documentation/framework_2_indexer_2_handler_interface_8php_source.html

 <?php
 namespace Magento\Framework\Indexer;

 use Magento\Framework\App\ResourceConnection\SourceProviderInterface;

 interface HandlerInterface
 {
     public function prepareSql(SourceProviderInterface $source, $alias, $fieldInfo);
 }
Magento\Framework\Indexer\HandlerInterface
Definition: HandlerInterface.php:14

$source
$source
Definition: source.php:23

Magento\Framework\Indexer\HandlerInterface\prepareSql
prepareSql(SourceProviderInterface $source, $alias, $fieldInfo)

Magento\Framework\App\ResourceConnection\SourceProviderInterface
Definition: SourceProviderInterface.php:12

Magento\Framework\Indexer
Definition: AbstractProcessor.php:9

$alias
if(!trim($html)) $alias
Definition: details.phtml:20