IBX-843: Introduced ContentLocationMapper

For more details see https://issues.ibexa.co/browse/IBX-843 and ezsystems/ezplatform-kernel#249

* Created InMemoryContentLocationMapper

* Implemented LocationService hooks for ContentLocationMapper

* Registered DI services

* Created unit tests

eZ/Bundle/EzPublishCoreBundle/DependencyInjection/EzPublishCoreExtension.php

@@ -344,6 +344,7 @@ private function handleApiLoading(ContainerBuilder $container, FileLoader $loade
         $coreLoader->load('user_preference.yml');
         $coreLoader->load('events.yml');
         $coreLoader->load('thumbnails.yml');
+        $coreLoader->load('content_location_mapper.yml');
 
         // Public API services
         $loader->load('papi.yml');

eZ/Publish/Core/Repository/Mapper/ContentLocationMapper/ContentLocationMapper.php

@@ -0,0 +1,23 @@
+<?php
+
+/**
+ * @copyright Copyright (C) Ibexa AS. All rights reserved.
+ * @license For full copyright and license information view LICENSE file distributed with this source code.
+ */
+declare(strict_types=1);
+
+namespace eZ\Publish\Core\Repository\Mapper\ContentLocationMapper;
+
+/**
+ * @internal For internal use by Ibexa packages only
+ */
+interface ContentLocationMapper
+{
+    public function hasMapping(int $locationId): bool;
+
+    public function getMapping(int $locationId): int;
+
+    public function setMapping(int $locationId, int $contentId): void;
+
+    public function removeMapping(int $locationId): void;
+}

eZ/Publish/Core/Repository/Mapper/ContentLocationMapper/DecoratedLocationService.php

@@ -0,0 +1,131 @@
+<?php
+
+/**
+ * @copyright Copyright (C) Ibexa AS. All rights reserved.
+ * @license For full copyright and license information view LICENSE file distributed with this source code.
+ */
+declare(strict_types=1);
+
+namespace eZ\Publish\Core\Repository\Mapper\ContentLocationMapper;
+
+use eZ\Publish\API\Repository\LocationService as RepositoryLocationService;
+use eZ\Publish\API\Repository\Values\Content\ContentInfo;
+use eZ\Publish\API\Repository\Values\Content\Location;
+use eZ\Publish\API\Repository\Values\Content\LocationList;
+use eZ\Publish\SPI\Repository\Decorator\LocationServiceDecorator;
+
+/**
+ * Service decorator hooking ContentLocationMapper to load* calls.
+ *
+ * @internal
+ */
+final class DecoratedLocationService extends LocationServiceDecorator
+{
+    /** @var \eZ\Publish\Core\Repository\Mapper\ContentLocationMapper\ContentLocationMapper */
+    private $contentLocationMapper;
+
+    public function __construct(
+        RepositoryLocationService $innerService,
+        ContentLocationMapper $contentLocationMapper
+    ) {
+        parent::__construct($innerService);
+
+        $this->contentLocationMapper = $contentLocationMapper;
+    }
+
+    public function loadLocation(
+        int $locationId,
+        ?array $prioritizedLanguages = null,
+        ?bool $useAlwaysAvailable = null
+    ): Location {
+        $location = $this->innerService->loadLocation(
+            $locationId,
+            $prioritizedLanguages,
+            $useAlwaysAvailable
+        );
+
+        $this->contentLocationMapper->setMapping(
+            $locationId,
+            $location->contentId
+        );
+
+        return $location;
+    }
+
+    public function loadLocationList(
+        array $locationIds,
+        ?array $prioritizedLanguages = null,
+        ?bool $useAlwaysAvailable = null
+    ): iterable {
+        $locationList = $this->innerService->loadLocationList(
+            $locationIds,
+            $prioritizedLanguages,
+            $useAlwaysAvailable
+        );
+
+        $this->setLocationMappings($locationList);
+
+        return $locationList;
+    }
+
+    public function loadLocations(
+        ContentInfo $contentInfo,
+        ?Location $rootLocation = null,
+        ?array $prioritizedLanguages = null
+    ): iterable {
+        $locations = $this->innerService->loadLocations(
+            $contentInfo,
+            $rootLocation,
+            $prioritizedLanguages
+        );
+
+        $this->setLocationMappings($locations);
+
+        return $locations;
+    }
+
+    public function loadLocationChildren(
+        Location $location,
+        int $offset = 0,
+        int $limit = 25,
+        ?array $prioritizedLanguages = null
+    ): LocationList {
+        $locationChildren = $this->innerService->loadLocationChildren(
+            $location,
+            $offset,
+            $limit,
+            $prioritizedLanguages
+        );
+
+        $this->setLocationMappings($locationChildren->locations);
+
+        return $locationChildren;
+    }
+
+    public function loadAllLocations(
+        int $offset = 0,
+        int $limit = 25
+    ): array {
+        $locations = $this->innerService->loadAllLocations(
+            $offset,
+            $limit
+        );
+
+        $this->setLocationMappings($locations);
+
+        return $locations;
+    }
+
+    /**
+     * @param iterable<\eZ\Publish\API\Repository\Values\Content\Location>
+     */
+    private function setLocationMappings(iterable $locationList): void
+    {
+        foreach ($locationList as $location) {
+            $this->contentLocationMapper->setMapping(
+                $location->id,
+                $location->contentId
+            );
+        }
+    }
+}

eZ/Publish/Core/Repository/Mapper/ContentLocationMapper/InMemoryContentLocationMapper.php

@@ -0,0 +1,56 @@
+<?php
+
+/**
+ * @copyright Copyright (C) Ibexa AS. All rights reserved.
+ * @license For full copyright and license information view LICENSE file distributed with this source code.
+ */
+declare(strict_types=1);
+
+namespace eZ\Publish\Core\Repository\Mapper\ContentLocationMapper;
+
+/**
+ * Retrieves Content ID from Location ID.
+ *
+ * Helps in scenarios where you need to retrieve Content IDs from
+ * a large location list. You'd normally do LocationService::loadLocation call
+ * for every Location ID which requires a lot of memory.
+ *
+ * It works by tracing all loadLocation calls via Service\LocationService decorator
+ * and updating the map accordingly. Currently, in memory cache mechanism is used but
+ * can be further optimized by implementing persistence cache.
+ *
+ * @internal For internal use by Ibexa packages only
+ */
+final class InMemoryContentLocationMapper implements ContentLocationMapper
+{
+    /** @var Array<int, int> */
+    private $map;
+
+    /**
+     * @param int[] $map
+     */
+    public function __construct(array $map = [])
+    {
+        $this->map = $map;
+    }
+
+    public function hasMapping(int $locationId): bool
+    {
+        return isset($this->map[$locationId]);
+    }
+
+    public function getMapping(int $locationId): int
+    {
+        return $this->map[$locationId];
+    }
+
+    public function setMapping(int $locationId, int $contentId): void
+    {
+        $this->map[$locationId] = $contentId;
+    }
+
+    public function removeMapping(int $locationId): void
+    {
+        unset($this->map[$locationId]);
+    }
+}

eZ/Publish/Core/Repository/Mapper/Readme.md

@@ -1,7 +1,6 @@
 # Mappers
 
-Collection of light mappers meant for internal use in Repository
-and/or RepositoryServices.
+Collection of light mappers meant for internal use by Ibexa packages only.
 
-Given their use they can not rely on Repository or RepositoryServices as
-that will lead to cyclic dependencies, they can only rely on SPI and other helpers.
+Given their use they should not rely on Repository or RepositoryServices as
+that will lead to cyclic dependencies, they should only rely on SPI and other helpers.