in C++20, compiler generate operator!=() if the corresponding operator==() is already defined, the language now understands that the comparison is symmetric in the new standard. fortunately, our operator!=() is always equivalent to `! operator==()`, this matches the behavior of the default generated operator!=(). so, in this change, all `operator!=` are removed. in addition to the defaulted operator!=, C++20 also brings to us the defaulted operator==() -- it is able to generated the operator==() if the member-wise lexicographical comparison. under some circumstances, this is exactly what we need. so, in this change, if the operator==() is also implemented as a lexicographical comparison of all memeber variables of the class/struct in question, it is implemented using the default generated one by removing its body and mark the function as `default`. moreover, if the class happen to have other comparison operators which are implemented using lexicographical comparison, the default generated `operator<=>` is used in place of the defaulted `operator==`. sometimes, we fail to mark the operator== with the `const` specifier, in this change, to fulfil the need of C++ standard, and to be more correct, the `const` specifier is added. also, to generate the defaulted operator==, the operand should be `const class_name&`, but it is not always the case, in the class of `version`, we use `version` as the parameter type, to fulfill the need of the C++ standard, the parameter type is changed to `const version&` instead. this does not change the semantic of the comparison operator. and is a more idiomatic way to pass non-trivial struct as function parameters. please note, because in C++20, both operator= and operator<=> are symmetric, some of the operators in `multiprecision` are removed. they are the symmetric form of the another variant. if they were not removed, compiler would, for instance, find ambiguous overloaded operator '=='. this change is a cleanup to modernize the code base with C++20 features. Signed-off-by: Kefu Chai <kefu.chai@scylladb.com> Closes #13687
34 lines
1016 B
C++
34 lines
1016 B
C++
/*
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* Copyright (C) 2021-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 <map>
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#include <chrono>
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#include <seastar/core/sstring.hh>
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enum class tombstone_gc_mode : uint8_t { timeout, disabled, immediate, repair };
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class tombstone_gc_options {
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private:
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tombstone_gc_mode _mode = tombstone_gc_mode::timeout;
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std::chrono::seconds _propagation_delay_in_seconds = std::chrono::seconds(3600);
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public:
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tombstone_gc_options() = default;
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const tombstone_gc_mode& mode() const { return _mode; }
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explicit tombstone_gc_options(const std::map<seastar::sstring, seastar::sstring>& map);
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const std::chrono::seconds& propagation_delay_in_seconds() const {
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return _propagation_delay_in_seconds;
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}
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std::map<seastar::sstring, seastar::sstring> to_map() const;
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seastar::sstring to_sstring() const;
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bool operator==(const tombstone_gc_options&) const = default;
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};
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std::ostream& operator<<(std::ostream& os, const tombstone_gc_mode& m);
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