////////////////////////////////////////////////////////////////////////////////
/// @brief wrapper for Aql transactions
///
/// @file
///
/// DISCLAIMER
///
/// Copyright 2004-2012 triAGENS GmbH, Cologne, Germany
///
/// Licensed under the Apache License, Version 2.0 (the "License");
/// you may not use this file except in compliance with the License.
/// You may obtain a copy of the License at
///
///     http://www.apache.org/licenses/LICENSE-2.0
///
/// Unless required by applicable law or agreed to in writing, software
/// distributed under the License is distributed on an "AS IS" BASIS,
/// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
/// See the License for the specific language governing permissions and
/// limitations under the License.
///
/// Copyright holder is triAGENS GmbH, Cologne, Germany
///
/// @author Jan Steemann
/// @author Copyright 2011-2012, triAGENS GmbH, Cologne, Germany
////////////////////////////////////////////////////////////////////////////////

#ifndef TRIAGENS_UTILS_AQL_TRANSACTION_H
#define TRIAGENS_UTILS_AQL_TRANSACTION_H 1

namespace triagens {
  namespace arango {

// -----------------------------------------------------------------------------
// --SECTION--                                              class AqlTransaction
// -----------------------------------------------------------------------------

    class Transaction {

////////////////////////////////////////////////////////////////////////////////
/// @addtogroup ArangoDB
/// @{
////////////////////////////////////////////////////////////////////////////////

// -----------------------------------------------------------------------------
// --SECTION--                                      constructors and destructors
// -----------------------------------------------------------------------------

////////////////////////////////////////////////////////////////////////////////
/// @addtogroup ArangoDB
/// @{
////////////////////////////////////////////////////////////////////////////////

      public:

////////////////////////////////////////////////////////////////////////////////
/// @brief create the transaction
////////////////////////////////////////////////////////////////////////////////

        AqlTransaction (const TRI_vocbase_col_t* vocbase, const vector<string>& collectionNames) : 
          Transaction(vocbase), _trx(0), _collectionNames(collectionNames) {
        }

////////////////////////////////////////////////////////////////////////////////
/// @brief end the transaction
////////////////////////////////////////////////////////////////////////////////

        ~AqlTransaction () {
          if (_trx != 0) {
            if (_trx->_status == TRI_TRANSACTION_RUNNING) {
              // auto abort
              abort();
            }

            TRI_FreeTransaction(_trx);
            _trx = 0;
          }
        }

      public:

        int begin () {
          if (_trx != 0) {
            // already started
            return TRI_ERROR_TRANSACTION_INVALD_STATE;
          }

          _trx = TRI_CreateTransaction(_vocbase->_transactionContext, TRI_TRANSACTION_READ_REPEATABLE, 0);
          if (_trx == 0) {
            return TRI_ERROR_OUT_OF_MEMORY;
          }
  
          for (size_t i = 0; i < _collectionNames.size(); ++i) {
            if (! TRI_AddCollectionTransaction(_trx, _collectionNames[i].c_str(), TRI_TRANSACTION_READ)) {
              return TRI_ERROR_INTERNAL;
            }
          }

          if (_trx->_status != TRI_TRANSACTION_CREATED) {
            return TRI_ERROR_TRANSACTION_INVALID_STATE;
          }

          int res = TRI_StartTransaction(_trx);
          return res;
        }

        int commit () {
          if (_trx == 0 || _trx->_status != TRI_TRANSACTION_RUNNING) {
            // not created or not running
            return TRI_ERROR_TRANSACTION_INVALD_STATE;
          }

          int res = TRI_FinishTransaction(_trx);
          
          return res;
        }

        int abort () {
          if (_trx == 0) {
            // transaction already ended or not created
            return TRI_ERROR_NO_ERROR;
          }

          if (_trx->_status != TRI_TRANSACTION_RUNNING) {
            return TRI_ERROR_TRANSACTION_INVALID_STATE;
          }

          int res = TRI_AbortTransaction(_trx);

          return res;
        }

      private:

        vector<string> _collectionNames;

////////////////////////////////////////////////////////////////////////////////
/// @}
////////////////////////////////////////////////////////////////////////////////

    };

  }
}

#endif

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