TF_RandomAccessFile* file, TF_Status* status);
void NewWritableFile(const TF_Filesystem* filesystem, const char* path,
                     TF_WritableFile* file, TF_Status* status);
void NewAppendableFile(const TF_Filesystem* filesystem, const char* path,
                       TF_WritableFile* file, TF_Status* status);
void NewReadOnlyMemoryRegionFromFile(const TF_Filesystem* filesystem,

    TF_SetStatusFromIOError(status, errno, path);
    return;
  }

  file->plugin_file = new tf_writable_file::PosixFile({strdup(path), f});
  TF_SetStatus(status, TF_OK, "");
}

static void NewAppendableFile(const TF_Filesystem* filesystem, const char* path,
                              TF_WritableFile* file, TF_Status* status) {
  FILE* f = fopen(path, "a");
  if (f == nullptr) {

  std::unique_ptr<WritableFile> new_file;
  Status status = env_->NewAppendableFile(filepath, &new_file);
  EXPECT_PRED2(UnimplementedOrReturnsCode, status, Code::OK);
}

TEST_P(ModularFileSystemTest, TestAppendFileNonExisting) {
  const std::string filepath = GetURIForPath("dir_not_found/a_file");
  std::unique_ptr<WritableFile> new_file;
  Status status = env_->NewAppendableFile(filepath, &new_file);

  return StatusFromTF_Status(plugin_status.get());
}

Status ModularFileSystem::NewAppendableFile(
    const std::string& fname, TransactionToken* token,
    std::unique_ptr<WritableFile>* result) {
  if (ops_->new_appendable_file == nullptr)
    return errors::Unimplemented(tensorflow::strings::StrCat(
        "Filesystem for ", fname, " does not support NewAppendableFile()"));

  UniquePtrTo_TF_Status plugin_status(TF_NewStatus(), TF_DeleteStatus);

      std::unique_ptr<RandomAccessFile>* result) override;
  Status NewWritableFile(const std::string& fname, TransactionToken* token,
                         std::unique_ptr<WritableFile>* result) override;
  Status NewAppendableFile(const std::string& fname, TransactionToken* token,
                           std::unique_ptr<WritableFile>* result) override;
  Status NewReadOnlyMemoryRegionFromFile(
      const std::string& fname, TransactionToken* token,

  // We are responsible for freeing the pointer returned by TF_GetTempFileName
  free(temp_file_name);
  TF_VLog(3, "GcsWritableFile: %s", path);
  TF_SetStatus(status, TF_OK, "");
}

void NewAppendableFile(const TF_Filesystem* filesystem, const char* path,
                       TF_WritableFile* file, TF_Status* status) {
  std::string bucket, object;
  ParseGCSPath(path, false, &bucket, &object, status);