Issue #2671708 by alexpott, damiankloip: Add a RegexDirectoryIterator

core/lib/Drupal/Component/FileSystem/RegexDirectoryIterator.php

+<?php
+
+/**
+ * @file
+ * Contains \Drupal\Component\FileSystem\RegexDirectoryIterator.
+ */
+
+namespace Drupal\Component\FileSystem;
+
+/**
+ * Iterates over files whose names match a regular expression in a directory.
+ */
+class RegexDirectoryIterator extends \FilterIterator {
+
+  /**
+   * The regular expression to match.
+   *
+   * @var string
+   */
+  protected $regex;
+
+  /**
+   * RegexDirectoryIterator constructor.
+   *
+   * @param string $path
+   *   The path to scan.
+   * @param string $regex
+   *   The regular expression to match, including delimiters. For example,
+       /\.yml$/ would list only files ending in .yml.
+   */
+  public function __construct($path, $regex) {
+    // Use FilesystemIterator to not iterate over the the . and .. directories.
+    $iterator = new \FilesystemIterator($path);
+    parent::__construct($iterator);
+    $this->regex = $regex;
+  }
+
+  /**
+   * Implements \FilterIterator::accept().
+   */
+  public function accept() {
+    /** @var \SplFileInfo $file_info */
+    $file_info = $this->getInnerIterator()->current();
+    return $file_info->isFile() && preg_match($this->regex, $file_info->getFilename());
+  }
+
+}

core/tests/Drupal/Tests/Component/FileSystem/RegexDirectoryIteratorTest.php

+<?php
+
+/**
+ * @file
+ * Contains \Drupal\Tests\Component\FileSystem\RegexDirectoryIteratorTest.
+ */
+
+namespace Drupal\Tests\Component\FileSystem;
+
+use Drupal\Component\FileSystem\RegexDirectoryIterator;
+use Drupal\Tests\UnitTestCase;
+use org\bovigo\vfs\vfsStream;
+
+/**
+ * @coversDefaultClass \Drupal\Component\FileSystem\RegexDirectoryIterator
+ * @group FileSystem
+ */
+class RegexDirectoryIteratorTest extends UnitTestCase {
+
+  /**
+   * @covers ::accept
+   * @dataProvider providerTestRegexDirectoryIterator
+   */
+  public function testRegexDirectoryIterator(array $directory, $regex, array $expected) {
+    vfsStream::setup('root', NULL, $directory);
+    $iterator = new RegexDirectoryIterator(vfsStream::url('root'), $regex);
+
+    // Create an array of filenames to assert against.
+    $file_list = array_map(function(\SplFileInfo $file) {
+      return $file->getFilename();
+    }, array_values(iterator_to_array($iterator)));
+
+    $this->assertSame($expected, $file_list);
+  }
+
+  /**
+   * Provider for self::testRegexDirectoryIterator().
+   */
+  public function providerTestRegexDirectoryIterator() {
+    return [
+      [
+        [
+          '1.yml' => '',
+        ],
+        '/\.yml$/',
+        [
+          '1.yml',
+        ],
+      ],
+      [
+        [
+          '1.yml' => '',
+          '2.yml' => '',
+          '3.txt' => '',
+        ],
+        '/\.yml$/',
+        [
+          '1.yml',
+          '2.yml',
+        ],
+      ],
+      [
+        [
+          '1.yml' => '',
+          '2.yml' => '',
+          '3.txt' => '',
+        ],
+        '/\.txt/',
+        [
+          '3.txt',
+        ],
+      ],
+      [
+        [
+          '1.yml' => '',
+          // Ensure we don't recurse in directories even if that match the
+          // regex.
+          '2.yml' => [
+            '3.yml' => '',
+            '4.yml' => '',
+          ],
+          '3.txt' => '',
+        ],
+        '/\.yml$/',
+        [
+          '1.yml',
+        ],
+      ],
+      [
+        [
+          '1.yml' => '',
+          '2.yml' => '',
+          '3.txt' => '',
+        ],
+        '/^\d/',
+        [
+          '1.yml',
+          '2.yml',
+          '3.txt'
+        ],
+      ],
+      [
+        [
+          '1.yml' => '',
+          '2.yml' => '',
+          '3.txt' => '',
+        ],
+        '/^\D/',
+        [],
+      ],
+    ];
+  }
+
+}