1 files changed, 92 insertions, 0 deletions
diff --git a/toolkit/components/uniffi-js/OwnedRustBuffer.cpp b/toolkit/components/uniffi-js/OwnedRustBuffer.cpp
new file mode 100644
index 0000000000..96d9dc1fd7
--- /dev/null
+++ b/toolkit/components/uniffi-js/OwnedRustBuffer.cpp
@@ -0,0 +1,92 @@
+/* -*- 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/. */
+
+#include "nsString.h"
+#include "mozilla/dom/OwnedRustBuffer.h"
+
+namespace mozilla::uniffi {
+
+using dom::ArrayBuffer;
+
+OwnedRustBuffer::OwnedRustBuffer(const RustBuffer& aBuf) {
+  mBuf = aBuf;
+  MOZ_ASSERT(IsValid());
+}
+
+Result<OwnedRustBuffer, nsCString> OwnedRustBuffer::FromArrayBuffer(
+    const ArrayBuffer& aArrayBuffer) {
+  if (aArrayBuffer.Length() > INT32_MAX) {
+    return Err("Input ArrayBuffer is too large"_ns);
+  }
+
+  RustCallStatus status{};
+  RustBuffer buf = uniffi_rustbuffer_alloc(
+      static_cast<int32_t>(aArrayBuffer.Length()), &status);
+  buf.len = aArrayBuffer.Length();
+  if (status.code != 0) {
+    if (status.error_buf.data) {
+      auto message = nsCString("uniffi_rustbuffer_alloc: ");
+      message.Append(
+          nsDependentCSubstring(reinterpret_cast<char*>(status.error_buf.data),
+                                status.error_buf.len));
+      RustCallStatus status2{};
+      uniffi_rustbuffer_free(status.error_buf, &status2);
+      MOZ_RELEASE_ASSERT(status2.code == 0,
+                         "Freeing a rustbuffer should never fail");
+      return Err(message);
+
+    } else {
+      return Err("Unknown error allocating rust buffer"_ns);
+    }
+  }
+
+  memcpy(buf.data, aArrayBuffer.Data(), buf.len);
+  return OwnedRustBuffer(buf);
+}
+
+OwnedRustBuffer::OwnedRustBuffer(OwnedRustBuffer&& aOther) : mBuf(aOther.mBuf) {
+  aOther.mBuf = RustBuffer{0};
+}
+
+OwnedRustBuffer& OwnedRustBuffer::operator=(OwnedRustBuffer&& aOther) {
+  if (&aOther != this) {
+    FreeData();
+  }
+  mBuf = aOther.mBuf;
+  aOther.mBuf = RustBuffer{0};
+  return *this;
+}
+
+void OwnedRustBuffer::FreeData() {
+  if (IsValid()) {
+    RustCallStatus status{};
+    uniffi_rustbuffer_free(mBuf, &status);
+    MOZ_RELEASE_ASSERT(status.code == 0,
+                       "Freeing a rustbuffer should never fail");
+    mBuf = {0};
+  }
+}
+
+OwnedRustBuffer::~OwnedRustBuffer() { FreeData(); }
+
+RustBuffer OwnedRustBuffer::IntoRustBuffer() {
+  RustBuffer rv = mBuf;
+  mBuf = {};
+  return rv;
+}
+
+JSObject* OwnedRustBuffer::IntoArrayBuffer(JSContext* cx) {
+  int32_t len = mBuf.len;
+  void* data = mBuf.data;
+  auto userData = MakeUnique<OwnedRustBuffer>(std::move(*this));
+  return JS::NewExternalArrayBuffer(cx, len, data, &ArrayBufferFreeFunc,
+                                    userData.release());
+}
+
+void OwnedRustBuffer::ArrayBufferFreeFunc(void* contents, void* userData) {
+  UniquePtr<OwnedRustBuffer> buf{reinterpret_cast<OwnedRustBuffer*>(userData)};
+}
+}  // namespace mozilla::uniffi