ENH: Support FIND and COUNT queries

Summary

See https://gitlab.indiscale.com/caosdb/customers/lfpb/management/-/issues/399. Introduces FIND and Count queries.

Focus

Most changes are in transaction.h and transaction.cpp.

Test Environment

Unit and integration tests with server in f-grpc-f-query

Check List for the Author

Please, prepare your MR for a review. Be sure to write a summary and a focus and create gitlab comments for the reviewer. They should guide the reviewer through the changes, explain your changes and also point out open questions. For further good practices have a look at our review guidelines

• All automated tests pass
• Reference related Issues
• [ ] Up-to-date CHANGELOG.md
• Annotations in code (Gitlab comments)
  • Intent of new code
  • Problems with old code
  • Why this implementation?

Check List for the Reviewer

• I understand the intent of this MR
• All automated tests pass
• [ ] Up-to-date CHANGELOG.md
• The test environment setup works and the intended behavior is reproducible in the test environment
• In-code documentation and comments are up-to-date.
• Check: Are there specifications? Are they satisfied?

For further good practices have a look at our review guidelines.

src/caosdb/transaction.cpp

@@ -96,6 +96,8 @@ using caosdb::entity::v1alpha1::MultiTransactionRequest;
 using caosdb::entity::v1alpha1::MultiTransactionResponse;
 using WrappedResponseCase =
   caosdb::entity::v1alpha1::TransactionResponse::WrappedResponseCase;
+using QueryResponseCase =
+  caosdb::entity::v1alpha1::RetrieveResponse::QueryResponseCase;
 using caosdb::utility::get_arena;
 using grpc::ClientAsyncResponseReader;
 using ProtoEntity = caosdb::entity::v1alpha1::Entity;
@@ -131,28 +133,8 @@ auto ResultSet::end() const -> ResultSet::iterator {
   return ResultSet::iterator(this, Size());
 }
 
-MultiResultSet::MultiResultSet(MultiTransactionResponse *response) {
-  auto *responses = response->mutable_responses();
-  for (auto sub_response : *responses) {
-    switch (sub_response.wrapped_response_case()) {
-    case WrappedResponseCase::kRetrieveResponse:
-      this->entities.push_back(std::make_unique<Entity>(
-        sub_response.mutable_retrieve_response()->release_entity()));
-      break;
-    case WrappedResponseCase::kInsertResponse:
-      this->entities.push_back(
-        std::make_unique<Entity>(sub_response.release_insert_response()));
-      break;
-    case WrappedResponseCase::kDeleteResponse:
-      this->entities.push_back(
-        std::make_unique<Entity>(sub_response.release_insert_response()));
-      break;
-    default:
-      // TODO(tf) Updates
-      break;
-    }
-  }
-}
+MultiResultSet::MultiResultSet(std::vector<std::unique_ptr<Entity>> result_set)
+  : entities(std::move(result_set)) {}
 
 [[nodiscard]] auto UniqueResult::GetEntity() const -> const Entity & {
   const Entity *result = this->entity.get();
@@ -166,6 +148,7 @@ Transaction::Transaction(
     response(google::protobuf::Arena::CreateMessage<MultiTransactionResponse>(
       get_arena())) {
   this->service_stub = std::move(service_stub);
+  this->query_count = -1;
 }
 
 auto Transaction::RetrieveById(const std::string &id) noexcept -> StatusCode {
@@ -197,7 +180,7 @@ auto Transaction::DeleteById(const std::string &id) noexcept -> StatusCode {
   auto *sub_request = this->request->add_requests();
   sub_request->mutable_delete_request()->set_id(id);
 
-  this->status = TransactionStatus::READY();
+  this->status = TransactionStatus::GO_ON();
   return this->status.GetCode();
 }
 
@@ -300,12 +283,29 @@ auto Transaction::WaitForIt() const noexcept -> TransactionStatus {
     auto *responses = this->response->mutable_responses(0);
     switch (responses->wrapped_response_case()) {
     case WrappedResponseCase::kRetrieveResponse: {
-      auto *entity = responses->mutable_retrieve_response()->release_entity();
-      if (!entity->errors().empty()) {
-        this->status = TransactionStatus::TRANSACTION_ERROR(
-          "The request returned with errors.");
+      auto *retrieve_response = responses->mutable_retrieve_response();
+      switch (retrieve_response->query_response_case()) {
+      case QueryResponseCase::kEntity: {
+        auto *entity = retrieve_response->release_entity();
+        if (!entity->errors().empty()) {
+          this->status = TransactionStatus::TRANSACTION_ERROR(
+            "The request returned with errors.");
+        }
+        this->result_set = std::make_unique<UniqueResult>(entity);
+      } break;
+      case QueryResponseCase::kSelectResult: {
+        // TODO(tf) Select queries
+      } break;
+      case QueryResponseCase::kCountResult: {
+        this->query_count = retrieve_response->count_result();
+        std::vector<std::unique_ptr<Entity>> entities;
+        this->result_set =
+          std::make_unique<MultiResultSet>(std::move(entities));
+      } break;
+      default:
+        // TODO(tf) Error
+        break;
       }
-      this->result_set = std::make_unique<UniqueResult>(entity);
     } break;
     case WrappedResponseCase::kUpdateResponse: {
       auto *updatedIdResponse = responses->mutable_update_response();
@@ -336,7 +336,28 @@ auto Transaction::WaitForIt() const noexcept -> TransactionStatus {
       break;
     }
   } else {
-    this->result_set = std::make_unique<MultiResultSet>(this->response);
+    auto *responses = this->response->mutable_responses();
+    std::vector<std::unique_ptr<Entity>> entities;
+    for (auto sub_response : *responses) {
+      switch (sub_response.wrapped_response_case()) {
+      case WrappedResponseCase::kRetrieveResponse:
+        entities.push_back(std::make_unique<Entity>(
+          sub_response.mutable_retrieve_response()->release_entity()));
+        break;
+      case WrappedResponseCase::kInsertResponse:
+        entities.push_back(
+          std::make_unique<Entity>(sub_response.release_insert_response()));
+        break;
+      case WrappedResponseCase::kDeleteResponse:
+        entities.push_back(
+          std::make_unique<Entity>(sub_response.release_insert_response()));
+        break;
+      default:
+        // TODO(tf) Updates
+        break;
+      }
+    }
+    this->result_set = std::make_unique<MultiResultSet>(std::move(entities));
   }
 
   return this->status;