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/*
*
*/
#pragma once
#include <deque>
#include <atomic>
#include <cassert>
namespace de {
class LockManager {
public:
LockManager(size_t levels=1) {
for (size_t i=0; i < levels; i++) {
m_lks.emplace_back(false);
}
m_last_unlocked_version = 0;
}
~LockManager() = default;
void add_lock() {
m_lks.emplace_back(false);
}
void release_lock(size_t idx, size_t version) {
if (idx < m_lks.size()) {
assert(m_lks.at(idx).load() == true);
m_lks.at(idx).store(false);
while (m_last_unlocked_version.load() < version) {
auto tmp = m_last_unlocked_version.load();
m_last_unlocked_version.compare_exchange_strong(tmp, version);
}
}
}
bool is_locked(size_t idx, size_t version) {
if (idx < m_lks.size()) {
return m_lks.at(idx).load() && m_last_unlocked_version <= version;
}
return false;
}
bool take_lock(size_t idx, size_t version) {
if (idx < m_lks.size()) {
bool old = m_lks.at(idx).load();
if (!old) {
auto result = m_lks.at(idx).compare_exchange_strong(old, true);
if (m_last_unlocked_version.load() > version) {
m_lks.at(idx).store(false);
return false;
}
return result;
}
}
return false;
}
bool take_buffer_lock() {
bool old = m_buffer_lk.load();
if (!old) {
return m_buffer_lk.compare_exchange_strong(old, true);
}
return false;
}
bool is_buffer_locked() {
return m_buffer_lk.load();
}
void release_buffer_lock() {
m_buffer_lk.store(false);
}
private:
std::deque<std::atomic<bool>> m_lks;
std::atomic<bool> m_buffer_lk;
std::atomic<size_t> m_last_unlocked_version;
};
}
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