Files
scylladb/utils/sequenced_set.hh
Nadav Har'El a7fa29bceb cross-tree: fix header file self-sufficiency
Scylla's coding standard requires that each header is self-sufficient,
i.e., it includes whatever other headers it needs - so it can be included
without having to include any other header before it.

We have a test for this, "ninja dev-headers", but it isn't run very
frequently, and it turns out our code deviated from this requirement
in a few places. This patch fixes those places, and after it
"ninja dev-headers" succeeds again.

Fixes #10995

Signed-off-by: Nadav Har'El <nyh@scylladb.com>

Closes #10997
2022-07-08 12:59:14 +03:00

76 lines
1.4 KiB
C++

/*
* Copyright (C) 2014-present ScyllaDB
*/
/*
* SPDX-License-Identifier: AGPL-3.0-or-later
*/
#pragma once
#include <vector>
#include <unordered_set>
#include <cstddef>
namespace utils {
/**
* This class implements an add-only vector that ensures that the elements are
* unique.
*
* This class provides a similar functionality to the Java's LinkedHashSet
* class.
*/
template<typename T>
struct sequenced_set {
typedef typename std::vector<T>::iterator iterator;
void push_back(const T& val) {
insert(val);
}
std::pair<iterator, bool> insert(const T& t) {
auto r = _set.insert(t);
if (r.second) {
try {
_vec.push_back(t);
return std::make_pair(std::prev(_vec.end()), true);
} catch (...) {
_set.erase(r.first);
throw;
}
}
return std::make_pair(_vec.end(), false);
}
size_t size() {
return _vec.size();
}
iterator begin() {
return _vec.begin();
}
iterator end() {
return _vec.end();
}
const std::vector<T>& get_vector() const {
return _vec;
}
std::vector<T>& get_vector() {
return _vec;
}
void reserve(size_t sz) {
_set.reserve(sz);
_vec.reserve(sz);
}
private:
std::unordered_set<T> _set;
std::vector<T> _vec;
};
} // namespace utils