dolphin/Source/Android/jni/Host.h

// Copyright 2023 Dolphin Emulator Project
// SPDX-License-Identifier: GPL-2.0-or-later

#pragma once

#include <mutex>

#include "Core/Core.h"

// The Core only supports using a single Host thread.
// If multiple threads want to call host functions then they need to queue
// sequentially for access.
struct HostThreadLock
{
public:
  explicit HostThreadLock() : m_lock(s_host_identity_mutex) { Core::DeclareAsHostThread(); }

  ~HostThreadLock()
  {
    if (m_lock.owns_lock())
      Core::UndeclareAsHostThread();
  }

  HostThreadLock(const HostThreadLock& other) = delete;
  HostThreadLock(HostThreadLock&& other) = delete;
  HostThreadLock& operator=(const HostThreadLock& other) = delete;
  HostThreadLock& operator=(HostThreadLock&& other) = delete;

  void Lock()
  {
    m_lock.lock();
    Core::DeclareAsHostThread();
  }

  void Unlock()
  {
    m_lock.unlock();
    Core::UndeclareAsHostThread();
  }

private:
  static std::mutex s_host_identity_mutex;
  std::unique_lock<std::mutex> m_lock;
};