1d84a254c0
The flat_mutation_reader files were conflated and contained multiple readers, which were not strictly necessary. Splitting optimizes both iterative compilation times, as touching rarely used readers doesn't recompile large chunks of codebase. Total compilation times are also improved, as the size of flat_mutation_reader.hh and flat_mutation_reader_v2.hh have been reduced and those files are included by many file in the codebase. With changes real 29m14.051s user 168m39.071s sys 5m13.443s Without changes real 30m36.203s user 175m43.354s sys 5m26.376s Closes #10194
101 lines
3.2 KiB
C++
101 lines
3.2 KiB
C++
/*
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* Copyright 2020-present ScyllaDB
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*/
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/*
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* SPDX-License-Identifier: AGPL-3.0-or-later
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*/
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#pragma once
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#include <seastar/core/shared_future.hh>
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#include "readers/flat_mutation_reader_v2.hh"
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// A reader which allows to insert a deferring operation before reading.
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// All calls will first wait for a future to resolve, then forward to a given underlying reader.
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class chained_delegating_reader : public flat_mutation_reader_v2::impl {
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std::unique_ptr<flat_mutation_reader_v2> _underlying;
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std::function<future<flat_mutation_reader_v2>()> _populate_reader;
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std::function<void()> _on_destroyed;
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public:
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chained_delegating_reader(schema_ptr s, std::function<future<flat_mutation_reader_v2>()>&& populate, reader_permit permit, std::function<void()> on_destroyed = []{})
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: impl(s, std::move(permit))
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, _populate_reader(std::move(populate))
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, _on_destroyed(std::move(on_destroyed))
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{ }
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chained_delegating_reader(chained_delegating_reader&& rd) = delete;
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~chained_delegating_reader() {
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_on_destroyed();
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}
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virtual future<> fill_buffer() override {
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if (!_underlying) {
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return _populate_reader().then([this] (flat_mutation_reader_v2&& rd) {
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_underlying = std::make_unique<flat_mutation_reader_v2>(std::move(rd));
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return fill_buffer();
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});
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}
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if (is_buffer_full()) {
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return make_ready_future<>();
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}
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return _underlying->fill_buffer().then([this] {
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_end_of_stream = _underlying->is_end_of_stream();
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_underlying->move_buffer_content_to(*this);
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});
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}
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virtual future<> fast_forward_to(position_range pr) override {
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if (!_underlying) {
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return _populate_reader().then([this, pr = std::move(pr)] (flat_mutation_reader_v2&& rd) mutable {
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_underlying = std::make_unique<flat_mutation_reader_v2>(std::move(rd));
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return fast_forward_to(pr);
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});
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}
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_end_of_stream = false;
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forward_buffer_to(pr.start());
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return _underlying->fast_forward_to(std::move(pr));
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}
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virtual future<> next_partition() override {
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if (!_underlying) {
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return make_ready_future<>();
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}
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clear_buffer_to_next_partition();
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auto f = make_ready_future<>();
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if (is_buffer_empty()) {
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f = _underlying->next_partition();
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}
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_end_of_stream = _underlying->is_end_of_stream() && _underlying->is_buffer_empty();
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return f;
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}
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virtual future<> fast_forward_to(const dht::partition_range& pr) override {
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if (!_underlying) {
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return _populate_reader().then([this, &pr] (flat_mutation_reader_v2&& rd) mutable {
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_underlying = std::make_unique<flat_mutation_reader_v2>(std::move(rd));
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return fast_forward_to(pr);
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});
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}
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_end_of_stream = false;
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clear_buffer();
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return _underlying->fast_forward_to(pr);
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}
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virtual future<> close() noexcept override {
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if (_underlying) {
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return _underlying->close();
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}
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return make_ready_future<>();
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}
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};
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