44 lines
1.8 KiB
C++
44 lines
1.8 KiB
C++
// Copyright 2023 Dolphin Emulator Project
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// SPDX-License-Identifier: GPL-2.0-or-later
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#pragma once
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#include <atomic>
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#include "Common/CommonTypes.h"
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class TASControlState
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{
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public:
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// Call this from the CPU thread to get the current value. (This function can also safely be
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// called from the UI thread, but you're effectively just getting the value the UI control has.)
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int GetValue() const;
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// Call this from the CPU thread when the controller state changes.
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// If the return value is true, queue up a call to ApplyControllerChangeValue on the UI thread.
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bool OnControllerValueChanged(int new_value);
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// Call this from the UI thread when the user changes the value using the UI.
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void OnUIValueChanged(int new_value);
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// Call this from the UI thread after OnControllerValueChanged returns true,
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// and set the state of the UI control to the return value.
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int ApplyControllerValueChange();
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private:
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// A description of how threading is handled: The UI thread can update its copy of the state
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// whenever it wants to, and must *not* increment the version when doing so. The CPU thread can
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// update its copy of the state whenever it wants to, and *must* increment the version when doing
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// so. When the CPU thread updates its copy of the state, the UI thread should then (possibly
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// after a delay) mirror the change by copying the CPU thread's state to the UI thread's state.
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// This mirroring is the only way for the version number stored in the UI thread's state to
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// change. The version numbers of the two copies can be compared to check if the UI thread's view
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// of what has happened on the CPU thread is up to date.
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struct State
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{
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int version = 0;
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int value = 0;
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};
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std::atomic<State> m_ui_thread_state;
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std::atomic<State> m_cpu_thread_state;
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};
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