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arangodb/arangod/MMFiles/MMFilesWalMarker.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_MMFILES_MMFILES_WAL_MARKER_H
#define ARANGOD_MMFILES_MMFILES_WAL_MARKER_H 1
#include "Basics/Common.h"
#include "Basics/encoding.h"
#include "MMFiles/MMFilesDatafile.h"
#include "MMFiles/MMFilesDatafileHelper.h"
#include "VocBase/voc-types.h"
#include <velocypack/Slice.h>
namespace arangodb {
/// @brief abstract base class for all markers
class MMFilesWalMarker {
private:
MMFilesWalMarker& operator=(MMFilesWalMarker const&) = delete;
MMFilesWalMarker(MMFilesWalMarker&&) = delete;
MMFilesWalMarker(MMFilesWalMarker const&) = delete;
protected:
MMFilesWalMarker() = default;
public:
virtual ~MMFilesWalMarker() {}
/// @brief returns the marker type
virtual MMFilesMarkerType type() const = 0;
/// @brief returns the datafile id the marker comes from
/// this should be 0 for new markers, but contain the actual
/// datafile id for an existing marker during recovery
virtual TRI_voc_fid_t fid() const = 0;
/// @brief return the total size of the marker, including the header
virtual uint32_t size() const = 0;
/// @brief store the marker in the memory region starting at mem
/// the region is guaranteed to be big enough to hold size() bytes
virtual void store(char* mem) const = 0;
/// @brief a pointer to the beginning of the VPack payload
virtual uint8_t* vpack() const {
// not implemented for base marker type
TRI_ASSERT(false);
return nullptr;
}
};
/// @brief an envelope that contains a pointer to an existing marker
/// this type is used during recovery only, to represent existing markers
class MMFilesMarkerEnvelope : public MMFilesWalMarker {
public:
MMFilesMarkerEnvelope(MMFilesMarker const* other, TRI_voc_fid_t fid)
: _other(other),
_fid(fid),
_size(other->getSize()) {
// we must always have a datafile id, and a reasonable marker size
TRI_ASSERT(_fid > 0);
TRI_ASSERT(_size >= sizeof(MMFilesMarker));
}
~MMFilesMarkerEnvelope() = default;
/// @brief returns the marker type
MMFilesMarkerType type() const override final {
// simply return the wrapped marker's type
return _other->getType();
}
/// @brief returns the datafile id the marker comes from
TRI_voc_fid_t fid() const override final { return _fid; }
/// @brief a pointer the beginning of the VPack payload
uint8_t* vpack() const override final {
return const_cast<uint8_t*>(reinterpret_cast<uint8_t const*>(_other) + MMFilesDatafileHelper::VPackOffset(type()));
}
/// @brief a pointer to the beginning of the wrapped marker
void const* mem() const {
return static_cast<void const*>(_other);
}
/// @brief return the size of the wrapped marker
uint32_t size() const override final { return _size; }
/// @brief store the marker in the memory region starting at mem
void store(char* mem) const override final {
// intentionally nothing... should never be called for MarkerEnvelopes,
// as they represent existing markers from the WAL that do not need to
// be written again!
TRI_ASSERT(false);
}
private:
MMFilesMarker const* _other;
TRI_voc_fid_t _fid;
uint32_t _size;
};
/// @brief a marker type that is used when inserting new documents,
/// updating/replacing or removing documents
class MMFilesCrudMarker : public MMFilesWalMarker {
public:
MMFilesCrudMarker(MMFilesMarkerType type,
TRI_voc_tid_t transactionId,
arangodb::velocypack::Slice const& data)
: _transactionId(transactionId),
_data(data),
_type(type) {}
~MMFilesCrudMarker() = default;
/// @brief returns the marker type
MMFilesMarkerType type() const override final { return _type; }
/// @brief returns the datafile id
/// this is always 0 for this type of marker, as the marker is not
/// yet in any datafile
TRI_voc_fid_t fid() const override final { return 0; }
/// @brief returns the marker size
uint32_t size() const override final {
return static_cast<uint32_t>(MMFilesDatafileHelper::VPackOffset(_type) + _data.byteSize());
}
/// @brief store the marker in the memory region starting at mem
void store(char* mem) const override final {
// store transaction id
encoding::storeNumber<decltype(_transactionId)>(reinterpret_cast<uint8_t*>(mem) + MMFilesDatafileHelper::TransactionIdOffset(_type), _transactionId, sizeof(decltype(_transactionId)));
// store VPack
memcpy(mem + MMFilesDatafileHelper::VPackOffset(_type), _data.begin(), static_cast<size_t>(_data.byteSize()));
}
/// @brief a pointer the beginning of the VPack payload
uint8_t* vpack() const override final { return const_cast<uint8_t*>(_data.begin()); }
private:
TRI_voc_tid_t _transactionId;
arangodb::velocypack::Slice _data;
MMFilesMarkerType _type;
};
/// @brief a marker used for database-related operations
class MMFilesDatabaseMarker : public MMFilesWalMarker {
public:
MMFilesDatabaseMarker(MMFilesMarkerType type,
TRI_voc_tick_t databaseId,
arangodb::velocypack::Slice const& data)
: _databaseId(databaseId),
_data(data),
_type(type) {
TRI_ASSERT(databaseId > 0);
}
~MMFilesDatabaseMarker() = default;
/// @brief returns the marker type
MMFilesMarkerType type() const override final { return _type; }
/// @brief returns the datafile id
/// this is always 0 for this type of marker, as the marker is not
/// yet in any datafile
TRI_voc_fid_t fid() const override final { return 0; }
/// @brief returns the marker size
uint32_t size() const override final {
return static_cast<uint32_t>(MMFilesDatafileHelper::VPackOffset(_type) + _data.byteSize());
}
/// @brief store the marker in the memory region starting at mem
void store(char* mem) const override final {
// store database id
encoding::storeNumber<decltype(_databaseId)>(reinterpret_cast<uint8_t*>(mem) + MMFilesDatafileHelper::DatabaseIdOffset(_type), _databaseId, sizeof(decltype(_databaseId)));
// store VPack
memcpy(mem + MMFilesDatafileHelper::VPackOffset(_type), _data.begin(), static_cast<size_t>(_data.byteSize()));
}
private:
TRI_voc_tick_t _databaseId;
arangodb::velocypack::Slice _data;
MMFilesMarkerType _type;
};
/// @brief a marker used for collection-related operations
class MMFilesCollectionMarker : public MMFilesWalMarker {
public:
MMFilesCollectionMarker(MMFilesMarkerType type,
TRI_voc_tick_t databaseId,
TRI_voc_cid_t collectionId,
arangodb::velocypack::Slice const& data)
: _databaseId(databaseId),
_collectionId(collectionId),
_data(data.begin()),
_type(type) {
TRI_ASSERT(databaseId > 0);
TRI_ASSERT(collectionId > 0);
}
~MMFilesCollectionMarker() = default;
/// @brief returns the marker type
MMFilesMarkerType type() const override final { return _type; }
/// @brief returns the datafile id
/// this is always 0 for this type of marker, as the marker is not
/// yet in any datafile
TRI_voc_fid_t fid() const override final { return 0; }
/// @brief returns the marker size
uint32_t size() const override final {
return static_cast<uint32_t>(MMFilesDatafileHelper::VPackOffset(_type) + _data.byteSize());
}
/// @brief store the marker in the memory region starting at mem
void store(char* mem) const override final {
// store database id
encoding::storeNumber<decltype(_databaseId)>(reinterpret_cast<uint8_t*>(mem) + MMFilesDatafileHelper::DatabaseIdOffset(_type), _databaseId, sizeof(decltype(_databaseId)));
// store collection id
encoding::storeNumber<decltype(_collectionId)>(reinterpret_cast<uint8_t*>(mem) + MMFilesDatafileHelper::CollectionIdOffset(_type), _collectionId, sizeof(decltype(_collectionId)));
// store VPack
memcpy(mem + MMFilesDatafileHelper::VPackOffset(_type), _data.begin(), static_cast<size_t>(_data.byteSize()));
}
private:
TRI_voc_tick_t _databaseId;
TRI_voc_cid_t _collectionId;
arangodb::velocypack::Slice _data;
MMFilesMarkerType _type;
};
/// @brief a marker used for view-related operations
class MMFilesViewMarker : public MMFilesWalMarker {
public:
MMFilesViewMarker(MMFilesMarkerType type,
TRI_voc_tick_t databaseId,
TRI_voc_cid_t viewId,
arangodb::velocypack::Slice const& data)
: _databaseId(databaseId),
_viewId(viewId),
_data(data.begin()),
_type(type) {
TRI_ASSERT(databaseId > 0);
TRI_ASSERT(viewId > 0);
}
~MMFilesViewMarker() = default;
/// @brief returns the marker type
MMFilesMarkerType type() const override final { return _type; }
/// @brief returns the datafile id
/// this is always 0 for this type of marker, as the marker is not
/// yet in any datafile
TRI_voc_fid_t fid() const override final { return 0; }
/// @brief returns the marker size
uint32_t size() const override final {
return static_cast<uint32_t>(MMFilesDatafileHelper::VPackOffset(_type) + _data.byteSize());
}
/// @brief store the marker in the memory region starting at mem
void store(char* mem) const override final {
// store database id
encoding::storeNumber<decltype(_databaseId)>(reinterpret_cast<uint8_t*>(mem) + MMFilesDatafileHelper::DatabaseIdOffset(_type), _databaseId, sizeof(decltype(_databaseId)));
// store view id
encoding::storeNumber<decltype(_viewId)>(reinterpret_cast<uint8_t*>(mem) + MMFilesDatafileHelper::ViewIdOffset(_type), _viewId, sizeof(decltype(_viewId)));
// store VPack
memcpy(mem + MMFilesDatafileHelper::VPackOffset(_type), _data.begin(), static_cast<size_t>(_data.byteSize()));
}
private:
TRI_voc_tick_t _databaseId;
TRI_voc_cid_t _viewId;
arangodb::velocypack::Slice _data;
MMFilesMarkerType _type;
};
/// @brief a marker used for transaction-related operations
class MMFilesTransactionMarker : public MMFilesWalMarker {
public:
MMFilesTransactionMarker(MMFilesMarkerType type,
TRI_voc_tick_t databaseId,
TRI_voc_tid_t transactionId)
: _databaseId(databaseId),
_transactionId(transactionId),
_type(type) {
TRI_ASSERT(databaseId > 0);
TRI_ASSERT(transactionId > 0);
}
~MMFilesTransactionMarker() = default;
/// @brief returns the marker type
MMFilesMarkerType type() const override final { return _type; }
/// @brief returns the datafile id
/// this is always 0 for this type of marker, as the marker is not
/// yet in any datafile
TRI_voc_fid_t fid() const override final { return 0; }
/// @brief returns the marker size
uint32_t size() const override final {
// these markers do not have any VPack payload
return static_cast<uint32_t>(MMFilesDatafileHelper::VPackOffset(_type));
}
/// @brief store the marker in the memory region starting at mem
void store(char* mem) const override final {
// store database id
encoding::storeNumber<decltype(_databaseId)>(reinterpret_cast<uint8_t*>(mem) + MMFilesDatafileHelper::DatabaseIdOffset(_type), _databaseId, sizeof(decltype(_databaseId)));
// store transaction id
encoding::storeNumber<decltype(_transactionId)>(reinterpret_cast<uint8_t*>(mem) + MMFilesDatafileHelper::TransactionIdOffset(_type), _transactionId, sizeof(decltype(_transactionId)));
}
private:
TRI_voc_tick_t _databaseId;
TRI_voc_tid_t _transactionId;
MMFilesMarkerType _type;
};
}
#endif