Files
scylladb/cql3/selection/simple_selector.hh
Avi Kivity fcb8d040e8 treewide: use Software Package Data Exchange (SPDX) license identifiers
Instead of lengthy blurbs, switch to single-line, machine-readable
standardized (https://spdx.dev) license identifiers. The Linux kernel
switched long ago, so there is strong precedent.

Three cases are handled: AGPL-only, Apache-only, and dual licensed.
For the latter case, I chose (AGPL-3.0-or-later and Apache-2.0),
reasoning that our changes are extensive enough to apply our license.

The changes we applied mechanically with a script, except to
licenses/README.md.

Closes #9937
2022-01-18 12:15:18 +01:00

105 lines
2.4 KiB
C++

/*
*/
/*
* Copyright (C) 2015-present ScyllaDB
*
* Modified by ScyllaDB
*/
/*
* SPDX-License-Identifier: (AGPL-3.0-or-later and Apache-2.0)
*/
#pragma once
#include "cql3/selection/selection.hh"
#include "cql3/selection/selector.hh"
namespace cql3 {
namespace selection {
class simple_selector_factory : public selector::factory {
private:
const sstring _column_name;
const uint32_t _idx;
data_type _type;
public:
simple_selector_factory(const sstring& column_name, uint32_t idx, data_type type)
: _column_name(std::move(column_name))
, _idx(idx)
, _type(type)
{ }
virtual sstring column_name() const override {
return _column_name;
}
virtual data_type get_return_type() const override {
return _type;
}
virtual ::shared_ptr<selector> new_instance() const override;
};
class simple_selector : public selector {
private:
const sstring _column_name;
const uint32_t _idx;
data_type _type;
bytes_opt _current;
bool _first; ///< Whether the next row we receive is the first in its group.
public:
static ::shared_ptr<factory> new_factory(const sstring& column_name, uint32_t idx, data_type type) {
return ::make_shared<simple_selector_factory>(column_name, idx, type);
}
simple_selector(const sstring& column_name, uint32_t idx, data_type type)
: _column_name(std::move(column_name))
, _idx(idx)
, _type(type)
, _first(true)
{ }
virtual void add_input(cql_serialization_format sf, result_set_builder& rs) override {
// GROUP BY calls add_input() repeatedly without reset() in between, and it expects the
// output to be the first value encountered:
// https://cassandra.apache.org/doc/latest/cql/dml.html#grouping-results
if (_first) {
// TODO: can we steal it?
_current = (*rs.current)[_idx];
_first = false;
}
}
virtual bytes_opt get_output(cql_serialization_format sf) override {
return std::move(_current);
}
virtual void reset() override {
_current = {};
_first = true;
}
virtual data_type get_type() const override {
return _type;
}
virtual sstring assignment_testable_source_context() const override {
return _column_name;
}
#if 0
@Override
public String toString()
{
return columnName;
}
#endif
};
}
}