Adding C++ KmsClients and KmsAeadKeyManager

PiperOrigin-RevId: 242661064
GitOrigin-RevId: f9367173bea3b5832068a9eebfc19e85244ae98e

1 files changed, 69 insertions, 0 deletions

diff --git a/cc/kms_clients.h b/cc/kms_clients.h
new file mode 100644
index 000000000..c28012acd
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+++ b/cc/kms_clients.h
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+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+///////////////////////////////////////////////////////////////////////////////
+
+#ifndef TINK_KMS_CLIENTS_H_
+#define TINK_KMS_CLIENTS_H_
+
+#include <vector>
+
+#include "absl/base/thread_annotations.h"
+#include "absl/strings/string_view.h"
+#include "absl/synchronization/mutex.h"
+#include "tink/kms_client.h"
+#include "tink/util/status.h"
+#include "tink/util/statusor.h"
+
+namespace crypto {
+namespace tink {
+
+// A container for KmsClient-objects that are needed by KeyManager-objects for
+// primitives that use KMS-managed keys.
+//
+// This class consists exclusively of static methods that register and load
+// KmsClient-objects.
+class KmsClients {
+ public:
+  // Adds 'kms_client', which must be non-null, to the list
+  // of the list of known clients.
+  static crypto::tink::util::Status Add(std::unique_ptr<KmsClient> kms_client) {
+    return GlobalInstance().LocalAdd(std::move(kms_client));
+  }
+
+  // Returns the first KmsClient that was added previously via Add(),
+  // and that does support 'key_uri', which must be non-empty.
+  // Retains the ownership of the returned KmsClient.
+  static crypto::tink::util::StatusOr<const KmsClient*>
+      Get(absl::string_view key_uri) {
+    return GlobalInstance().LocalGet(key_uri);
+  }
+
+ private:
+  KmsClients() {}
+
+  // Per-instance API, to be used by GlobalInstance();
+  crypto::tink::util::Status
+      LocalAdd(std::unique_ptr<KmsClient> kms_client);
+  crypto::tink::util::StatusOr<const KmsClient*>
+      LocalGet(absl::string_view key_uri);
+  absl::Mutex clients_mutex_;
+  std::vector<std::unique_ptr<KmsClient>> clients_
+      GUARDED_BY(clients_mutex_);
+
+  static KmsClients& GlobalInstance();
+};
+
+}  // namespace tink
+}  // namespace crypto
+
+#endif  // TINK_KMS_CLIENTS_H_