Provide array cache implementation

doctrine/cache 2.0 no longer provides implementations of caches. It provides only interfaces.
We need only PHP array cache so I chose to implement this simple cache instead of introducing
new cache library.
[MAILPOET-3892]

lib/Doctrine/ArrayCache.php

@@ -0,0 +1,97 @@
+<?php
+
+namespace MailPoet\Doctrine;
+
+use MailPoetVendor\Doctrine\Common\Cache\CacheProvider;
+
+/**
+ * Array cache
+ * Based on https://github.com/doctrine/cache/blob/1.11.x/lib/Doctrine/Common/Cache/ArrayCache.php
+ * The cache implementation was removed from the doctrine/cache v2.0 so we need to provide own implementation.
+ */
+class ArrayCache extends CacheProvider
+{
+  /** @var mixed[] */
+  private $data = [];
+
+  /** @var int */
+  private $hitsCount = 0;
+
+  /** @var int */
+  private $missesCount = 0;
+
+  /** @var int */
+  private $upTime;
+
+  /**
+   * {@inheritdoc}
+   */
+  public function __construct()
+  {
+    $this->upTime = time();
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function doFetch($id) {
+    if (! $this->doContains($id)) {
+      $this->missesCount += 1;
+      return false;
+    }
+    $this->hitsCount += 1;
+    return $this->data[$id][0];
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function doContains($id) {
+    if (! isset($this->data[$id])) {
+      return false;
+    }
+    $expiration = $this->data[$id][1];
+    if ($expiration && $expiration < \time()) {
+      $this->doDelete($id);
+      return false;
+    }
+    return true;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function doSave($id, $data, $lifeTime = 0) {
+    $this->data[$id] = [$data, $lifeTime ? \time() + $lifeTime : false];
+    return true;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function doDelete($id) {
+    unset($this->data[$id]);
+    return true;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function doFlush() {
+    $this->data = [];
+    return true;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function doGetStats() {
+    return [
+      CacheProvider::STATS_HITS             => $this->hitsCount,
+      CacheProvider::STATS_MISSES           => $this->missesCount,
+      CacheProvider::STATS_UPTIME           => $this->upTime,
+      CacheProvider::STATS_MEMORY_USAGE     => null,
+      CacheProvider::STATS_MEMORY_AVAILABLE => null,
+    ];
+  }
+}

lib/Doctrine/ConfigurationFactory.php

@@ -3,7 +3,6 @@
 namespace MailPoet\Doctrine;
 
 use MailPoet\Doctrine\Annotations\AnnotationReaderProvider;
-use MailPoetVendor\Doctrine\Common\Cache\ArrayCache;
 use MailPoetVendor\Doctrine\Common\Proxy\AbstractProxyFactory;
 use MailPoetVendor\Doctrine\ORM\Configuration;
 use MailPoetVendor\Doctrine\ORM\Mapping\Driver\AnnotationDriver;

tests/integration/Doctrine/ConfigurationFactoryTest.php

@@ -3,11 +3,10 @@
 namespace MailPoet\Test\Config;
 
 use MailPoet\Doctrine\Annotations\AnnotationReaderProvider;
+use MailPoet\Doctrine\ArrayCache;
 use MailPoet\Doctrine\ConfigurationFactory;
-use MailPoet\Doctrine\MetadataCache;
 use MailPoet\Doctrine\PSRMetadataCache;
 use MailPoet\Doctrine\TablePrefixMetadataFactory;
-use MailPoetVendor\Doctrine\Common\Cache\ArrayCache;
 use MailPoetVendor\Doctrine\Common\Proxy\AbstractProxyFactory;
 use MailPoetVendor\Doctrine\ORM\Configuration;
 use MailPoetVendor\Doctrine\ORM\Mapping\Driver\AnnotationDriver;

tests/integration/Doctrine/EventListeners/ValidationTest.php

@@ -3,6 +3,7 @@
 namespace MailPoet\Test\Doctrine\EventListeners;
 
 use MailPoet\Doctrine\Annotations\AnnotationReaderProvider;
+use MailPoet\Doctrine\ArrayCache;
 use MailPoet\Doctrine\ConfigurationFactory;
 use MailPoet\Doctrine\EntityManagerFactory;
 use MailPoet\Doctrine\EventListeners\EmojiEncodingListener;
@@ -13,7 +14,6 @@ use MailPoet\Doctrine\Validator\ValidationException;
 use MailPoet\Doctrine\Validator\ValidatorFactory;
 use MailPoet\WP\Emoji;
 use MailPoet\WP\Functions as WPFunctions;
-use MailPoetVendor\Doctrine\Common\Cache\ArrayCache;
 
 require_once __DIR__ . '/ValidatedEntity.php';
 

tests/integration/Doctrine/Types/JsonTypesTest.php

@@ -4,6 +4,7 @@ namespace MailPoet\Test\Doctrine\EventListeners;
 
 use Exception;
 use MailPoet\Doctrine\Annotations\AnnotationReaderProvider;
+use MailPoet\Doctrine\ArrayCache;
 use MailPoet\Doctrine\ConfigurationFactory;
 use MailPoet\Doctrine\EntityManagerFactory;
 use MailPoet\Doctrine\EventListeners\EmojiEncodingListener;
@@ -14,7 +15,6 @@ use MailPoet\Doctrine\Validator\ValidatorFactory;
 use MailPoet\Test\Doctrine\Types\JsonEntity;
 use MailPoet\WP\Emoji;
 use MailPoet\WP\Functions as WPFunctions;
-use MailPoetVendor\Doctrine\Common\Cache\ArrayCache;
 use RuntimeException;
 
 require_once __DIR__ . '/JsonEntity.php';