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/
90 lines
2.8 KiB
C++
90 lines
2.8 KiB
C++
/*
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* Copyright (C) 2021 ScyllaDB
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*/
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/*
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* SPDX-License-Identifier: LicenseRef-ScyllaDB-Source-Available-1.0
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*/
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#pragma once
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#include <seastar/core/format.hh>
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#include "mutation/mutation_fragment_v2.hh"
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/// Converts a stream of range_tombstone_change fragments to an equivalent stream of range_tombstone objects.
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/// The input fragments must be ordered by their position().
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/// The produced range_tombstone objects are non-overlapping and ordered by their position().
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///
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/// on_end_of_stream() must be called after consuming all fragments to produce the final fragment.
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///
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/// Example usage:
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///
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/// range_tombstone_assembler rta;
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/// if (auto rt_opt = rta.consume(range_tombstone_change(...))) {
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/// produce(*rt_opt);
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/// }
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/// if (auto rt_opt = rta.consume(range_tombstone_change(...))) {
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/// produce(*rt_opt);
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/// }
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/// if (auto rt_opt = rta.flush(position_in_partition(...)) {
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/// produce(*rt_opt);
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/// }
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/// rta.on_end_of_stream();
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///
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class range_tombstone_assembler {
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std::optional<range_tombstone_change> _prev_rt;
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private:
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bool has_active_tombstone() const {
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return _prev_rt && _prev_rt->tombstone();
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}
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public:
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tombstone get_current_tombstone() const {
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return _prev_rt ? _prev_rt->tombstone() : tombstone();
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}
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std::optional<range_tombstone_change> get_range_tombstone_change() && {
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return std::move(_prev_rt);
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}
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void reset() {
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_prev_rt = std::nullopt;
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}
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std::optional<range_tombstone> consume(const schema& s, range_tombstone_change&& rt) {
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std::optional<range_tombstone> rt_opt;
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auto less = position_in_partition::less_compare(s);
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if (has_active_tombstone() && less(_prev_rt->position(), rt.position())) {
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rt_opt = range_tombstone(_prev_rt->position(), rt.position(), _prev_rt->tombstone());
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}
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_prev_rt = std::move(rt);
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return rt_opt;
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}
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void on_end_of_stream() {
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if (has_active_tombstone()) {
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throw std::logic_error(format("Stream ends with an active range tombstone: {}", *_prev_rt));
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}
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}
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// Returns true if and only if flush() may return something.
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// Returns false if flush() won't return anything for sure.
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bool needs_flush() const {
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return has_active_tombstone();
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}
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std::optional<range_tombstone> flush(const schema& s, position_in_partition_view pos) {
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auto less = position_in_partition::less_compare(s);
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if (has_active_tombstone() && less(_prev_rt->position(), pos)) {
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position_in_partition start = _prev_rt->position();
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_prev_rt->set_position(position_in_partition(pos));
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return range_tombstone(std::move(start), pos, _prev_rt->tombstone());
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}
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return std::nullopt;
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}
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bool discardable() const {
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return !has_active_tombstone();
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}
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};
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