Class Client (2.32.0-rc)

  namespace gcs = ::google::cloud::storage;
  [](std::string const& bucket_name, std::string const& object_name) {
    auto client = gcs::Client();
    PerformSomeOperations(client, bucket_name, object_name);
  }

  namespace gcs = ::google::cloud::storage;
  using ::google::cloud::Options;
  using ::google::cloud::UnifiedCredentialsOption;
  [](std::string const& bucket_name, std::string const& object_name) {
    auto client = gcs::Client(Options{}.set<UnifiedCredentialsOption>(
        google::cloud::MakeGoogleDefaultCredentials()));
    PerformSomeOperations(client, bucket_name, object_name);
  }

  namespace gcs = ::google::cloud::storage;
  [](std::string const& filename, std::string const& bucket_name,
     std::string const& object_name) {
    auto is = std::ifstream(filename);
    is.exceptions(std::ios::badbit);
    auto json_string =
        std::string(std::istreambuf_iterator<char>(is.rdbuf()), {});
    auto credentials =
        google::cloud::MakeServiceAccountCredentials(json_string);
    auto client = gcs::Client(
        google::cloud::Options{}.set<google::cloud::UnifiedCredentialsOption>(
            credentials));
    PerformSomeOperations(client, bucket_name, object_name);
  }

namespace gcs = google::cloud::storage;
gcs::Client client = ...;
google::cloud::StatusOr<gcs::BucketMetadata> bucket_metadata =
    client.GetBucketMetadata("my-bucket");

if (!bucket_metadata) {
  std::cerr << "Error getting metadata for my-bucket: "
            << bucket_metadata.status() << "\n";
  return;
}

// Use bucket_metadata as a smart pointer here, e.g.:
std::cout << "The generation for " << bucket_metadata->name() " is "
          << bucket_metadata->generation() << "\n";

auto stream = gcs.ReadObject("my-bucket", "my-object");

auto stream = gcs.ReadObject(
    "my-bucket", "my-object", gcs::Generation(generation));

  namespace g = ::google::cloud;
  namespace gcs = ::google::cloud::storage;
  [](std::string const& bucket_name, std::string const& object_name_1,
     std::string const& object_name_2) {
    auto client = gcs::Client();
    auto metadata = client.InsertObject(
        bucket_name, object_name_1,
        "The quick brown fox jumps over the lazy dog",
        g::Options{}.set<gcs::RetryPolicyOption>(
            gcs::LimitedTimeRetryPolicy(std::chrono::minutes(5)).clone()));
    if (!metadata) throw std::move(metadata).status();

    auto is =
        client.ReadObject(bucket_name, object_name_1,
                          g::Options{}.set<gcs::RetryPolicyOption>(
                              gcs::LimitedErrorCountRetryPolicy(10).clone()));
    auto contents = std::string{std::istreambuf_iterator<char>(is.rdbuf()), {}};
    if (is.bad()) throw google::cloud::Status(is.status());

    auto os = client.WriteObject(
        bucket_name, object_name_2,
        g::Options{}.set<gcs::RetryPolicyOption>(
            gcs::LimitedTimeRetryPolicy(std::chrono::minutes(5)).clone()));
    os << contents;
    os.Close();
    if (os.bad()) throw google::cloud::Status(os.metadata().status());

    auto result = client.DeleteObject(
        bucket_name, object_name_1, gcs::Generation(metadata->generation()),
        g::Options{}.set<gcs::RetryPolicyOption>(
            gcs::LimitedErrorCountRetryPolicy(12).clone()));
    if (!result.ok()) throw std::move(metadata).status();

    metadata = os.metadata();
    result = client.DeleteObject(
        bucket_name, object_name_2, gcs::Generation(metadata->generation()),
        g::Options{}.set<gcs::RetryPolicyOption>(
            gcs::LimitedErrorCountRetryPolicy(12).clone()));
    if (!result.ok()) throw std::move(metadata).status();
  }

  namespace gcs = ::google::cloud::storage;
  using ::google::cloud::StatusOr;
  [](std::string const& bucket_name, std::string const& object_name,
     std::string const& contents) {
    // Create a client that only retries idempotent operations, the default is
    // to retry all operations.
    auto client =
        gcs::Client(google::cloud::Options{}.set<gcs::IdempotencyPolicyOption>(
            gcs::StrictIdempotencyPolicy().clone()));
    StatusOr<gcs::ObjectMetadata> object_metadata =
        client.InsertObject(bucket_name, object_name, std::move(contents),
                            gcs::IfGenerationMatch(0));
    if (!object_metadata) throw std::move(object_metadata).status();

    std::cout << "The object " << object_metadata->name()
              << " was created in bucket " << object_metadata->bucket()
              << "\nFull metadata: " << *object_metadata << "\n";
  }

  namespace gcs = ::google::cloud::storage;
  using ::google::cloud::StatusOr;
  [](std::string const& bucket_name, std::string const& object_name,
     std::string const& contents) {
    // Create a client that only gives up on the third error. The default policy
    // is to retry for several minutes.
    auto client =
        gcs::Client(google::cloud::Options{}.set<gcs::RetryPolicyOption>(
            gcs::LimitedErrorCountRetryPolicy(3).clone()));

    StatusOr<gcs::ObjectMetadata> object_metadata =
        client.InsertObject(bucket_name, object_name, std::move(contents),
                            gcs::IfGenerationMatch(0));
    if (!object_metadata) throw std::move(object_metadata).status();

    std::cout << "The object " << object_metadata->name()
              << " was created in bucket " << object_metadata->bucket()
              << "\nFull metadata: " << *object_metadata << "\n";
  }

  namespace gcs = ::google::cloud::storage;
  [](std::string const& filename, std::string const& bucket_name,
     std::string const& object_name) {
    auto is = std::ifstream(filename);
    is.exceptions(std::ios::badbit);
    auto json_string =
        std::string(std::istreambuf_iterator<char>(is.rdbuf()), {});
    auto credentials =
        google::cloud::MakeServiceAccountCredentials(json_string);
    auto client = gcs::Client(
        google::cloud::Options{}.set<google::cloud::UnifiedCredentialsOption>(
            credentials));
    PerformSomeOperations(client, bucket_name, object_name);
  }

  namespace gcs = ::google::cloud::storage;
  [](gcs::Client client, std::string const& project_id) {
    int count = 0;
    for (auto&& bucket_metadata : client.ListBucketsForProject(project_id)) {
      if (!bucket_metadata) throw std::move(bucket_metadata).status();

      std::cout << bucket_metadata->name() << "\n";
      ++count;
    }

    if (count == 0) {
      std::cout << "No buckets in project " << project_id << "\n";
    }
  }

  namespace gcs = ::google::cloud::storage;
  using ::google::cloud::StatusOr;
  [](gcs::Client client) {
    int count = 0;
    gcs::ListBucketsReader bucket_list = client.ListBuckets();
    for (auto&& bucket_metadata : bucket_list) {
      if (!bucket_metadata) throw std::move(bucket_metadata).status();

      std::cout << bucket_metadata->name() << "\n";
      ++count;
    }

    if (count == 0) {
      std::cout << "No buckets in default project\n";
    }
  }

  namespace gcs = ::google::cloud::storage;
  using ::google::cloud::StatusOr;
  [](gcs::Client client, std::string const& bucket_name) {
    StatusOr<gcs::BucketMetadata> bucket_metadata =
        client.CreateBucket(bucket_name, gcs::BucketMetadata());
    if (!bucket_metadata) throw std::move(bucket_metadata).status();

    std::cout << "Bucket " << bucket_metadata->name() << " created."
              << "\nFull Metadata: " << *bucket_metadata << "\n";
  }

  namespace gcs = ::google::cloud::storage;
  using ::google::cloud::StatusOr;
  [](gcs::Client client, std::string const& bucket_name,
     std::string const& project_id) {
    StatusOr<gcs::BucketMetadata> bucket_metadata =
        client.CreateBucketForProject(bucket_name, project_id,
                                      gcs::BucketMetadata{});
    if (!bucket_metadata) throw std::move(bucket_metadata).status();

    std::cout << "Bucket " << bucket_metadata->name() << " created for project "
              << project_id << " [" << bucket_metadata->project_number() << "]"
              << "\nFull Metadata: " << *bucket_metadata << "\n";
  }

  // [START storage_get_bucket_metadata]
  namespace gcs = ::google::cloud::storage;
  using ::google::cloud::StatusOr;
  [](gcs::Client client, std::string const& bucket_name) {
    StatusOr<gcs::BucketMetadata> bucket_metadata =
        client.GetBucketMetadata(bucket_name);
    if (!bucket_metadata) throw std::move(bucket_metadata).status();

    std::cout << "The metadata for bucket " << bucket_metadata->name() << " is "
              << *bucket_metadata << "\n";
  }
  // [END storage_get_bucket_metadata]

  namespace gcs = ::google::cloud::storage;
  [](gcs::Client client, std::string const& bucket_name) {
    google::cloud::Status status = client.DeleteBucket(bucket_name);
    if (!status.ok()) throw std::runtime_error(status.message());

    std::cout << "The bucket " << bucket_name << " was deleted successfully.\n";
  }

  namespace gcs = ::google::cloud::storage;
  using ::google::cloud::StatusOr;
  [](gcs::Client client, std::string const& bucket_name,
     std::string const& storage_class) {
    StatusOr<gcs::BucketMetadata> meta = client.GetBucketMetadata(bucket_name);
    if (!meta) throw std::move(meta).status();

    meta->set_storage_class(storage_class);
    StatusOr<gcs::BucketMetadata> updated =
        client.UpdateBucket(bucket_name, *meta);
    if (!updated) throw std::move(updated).status();

    std::cout << "Updated the storage class in " << updated->name() << " to "
              << updated->storage_class() << "."
              << "\nFull metadata:" << *updated << "\n";
  }

  namespace gcs = ::google::cloud::storage;
  using ::google::cloud::StatusOr;
  [](gcs::Client client, std::string const& bucket_name,
     std::string const& storage_class) {
    StatusOr<gcs::BucketMetadata> original =
        client.GetBucketMetadata(bucket_name);
    if (!original) throw std::move(original).status();

    gcs::BucketMetadata desired = *original;
    desired.set_storage_class(storage_class);

    StatusOr<gcs::BucketMetadata> patched =
        client.PatchBucket(bucket_name, *original, desired);
    if (!patched) throw std::move(patched).status();

    std::cout << "Storage class for bucket " << patched->name()
              << " has been patched to " << patched->storage_class() << "."
              << "\nFull metadata: " << *patched << "\n";
  }

  namespace gcs = ::google::cloud::storage;
  using ::google::cloud::StatusOr;
  [](gcs::Client client, std::string const& bucket_name,
     std::string const& storage_class) {
    StatusOr<gcs::BucketMetadata> patched = client.PatchBucket(
        bucket_name,
        gcs::BucketMetadataPatchBuilder().SetStorageClass(storage_class));
    if (!patched) throw std::move(patched).status();

    std::cout << "Storage class for bucket " << patched->name()
              << " has been patched to " << patched->storage_class() << "."
              << "\nFull metadata: " << *patched << "\n";
  }

  namespace gcs = ::google::cloud::storage;
  using ::google::cloud::StatusOr;
  [](gcs::Client client, std::string const& bucket_name) {
    auto policy = client.GetNativeBucketIamPolicy(
        bucket_name, gcs::RequestedPolicyVersion(3));

    if (!policy) throw std::move(policy).status();
    std::cout << "The IAM policy for bucket " << bucket_name << " is "
              << *policy << "\n";
  }

  namespace gcs = ::google::cloud::storage;
  using ::google::cloud::StatusOr;
  [](gcs::Client client, std::string const& bucket_name,
     std::string const& role, std::string const& member) {
    auto policy = client.GetNativeBucketIamPolicy(
        bucket_name, gcs::RequestedPolicyVersion(3));

    if (!policy) throw std::move(policy).status();

    policy->set_version(3);
    for (auto& binding : policy->bindings()) {
      if (binding.role() != role || binding.has_condition()) {
        continue;
      }
      auto& members = binding.members();
      if (std::find(members.begin(), members.end(), member) == members.end()) {
        members.emplace_back(member);
      }
    }

    auto updated = client.SetNativeBucketIamPolicy(bucket_name, *policy);
    if (!updated) throw std::move(updated).status();

    std::cout << "Updated IAM policy bucket " << bucket_name
              << ". The new policy is " << *updated << "\n";
  }

  namespace gcs = ::google::cloud::storage;
  using ::google::cloud::StatusOr;
  [](gcs::Client client, std::string const& bucket_name,
     std::string const& role, std::string const& member) {
    auto policy = client.GetNativeBucketIamPolicy(
        bucket_name, gcs::RequestedPolicyVersion(3));
    if (!policy) throw std::move(policy).status();

    policy->set_version(3);
    std::vector<google::cloud::storage::NativeIamBinding> updated_bindings;
    for (auto& binding : policy->bindings()) {
      auto& members = binding.members();
      if (binding.role() == role && !binding.has_condition()) {
        members.erase(std::remove(members.begin(), members.end(), member),
                      members.end());
      }
      if (!members.empty()) {
        updated_bindings.emplace_back(std::move(binding));
      }
    }
    policy->bindings() = std::move(updated_bindings);

    auto updated = client.SetNativeBucketIamPolicy(bucket_name, *policy);
    if (!updated) throw std::move(updated).status();

    std::cout << "Updated IAM policy bucket " << bucket_name
              << ". The new policy is " << *updated << "\n";
  }

  namespace gcs = ::google::cloud::storage;
  using ::google::cloud::StatusOr;
  [](gcs::Client client, std::string const& bucket_name,
     std::vector<std::string> const& permissions) {
    StatusOr<std::vector<std::string>> actual_permissions =
        client.TestBucketIamPermissions(bucket_name, permissions);
    if (!actual_permissions) throw std::move(actual_permissions).status();

    if (actual_permissions->empty()) {
      std::cout << "The caller does not hold any of the tested permissions the"
                << " bucket " << bucket_name << "\n";
      return;
    }

    std::cout << "The caller is authorized for the following permissions on "
              << bucket_name << ": ";
    for (auto const& permission : *actual_permissions) {
      std::cout << "\n    " << permission;
    }
    std::cout << "\n";
  }

  // [START storage_lock_retention_policy]
  namespace gcs = ::google::cloud::storage;
  using ::google::cloud::StatusOr;
  [](gcs::Client client, std::string const& bucket_name) {
    StatusOr<gcs::BucketMetadata> original =
        client.GetBucketMetadata(bucket_name);
    if (!original) throw std::move(original).status();

    StatusOr<gcs::BucketMetadata> updated_metadata =
        client.LockBucketRetentionPolicy(bucket_name,
                                         original->metageneration());
    if (!updated_metadata) throw std::move(updated_metadata).status();

    if (!updated_metadata->has_retention_policy()) {
      std::cerr << "The bucket " << updated_metadata->name()
                << " does not have a retention policy, even though the"
                << " operation to set it was successful.\n"
                << "This is unexpected, and may indicate that another"
                << " application has modified the bucket concurrently.\n";
      return;
    }

    std::cout << "Retention policy successfully locked for bucket "
              << updated_metadata->name() << "\nNew retention policy is: "
              << updated_metadata->retention_policy()
              << "\nFull metadata: " << *updated_metadata << "\n";
  }
  // [END storage_lock_retention_policy]

  // [START storage_get_retention_policy]
  namespace gcs = ::google::cloud::storage;
  using ::google::cloud::StatusOr;
  [](gcs::Client client, std::string const& bucket_name) {
    StatusOr<gcs::BucketMetadata> bucket_metadata =
        client.GetBucketMetadata(bucket_name);
    if (!bucket_metadata) throw std::move(bucket_metadata).status();

    if (!bucket_metadata->has_retention_policy()) {
      std::cout << "The bucket " << bucket_metadata->name()
                << " does not have a retention policy set.\n";
      return;
    }

    std::cout << "The bucket " << bucket_metadata->name()
              << " retention policy is set to "
              << bucket_metadata->retention_policy() << "\n";
  }
  // [END storage_get_retention_policy]

  // [START storage_set_retention_policy]
  namespace gcs = ::google::cloud::storage;
  using ::google::cloud::StatusOr;
  [](gcs::Client client, std::string const& bucket_name,
     std::chrono::seconds period) {
    StatusOr<gcs::BucketMetadata> original =
        client.GetBucketMetadata(bucket_name);
    if (!original) throw std::move(original).status();

    StatusOr<gcs::BucketMetadata> patched = client.PatchBucket(
        bucket_name,
        gcs::BucketMetadataPatchBuilder().SetRetentionPolicy(period),
        gcs::IfMetagenerationMatch(original->metageneration()));
    if (!patched) throw std::move(patched).status();

    if (!patched->has_retention_policy()) {
      std::cout << "The bucket " << patched->name()
                << " does not have a retention policy set.\n";
      return;
    }

    std::cout << "The bucket " << patched->name()
              << " retention policy is set to " << patched->retention_policy()
              << "\n";
  }
  // [END storage_set_retention_policy]

  // [START storage_remove_retention_policy]
  namespace gcs = ::google::cloud::storage;
  using ::google::cloud::StatusOr;
  [](gcs::Client client, std::string const& bucket_name) {
    StatusOr<gcs::BucketMetadata> original =
        client.GetBucketMetadata(bucket_name);
    if (!original) throw std::move(original).status();

    StatusOr<gcs::BucketMetadata> patched = client.PatchBucket(
        bucket_name, gcs::BucketMetadataPatchBuilder().ResetRetentionPolicy(),
        gcs::IfMetagenerationMatch(original->metageneration()));
    if (!patched) throw std::move(patched).status();

    if (!patched->has_retention_policy()) {
      std::cout << "The bucket " << patched->name()
                << " does not have a retention policy set.\n";
      return;
    }

    std::cout << "The bucket " << patched->name()
              << " retention policy is set to " << patched->retention_policy()
              << ". This is unexpected, maybe a concurrent change by another"
              << " application?\n";
  }
  // [END storage_remove_retention_policy]

  namespace gcs = ::google::cloud::storage;
  using ::google::cloud::StatusOr;
  [](gcs::Client client, std::string const& bucket_name,
     std::string const& object_name, std::string const& contents) {
    StatusOr<gcs::ObjectMetadata> object_metadata =
        client.InsertObject(bucket_name, object_name, std::move(contents));
    if (!object_metadata) throw std::move(object_metadata).status();

    std::cout << "The object " << object_metadata->name()
              << " was created in bucket " << object_metadata->bucket()
              << "\nFull metadata: " << *object_metadata << "\n";
  }

  namespace gcs = ::google::cloud::storage;
  using ::google::cloud::StatusOr;
  [](gcs::Client client, std::string const& bucket_name,
     std::string const& object_name, std::string const& content_type,
     std::string const& contents) {
    // Setting the object metadata (via the `gcs::WithObjectMadata` option)
    // requires a multipart upload, the library prefers simple uploads unless
    // required as in this case.
    StatusOr<gcs::ObjectMetadata> object_metadata = client.InsertObject(
        bucket_name, object_name, std::move(contents),
        gcs::WithObjectMetadata(
            gcs::ObjectMetadata().set_content_type(content_type)));
    if (!object_metadata) throw std::move(object_metadata).status();

    std::cout << "The object " << object_metadata->name()
              << " was created in bucket " << object_metadata->bucket()
              << "\nThe contentType was set to "
              << object_metadata->content_type()
              << "\nFull metadata: " << *object_metadata << "\n";
  }

  namespace gcs = ::google::cloud::storage;
  using ::google::cloud::StatusOr;
  [](gcs::Client client, std::string const& bucket_name,
     std::string const& object_name, std::string const& contents) {
    StatusOr<gcs::ObjectMetadata> object_metadata =
        client.InsertObject(bucket_name, object_name, std::move(contents));
    if (!object_metadata) throw std::move(object_metadata).status();

    std::cout << "The object " << object_metadata->name()
              << " was created in bucket " << object_metadata->bucket()
              << "\nFull metadata: " << *object_metadata << "\n";
  }

  namespace gcs = ::google::cloud::storage;
  using ::google::cloud::StatusOr;
  [](gcs::Client client, std::string const& bucket_name,
     std::string const& object_name, std::string const& content_type,
     std::string const& contents) {
    // Setting the object metadata (via the `gcs::WithObjectMadata` option)
    // requires a multipart upload, the library prefers simple uploads unless
    // required as in this case.
    StatusOr<gcs::ObjectMetadata> object_metadata = client.InsertObject(
        bucket_name, object_name, std::move(contents),
        gcs::WithObjectMetadata(
            gcs::ObjectMetadata().set_content_type(content_type)));
    if (!object_metadata) throw std::move(object_metadata).status();

    std::cout << "The object " << object_metadata->name()
              << " was created in bucket " << object_metadata->bucket()
              << "\nThe contentType was set to "
              << object_metadata->content_type()
              << "\nFull metadata: " << *object_metadata << "\n";
  }

  namespace gcs = ::google::cloud::storage;
  using ::google::cloud::StatusOr;
  [](gcs::Client client, std::string const& bucket_name,
     std::string const& object_name, std::string const& contents) {
    StatusOr<gcs::ObjectMetadata> object_metadata =
        client.InsertObject(bucket_name, object_name, std::move(contents));
    if (!object_metadata) throw std::move(object_metadata).status();

    std::cout << "The object " << object_metadata->name()
              << " was created in bucket " << object_metadata->bucket()
              << "\nFull metadata: " << *object_metadata << "\n";
  }

  namespace gcs = ::google::cloud::storage;
  using ::google::cloud::StatusOr;
  [](gcs::Client client, std::string const& bucket_name,
     std::string const& object_name, std::string const& content_type,
     std::string const& contents) {
    // Setting the object metadata (via the `gcs::WithObjectMadata` option)
    // requires a multipart upload, the library prefers simple uploads unless
    // required as in this case.
    StatusOr<gcs::ObjectMetadata> object_metadata = client.InsertObject(
        bucket_name, object_name, std::move(contents),
        gcs::WithObjectMetadata(
            gcs::ObjectMetadata().set_content_type(content_type)));
    if (!object_metadata) throw std::move(object_metadata).status();

    std::cout << "The object " << object_metadata->name()
              << " was created in bucket " << object_metadata->bucket()
              << "\nThe contentType was set to "
              << object_metadata->content_type()
              << "\nFull metadata: " << *object_metadata << "\n";
  }

  namespace gcs = ::google::cloud::storage;
  using ::google::cloud::StatusOr;
  [](gcs::Client client, std::string const& source_bucket_name,
     std::string const& source_object_name,
     std::string const& destination_bucket_name,
     std::string const& destination_object_name) {
    StatusOr<gcs::ObjectMetadata> new_copy_meta =
        client.CopyObject(source_bucket_name, source_object_name,
                          destination_bucket_name, destination_object_name);
    if (!new_copy_meta) throw std::move(new_copy_meta).status();

    std::cout << "Successfully copied " << source_object_name << " in bucket "
              << source_bucket_name << " to bucket " << new_copy_meta->bucket()
              << " with name " << new_copy_meta->name()
              << ".\nThe full metadata after the copy is: " << *new_copy_meta
              << "\n";
  }

  namespace gcs = ::google::cloud::storage;
  using ::google::cloud::StatusOr;
  [](gcs::Client client, std::string const& source_bucket_name,
     std::string const& source_object_name,
     std::string const& destination_bucket_name,
     std::string const& destination_object_name,
     std::string const& key_base64) {
    StatusOr<gcs::ObjectMetadata> new_copy_meta = client.CopyObject(
        source_bucket_name, source_object_name, destination_bucket_name,
        destination_object_name, gcs::EncryptionKey::FromBase64Key(key_base64));
    if (!new_copy_meta) throw std::move(new_copy_meta).status();

    std::cout << "Successfully copied " << source_object_name << " in bucket "
              << source_bucket_name << " to bucket " << new_copy_meta->bucket()
              << " with name " << new_copy_meta->name()
              << ".\nThe full metadata after the copy is: " << *new_copy_meta
              << "\n";
  }

  namespace gcs = ::google::cloud::storage;
  using ::google::cloud::StatusOr;
  [](gcs::Client client, std::string const& bucket_name,
     std::string const& object_name) {
    StatusOr<gcs::ObjectMetadata> object_metadata =
        client.GetObjectMetadata(bucket_name, object_name);
    if (!object_metadata) throw std::move(object_metadata).status();

    std::cout << "The metadata for object " << object_metadata->name()
              << " in bucket " << object_metadata->bucket() << " is "
              << *object_metadata << "\n";
  }

  namespace gcs = ::google::cloud::storage;
  [](gcs::Client client, std::string const& bucket_name) {
    for (auto&& object_metadata : client.ListObjects(bucket_name)) {
      if (!object_metadata) throw std::move(object_metadata).status();

      std::cout << "bucket_name=" << object_metadata->bucket()
                << ", object_name=" << object_metadata->name() << "\n";
    }
  }

  namespace gcs = ::google::cloud::storage;
  [](gcs::Client client, std::string const& bucket_name,
     std::string const& bucket_prefix) {
    for (auto&& item : client.ListObjectsAndPrefixes(
             bucket_name, gcs::Prefix(bucket_prefix), gcs::Delimiter("/"))) {
      if (!item) throw std::move(item).status();
      auto result = *std::move(item);
      if (absl::holds_alternative<gcs::ObjectMetadata>(result)) {
        std::cout << "object_name="
                  << absl::get<gcs::ObjectMetadata>(result).name() << "\n";
      } else if (absl::holds_alternative<std::string>(result)) {
        std::cout << "prefix     =" << absl::get<std::string>(result) << "\n";
      }
    }
  }

  namespace gcs = ::google::cloud::storage;
  [](gcs::Client client, std::string const& bucket_name,
     std::string const& bucket_prefix) {
    for (auto&& item : client.ListObjectsAndPrefixes(
             bucket_name, gcs::Prefix(bucket_prefix), gcs::Delimiter("/"),
             gcs::IncludeFoldersAsPrefixes(true))) {
      if (!item) throw std::move(item).status();
      auto result = *std::move(item);
      if (absl::holds_alternative<gcs::ObjectMetadata>(result)) {
        std::cout << "object_name="
                  << absl::get<gcs::ObjectMetadata>(result).name() << "\n";
      } else if (absl::holds_alternative<std::string>(result)) {
        std::cout << "prefix     =" << absl::get<std::string>(result) << "\n";
      }
    }
  }

  // [START storage_stream_file_download]
  namespace gcs = ::google::cloud::storage;
  [](gcs::Client client, std::string const& bucket_name,
     std::string const& object_name) {
    gcs::ObjectReadStream stream = client.ReadObject(bucket_name, object_name);

    int count = 0;
    std::string line;
    while (std::getline(stream, line, '\n')) {
      ++count;
    }
    if (stream.bad()) throw google::cloud::Status(stream.status());

    std::cout << "The object has " << count << " lines\n";
  }
  // [END storage_stream_file_download]

  namespace gcs = ::google::cloud::storage;
  [](gcs::Client client, std::string const& bucket_name,
     std::string const& object_name, std::int64_t start, std::int64_t end) {
    gcs::ObjectReadStream stream =
        client.ReadObject(bucket_name, object_name, gcs::ReadRange(start, end));

    int count = 0;
    std::string line;
    while (std::getline(stream, line, '\n')) {
      std::cout << line << "\n";
      ++count;
    }
    if (stream.bad()) throw google::cloud::Status(stream.status());

    std::cout << "The requested range has " << count << " lines\n";
  }

  namespace gcs = ::google::cloud::storage;
  [](gcs::Client client, std::string const& bucket_name,
     std::string const& object_name, std::string const& base64_aes256_key) {
    gcs::ObjectReadStream stream =
        client.ReadObject(bucket_name, object_name,
                          gcs::EncryptionKey::FromBase64Key(base64_aes256_key));

    std::string data(std::istreambuf_iterator<char>{stream}, {});
    if (stream.bad()) throw google::cloud::Status(stream.status());
    std::cout << "The object contents are: " << data << "\n";
  }

  namespace gcs = ::google::cloud::storage;
  [](gcs::Client client, std::string const& bucket_name,
     std::string const& object_name) {
    auto is =
        client.ReadObject(bucket_name, object_name, gcs::AcceptEncodingGzip());
    auto const contents = std::string{std::istream_iterator<char>(is), {}};
    if (is.bad()) throw google::cloud::Status(is.status());
    std::cout << "The object has " << contents.size() << " characters\n";
  }

  namespace gcs = ::google::cloud::storage;
  using ::google::cloud::StatusOr;
  [](gcs::Client client, std::string const& bucket_name,
     std::string const& object_name, int desired_line_count) {
    std::string const text = "Lorem ipsum dolor sit amet";
    gcs::ObjectWriteStream stream =
        client.WriteObject(bucket_name, object_name);

    for (int lineno = 0; lineno != desired_line_count; ++lineno) {
      // Add 1 to the counter, because it is conventional to number lines
      // starting at 1.
      stream << (lineno + 1) << ": " << text << "\n";
    }

    stream.Close();

    StatusOr<gcs::ObjectMetadata> metadata = std::move(stream).metadata();
    if (!metadata) throw std::move(metadata).status();
    std::cout << "Successfully wrote to object " << metadata->name()
              << " its size is: " << metadata->size()
              << "\nFull metadata: " << *metadata << "\n";
  }

  namespace gcs = ::google::cloud::storage;
  using ::google::cloud::StatusOr;
  [](gcs::Client client, std::string const& bucket_name,
     std::string const& object_name, std::string const& kms_key_name) {
    gcs::ObjectWriteStream stream = client.WriteObject(
        bucket_name, object_name, gcs::KmsKeyName(kms_key_name));

    // Line numbers start at 1.
    for (int lineno = 1; lineno <= 10; ++lineno) {
      stream << lineno << ": placeholder text for CMEK example.\n";
    }

    stream.Close();

    StatusOr<gcs::ObjectMetadata> metadata = std::move(stream).metadata();
    if (!metadata) throw std::move(metadata).status();

    std::cout << "Successfully wrote to object " << metadata->name()
              << " its size is: " << metadata->size()
              << "\nFull metadata: " << *metadata << "\n";
  }

  namespace gcs = ::google::cloud::storage;
  return [](gcs::Client client, std::string const& bucket_name,
            std::string const& object_name) {
    gcs::ObjectWriteStream stream = client.WriteObject(
        bucket_name, object_name, gcs::NewResumableUploadSession(),
        gcs::AutoFinalizeDisabled());
    auto session_id = stream.resumable_session_id();
    std::cout << "Created resumable upload: " << session_id << "\n";
    // Because this stream was created with `AutoFinalizeDisabled()` its
    // destructor will *not* finalize the upload, allowing a separate process or
    // function to resume and continue the upload.
    stream << "This data will not get uploaded, it is too small\n";
    return session_id;
  }

  namespace gcs = ::google::cloud::storage;
  using ::google::cloud::StatusOr;
  [](gcs::Client client, std::string const& bucket_name,
     std::string const& object_name, std::string const& session_id) {
    // Restore a resumable upload stream, the library automatically queries the
    // state of the upload and discovers the next expected byte.
    gcs::ObjectWriteStream stream =
        client.WriteObject(bucket_name, object_name,
                           gcs::RestoreResumableUploadSession(session_id));
    if (!stream.IsOpen() && stream.metadata().ok()) {
      std::cout << "The upload has already been finalized.  The object "
                << "metadata is: " << *stream.metadata() << "\n";
    }
    if (stream.next_expected_byte() == 0) {
      // In this example we create a small object, smaller than the resumable
      // upload quantum (256 KiB), so either all the data is there or not.
      // Applications use `next_expected_byte()` to find the position in their
      // input where they need to start uploading.
      stream << R"""(
Lorem ipsum dolor sit amet, consectetur adipiscing
elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim
ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea
commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit
esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat
non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.
)""";
    }

    stream.Close();

    StatusOr<gcs::ObjectMetadata> metadata = stream.metadata();
    if (!metadata) throw std::move(metadata).status();
    std::cout << "Upload completed, the new object metadata is: " << *metadata
              << "\n";
  }

  namespace gcs = ::google::cloud::storage;
  using ::google::cloud::StatusOr;
  [](gcs::Client client, std::string const& file_name,
     std::string const& bucket_name, std::string const& object_name) {
    // Note that the client library automatically computes a hash on the
    // client-side to verify data integrity during transmission.
    StatusOr<gcs::ObjectMetadata> metadata = client.UploadFile(
        file_name, bucket_name, object_name, gcs::IfGenerationMatch(0));
    if (!metadata) throw std::move(metadata).status();

    std::cout << "Uploaded " << file_name << " to object " << metadata->name()
              << " in bucket " << metadata->bucket()
              << "\nFull metadata: " << *metadata << "\n";
  }

  namespace gcs = ::google::cloud::storage;
  using ::google::cloud::StatusOr;
  [](gcs::Client client, std::string const& file_name,
     std::string const& bucket_name, std::string const& object_name) {
    // Note that the client library automatically computes a hash on the
    // client-side to verify data integrity during transmission.
    StatusOr<gcs::ObjectMetadata> metadata = client.UploadFile(
        file_name, bucket_name, object_name, gcs::IfGenerationMatch(0),
        gcs::NewResumableUploadSession());
    if (!metadata) throw std::move(metadata).status();

    std::cout << "Uploaded " << file_name << " to object " << metadata->name()
              << " in bucket " << metadata->bucket()
              << "\nFull metadata: " << *metadata << "\n";
  }

  namespace gcs = ::google::cloud::storage;
  [](gcs::Client client, std::string const& bucket_name,
     std::string const& object_name, std::string const& file_name) {
    google::cloud::Status status =
        client.DownloadToFile(bucket_name, object_name, file_name);
    if (!status.ok()) throw std::runtime_error(status.message());

    std::cout << "Downloaded " << object_name << " to " << file_name << "\n";
  }

  namespace gcs = ::google::cloud::storage;
  [](gcs::Client client, std::string const& bucket_name,
     std::string const& object_name) {
    google::cloud::Status status =
        client.DeleteObject(bucket_name, object_name);

    if (!status.ok()) throw std::runtime_error(status.message());
    std::cout << "Deleted " << object_name << " in bucket " << bucket_name
              << "\n";
  }

  namespace gcs = ::google::cloud::storage;
  using ::google::cloud::StatusOr;
  [](gcs::Client client, std::string const& bucket_name,
     std::string const& object_name, std::string const& key,
     std::string const& value) {
    StatusOr<gcs::ObjectMetadata> object_metadata =
        client.GetObjectMetadata(bucket_name, object_name);
    if (!object_metadata) throw std::move(object_metadata).status();

    gcs::ObjectMetadata desired = *object_metadata;
    desired.mutable_metadata().emplace(key, value);

    StatusOr<gcs::ObjectMetadata> updated =
        client.UpdateObject(bucket_name, object_name, desired,
                            gcs::Generation(object_metadata->generation()));

    if (!updated) throw std::move(updated).status();
    std::cout << "Object updated. The full metadata after the update is: "
              << *updated << "\n";
  }

  namespace gcs = ::google::cloud::storage;
  using ::google::cloud::StatusOr;
  [](gcs::Client client, std::string const& bucket_name,
     std::string const& object_name, std::string const& key) {
    StatusOr<gcs::ObjectMetadata> original =
        client.GetObjectMetadata(bucket_name, object_name);

    if (!original) throw std::move(original).status();
    gcs::ObjectMetadata desired = *original;
    desired.mutable_metadata().erase(key);

    StatusOr<gcs::ObjectMetadata> updated =
        client.PatchObject(bucket_name, object_name, *original, desired);

    if (!updated) throw std::move(updated).status();
    std::cout << "Object updated. The full metadata after the update is: "
              << *updated << "\n";
  }

  namespace gcs = ::google::cloud::storage;
  using ::google::cloud::StatusOr;
  [](gcs::Client client, std::string const& bucket_name,
     std::string const& object_name, std::string const& content_type) {
    StatusOr<gcs::ObjectMetadata> updated = client.PatchObject(
        bucket_name, object_name,
        gcs::ObjectMetadataPatchBuilder().SetContentType(content_type));

    if (!updated) throw std::move(updated).status();
    std::cout << "Object updated. The full metadata after the update is: "
              << *updated << "\n";
  }

  namespace gcs = ::google::cloud::storage;
  using ::google::cloud::StatusOr;
  [](gcs::Client client, std::string const& bucket_name,
     std::string const& destination_object_name,
     std::vector<gcs::ComposeSourceObject> const& compose_objects) {
    StatusOr<gcs::ObjectMetadata> composed_object = client.ComposeObject(
        bucket_name, compose_objects, destination_object_name);
    if (!composed_object) throw std::move(composed_object).status();

    std::cout << "Composed new object " << composed_object->name()
              << " in bucket " << composed_object->bucket()
              << "\nFull metadata: " << *composed_object << "\n";
  }

  namespace gcs = ::google::cloud::storage;
  using ::google::cloud::StatusOr;
  [](gcs::Client client, std::string const& bucket_name,
     std::string const& destination_object_name,
     std::string const& base64_aes256_key,
     std::vector<gcs::ComposeSourceObject> const& compose_objects) {
    StatusOr<gcs::ObjectMetadata> composed_object = client.ComposeObject(
        bucket_name, compose_objects, destination_object_name,
        gcs::EncryptionKey::FromBase64Key(base64_aes256_key));
    if (!composed_object) throw std::move(composed_object).status();

    std::cout << "Composed new object " << composed_object->name()
              << " in bucket " << composed_object->bucket()
              << "\nFull metadata: " << *composed_object << "\n";
  }

  namespace gcs = ::google::cloud::storage;
  using ::google::cloud::StatusOr;
  [](gcs::Client client, std::string const& source_bucket_name,
     std::string const& source_object_name,
     std::string const& destination_bucket_name,
     std::string const& destination_object_name) {
    gcs::ObjectRewriter rewriter =
        client.RewriteObject(source_bucket_name, source_object_name,
                             destination_bucket_name, destination_object_name);

    auto callback = [](StatusOr<gcs::RewriteProgress> progress) {
      if (!progress) throw std::move(progress).status();
      std::cout << "Rewrote " << progress->total_bytes_rewritten << "/"
                << progress->object_size << "\n";
    };
    StatusOr<gcs::ObjectMetadata> metadata =
        rewriter.ResultWithProgressCallback(std::move(callback));
    if (!metadata) throw std::move(metadata).status();

    std::cout << "Rewrote object " << metadata->name() << " in bucket "
              << metadata->bucket() << "\nFull Metadata: " << *metadata << "\n";
  }

  namespace gcs = ::google::cloud::storage;
  using ::google::cloud::StatusOr;
  [](gcs::Client client, std::string const& source_bucket_name,
     std::string const& source_object_name,
     std::string const& destination_bucket_name,
     std::string const& destination_object_name,
     std::string const& rewrite_token) {
    gcs::ObjectRewriter rewriter = client.ResumeRewriteObject(
        source_bucket_name, source_object_name, destination_bucket_name,
        destination_object_name, rewrite_token,
        gcs::MaxBytesRewrittenPerCall(1024 * 1024));

    auto callback = [](StatusOr<gcs::RewriteProgress> progress) {
      if (!progress) throw std::move(progress).status();
      std::cout << "Rewrote " << progress->total_bytes_rewritten << "/"
                << progress->object_size << "\n";
    };
    StatusOr<gcs::ObjectMetadata> metadata =
        rewriter.ResultWithProgressCallback(std::move(callback));
    if (!metadata) throw std::move(metadata).status();

    std::cout << "Rewrote object " << metadata->name() << " in bucket "
              << metadata->bucket() << "\nFull Metadata: " << *metadata << "\n";
  }

  namespace gcs = ::google::cloud::storage;
  using ::google::cloud::StatusOr;
  [](gcs::Client client, std::string const& source_bucket_name,
     std::string const& source_object_name,
     std::string const& destination_bucket_name,
     std::string const& destination_object_name,
     std::string const& rewrite_token) {
    gcs::ObjectRewriter rewriter = client.ResumeRewriteObject(
        source_bucket_name, source_object_name, destination_bucket_name,
        destination_object_name, rewrite_token,
        gcs::MaxBytesRewrittenPerCall(1024 * 1024));

    auto callback = [](StatusOr<gcs::RewriteProgress> progress) {
      if (!progress) throw std::move(progress).status();
      std::cout << "Rewrote " << progress->total_bytes_rewritten << "/"
                << progress->object_size << "\n";
    };
    StatusOr<gcs::ObjectMetadata> metadata =
        rewriter.ResultWithProgressCallback(std::move(callback));
    if (!metadata) throw std::move(metadata).status();

    std::cout << "Rewrote object " << metadata->name() << " in bucket "
              << metadata->bucket() << "\nFull Metadata: " << *metadata << "\n";
  }

  namespace gcs = ::google::cloud::storage;
  using ::google::cloud::StatusOr;
  [](gcs::Client client, std::string const& source_bucket_name,
     std::string const& source_object_name,
     std::string const& destination_bucket_name,
     std::string const& destination_object_name) {
    StatusOr<gcs::ObjectMetadata> metadata = client.RewriteObjectBlocking(
        source_bucket_name, source_object_name, destination_bucket_name,
        destination_object_name);
    if (!metadata) throw std::move(metadata).status();

    std::cout << "Rewrote object " << destination_object_name
              << " Metadata: " << *metadata << "\n";
  }

  namespace gcs = ::google::cloud::storage;
  using ::google::cloud::StatusOr;
  [](gcs::Client client, std::string const& bucket_name,
     std::string const& object_name, std::string const& old_key_base64,
     std::string const& new_key_base64) {
    StatusOr<gcs::ObjectMetadata> object_metadata =
        client.RewriteObjectBlocking(
            bucket_name, object_name, bucket_name, object_name,
            gcs::SourceEncryptionKey::FromBase64Key(old_key_base64),
            gcs::EncryptionKey::FromBase64Key(new_key_base64));
    if (!object_metadata) throw std::move(object_metadata).status();

    std::cout << "Rotated key on object " << object_metadata->name()
              << " in bucket " << object_metadata->bucket()
              << "\nFull Metadata: " << *object_metadata << "\n";
  }

  namespace gcs = ::google::cloud::storage;
  using ::google::cloud::StatusOr;
  [](gcs::Client client, std::string const& bucket_name,
     std::string const& old_object_name, std::string const& new_object_name) {
    StatusOr<gcs::ObjectMetadata> metadata = client.RewriteObjectBlocking(
        bucket_name, old_object_name, bucket_name, new_object_name);
    if (!metadata) throw std::move(metadata).status();

    google::cloud::Status status =
        client.DeleteObject(bucket_name, old_object_name);
    if (!status.ok()) throw std::runtime_error(status.message());

    std::cout << "Renamed " << old_object_name << " to " << new_object_name
              << " in bucket " << bucket_name << "\n";
  }

  namespace gcs = ::google::cloud::storage;
  using ::google::cloud::StatusOr;
  [](gcs::Client client, std::string const& bucket_name) {
    StatusOr<std::vector<gcs::BucketAccessControl>> items =
        client.ListBucketAcl(bucket_name);

    if (!items) throw std::move(items).status();
    std::cout << "ACLs for bucket=" << bucket_name << "\n";
    for (gcs::BucketAccessControl const& acl : *items) {
      std::cout << acl.role() << ":" << acl.entity() << "\n";
    }
  }

  namespace gcs = ::google::cloud::storage;
  using ::google::cloud::StatusOr;
  [](gcs::Client client, std::string const& bucket_name,
     std::string const& entity, std::string const& role) {
    StatusOr<gcs::BucketAccessControl> bucket_acl =
        client.CreateBucketAcl(bucket_name, entity, role);

    if (!bucket_acl) throw std::move(bucket_acl).status();
    std::cout << "Role " << bucket_acl->role() << " granted to "
              << bucket_acl->entity() << " on bucket " << bucket_acl->bucket()
              << "\n"
              << "Full attributes: " << *bucket_acl << "\n";
  }

  namespace gcs = ::google::cloud::storage;
  [](gcs::Client client, std::string const& bucket_name,
     std::string const& entity) {
    google::cloud::Status status = client.DeleteBucketAcl(bucket_name, entity);

    if (!status.ok()) throw std::runtime_error(status.message());
    std::cout << "Deleted ACL entry for " << entity << " in bucket "
              << bucket_name << "\n";
  }

  namespace gcs = ::google::cloud::storage;
  using ::google::cloud::StatusOr;
  [](gcs::Client client, std::string const& bucket_name,
     std::string const& entity) {
    StatusOr<gcs::BucketAccessControl> acl =
        client.GetBucketAcl(bucket_name, entity);

    if (!acl) throw std::move(acl).status();
    std::cout << "ACL entry for " << acl->entity() << " in bucket "
              << acl->bucket() << " is " << *acl << "\n";
  }

  namespace gcs = ::google::cloud::storage;
  using ::google::cloud::StatusOr;
  [](gcs::Client client, std::string const& bucket_name,
     std::string const& entity, std::string const& role) {
    gcs::BucketAccessControl desired_acl =
        gcs::BucketAccessControl().set_entity(entity).set_role(role);

    StatusOr<gcs::BucketAccessControl> updated_acl =
        client.UpdateBucketAcl(bucket_name, desired_acl);

    if (!updated_acl) throw std::move(updated_acl).status();
    std::cout << "Bucket ACL updated. The ACL entry for "
              << updated_acl->entity() << " in bucket " << updated_acl->bucket()
              << " is " << *updated_acl << "\n";
  }

  namespace gcs = ::google::cloud::storage;
  using ::google::cloud::StatusOr;
  [](gcs::Client client, std::string const& bucket_name,
     std::string const& entity, std::string const& role) {
    StatusOr<gcs::BucketAccessControl> original_acl =
        client.GetBucketAcl(bucket_name, entity);
    if (!original_acl) throw std::move(original_acl).status();

    auto new_acl = *original_acl;
    new_acl.set_role(role);

    StatusOr<gcs::BucketAccessControl> patched_acl =
        client.PatchBucketAcl(bucket_name, entity, *original_acl, new_acl);

    if (!patched_acl) throw std::move(patched_acl).status();
    std::cout << "ACL entry for " << patched_acl->entity() << " in bucket "
              << patched_acl->bucket() << " is now " << *patched_acl << "\n";
  }

  namespace gcs = ::google::cloud::storage;
  using ::google::cloud::StatusOr;
  [](gcs::Client client, std::string const& bucket_name,
     std::string const& entity, std::string const& role) {
    StatusOr<gcs::BucketAccessControl> patched_acl = client.PatchBucketAcl(
        bucket_name, entity,
        gcs::BucketAccessControlPatchBuilder().set_role(role));

    if (!patched_acl) throw std::move(patched_acl).status();
    std::cout << "ACL entry for " << patched_acl->entity() << " in bucket "
              << patched_acl->bucket() << " is now " << *patched_acl << "\n";
  }

  namespace gcs = ::google::cloud::storage;
  using ::google::cloud::StatusOr;
  [](gcs::Client client, std::string const& bucket_name,
     std::string const& object_name) {
    StatusOr<std::vector<gcs::ObjectAccessControl>> items =
        client.ListObjectAcl(bucket_name, object_name);

    if (!items) throw std::move(items).status();
    std::cout << "ACLs for object=" << object_name << " in bucket "
              << bucket_name << "\n";
    for (gcs::ObjectAccessControl const& acl : *items) {
      std::cout << acl.role() << ":" << acl.entity() << "\n";
    }
  }

  namespace gcs = ::google::cloud::storage;
  using ::google::cloud::StatusOr;
  [](gcs::Client client, std::string const& bucket_name,
     std::string const& object_name, std::string const& entity,
     std::string const& role) {
    StatusOr<gcs::ObjectAccessControl> object_acl =
        client.CreateObjectAcl(bucket_name, object_name, entity, role);

    if (!object_acl) throw std::move(object_acl).status();
    std::cout << "Role " << object_acl->role() << " granted to "
              << object_acl->entity() << " on " << object_acl->object()
              << "\nFull attributes: " << *object_acl << "\n";
  }

  namespace gcs = ::google::cloud::storage;
  [](gcs::Client client, std::string const& bucket_name,
     std::string const& object_name, std::string const& entity) {
    google::cloud::Status status =
        client.DeleteObjectAcl(bucket_name, object_name, entity);

    if (!status.ok()) throw std::runtime_error(status.message());
    std::cout << "Deleted ACL entry for " << entity << " in object "
              << object_name << " in bucket " << bucket_name << "\n";
  }

  namespace gcs = ::google::cloud::storage;
  using ::google::cloud::StatusOr;
  [](gcs::Client client, std::string const& bucket_name,
     std::string const& object_name, std::string const& entity) {
    StatusOr<gcs::ObjectAccessControl> acl =
        client.GetObjectAcl(bucket_name, object_name, entity);

    if (!acl) throw std::move(acl).status();
    std::cout << "ACL entry for " << acl->entity() << " in object "
              << acl->object() << " in bucket " << acl->bucket() << " is "
              << *acl << "\n";
  }

  namespace gcs = ::google::cloud::storage;
  using ::google::cloud::StatusOr;
  [](gcs::Client client, std::string const& bucket_name,
     std::string const& object_name, std::string const& entity,
     std::string const& role) {
    StatusOr<gcs::ObjectAccessControl> current_acl =
        client.GetObjectAcl(bucket_name, object_name, entity);

    if (!current_acl) throw std::move(current_acl).status();
    current_acl->set_role(role);

    StatusOr<gcs::ObjectAccessControl> updated_acl =
        client.UpdateObjectAcl(bucket_name, object_name, *current_acl);

    if (!updated_acl) throw std::move(updated_acl).status();
    std::cout << "ACL entry for " << updated_acl->entity() << " in object "
              << updated_acl->object() << " in bucket " << updated_acl->bucket()
              << " is now " << *updated_acl << "\n";
  }

  namespace gcs = ::google::cloud::storage;
  using ::google::cloud::StatusOr;
  [](gcs::Client client, std::string const& bucket_name,
     std::string const& object_name, std::string const& entity,
     std::string const& role) {
    StatusOr<gcs::ObjectAccessControl> original_acl =
        client.GetObjectAcl(bucket_name, object_name, entity);
    if (!original_acl) throw std::move(original_acl).status();

    gcs::ObjectAccessControl new_acl = *original_acl;
    new_acl.set_role(role);

    StatusOr<gcs::ObjectAccessControl> patched_acl = client.PatchObjectAcl(
        bucket_name, object_name, entity, *original_acl, new_acl);

    if (!patched_acl) throw std::move(patched_acl).status();
    std::cout << "ACL entry for " << patched_acl->entity() << " in object "
              << patched_acl->object() << " in bucket " << patched_acl->bucket()
              << " is now " << *patched_acl << "\n";
  }

  namespace gcs = ::google::cloud::storage;
  using ::google::cloud::StatusOr;
  [](gcs::Client client, std::string const& bucket_name,
     std::string const& object_name, std::string const& entity,
     std::string const& role) {
    StatusOr<gcs::ObjectAccessControl> patched_acl = client.PatchObjectAcl(
        bucket_name, object_name, entity,
        gcs::ObjectAccessControlPatchBuilder().set_role(role));

    if (!patched_acl) throw std::move(patched_acl).status();
    std::cout << "ACL entry for " << patched_acl->entity() << " in object "
              << patched_acl->object() << " in bucket " << patched_acl->bucket()
              << " is now " << *patched_acl << "\n";
  }

  namespace gcs = ::google::cloud::storage;
  using ::google::cloud::StatusOr;
  [](gcs::Client client, std::string const& bucket_name) {
    StatusOr<std::vector<gcs::ObjectAccessControl>> items =
        client.ListDefaultObjectAcl(bucket_name);

    if (!items) throw std::move(items).status();
    std::cout << "ACLs for bucket=" << bucket_name << "\n";
    for (gcs::ObjectAccessControl const& acl : *items) {
      std::cout << acl.role() << ":" << acl.entity() << "\n";
    }
  }

  namespace gcs = ::google::cloud::storage;
  using ::google::cloud::StatusOr;
  [](gcs::Client client, std::string const& bucket_name,
     std::string const& entity, std::string const& role) {
    StatusOr<gcs::ObjectAccessControl> default_object_acl =
        client.CreateDefaultObjectAcl(bucket_name, entity, role);
    if (!default_object_acl) throw std::move(default_object_acl).status();

    std::cout << "Role " << default_object_acl->role()
              << " will be granted default to " << default_object_acl->entity()
              << " on any new object created on bucket "
              << default_object_acl->bucket() << "\n"
              << "Full attributes: " << *default_object_acl << "\n";
  }

  namespace gcs = ::google::cloud::storage;
  [](gcs::Client client, std::string const& bucket_name,
     std::string const& entity) {
    google::cloud::Status status =
        client.DeleteDefaultObjectAcl(bucket_name, entity);

    if (!status.ok()) throw std::runtime_error(status.message());
    std::cout << "Deleted ACL entry for " << entity << " in bucket "
              << bucket_name << "\n";
  }

  namespace gcs = ::google::cloud::storage;
  using ::google::cloud::StatusOr;
  [](gcs::Client client, std::string const& bucket_name,
     std::string const& entity) {
    StatusOr<gcs::ObjectAccessControl> acl =
        client.GetDefaultObjectAcl(bucket_name, entity);

    if (!acl) throw std::move(acl).status();
    std::cout << "Default Object ACL entry for " << acl->entity()
              << " in bucket " << acl->bucket() << " is " << *acl << "\n";
  }

  namespace gcs = ::google::cloud::storage;
  using ::google::cloud::StatusOr;
  [](gcs::Client client, std::string const& bucket_name,
     std::string const& entity, std::string const& role) {
    StatusOr<gcs::ObjectAccessControl> original_acl =
        client.GetDefaultObjectAcl(bucket_name, entity);
    if (!original_acl) throw std::move(original_acl).status();

    original_acl->set_role(role);

    StatusOr<gcs::ObjectAccessControl> updated_acl =
        client.UpdateDefaultObjectAcl(bucket_name, *original_acl);
    if (!updated_acl) throw std::move(updated_acl).status();

    std::cout << "Default Object ACL entry for " << updated_acl->entity()
              << " in bucket " << updated_acl->bucket() << " is now "
              << *updated_acl << "\n";
  }

  namespace gcs = ::google::cloud::storage;
  using ::google::cloud::StatusOr;
  [](gcs::Client client, std::string const& bucket_name,
     std::string const& entity, std::string const& role) {
    StatusOr<gcs::ObjectAccessControl> original_acl =
        client.GetDefaultObjectAcl(bucket_name, entity);
    if (!original_acl) throw std::move(original_acl).status();

    auto new_acl = *original_acl;
    new_acl.set_role(role);

    StatusOr<gcs::ObjectAccessControl> patched_acl =
        client.PatchDefaultObjectAcl(bucket_name, entity, *original_acl,
                                     new_acl);

    if (!patched_acl) throw std::move(patched_acl).status();
    std::cout << "Default Object ACL entry for " << patched_acl->entity()
              << " in bucket " << patched_acl->bucket() << " is now "
              << *patched_acl << "\n";
  }

  namespace gcs = ::google::cloud::storage;
  using ::google::cloud::StatusOr;
  [](gcs::Client client, std::string const& bucket_name,
     std::string const& entity, std::string const& role) {
    StatusOr<gcs::ObjectAccessControl> patched_acl =
        client.PatchDefaultObjectAcl(
            bucket_name, entity,
            gcs::ObjectAccessControlPatchBuilder().set_role(role));

    if (!patched_acl) throw std::move(patched_acl).status();
    std::cout << "Default Object ACL entry for " << patched_acl->entity()
              << " in bucket " << patched_acl->bucket() << " is now "
              << *patched_acl << "\n";
  }

  namespace gcs = ::google::cloud::storage;
  using ::google::cloud::StatusOr;
  [](gcs::Client client, std::string const& project_id) {
    StatusOr<gcs::ServiceAccount> account =
        client.GetServiceAccountForProject(project_id);
    if (!account) throw std::move(account).status();

    std::cout << "The service account details for project " << project_id
              << " are " << *account << "\n";
  }

  namespace gcs = ::google::cloud::storage;
  using ::google::cloud::StatusOr;
  [](gcs::Client client) {
    StatusOr<gcs::ServiceAccount> account = client.GetServiceAccount();
    if (!account) throw std::move(account).status();

    std::cout << "The service account details are " << *account << "\n";
  }

  namespace gcs = ::google::cloud::storage;
  using ::google::cloud::StatusOr;
  [](gcs::Client client) {
    int count = 0;
    gcs::ListHmacKeysReader hmac_keys_list = client.ListHmacKeys();
    for (auto& key : hmac_keys_list) {
      if (!key) throw std::move(key).status();

      std::cout << "service_account_email = " << key->service_account_email()
                << "\naccess_id = " << key->access_id() << "\n";
      ++count;
    }
    if (count == 0) {
      std::cout << "No HMAC keys in default project\n";
    }
  }

  namespace gcs = ::google::cloud::storage;
  using ::google::cloud::StatusOr;
  [](gcs::Client client, std::string const& service_account) {
    int count = 0;
    gcs::ListHmacKeysReader hmac_keys_list =
        client.ListHmacKeys(gcs::ServiceAccountFilter(service_account));
    for (auto& key : hmac_keys_list) {
      if (!key) throw std::move(key).status();

      std::cout << "service_account_email = " << key->service_account_email()
                << "\naccess_id = " << key->access_id() << "\n";
      ++count;
    }
    if (count == 0) {
      std::cout << "No HMAC keys for service account " << service_account
                << " in default project\n";
    }
  }

  namespace gcs = ::google::cloud::storage;
  using ::google::cloud::StatusOr;
  return [](gcs::Client client, std::string const& service_account_email) {
    StatusOr<std::pair<gcs::HmacKeyMetadata, std::string>> key_info =
        client.CreateHmacKey(service_account_email);
    if (!key_info) throw std::move(key_info).status();

    std::cout << "The base64 encoded secret is: " << key_info->second
              << "\nDo not miss that secret, there is no API to recover it."
              << "\nThe HMAC key metadata is: " << key_info->first << "\n";
    return key_info->first.access_id();
  }

  namespace gcs = ::google::cloud::storage;
  using ::google::cloud::StatusOr;
  return [](gcs::Client client, std::string const& project_id,
            std::string const& service_account_email) {
    StatusOr<std::pair<gcs::HmacKeyMetadata, std::string>> hmac_key_details =
        client.CreateHmacKey(service_account_email,
                             gcs::OverrideDefaultProject(project_id));
    if (!hmac_key_details) throw std::move(hmac_key_details).status();

    std::cout << "The base64 encoded secret is: " << hmac_key_details->second
              << "\nDo not miss that secret, there is no API to recover it."
              << "\nThe HMAC key metadata is: " << hmac_key_details->first
              << "\n";
    return hmac_key_details->first.access_id();
  }

  namespace gcs = ::google::cloud::storage;
  [](gcs::Client client, std::string const& access_id) {
    google::cloud::Status status = client.DeleteHmacKey(access_id);
    if (!status.ok()) throw std::runtime_error(status.message());

    std::cout << "The key is deleted, though it may still appear"
              << " in ListHmacKeys() results.\n";
  }

  namespace gcs = ::google::cloud::storage;
  using ::google::cloud::StatusOr;
  [](gcs::Client client, std::string const& access_id) {
    StatusOr<gcs::HmacKeyMetadata> hmac_key = client.GetHmacKey(access_id);
    if (!hmac_key) throw std::move(hmac_key).status();

    std::cout << "The HMAC key metadata is: " << *hmac_key << "\n";
  }

  namespace gcs = ::google::cloud::storage;
  using ::google::cloud::StatusOr;
  [](gcs::Client client, std::string const& access_id,
     std::string const& state) {
    StatusOr<gcs::HmacKeyMetadata> updated = client.UpdateHmacKey(
        access_id, gcs::HmacKeyMetadata().set_state(state));
    if (!updated) throw std::move(updated).status();

    std::cout << "The updated HMAC key metadata is: " << *updated << "\n";
  }

  namespace gcs = ::google::cloud::storage;
  using ::google::cloud::StatusOr;
  [](gcs::Client client, std::string const& bucket_name,
     std::string const& object_name, std::string const& signing_account) {
    StatusOr<std::string> signed_url = client.CreateV2SignedUrl(
        "GET", bucket_name, object_name,
        gcs::ExpirationTime(std::chrono::system_clock::now() +
                            std::chrono::minutes(15)),
        gcs::SigningAccount(signing_account));

    if (!signed_url) throw std::move(signed_url).status();
    std::cout << "The signed url is: " << *signed_url << "\n\n"
              << "You can use this URL with any user agent, for example:\n"
              << "curl '" << *signed_url << "'\n";
  }

  namespace gcs = ::google::cloud::storage;
  using ::google::cloud::StatusOr;
  [](gcs::Client client, std::string const& bucket_name,
     std::string const& object_name, std::string const& signing_account) {
    StatusOr<std::string> signed_url = client.CreateV2SignedUrl(
        "PUT", bucket_name, object_name,
        gcs::ExpirationTime(std::chrono::system_clock::now() +
                            std::chrono::minutes(15)),
        gcs::ContentType("application/octet-stream"),
        gcs::SigningAccount(signing_account));

    if (!signed_url) throw std::move(signed_url).status();
    std::cout << "The signed url is: " << *signed_url << "\n\n"
              << "You can use this URL with any user agent, for example:\n"
              << "curl -X PUT -H 'Content-Type: application/octet-stream'"
              << " --upload-file my-file '" << *signed_url << "'\n";
  }

  namespace gcs = ::google::cloud::storage;
  using ::google::cloud::StatusOr;
  [](gcs::Client client, std::string const& bucket_name,
     std::string const& object_name, std::string const& signing_account) {
    StatusOr<std::string> signed_url = client.CreateV4SignedUrl(
        "GET", bucket_name, object_name,
        gcs::SignedUrlDuration(std::chrono::minutes(15)),
        gcs::SigningAccount(signing_account));

    if (!signed_url) throw std::move(signed_url).status();
    std::cout << "The signed url is: " << *signed_url << "\n\n"
              << "You can use this URL with any user agent, for example:\n"
              << "curl '" << *signed_url << "'\n";
  }

  namespace gcs = ::google::cloud::storage;
  using ::google::cloud::StatusOr;
  [](gcs::Client client, std::string const& bucket_name,
     std::string const& object_name, std::string const& signing_account) {
    StatusOr<std::string> signed_url = client.CreateV4SignedUrl(
        "PUT", bucket_name, object_name,
        gcs::SignedUrlDuration(std::chrono::minutes(15)),
        gcs::AddExtensionHeader("content-type", "application/octet-stream"),
        gcs::SigningAccount(signing_account));

    if (!signed_url) throw std::move(signed_url).status();
    std::cout << "The signed url is: " << *signed_url << "\n\n"
              << "You can use this URL with any user agent, for example:\n"
              << "curl -X PUT -H 'Content-Type: application/octet-stream'"
              << " --upload-file my-file '" << *signed_url << "'\n";
  }

  namespace gcs = ::google::cloud::storage;
  using ::google::cloud::StatusOr;
  [](gcs::Client client, std::string const& bucket_name) {
    StatusOr<std::vector<gcs::NotificationMetadata>> items =
        client.ListNotifications(bucket_name);
    if (!items) throw std::move(items).status();

    std::cout << "Notifications for bucket=" << bucket_name << "\n";
    for (gcs::NotificationMetadata const& notification : *items) {
      std::cout << notification << "\n";
    }
  }

  namespace gcs = ::google::cloud::storage;
  using ::google::cloud::StatusOr;
  [](gcs::Client client, std::string const& bucket_name,
     std::string const& topic_name) {
    StatusOr<gcs::NotificationMetadata> notification =
        client.CreateNotification(bucket_name, topic_name,
                                  gcs::NotificationMetadata());
    if (!notification) throw std::move(notification).status();

    std::cout << "Successfully created notification " << notification->id()
              << " for bucket " << bucket_name << "\n";
    std::cout << "Full details for the notification:\n"
              << *notification << "\n";
  }

  namespace gcs = ::google::cloud::storage;
  using ::google::cloud::StatusOr;
  [](gcs::Client client, std::string const& bucket_name,
     std::string const& topic_name) {
    StatusOr<gcs::NotificationMetadata> notification =
        client.CreateNotification(bucket_name, topic_name,
                                  gcs::NotificationMetadata());
    if (!notification) throw std::move(notification).status();

    std::cout << "Successfully created notification " << notification->id()
              << " for bucket " << bucket_name << "\n";
    std::cout << "Full details for the notification:\n"
              << *notification << "\n";
  }

  namespace gcs = ::google::cloud::storage;
  using ::google::cloud::StatusOr;
  [](gcs::Client client, std::string const& bucket_name,
     std::string const& notification_id) {
    StatusOr<gcs::NotificationMetadata> notification =
        client.GetNotification(bucket_name, notification_id);
    if (!notification) throw std::move(notification).status();

    std::cout << "Notification " << notification->id() << " for bucket "
              << bucket_name << "\n";
    if (notification->object_name_prefix().empty()) {
      std::cout << "This notification is sent for all objects in the bucket\n";
    } else {
      std::cout << "This notification is sent only for objects starting with"
                << " the prefix " << notification->object_name_prefix() << "\n";
    }
    std::cout << "Full details for the notification:\n"
              << *notification << "\n";
  }

  namespace gcs = ::google::cloud::storage;
  [](gcs::Client client, std::string const& bucket_name,
     std::string const& notification_id) {
    google::cloud::Status status =
        client.DeleteNotification(bucket_name, notification_id);
    if (!status.ok()) throw std::runtime_error(status.message());

    std::cout << "Successfully deleted notification " << notification_id
              << " on bucket " << bucket_name << "\n";
  }

  namespace gcs = ::google::cloud::storage;
  using ::google::cloud::StatusOr;
  [](gcs::Client client, std::string const& bucket_name,
     std::string const& signing_account) {
    StatusOr<gcs::PolicyDocumentResult> document =
        client.CreateSignedPolicyDocument(
            gcs::PolicyDocument{
                std::chrono::system_clock::now() + std::chrono::minutes(15),
                {
                    gcs::PolicyDocumentCondition::StartsWith("key", ""),
                    gcs::PolicyDocumentCondition::ExactMatchObject(
                        "acl", "bucket-owner-read"),
                    gcs::PolicyDocumentCondition::ExactMatchObject("bucket",
                                                                   bucket_name),
                    gcs::PolicyDocumentCondition::ExactMatch("Content-Type",
                                                             "image/jpeg"),
                    gcs::PolicyDocumentCondition::ContentLengthRange(0,
                                                                     1000000),
                }},
            gcs::SigningAccount(signing_account));
    if (!document) throw std::move(document).status();

    std::cout << "The signed document is: " << *document << "\n\n"
              << "You can use this with an HTML form.\n";
  }

  namespace gcs = ::google::cloud::storage;
  using ::google::cloud::StatusOr;
  [](gcs::Client client, std::string const& bucket_name,
     std::string const& signing_account) {
    StatusOr<gcs::PolicyDocumentV4Result> document =
        client.GenerateSignedPostPolicyV4(
            gcs::PolicyDocumentV4{
                bucket_name,
                "scan_0001.jpg",
                std::chrono::minutes(15),
                std::chrono::system_clock::now(),
                {
                    gcs::PolicyDocumentCondition::StartsWith("key", ""),
                    gcs::PolicyDocumentCondition::ExactMatchObject(
                        "acl", "bucket-owner-read"),
                    gcs::PolicyDocumentCondition::ExactMatch("Content-Type",
                                                             "image/jpeg"),
                    gcs::PolicyDocumentCondition::ContentLengthRange(0,
                                                                     1000000),
                }},
            gcs::SigningAccount(signing_account));
    if (!document) throw std::move(document).status();

    std::cout << "The signed document is: " << *document << "\n\n"
              << "You can use this with an HTML form.\n";
  }