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6b63417bc8
Because `selection` is not serializable and it has to be send via network to parallelize query, we have to mock the selection. To simplify the mocking, for now only single selectors for aggregate's arguments are allowed (no casting or other functions as arguments).
106 lines
2.5 KiB
C++
106 lines
2.5 KiB
C++
/*
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* Copyright (C) 2015-present ScyllaDB
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*
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* Modified by ScyllaDB
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*/
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/*
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* SPDX-License-Identifier: (AGPL-3.0-or-later and Apache-2.0)
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*/
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#pragma once
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#include "cql3/selection/selection.hh"
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#include "cql3/selection/selector.hh"
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namespace cql3 {
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namespace selection {
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class simple_selector_factory : public selector::factory {
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private:
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const sstring _column_name;
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const uint32_t _idx;
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data_type _type;
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public:
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simple_selector_factory(const sstring& column_name, uint32_t idx, data_type type)
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: _column_name(std::move(column_name))
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, _idx(idx)
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, _type(type)
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{ }
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virtual bool is_simple_selector_factory() const override {
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return true;
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}
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virtual sstring column_name() const override {
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return _column_name;
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}
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virtual data_type get_return_type() const override {
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return _type;
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}
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virtual ::shared_ptr<selector> new_instance() const override;
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};
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class simple_selector : public selector {
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private:
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const sstring _column_name;
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const uint32_t _idx;
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data_type _type;
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bytes_opt _current;
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bool _first; ///< Whether the next row we receive is the first in its group.
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public:
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static ::shared_ptr<factory> new_factory(const sstring& column_name, uint32_t idx, data_type type) {
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return ::make_shared<simple_selector_factory>(column_name, idx, type);
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}
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simple_selector(const sstring& column_name, uint32_t idx, data_type type)
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: _column_name(std::move(column_name))
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, _idx(idx)
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, _type(type)
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, _first(true)
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{ }
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virtual void add_input(cql_serialization_format sf, result_set_builder& rs) override {
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// GROUP BY calls add_input() repeatedly without reset() in between, and it expects the
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// output to be the first value encountered:
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// https://cassandra.apache.org/doc/latest/cql/dml.html#grouping-results
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if (_first) {
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// TODO: can we steal it?
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_current = (*rs.current)[_idx];
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_first = false;
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}
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}
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virtual bytes_opt get_output(cql_serialization_format sf) override {
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return std::move(_current);
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}
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virtual void reset() override {
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_current = {};
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_first = true;
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}
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virtual data_type get_type() const override {
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return _type;
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}
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virtual sstring assignment_testable_source_context() const override {
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return _column_name;
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}
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#if 0
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@Override
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public String toString()
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{
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return columnName;
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}
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#endif
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};
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}
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}
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