text: ////////////////////////////////////////////////////////////////////////////////
  /// DISCLAIMER
  ///
  /// Copyright 2014-2021 ArangoDB GmbH, Cologne, Germany
  /// Copyright 2004-2014 triAGENS GmbH, Cologne, Germany
  ///
  /// 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.
  ///
  /// Copyright holder is ArangoDB GmbH, Cologne, Germany
  ///
  /// @author Simon Grätzer
  ////////////////////////////////////////////////////////////////////////////////
  
  #pragma once
  
  #include <memory>
  #include <mutex>
  #include <string>
  #include <thread>
  
  #include "Basics/Result.h"
  #include "RestHandler/RestVocbaseBaseHandler.h"
  
  #include <velocypack/Builder.h>
  
  namespace arangodb {
  class LogicalCollection;
  
  class RestIndexHandler : public arangodb::RestVocbaseBaseHandler {
   public:
    RestIndexHandler(application_features::ApplicationServer&, GeneralRequest*,
                     GeneralResponse*);
  
    ~RestIndexHandler();
  
   public:
    char const* name() const override final { return "RestIndexHandler"; }
    RequestLane lane() const override final { return RequestLane::CLIENT_SLOW; }
    RestStatus execute() override;
    RestStatus continueExecute() override;
    void shutdownExecute(bool isFinalized) noexcept override;
  
   private:
    RestStatus getIndexes();
    RestStatus getSelectivityEstimates();
    RestStatus createIndex();
    RestStatus dropIndex();
  
    void shutdownBackgroundThread();
  
    std::shared_ptr<LogicalCollection> collection(std::string const& cName);
  
    struct CreateInBackgroundData {
      std::unique_ptr<std::thread> thread;
      Result result;
      arangodb::velocypack::Builder response;
    };
  
    std::mutex _mutex;
    CreateInBackgroundData _createInBackgroundData;
  };
  }  // namespace arangodb
  