Add a "resolve" method to Path

Tests/PathTest.php

@@ -6,6 +6,7 @@
 
 namespace Joomla\Filesystem\Tests;
 
+use Joomla\Filesystem\Exception\FilesystemException;
 use Joomla\Filesystem\File;
 use Joomla\Filesystem\Path;
 
@@ -362,4 +363,87 @@ public function testFind()
 			Path::find(__DIR__, 'PathTest.php')
 		);
 	}
+
+	/**
+	 * Test resolve method
+	 *
+	 * @param   string  $path            test path
+	 * @param   string  $expectedResult  expected path
+	 *
+	 * @return  void
+	 *
+	 * @since   1.4.0
+	 *
+	 * @dataProvider  getResolveData
+	 */
+	public function testResolve($path, $expectedResult)
+	{
+		$this->assertEquals(str_replace("_DS_", DIRECTORY_SEPARATOR, $expectedResult), Path::resolve($path));
+	}
+
+	/**
+	 * Test resolve method
+
+	 * @param   string  $path            test path
+	 *
+	 * @expectedException         Joomla\Filesystem\Exception\FilesystemException
+	 * @expectedExceptionMessage  Path is outside of the defined root
+	 *
+	 * @return void
+	 *
+	 * @since   1.4.0
+	 *
+	 * @dataProvider  getResolveExceptionData
+	 */
+	public function testResolveThrowsExceptionIfRootIsLeft($path)
+	{
+		Path::resolve($path);
+	}
+
+	/**
+	 * Data provider for testResolve() method.
+	 *
+	 * @return  array
+	 *
+	 * @since   1.0
+	 */
+	public function getResolveData()
+	{
+		return array(
+			array("/", "_DS_"),
+			array("a", "a"),
+			array("/test/", "_DS_test"),
+			array("C:/", "C:"),
+			array("/var/www/joomla", "_DS_var_DS_www_DS_joomla"),
+			array("C:/iis/www/joomla", "C:_DS_iis_DS_www_DS_joomla"),
+			array("var/www/joomla", "var_DS_www_DS_joomla"),
+			array("./var/www/joomla", "var_DS_www_DS_joomla"),
+			array("/var/www/foo/../joomla", "_DS_var_DS_www_DS_joomla"),
+			array("C:/var/www/foo/../joomla", "C:_DS_var_DS_www_DS_joomla"),
+			array("/var/www/../foo/../joomla", "_DS_var_DS_joomla"),
+			array("C:/var/www/..foo../joomla", "C:_DS_var_DS_www_DS_..foo.._DS_joomla"),
+			array("c:/var/www/..foo../joomla", "c:_DS_var_DS_www_DS_..foo.._DS_joomla"),
+			array("/var/www///joomla", "_DS_var_DS_www_DS_joomla"),
+			array("/var///www///joomla", "_DS_var_DS_www_DS_joomla"),
+			array("C:/var///www///joomla", "C:_DS_var_DS_www_DS_joomla"),
+			array("/var/\/../www///joomla", "_DS_www_DS_joomla"),
+			array("C:/var///www///joomla", "C:_DS_var_DS_www_DS_joomla"),
+			array("/var\\www///joomla", "_DS_var_DS_www_DS_joomla")
+		);
+	}
+
+	/**
+	 * Data provider for testResolve() method.
+	 *
+	 * @return  array
+	 *
+	 * @since   1.0
+	 */
+	public function getResolveExceptionData()
+	{
+		return array(
+			array("../var/www/joomla"),
+			array("/var/../../../www/joomla")
+		);
+	}
 }

src/Path.php

@@ -340,4 +340,49 @@ public static function find($paths, $file)
 		// Could not find the file in the set of paths
 		return false;
 	}
+
+	/**
+	 * Resolves /./, /../ and multiple / in a string and returns the resulting absolute path, inspired by Flysystem
+	 * Removes trailing slashes
+	 *
+	 * @param   string   $path   A path to resolve
+	 *
+	 * @return  string  The resolved path
+	 *
+	 * @since   __DEPLOY_VERSION__
+	 */
+	public static function resolve($path)
+	{
+		$path = static::clean($path);
+
+		// Save start character for absolute path
+		$startCharacter = ($path[0] === DIRECTORY_SEPARATOR) ? DIRECTORY_SEPARATOR : '';
+
+		$parts = array();
+
+		foreach (explode(DIRECTORY_SEPARATOR, $path) as $part)
+		{
+			switch ($part)
+			{
+				case '':
+				case '.':
+					break;
+
+				case '..':
+					if (empty($parts))
+					{
+						throw new FilesystemException('Path is outside of the defined root');
+					}
+
+					array_pop($parts);
+					break;
+
+				default:
+					$parts[] = $part;
+					break;
+			}
+		}
+
+		return $startCharacter . implode(DIRECTORY_SEPARATOR, $parts);
+	}
 }