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arangodb/arangod/VocBase/update-policy.h

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////////////////////////////////////////////////////////////////////////////////
/// DISCLAIMER
///
/// Copyright 2014-2016 ArangoDB GmbH, Cologne, Germany
/// Copyright 2004-2014 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 ArangoDB GmbH, Cologne, Germany
///
/// @author Jan Steemann
////////////////////////////////////////////////////////////////////////////////
#ifndef ARANGOD_VOC_BASE_UPDATE_POLICY_H
#define ARANGOD_VOC_BASE_UPDATE_POLICY_H 1
#include "Basics/Common.h"
#include "VocBase/vocbase.h"
////////////////////////////////////////////////////////////////////////////////
/// @brief update and delete policy
////////////////////////////////////////////////////////////////////////////////
typedef enum {
TRI_DOC_UPDATE_ERROR,
TRI_DOC_UPDATE_LAST_WRITE,
TRI_DOC_UPDATE_ONLY_IF_NEWER,
TRI_DOC_UPDATE_ILLEGAL
} TRI_doc_update_policy_e;
////////////////////////////////////////////////////////////////////////////////
/// @brief policy container
////////////////////////////////////////////////////////////////////////////////
class TRI_doc_update_policy_t {
public:
TRI_doc_update_policy_t(TRI_doc_update_policy_t const&) = delete;
TRI_doc_update_policy_t& operator=(TRI_doc_update_policy_t const&) = delete;
TRI_doc_update_policy_t() = delete;
TRI_doc_update_policy_t(TRI_doc_update_policy_e policy,
TRI_voc_rid_t expectedRid, TRI_voc_rid_t* previousRid)
: _expectedRid(expectedRid), _previousRid(previousRid), _policy(policy) {}
public:
//////////////////////////////////////////////////////////////////////////////
/// @brief update the expected revision id in an existing policy object
//////////////////////////////////////////////////////////////////////////////
inline void setExpectedRevision(TRI_voc_rid_t rid) { _expectedRid = rid; }
//////////////////////////////////////////////////////////////////////////////
/// @brief compare revision of found document with revision specified in
/// policy
/// this will also store the actual revision id found in the database in the
/// context variable _previousRid, but only if this is not NULL
//////////////////////////////////////////////////////////////////////////////
int check(TRI_voc_rid_t actualRid) const {
// store previous revision
if (_previousRid != nullptr) {
*(_previousRid) = actualRid;
}
// check policy
switch (_policy) {
case TRI_DOC_UPDATE_ERROR:
if (_expectedRid != 0 && _expectedRid != actualRid) {
return TRI_ERROR_ARANGO_CONFLICT;
}
// fallthrough
break;
case TRI_DOC_UPDATE_ILLEGAL:
return TRI_ERROR_INTERNAL;
case TRI_DOC_UPDATE_LAST_WRITE:
return TRI_ERROR_NO_ERROR;
case TRI_DOC_UPDATE_ONLY_IF_NEWER:
if (actualRid > _expectedRid) {
return TRI_ERROR_ARANGO_CONFLICT;
}
// fallthrough
break;
}
return TRI_ERROR_NO_ERROR;
}
private:
TRI_voc_rid_t _expectedRid; // the expected revision id of a document. only
// used if set and for update/delete
TRI_voc_rid_t* _previousRid; // a variable that the previous revsion id found
// in the database will be pushed into. only
// used if set and for update/delete
TRI_doc_update_policy_e _policy; // the update policy
};
#endif