entities_manager.h

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/*
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  it under the terms of the GNU General Public License, version 2.0,
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*/
 
#ifndef ROUTER_SRC_MYSQL_REST_SERVICE_SRC_MRS_OBSERVABILITY_ENTRITIES_MANAGER_H_
#define ROUTER_SRC_MYSQL_REST_SERVICE_SRC_MRS_OBSERVABILITY_ENTRITIES_MANAGER_H_
 
#include <cassert>
#include <memory>
#include <mutex>
#include <shared_mutex>
#include <vector>
 
#include "mrs/observability/entity.h"
 
namespace mrs {
namespace observability {
 
class EntitiesManager : private Common {
 public:
  using Snapshot = std::vector<std::pair<std::string, uint64_t>>;
 
  void record_entity(std::unique_ptr<Entity> &&entity) {
    auto id = entity->get_id();
 
    if (!(id < entities_.size())) {
      entities_.resize(id + 1);
    }
 
    assert(nullptr == entities_[id]);
 
    entities_[id] = std::move(entity);
    entities_[id]->clear();
  }
 
  const Snapshot &fetch_counters() {
    if (snapshoot_.size() != entities_.size()) {
      snapshoot_.resize(entities_.size());
      for (size_t i = 0; i < snapshoot_.size(); ++i) {
        snapshoot_[i].first =
            entities_[i] ? entities_[i]->get_name() : std::string();
      }
    }
 
    auto l = std::unique_lock(mutex);
 
    for (size_t i = 0; i < snapshoot_.size(); ++i) {
      if (!entities_[i]) {
        snapshoot_[i].second = 0;
        continue;
      }
      snapshoot_[i].second = entities_[i]->get_value_and_reset();
    }
 
    return snapshoot_;
  }
 
 private:
  Snapshot snapshoot_;
  std::vector<std::unique_ptr<Entity>> entities_;
};
 
}  // namespace observability
}  // namespace mrs
 
#endif  // ROUTER_SRC_MYSQL_REST_SERVICE_SRC_MRS_OBSERVABILITY_ENTRITIES_MANAGER_H_