include/colmap/base/database_cache.h

// Copyright (c) 2022, ETH Zurich and UNC Chapel Hill.
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// Author: Johannes L. Schoenberger (jsch-at-demuc-dot-de)

#ifndef COLMAP_SRC_BASE_DATABASE_CACHE_H_
#define COLMAP_SRC_BASE_DATABASE_CACHE_H_

#include <string>
#include <unordered_map>
#include <unordered_set>
#include <vector>

#include <Eigen/Core>

#include "base/camera.h"
#include "base/camera_models.h"
#include "base/correspondence_graph.h"
#include "base/database.h"
#include "base/image.h"
#include "util/alignment.h"
#include "util/types.h"

namespace colmap {

// A class that caches the contents of the database in memory, used to quickly
// create new reconstruction instances when multiple models are reconstructed.
class DatabaseCache {
 public:
  DatabaseCache();

  // Get number of objects.
  inline size_t NumCameras() const;
  inline size_t NumImages() const;

  // Get specific objects.
  inline class Camera& Camera(const camera_t camera_id);
  inline const class Camera& Camera(const camera_t camera_id) const;
  inline class Image& Image(const image_t image_id);
  inline const class Image& Image(const image_t image_id) const;

  // Get all objects.
  inline const EIGEN_STL_UMAP(camera_t, class Camera) & Cameras() const;
  inline const EIGEN_STL_UMAP(image_t, class Image) & Images() const;

  // Check whether specific object exists.
  inline bool ExistsCamera(const camera_t camera_id) const;
  inline bool ExistsImage(const image_t image_id) const;

  // Get reference to correspondence graph.
  inline const class CorrespondenceGraph& CorrespondenceGraph() const;

  // Manually add data to cache.
  void AddCamera(class Camera camera);
  void AddImage(class Image image);

  // Load cameras, images, features, and matches from database.
  //
  // @param database              Source database from which to load data.
  // @param min_num_matches       Only load image pairs with a minimum number
  //                              of matches.
  // @param ignore_watermarks     Whether to ignore watermark image pairs.
  // @param image_names           Whether to use only load the data for a subset
  //                              of the images. All images are used if empty.
  void Load(const Database& database, const size_t min_num_matches,
            const bool ignore_watermarks,
            const std::unordered_set<std::string>& image_names);

  // Find specific image by name. Note that this uses linear search.
  const class Image* FindImageWithName(const std::string& name) const;

 private:
  class CorrespondenceGraph correspondence_graph_;

  EIGEN_STL_UMAP(camera_t, class Camera) cameras_;
  EIGEN_STL_UMAP(image_t, class Image) images_;
};

////////////////////////////////////////////////////////////////////////////////
// Implementation
////////////////////////////////////////////////////////////////////////////////

size_t DatabaseCache::NumCameras() const { return cameras_.size(); }
size_t DatabaseCache::NumImages() const { return images_.size(); }

class Camera& DatabaseCache::Camera(const camera_t camera_id) {
  return cameras_.at(camera_id);
}

const class Camera& DatabaseCache::Camera(const camera_t camera_id) const {
  return cameras_.at(camera_id);
}

class Image& DatabaseCache::Image(const image_t image_id) {
  return images_.at(image_id);
}

const class Image& DatabaseCache::Image(const image_t image_id) const {
  return images_.at(image_id);
}

const EIGEN_STL_UMAP(camera_t, class Camera) & DatabaseCache::Cameras() const {
  return cameras_;
}

const EIGEN_STL_UMAP(image_t, class Image) & DatabaseCache::Images() const {
  return images_;
}

bool DatabaseCache::ExistsCamera(const camera_t camera_id) const {
  return cameras_.find(camera_id) != cameras_.end();
}

bool DatabaseCache::ExistsImage(const image_t image_id) const {
  return images_.find(image_id) != images_.end();
}

inline const class CorrespondenceGraph& DatabaseCache::CorrespondenceGraph()
    const {
  return correspondence_graph_;
}

}  // namespace colmap

#endif  // COLMAP_SRC_BASE_DATABASE_CACHE_H_