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// Copyright (C) 2020 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GPL-3.0-only WITH Qt-GPL-exception-1.0
#ifndef SYNCHRONIZED_H
#define SYNCHRONIZED_H
#include <QtCore/qmutex.h>
#include <atomic>
#include <vector>
QT_BEGIN_NAMESPACE
template<typename T> class WriteSynchronizedRef
{
Q_DISABLE_COPY_MOVE(WriteSynchronizedRef)
public:
WriteSynchronizedRef(std::vector<T> &vector) Q_DECL_NOEXCEPT
: m_vector(vector)
{}
void emplace_back(T &&value)
{
QMutexLocker lock(&m_mutex);
m_vector.push_back(std::move(value));
}
void emplace_back(const T &value)
{
QMutexLocker lock(&m_mutex);
m_vector.emplace_back(value);
}
void emplace_bulk(std::vector<T> && values)
{
QMutexLocker lock(&m_mutex);
if (!m_vector.empty()) {
m_vector.insert(m_vector.cend(), std::make_move_iterator(values.begin()),
std::make_move_iterator(values.end()));
} else {
m_vector = std::move(values);
}
}
private:
mutable QMutex m_mutex;
std::vector<T> &m_vector;
};
template<typename T> class ReadSynchronizedRef
{
Q_DISABLE_COPY_MOVE(ReadSynchronizedRef)
public:
ReadSynchronizedRef(const std::vector<T> &v) noexcept
: m_vector(v)
{}
size_t size() const
{
return m_vector.size();
}
bool next(T *value) const
{
const auto idx = m_next.fetch_add(1, std::memory_order_acquire);
const bool hasNext = idx < m_vector.size();
if (hasNext)
*value = m_vector[idx];
return hasNext;
}
private:
const std::vector<T> &m_vector;
mutable std::atomic<size_t> m_next = 0;
};
QT_END_NAMESPACE
#endif