146 lines
4.4 KiB
C++
146 lines
4.4 KiB
C++
/*
|
|
* Copyright 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/>.
|
|
*/
|
|
|
|
#include "key_reader.hh"
|
|
|
|
#include <boost/range/algorithm/heap_algorithm.hpp>
|
|
#include "utils/move.hh"
|
|
|
|
namespace stdx = std::experimental;
|
|
|
|
namespace {
|
|
|
|
class combined_reader final : public key_reader::impl {
|
|
std::vector<key_reader> _readers;
|
|
struct key_and_reader {
|
|
dht::decorated_key_opt dk;
|
|
key_reader* kr;
|
|
|
|
bool equal(const schema&, const dht::decorated_key_opt&) const;
|
|
};
|
|
std::vector<key_and_reader> _data;
|
|
dht::decorated_key_opt _last;
|
|
bool _inited = false;
|
|
schema_ptr _s;
|
|
static bool heap_compare(const schema& s, const key_and_reader&, const key_and_reader&);
|
|
public:
|
|
combined_reader(schema_ptr s, std::vector<key_reader> readers);
|
|
virtual future<dht::decorated_key_opt> operator()() override;
|
|
};
|
|
|
|
combined_reader::combined_reader(schema_ptr s, std::vector<key_reader> readers)
|
|
: _readers(std::move(readers))
|
|
, _s(s)
|
|
{
|
|
_data.reserve(_readers.size());
|
|
|
|
auto cmp = [this] (auto& x, auto& y) { return heap_compare(*_s, x, y); };
|
|
boost::range::make_heap(_data, cmp);
|
|
}
|
|
|
|
future<dht::decorated_key_opt> combined_reader::operator()()
|
|
{
|
|
auto cmp = [this] (auto& x, auto& y) { return heap_compare(*_s, x, y); };
|
|
if (!_inited) {
|
|
return parallel_for_each(_readers, [this] (key_reader& kr) {
|
|
return kr().then([this, &kr] (dht::decorated_key_opt dk) mutable {
|
|
if (dk) {
|
|
key_and_reader kar;
|
|
kar.kr = &kr;
|
|
kar.dk = std::move(dk);
|
|
_data.emplace_back(std::move(kar));
|
|
}
|
|
});
|
|
}).then([this, cmp] {
|
|
boost::make_heap(_data, cmp);
|
|
boost::pop_heap(_data, cmp);
|
|
_inited = true;
|
|
return operator()();
|
|
});
|
|
}
|
|
if (_data.empty()) {
|
|
return make_ready_future<dht::decorated_key_opt>();
|
|
}
|
|
auto& current = _data.back();
|
|
if (!current.dk || (_last && _last->equal(*_s, *current.dk))) {
|
|
return (*current.kr)().then([this, cmp] (dht::decorated_key_opt dk) mutable {
|
|
if (!dk) {
|
|
_data.pop_back();
|
|
} else {
|
|
_data.back().dk = std::move(dk);
|
|
boost::range::push_heap(_data, cmp);
|
|
}
|
|
boost::range::pop_heap(_data, cmp);
|
|
return operator()();
|
|
});
|
|
}
|
|
_last = move_and_disengage(current.dk);
|
|
return make_ready_future<dht::decorated_key_opt>(_last);
|
|
}
|
|
|
|
bool combined_reader::heap_compare(const schema& s, const key_and_reader& a, const key_and_reader& b)
|
|
{
|
|
if (!b.dk) {
|
|
return false;
|
|
}
|
|
if (!a.dk) {
|
|
return true;
|
|
}
|
|
return b.dk->less_compare(s, *a.dk);
|
|
}
|
|
|
|
bool combined_reader::key_and_reader::equal(const schema& s, const dht::decorated_key_opt& other) const
|
|
{
|
|
if (!dk && !other) {
|
|
return true;
|
|
} else if (!dk || !other) {
|
|
return false;
|
|
}
|
|
return dk->equal(s, *other);
|
|
}
|
|
|
|
class key_from_mutation_reader final : public key_reader::impl {
|
|
mutation_reader _reader;
|
|
public:
|
|
key_from_mutation_reader(mutation_reader&& reader) : _reader(std::move(reader)) { }
|
|
virtual future<dht::decorated_key_opt> operator()() override {
|
|
return _reader().then([] (streamed_mutation_opt&& mo) {
|
|
if (mo) {
|
|
return dht::decorated_key_opt(std::move(mo->decorated_key()));
|
|
} else {
|
|
return dht::decorated_key_opt();
|
|
}
|
|
});
|
|
}
|
|
};
|
|
|
|
}
|
|
|
|
key_reader make_combined_reader(schema_ptr s, std::vector<key_reader> readers)
|
|
{
|
|
return make_key_reader<combined_reader>(s, std::move(readers));
|
|
}
|
|
|
|
key_reader make_key_from_mutation_reader(mutation_reader&& reader)
|
|
{
|
|
return make_key_reader<key_from_mutation_reader>(std::move(reader));
|
|
}
|