1 files changed, 42 insertions, 0 deletions
diff --git a/xpcom/io/nsIInputStreamTee.idl b/xpcom/io/nsIInputStreamTee.idl
new file mode 100644
index 0000000000..60881e0fb8
--- /dev/null
+++ b/xpcom/io/nsIInputStreamTee.idl
@@ -0,0 +1,42 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsIInputStream.idl"
+
+interface nsIOutputStream;
+interface nsIEventTarget;
+
+/**
+ * A nsIInputStreamTee is a wrapper for an input stream, that when read
+ * reads the specified amount of data from its |source| and copies that
+ * data to its |sink|.  |sink| must be a blocking output stream.
+ */
+[scriptable, builtinclass, uuid(90a9d790-3bca-421e-a73b-98f68e13c917)]
+interface nsIInputStreamTee : nsIInputStream
+{
+    attribute nsIInputStream source;
+    attribute nsIOutputStream sink;
+
+    /**
+     * If |eventTarget| is set, copying to sink is done asynchronously using
+     * the event-target (e.g. a thread). If |eventTarget| is not set, copying
+     * to sink happens synchronously while reading from the source.
+     */
+    attribute nsIEventTarget eventTarget;
+};
+
+%{C++
+// factory methods
+extern nsresult
+NS_NewInputStreamTee(nsIInputStream **tee, // read from this input stream
+                     nsIInputStream *source,
+                     nsIOutputStream *sink);
+
+extern nsresult
+NS_NewInputStreamTeeAsync(nsIInputStream **tee, // read from this input stream
+                     nsIInputStream *source,
+                     nsIOutputStream *sink,
+                     nsIEventTarget *eventTarget);
+%}