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/
75 lines
2.7 KiB
C++
75 lines
2.7 KiB
C++
/*
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* Copyright (C) 2022-present 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 "readers/mutation_reader.hh"
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template <typename MutationFilter>
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requires std::is_invocable_r_v<bool, MutationFilter, const dht::decorated_key&>
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class filtering_reader : public mutation_reader::impl {
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mutation_reader _rd;
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MutationFilter _filter;
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public:
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filtering_reader(mutation_reader rd, MutationFilter&& filter)
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: impl(rd.schema(), rd.permit())
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, _rd(std::move(rd))
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, _filter(std::forward<MutationFilter>(filter)) {
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}
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virtual future<> fill_buffer() override {
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return do_until([this] { return is_buffer_full() || is_end_of_stream(); }, [this] {
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return _rd.fill_buffer().then([this] {
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return do_until([this] { return _rd.is_buffer_empty(); }, [this] {
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auto mf = _rd.pop_mutation_fragment();
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if (mf.is_partition_start()) {
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auto& dk = mf.as_partition_start().key();
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if (!_filter(dk)) {
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return _rd.next_partition();
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}
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}
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push_mutation_fragment(std::move(mf));
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return make_ready_future<>();
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}).then([this] {
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_end_of_stream = _rd.is_end_of_stream();
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});
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});
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});
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}
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virtual future<> next_partition() override {
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clear_buffer_to_next_partition();
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if (is_buffer_empty()) {
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_end_of_stream = false;
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return _rd.next_partition();
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}
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return make_ready_future<>();
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}
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virtual future<> fast_forward_to(const dht::partition_range& pr) override {
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clear_buffer();
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_end_of_stream = false;
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return _rd.fast_forward_to(pr);
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}
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virtual future<> fast_forward_to(position_range pr) override {
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clear_buffer();
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_end_of_stream = false;
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return _rd.fast_forward_to(std::move(pr));
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}
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virtual future<> close() noexcept override {
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return _rd.close();
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}
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};
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// Creates a mutation_reader wrapper which creates a new stream of mutations
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// with some mutations removed from the original stream.
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// MutationFilter is a callable which decides which mutations are dropped. It
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// accepts mutation const& and returns a bool. The mutation stays in the
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// stream if and only if the filter returns true.
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template <typename MutationFilter>
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mutation_reader make_filtering_reader(mutation_reader rd, MutationFilter&& filter) {
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return make_mutation_reader<filtering_reader<MutationFilter>>(std::move(rd), std::forward<MutationFilter>(filter));
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}
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