1 files changed, 52 insertions, 0 deletions
diff --git a/js/src/builtin/streams/TeeState.cpp b/js/src/builtin/streams/TeeState.cpp
new file mode 100644
index 0000000000..c8c151fd8a
--- /dev/null
+++ b/js/src/builtin/streams/TeeState.cpp
@@ -0,0 +1,52 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: set ts=8 sts=2 et sw=2 tw=80:
+ * 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/. */
+
+/* Stream teeing state. */
+
+#include "builtin/streams/TeeState.h"
+
+#include "builtin/streams/ReadableStream.h"  // js::ReadableStream
+#include "js/Class.h"          // JSClass, JSCLASS_HAS_RESERVED_SLOTS
+#include "js/RootingAPI.h"     // JS::Handle, JS::Rooted
+#include "vm/JSContext.h"      // JSContext
+#include "vm/PromiseObject.h"  // js::PromiseObject
+
+#include "vm/JSObject-inl.h"  // js::NewBuiltinClassInstance
+
+using js::ReadableStream;
+using js::TeeState;
+
+using JS::Handle;
+using JS::Int32Value;
+using JS::ObjectValue;
+using JS::Rooted;
+
+/* static */ TeeState* TeeState::create(
+    JSContext* cx, Handle<ReadableStream*> unwrappedStream) {
+  Rooted<TeeState*> state(cx, NewBuiltinClassInstance<TeeState>(cx));
+  if (!state) {
+    return nullptr;
+  }
+
+  Rooted<PromiseObject*> cancelPromise(
+      cx, PromiseObject::createSkippingExecutor(cx));
+  if (!cancelPromise) {
+    return nullptr;
+  }
+
+  state->setFixedSlot(Slot_Flags, Int32Value(0));
+  state->setFixedSlot(Slot_CancelPromise, ObjectValue(*cancelPromise));
+  Rooted<JSObject*> wrappedStream(cx, unwrappedStream);
+  if (!cx->compartment()->wrap(cx, &wrappedStream)) {
+    return nullptr;
+  }
+  state->setFixedSlot(Slot_Stream, JS::ObjectValue(*wrappedStream));
+
+  return state;
+}
+
+const JSClass TeeState::class_ = {"TeeState",
+                                  JSCLASS_HAS_RESERVED_SLOTS(SlotCount)};