Add Preprocessor Loader that allows pre-filtering template code.

lib/Twig/Loader/Preprocessor.php

@@ -0,0 +1,91 @@
+<?php
+
+/*
+ * This file is part of Twig.
+ *
+ * (c) 2011 Fabien Potencier
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+/**
+ * Twig Preprocessor loader that allows adding custom text filters for template strings.
+ *
+ * For instance, you can make Twig produce more readable output by stripping leading
+ * spaces in lines with single control structure or comment:
+ *
+ * $loader = new Twig_Loader_Preprocessor($realLoader,
+ *     function ($template) {
+ *         return preg_replace('/^[ \t]*(\{([#%])[^}]*(?2)\})$/m', '$1', $template);
+ *     }
+ * );
+ *
+ * See also twig issue #1005: https://github.com/fabpot/Twig/issues/1005
+ *
+ * @author Igor Tarasov <[email protected]>
+ */
+class Twig_Loader_Preprocessor implements Twig_LoaderInterface, Twig_ExistsLoaderInterface
+{
+    private $realLoader;
+    private $callback;
+
+    /**
+     * Constructor
+     *
+     * Callback should accept template string as the only argument and return the result
+     *
+     * @param Twig_LoaderInterface $loader A loader that does real loading of templates
+     * @param callable $callback The processing callback
+     */
+    public function __construct(Twig_LoaderInterface $loader, $callback)
+    {
+        $this->realLoader = $loader;
+        $this->callback = $callback;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function getSource($name)
+    {
+        return call_user_func($this->callback, $this->realLoader->getSource($name));
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function exists($name)
+    {
+        $name = (string) $name;
+
+        if ($this->realLoader instanceof Twig_ExistsLoaderInterface) {
+            return $this->realLoader->exists($name);
+        } else {
+            try {
+                $this->realLoader->getSource($name);
+
+                return true;
+            } catch (Twig_Error_Loader $e) {
+            }
+        }
+
+        return false;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function getCacheKey($name)
+    {
+        return $this->realLoader->getCacheKey($name);
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function isFresh($name, $time)
+    {
+        return $this->realLoader->isFresh($name, $time);
+    }
+}

test/Twig/Tests/Loader/PreprocessorTest.php

@@ -0,0 +1,36 @@
+<?php
+
+/*
+ * This file is part of Twig.
+ *
+ * (c) Fabien Potencier
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+class Twig_Tests_Loader_PreprocessorTest extends PHPUnit_Framework_TestCase
+{
+    public function testProcessing()
+    {
+        $realLoader = new Twig_Loader_String();
+        $loader = new Twig_Loader_Preprocessor($realLoader, 'strtoupper');
+        $this->assertEquals('TEST', $loader->getSource('test'));
+    }
+
+    public function testExists()
+    {
+        $realLoader = $this->getMock('Twig_Loader_Array', array('exists', 'getSource'), array(), '', false);
+        $realLoader->expects($this->once())->method('exists')->will($this->returnValue(false));
+        $realLoader->expects($this->never())->method('getSource');
+
+        $loader = new Twig_Loader_Preprocessor($realLoader, 'trim');
+        $this->assertFalse($loader->exists('foo'));
+
+        $realLoader = $this->getMock('Twig_LoaderInterface');
+        $realLoader->expects($this->once())->method('getSource')->will($this->returnValue('content'));
+
+        $loader = new Twig_Loader_Preprocessor($realLoader, 'trim');
+        $this->assertTrue($loader->exists('foo'));
+    }
+}