text: // repair_cursor.cpp
  
  /**
  *    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.
  */
  
  #include "mongo/platform/basic.h"
  
  #include <memory>
  
  #include "mongo/db/auth/authorization_session.h"
  #include "mongo/db/catalog/collection.h"
  #include "mongo/db/client.h"
  #include "mongo/db/commands.h"
  #include "mongo/db/db_raii.h"
  #include "mongo/db/exec/multi_iterator.h"
  #include "mongo/db/query/cursor_response.h"
  
  namespace mongo {
  
  using std::string;
  
  class RepairCursorCmd : public Command {
  public:
      RepairCursorCmd() : Command("repairCursor") {}
  
      virtual bool isWriteCommandForConfigServer() const {
          return false;
      }
      virtual bool slaveOk() const {
          return true;
      }
  
      virtual Status checkAuthForCommand(ClientBasic* client,
                                         const std::string& dbname,
                                         const BSONObj& cmdObj) {
          ActionSet actions;
          actions.addAction(ActionType::find);
          Privilege p(parseResourcePattern(dbname, cmdObj), actions);
          if (AuthorizationSession::get(client)->isAuthorizedForPrivilege(p))
              return Status::OK();
          return Status(ErrorCodes::Unauthorized, "Unauthorized");
      }
  
      virtual bool run(OperationContext* txn,
                       const string& dbname,
                       BSONObj& cmdObj,
                       int options,
                       string& errmsg,
                       BSONObjBuilder& result) {
          NamespaceString ns(parseNs(dbname, cmdObj));
  
          AutoGetCollectionForRead ctx(txn, ns.ns());
  
          Collection* collection = ctx.getCollection();
          if (!collection) {
              return appendCommandStatus(
                  result, Status(ErrorCodes::NamespaceNotFound, "ns does not exist: " + ns.ns()));
          }
  
          auto cursor = collection->getRecordStore()->getCursorForRepair(txn);
          if (!cursor) {
              return appendCommandStatus(
                  result, Status(ErrorCodes::CommandNotSupported, "repair iterator not supported"));
          }
  
          std::unique_ptr<WorkingSet> ws(new WorkingSet());
          std::unique_ptr<MultiIteratorStage> stage(
              new MultiIteratorStage(txn, ws.get(), collection));
          stage->addIterator(std::move(cursor));
  
          auto statusWithPlanExecutor = PlanExecutor::make(
              txn, std::move(ws), std::move(stage), collection, PlanExecutor::YIELD_AUTO);
          invariant(statusWithPlanExecutor.isOK());
          std::unique_ptr<PlanExecutor> exec = std::move(statusWithPlanExecutor.getValue());
  
          // 'exec' will be used in getMore(). It was automatically registered on construction
          // due to the auto yield policy, so it could yield during plan selection. We deregister
          // it now so that it can be registed with ClientCursor.
          exec->deregisterExec();
          exec->saveState();
          exec->detachFromOperationContext();
  
          // ClientCursors' constructor inserts them into a global map that manages their
          // lifetimes. That is why the next line isn't leaky.
          ClientCursor* cc =
              new ClientCursor(collection->getCursorManager(),
                               exec.release(),
                               ns.ns(),
                               txn->recoveryUnit()->isReadingFromMajorityCommittedSnapshot());
  
          appendCursorResponseObject(cc->cursorid(), ns.ns(), BSONArray(), &result);
  
          return true;
      }
  } repairCursorCmd;
  }
  