TF_DEVICELIST_METHOD(const char*, TF_DeviceListType, device_type().c_str(),
                     nullptr);
TF_DEVICELIST_METHOD(int64_t, TF_DeviceListMemoryBytes, memory_limit(), -1);
TF_DEVICELIST_METHOD(uint64_t, TF_DeviceListIncarnation, incarnation(), 0);

#undef TF_DEVICELIST_METHOD

}  // end extern "C"

// --------------------------------------------------------------------------
// New Graph and Session API

  // However, it is better to be consistent everywhere.
  plugin_memory_free(const_cast<char*>(posix_file->filename));
  delete posix_file;
}

static int64_t Read(const TF_RandomAccessFile* file, uint64_t offset, size_t n,
                    char* buffer, TF_Status* status) {
  auto posix_file = static_cast<PosixFile*>(file->plugin_file);
  char* dst = buffer;
  int64_t read = 0;

  while (n > 0) {

}

TF_CAPI_EXPORT extern uint64_t TF_NowNanos(void) {
  return ::tensorflow::Env::Default()->NowNanos();
}

// Returns the number of microseconds since the Unix epoch.
TF_CAPI_EXPORT extern uint64_t TF_NowMicros(void) {
  return ::tensorflow::Env::Default()->NowMicros();
}

// Returns the number of seconds since the Unix epoch.
TF_CAPI_EXPORT extern uint64_t TF_NowSeconds(void) {

  return cache_size_;
}

void RamFileBlockCache::Prune() {
  while (!stop_pruning_thread_.WaitForNotificationWithTimeout(
      absl::Microseconds(1000000))) {
    absl::MutexLock lock(&mu_);
    uint64_t now = timer_seconds_();
    while (!lra_list_.empty()) {
      auto it = block_map_.find(lra_list_.back());
      if (now - it->second->timestamp <= max_staleness_) {

namespace tf_random_access_file {
using ReadFn =
    std::function<int64_t(const std::string& path, uint64_t offset, size_t n,
                          char* buffer, TF_Status* status)>;
typedef struct GCSFile {
  const std::string path;
  const bool is_cache_enable;
  const uint64_t buffer_size;
  ReadFn read_fn;
  absl::Mutex buffer_mutex;
  uint64_t buffer_start ABSL_GUARDED_BY(buffer_mutex);

                                         undeleted_dirs);

  UniquePtrTo_TF_Status plugin_status(TF_NewStatus(), TF_DeleteStatus);
  std::string translated_name = TranslateName(dirname);
  uint64_t plugin_undeleted_files, plugin_undeleted_dirs;
  ops_->delete_recursively(filesystem_.get(), translated_name.c_str(),
                           &plugin_undeleted_files, &plugin_undeleted_dirs,

  off_t offset = 0;
  int bytes_transferred = 0;
  int rc = 1;
  // When `sendfile` returns 0 we stop copying and let callers handle this.
  while (offset < size && rc > 0) {
    // Use uint64 for safe compare SSIZE_MAX
    uint64_t chunk = size - offset;
    if (chunk > SSIZE_MAX) chunk = SSIZE_MAX;

    rc = sendfile(dst_fd, src_fd, &offset, static_cast<size_t>(chunk));
    if (rc < 0) return -1;
    bytes_transferred += rc;

  if (!status.ok()) GTEST_SKIP() << "CreateDir() not supported: " << status;

  uint64 size;
  status = env_->GetFileSize(dirpath, &size);
  EXPECT_PRED2(UnimplementedOrReturnsCode, status, Code::FAILED_PRECONDITION);
}

TEST_P(ModularFileSystemTest, TestGetFileSizeNotFound) {
  const std::string filepath = GetURIForPath("a_dir");
  uint64 size;
  Status status = env_->GetFileSize(filepath, &size);

  EXPECT_EQ(value, 4);
  EXPECT_TRUE(cache2.Lookup("e", &value));
  EXPECT_EQ(value, 5);
}

TEST(ExpiringLRUCacheTest, LookupOrCompute) {
  // max_age of 0 means we should always compute.
  uint64 num_compute_calls = 0;
  tf_gcs_filesystem::ExpiringLRUCache<int>::ComputeFunc compute_func =
      [&num_compute_calls](const string& key, int* value, TF_Status* status) {
        *value = num_compute_calls;

  TF_Tensor* a =
      TF_AllocateTensor(TF_UINT64, dims, 2, 6 * TF_DataTypeSize(TF_UINT64));
  TF_Tensor* b =
      TF_AllocateTensor(TF_UINT64, nullptr, 0, TF_DataTypeSize(TF_UINT64));
  EXPECT_NE(a, nullptr);
  EXPECT_NE(b, nullptr);

  EXPECT_EQ(6, TF_TensorElementCount(a));
  EXPECT_EQ(1, TF_TensorElementCount(b));
  EXPECT_EQ(6 * TF_DataTypeSize(TF_UINT64), TF_TensorByteSize(a));