text: // lasterror.h
  
  /*    Copyright 2009 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.
   */
  
  #pragma once
  
  #include <boost/thread/tss.hpp>
  #include <string>
  
  #include "mongo/db/jsobj.h"
  #include "mongo/bson/oid.h"
  
  namespace mongo {
      class BSONObjBuilder;
      class Message;
  
      static const char kUpsertedFieldName[] = "upserted";
      static const char kGLEStatsFieldName[] = "$gleStats";
      static const char kGLEStatsLastOpTimeFieldName[] = "lastOpTime";
      static const char kGLEStatsElectionIdFieldName[] = "electionId";
  
      struct LastError {
          int code;
          std::string msg;
          enum UpdatedExistingType { NotUpdate, True, False } updatedExisting;
          // _id field value from inserted doc, returned as kUpsertedFieldName (above)
          BSONObj upsertedId;
          OID writebackId; // this shouldn't get reset so that old GLE are handled
          int writebackSince;
          long long nObjects;
          int nPrev;
          bool valid;
          bool disabled;
          void writeback(const OID& oid) {
              reset( true );
              writebackId = oid;
              writebackSince = 0;
          }
          void raiseError(int _code , const char *_msg) {
              reset( true );
              code = _code;
              msg = _msg;
          }
          void recordUpdate( bool _updateObjects , long long _nObjects , BSONObj _upsertedId ) {
              reset( true );
              nObjects = _nObjects;
              updatedExisting = _updateObjects ? True : False;
              if ( _upsertedId.valid() && _upsertedId.hasField(kUpsertedFieldName) )
                  upsertedId = _upsertedId;
  
          }
          void recordDelete( long long nDeleted ) {
              reset( true );
              nObjects = nDeleted;
          }
          LastError() {
              reset();
              writebackSince = 0;
          }
          void reset( bool _valid = false ) {
              code = 0;
              msg.clear();
              updatedExisting = NotUpdate;
              nObjects = 0;
              nPrev = 1;
              valid = _valid;
              disabled = false;
              upsertedId = BSONObj();
          }
  
          /**
           * @return if there is an err
           */
          bool appendSelf( BSONObjBuilder &b , bool blankErr = true );
  
          /**
           * appends fields which are not "error" related
           * this whole mechanism needs to be re-written
           * but needs a lot of real thought
           */
          void appendSelfStatus( BSONObjBuilder &b );
  
          struct Disabled : boost::noncopyable {
              Disabled( LastError * le ) {
                  _le = le;
                  if ( _le ) {
                      _prev = _le->disabled;
                      _le->disabled = true;
                  }
                  else {
                      _prev = false;
                  }
              }
  
              ~Disabled() {
                  if ( _le )
                      _le->disabled = _prev;
              }
  
              LastError * _le;
              bool _prev;
          };
  
          static LastError noError;
      };
  
      extern class LastErrorHolder {
      public:
          LastErrorHolder(){}
          ~LastErrorHolder();
  
          LastError * get( bool create = false );
          LastError * getSafe();
          LastError * _get( bool create = false ); // may return a disabled LastError
  
          void reset( LastError * le );
  
          /** ok to call more than once. */
          void initThread();
  
          int getID();
          
          void release();
  
          /** when db receives a message/request, call this */
          LastError * startRequest( Message& m , LastError * connectionOwned );
  
          void disconnect( int clientId );
  
          // used to disable lastError reporting while processing a killCursors message
          // disable causes get() to return 0.
          LastError *disableForCommand(); // only call once per command invocation!
      private:
          boost::thread_specific_ptr<LastError> _tl;
  
          struct Status {
              time_t time;
              LastError *lerr;
          };
      } lastError;
  
      void setLastError(int code , const char *msg);
  
  } // namespace mongo
  