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https://github.com/moodle/moodle.git
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388 lines
12 KiB
PHP
388 lines
12 KiB
PHP
<?php
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// This file is part of Moodle - http://moodle.org/
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//
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// Moodle is free software: you can redistribute it and/or modify
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// it under the terms of the GNU General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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//
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// Moodle is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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//
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// You should have received a copy of the GNU General Public License
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// along with Moodle. If not, see <http://www.gnu.org/licenses/>.
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/**
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* Base class for search engines.
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*
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* All search engines must extend this class.
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*
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* @package core_search
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* @copyright 2015 Daniel Neis
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* @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
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*/
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namespace core_search;
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defined('MOODLE_INTERNAL') || die();
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/**
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* Base class for search engines.
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*
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* All search engines must extend this class.
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*
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* @package core_search
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* @copyright 2015 Daniel Neis
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* @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
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*/
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abstract class engine {
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/**
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* The search engine configuration.
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*
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* @var stdClass
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*/
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protected $config = null;
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/**
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* Last executed query error, if there was any.
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* @var string
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*/
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protected $queryerror = null;
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/**
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* @var array Internal cache.
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*/
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protected $cachedareas = array();
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/**
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* @var array Internal cache.
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*/
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protected $cachedcourses = array();
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/**
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* User data required to show their fullnames. Indexed by userid.
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*
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* @var stdClass[]
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*/
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protected static $cachedusers = array();
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/**
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* @var string Frankenstyle plugin name.
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*/
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protected $pluginname = null;
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/**
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* Initialises the search engine configuration.
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*
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* Search engine availability should be checked separately.
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*
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* @return void
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*/
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public function __construct() {
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$classname = get_class($this);
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if (strpos($classname, '\\') === false) {
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throw new \coding_exception('"' . $classname . '" class should specify its component namespace and it should be named engine.');
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} else if (strpos($classname, '_') === false) {
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throw new \coding_exception('"' . $classname . '" class namespace should be its frankenstyle name');
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}
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// This is search_xxxx config.
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$this->pluginname = substr($classname, 0, strpos($classname, '\\'));
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if ($config = get_config($this->pluginname)) {
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$this->config = $config;
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} else {
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$this->config = new stdClass();
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}
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}
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/**
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* Returns a course instance checking internal caching.
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*
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* @param int $courseid
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* @return stdClass
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*/
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protected function get_course($courseid) {
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if (!empty($this->cachedcourses[$courseid])) {
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return $this->cachedcourses[$courseid];
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}
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// No need to clone, only read.
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$this->cachedcourses[$courseid] = get_course($courseid, false);
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return $this->cachedcourses[$courseid];
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}
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/**
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* Returns user data checking the internal static cache.
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*
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* Including here the minimum required user information as this may grow big.
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*
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* @param int $userid
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* @return stdClass
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*/
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public function get_user($userid) {
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global $DB;
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if (empty(self::$cachedusers[$userid])) {
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$fields = get_all_user_name_fields(true);
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self::$cachedusers[$userid] = $DB->get_record('user', array('id' => $userid), 'id, ' . $fields);
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}
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return self::$cachedusers[$userid];
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}
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/**
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* Returns a search instance of the specified area checking internal caching.
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*
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* @param string $areaid Area id
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* @return \core_search\base
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*/
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protected function get_search_area($areaid) {
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if (isset($this->cachedareas[$areaid]) && $this->cachedareas[$areaid] === false) {
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// We already checked that area and it is not available.
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return false;
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}
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if (!isset($this->cachedareas[$areaid])) {
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// First result that matches this area.
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$this->cachedareas[$areaid] = \core_search\manager::get_search_area($areaid);
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if ($this->cachedareas[$areaid] === false) {
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// The area does not exist or it is not available any more.
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$this->cachedareas[$areaid] = false;
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return false;
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}
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if (!$this->cachedareas[$areaid]->is_enabled()) {
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// We skip the area if it is not enabled.
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// Marking it as false so next time we don' need to check it again.
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$this->cachedareas[$areaid] = false;
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return false;
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}
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}
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return $this->cachedareas[$areaid];
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}
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/**
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* Returns a document instance prepared to be rendered.
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*
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* @param \core_search\base $searcharea
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* @param array $docdata
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* @return \core_search\document
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*/
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protected function to_document(\core_search\base $searcharea, $docdata) {
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list($componentname, $areaname) = \core_search\manager::extract_areaid_parts($docdata['areaid']);
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$doc = \core_search\document_factory::instance($docdata['itemid'], $componentname, $areaname, $this);
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$doc->set_data_from_engine($docdata);
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$doc->set_doc_url($searcharea->get_doc_url($doc));
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$doc->set_context_url($searcharea->get_context_url($doc));
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// Uses the internal caches to get required data needed to render the document later.
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$course = $this->get_course($doc->get('courseid'));
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$doc->set_extra('coursefullname', $course->fullname);
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if ($doc->is_set('userid')) {
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$user = $this->get_user($doc->get('userid'));
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$doc->set_extra('userfullname', fullname($user));
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}
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return $doc;
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}
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/**
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* Returns the plugin name.
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*
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* @return string Frankenstyle plugin name.
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*/
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public function get_plugin_name() {
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return $this->pluginname;
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}
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/**
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* Gets the document class used by this search engine.
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*
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* Search engines can overwrite \core_search\document with \search_ENGINENAME\document class.
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*
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* Looks for a document class in the current search engine namespace, falling back to \core_search\document.
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* Publicly available because search areas do not have access to the engine details,
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* \core_search\document_factory accesses this function.
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*
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* @return string
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*/
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public function get_document_classname() {
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$classname = $this->pluginname . '\\document';
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if (!class_exists($classname)) {
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$classname = '\\core_search\\document';
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}
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return $classname;
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}
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/**
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* Run any pre-indexing operations.
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*
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* Should be overwritten if the search engine needs to do any pre index preparation.
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*
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* @param bool $fullindex True if a full index will be performed
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* @return void
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*/
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public function index_starting($fullindex = false) {
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// Nothing by default.
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}
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/**
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* Run any post indexing operations.
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*
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* Should be overwritten if the search engine needs to do any post index cleanup.
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*
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* @param int $numdocs The number of documents that were added to the index
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* @param bool $fullindex True if a full index was performed
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* @return void
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*/
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public function index_complete($numdocs = 0, $fullindex = false) {
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// Nothing by default.
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}
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/**
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* Do anything that may need to be done before an area is indexed.
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*
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* @param \core_search\base $searcharea The search area that was complete
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* @param bool $fullindex True if a full index is being performed
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* @return void
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*/
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public function area_index_starting($searcharea, $fullindex = false) {
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// Nothing by default.
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}
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/**
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* Do any area cleanup needed, and do anything to confirm contents.
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*
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* Return false to prevent the search area completed time and stats from being updated.
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*
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* @param \core_search\base $searcharea The search area that was complete
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* @param int $numdocs The number of documents that were added to the index
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* @param bool $fullindex True if a full index is being performed
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* @return bool True means that data is considered indexed
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*/
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public function area_index_complete($searcharea, $numdocs = 0, $fullindex = false) {
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return true;
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}
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/**
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* Optimizes the search engine.
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*
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* Should be overwritten if the search engine can optimize its contents.
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*
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* @return void
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*/
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public function optimize() {
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// Nothing by default.
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}
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/**
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* Does the system satisfy all the requirements.
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*
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* Should be overwritten if the search engine has any system dependencies
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* that needs to be checked.
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*
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* @return bool
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*/
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public function is_installed() {
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return true;
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}
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/**
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* Returns any error reported by the search engine when executing the provided query.
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*
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* It should be called from static::execute_query when an exception is triggered.
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*
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* @return string
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*/
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public function get_query_error() {
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return $this->queryerror;
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}
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/**
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* Returns the total number of documents available for the most recent call to execute_query.
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*
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* This can be an estimate, but should get more accurate the higher the limited passed to execute_query is.
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* To do that, the engine can use (actual result returned count + count of unchecked documents), or
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* (total possible docs - docs that have been checked and rejected).
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*
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* Engine can limit to manager::MAX_RESULTS if there is cost to determining more.
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* If this cannot be computed in a reasonable way, manager::MAX_RESULTS may be returned.
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*
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* @return int
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*/
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abstract public function get_query_total_count();
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/**
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* Return true if file indexing is supported and enabled. False otherwise.
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*
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* @return bool
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*/
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public function file_indexing_enabled() {
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return false;
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}
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/**
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* Clears the current query error value.
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*
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* @return void
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*/
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public function clear_query_error() {
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$this->queryerror = null;
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}
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/**
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* Is the server ready to use?
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*
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* This should also check that the search engine configuration is ok.
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*
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* @return true|string Returns true if all good or an error string.
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*/
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abstract function is_server_ready();
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/**
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* Adds a document to the search engine.
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*
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* @param document $document
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* @param bool $fileindexing True if file indexing is to be used
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* @return bool False if the file was skipped or failed, true on success
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*/
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abstract function add_document($document, $fileindexing = false);
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/**
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* Executes the query on the engine.
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*
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* Implementations of this function should check user context array to limit the results to contexts where the
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* user have access. They should also limit the owneruserid field to manger::NO_OWNER_ID or the current user's id.
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* Engines must use area->check_access() to confirm user access.
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*
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* Engines should reasonably attempt to fill up to limit with valid results if they are available.
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*
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* @param stdClass $filters Query and filters to apply.
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* @param array $usercontexts Contexts where the user has access. True if the user can access all contexts.
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* @param int $limit The maximum number of results to return. If empty, limit to manager::MAX_RESULTS.
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* @return \core_search\document[] Results or false if no results
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*/
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abstract function execute_query($filters, $usercontexts, $limit = 0);
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/**
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* Delete all documents.
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*
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* @param string $areaid To filter by area
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* @return void
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*/
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abstract function delete($areaid = null);
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}
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