catalog_balancer.h

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#ifndef CVMFS_CATALOG_BALANCER_H_
#define CVMFS_CATALOG_BALANCER_H_

#include <string>
#include <vector>

#include "catalog_mgr.h"
#include "directory_entry.h"


namespace catalog {

template <class CatalogMgrT>
class CatalogBalancer {
 public:
  typedef typename CatalogMgrT::catalog_t catalog_t;
  explicit CatalogBalancer(CatalogMgrT *catalog_mgr)
    : catalog_mgr_(catalog_mgr) { }

  void Balance(catalog_t *catalog);

 private:
  struct VirtualNode {
    std::vector<VirtualNode> children;
    unsigned weight;
    DirectoryEntry dirent;
    std::string path;
    bool is_new_nested_catalog;

    void ExtractChildren(CatalogMgrT *catalog_mgr);
    void FixWeight();
    VirtualNode(const std::string &path, CatalogMgrT *catalog_mgr)
      : children(), weight(1), dirent(), path(path),
        is_new_nested_catalog(false) {
      catalog_mgr->LookupPath(path, kLookupDefault, &dirent);
    }
    VirtualNode(const std::string &path, const DirectoryEntry &dirent,
                CatalogMgrT *catalog_mgr)
      : children(), weight(1), dirent(dirent), path(path),
        is_new_nested_catalog(false) {
      if (!IsCatalog() && IsDirectory())
        ExtractChildren(catalog_mgr);
    }
    bool IsDirectory() { return dirent.IsDirectory(); }
    bool IsCatalog() { return is_new_nested_catalog ||
        dirent.IsNestedCatalogMountpoint(); }
  };
  typedef typename CatalogBalancer<CatalogMgrT>::VirtualNode virtual_node_t;

  void PartitionOptimally(VirtualNode *virtual_node);
  void AddCatalogMarker(std::string path);
  DirectoryEntryBase MakeEmptyDirectoryEntryBase(std::string name,
                                                 uid_t uid,
                                                 gid_t gid);
  static VirtualNode *MaxChild(VirtualNode *virtual_node);
  void AddCatalog(VirtualNode *child_node);

  CatalogMgrT *catalog_mgr_;
};

}  // namespace catalog

#include "catalog_balancer_impl.h"

#endif  // CVMFS_CATALOG_BALANCER_H_