danicoin/src/node_rpc_proxy/InitState.h
2014-08-13 11:38:35 +01:00

97 lines
2.7 KiB
C++

// Copyright (c) 2012-2014, The CryptoNote developers, The Bytecoin developers
//
// This file is part of Bytecoin.
//
// Bytecoin is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// Bytecoin is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with Bytecoin. If not, see <http://www.gnu.org/licenses/>.
#pragma once
#include <atomic>
#include "include_base_utils.h"
namespace tools {
class InitState {
public:
InitState() : m_state(STATE_NOT_INITIALIZED) {
}
bool initialized() const volatile {
return STATE_INITIALIZED == m_state.load(std::memory_order_acquire);
}
bool beginInit() volatile {
State state = STATE_NOT_INITIALIZED;
if (!m_state.compare_exchange_strong(state, STATE_INITIALIZING, std::memory_order_seq_cst)) {
LOG_ERROR("object has been already initialized");
return false;
}
return true;
}
bool endInit() volatile {
State expectedState = STATE_INITIALIZING;
if (!m_state.compare_exchange_strong(expectedState, STATE_INITIALIZED, std::memory_order_seq_cst)) {
LOG_ERROR("Unexpected state: " << expectedState);
return false;
}
return true;
}
bool beginShutdown() volatile {
while (true) {
State state = m_state.load(std::memory_order_relaxed);
if (STATE_NOT_INITIALIZED == state) {
return true;
} else if (STATE_INITIALIZING == state) {
LOG_ERROR("Object is being initialized");
return false;
} else if (STATE_INITIALIZED == state) {
if (m_state.compare_exchange_strong(state, STATE_SHUTTING_DOWN, std::memory_order_seq_cst)) {
return true;
}
} else if (STATE_SHUTTING_DOWN == state) {
LOG_ERROR("Object is being shutting down");
return false;
} else {
LOG_ERROR("Unknown state " << state);
return false;
}
}
}
bool endShutdown() volatile {
State expectedState = STATE_SHUTTING_DOWN;
if (!m_state.compare_exchange_strong(expectedState, STATE_NOT_INITIALIZED, std::memory_order_seq_cst)) {
LOG_ERROR("Unexpected state: " << expectedState);
return false;
}
return true;
}
private:
enum State {
STATE_NOT_INITIALIZED,
STATE_INITIALIZING,
STATE_INITIALIZED,
STATE_SHUTTING_DOWN
};
private:
std::atomic<State> m_state;
};
}