return \core_course\output\course_module_name::update($itemid, $newvalue);
}
}
+
+/**
+ * Returns course modules tagged with a specified tag ready for output on tag/index.php page
+ *
+ * This is a callback used by the tag area core/course_modules to search for course modules
+ * tagged with a specific tag.
+ *
+ * @param core_tag_tag $tag
+ * @param bool $exclusivemode if set to true it means that no other entities tagged with this tag
+ * are displayed on the page and the per-page limit may be bigger
+ * @param int $fromcontextid context id where the link was displayed, may be used by callbacks
+ * to display items in the same context first
+ * @param int $contextid context id where to search for records
+ * @param bool $recursivecontext search in subcontexts as well
+ * @param int $page 0-based number of page being displayed
+ * @return \core_tag\output\tagindex
+ */
+function course_get_tagged_course_modules($tag, $exclusivemode = false, $fromcontextid = 0, $contextid = 0,
+ $recursivecontext = 1, $page = 0) {
+ global $OUTPUT;
+ $perpage = $exclusivemode ? 20 : 5;
+
+ // Build select query.
+ $ctxselect = context_helper::get_preload_record_columns_sql('ctx');
+ $query = "SELECT cm.id AS cmid, c.id AS courseid, $ctxselect
+ FROM {course_modules} cm
+ JOIN {tag_instance} tt ON cm.id = tt.itemid
+ JOIN {course} c ON cm.course = c.id
+ JOIN {context} ctx ON ctx.instanceid = cm.id AND ctx.contextlevel = :coursemodulecontextlevel
+ WHERE tt.itemtype = :itemtype AND tt.tagid = :tagid AND tt.component = :component
+ AND c.id %COURSEFILTER% AND cm.id %ITEMFILTER%";
+
+ $params = array('itemtype' => 'course_modules', 'tagid' => $tag->id, 'component' => 'core',
+ 'coursemodulecontextlevel' => CONTEXT_MODULE);
+ if ($contextid) {
+ $context = context::instance_by_id($contextid);
+ $query .= $recursivecontext ? ' AND (ctx.id = :contextid OR ctx.path LIKE :path)' : ' AND ctx.id = :contextid';
+ $params['contextid'] = $context->id;
+ $params['path'] = $context->path.'/%';
+ }
+
+ $query .= ' ORDER BY';
+ if ($fromcontextid) {
+ // In order-clause specify that modules from inside "fromctx" context should be returned first.
+ $fromcontext = context::instance_by_id($fromcontextid);
+ $query .= ' (CASE WHEN ctx.id = :fromcontextid OR ctx.path LIKE :frompath THEN 0 ELSE 1 END),';
+ $params['fromcontextid'] = $fromcontext->id;
+ $params['frompath'] = $fromcontext->path.'/%';
+ }
+ $query .= ' c.sortorder, cm.id';
+ $totalpages = $page + 1;
+
+ // Use core_tag_index_builder to build and filter the list of items.
+ // Request one item more than we need so we know if next page exists.
+ $builder = new core_tag_index_builder('core', 'course_modules', $query, $params, $page * $perpage, $perpage + 1);
+ while ($item = $builder->has_item_that_needs_access_check()) {
+ context_helper::preload_from_record($item);
+ $courseid = $item->courseid;
+ if (!$builder->can_access_course($courseid)) {
+ $builder->set_accessible($item, false);
+ continue;
+ }
+ $modinfo = get_fast_modinfo($builder->get_course($courseid));
+ // Set accessibility of this item and all other items in the same course.
+ $builder->walk(function ($taggeditem) use ($courseid, $modinfo, $builder) {
+ if ($taggeditem->courseid == $courseid) {
+ $cm = $modinfo->get_cm($taggeditem->cmid);
+ $builder->set_accessible($taggeditem, $cm->uservisible);
+ }
+ });
+ }
+
+ $items = $builder->get_items();
+ if (count($items) > $perpage) {
+ $totalpages = $page + 2; // We don't need exact page count, just indicate that the next page exists.
+ array_pop($items);
+ }
+
+ // Build the display contents.
+ if ($items) {
+ $tagfeed = new core_tag\output\tagfeed();
+ foreach ($items as $item) {
+ context_helper::preload_from_record($item);
+ $course = $builder->get_course($item->courseid);
+ $modinfo = get_fast_modinfo($course);
+ $cm = $modinfo->get_cm($item->cmid);
+ $courseurl = course_get_url($item->courseid, $cm->sectionnum);
+ $cmname = $cm->get_formatted_name();
+ if (!$exclusivemode) {
+ $cmname = shorten_text($cmname, 100);
+ }
+ $cmname = html_writer::link($cm->url?:$courseurl, $cmname);
+ $coursename = format_string($course->fullname, true,
+ array('context' => context_course::instance($item->courseid)));
+ $coursename = html_writer::link($courseurl, $coursename);
+ $icon = html_writer::empty_tag('img', array('src' => $cm->get_icon_url()));
+ $tagfeed->add($icon, $cmname, $coursename);
+ }
+
+ $content = $OUTPUT->render_from_template('core_tag/tagfeed',
+ $tagfeed->export_for_template($OUTPUT));
+
+ return new core_tag\output\tagindex($tag, 'core', 'course_modules', $content,
+ $exclusivemode, $fromcontextid, $contextid, $recursivecontext, $page, $totalpages);
+ }
+}
$this->assertEquals('New forum name', $res['value']);
$this->assertEquals('New forum name', $DB->get_field('forum', 'name', array('id' => $forum->id)));
}
+
+ /**
+ * Testing function course_get_tagged_course_modules - search tagged course modules
+ */
+ public function test_course_get_tagged_course_modules() {
+ global $DB;
+ $this->resetAfterTest();
+ $course3 = $this->getDataGenerator()->create_course();
+ $course2 = $this->getDataGenerator()->create_course();
+ $course1 = $this->getDataGenerator()->create_course();
+ $cm11 = $this->getDataGenerator()->create_module('assign', array('course' => $course1->id,
+ 'tags' => 'Cat, Dog'));
+ $cm12 = $this->getDataGenerator()->create_module('page', array('course' => $course1->id,
+ 'tags' => 'Cat, Mouse', 'visible' => 0));
+ $cm13 = $this->getDataGenerator()->create_module('page', array('course' => $course1->id,
+ 'tags' => 'Cat, Mouse, Dog'));
+ $cm21 = $this->getDataGenerator()->create_module('forum', array('course' => $course2->id,
+ 'tags' => 'Cat, Mouse'));
+ $cm31 = $this->getDataGenerator()->create_module('forum', array('course' => $course3->id,
+ 'tags' => 'Cat, Mouse'));
+
+ // Admin is able to view everything.
+ $this->setAdminUser();
+ $res = course_get_tagged_course_modules(core_tag_tag::get_by_name(0, 'Cat'),
+ /*$exclusivemode = */false, /*$fromctx = */0, /*$ctx = */0, /*$rec = */1, /*$page = */0);
+ $this->assertRegExp('/'.$cm11->name.'/', $res->content);
+ $this->assertRegExp('/'.$cm12->name.'/', $res->content);
+ $this->assertRegExp('/'.$cm13->name.'/', $res->content);
+ $this->assertRegExp('/'.$cm21->name.'/', $res->content);
+ $this->assertRegExp('/'.$cm31->name.'/', $res->content);
+ // Results from course1 are returned before results from course2.
+ $this->assertTrue(strpos($res->content, $cm11->name) < strpos($res->content, $cm21->name));
+
+ // Ordinary user is not able to see anything.
+ $user = $this->getDataGenerator()->create_user();
+ $this->setUser($user);
+
+ $res = course_get_tagged_course_modules(core_tag_tag::get_by_name(0, 'Cat'),
+ /*$exclusivemode = */false, /*$fromctx = */0, /*$ctx = */0, /*$rec = */1, /*$page = */0);
+ $this->assertNull($res);
+
+ // Enrol user as student in course1 and course2.
+ $roleids = $DB->get_records_menu('role', null, '', 'shortname, id');
+ $this->getDataGenerator()->enrol_user($user->id, $course1->id, $roleids['student']);
+ $this->getDataGenerator()->enrol_user($user->id, $course2->id, $roleids['student']);
+ core_tag_index_builder::reset_caches();
+
+ // Searching in the course context returns visible modules in this course.
+ $context = context_course::instance($course1->id);
+ $res = course_get_tagged_course_modules(core_tag_tag::get_by_name(0, 'Cat'),
+ /*$exclusivemode = */false, /*$fromctx = */0, /*$ctx = */$context->id, /*$rec = */1, /*$page = */0);
+ $this->assertRegExp('/'.$cm11->name.'/', $res->content);
+ $this->assertNotRegExp('/'.$cm12->name.'/', $res->content);
+ $this->assertRegExp('/'.$cm13->name.'/', $res->content);
+ $this->assertNotRegExp('/'.$cm21->name.'/', $res->content);
+ $this->assertNotRegExp('/'.$cm31->name.'/', $res->content);
+
+ // Searching FROM the course context returns visible modules in all courses.
+ $context = context_course::instance($course2->id);
+ $res = course_get_tagged_course_modules(core_tag_tag::get_by_name(0, 'Cat'),
+ /*$exclusivemode = */false, /*$fromctx = */$context->id, /*$ctx = */0, /*$rec = */1, /*$page = */0);
+ $this->assertRegExp('/'.$cm11->name.'/', $res->content);
+ $this->assertNotRegExp('/'.$cm12->name.'/', $res->content);
+ $this->assertRegExp('/'.$cm13->name.'/', $res->content);
+ $this->assertRegExp('/'.$cm21->name.'/', $res->content);
+ $this->assertNotRegExp('/'.$cm31->name.'/', $res->content); // No access to course3.
+ // Results from course2 are returned before results from course1.
+ $this->assertTrue(strpos($res->content, $cm21->name) < strpos($res->content, $cm11->name));
+
+ // Enrol user in course1 as a teacher - now he should be able to see hidden module.
+ $this->getDataGenerator()->enrol_user($user->id, $course1->id, $roleids['editingteacher']);
+ get_fast_modinfo(0,0,true);
+
+ $context = context_course::instance($course1->id);
+ $res = course_get_tagged_course_modules(core_tag_tag::get_by_name(0, 'Cat'),
+ /*$exclusivemode = */false, /*$fromctx = */$context->id, /*$ctx = */0, /*$rec = */1, /*$page = */0);
+ $this->assertRegExp('/'.$cm12->name.'/', $res->content);
+
+ // Create more modules and try pagination.
+ $cm14 = $this->getDataGenerator()->create_module('assign', array('course' => $course1->id,
+ 'tags' => 'Cat, Dog'));
+ $cm15 = $this->getDataGenerator()->create_module('page', array('course' => $course1->id,
+ 'tags' => 'Cat, Mouse', 'visible' => 0));
+ $cm16 = $this->getDataGenerator()->create_module('page', array('course' => $course1->id,
+ 'tags' => 'Cat, Mouse, Dog'));
+
+ $context = context_course::instance($course1->id);
+ $res = course_get_tagged_course_modules(core_tag_tag::get_by_name(0, 'Cat'),
+ /*$exclusivemode = */false, /*$fromctx = */0, /*$ctx = */$context->id, /*$rec = */1, /*$page = */0);
+ $this->assertRegExp('/'.$cm11->name.'/', $res->content);
+ $this->assertRegExp('/'.$cm12->name.'/', $res->content);
+ $this->assertRegExp('/'.$cm13->name.'/', $res->content);
+ $this->assertNotRegExp('/'.$cm21->name.'/', $res->content);
+ $this->assertRegExp('/'.$cm14->name.'/', $res->content);
+ $this->assertRegExp('/'.$cm15->name.'/', $res->content);
+ $this->assertNotRegExp('/'.$cm16->name.'/', $res->content);
+ $this->assertNotRegExp('/'.$cm31->name.'/', $res->content); // No access to course3.
+ $this->assertEmpty($res->prevpageurl);
+ $this->assertNotEmpty($res->nextpageurl);
+
+ $res = course_get_tagged_course_modules(core_tag_tag::get_by_name(0, 'Cat'),
+ /*$exclusivemode = */false, /*$fromctx = */0, /*$ctx = */$context->id, /*$rec = */1, /*$page = */1);
+ $this->assertNotRegExp('/'.$cm11->name.'/', $res->content);
+ $this->assertNotRegExp('/'.$cm12->name.'/', $res->content);
+ $this->assertNotRegExp('/'.$cm13->name.'/', $res->content);
+ $this->assertNotRegExp('/'.$cm21->name.'/', $res->content);
+ $this->assertNotRegExp('/'.$cm14->name.'/', $res->content);
+ $this->assertNotRegExp('/'.$cm15->name.'/', $res->content);
+ $this->assertRegExp('/'.$cm16->name.'/', $res->content);
+ $this->assertNotRegExp('/'.$cm31->name.'/', $res->content); // No access to course3.
+ $this->assertNotEmpty($res->prevpageurl);
+ $this->assertEmpty($res->nextpageurl);
+ }
}
$string['cachedef_observers'] = 'Event observers';
$string['cachedef_plugin_functions'] = 'Plugins available callbacks';
$string['cachedef_plugin_manager'] = 'Plugin info manager';
+$string['cachedef_tagindexbuilder'] = 'Search results for tagged items';
$string['cachedef_questiondata'] = 'Question definitions';
$string['cachedef_repositories'] = 'Repositories instances data';
$string['cachedef_grade_categories'] = 'Grade category queries';
'mode' => cache_store::MODE_REQUEST,
'simplekeys' => true,
'simpledata' => true
- )
+ ),
+
+ // Caches tag index builder results.
+ 'tagindexbuilder' => array(
+ 'mode' => cache_store::MODE_SESSION,
+ 'simplekeys' => true,
+ 'simplevalues' => true,
+ 'staticacceleration' => true,
+ 'staticaccelerationsize' => 10,
+ 'ttl' => 900, // 15 minutes.
+ 'invalidationevents' => array(
+ 'resettagindexbuilder',
+ ),
+ ),
);
array(
'itemtype' => 'course_modules', // Course modules.
'component' => 'core',
+ 'callback' => 'course_get_tagged_course_modules',
+ 'callbackfile' => '/course/lib.php',
),
);
--- /dev/null
+<?php
+// This file is part of Moodle - http://moodle.org/
+//
+// Moodle 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 3 of the License, or
+// (at your option) any later version.
+//
+// Moodle 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 Moodle. If not, see <http://www.gnu.org/licenses/>.
+
+/**
+ * Class core_tag_index_builder
+ *
+ * @package core_tag
+ * @copyright 2016 Marina Glancy
+ * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+
+defined('MOODLE_INTERNAL') || die();
+
+/**
+ * Helper to build tag index
+ *
+ * This can be used by components to implement tag area callbacks. This is especially
+ * useful for in-course content when we need to check and cache user's access to
+ * multiple courses. Course access and accessible items are stored in session cache
+ * with 15 minutes expiry time.
+ *
+ * Example of usage:
+ *
+ * $builder = new core_tag_index_builder($component, $itemtype, $sql, $params, $from, $limit);
+ * while ($item = $builder->has_item_that_needs_access_check()) {
+ * if (!$builder->can_access_course($item->courseid)) {
+ * $builder->set_accessible($item, false);
+ * } else {
+ * $accessible = true; // Check access and set $accessible respectively.
+ * $builder->set_accessible($item, $accessible);
+ * }
+ * }
+ * $items = $builder->get_items();
+ *
+ * @package core_tag
+ * @copyright 2016 Marina Glancy
+ * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+class core_tag_index_builder {
+
+ /** @var string component specified in the constructor */
+ protected $component;
+
+ /** @var string itemtype specified in the constructor */
+ protected $itemtype;
+
+ /** @var string SQL statement */
+ protected $sql;
+
+ /** @var array parameters for SQL statement */
+ protected $params;
+
+ /** @var int index from which to return records */
+ protected $from;
+
+ /** @var int maximum number of records to return */
+ protected $limit;
+
+ /** @var array result of SQL query */
+ protected $items;
+
+ /** @var array list of item ids ( array_keys($this->items) ) */
+ protected $itemkeys;
+
+ /** @var string alias of the item id in the SQL result */
+ protected $idfield = 'id';
+
+ /** @var array cache of items accessibility (id => bool) */
+ protected $accessibleitems;
+
+ /** @var array cache of courses accessibility (courseid => bool) */
+ protected $courseaccess;
+
+ /** @var bool indicates that items cache was changed in this class and needs pushing to MUC */
+ protected $cachechangedaccessible = false;
+
+ /** @var bool indicates that course accessibiity cache was changed in this class and needs pushing to MUC */
+ protected $cachechangedcourse = false;
+
+ /** @var array cached courses (not pushed to MUC) */
+ protected $courses;
+
+ /**
+ * Constructor.
+ *
+ * Specify the SQL query for retrieving the tagged items, SQL query must:
+ * - return the item id as the first field and make sure that it is unique in the result
+ * - provide ORDER BY that exclude any possibility of random results, if $fromctx was specified when searching
+ * for tagged items it is the best practice to make sure that items from this context are returned first.
+ *
+ * This query may also contain placeholders %COURSEFILTER% or %ITEMFILTER% that will be substituted with
+ * expressions excluding courses and/or filters that are already known as inaccessible.
+ *
+ * Example: "WHERE c.id %COURSEFILTER% AND cm.id %ITEMFILTER%"
+ *
+ * This query may contain fields to preload context if context is needed for formatting values.
+ *
+ * It is recommended to sort by course sortorder first, this way the items from the same course will be next to
+ * each other and the sequence of courses will the same in different tag areas.
+ *
+ * @param string $component component responsible for tagging
+ * @param string $itemtype type of item that is being tagged
+ * @param string $sql SQL query that would retrieve all relevant items without permission check
+ * @param array $params parameters for the query (must be named)
+ * @param int $from return a subset of records, starting at this point
+ * @param int $limit return a subset comprising this many records in total (this field is NOT optional)
+ */
+ public function __construct($component, $itemtype, $sql, $params, $from, $limit) {
+ $this->component = preg_replace('/[^A-Za-z0-9_]/i', '', $component);
+ $this->itemtype = preg_replace('/[^A-Za-z0-9_]/i', '', $itemtype);
+ $this->sql = $sql;
+ $this->params = $params;
+ $this->from = $from;
+ $this->limit = $limit;
+ $this->courses = array();
+ }
+
+ /**
+ * Substitute %COURSEFILTER% with an expression filtering out courses where current user does not have access
+ */
+ protected function prepare_sql_courses() {
+ global $DB;
+ if (!preg_match('/\\%COURSEFILTER\\%/', $this->sql)) {
+ return;
+ }
+ $this->init_course_access();
+ $unaccessiblecourses = array_filter($this->courseaccess, function($item) {
+ return !$item;
+ });
+ $idx = 0;
+ while (preg_match('/^([^\\0]*?)\\%COURSEFILTER\\%([^\\0]*)$/', $this->sql, $matches)) {
+ list($sql, $params) = $DB->get_in_or_equal(array_keys($unaccessiblecourses),
+ SQL_PARAMS_NAMED, 'ca_'.($idx++).'_', false, 0);
+ $this->sql = $matches[1].' '.$sql.' '.$matches[2];
+ $this->params += $params;
+ }
+ }
+
+ /**
+ * Substitute %ITEMFILTER% with an expression filtering out items where current user does not have access
+ */
+ protected function prepare_sql_items() {
+ global $DB;
+ if (!preg_match('/\\%ITEMFILTER\\%/', $this->sql)) {
+ return;
+ }
+ $this->init_items_access();
+ $unaccessibleitems = array_filter($this->accessibleitems, function($item) {
+ return !$item;
+ });
+ $idx = 0;
+ while (preg_match('/^([^\\0]*?)\\%ITEMFILTER\\%([^\\0]*)$/', $this->sql, $matches)) {
+ list($sql, $params) = $DB->get_in_or_equal(array_keys($unaccessibleitems),
+ SQL_PARAMS_NAMED, 'ia_'.($idx++).'_', false, 0);
+ $this->sql = $matches[1].' '.$sql.' '.$matches[2];
+ $this->params += $params;
+ }
+ }
+
+ /**
+ * Ensures that SQL query was executed and $this->items is filled
+ */
+ protected function retrieve_items() {
+ global $DB;
+ if ($this->items !== null) {
+ return;
+ }
+ $this->prepare_sql_courses();
+ $this->prepare_sql_items();
+ $this->items = $DB->get_records_sql($this->sql, $this->params);
+ $this->itemkeys = array_keys($this->items);
+ if ($this->items) {
+ // Find the name of the first key of the item - usually 'id' but can be something different.
+ // This must be a unique identifier of the item.
+ $firstitem = reset($this->items);
+ $firstitemarray = (array)$firstitem;
+ $this->idfield = key($firstitemarray);
+ }
+ }
+
+ /**
+ * Returns the filtered records from SQL query result.
+ *
+ * This function can only be executed after $builder->has_item_that_needs_access_check() returns null
+ *
+ *
+ * @return array
+ */
+ public function get_items() {
+ global $DB, $CFG;
+ if (is_siteadmin()) {
+ $this->sql = preg_replace('/\\%COURSEFILTER\\%/', '<>0', $this->sql);
+ $this->sql = preg_replace('/\\%ITEMFILTER\\%/', '<>0', $this->sql);
+ return $DB->get_records_sql($this->sql, $this->params, $this->from, $this->limit);
+ }
+ if ($CFG->debugdeveloper && $this->has_item_that_needs_access_check()) {
+ debugging('Caller must ensure that has_item_that_needs_access_check() does not return anything '
+ . 'before calling get_items(). The item list may be incomplete', DEBUG_DEVELOPER);
+ }
+ $this->retrieve_items();
+ $this->save_caches();
+ $idx = 0;
+ $items = array();
+ foreach ($this->itemkeys as $id) {
+ if (!array_key_exists($id, $this->accessibleitems) || !$this->accessibleitems[$id]) {
+ continue;
+ }
+ if ($idx >= $this->from) {
+ $items[$id] = $this->items[$id];
+ }
+ $idx++;
+ if ($idx >= $this->from + $this->limit) {
+ break;
+ }
+ }
+ return $items;
+ }
+
+ /**
+ * Returns the first row from the SQL result that we don't know whether it is accessible by user or not.
+ *
+ * This will return null when we have necessary number of accessible items to return in {@link get_items()}
+ *
+ * After analyzing you may decide to mark not only this record but all similar as accessible or not accessible.
+ * For example, if you already call get_fast_modinfo() to check this item's accessibility, why not mark all
+ * items in the same course as accessible or not accessible.
+ *
+ * Helpful methods: {@link set_accessible()} and {@link walk()}
+ *
+ * @return null|object
+ */
+ public function has_item_that_needs_access_check() {
+ if (is_siteadmin()) {
+ return null;
+ }
+ $this->retrieve_items();
+ $counter = 0; // Counter for accessible items.
+ foreach ($this->itemkeys as $id) {
+ if (!array_key_exists($id, $this->accessibleitems)) {
+ return (object)(array)$this->items[$id];
+ }
+ $counter += $this->accessibleitems[$id] ? 1 : 0;
+ if ($counter >= $this->from + $this->limit) {
+ // We found enough accessible items fot get_items() method, do not look any further.
+ return null;
+ }
+ }
+ return null;
+ }
+
+ /**
+ * Walk through the array of items and call $callable for each of them
+ * @param callable $callable
+ */
+ public function walk($callable) {
+ $this->retrieve_items();
+ array_walk($this->items, $callable);
+ }
+
+ /**
+ * Marks record or group of records as accessible (or not accessible)
+ *
+ * @param int|std_Class $identifier either record id of the item that needs to be set accessible
+ * @param bool $accessible whether to mark as accessible or not accessible (default true)
+ */
+ public function set_accessible($identifier, $accessible = true) {
+ if (is_object($identifier)) {
+ $identifier = (int)($identifier->{$this->idfield});
+ }
+ $this->init_items_access();
+ if (is_int($identifier)) {
+ $accessible = (int)(bool)$accessible;
+ if (!array_key_exists($identifier, $this->accessibleitems) ||
+ $this->accessibleitems[$identifier] != $accessible) {
+ $this->accessibleitems[$identifier] = $accessible;
+ $this->cachechangedaccessible;
+ }
+ } else {
+ throw new coding_exception('Argument $identifier must be either int or object');
+ }
+ }
+
+ /**
+ * Retrieves a course record (only fields id,visible,fullname,shortname,cacherev).
+ *
+ * This method is useful because it also caches results and preloads course context.
+ *
+ * @param int $courseid
+ */
+ public function get_course($courseid) {
+ global $DB;
+ if (!array_key_exists($courseid, $this->courses)) {
+ $ctxquery = context_helper::get_preload_record_columns_sql('ctx');
+ $sql = "SELECT c.id,c.visible,c.fullname,c.shortname,c.cacherev, $ctxquery
+ FROM {course} c JOIN {context} ctx ON ctx.contextlevel = ? AND ctx.instanceid=c.id
+ WHERE c.id = ?";
+ $params = array(CONTEXT_COURSE, $courseid);
+ $this->courses[$courseid] = $DB->get_record_sql($sql, $params);
+ context_helper::preload_from_record($this->courses[$courseid]);
+ }
+ return $this->courses[$courseid];
+ }
+
+ /**
+ * Ensures that we read the course access from the cache.
+ */
+ protected function init_course_access() {
+ if ($this->courseaccess === null) {
+ $this->courseaccess = cache::make('core', 'tagindexbuilder')->get('courseaccess') ?: [];
+ }
+ }
+
+ /**
+ * Ensures that we read the items access from the cache.
+ */
+ protected function init_items_access() {
+ if ($this->accessibleitems === null) {
+ $this->accessibleitems = cache::make('core', 'tagindexbuilder')->get($this->component.'__'.$this->itemtype) ?: [];
+ }
+ }
+
+ /**
+ * Checks if current user has access to the course
+ *
+ * This method calls global function {@link can_access_course} and caches results
+ *
+ * @param int $courseid
+ * @return bool
+ */
+ public function can_access_course($courseid) {
+ $this->init_course_access();
+ if (!array_key_exists($courseid, $this->courseaccess)) {
+ $this->courseaccess[$courseid] = can_access_course($this->get_course($courseid)) ? 1 : 0;
+ $this->cachechangedcourse = true;
+ }
+ return $this->courseaccess[$courseid];
+ }
+
+ /**
+ * Saves course/items caches if needed
+ */
+ protected function save_caches() {
+ if ($this->cachechangedcourse) {
+ cache::make('core', 'tagindexbuilder')->set('courseaccess', $this->courseaccess);
+ $this->cachechangedcourse = false;
+ }
+ if ($this->cachechangedaccessible) {
+ cache::make('core', 'tagindexbuilder')->set($this->component.'__'.$this->itemtype,
+ $this->accessibleitems);
+ $this->cachechangedaccessible = false;
+ }
+ }
+
+ /**
+ * Resets all course/items session caches - useful in unittests when we change users and enrolments.
+ */
+ public static function reset_caches() {
+ cache_helper::purge_by_event('resettagindexbuilder');
+ }
+}
