PHP context_helper::delete_instance方法代码示例

/**
 * Remove a context record and any dependent entries,
 * removes context from static context cache too
 *
 * @deprecated since 2.2, use $context->delete_content() instead
 * @param int $contextlevel
 * @param int $instanceid
 * @param bool $deleterecord false means keep record for now
 * @return bool returns true or throws an exception
 */
function delete_context($contextlevel, $instanceid, $deleterecord = true)
{
    if ($deleterecord) {
        context_helper::delete_instance($contextlevel, $instanceid);
    } else {
        $classname = context_helper::get_class_for_level($contextlevel);
        if ($context = $classname::instance($instanceid, IGNORE_MISSING)) {
            $context->delete_content();
        }
    }
    return true;
}

/**
 * This function will handles the whole deletion process of a module. This includes calling
 * the modules delete_instance function, deleting files, events, grades, conditional data,
 * the data in the course_module and course_sections table and adding a module deletion
 * event to the DB.
 *
 * @param int $cmid the course module id
 * @since 2.5
 */
function course_delete_module($cmid)
{
    global $CFG, $DB;
    require_once $CFG->libdir . '/gradelib.php';
    require_once $CFG->dirroot . '/blog/lib.php';
    require_once $CFG->dirroot . '/calendar/lib.php';
    // Get the course module.
    if (!($cm = $DB->get_record('course_modules', array('id' => $cmid)))) {
        return true;
    }
    // Get the module context.
    $modcontext = context_module::instance($cm->id);
    // Get the course module name.
    $modulename = $DB->get_field('modules', 'name', array('id' => $cm->module), MUST_EXIST);
    // Get the file location of the delete_instance function for this module.
    $modlib = "{$CFG->dirroot}/mod/{$modulename}/lib.php";
    // Include the file required to call the delete_instance function for this module.
    if (file_exists($modlib)) {
        require_once $modlib;
    } else {
        throw new moodle_exception('cannotdeletemodulemissinglib', '', '', null, "Cannot delete this module as the file mod/{$modulename}/lib.php is missing.");
    }
    $deleteinstancefunction = $modulename . '_delete_instance';
    // Ensure the delete_instance function exists for this module.
    if (!function_exists($deleteinstancefunction)) {
        throw new moodle_exception('cannotdeletemodulemissingfunc', '', '', null, "Cannot delete this module as the function {$modulename}_delete_instance is missing in mod/{$modulename}/lib.php.");
    }
    // Call the delete_instance function, if it returns false throw an exception.
    if (!$deleteinstancefunction($cm->instance)) {
        throw new moodle_exception('cannotdeletemoduleinstance', '', '', null, "Cannot delete the module {$modulename} (instance).");
    }
    // Remove all module files in case modules forget to do that.
    $fs = get_file_storage();
    $fs->delete_area_files($modcontext->id);
    // Delete events from calendar.
    if ($events = $DB->get_records('event', array('instance' => $cm->instance, 'modulename' => $modulename))) {
        foreach ($events as $event) {
            $calendarevent = calendar_event::load($event->id);
            $calendarevent->delete();
        }
    }
    // Delete grade items, outcome items and grades attached to modules.
    if ($grade_items = grade_item::fetch_all(array('itemtype' => 'mod', 'itemmodule' => $modulename, 'iteminstance' => $cm->instance, 'courseid' => $cm->course))) {
        foreach ($grade_items as $grade_item) {
            $grade_item->delete('moddelete');
        }
    }
    // Delete completion and availability data; it is better to do this even if the
    // features are not turned on, in case they were turned on previously (these will be
    // very quick on an empty table).
    $DB->delete_records('course_modules_completion', array('coursemoduleid' => $cm->id));
    $DB->delete_records('course_modules_availability', array('coursemoduleid' => $cm->id));
    $DB->delete_records('course_modules_avail_fields', array('coursemoduleid' => $cm->id));
    $DB->delete_records('course_completion_criteria', array('moduleinstance' => $cm->id, 'criteriatype' => COMPLETION_CRITERIA_TYPE_ACTIVITY));
    // Delete the context.
    context_helper::delete_instance(CONTEXT_MODULE, $cm->id);
    // Delete the module from the course_modules table.
    $DB->delete_records('course_modules', array('id' => $cm->id));
    // Delete module from that section.
    if (!delete_mod_from_section($cm->id, $cm->section)) {
        throw new moodle_exception('cannotdeletemodulefromsection', '', '', null, "Cannot delete the module {$modulename} (instance) from section.");
    }
    // Trigger event for course module delete action.
    $event = \core\event\course_module_deleted::create(array('courseid' => $cm->course, 'context' => $modcontext, 'objectid' => $cm->id, 'other' => array('modulename' => $modulename, 'instanceid' => $cm->instance)));
    $event->add_record_snapshot('course_modules', $cm);
    $event->trigger();
    rebuild_course_cache($cm->course, true);
}

/**
 * Clear a course out completely, deleting all content but don't delete the course itself.
 *
 * This function does not verify any permissions.
 *
 * Please note this function also deletes all user enrolments,
 * enrolment instances and role assignments by default.
 *
 * $options:
 *  - 'keep_roles_and_enrolments' - false by default
 *  - 'keep_groups_and_groupings' - false by default
 *
 * @param int $courseid The id of the course that is being deleted
 * @param bool $showfeedback Whether to display notifications of each action the function performs.
 * @param array $options extra options
 * @return bool true if all the removals succeeded. false if there were any failures. If this
 *             method returns false, some of the removals will probably have succeeded, and others
 *             failed, but you have no way of knowing which.
 */
function remove_course_contents($courseid, $showfeedback = true, array $options = null)
{
    global $CFG, $DB, $OUTPUT;
    require_once $CFG->libdir . '/badgeslib.php';
    require_once $CFG->libdir . '/completionlib.php';
    require_once $CFG->libdir . '/questionlib.php';
    require_once $CFG->libdir . '/gradelib.php';
    require_once $CFG->dirroot . '/group/lib.php';
    require_once $CFG->dirroot . '/comment/lib.php';
    require_once $CFG->dirroot . '/rating/lib.php';
    require_once $CFG->dirroot . '/notes/lib.php';
    // Handle course badges.
    badges_handle_course_deletion($courseid);
    // NOTE: these concatenated strings are suboptimal, but it is just extra info...
    $strdeleted = get_string('deleted') . ' - ';
    // Some crazy wishlist of stuff we should skip during purging of course content.
    $options = (array) $options;
    $course = $DB->get_record('course', array('id' => $courseid), '*', MUST_EXIST);
    $coursecontext = context_course::instance($courseid);
    $fs = get_file_storage();
    // Delete course completion information, this has to be done before grades and enrols.
    $cc = new completion_info($course);
    $cc->clear_criteria();
    if ($showfeedback) {
        echo $OUTPUT->notification($strdeleted . get_string('completion', 'completion'), 'notifysuccess');
    }
    // Remove all data from gradebook - this needs to be done before course modules
    // because while deleting this information, the system may need to reference
    // the course modules that own the grades.
    remove_course_grades($courseid, $showfeedback);
    remove_grade_letters($coursecontext, $showfeedback);
    // Delete course blocks in any all child contexts,
    // they may depend on modules so delete them first.
    $childcontexts = $coursecontext->get_child_contexts();
    // Returns all subcontexts since 2.2.
    foreach ($childcontexts as $childcontext) {
        blocks_delete_all_for_context($childcontext->id);
    }
    unset($childcontexts);
    blocks_delete_all_for_context($coursecontext->id);
    if ($showfeedback) {
        echo $OUTPUT->notification($strdeleted . get_string('type_block_plural', 'plugin'), 'notifysuccess');
    }
    // Get the list of all modules that are properly installed.
    $allmodules = $DB->get_records_menu('modules', array(), '', 'name, id');
    // Delete every instance of every module,
    // this has to be done before deleting of course level stuff.
    $locations = core_component::get_plugin_list('mod');
    foreach ($locations as $modname => $moddir) {
        if ($modname === 'NEWMODULE') {
            continue;
        }
        if (array_key_exists($modname, $allmodules)) {
            $sql = "SELECT cm.*, m.id AS modinstance, m.name, '{$modname}' AS modname\n              FROM {" . $modname . "} m\n                   LEFT JOIN {course_modules} cm ON cm.instance = m.id AND cm.module = :moduleid\n             WHERE m.course = :courseid";
            $instances = $DB->get_records_sql($sql, array('courseid' => $course->id, 'modulename' => $modname, 'moduleid' => $allmodules[$modname]));
            include_once "{$moddir}/lib.php";
            // Shows php warning only if plugin defective.
            $moddelete = $modname . '_delete_instance';
            // Delete everything connected to an instance.
            $moddeletecourse = $modname . '_delete_course';
            // Delete other stray stuff (uncommon).
            if ($instances) {
                foreach ($instances as $cm) {
                    if ($cm->id) {
                        // Delete activity context questions and question categories.
                        question_delete_activity($cm, $showfeedback);
                        // Notify the competency subsystem.
                        \core_competency\api::hook_course_module_deleted($cm);
                    }
                    if (function_exists($moddelete)) {
                        // This purges all module data in related tables, extra user prefs, settings, etc.
                        $moddelete($cm->modinstance);
                    } else {
                        // NOTE: we should not allow installation of modules with missing delete support!
                        debugging("Defective module '{$modname}' detected when deleting course contents: missing function {$moddelete}()!");
                        $DB->delete_records($modname, array('id' => $cm->modinstance));
                    }
                    if ($cm->id) {
                        // Delete cm and its context - orphaned contexts are purged in cron in case of any race condition.
                        context_helper::delete_instance(CONTEXT_MODULE, $cm->id);
                        $DB->delete_records('course_modules', array('id' => $cm->id));
//.........这里部分代码省略.........

//.........这里部分代码省略.........
        $this->assertTrue($DB->record_exists('context', array('id'=>$context->id)));
        $this->assertEquals(0, $DB->count_records('block_instances', array('parentcontextid'=>$context->id)));


        // ====== $context->delete() =============================

        context_helper::reset_caches();
        $context = context_module::instance($testpages[4]);
        $this->assertTrue($DB->record_exists('context', array('id'=>$context->id)));
        $this->assertEquals(1, $DB->count_records('block_instances', array('parentcontextid'=>$context->id)));
        $bi = $DB->get_record('block_instances', array('parentcontextid'=>$context->id));
        $bicontext = context_block::instance($bi->id);
        $DB->delete_records('cache_flags', array());
        $context->delete(); // should delete also linked blocks
        $dirty = get_cache_flags('accesslib/dirtycontexts', time()-2);
        $this->assertTrue(isset($dirty[$context->path]));
        $this->assertFalse($DB->record_exists('context', array('id'=>$context->id)));
        $this->assertFalse($DB->record_exists('context', array('id'=>$bicontext->id)));
        $this->assertFalse($DB->record_exists('context', array('contextlevel'=>CONTEXT_MODULE, 'instanceid'=>$testpages[4])));
        $this->assertFalse($DB->record_exists('context', array('contextlevel'=>CONTEXT_BLOCK, 'instanceid'=>$bi->id)));
        $this->assertEquals(0, $DB->count_records('block_instances', array('parentcontextid'=>$context->id)));
        context_module::instance($testpages[4]);


        // ====== context_helper::delete_instance() =============================

        context_helper::reset_caches();
        $lastcourse = array_pop($testcourses);
        $this->assertTrue($DB->record_exists('context', array('contextlevel'=>CONTEXT_COURSE, 'instanceid'=>$lastcourse)));
        $coursecontext = context_course::instance($lastcourse);
        $this->assertEquals(context_inspection::test_context_cache_size(), 1);
        $this->assertFalse($coursecontext->instanceid == CONTEXT_COURSE);
        $DB->delete_records('cache_flags', array());
        context_helper::delete_instance(CONTEXT_COURSE, $lastcourse);
        $dirty = get_cache_flags('accesslib/dirtycontexts', time()-2);
        $this->assertTrue(isset($dirty[$coursecontext->path]));
        $this->assertEquals(context_inspection::test_context_cache_size(), 0);
        $this->assertFalse($DB->record_exists('context', array('contextlevel'=>CONTEXT_COURSE, 'instanceid'=>$lastcourse)));
        context_course::instance($lastcourse);


        // ======= context_helper::create_instances() ==========================

        $prevcount = $DB->count_records('context');
        $DB->delete_records('context', array('contextlevel'=>CONTEXT_BLOCK));
        context_helper::create_instances(null, true);
        $this->assertSame($DB->count_records('context'), $prevcount);
        $this->assertEquals($DB->count_records('context', array('depth'=>0)), 0);
        $this->assertEquals($DB->count_records('context', array('path'=>NULL)), 0);

        $DB->delete_records('context', array('contextlevel'=>CONTEXT_BLOCK));
        $DB->delete_records('block_instances', array());
        $prevcount = $DB->count_records('context');
        $DB->delete_records_select('context', 'contextlevel <> '.CONTEXT_SYSTEM);
        context_helper::create_instances(null, true);
        $this->assertSame($DB->count_records('context'), $prevcount);
        $this->assertEquals($DB->count_records('context', array('depth'=>0)), 0);
        $this->assertEquals($DB->count_records('context', array('path'=>NULL)), 0);


        // ======= context_helper::cleanup_instances() ==========================

        $lastcourse = $DB->get_field_sql("SELECT MAX(id) FROM {course}");
        $DB->delete_records('course', array('id'=>$lastcourse));
        $lastcategory = $DB->get_field_sql("SELECT MAX(id) FROM {course_categories}");
        $DB->delete_records('course_categories', array('id'=>$lastcategory));

/**
 * Remove a context record and any dependent entries,
 * removes context from static context cache too
 *
 * @deprecated since Moodle 2.2
 * @see context_helper::delete_instance() or context::delete_content()
 * @param int $contextlevel
 * @param int $instanceid
 * @param bool $deleterecord false means keep record for now
 * @return bool returns true or throws an exception
 */
function delete_context($contextlevel, $instanceid, $deleterecord = true)
{
    if ($deleterecord) {
        debugging('delete_context() is deprecated, please use context_helper::delete_instance() instead.', DEBUG_DEVELOPER);
        context_helper::delete_instance($contextlevel, $instanceid);
    } else {
        debugging('delete_context() is deprecated, please use $context->delete_content() instead.', DEBUG_DEVELOPER);
        $classname = context_helper::get_class_for_level($contextlevel);
        if ($context = $classname::instance($instanceid, IGNORE_MISSING)) {
            $context->delete_content();
        }
    }
    return true;
}

/**
 * Delete a block, and associated data.
 *
 * @param object $instance a row from the block_instances table
 * @param bool $nolongerused legacy parameter. Not used, but kept for backwards compatibility.
 * @param bool $skipblockstables for internal use only. Makes @see blocks_delete_all_for_context() more efficient.
 */
function blocks_delete_instance($instance, $nolongerused = false, $skipblockstables = false)
{
    global $DB;
    // Allow plugins to use this block before we completely delete it.
    if ($pluginsfunction = get_plugins_with_function('pre_block_delete')) {
        foreach ($pluginsfunction as $plugintype => $plugins) {
            foreach ($plugins as $pluginfunction) {
                $pluginfunction($instance);
            }
        }
    }
    if ($block = block_instance($instance->blockname, $instance)) {
        $block->instance_delete();
    }
    context_helper::delete_instance(CONTEXT_BLOCK, $instance->id);
    if (!$skipblockstables) {
        $DB->delete_records('block_positions', array('blockinstanceid' => $instance->id));
        $DB->delete_records('block_instances', array('id' => $instance->id));
        $DB->delete_records_list('user_preferences', 'name', array('block' . $instance->id . 'hidden', 'docked_block_instance_' . $instance->id));
    }
}

/**
 * Delete a block, and associated data.
 *
 * @param object $instance a row from the block_instances table
 * @param bool $nolongerused legacy parameter. Not used, but kept for backwards compatibility.
 * @param bool $skipblockstables for internal use only. Makes @see blocks_delete_all_for_context() more efficient.
 */
function blocks_delete_instance($instance, $nolongerused = false, $skipblockstables = false)
{
    global $DB;
    if ($block = block_instance($instance->blockname, $instance)) {
        $block->instance_delete();
    }
    context_helper::delete_instance(CONTEXT_BLOCK, $instance->id);
    if (!$skipblockstables) {
        $DB->delete_records('block_positions', array('blockinstanceid' => $instance->id));
        $DB->delete_records('block_instances', array('id' => $instance->id));
        $DB->delete_records_list('user_preferences', 'name', array('block' . $instance->id . 'hidden', 'docked_block_instance_' . $instance->id));
    }
}

/**
 * Add course module.
 *
 * The function does not check user capabilities.
 * The function creates course module, module instance, add the module to the correct section.
 * It also trigger common action that need to be done after adding/updating a module.
 *
 * @param object $moduleinfo the moudle data
 * @param object $course the course of the module
 * @param object $mform this is required by an existing hack to deal with files during MODULENAME_add_instance()
 * @return object the updated module info
 */
function add_moduleinfo($moduleinfo, $course, $mform = null)
{
    global $DB, $CFG;
    // Attempt to include module library before we make any changes to DB.
    include_modulelib($moduleinfo->modulename);
    $moduleinfo->course = $course->id;
    $moduleinfo = set_moduleinfo_defaults($moduleinfo);
    if (!empty($course->groupmodeforce) or !isset($moduleinfo->groupmode)) {
        $moduleinfo->groupmode = 0;
        // Do not set groupmode.
    }
    // First add course_module record because we need the context.
    $newcm = new stdClass();
    $newcm->course = $course->id;
    $newcm->module = $moduleinfo->module;
    $newcm->instance = 0;
    // Not known yet, will be updated later (this is similar to restore code).
    $newcm->visible = $moduleinfo->visible;
    $newcm->visibleold = $moduleinfo->visible;
    if (isset($moduleinfo->cmidnumber)) {
        $newcm->idnumber = $moduleinfo->cmidnumber;
    }
    $newcm->groupmode = $moduleinfo->groupmode;
    $newcm->groupingid = $moduleinfo->groupingid;
    $completion = new completion_info($course);
    if ($completion->is_enabled()) {
        $newcm->completion = $moduleinfo->completion;
        $newcm->completiongradeitemnumber = $moduleinfo->completiongradeitemnumber;
        $newcm->completionview = $moduleinfo->completionview;
        $newcm->completionexpected = $moduleinfo->completionexpected;
    }
    if (!empty($CFG->enableavailability)) {
        // This code is used both when submitting the form, which uses a long
        // name to avoid clashes, and by unit test code which uses the real
        // name in the table.
        $newcm->availability = null;
        if (property_exists($moduleinfo, 'availabilityconditionsjson')) {
            if ($moduleinfo->availabilityconditionsjson !== '') {
                $newcm->availability = $moduleinfo->availabilityconditionsjson;
            }
        } else {
            if (property_exists($moduleinfo, 'availability')) {
                $newcm->availability = $moduleinfo->availability;
            }
        }
    }
    if (isset($moduleinfo->showdescription)) {
        $newcm->showdescription = $moduleinfo->showdescription;
    } else {
        $newcm->showdescription = 0;
    }
    // From this point we make database changes, so start transaction.
    $transaction = $DB->start_delegated_transaction();
    if (!($moduleinfo->coursemodule = add_course_module($newcm))) {
        print_error('cannotaddcoursemodule');
    }
    if (plugin_supports('mod', $moduleinfo->modulename, FEATURE_MOD_INTRO, true) && isset($moduleinfo->introeditor)) {
        $introeditor = $moduleinfo->introeditor;
        unset($moduleinfo->introeditor);
        $moduleinfo->intro = $introeditor['text'];
        $moduleinfo->introformat = $introeditor['format'];
    }
    $addinstancefunction = $moduleinfo->modulename . "_add_instance";
    try {
        $returnfromfunc = $addinstancefunction($moduleinfo, $mform);
    } catch (moodle_exception $e) {
        $returnfromfunc = $e;
    }
    if (!$returnfromfunc or !is_number($returnfromfunc)) {
        // Undo everything we can. This is not necessary for databases which
        // support transactions, but improves consistency for other databases.
        $modcontext = context_module::instance($moduleinfo->coursemodule);
        context_helper::delete_instance(CONTEXT_MODULE, $moduleinfo->coursemodule);
        $DB->delete_records('course_modules', array('id' => $moduleinfo->coursemodule));
        if ($e instanceof moodle_exception) {
            throw $e;
        } else {
            if (!is_number($returnfromfunc)) {
                print_error('invalidfunction', '', course_get_url($course, $moduleinfo->section));
            } else {
                print_error('cannotaddnewmodule', '', course_get_url($course, $moduleinfo->section), $moduleinfo->modulename);
            }
        }
    }
    $moduleinfo->instance = $returnfromfunc;
    $DB->set_field('course_modules', 'instance', $returnfromfunc, array('id' => $moduleinfo->coursemodule));
    // Update embedded links and save files.
    $modcontext = context_module::instance($moduleinfo->coursemodule);
//.........这里部分代码省略.........

/**
 * Clear a course out completely, deleting all content
 * but don't delete the course itself.
 * This function does not verify any permissions.
 *
 * Please note this function also deletes all user enrolments,
 * enrolment instances and role assignments by default.
 *
 * $options:
 *  - 'keep_roles_and_enrolments' - false by default
 *  - 'keep_groups_and_groupings' - false by default
 *
 * @param int $courseid The id of the course that is being deleted
 * @param bool $showfeedback Whether to display notifications of each action the function performs.
 * @param array $options extra options
 * @return bool true if all the removals succeeded. false if there were any failures. If this
 *             method returns false, some of the removals will probably have succeeded, and others
 *             failed, but you have no way of knowing which.
 */
function remove_course_contents($courseid, $showfeedback = true, array $options = null)
{
    global $CFG, $DB, $OUTPUT;
    require_once $CFG->libdir . '/completionlib.php';
    require_once $CFG->libdir . '/questionlib.php';
    require_once $CFG->libdir . '/gradelib.php';
    require_once $CFG->dirroot . '/group/lib.php';
    require_once $CFG->dirroot . '/tag/coursetagslib.php';
    require_once $CFG->dirroot . '/comment/lib.php';
    require_once $CFG->dirroot . '/rating/lib.php';
    // NOTE: these concatenated strings are suboptimal, but it is just extra info...
    $strdeleted = get_string('deleted') . ' - ';
    // Some crazy wishlist of stuff we should skip during purging of course content
    $options = (array) $options;
    $course = $DB->get_record('course', array('id' => $courseid), '*', MUST_EXIST);
    $coursecontext = context_course::instance($courseid);
    $fs = get_file_storage();
    // Delete course completion information, this has to be done before grades and enrols
    $cc = new completion_info($course);
    $cc->clear_criteria();
    if ($showfeedback) {
        echo $OUTPUT->notification($strdeleted . get_string('completion', 'completion'), 'notifysuccess');
    }
    // Remove all data from gradebook - this needs to be done before course modules
    // because while deleting this information, the system may need to reference
    // the course modules that own the grades.
    remove_course_grades($courseid, $showfeedback);
    remove_grade_letters($coursecontext, $showfeedback);
    // Delete course blocks in any all child contexts,
    // they may depend on modules so delete them first
    $childcontexts = $coursecontext->get_child_contexts();
    // returns all subcontexts since 2.2
    foreach ($childcontexts as $childcontext) {
        blocks_delete_all_for_context($childcontext->id);
    }
    unset($childcontexts);
    blocks_delete_all_for_context($coursecontext->id);
    if ($showfeedback) {
        echo $OUTPUT->notification($strdeleted . get_string('type_block_plural', 'plugin'), 'notifysuccess');
    }
    // Delete every instance of every module,
    // this has to be done before deleting of course level stuff
    $locations = get_plugin_list('mod');
    foreach ($locations as $modname => $moddir) {
        if ($modname === 'NEWMODULE') {
            continue;
        }
        if ($module = $DB->get_record('modules', array('name' => $modname))) {
            include_once "{$moddir}/lib.php";
            // Shows php warning only if plugin defective
            $moddelete = $modname . '_delete_instance';
            // Delete everything connected to an instance
            $moddeletecourse = $modname . '_delete_course';
            // Delete other stray stuff (uncommon)
            if ($instances = $DB->get_records($modname, array('course' => $course->id))) {
                foreach ($instances as $instance) {
                    if ($cm = get_coursemodule_from_instance($modname, $instance->id, $course->id)) {
                        /// Delete activity context questions and question categories
                        question_delete_activity($cm, $showfeedback);
                    }
                    if (function_exists($moddelete)) {
                        // This purges all module data in related tables, extra user prefs, settings, etc.
                        $moddelete($instance->id);
                    } else {
                        // NOTE: we should not allow installation of modules with missing delete support!
                        debugging("Defective module '{$modname}' detected when deleting course contents: missing function {$moddelete}()!");
                        $DB->delete_records($modname, array('id' => $instance->id));
                    }
                    if ($cm) {
                        // Delete cm and its context - orphaned contexts are purged in cron in case of any race condition
                        context_helper::delete_instance(CONTEXT_MODULE, $cm->id);
                        $DB->delete_records('course_modules', array('id' => $cm->id));
                    }
                }
            }
            if (function_exists($moddeletecourse)) {
                // Execute ptional course cleanup callback
                $moddeletecourse($course, $showfeedback);
            }
            if ($instances and $showfeedback) {
                echo $OUTPUT->notification($strdeleted . get_string('pluginname', $modname), 'notifysuccess');
//.........这里部分代码省略.........

/**
 * Add course module.
 *
 * The function does not check user capabilities.
 * The function creates course module, module instance, add the module to the correct section.
 * It also trigger common action that need to be done after adding/updating a module.
 *
 * @param object $moduleinfo the moudle data
 * @param object $course the course of the module
 * @param object $mform this is required by an existing hack to deal with files during MODULENAME_add_instance()
 * @return object the updated module info
 */
function add_moduleinfo($moduleinfo, $course, $mform = null)
{
    global $DB, $CFG;
    // Attempt to include module library before we make any changes to DB.
    include_modulelib($moduleinfo->modulename);
    $moduleinfo->course = $course->id;
    $moduleinfo = set_moduleinfo_defaults($moduleinfo);
    if (!empty($course->groupmodeforce) or !isset($moduleinfo->groupmode)) {
        $moduleinfo->groupmode = 0;
        // Do not set groupmode.
    }
    // First add course_module record because we need the context.
    $newcm = new stdClass();
    $newcm->course = $course->id;
    $newcm->module = $moduleinfo->module;
    $newcm->instance = 0;
    // Not known yet, will be updated later (this is similar to restore code).
    $newcm->visible = $moduleinfo->visible;
    $newcm->visibleold = $moduleinfo->visible;
    if (isset($moduleinfo->cmidnumber)) {
        $newcm->idnumber = $moduleinfo->cmidnumber;
    }
    $newcm->groupmode = $moduleinfo->groupmode;
    $newcm->groupingid = $moduleinfo->groupingid;
    $newcm->groupmembersonly = $moduleinfo->groupmembersonly;
    $completion = new completion_info($course);
    if ($completion->is_enabled()) {
        $newcm->completion = $moduleinfo->completion;
        $newcm->completiongradeitemnumber = $moduleinfo->completiongradeitemnumber;
        $newcm->completionview = $moduleinfo->completionview;
        $newcm->completionexpected = $moduleinfo->completionexpected;
    }
    if (!empty($CFG->enableavailability)) {
        $newcm->availablefrom = $moduleinfo->availablefrom;
        $newcm->availableuntil = $moduleinfo->availableuntil;
        $newcm->showavailability = $moduleinfo->showavailability;
    }
    if (isset($moduleinfo->showdescription)) {
        $newcm->showdescription = $moduleinfo->showdescription;
    } else {
        $newcm->showdescription = 0;
    }
    if (!($moduleinfo->coursemodule = add_course_module($newcm))) {
        print_error('cannotaddcoursemodule');
    }
    if (plugin_supports('mod', $moduleinfo->modulename, FEATURE_MOD_INTRO, true) && isset($moduleinfo->introeditor)) {
        $introeditor = $moduleinfo->introeditor;
        unset($moduleinfo->introeditor);
        $moduleinfo->intro = $introeditor['text'];
        $moduleinfo->introformat = $introeditor['format'];
    }
    $addinstancefunction = $moduleinfo->modulename . "_add_instance";
    $returnfromfunc = $addinstancefunction($moduleinfo, $mform);
    if (!$returnfromfunc or !is_number($returnfromfunc)) {
        // Undo everything we can.
        $modcontext = context_module::instance($moduleinfo->coursemodule);
        context_helper::delete_instance(CONTEXT_MODULE, $moduleinfo->coursemodule);
        $DB->delete_records('course_modules', array('id' => $moduleinfo->coursemodule));
        if (!is_number($returnfromfunc)) {
            print_error('invalidfunction', '', course_get_url($course, $moduleinfo->section));
        } else {
            print_error('cannotaddnewmodule', '', course_get_url($course, $moduleinfo->section), $moduleinfo->modulename);
        }
    }
    $moduleinfo->instance = $returnfromfunc;
    $DB->set_field('course_modules', 'instance', $returnfromfunc, array('id' => $moduleinfo->coursemodule));
    // Update embedded links and save files.
    $modcontext = context_module::instance($moduleinfo->coursemodule);
    if (!empty($introeditor)) {
        $moduleinfo->intro = file_save_draft_area_files($introeditor['itemid'], $modcontext->id, 'mod_' . $moduleinfo->modulename, 'intro', 0, array('subdirs' => true), $introeditor['text']);
        $DB->set_field($moduleinfo->modulename, 'intro', $moduleinfo->intro, array('id' => $moduleinfo->instance));
    }
    // Course_modules and course_sections each contain a reference to each other.
    // So we have to update one of them twice.
    $sectionid = course_add_cm_to_section($course, $moduleinfo->coursemodule, $moduleinfo->section);
    // Set up conditions.
    if ($CFG->enableavailability) {
        condition_info::update_cm_from_form((object) array('id' => $moduleinfo->coursemodule), $moduleinfo, false);
    }
    // Trigger event based on the action we did.
    $event = \core\event\course_module_created::create(array('courseid' => $course->id, 'context' => $modcontext, 'objectid' => $moduleinfo->coursemodule, 'other' => array('modulename' => $moduleinfo->modulename, 'name' => $moduleinfo->name, 'instanceid' => $moduleinfo->instance)));
    $event->trigger();
    add_to_log($course->id, $moduleinfo->modulename, "add", "view.php?id={$moduleinfo->coursemodule}", "{$moduleinfo->instance}", $moduleinfo->coursemodule);
    $moduleinfo = edit_module_post_actions($moduleinfo, $course);
    return $moduleinfo;
}

//.........这里部分代码省略.........
     context_helper::reset_caches();
     $context = context_module::instance($testpages[3]);
     $this->assertTrue($DB->record_exists('context', array('id' => $context->id)));
     $this->assertEqual(1, $DB->count_records('block_instances', array('parentcontextid' => $context->id)));
     $context->delete_content();
     $this->assertTrue($DB->record_exists('context', array('id' => $context->id)));
     $this->assertEqual(0, $DB->count_records('block_instances', array('parentcontextid' => $context->id)));
     // ====== $context->delete() =============================
     context_helper::reset_caches();
     $context = context_module::instance($testpages[4]);
     $this->assertTrue($DB->record_exists('context', array('id' => $context->id)));
     $this->assertEqual(1, $DB->count_records('block_instances', array('parentcontextid' => $context->id)));
     $bi = $DB->get_record('block_instances', array('parentcontextid' => $context->id));
     $bicontext = context_block::instance($bi->id);
     $DB->delete_records('cache_flags', array());
     $context->delete();
     // should delete also linked blocks
     $dirty = get_cache_flags('accesslib/dirtycontexts', time() - 2);
     $this->assertTrue(isset($dirty[$context->path]));
     $this->assertFalse($DB->record_exists('context', array('id' => $context->id)));
     $this->assertFalse($DB->record_exists('context', array('id' => $bicontext->id)));
     $this->assertFalse($DB->record_exists('context', array('contextlevel' => CONTEXT_MODULE, 'instanceid' => $testpages[4])));
     $this->assertFalse($DB->record_exists('context', array('contextlevel' => CONTEXT_BLOCK, 'instanceid' => $bi->id)));
     $this->assertEqual(0, $DB->count_records('block_instances', array('parentcontextid' => $context->id)));
     context_module::instance($testpages[4]);
     // ====== context_helper::delete_instance() =============================
     context_helper::reset_caches();
     $lastcourse = array_pop($testcourses);
     $this->assertTrue($DB->record_exists('context', array('contextlevel' => CONTEXT_COURSE, 'instanceid' => $lastcourse)));
     $coursecontext = context_course::instance($lastcourse);
     $this->assertEqual(context_inspection::test_context_cache_size(), 1);
     $this->assertFalse($coursecontext->instanceid == CONTEXT_COURSE);
     $DB->delete_records('cache_flags', array());
     context_helper::delete_instance(CONTEXT_COURSE, $lastcourse);
     $dirty = get_cache_flags('accesslib/dirtycontexts', time() - 2);
     $this->assertTrue(isset($dirty[$coursecontext->path]));
     $this->assertEqual(context_inspection::test_context_cache_size(), 0);
     $this->assertFalse($DB->record_exists('context', array('contextlevel' => CONTEXT_COURSE, 'instanceid' => $lastcourse)));
     context_course::instance($lastcourse);
     // ======= context_helper::create_instances() ==========================
     $prevcount = $DB->count_records('context');
     $DB->delete_records('context', array('contextlevel' => CONTEXT_BLOCK));
     context_helper::create_instances(null, true);
     $this->assertIdentical($DB->count_records('context'), $prevcount);
     $this->assertEqual($DB->count_records('context', array('depth' => 0)), 0);
     $this->assertEqual($DB->count_records('context', array('path' => NULL)), 0);
     $DB->delete_records('context', array('contextlevel' => CONTEXT_BLOCK));
     $DB->delete_records('block_instances', array());
     $prevcount = $DB->count_records('context');
     $DB->delete_records_select('context', 'contextlevel <> ' . CONTEXT_SYSTEM);
     context_helper::create_instances(null, true);
     $this->assertIdentical($DB->count_records('context'), $prevcount);
     $this->assertEqual($DB->count_records('context', array('depth' => 0)), 0);
     $this->assertEqual($DB->count_records('context', array('path' => NULL)), 0);
     // ======= context_helper::cleanup_instances() ==========================
     $lastcourse = $DB->get_field_sql("SELECT MAX(id) FROM {course}");
     $DB->delete_records('course', array('id' => $lastcourse));
     $lastcategory = $DB->get_field_sql("SELECT MAX(id) FROM {course_categories}");
     $DB->delete_records('course_categories', array('id' => $lastcategory));
     $lastuser = $DB->get_field_sql("SELECT MAX(id) FROM {user} WHERE deleted=0");
     $DB->delete_records('user', array('id' => $lastuser));
     $DB->delete_records('block_instances', array('parentcontextid' => $frontpagepagecontext->id));
     $DB->delete_records('course_modules', array('id' => $frontpagepagecontext->instanceid));
     context_helper::cleanup_instances();
     $count = 1;
     //system

//.........这里部分代码省略.........
        // Main savepoint reached
        upgrade_main_savepoint(true, 2011091600.01);
    }
    if ($oldversion < 2011092800.01) {
        // Check for potential missing columns in the grade_items_history
        $table = new xmldb_table('grade_items_history');
        $field = new xmldb_field('display', XMLDB_TYPE_INTEGER, '10', null, XMLDB_NOTNULL, null, 0, 'sortorder');
        if (!$dbman->field_exists($table, $field)) {
            $dbman->add_field($table, $field);
        }
        $field = new xmldb_field('decimals', XMLDB_TYPE_INTEGER, '1', XMLDB_UNSIGNED, null, null, null, 'display');
        if (!$dbman->field_exists($table, $field)) {
            $dbman->add_field($table, $field);
        } else {
            //check that the grade_items_history.decimals allows nulls
            //Somehow some Moodle databases have this column marked as "not null"
            $columns = $DB->get_columns('grade_items_history');
            if (array_key_exists('display', $columns) && !empty($columns['display']->not_null)) {
                $dbman->change_field_notnull($table, $field);
            }
        }
        // Main savepoint reached
        upgrade_main_savepoint(true, 2011092800.01);
    }
    if ($oldversion < 2011092800.02) {
        // Check for potential missing columns in the grade_categories_history
        $table = new xmldb_table('grade_categories_history');
        $field = new xmldb_field('hidden', XMLDB_TYPE_INTEGER, '1', XMLDB_UNSIGNED, XMLDB_NOTNULL, null, 0, 'timemodified');
        if (!$dbman->field_exists($table, $field)) {
            $dbman->add_field($table, $field);
        }
        // Main savepoint reached
        upgrade_main_savepoint(true, 2011092800.02);
    }
    if ($oldversion < 2011092800.03) {
        // Check for potential missing columns in the grade_outcomes_history
        $table = new xmldb_table('grade_outcomes_history');
        $field = new xmldb_field('descriptionformat', XMLDB_TYPE_INTEGER, '2', XMLDB_UNSIGNED, XMLDB_NOTNULL, null, 0, 'description');
        if (!$dbman->field_exists($table, $field)) {
            $dbman->add_field($table, $field);
        }
        // Main savepoint reached
        upgrade_main_savepoint(true, 2011092800.03);
    }
    if ($oldversion < 2011100700.02) {
        // Define field idnumber to be added to course_categories
        $table = new xmldb_table('course_categories');
        $field = new xmldb_field('idnumber', XMLDB_TYPE_CHAR, '100', null, null, null, null, 'name');
        // Conditionally launch add field idnumber
        if (!$dbman->field_exists($table, $field)) {
            $dbman->add_field($table, $field);
        }
        // Main savepoint reached
        upgrade_main_savepoint(true, 2011100700.02);
    }
    if ($oldversion < 2011101200.01) {
        // The conditional availability date system used to rely on dates being
        // set to 23:59:59 for the end date, but now that exact times are
        // supported, it uses midnight on the following day.
        // The query is restricted on 'time mod 10 = 9' in order that
        // it is safe to run this upgrade twice if something goes wrong.
        $DB->execute('UPDATE {course_modules} SET availableuntil = availableuntil + 1 ' . 'WHERE availableuntil > 0 AND ' . $DB->sql_modulo('availableuntil', 10) . ' = 9');
        // Because availableuntil is stored in modinfo, we need to clear modinfo
        // for all courses.
        rebuild_course_cache(0, true);
        // Main savepoint reached
        upgrade_main_savepoint(true, 2011101200.01);
    }
    if ($oldversion < 2011101900.02) {
        // remove unused setting
        unset_config('enablehtmlpurifier');
        upgrade_main_savepoint(true, 2011101900.02);
    }
    if ($oldversion < 2011102700.01) {
        // purge everything related to abandoned experimental global search
        // unset setting - this disables it in case user does not delete the dirs
        unset_config('enableglobalsearch');
        // Delete block, instances and db table
        $table = new xmldb_table('block_search_documents');
        if ($dbman->table_exists($table)) {
            $instances = $DB->get_records('block_instances', array('blockname' => 'search'));
            foreach ($instances as $instance) {
                context_helper::delete_instance(CONTEXT_BLOCK, $instance->id);
                $DB->delete_records('block_positions', array('blockinstanceid' => $instance->id));
                $DB->delete_records('block_instances', array('id' => $instance->id));
            }
            $DB->delete_records('block', array('name' => 'search'));
            $dbman->drop_table($table);
        }
        // purge all settings used by the search block
        $like = $DB->sql_like('name', '?', true, true, false, '|');
        $params = array($DB->sql_like_escape('block_search_', '|') . '%', $DB->sql_like_escape('search_in_', '|') . '%');
        $settings = $DB->get_records_select('config', "{$like} OR {$like}", $params);
        foreach ($settings as $setting) {
            unset_config($setting->name);
        }
        upgrade_main_savepoint(true, 2011102700.01);
    }
    return true;
}

/**
 * This function will handle the whole deletion process of a module. This includes calling
 * the modules delete_instance function, deleting files, events, grades, conditional data,
 * the data in the course_module and course_sections table and adding a module deletion
 * event to the DB.
 *
 * @param int $cmid the course module id
 * @param bool $async whether or not to try to delete the module using an adhoc task. Async also depends on a plugin hook.
 * @throws moodle_exception
 * @since Moodle 2.5
 */
function course_delete_module($cmid, $async = false)
{
    // Check the 'course_module_background_deletion_recommended' hook first.
    // Only use asynchronous deletion if at least one plugin returns true and if async deletion has been requested.
    // Both are checked because plugins should not be allowed to dictate the deletion behaviour, only support/decline it.
    // It's up to plugins to handle things like whether or not they are enabled.
    if ($async && ($pluginsfunction = get_plugins_with_function('course_module_background_deletion_recommended'))) {
        foreach ($pluginsfunction as $plugintype => $plugins) {
            foreach ($plugins as $pluginfunction) {
                if ($pluginfunction()) {
                    return course_module_flag_for_async_deletion($cmid);
                }
            }
        }
    }
    global $CFG, $DB;
    require_once $CFG->libdir . '/gradelib.php';
    require_once $CFG->libdir . '/questionlib.php';
    require_once $CFG->dirroot . '/blog/lib.php';
    require_once $CFG->dirroot . '/calendar/lib.php';
    // Get the course module.
    if (!($cm = $DB->get_record('course_modules', array('id' => $cmid)))) {
        return true;
    }
    // Get the module context.
    $modcontext = context_module::instance($cm->id);
    // Get the course module name.
    $modulename = $DB->get_field('modules', 'name', array('id' => $cm->module), MUST_EXIST);
    // Get the file location of the delete_instance function for this module.
    $modlib = "{$CFG->dirroot}/mod/{$modulename}/lib.php";
    // Include the file required to call the delete_instance function for this module.
    if (file_exists($modlib)) {
        require_once $modlib;
    } else {
        throw new moodle_exception('cannotdeletemodulemissinglib', '', '', null, "Cannot delete this module as the file mod/{$modulename}/lib.php is missing.");
    }
    $deleteinstancefunction = $modulename . '_delete_instance';
    // Ensure the delete_instance function exists for this module.
    if (!function_exists($deleteinstancefunction)) {
        throw new moodle_exception('cannotdeletemodulemissingfunc', '', '', null, "Cannot delete this module as the function {$modulename}_delete_instance is missing in mod/{$modulename}/lib.php.");
    }
    // Allow plugins to use this course module before we completely delete it.
    if ($pluginsfunction = get_plugins_with_function('pre_course_module_delete')) {
        foreach ($pluginsfunction as $plugintype => $plugins) {
            foreach ($plugins as $pluginfunction) {
                $pluginfunction($cm);
            }
        }
    }
    // Delete activity context questions and question categories.
    question_delete_activity($cm);
    // Call the delete_instance function, if it returns false throw an exception.
    if (!$deleteinstancefunction($cm->instance)) {
        throw new moodle_exception('cannotdeletemoduleinstance', '', '', null, "Cannot delete the module {$modulename} (instance).");
    }
    // Remove all module files in case modules forget to do that.
    $fs = get_file_storage();
    $fs->delete_area_files($modcontext->id);
    // Delete events from calendar.
    if ($events = $DB->get_records('event', array('instance' => $cm->instance, 'modulename' => $modulename))) {
        foreach ($events as $event) {
            $calendarevent = calendar_event::load($event->id);
            $calendarevent->delete();
        }
    }
    // Delete grade items, outcome items and grades attached to modules.
    if ($grade_items = grade_item::fetch_all(array('itemtype' => 'mod', 'itemmodule' => $modulename, 'iteminstance' => $cm->instance, 'courseid' => $cm->course))) {
        foreach ($grade_items as $grade_item) {
            $grade_item->delete('moddelete');
        }
    }
    // Delete completion and availability data; it is better to do this even if the
    // features are not turned on, in case they were turned on previously (these will be
    // very quick on an empty table).
    $DB->delete_records('course_modules_completion', array('coursemoduleid' => $cm->id));
    $DB->delete_records('course_completion_criteria', array('moduleinstance' => $cm->id, 'course' => $cm->course, 'criteriatype' => COMPLETION_CRITERIA_TYPE_ACTIVITY));
    // Delete all tag instances associated with the instance of this module.
    core_tag_tag::delete_instances('mod_' . $modulename, null, $modcontext->id);
    core_tag_tag::remove_all_item_tags('core', 'course_modules', $cm->id);
    // Notify the competency subsystem.
    \core_competency\api::hook_course_module_deleted($cm);
    // Delete the context.
    context_helper::delete_instance(CONTEXT_MODULE, $cm->id);
    // Delete the module from the course_modules table.
    $DB->delete_records('course_modules', array('id' => $cm->id));
    // Delete module from that section.
    if (!delete_mod_from_section($cm->id, $cm->section)) {
        throw new moodle_exception('cannotdeletemodulefromsection', '', '', null, "Cannot delete the module {$modulename} (instance) from section.");
    }
//.........这里部分代码省略.........

 /**
  * Pre-uninstall hook.
  *
  * This is intended for disabling of plugin, some DB table purging, etc.
  *
  * NOTE: to be called from uninstall_plugin() only.
  * @private
  */
 public function uninstall_cleanup()
 {
     global $DB, $CFG;
     if (!($module = $DB->get_record('modules', array('name' => $this->name)))) {
         parent::uninstall_cleanup();
         return;
     }
     // Delete all the relevant instances from all course sections.
     if ($coursemods = $DB->get_records('course_modules', array('module' => $module->id))) {
         foreach ($coursemods as $coursemod) {
             // Do not verify results, there is not much we can do anyway.
             delete_mod_from_section($coursemod->id, $coursemod->section);
         }
     }
     // Increment course.cacherev for courses that used this module.
     // This will force cache rebuilding on the next request.
     increment_revision_number('course', 'cacherev', "id IN (SELECT DISTINCT course\n                      FROM {course_modules}\n                     WHERE module=?)", array($module->id));
     // Delete all the course module records.
     $DB->delete_records('course_modules', array('module' => $module->id));
     // Delete module contexts.
     if ($coursemods) {
         foreach ($coursemods as $coursemod) {
             \context_helper::delete_instance(CONTEXT_MODULE, $coursemod->id);
         }
     }
     // Delete the module entry itself.
     $DB->delete_records('modules', array('name' => $module->name));
     // Cleanup the gradebook.
     require_once $CFG->libdir . '/gradelib.php';
     grade_uninstalled_module($module->name);
     // Do not look for legacy $module->name . '_uninstall any more,
     // they should have migrated to db/uninstall.php by now.
     parent::uninstall_cleanup();
 }