f5b05cf981
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
39 lines
863 B
C++
39 lines
863 B
C++
|
|
/*
|
|
* Copyright (C) 2015-present ScyllaDB
|
|
*/
|
|
|
|
/*
|
|
* SPDX-License-Identifier: AGPL-3.0-or-later
|
|
*/
|
|
|
|
#pragma once
|
|
|
|
#include <seastar/core/sstring.hh>
|
|
#include <seastar/core/print.hh>
|
|
#include <tuple>
|
|
|
|
namespace version {
|
|
class version {
|
|
std::tuple<uint16_t, uint16_t, uint16_t> _version;
|
|
public:
|
|
version(uint16_t x, uint16_t y = 0, uint16_t z = 0): _version(std::make_tuple(x, y, z)) {}
|
|
|
|
seastar::sstring to_sstring() {
|
|
return seastar::format("{:d}.{:d}.{:d}", std::get<0>(_version), std::get<1>(_version), std::get<2>(_version));
|
|
}
|
|
|
|
static version current() {
|
|
static version v(3, 0, 8);
|
|
return v;
|
|
}
|
|
|
|
std::strong_ordering operator<=>(const version&) const = default;
|
|
};
|
|
|
|
inline const seastar::sstring& release() {
|
|
static thread_local auto str_ver = version::current().to_sstring();
|
|
return str_ver;
|
|
}
|
|
}
|