global_state.hpp

// Copyright (c) Microsoft Corporation.
// Licensed under the MIT License.
 
#pragma once
 
#include <azure/core/azure_assert.hpp>
 
#include <atomic>
#include <list>
#include <memory>
#include <mutex>
#include <thread>
 
namespace Azure { namespace Core { namespace Amqp { namespace Common { namespace _detail {
 
  class Pollable {
  public:
    Pollable() = default;
    Pollable(const Pollable&) = delete;
    Pollable& operator=(const Pollable&) = delete;
    Pollable(Pollable&&) = delete;
    Pollable& operator=(Pollable&&) = delete;
 
    virtual void Poll() = 0;
    virtual ~Pollable() = default;
  };
  class GlobalStateHolder final {
    GlobalStateHolder();
    ~GlobalStateHolder();
 
    std::list<std::shared_ptr<Pollable>> m_pollables;
    std::mutex m_pollablesMutex;
    std::thread m_pollingThread;
    std::atomic<bool> m_activelyPolling;
    bool m_stopped{false};
 
  public:
    static GlobalStateHolder* GlobalStateInstance();
 
    GlobalStateHolder(GlobalStateHolder const&) = delete;
    GlobalStateHolder& operator=(GlobalStateHolder const&) = delete;
 
    GlobalStateHolder(GlobalStateHolder&&) = delete;
    GlobalStateHolder& operator=(GlobalStateHolder&&) = delete;
 
    void AddPollable(std::shared_ptr<Pollable> pollable);
 
    void RemovePollable(std::shared_ptr<Pollable> pollable);
 
    void AssertIdle()
    {
      std::lock_guard<std::mutex> lock(m_pollablesMutex);
      AZURE_ASSERT(m_pollables.empty());
      if (!m_pollables.empty())
      {
        Azure::Core::_internal::AzureNoReturnPath("Global state is not idle.");
      }
    }
  };
}}}}} // namespace Azure::Core::Amqp::Common::_detail