tor-browser

The Tor Browser
git clone https://git.dasho.dev/tor-browser.git
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FileSystemHashSource.cpp (2298B)

      1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
      2 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
      3 /* This Source Code Form is subject to the terms of the Mozilla Public
      4 * License, v. 2.0. If a copy of the MPL was not distributed with this
      5 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
      6 
      7 #include "FileSystemHashSource.h"
      8 
      9 #include "FileSystemParentTypes.h"
     10 #include "mozilla/dom/FileSystemTypes.h"
     11 #include "mozilla/dom/data_encoding_ffi_generated.h"
     12 #include "mozilla/dom/quota/QuotaCommon.h"
     13 #include "nsComponentManagerUtils.h"
     14 #include "nsICryptoHash.h"
     15 #include "nsNetCID.h"
     16 #include "nsString.h"
     17 #include "nsStringFwd.h"
     18 
     19 namespace mozilla::dom::fs::data {
     20 
     21 Result<EntryId, QMResult> FileSystemHashSource::GenerateHash(
     22    const EntryId& aParent, const Name& aName) {
     23  auto makeHasher = [](nsresult* aRv) {
     24    return do_CreateInstance(NS_CRYPTO_HASH_CONTRACTID, aRv);
     25  };
     26  QM_TRY_INSPECT(const auto& hasher,
     27                 QM_TO_RESULT_TRANSFORM(MOZ_TO_RESULT_GET_TYPED(
     28                     nsCOMPtr<nsICryptoHash>, makeHasher)));
     29 
     30  QM_TRY(QM_TO_RESULT(hasher->Init(nsICryptoHash::SHA256)));
     31 
     32  QM_TRY(QM_TO_RESULT(
     33      hasher->Update(reinterpret_cast<const uint8_t*>(aName.BeginReading()),
     34                     sizeof(char16_t) * aName.Length())));
     35 
     36  QM_TRY(QM_TO_RESULT(
     37      hasher->Update(reinterpret_cast<const uint8_t*>(aParent.BeginReading()),
     38                     aParent.Length())));
     39 
     40  EntryId entryId;
     41  QM_TRY(QM_TO_RESULT(hasher->Finish(/* aASCII */ false, entryId)));
     42  MOZ_ASSERT(!entryId.IsEmpty());
     43 
     44  return entryId;
     45 }
     46 
     47 Result<Name, QMResult> FileSystemHashSource::EncodeHash(const FileId& aFileId) {
     48  MOZ_ASSERT(32u == aFileId.Value().Length());
     49  nsCString encoded;
     50  base32encode(&aFileId.Value(), &encoded);
     51 
     52  // We are stripping last four padding characters because
     53  // it may not be allowed in some file systems.
     54  MOZ_ASSERT(56u == encoded.Length() && '=' == encoded[52u] &&
     55             '=' == encoded[53u] && '=' == encoded[54u] && '=' == encoded[55u]);
     56  encoded.SetLength(52u);
     57 
     58  Name result;
     59  QM_TRY(OkIf(result.SetCapacity(encoded.Length(), mozilla::fallible)),
     60         Err(QMResult(NS_ERROR_OUT_OF_MEMORY)));
     61 
     62  result.AppendASCII(encoded);
     63 
     64  return result;
     65 }
     66 
     67 }  // namespace mozilla::dom::fs::data