EntityPreloader.php

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<?php

namespace Elgg;

use Elgg\Cache\EntityCache;
use Elgg\Database\Entities;

class EntityPreloader {
    
    const MAX_PRELOAD = 256;
    
    public $_callable_cache_checker;

    public $_callable_entity_loader;

    public function __construct(EntityCache $entity_cache) {
        $this->_callable_cache_checker = function ($guid) use ($entity_cache) {
            return $entity_cache->load($guid);
        };
        $this->_callable_entity_loader = function ($options) {
            return Entities::find($options);
        };
    }

    public function preload($objects, array $guid_properties) {
        $guids = $this->getGuidsToLoad($objects, $guid_properties);
        
        // If only 1 to load, not worth the overhead of elgg_get_entities(),
        // get_entity() will handle it later.
        if (count($guids) > 1) {
            call_user_func($this->_callable_entity_loader, [
                'guids' => $guids,
                'limit' => self::MAX_PRELOAD,
                'order_by' => false,
            ]);
        }
    }

    protected function getGuidsToLoad($objects, array $guid_properties) {
        if (!is_array($objects) || count($objects) < 2) {
            return [];
        }
        
        $preload_guids = [];
        foreach ($objects as $object) {
            if (is_object($object)) {
                foreach ($guid_properties as $property) {
                    if (empty($object->{$property})) {
                        continue;
                    }
                    
                    $guid = $object->{$property};
                    if ($guid && !call_user_func($this->_callable_cache_checker, $guid)) {
                        $preload_guids[] = $guid;
                    }
                }
            }
        }
        
        return array_unique($preload_guids);
    }
}