84 lines
2.2 KiB
C++
84 lines
2.2 KiB
C++
// Copyright (c) 2012-2013 The Cryptonote developers
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// Distributed under the MIT/X11 software license, see the accompanying
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// file COPYING or http://www.opensource.org/licenses/mit-license.php.
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#pragma once
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#include <atomic>
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#include "include_base_utils.h"
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namespace tools {
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class InitState {
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public:
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InitState() : m_state(STATE_NOT_INITIALIZED) {
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}
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bool initialized() const volatile {
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return STATE_INITIALIZED == m_state.load(std::memory_order_acquire);
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}
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bool beginInit() volatile {
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State state = STATE_NOT_INITIALIZED;
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if (!m_state.compare_exchange_strong(state, STATE_INITIALIZING, std::memory_order_seq_cst)) {
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LOG_ERROR("object has been already initialized");
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return false;
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}
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return true;
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}
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bool endInit() volatile {
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State expectedState = STATE_INITIALIZING;
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if (!m_state.compare_exchange_strong(expectedState, STATE_INITIALIZED, std::memory_order_seq_cst)) {
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LOG_ERROR("Unexpected state: " << expectedState);
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return false;
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}
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return true;
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}
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bool beginShutdown() volatile {
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while (true) {
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State state = m_state.load(std::memory_order_relaxed);
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if (STATE_NOT_INITIALIZED == state) {
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return true;
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} else if (STATE_INITIALIZING == state) {
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LOG_ERROR("Object is being initialized");
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return false;
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} else if (STATE_INITIALIZED == state) {
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if (m_state.compare_exchange_strong(state, STATE_SHUTTING_DOWN, std::memory_order_seq_cst)) {
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return true;
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}
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} else if (STATE_SHUTTING_DOWN == state) {
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LOG_ERROR("Object is being shutting down");
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return false;
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} else {
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LOG_ERROR("Unknown state " << state);
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return false;
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}
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}
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}
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bool endShutdown() volatile {
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State expectedState = STATE_SHUTTING_DOWN;
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if (!m_state.compare_exchange_strong(expectedState, STATE_NOT_INITIALIZED, std::memory_order_seq_cst)) {
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LOG_ERROR("Unexpected state: " << expectedState);
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return false;
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}
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return true;
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}
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private:
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enum State {
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STATE_NOT_INITIALIZED,
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STATE_INITIALIZING,
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STATE_INITIALIZED,
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STATE_SHUTTING_DOWN
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};
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private:
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std::atomic<State> m_state;
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};
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}
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