1 files changed, 67 insertions, 0 deletions
diff --git a/dom/fs/parent/FileSystemHashSource.cpp b/dom/fs/parent/FileSystemHashSource.cpp
new file mode 100644
index 0000000000..eb43575371
--- /dev/null
+++ b/dom/fs/parent/FileSystemHashSource.cpp
@@ -0,0 +1,67 @@
+/* -*- 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 "FileSystemHashSource.h"
+
+#include "mozilla/dom/FileSystemTypes.h"
+#include "mozilla/dom/data_encoding_ffi_generated.h"
+#include "mozilla/dom/quota/QuotaCommon.h"
+#include "nsComponentManagerUtils.h"
+#include "nsICryptoHash.h"
+#include "nsNetCID.h"
+#include "nsString.h"
+#include "nsStringFwd.h"
+
+namespace mozilla::dom::fs::data {
+
+Result<EntryId, QMResult> FileSystemHashSource::GenerateHash(
+    const EntryId& aParent, const Name& aName) {
+  auto makeHasher = [](nsresult* aRv) {
+    return do_CreateInstance(NS_CRYPTO_HASH_CONTRACTID, aRv);
+  };
+  QM_TRY_INSPECT(const auto& hasher,
+                 QM_TO_RESULT_TRANSFORM(MOZ_TO_RESULT_GET_TYPED(
+                     nsCOMPtr<nsICryptoHash>, makeHasher)));
+
+  QM_TRY(QM_TO_RESULT(hasher->Init(nsICryptoHash::SHA256)));
+
+  QM_TRY(QM_TO_RESULT(
+      hasher->Update(reinterpret_cast<const uint8_t*>(aName.BeginReading()),
+                     sizeof(char16_t) * aName.Length())));
+
+  QM_TRY(QM_TO_RESULT(
+      hasher->Update(reinterpret_cast<const uint8_t*>(aParent.BeginReading()),
+                     aParent.Length())));
+
+  EntryId entryId;
+  QM_TRY(QM_TO_RESULT(hasher->Finish(/* aASCII */ false, entryId)));
+  MOZ_ASSERT(!entryId.IsEmpty());
+
+  return entryId;
+}
+
+Result<Name, QMResult> FileSystemHashSource::EncodeHash(
+    const EntryId& aEntryId) {
+  MOZ_ASSERT(32u == aEntryId.Length());
+  nsCString encoded;
+  base32encode(&aEntryId, &encoded);
+
+  // We are stripping last four padding characters because
+  // it may not be allowed in some file systems.
+  MOZ_ASSERT(56u == encoded.Length() && '=' == encoded[52u] &&
+             '=' == encoded[53u] && '=' == encoded[54u] && '=' == encoded[55u]);
+  encoded.SetLength(52u);
+
+  Name result;
+  QM_TRY(OkIf(result.SetCapacity(encoded.Length(), mozilla::fallible)),
+         Err(QMResult(NS_ERROR_OUT_OF_MEMORY)));
+
+  result.AppendASCII(encoded);
+
+  return result;
+}
+
+}  // namespace mozilla::dom::fs::data