Update isAbsolute() to recognize stream wrapper paths.

This has the benefit that the realpath() method is not applied to a
registered stream wrapper in the constructor of the Folder class.
Using the realpath() method will break the stream.

Thank "davalb" for the original patch.

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

@@ -548,13 +548,16 @@ public function testIsAbsolute() {
 		$this->assertFalse(Folder::isAbsolute('0:\\path\\to\\file'));
 		$this->assertFalse(Folder::isAbsolute('\\path/to/file'));
 		$this->assertFalse(Folder::isAbsolute('\\path\\to\\file'));
+		$this->assertFalse(Folder::isAbsolute('notRegisteredStreamWrapper://example'));
+		$this->assertFalse(Folder::isAbsolute('://example'));
 
 		$this->assertTrue(Folder::isAbsolute('/usr/local'));
 		$this->assertTrue(Folder::isAbsolute('//path/to/file'));
 		$this->assertTrue(Folder::isAbsolute('C:\\cake'));
 		$this->assertTrue(Folder::isAbsolute('C:\\path\\to\\file'));
 		$this->assertTrue(Folder::isAbsolute('d:\\path\\to\\file'));
 		$this->assertTrue(Folder::isAbsolute('\\\\vmware-host\\Shared Folders\\file'));
+		$this->assertTrue(Folder::isAbsolute('http://www.example.com'));
 	}
 
 /**

lib/Cake/Utility/Folder.php

@@ -278,7 +278,29 @@ public static function isWindowsPath($path) {
  * @link http://book.cakephp.org/2.0/en/core-utility-libraries/file-folder.html#Folder::isAbsolute
  */
 	public static function isAbsolute($path) {
-		return !empty($path) && ($path[0] === '/' || preg_match('/^[A-Z]:\\\\/i', $path) || substr($path, 0, 2) === '\\\\');
+		if (empty($path)) {
+			return false;
+		}
+
+		return $path[0] === '/' ||
+			preg_match('/^[A-Z]:\\\\/i', $path) ||
+			substr($path, 0, 2) === '\\\\' ||
+			self::isRegisteredStreamWrapper($path);
+	}
+
+/**
+ * Returns true if given $path is a registered stream wrapper.
+ *
+ * @param string $path Path to check
+ * @return boolean true If path is registered stream wrapper.
+ */
+	public static function isRegisteredStreamWrapper($path) {
+		if (preg_match('/^[A-Z]+(?=:\/\/)/i', $path, $matches) &&
+			in_array($matches[0], stream_get_wrappers())
+		) {
+			return true;
+		}
+		return false;
 	}
 
 /**