midcom_helper__dbfactory

Complexity

Total Complexity

48

Size/Duplication

Total Lines	292
Duplicated Lines	0 %

Test Coverage

Coverage

91.2%

Importance

Changes	1
Bugs	0	Features	0

16 Methods

Rating	Name	Duplication	Size	Complexity
A	new_collector()	0	3	1
A	__construct()	0	5	1
A	get_object_by_guid()	0	14	4
A	convert_midgard_to_midcom()	0	4	1
A	get_parent_data()	0	7	2
A	get_parent_data_cached()	0	20	5
A	get_parent_data_uncached()	0	13	4
A	get_data_from_guid()	0	11	2
A	get_parent_data_uncached_static()	0	22	5
A	get_parent()	0	15	4
A	new_query_builder()	0	3	1
A	_load_guid()	0	16	4
A	_get_parent_candidates()	0	14	4
A	is_a()	0	15	5
A	get_cached()	0	17	3
A	add_candidate()	0	15	2

<?php
/**
 * @package midcom.helper
 * @author The Midgard Project, http://www.midgard-project.org
 * @copyright The Midgard Project, http://www.midgard-project.org
 * @license http://www.gnu.org/licenses/lgpl.html GNU Lesser General Public License
 */

use midgard\portable\api\error\exception as mgd_exception;
use midgard\portable\api\mgdobject;
use midgard\portable\storage\connection;

/**
 * This class contains various factory methods to retrieve objects from the database.
 * The only instance of this class you should ever use is available through
 * midcom::get()->dbfactory.
 *
 * @package midcom.helper
 */
class midcom_helper__dbfactory
{
    /**
     * ID => GUID cache for parents
     */
    private array $_parent_mapping = [];

    /**
     * Cache for possible parent configurations per mgdschema class
     */
    private array $_parent_candidates = [];

    private string $person_class;

    private midcom_services_cache_module_memcache $memcache;

    private midcom_services_dbclassloader $dbclassloader;

    public function __construct(string $person_class, midcom_services_dbclassloader $dbclassloader, midcom_services_cache_module_memcache $memcache)
    {
        $this->person_class = $person_class;
        $this->dbclassloader = $dbclassloader;
        $this->memcache = $memcache;
    }

    /**
     * This is a replacement for the original midgard_object_class::get_object_by_guid method, which takes
     * the MidCOM DBA system into account.
     */
    public function get_object_by_guid(string $guid) : midcom_core_dbaobject
    {
        try {
            $tmp = midgard_object_class::get_object_by_guid($guid);
        } catch (mgd_exception $e) {
            debug_add('Loading object by GUID ' . $guid . ' failed, reason: ' . $e->getMessage(), MIDCOM_LOG_INFO);

            throw new midcom_error_midgard($e, $guid);
        }
        if (   get_class($tmp) == 'midgard_person'
            && $this->person_class != 'midgard_person') {
            $tmp = new $this->person_class($guid);
        }
        return $this->convert_midgard_to_midcom($tmp);
    }

    /**
     * Retrieve a reference to an object, uses in-request caching
     *
     * @param string $classname Which DBA are we dealing with
     */
    public function get_cached(string $classname, string|int $src) : midcom_core_dbaobject
    {
        static $cache = [];

        if (empty($src)) {
            throw new midcom_error('invalid source identifier');
        }

        $cache[$classname] ??= [];

        if (isset($cache[$classname][$src])) {
            return $cache[$classname][$src];
        }
        $object = new $classname($src);
        $cache[$classname][$object->guid] = $object;
        $cache[$classname][$object->id] =& $cache[$classname][$object->guid];
        return $cache[$classname][$object->guid];
    }

    /**
     * This function will determine the correct type of midgard_collector that
     * has to be created.
     *
     * @param mixed $value Value match for the collector instance
     * @see midcom_core_collector
     */
    public function new_collector(string $classname, ?string $domain, $value) : midcom_core_collector
    {
        return new midcom_core_collector($classname, $domain, $value);
    }

    /**
     * This function will determine the correct type of midgard_query_builder that
     * has to be created.
     */
    public function new_query_builder(string $classname) : midcom_core_querybuilder
    {
        return new midcom_core_querybuilder($classname);
    }

    /**
     * Convert MgdSchema object into a MidCOM DBA object.
     */
    public function convert_midgard_to_midcom(mgdobject $object) : midcom_core_dbaobject
    {
        $classname = $this->dbclassloader->get_midcom_class_name_for_mgdschema_object($object);
        return new $classname($object);
    }

    /**
     * This is a helper for emulating is_a() functionality with MidCOM DBA objects that are decorators.
     * This method can be used to check whether an object is of a MidCOM DBA or MgdSchema type
     *
     * @param mixed $object MgdSchema or MidCOM DBA object
     */
    public function is_a($object, string $class, bool $allow_string = false) : bool
    {
        if (is_a($object, $class, $allow_string)) {
            // Direct match
            return true;
        }

        if (   isset($object->__object)
            && is_object($object->__object)
            && $object->__object instanceof $class) {
            // Decorator whose MgdSchema object matches
            return true;
        }

        return false;
    }

    /**
     * Returns the parent object. Tries to utilize the Memcache
     * data, loading the actual information only if it is not cached.
     *
     * @see get_parent_data()
     * @todo rethink this, IMO we should trust midgard core's get_parent and then just do the object conversion if necessary since this can return stale objects and other nastiness
     */
    public function get_parent(midcom_core_dbaobject $object) : ?midcom_core_dbaobject
    {
        [$classname, $parent_guid] = $this->get_parent_data_cached($object->guid, function() use ($object) {
            return $this->get_parent_data_uncached($object);
        });

        if (   empty($parent_guid)
            || $parent_guid === $object->guid) {
            return null;
        }

        try {
            return $this->get_cached($classname, $parent_guid);
        } catch (midcom_error $e) {
            return null;
        }
    }

    /**
     * Determines the parent GUID for an existing GUID according to the MidCOM content tree rules.
     *
     * It tries to look up the GUID in the memory cache, only if this fails, the regular
     * content getters are invoked.
     *
     * @return array The parent GUID and class (value might be null, if this is a top level object).
     */
    public function get_parent_data(string $guid, string $class) : array
    {
        if (!mgd_is_guid($guid)) {
            throw new midcom_error('Tried to resolve an invalid GUID.');
        }
        return $this->get_parent_data_cached($guid, function() use ($guid, $class) {
            return $this->get_parent_data_uncached_static($guid, $class);
        });
    }

    private function get_parent_data_cached(string $guid, callable $callback) : array
    {
        if (mgd_is_guid($guid)) {
            $parent_data = $this->memcache->lookup_parent_data($guid);
        }

        if (empty($parent_data)) {
            // No cache hit, retrieve guid and update the cache
            $parent_data = $callback();

            if (!empty($parent_data[0])) {
                $parent_data[0] = $this->dbclassloader->get_midcom_class_name_for_mgdschema_object($parent_data[0]);
            }

            if (mgd_is_guid($guid)) {
                $this->memcache->update_parent_data($guid, $parent_data);
            }
        }

        return $parent_data;
    }

    private function get_parent_data_uncached(midcom_core_dbaobject $object) : array
    {
        $candidates = $this->_get_parent_candidates($object->__mgdschema_class_name__);
        foreach ($candidates as $data) {
            if ($data['target_property'] === 'guid') {
                return $this->get_data_from_guid($object->{$data['source_property']});
            }
            $parent_guid = $this->_load_guid($data['target_class'], $data['target_property'], $object->{$data['source_property']});
            if ($parent_guid) {
                return [$data['target_class'], $parent_guid];
            }
        }
        return ['', null];
    }

    /**
     * Get the GUID of the object's parent. This is done by reading up or parent
     * property values, which will give us the parent's ID
     */
    private function get_parent_data_uncached_static(string $object_guid, string $class_name) : array
    {
        $class_name = $this->dbclassloader->get_mgdschema_class_name_for_midcom_class($class_name);
        $candidates = $this->_get_parent_candidates($class_name);

        foreach ($candidates as $data) {
            $mc = new midgard_collector($class_name, 'guid', $object_guid);
            $mc->set_key_property($data['source_property']);
            $mc->execute();

            if ($link_values = $mc->list_keys()) {
                if ($data['target_property'] === 'guid') {
                    return $this->get_data_from_guid(key($link_values));
                }

                $parent_guid = $this->_load_guid($data['target_class'], $data['target_property'], key($link_values));
                if ($parent_guid) {
                    return [$data['target_class'], $parent_guid];
                }
            }
        }
        return ['', null];
    }

    private function get_data_from_guid(string $guid) : array
    {
        if (!mgd_is_guid($guid)) {
            return ['', null];
        }
        $class_name = connection::get_em()
            ->createQuery('SELECT r.typename from midgard_repligard r WHERE r.guid = ?1')
            ->setParameter(1, $guid)
            ->getSingleScalarResult();

        return [$class_name, $guid];
    }

    private function _load_guid(string $target_class, string $target_property, $link_value) : ?string
    {
        if (empty($link_value)) {
            return null;
        }
        if (!array_key_exists($target_class, $this->_parent_mapping)) {
            $this->_parent_mapping[$target_class] = [];
        }
        if (!array_key_exists($link_value, $this->_parent_mapping[$target_class])) {
            $mc = new midgard_collector($target_class, $target_property, $link_value);
            $mc->set_key_property('guid');
            $mc->execute();
            $this->_parent_mapping[$target_class][$link_value] = key($mc->list_keys());
        }

        return $this->_parent_mapping[$target_class][$link_value];
    }

    private function _get_parent_candidates(string $classname) : array
    {
        if (!isset($this->_parent_candidates[$classname])) {
            $this->_parent_candidates[$classname] = [];

            if ($up = midgard_object_class::get_property_up($classname)) {
                $this->add_candidate($classname, $up);
            }

            if ($parent = midgard_object_class::get_property_parent($classname)) {
                $this->add_candidate($classname, $parent);
            }
        }
        return $this->_parent_candidates[$classname];
    }

    private function add_candidate(string $classname, string $property)
    {
        $mrp = new midgard_reflection_property($classname);

        $data = [
            'source_property' => $property,
            'target_property' => $mrp->get_link_target($property) ?? 'guid',
            'target_class' => $mrp->get_link_name($property)
        ];

        if ($data['target_class'] == 'midgard_person') {
            $data['target_class'] = $this->person_class;
        }

        $this->_parent_candidates[$classname][] = $data;
    }
}