added DibiLazyStorage, simple caching layer

dibi/dibi.php

@@ -107,6 +107,7 @@ class DibiVariable extends DateTime53
 // dibi libraries
 require_once dirname(__FILE__) . '/libs/interfaces.php';
 require_once dirname(__FILE__) . '/libs/DibiObject.php';
+require_once dirname(__FILE__) . '/libs/DibiLazyStorage.php';
 require_once dirname(__FILE__) . '/libs/DibiException.php';
 require_once dirname(__FILE__) . '/libs/DibiConnection.php';
 require_once dirname(__FILE__) . '/libs/DibiResult.php';

dibi/libs/DibiLazyStorage.php

@@ -0,0 +1,66 @@
+<?php
+
+/**
+ * dibi - tiny'n'smart database abstraction layer
+ * ----------------------------------------------
+ *
+ * @copyright  Copyright (c) 2005, 2010 David Grudl
+ * @license    http://dibiphp.com/license  dibi license
+ * @link       http://dibiphp.com
+ * @package    dibi
+ */
+
+
+
+/**#@+
+ * Lazy cached storage.
+ *
+ * @copyright  Copyright (c) 2005, 2010 David Grudl
+ * @package    dibi
+ * @internal
+ */
+abstract class DibiLazyStorageBase
+{
+	private $callback;
+
+
+	public function __construct($callback)
+	{
+		$this->setCallback($callback);
+	}
+
+
+
+	public function setCallback($callback)
+	{
+		if (!is_callable($callback)) {
+			$able = is_callable($callback, TRUE, $textual);
+			throw new InvalidArgumentException("Handler '$textual' is not " . ($able ? 'callable.' : 'valid PHP callback.'));
+		}
+		$this->callback = $callback;
+	}
+
+
+
+	public function getCallback()
+	{
+		return $this->callback;
+	}
+
+}
+
+
+
+final class DibiLazyStorage extends DibiLazyStorageBase
+{
+
+	public function __get($nm)
+	{
+		if (is_array($nm)) { // preg_replace_callback support
+			$nm = $nm[1];
+		}
+		return $this->$nm = call_user_func($this->getCallback(), $nm);
+	}
+
+}
+/**#@-*/