class BlockTranslation

class BlockTranslation extends Block {
    
    /**
     * {@inheritdoc}
     */
    public function query() {
        // Let the parent set the block table to use, but do not use the parent
        // query. Instead build a query so can use an inner join to the selected
        // block table.
        parent::query();
        $query = $this->select('i18n_blocks', 'i18n')
            ->fields('i18n')
            ->fields('b', [
            'bid',
            'module',
            'delta',
            'theme',
            'title',
        ]);
        $query->innerJoin($this->blockTable, 'b', 'b.module = i18n.module AND b.delta = i18n.delta');
        return $query;
    }
    
    /**
     * {@inheritdoc}
     */
    public function fields() {
        return [
            'bid' => $this->t('The block numeric identifier.'),
            'ibid' => $this->t('The i18n_blocks block numeric identifier.'),
            'module' => $this->t('The module providing the block.'),
            'delta' => $this->t("The block's delta."),
            'type' => $this->t('Block type'),
            'language' => $this->t('Language for this field.'),
            'theme' => $this->t('Which theme the block is placed in.'),
            'default_theme' => $this->t('The default theme.'),
            'title' => $this->t('Block title.'),
        ];
    }
    
    /**
     * {@inheritdoc}
     */
    public function prepareRow(Row $row) {
        $row->setSourceProperty('default_theme', $this->defaultTheme);
        return SourcePluginBase::prepareRow($row);
    }
    
    /**
     * {@inheritdoc}
     */
    public function getIds() {
        $ids = parent::getIds();
        $ids['module']['alias'] = 'b';
        $ids['delta']['alias'] = 'b';
        $ids['theme']['alias'] = 'b';
        $ids['language']['type'] = 'string';
        return $ids;
    }

}