Introduce ISetConfigValuesTransactional for transactional config behaviour

src/Core/Config/Model/Config.php

@@ -22,6 +22,7 @@
 namespace Friendica\Core\Config\Model;
 
 use Friendica\Core\Config\Capability\IManageConfigValues;
+use Friendica\Core\Config\Capability\ISetConfigValuesTransactional;
 use Friendica\Core\Config\Exception\ConfigFileException;
 use Friendica\Core\Config\Exception\ConfigPersistenceException;
 use Friendica\Core\Config\Util\ConfigFileManager;
@@ -61,8 +62,17 @@ class Config implements IManageConfigValues
 		return $this->configCache;
 	}
 
-	/** {@inheritDoc} */
-	public function save()
+	/**	{@inheritDoc} */
+	public function transactional(): ISetConfigValuesTransactional
+	{
+		return new TransactionalConfig($this);
+	}
+
+	/**
+	 * Saves the current Configuration back into the data config.
+	 * @see ConfigFileManager::CONFIG_DATA_FILE
+	 */
+	protected function save()
 	{
 		try {
 			$this->configFileManager->saveData($this->configCache);
@@ -84,6 +94,13 @@ class Config implements IManageConfigValues
 		$this->configCache = $configCache;
 	}
 
+	/** {@inheritDoc} */
+	public function load(Cache $cache)
+	{
+		$this->configCache = $cache;
+		$this->save();
+	}
+
 	/** {@inheritDoc} */
 	public function get(string $cat, string $key, $default_value = null)
 	{
@@ -91,26 +108,24 @@ class Config implements IManageConfigValues
 	}
 
 	/** {@inheritDoc} */
-	public function set(string $cat, string $key, $value, bool $autosave = true): bool
+	public function set(string $cat, string $key, $value): bool
 	{
-		$stored = $this->configCache->set($cat, $key, $value, Cache::SOURCE_DATA);
-
-		if ($stored && $autosave) {
+		if ($this->configCache->set($cat, $key, $value, Cache::SOURCE_DATA)) {
 			$this->save();
+			return true;
+		} else {
+			return false;
 		}
-
-		return $stored;
 	}
 
 	/** {@inheritDoc} */
-	public function delete(string $cat, string $key, bool $autosave = true): bool
+	public function delete(string $cat, string $key): bool
 	{
-		$removed = $this->configCache->delete($cat, $key);
-
-		if ($removed && $autosave) {
+		if ($this->configCache->delete($cat, $key)) {
 			$this->save();
+			return true;
+		} else {
+			return false;
 		}
-
-		return $removed;
 	}
 }

src/Core/Config/Model/TransactionalConfig.php

@@ -0,0 +1,89 @@
+<?php
+/**
+ * @copyright Copyright (C) 2010-2023, the Friendica project
+ *
+ * @license GNU AGPL version 3 or any later version
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ *
+ */
+
+namespace Friendica\Core\Config\Model;
+
+use Friendica\Core\Config\Capability\IManageConfigValues;
+use Friendica\Core\Config\Capability\ISetConfigValuesTransactional;
+use Friendica\Core\Config\Exception\ConfigPersistenceException;
+use Friendica\Core\Config\ValueObject\Cache;
+
+/**
+ * config class, which sets values into a temporary buffer until "save()" is called
+ */
+class TransactionalConfig implements ISetConfigValuesTransactional
+{
+	/** @var IManageConfigValues */
+	protected $config;
+	/** @var Cache */
+	protected $cache;
+	/** @var Cache */
+	protected $delCache;
+
+	public function __construct(IManageConfigValues $config)
+	{
+		$this->config   = $config;
+		$this->cache    = new Cache();
+		$this->delCache = new Cache();
+	}
+
+	/** {@inheritDoc} */
+	public function get(string $cat, string $key)
+	{
+		return !$this->delCache->get($cat, $key) ?
+			($this->cache->get($cat, $key) ?? $this->config->get($cat, $key)) :
+			null;
+	}
+
+	/** {@inheritDoc} */
+	public function set(string $cat, string $key, $value): ISetConfigValuesTransactional
+	{
+		$this->cache->set($cat, $key, $value, Cache::SOURCE_DATA);
+
+		return $this;
+	}
+
+
+	/** {@inheritDoc} */
+	public function delete(string $cat, string $key): ISetConfigValuesTransactional
+	{
+		$this->cache->delete($cat, $key);
+		$this->delCache->set($cat, $key, 'deleted');
+
+		return $this;
+	}
+
+	/** {@inheritDoc} */
+	public function save(): void
+	{
+		try {
+			$newCache = $this->config->getCache()->merge($this->cache);
+			$newCache = $newCache->diff($this->delCache);
+			$this->config->load($newCache);
+
+			// flush current cache
+			$this->cache    = new Cache();
+			$this->delCache = new Cache();
+		} catch (\Exception $e) {
+			throw new ConfigPersistenceException('Cannot save config', $e);
+		}
+	}
+}