f3eade2f62
Drop the AGPL license in favor of a source-available license. See the blog post [1] for details. [1] https://www.scylladb.com/2024/12/18/why-were-moving-to-a-source-available-license/
72 lines
2.1 KiB
C++
72 lines
2.1 KiB
C++
/*
|
|
* Copyright (C) 2020-present ScyllaDB
|
|
*/
|
|
|
|
/*
|
|
* SPDX-License-Identifier: LicenseRef-ScyllaDB-Source-Available-1.0
|
|
*/
|
|
|
|
#pragma once
|
|
|
|
#include "readers/clustering_combined.hh"
|
|
#include "readers/mutation_reader.hh"
|
|
|
|
/*
|
|
* Single-partition reader, a lower bound and an upper bound for the set of positions
|
|
* of fragments returned by the reader. The bounds don't need to be exact.
|
|
*/
|
|
struct reader_bounds {
|
|
mutation_reader r;
|
|
position_in_partition lower;
|
|
position_in_partition upper;
|
|
};
|
|
|
|
/*
|
|
* Returns readers from an a-priori prepared set of readers with determined lower and upper bounds
|
|
* on the positions of their fragments.
|
|
*/
|
|
struct simple_position_reader_queue : public position_reader_queue {
|
|
position_in_partition::tri_compare _cmp;
|
|
|
|
using container_t = std::vector<reader_bounds>;
|
|
container_t _rs;
|
|
container_t::iterator _it;
|
|
|
|
simple_position_reader_queue(const schema& s, std::vector<reader_bounds> rs)
|
|
// precondition: rs sorted w.r.t lower.
|
|
// `s` must be kept alive until the last call to `pop` or `empty`.
|
|
: _cmp(s), _rs(std::move(rs)), _it(_rs.begin())
|
|
{ }
|
|
|
|
virtual ~simple_position_reader_queue() override = default;
|
|
|
|
virtual std::vector<reader_and_upper_bound> pop(position_in_partition_view bound) override {
|
|
if (empty(bound)) {
|
|
return {};
|
|
}
|
|
|
|
// !empty(bound) implies that _it->lower <= bound.
|
|
|
|
std::vector<reader_and_upper_bound> ret;
|
|
auto it = _it;
|
|
for (; it != _rs.end() && _cmp(_it->lower, it->lower) == 0; ++it) {
|
|
ret.emplace_back(std::move(it->r), std::move(it->upper));
|
|
}
|
|
_it = it;
|
|
return ret;
|
|
}
|
|
|
|
virtual bool empty(position_in_partition_view bound) const override {
|
|
return _it == _rs.end() || _cmp(bound, _it->lower) < 0;
|
|
}
|
|
|
|
virtual future<> close() noexcept override {
|
|
return do_for_each(_it, _rs.end(), [] (reader_bounds& rb) {
|
|
auto r = std::move(rb.r);
|
|
return r.close();
|
|
}).finally([this] {
|
|
_it = _rs.end();
|
|
});
|
|
}
|
|
};
|