54 lines
1.1 KiB
C
54 lines
1.1 KiB
C
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// Copyright 2022, Roman Gershman. All rights reserved.
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// See LICENSE for licensing terms.
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//
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#pragma once
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#include <atomic>
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#include <utility>
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namespace dfly {
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// Switches from IDLE state to any of the non-idle states.
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// Switched from non-idle to IDLE.
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// Refuses switching from non-idle to another non-idle state directly.
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//
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class GlobalState {
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public:
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enum S : uint8_t {
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IDLE,
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LOADING,
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SAVING,
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SHUTTING_DOWN,
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};
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GlobalState(S s = IDLE) : s_(s) {
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}
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const char* Name() const {
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return Name(s_.load(std::memory_order_relaxed));
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}
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static const char* Name(S s);
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std::pair<S, bool> Next(S s) {
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S current{IDLE};
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bool res = s_.compare_exchange_strong(current, s, std::memory_order_acq_rel);
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return std::make_pair(current, res);
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}
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// Switches to IDLE and returns the previous state.
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S Clear() {
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return s_.exchange(IDLE, std::memory_order_acq_rel);
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}
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// Returns the current state.
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S Load() const {
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return s_.load(std::memory_order_acq_rel);
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}
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private:
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std::atomic<S> s_;
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};
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} // namespace dfly
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