Files
scylladb/gms/feature.hh
Asias He 2b1ebc4719 gossip: Introduce gms:features::enable helper
Add the helper function to enable the a feature and log the feature is
enabled.

When a feature is enabled, we see

INFO  2016-12-15 11:29:32,443 [shard 0] gossip - Feature LARGE_PARTITIONS is enabled
INFO  2016-12-15 11:29:32,443 [shard 0] gossip - Feature RANGE_TOMBSTONES is enabled

in the log.
2016-12-15 16:33:10 +08:00

59 lines
1.6 KiB
C++

/*
* Copyright (C) 2016 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
namespace gms {
/**
* A gossip feature tracks whether all the nodes the current one is
* aware of support the specified feature.
*
* A feature should only be created once the gossiper is available.
*/
class feature final {
sstring _name;
bool _enabled;
friend class gossiper;
public:
explicit feature(sstring name, bool enabled = false);
~feature();
feature()
: _enabled(false)
{ }
feature(const feature& other)
: feature(other._name, other._enabled)
{ }
void enable();
feature& operator=(feature other);
const sstring& name() const {
return _name;
}
explicit operator bool() const {
return _enabled;
}
friend inline std::ostream& operator<<(std::ostream& os, const feature& f) {
return os << "{ gossip feature = " << f._name << " }";
}
};
} // namespace gms