Backport 5714cf1 to 2.x

Fix file:// paths being mishandled on windows.

While I don't think its feasible to fix all the cases reported in #7275
as certain paths have different meaning in windows, we can fix file://
not working.

Refs #7275

lib/Cake/Test/Case/Utility/FileTest.php

@@ -301,6 +301,23 @@ public function testCreate() {
 		$this->assertTrue($File->exists());
 	}
 
+/**
+ * Tests the exists() method.
+ *
+ * @return void
+ */
+	public function testExists() {
+		$tmpFile = TMP . 'tests/cakephp.file.test.tmp';
+		$file = new File($tmpFile, true, 0777);
+		$this->assertTrue($file->exists(), 'absolute path should exist');
+
+		$file = new File('file://' . $tmpFile, false);
+		$this->assertTrue($file->exists(), 'file:// should exist.');
+
+		$file = new File('/something/bad', false);
+		$this->assertFalse($file->exists(), 'missing file should not exist.');
+	}
+
 /**
  * testOpeningNonExistentFileCreatesIt method
  *

lib/Cake/Utility/Folder.php

@@ -821,13 +821,13 @@ public function errors($reset = true) {
  * @link http://book.cakephp.org/2.0/en/core-utility-libraries/file-folder.html#Folder::realpath
  */
 	public function realpath($path) {
-		$path = str_replace('/', DS, trim($path));
 		if (strpos($path, '..') === false) {
 			if (!Folder::isAbsolute($path)) {
 				$path = Folder::addPathElement($this->path, $path);
 			}
 			return $path;
 		}
+		$path = str_replace('/', DS, trim($path));
 		$parts = explode(DS, $path);
 		$newparts = array();
 		$newpath = '';