1 files changed, 53 insertions, 0 deletions
diff --git a/js/src/builtin/streams/PipeToState-inl.h b/js/src/builtin/streams/PipeToState-inl.h
new file mode 100644
index 0000000000..5006185aec
--- /dev/null
+++ b/js/src/builtin/streams/PipeToState-inl.h
@@ -0,0 +1,53 @@
+/* -*- 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/. */
+
+/* ReadableStream pipe-to operation captured state. */
+
+#ifndef builtin_streams_PipeToState_inl_h
+#define builtin_streams_PipeToState_inl_h
+
+#include "builtin/streams/PipeToState.h"
+
+#include "mozilla/Assertions.h"  // MOZ_ASSERT
+#include "mozilla/Attributes.h"  // MOZ_MUST_USE
+
+#include "jstypes.h"  // JS_PUBLIC_API
+
+#include "js/RootingAPI.h"  // JS::Handle
+#include "vm/JSContext.h"   // JSContext
+#include "vm/Runtime.h"     // JSRuntime
+
+#include "vm/Compartment-inl.h"  // js::UnwrapAndDowncastValue
+#include "vm/JSContext-inl.h"    // JSContext::check
+
+struct JS_PUBLIC_API JSContext;
+class JS_PUBLIC_API JSObject;
+
+namespace js {
+
+/**
+ * Returns the unwrapped |AbortSignal| instance associated with a given pipe-to
+ * operation.
+ *
+ * The pipe-to operation must be known to have had an |AbortSignal| associated
+ * with it.
+ *
+ * If the signal is a wrapper, it will be unwrapped, so the result might not be
+ * an object from the currently active compartment.
+ */
+inline MOZ_MUST_USE JSObject* UnwrapSignalFromPipeToState(
+    JSContext* cx, JS::Handle<PipeToState*> pipeToState) {
+  cx->check(pipeToState);
+
+  MOZ_ASSERT(pipeToState->hasSignal());
+  return UnwrapAndDowncastValue(
+      cx, pipeToState->getFixedSlot(PipeToState::Slot_Signal),
+      cx->runtime()->maybeAbortSignalClass());
+}
+
+}  // namespace js
+
+#endif  // builtin_streams_PipeToState_inl_h