TF_EXPECT_OK(ReadCache(&cache, filename, 0, 16, &out));
  EXPECT_EQ(calls, 1);

  // Second read. Hit cache.
  EXPECT_TRUE(cache.ValidateAndUpdateFileSignature(filename, 123));
  TF_EXPECT_OK(ReadCache(&cache, filename, 0, 16, &out));
  EXPECT_EQ(calls, 1);

  // Third read. File signatures are different.
  EXPECT_FALSE(cache.ValidateAndUpdateFileSignature(filename, 321));

}

void RamFileBlockCache::RemoveFile(const std::string& filename) {
  absl::MutexLock lock(&mu_);
  RemoveFile_Locked(filename);
}

void RamFileBlockCache::RemoveFile_Locked(const std::string& filename) {
  Key begin = std::make_pair(filename, 0);
  auto it = block_map_.lower_bound(begin);
  while (it != block_map_.end() && it->first.first == filename) {
    auto next = std::next(it);
    RemoveBlock(it);

CheckpointReader::CheckpointReader(const string& filename, TF_Status* status)
    : reader_(nullptr),
      v2_reader_(nullptr),
      var_to_shape_map_(nullptr),
      var_to_data_type_map_(nullptr) {
  // Depending on whether this is a V2 ckpt, initializes "reader_" or
  // "v2_reader_".
  std::vector<string> v2_path;
  if (Env::Default()->GetMatchingPaths(MetaFilename(filename), &v2_path).ok() &&
      !v2_path.empty()) {

      GetURIForPath("yet_another_file"),
  };

  for (const auto& filename : matching_filenames) {
    std::unique_ptr<WritableFile> file;
    Status status = env_->NewWritableFile(filename, &file);
    if (!status.ok())
      GTEST_SKIP() << "NewWritableFile() not supported: " << status;
  }

  for (const auto& filename : other_filenames) {
    std::unique_ptr<WritableFile> file;

}

Status ModularRandomAccessFile::Name(StringPiece* result) const {
  *result = filename_;
  return OkStatus();
}

Status ModularWritableFile::Append(StringPiece data) {
  if (ops_->append == nullptr)
    return errors::Unimplemented(tensorflow::strings::StrCat(
        "Append() not implemented for ", filename_));

  UniquePtrTo_TF_Status plugin_status(TF_NewStatus(), TF_DeleteStatus);

// other languages.
//
// The class currently only interacts with single-slice (i.e., non-partitioned)
// variables.
class CheckpointReader {
 public:
  CheckpointReader(const string& filename, TF_Status* status);

  bool HasTensor(const string& name) const;
  const string DebugString() const;

  // Returns a map from variable names to their shapes.  Slices of a partitioned

typedef struct PosixFile {
  const char* filename;
  int fd;
} PosixFile;

static void Cleanup(TF_RandomAccessFile* file) {
  auto posix_file = static_cast<PosixFile*>(file->plugin_file);
  close(posix_file->fd);
  // This would be safe to free using `free` directly as it is only opaque.
  // However, it is better to be consistent everywhere.
  plugin_memory_free(const_cast<char*>(posix_file->filename));
  delete posix_file;
}

  std::vector<std::string> variable_list;
};

TF_CheckpointReader* TF_NewCheckpointReader(const char* filename,
                                            TF_Status* status) {
  TF_CheckpointReader* reader = new TF_CheckpointReader(filename, status);
  if (!status->status.ok()) {
    TF_DeleteCheckpointReader(reader);
    return nullptr;
  }

    TF_ImportGraphDefOptions* opts, unsigned char enable);

// Load the library specified by library_filename and register the pluggable
// device and related kernels present in that library. This function is not
// supported on embedded on mobile and embedded platforms and will fail if
// called.
//
// Pass "library_filename" to a platform-specific mechanism for dynamically

  *undeleted_file_count = f;
  *undeleted_dir_count = d;
}

void TF_FileStat(const char* filename, TF_FileStatistics* stats,
                 TF_Status* status) {
  ::tensorflow::FileStatistics cc_stats;
  TF_SetStatus(status, TF_OK, "");
  ::tensorflow::Status s =
      ::tensorflow::Env::Default()->Stat(filename, &cc_stats);
  ::tensorflow::Set_TF_Status_from_Status(status, s);
  if (s.ok()) {