AuroraRuntime/Source/IO/Loop/LSFromFdNonblocking.hpp

/***
    Copyright (C) 2022 J Reece Wilson (a/k/a "Reece"). All rights reserved.

    File: LSFromFdNonblocking.cpp
    Date: 2022-4-5
    Author: Reece
***/
#pragma once

#if defined(AURORA_IS_LINUX_DERIVED)

namespace Aurora::IO::UNIX
{
    bool LinuxOverlappedYield(bool bUserspaceOnly);
}

#endif

namespace Aurora::IO::Loop
{
    template<typename T>
    inline bool IsSignaledFromNonblockingImpl(ILoopSourceEx *source, T * that, bool(T::*IsSignaledNonblocking)(), bool bIOTick)
    {
        bool val {};
        source->OnPresleep();
        val = ((that)->*(IsSignaledNonblocking))();
        source->OnFinishSleep();
        // Required for precise Windows on Linux OVERLAPPED semantics for emulators.
        // IAsyncTransaction::Complete()/Wait() will always enter an alertable state and dispatch io completion callbacks.
        // In theory, we don't need this.
        // In practice, if NT can atomically set an event and update the apc queue, we could be out of parity.
        if (bIOTick)
        {
        #if defined(AURORA_IS_LINUX_DERIVED)
            // Do not syscall after read or select again under Linux
            UNIX::LinuxOverlappedYield(true);
        #else
            IOYield();
        #endif
        }
        return val;
    }
}