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kirby/src/Content/VersionCache.php

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+<?php
+
+namespace Kirby\Content;
+
+use Kirby\Cms\Language;
+use WeakMap;
+
+/**
+ * The Version cache class keeps content fields
+ * to avoid multiple storage reads for the same
+ * content.
+ *
+ * @package   Kirby Content
+ * @author    Bastian Allgeier <bastian@getkirby.com>
+ * @link      https://getkirby.com
+ * @copyright Bastian Allgeier
+ * @license   https://getkirby.com/license
+ * @since     5.0.0
+ * @unstable
+ */
+class VersionCache
+{
+	/**
+	 * All cache values for all versions
+	 * and language combinations
+	 */
+	protected static WeakMap $cache;
+
+	/**
+	 * Tries to receive a fields for a version/language combination
+	 */
+	public static function get(Version $version, Language $language): array|null
+	{
+		$model = $version->model();
+		$key   = $version->id() . ':' . $language->code();
+
+		return static::$cache[$model][$key] ?? null;
+	}
+
+	/**
+	 * Removes fields for a version/language combination
+	 */
+	public static function remove(Version $version, Language $language): void
+	{
+		$model = $version->model();
+
+		if (isset(static::$cache[$model]) === false) {
+			return;
+		}
+
+		// Avoid indirect manipulation of WeakMap
+		$key = $version->id() . ':' . $language->code();
+		$map = static::$cache[$model];
+		unset($map[$key]);
+		static::$cache[$model] = $map;
+	}
+
+	/**
+	 * Resets the cache
+	 */
+	public static function reset(): void
+	{
+		static::$cache = new WeakMap();
+	}
+
+	/**
+	 * Keeps fields for a version/language combination
+	 */
+	public static function set(
+		Version $version,
+		Language $language,
+		array $fields = []
+	): void {
+		$model = $version->model();
+		$key   = $version->id() . ':' . $language->code();
+
+		static::$cache ??= new WeakMap();
+		static::$cache[$model] ??= [];
+		static::$cache[$model][$key] = $fields;
+	}
+}