Config FollowUp

- New Configuration (Config is now only holding the instance)
- New PConfiguration (PConfig is now only holding the instance)

- Config & PConfig-Adapter don't need "ConfigCache" anymore

- DB-Connection is now outside App->reload() for better dependency-chaining

src/Core/Config/Adapter/PreloadConfigAdapter.php

@@ -0,0 +1,104 @@
+<?php
+
+namespace Friendica\Core\Config\Adapter;
+
+use Friendica\Database\DBA;
+
+/**
+ * Preload Configuration Adapter
+ *
+ * Minimizes the number of database queries to retrieve configuration values at the cost of memory.
+ *
+ * @author Hypolite Petovan <hypolite@mrpetovan.com>
+ */
+class PreloadConfigAdapter extends AbstractDbaConfigAdapter implements IConfigAdapter
+{
+	private $config_loaded = false;
+
+	/**
+	 * {@inheritdoc}
+	 */
+	public function load($cat = 'config')
+	{
+		$return = [];
+
+		if (!$this->isConnected()) {
+			return $return;
+		}
+
+		if ($this->config_loaded) {
+			return $return;
+		}
+
+		$configs = DBA::select('config', ['cat', 'v', 'k']);
+		while ($config = DBA::fetch($configs)) {
+			$return[$config['k']] = $config['v'];
+		}
+		DBA::close($configs);
+
+		$this->config_loaded = true;
+
+		return [$cat => $return];
+	}
+
+	/**
+	 * {@inheritdoc}
+	 */
+	public function get($cat, $key)
+	{
+		if (!$this->isConnected()) {
+			return null;
+		}
+
+		$config = DBA::selectFirst('config', ['v'], ['cat' => $cat, 'k' => $key]);
+		if (DBA::isResult($config)) {
+			// manage array value
+			$value = (preg_match("|^a:[0-9]+:{.*}$|s", $config['v']) ? unserialize($config['v']) : $config['v']);
+
+			return $value;
+		} else {
+
+			return '!<unset>!';
+		}
+	}
+
+	/**
+	 * {@inheritdoc}
+	 */
+	public function set($cat, $key, $value)
+	{
+		if (!$this->isConnected()) {
+			return false;
+		}
+
+		// We store our setting values as strings.
+		// So we have to do the conversion here so that the compare below works.
+		// The exception are array values.
+		$compare_value = !is_array($value) ? (string)$value : $value;
+
+		if ($this->get($cat, $key) === $compare_value) {
+			return true;
+		}
+
+		// manage array value
+		$dbvalue = is_array($value) ? serialize($value) : $value;
+
+		$result = DBA::update('config', ['v' => $dbvalue], ['cat' => $cat, 'k' => $key], true);
+
+		return $result;
+	}
+
+	/**
+	 * {@inheritdoc}
+	 */
+	public function delete($cat, $key)
+	{
+		if (!$this->isConnected()) {
+			return false;
+		}
+
+		$result = DBA::delete('config', ['cat' => $cat, 'k' => $key]);
+
+		return $result;
+	}
+}