BlockManager::getBlockClasses PHP Method

    public function getBlockClasses()
    {
        $classes = ArrayLib::valuekey(ClassInfo::subclassesFor('Block'));
        array_shift($classes);
        foreach ($classes as $k => $v) {
            $classes[$k] = singleton($k)->singular_name();
        }
        $themeConfig = $this->getThemeConfig();
        if (isset($themeConfig['use_default_blocks']) && !$themeConfig['use_default_blocks']) {
            unset($classes['ContentBlock']);
        } else {
            if (!$this->config()->use_default_blocks) {
                unset($classes['ContentBlock']);
            }
        }
        $disabledArr = Config::inst()->get('BlockManager', 'disabled_blocks') ? Config::inst()->get('BlockManager', 'disabled_blocks') : array();
        if (isset($themeConfig['disabled_blocks'])) {
            $disabledArr = array_merge($disabledArr, $themeConfig['disabled_blocks']);
        }
        if (count($disabledArr)) {
            foreach ($disabledArr as $k => $v) {
                unset($classes[$v]);
            }
        }
        return $classes;
    }

 public function getCMSFields()
 {
     Requirements::add_i18n_javascript(BLOCKS_DIR . '/javascript/lang');
     // this line is a temporary patch until I can work out why this dependency isn't being
     // loaded in some cases...
     if (!$this->blockManager) {
         $this->blockManager = singleton('BlockManager');
     }
     $fields = parent::getCMSFields();
     // ClassNmae - block type/class field
     $classes = $this->blockManager->getBlockClasses();
     $fields->addFieldToTab('Root.Main', DropdownField::create('ClassName', 'Block Type', $classes)->addExtraClass('block-type'), 'Title');
     // BlockArea - display areas field if on page edit controller
     if (Controller::curr()->class == 'CMSPageEditController') {
         $currentPage = Controller::curr()->currentPage();
         $fields->addFieldToTab('Root.Main', DropdownField::create('ManyMany[BlockArea]', 'BlockArea', $this->blockManager->getAreasForPageType($currentPage->ClassName))->setHasEmptyDefault(true)->setRightTitle($currentPage->areasPreviewButton()), 'ClassName');
     }
     $fields->removeFieldFromTab('Root', 'BlockSets');
     $fields->removeFieldFromTab('Root', 'Pages');
     // legacy fields, will be removed in later release
     $fields->removeByName('Weight');
     $fields->removeByName('Area');
     $fields->removeByName('Published');
     if ($this->blockManager->getUseExtraCSSClasses()) {
         $fields->addFieldToTab('Root.Main', $fields->dataFieldByName('ExtraCSSClasses'), 'Title');
     } else {
         $fields->removeByName('ExtraCSSClasses');
     }
     // Viewer groups
     $fields->removeFieldFromTab('Root', 'ViewerGroups');
     $groupsMap = Group::get()->map('ID', 'Breadcrumbs')->toArray();
     asort($groupsMap);
     $viewersOptionsField = new OptionsetField("CanViewType", _t('SiteTree.ACCESSHEADER', "Who can view this page?"));
     $viewerGroupsField = ListboxField::create("ViewerGroups", _t('SiteTree.VIEWERGROUPS', "Viewer Groups"))->setMultiple(true)->setSource($groupsMap)->setAttribute('data-placeholder', _t('SiteTree.GroupPlaceholder', 'Click to select group'));
     $viewersOptionsSource = array();
     $viewersOptionsSource["Anyone"] = _t('SiteTree.ACCESSANYONE', "Anyone");
     $viewersOptionsSource["LoggedInUsers"] = _t('SiteTree.ACCESSLOGGEDIN', "Logged-in users");
     $viewersOptionsSource["OnlyTheseUsers"] = _t('SiteTree.ACCESSONLYTHESE', "Only these people (choose from list)");
     $viewersOptionsField->setSource($viewersOptionsSource)->setValue("Anyone");
     $fields->addFieldsToTab('Root.ViewerGroups', array($viewersOptionsField, $viewerGroupsField));
     // Disabled for now, until we can list ALL pages this block is applied to (inc via sets)
     // As otherwise it could be misleading
     // Show a GridField (list only) with pages which this block is used on
     // $fields->removeFieldFromTab('Root.Pages', 'Pages');
     // $fields->addFieldsToTab('Root.Pages',
     // 		new GridField(
     // 				'Pages',
     // 				'Used on pages',
     // 				$this->Pages(),
     // 				$gconf = GridFieldConfig_Base::create()));
     // enhance gridfield with edit links to pages if GFEditSiteTreeItemButtons is available
     // a GFRecordEditor (default) combined with BetterButtons already gives the possibility to
     // edit versioned records (Pages), but STbutton loads them in their own interface instead
     // of GFdetailform
     // if(class_exists('GridFieldEditSiteTreeItemButton')){
     // 	$gconf->addComponent(new GridFieldEditSiteTreeItemButton());
     // }
     return $fields;
 }