--- /dev/null
+<?php
+
+namespace Drupal\Component\Gettext;
+
+/**
+ * Common functions for file/stream based PO readers/writers.
+ *
+ * @see PoReaderInterface
+ * @see PoWriterInterface
+ */
+interface PoStreamInterface {
+
+ /**
+ * Open the stream. Set the URI for the stream earlier with setURI().
+ */
+ public function open();
+
+ /**
+ * Close the stream.
+ */
+ public function close();
+
+ /**
+ * Gets the URI of the PO stream that is being read or written.
+ *
+ * @return
+ * URI string for this stream.
+ */
+ public function getURI();
+
+ /**
+ * Set the URI of the PO stream that is going to be read or written.
+ *
+ * @param $uri
+ * URI string to set for this stream.
+ */
+ public function setURI($uri);
+
+}