text: // bson_collection_catalog_entry.h
  
  /**
   *    Copyright (C) 2014 MongoDB Inc.
   *
   *    This program is free software: you can redistribute it and/or  modify
   *    it under the terms of the GNU Affero General Public License, version 3,
   *    as published by the Free Software Foundation.
   *
   *    This program is distributed in the hope that it will be useful,
   *    but WITHOUT ANY WARRANTY; without even the implied warranty of
   *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   *    GNU Affero General Public License for more details.
   *
   *    You should have received a copy of the GNU Affero General Public License
   *    along with this program.  If not, see <http://www.gnu.org/licenses/>.
   *
   *    As a special exception, the copyright holders give permission to link the
   *    code of portions of this program with the OpenSSL library under certain
   *    conditions as described in each individual source file and distribute
   *    linked combinations including the program with the OpenSSL library. You
   *    must comply with the GNU Affero General Public License in all respects for
   *    all of the code used other than as permitted herein. If you modify file(s)
   *    with this exception, you may extend this exception to your version of the
   *    file(s), but you are not obligated to do so. If you do not wish to do so,
   *    delete this exception statement from your version. If you delete this
   *    exception statement from all source files in the program, then also delete
   *    it in the license file.
   */
  
  #pragma once
  
  #include <string>
  #include <vector>
  
  #include "mongo/db/catalog/collection_catalog_entry.h"
  #include "mongo/db/index/multikey_paths.h"
  
  namespace mongo {
  
  /**
   * This is a helper class for any storage engine that wants to store catalog information
   * as BSON. It is totally optional to use this.
   */
  class BSONCollectionCatalogEntry : public CollectionCatalogEntry {
  public:
      BSONCollectionCatalogEntry(StringData ns);
  
      virtual ~BSONCollectionCatalogEntry() {}
  
      virtual CollectionOptions getCollectionOptions(OperationContext* txn) const;
  
      virtual int getTotalIndexCount(OperationContext* txn) const;
  
      virtual int getCompletedIndexCount(OperationContext* txn) const;
  
      virtual BSONObj getIndexSpec(OperationContext* txn, StringData idxName) const;
  
      virtual void getAllIndexes(OperationContext* txn, std::vector<std::string>* names) const;
  
      virtual bool isIndexMultikey(OperationContext* txn,
                                   StringData indexName,
                                   MultikeyPaths* multikeyPaths) const;
  
      virtual RecordId getIndexHead(OperationContext* txn, StringData indexName) const;
  
      virtual bool isIndexReady(OperationContext* txn, StringData indexName) const;
  
      // ------ for implementors
  
      struct IndexMetaData {
          IndexMetaData() {}
          IndexMetaData(BSONObj s, bool r, RecordId h, bool m)
              : spec(s), ready(r), head(h), multikey(m) {}
  
          void updateTTLSetting(long long newExpireSeconds);
  
          std::string name() const {
              return spec["name"].String();
          }
  
          BSONObj spec;
          bool ready;
          RecordId head;
          bool multikey;
  
          // If non-empty, 'multikeyPaths' is a vector with size equal to the number of elements in
          // the index key pattern. Each element in the vector is an ordered set of positions
          // (starting at 0) into the corresponding indexed field that represent what prefixes of the
          // indexed field cause the index to be multikey.
          MultikeyPaths multikeyPaths;
      };
  
      struct MetaData {
          void parse(const BSONObj& obj);
          BSONObj toBSON() const;
  
          int findIndexOffset(StringData name) const;
  
          /**
           * Removes information about an index from the MetaData. Returns true if an index
           * called name existed and was deleted, and false otherwise.
           */
          bool eraseIndex(StringData name);
  
          void rename(StringData toNS);
  
          std::string ns;
          CollectionOptions options;
          std::vector<IndexMetaData> indexes;
      };
  
  protected:
      virtual MetaData _getMetaData(OperationContext* txn) const = 0;
  };
  }
  