1 files changed, 69 insertions, 0 deletions
diff --git a/toolkit/components/uniffi-js/OwnedRustBuffer.h b/toolkit/components/uniffi-js/OwnedRustBuffer.h
new file mode 100644
index 0000000000..d43a233306
--- /dev/null
+++ b/toolkit/components/uniffi-js/OwnedRustBuffer.h
@@ -0,0 +1,69 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:set ts=2 sw=2 sts=2 et cindent: */
+/* 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 mozilla_OwnedRustBuffer_h
+#define mozilla_OwnedRustBuffer_h
+
+#include "mozilla/ErrorResult.h"
+#include "mozilla/ResultVariant.h"
+#include "mozilla/dom/TypedArray.h"
+#include "mozilla/dom/UniFFIRust.h"
+
+namespace mozilla::uniffi {
+
+// RustBuffer that's owned by the JS code and handles the memory management
+class OwnedRustBuffer final {
+ private:
+  RustBuffer mBuf;
+
+  void FreeData();
+
+ public:
+  // The default constructor creates an invalid OwnedRustBuffer
+  OwnedRustBuffer() : mBuf{0} {};
+
+  // Constructor for creating an OwnedRustBuffer from a raw RustBuffer struct
+  // that was returned by Rust (therefore we now own the RustBuffer).
+  explicit OwnedRustBuffer(const RustBuffer& aBuf);
+
+  // Manual implementation of move constructor and assignment operator.
+  OwnedRustBuffer(OwnedRustBuffer&& aOther);
+  OwnedRustBuffer& operator=(OwnedRustBuffer&& aOther);
+
+  // Delete copy & move constructor as this type is non-copyable.
+  OwnedRustBuffer(const OwnedRustBuffer&) = delete;
+  OwnedRustBuffer& operator=(const OwnedRustBuffer&) = delete;
+
+  // Destructor that frees the RustBuffer if it is still valid
+  ~OwnedRustBuffer();
+
+  // Constructor for creating an OwnedRustBuffer from an ArrayBuffer. Will set
+  // aError to failed and construct an invalid OwnedRustBuffer if the
+  // conversion failed.
+  static Result<OwnedRustBuffer, nsCString> FromArrayBuffer(
+      const mozilla::dom::ArrayBuffer& aArrayBuffer);
+
+  // Moves the buffer out of this `OwnedArrayBuffer` into a raw `RustBuffer`
+  // struct.  The raw struct must be passed into a Rust function, transfering
+  // ownership to Rust.  After this call the buffer will no longer be valid.
+  RustBuffer IntoRustBuffer();
+
+  // Moves the buffer out of this `OwnedArrayBuffer` into a JS ArrayBuffer.
+  // This transfers ownership into the JS engine.  After this call the buffer
+  // will no longer be valid.
+  JSObject* IntoArrayBuffer(JSContext* cx);
+
+  // Is this RustBuffer pointing to valid data?
+  bool IsValid() const { return mBuf.data != nullptr; }
+
+ private:
+  // Helper function used by IntoArrayBuffer.
+  static void ArrayBufferFreeFunc(void* contents, void* userData);
+};
+
+}  // namespace mozilla::uniffi
+
+#endif  // mozilla_OwnedRustBuffer_h