1 files changed, 71 insertions, 0 deletions
diff --git a/js/src/builtin/streams/ReadableStreamReader-inl.h b/js/src/builtin/streams/ReadableStreamReader-inl.h
new file mode 100644
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+++ b/js/src/builtin/streams/ReadableStreamReader-inl.h
@@ -0,0 +1,71 @@
+/* -*- 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/. */
+
+#ifndef builtin_streams_ReadableStreamReader_inl_h
+#define builtin_streams_ReadableStreamReader_inl_h
+
+#include "builtin/streams/ReadableStreamReader.h"
+
+#include "mozilla/Assertions.h"  // MOZ_ASSERT
+#include "mozilla/Attributes.h"  // MOZ_MUST_USE
+
+#include "jsfriendapi.h"  // JS_IsDeadWrapper
+
+#include "builtin/streams/ReadableStream.h"  // js::ReadableStream
+#include "js/Proxy.h"                        // js::IsProxy
+#include "js/RootingAPI.h"                   // JS::Handle
+#include "vm/NativeObject.h"                 // js::NativeObject::getFixedSlot
+
+#include "vm/Compartment-inl.h"  // js::UnwrapInternalSlot
+
+namespace js {
+
+/**
+ * Returns the stream associated with the given reader.
+ */
+inline MOZ_MUST_USE ReadableStream* UnwrapStreamFromReader(
+    JSContext* cx, JS::Handle<ReadableStreamReader*> reader) {
+  MOZ_ASSERT(reader->hasStream());
+  return UnwrapInternalSlot<ReadableStream>(cx, reader,
+                                            ReadableStreamReader::Slot_Stream);
+}
+
+/**
+ * Returns the reader associated with the given stream.
+ *
+ * Must only be called on ReadableStreams that already have a reader
+ * associated with them.
+ *
+ * If the reader is a wrapper, it will be unwrapped, so the result might not be
+ * an object from the currently active compartment.
+ */
+inline MOZ_MUST_USE ReadableStreamReader* UnwrapReaderFromStream(
+    JSContext* cx, JS::Handle<ReadableStream*> stream) {
+  return UnwrapInternalSlot<ReadableStreamReader>(cx, stream,
+                                                  ReadableStream::Slot_Reader);
+}
+
+inline MOZ_MUST_USE ReadableStreamReader* UnwrapReaderFromStreamNoThrow(
+    ReadableStream* stream) {
+  JSObject* readerObj =
+      &stream->getFixedSlot(ReadableStream::Slot_Reader).toObject();
+  if (IsProxy(readerObj)) {
+    if (JS_IsDeadWrapper(readerObj)) {
+      return nullptr;
+    }
+
+    readerObj = readerObj->maybeUnwrapAs<ReadableStreamReader>();
+    if (!readerObj) {
+      return nullptr;
+    }
+  }
+
+  return &readerObj->as<ReadableStreamReader>();
+}
+
+}  // namespace js
+
+#endif  // builtin_streams_ReadableStreamReader_inl_h