1 files changed, 87 insertions, 0 deletions
diff --git a/dom/quota/StreamUtils.cpp b/dom/quota/StreamUtils.cpp
new file mode 100644
index 0000000000..cc68577772
--- /dev/null
+++ b/dom/quota/StreamUtils.cpp
@@ -0,0 +1,87 @@
+/* -*- 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/. */
+
+#include "StreamUtils.h"
+
+#include "mozilla/Result.h"
+#include "mozilla/dom/quota/Assertions.h"
+#include "mozilla/dom/quota/QuotaCommon.h"
+#include "mozilla/dom/quota/ResultExtensions.h"
+#include "nsCOMPtr.h"
+#include "nsIFile.h"
+#include "nsIObjectInputStream.h"
+#include "nsIObjectOutputStream.h"
+#include "nsIOutputStream.h"
+#include "nsIRandomAccessStream.h"
+#include "nsNetUtil.h"
+
+namespace mozilla::dom::quota {
+
+Result<nsCOMPtr<nsIOutputStream>, nsresult> GetOutputStream(
+    nsIFile& aFile, FileFlag aFileFlag) {
+  AssertIsOnIOThread();
+
+  switch (aFileFlag) {
+    case FileFlag::Truncate:
+      QM_TRY_RETURN(NS_NewLocalFileOutputStream(&aFile));
+
+    case FileFlag::Update: {
+      QM_TRY_INSPECT(const bool& exists,
+                     MOZ_TO_RESULT_INVOKE_MEMBER(&aFile, Exists));
+
+      if (!exists) {
+        return nsCOMPtr<nsIOutputStream>();
+      }
+
+      QM_TRY_INSPECT(const auto& stream,
+                     NS_NewLocalFileRandomAccessStream(&aFile));
+
+      nsCOMPtr<nsIOutputStream> outputStream = do_QueryInterface(stream);
+      QM_TRY(OkIf(outputStream), Err(NS_ERROR_FAILURE));
+
+      return outputStream;
+    }
+
+    case FileFlag::Append:
+      QM_TRY_RETURN(NS_NewLocalFileOutputStream(
+          &aFile, PR_WRONLY | PR_CREATE_FILE | PR_APPEND));
+
+    default:
+      MOZ_CRASH("Should never get here!");
+  }
+}
+
+Result<nsCOMPtr<nsIBinaryOutputStream>, nsresult> GetBinaryOutputStream(
+    nsIFile& aFile, FileFlag aFileFlag) {
+  QM_TRY_UNWRAP(auto outputStream, GetOutputStream(aFile, aFileFlag));
+
+  QM_TRY(OkIf(outputStream), Err(NS_ERROR_UNEXPECTED));
+
+  return nsCOMPtr<nsIBinaryOutputStream>(
+      NS_NewObjectOutputStream(outputStream));
+}
+
+Result<nsCOMPtr<nsIBinaryInputStream>, nsresult> GetBinaryInputStream(
+    nsIFile& aDirectory, const nsAString& aFilename) {
+  MOZ_ASSERT(!NS_IsMainThread());
+
+  QM_TRY_INSPECT(const auto& file, MOZ_TO_RESULT_INVOKE_MEMBER_TYPED(
+                                       nsCOMPtr<nsIFile>, aDirectory, Clone));
+
+  QM_TRY(MOZ_TO_RESULT(file->Append(aFilename)));
+
+  QM_TRY_UNWRAP(auto stream, NS_NewLocalFileInputStream(file));
+
+  QM_TRY_INSPECT(const auto& bufferedStream,
+                 NS_NewBufferedInputStream(stream.forget(), 512));
+
+  QM_TRY(OkIf(bufferedStream), Err(NS_ERROR_FAILURE));
+
+  return nsCOMPtr<nsIBinaryInputStream>(
+      NS_NewObjectInputStream(bufferedStream));
+}
+
+}  // namespace mozilla::dom::quota