#ifndef TRIAGENS_VOC_BASE_DOCUMENT_OPERATION_H
#define TRIAGENS_VOC_BASE_DOCUMENT_OPERATION_H 1

#include "Basics/Common.h"
#include "VocBase/document-collection.h"
#include "VocBase/headers.h"
#include "VocBase/voc-types.h"
#include "Wal/Marker.h"

struct TRI_transaction_collection_s;

namespace triagens {
  namespace wal {
    class Marker;

    struct DocumentOperation {
      enum class StatusType : uint8_t {
        CREATED,
        INDEXED,
        HANDLED,
        SWAPPED,
        REVERTED
      };

      DocumentOperation (Marker* marker,
                         bool freeMarker,
                         struct TRI_transaction_collection_s* trxCollection,
                         TRI_voc_document_operation_e type,
                         TRI_voc_rid_t rid)
        : marker(marker),
          trxCollection(trxCollection),
          header(nullptr),
          rid(rid),
          tick(0),
          type(type),
          status(StatusType::CREATED),
          freeMarker(freeMarker) {

        TRI_ASSERT(marker != nullptr);
      }

      ~DocumentOperation () {
        if (status == StatusType::HANDLED) {
          if (type == TRI_VOC_DOCUMENT_OPERATION_REMOVE) {
            TRI_document_collection_t* document = trxCollection->_collection->_collection;
            document->_headersPtr->release(header, false);  // PROTECTED by trx in trxCollection
          }
        }
        else if (status != StatusType::REVERTED) {
          revert();
        }

        if (marker != nullptr && freeMarker) {
          delete marker;
        }
      }

      DocumentOperation* swap () {
        DocumentOperation* copy = new DocumentOperation(marker, freeMarker, trxCollection, type, rid);
        copy->tick = tick;
        copy->header = header;
        copy->oldHeader = oldHeader;
        copy->status = status;

        type = TRI_VOC_DOCUMENT_OPERATION_UNKNOWN;
        freeMarker = false;
        marker = nullptr;
        header = nullptr;
        status = StatusType::SWAPPED;

        return copy;
      }

      void init () {
        if (type == TRI_VOC_DOCUMENT_OPERATION_UPDATE ||
            type == TRI_VOC_DOCUMENT_OPERATION_REMOVE) {
          // copy the old header into a safe area
          TRI_ASSERT(header != nullptr);
          oldHeader = *header;
        }
      }

      void indexed () {
        TRI_ASSERT(status == StatusType::CREATED);
        status = StatusType::INDEXED;
      }

      void handle () {
        TRI_ASSERT(header != nullptr);
        TRI_ASSERT(status == StatusType::INDEXED);

        TRI_document_collection_t* document = trxCollection->_collection->_collection;

        if (type == TRI_VOC_DOCUMENT_OPERATION_UPDATE) {
          // move header to the end of the list
          document->_headersPtr->moveBack(header, &oldHeader);  // PROTECTED by trx in trxCollection
        }

        // free the local marker buffer
        marker->freeBuffer();
        status = StatusType::HANDLED;
      }

      void revert () {
        if (header == nullptr || status == StatusType::SWAPPED || status == StatusType::REVERTED) {
          return;
        }

        TRI_document_collection_t* document = trxCollection->_collection->_collection;

        if (status == StatusType::INDEXED || status == StatusType::HANDLED) {
          TRI_RollbackOperationDocumentCollection(document, type, header, &oldHeader);
        }

        if (type == TRI_VOC_DOCUMENT_OPERATION_INSERT) {
          document->_headersPtr->release(header, true);  // PROTECTED by trx in trxCollection
        }
        else if (type == TRI_VOC_DOCUMENT_OPERATION_UPDATE) {
          document->_headersPtr->move(header, &oldHeader);  // PROTECTED by trx in trxCollection
          header->copy(oldHeader);
        }
        else if (type == TRI_VOC_DOCUMENT_OPERATION_REMOVE) {
          if (status != StatusType::CREATED) {
            document->_headersPtr->relink(header, &oldHeader); // PROTECTED by trx in trxCollection 
          }
        }

        status = StatusType::REVERTED;
      }

      Marker*                               marker;
      struct TRI_transaction_collection_s*  trxCollection;
      TRI_doc_mptr_t*                       header;
      TRI_doc_mptr_copy_t                   oldHeader;
      TRI_voc_rid_t const                   rid;
      TRI_voc_tick_t                        tick;
      TRI_voc_document_operation_e          type;
      StatusType                            status;
      bool                                  freeMarker;
    };
  }
}

#endif

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