Files
scylladb/atomic_cell_or_collection.hh
2017-03-02 09:05:11 +00:00

75 lines
2.7 KiB
C++

/*
* Copyright (C) 2015 ScyllaDB
*/
/*
* This file is part of Scylla.
*
* Scylla is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* Scylla 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with Scylla. If not, see <http://www.gnu.org/licenses/>.
*/
#pragma once
#include "atomic_cell.hh"
#include "schema.hh"
#include "hashing.hh"
// A variant type that can hold either an atomic_cell, or a serialized collection.
// Which type is stored is determined by the schema.
// Has an "empty" state.
// Objects moved-from are left in an empty state.
class atomic_cell_or_collection final {
managed_bytes _data;
private:
atomic_cell_or_collection(managed_bytes&& data) : _data(std::move(data)) {}
public:
atomic_cell_or_collection() = default;
atomic_cell_or_collection(atomic_cell ac) : _data(std::move(ac._data)) {}
static atomic_cell_or_collection from_atomic_cell(atomic_cell data) { return { std::move(data._data) }; }
atomic_cell_view as_atomic_cell() const { return atomic_cell_view::from_bytes(_data); }
atomic_cell_ref as_atomic_cell_ref() { return { _data }; }
atomic_cell_mutable_view as_mutable_atomic_cell() { return atomic_cell_mutable_view::from_bytes(_data); }
atomic_cell_or_collection(collection_mutation cm) : _data(std::move(cm.data)) {}
explicit operator bool() const {
return !_data.empty();
}
bool can_use_mutable_view() const {
return !_data.is_fragmented();
}
static atomic_cell_or_collection from_collection_mutation(collection_mutation data) {
return std::move(data.data);
}
collection_mutation_view as_collection_mutation() const {
return collection_mutation_view{_data};
}
bytes_view serialize() const {
return _data;
}
bool operator==(const atomic_cell_or_collection& other) const {
return _data == other._data;
}
template<typename Hasher>
void feed_hash(Hasher& h, const column_definition& def) const {
if (def.is_atomic()) {
::feed_hash(h, as_atomic_cell(), def);
} else {
::feed_hash(h, as_collection_mutation(), def);
}
}
size_t external_memory_usage() const {
return _data.external_memory_usage();
}
friend std::ostream& operator<<(std::ostream&, const atomic_cell_or_collection&);
};