iw = $titleObj->getInterwiki();
                        if (!empty($iw)) {
                                // This title is an interwiki link.
                                $this->mInterwikiTitles[$titleObj->getPrefixedText()] = $iw;
                        } else { 

                                // Validation
                                if ($titleObj->getNamespace() < 0)
                                        $this->dieUsage("No support for special pages has been implemented", 'unsupportednamespace');

                                $linkBatch->addObj($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,
                        // i.e. namespace is localized or 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 getVersion() {
                return __CLASS__ . ': $Id$';
        }
}