Quelle  DirectoryMetadata.cpp

/* 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 "DirectoryMetadata.h"

#include "mozilla/Result.h"
#include "mozilla/TypedEnumBits.h"
#include "mozilla/dom/quota/Assertions.h"
#include "mozilla/dom/quota/CommonMetadata.h"
#include "mozilla/dom/quota/QuotaCommon.h"
#include "mozilla/dom/quota/ResultExtensions.h"
#include "mozilla/dom/quota/StreamUtils.h"
#include "nsIBinaryInputStream.h"
#include "nsIBinaryOutputStream.h"

namespace mozilla::dom::quota {

// clang-format off

enum class DirectoryMetadataFlags : uint32_t {
  None        = 0,
  Initialized = 1 << 0,
  Accessed    = 1 << 1,
};

// clang-format on

MOZ_MAKE_ENUM_CLASS_BITWISE_OPERATORS(DirectoryMetadataFlags)

Result<OriginStateMetadata, nsresult> ReadDirectoryMetadataHeader(
    nsIBinaryInputStream& aStream) {
  AssertIsOnIOThread();

  OriginStateMetadata originStateMetadata;

  QM_TRY_UNWRAP(originStateMetadata.mLastAccessTime,
                MOZ_TO_RESULT_INVOKE_MEMBER(aStream, Read64));

  QM_TRY_UNWRAP(originStateMetadata.mPersisted,
                MOZ_TO_RESULT_INVOKE_MEMBER(aStream, ReadBoolean));

  QM_TRY_INSPECT(const uint32_t& rawFlags,
                 MOZ_TO_RESULT_INVOKE_MEMBER(aStream, Read32));

  auto flags = static_cast<DirectoryMetadataFlags>(rawFlags);

  // If DirectoryMetadataFlags::Initialized is not set, the flags field
  // contains no valid data. Since mAccessed indicates whether a full scan must
  // be done during initialization, we conservatively set it to true when the
  // access state is unknown.
  originStateMetadata.mAccessed =
      rawFlags == 0 || (flags & DirectoryMetadataFlags::Accessed) !=
                           DirectoryMetadataFlags::None;

  QM_TRY_UNWRAP(originStateMetadata.mLastMaintenanceDate,
                MOZ_TO_RESULT_INVOKE_MEMBER(aStream, Read32));

  return originStateMetadata;
}

nsresult WriteDirectoryMetadataHeader(
    nsIBinaryOutputStream& aStream,
    const OriginStateMetadata& aOriginStateMetadata) {
  AssertIsOnIOThread();

  QM_TRY(MOZ_TO_RESULT(aStream.Write64(aOriginStateMetadata.mLastAccessTime)));

  QM_TRY(MOZ_TO_RESULT(aStream.WriteBoolean(aOriginStateMetadata.mPersisted)));

  // Always set DirectoryMetadataFlags::Initialized when writing new metadata,
  // to mark the flags field as valid. This distinguishes real flags from older
  // files where the field was reserved and always written as zero.
  auto flags =
      DirectoryMetadataFlags::Initialized |
      (aOriginStateMetadata.mAccessed ? DirectoryMetadataFlags::Accessed
                                      : DirectoryMetadataFlags::None);

  auto rawFlags = static_cast<uint32_t>(flags);

  QM_TRY(MOZ_TO_RESULT(aStream.Write32(rawFlags)));

  QM_TRY(MOZ_TO_RESULT(
      aStream.Write32(aOriginStateMetadata.mLastMaintenanceDate)));

  return NS_OK;
}

Result<OriginStateMetadata, nsresult> LoadDirectoryMetadataHeader(
    nsIFile& aDirectory) {
  AssertIsOnIOThread();

  QM_TRY_INSPECT(
      const auto& stream,
      GetBinaryInputStream(aDirectory, nsLiteralString(METADATA_V2_FILE_NAME)));

  QM_TRY_INSPECT(const OriginStateMetadata& originStateMetadata,
                 ReadDirectoryMetadataHeader(*stream));

  QM_TRY(MOZ_TO_RESULT(stream->Close()));

  return originStateMetadata;
}

nsresult SaveDirectoryMetadataHeader(
    nsIFile& aDirectory, const OriginStateMetadata& aOriginStateMetadata) {
  AssertIsOnIOThread();

  QM_TRY_INSPECT(
      const auto& file,
      CloneFileAndAppend(aDirectory, nsLiteralString(METADATA_V2_FILE_NAME)));

  QM_TRY_INSPECT(const auto& stream,
                 GetBinaryOutputStream(*file, FileFlag::Update));
  MOZ_ASSERT(stream);

  QM_TRY(MOZ_TO_RESULT(
      WriteDirectoryMetadataHeader(*stream, aOriginStateMetadata)));

  QM_TRY(MOZ_TO_RESULT(stream->Flush()));

  QM_TRY(MOZ_TO_RESULT(stream->Close()));

  return NS_OK;
}

}  // namespace mozilla::dom::quota