text: /**
  *    Copyright (C) 2013 10gen 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.
  */
  
  #include "mongo/db/index/btree_access_method.h"
  
  #include <vector>
  
  #include "mongo/base/status.h"
  #include "mongo/base/status_with.h"
  #include "mongo/db/jsobj.h"
  #include "mongo/db/keypattern.h"
  
  namespace mongo {
  
  using std::vector;
  
  // Standard Btree implementation below.
  BtreeAccessMethod::BtreeAccessMethod(IndexCatalogEntry* btreeState, SortedDataInterface* btree)
      : IndexAccessMethod(btreeState, btree) {
      // The key generation wants these values.
      vector<const char*> fieldNames;
      vector<BSONElement> fixed;
  
      BSONObjIterator it(_descriptor->keyPattern());
      while (it.more()) {
          BSONElement elt = it.next();
          fieldNames.push_back(elt.fieldName());
          fixed.push_back(BSONElement());
      }
  
      _keyGenerator = BtreeKeyGenerator::make(_descriptor->version(),
                                              fieldNames,
                                              fixed,
                                              _descriptor->isSparse(),
                                              btreeState->getCollator());
      massert(16745, "Invalid index version for key generation.", _keyGenerator);
  }
  
  void BtreeAccessMethod::getKeys(const BSONObj& obj,
                                  BSONObjSet* keys,
                                  MultikeyPaths* multikeyPaths) const {
      _keyGenerator->getKeys(obj, keys, multikeyPaths);
  }
  
  }  // namespace mongo
  