[Config] added ClassExistenceResource

src/Symfony/Component/Config/Resource/ClassExistenceResource.php

@@ -0,0 +1,75 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\Config\Resource;
+
+/**
+ * ClassExistenceResource represents a class availability.
+ * Freshness is only evaluated against resource availability.
+ *
+ * The resource must be a fully-qualified class name.
+ *
+ * @author Fabien Potencier <fabien@symfony.com>
+ */
+class ClassExistenceResource implements SelfCheckingResourceInterface, \Serializable
+{
+    private $resource;
+    private $exists;
+
+    /**
+     * @param string $resource The fully-qualified class name
+     */
+    public function __construct($resource)
+    {
+        $this->resource = $resource;
+        $this->exists = class_exists($resource);
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function __toString()
+    {
+        return $this->resource;
+    }
+
+    /**
+     * @return string The file path to the resource
+     */
+    public function getResource()
+    {
+        return $this->resource;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function isFresh($timestamp)
+    {
+        return class_exists($this->resource) === $this->exists;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function serialize()
+    {
+        return serialize(array($this->resource, $this->exists));
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function unserialize($serialized)
+    {
+        list($this->resource, $this->exists) = unserialize($serialized);
+    }
+}

src/Symfony/Component/Config/Tests/Resource/ClassExistenceResourceTest.php

@@ -0,0 +1,54 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\Config\Tests\Resource;
+
+use Symfony\Component\Config\Resource\ClassExistenceResource;
+
+class ClassExistenceResourceTest extends \PHPUnit_Framework_TestCase
+{
+    public function testToString()
+    {
+        $res = new ClassExistenceResource('BarClass');
+        $this->assertSame('BarClass', (string) $res);
+    }
+
+    public function testGetResource()
+    {
+        $res = new ClassExistenceResource('BarClass');
+        $this->assertSame('BarClass', $res->getResource());
+    }
+
+    public function testIsFreshWhenClassDoesNotExist()
+    {
+        $res = new ClassExistenceResource('Symfony\Component\Config\Tests\Fixtures\BarClass');
+
+        $this->assertTrue($res->isFresh(time()));
+
+        eval(<<<EOF
+namespace Symfony\Component\Config\Tests\Fixtures;
+
+class BarClass
+{
+}
+EOF
+        );
+
+        $this->assertFalse($res->isFresh(time()));
+    }
+
+    public function testIsFreshWhenClassExists()
+    {
+        $res = new ClassExistenceResource('Symfony\Component\Config\Tests\Resource\ClassExistenceResourceTest');
+
+        $this->assertTrue($res->isFresh(time()));
+    }
+}