corocontext.cpp

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/**********************************************************************
 * LeechCraft - modular cross-platform feature rich internet client.
 * Copyright (C) 2006-2014  Georg Rudoy
 *
 * Distributed under the Boost Software License, Version 1.0.
 * (See accompanying file LICENSE or copy at https://www.boost.org/LICENSE_1_0.txt)
 **********************************************************************/
 
#include "corocontext.h"
#include <unordered_map>
#include <QThread>
#include <QtDebug>
#include "context.h"
#include "task.h"
 
namespace LC::Util
{
    ContextDeadException::ContextDeadException (const QString& name)
    : std::runtime_error { "coroutine's context " + name.toStdString () + " died" }
    {
    }
 
    CoroContext::CoroContext (const QString& name)
    : Name_ { name }
    {
    }
 
    CoroContext::CoroContext (const QObject& obj)
    : CoroContext { obj.objectName ().isEmpty () ? obj.metaObject ()->className () : obj.objectName () }
    {
    }
 
    CoroContext::~CoroContext ()
    {
        for (const auto [_, base, _] : Coros_)
            if (base->State_ == detail::PromiseBase::CoroState::Running)
                qFatal () << "destroying the context" << Name_ << "while its child coro is running; "
                        << "defer the destruction with `QObject::deleteLater()` or a timer";
 
        while (!Coros_.empty ())
        {
            const auto [handle, base, promise] = Coros_.front ();
            Coros_.pop_front ();
 
            std::erase_if (promise->Contexts_, [this] (const Registration& reg) { return reg.Ctx_ == this; });
            promise->DeadContexts_ << Name_;
 
            if (!handle.done ())
                handle.resume ();
        }
    }
 
    CoroContext& CoroContext::Of (QObject& obj)
    {
        if (obj.thread () != QThread::currentThread ())
        {
            using namespace std::string_literals;
            const auto& msg = "binding to a QObject "s + obj.metaObject ()->className () +
                    " [" + obj.objectName ().toStdString () + "] from a different thread";
            throw std::runtime_error { msg };
        }
 
        thread_local std::unordered_map<QObject*, std::unique_ptr<CoroContext>> contexts;
        auto& ctx = contexts [&obj];
        if (!ctx)
        {
            ctx = std::make_unique<CoroContext> (obj);
            QObject::connect (&obj,
                    &QObject::destroyed,
                    [&obj]
                    {
                        if (!contexts.erase (&obj))
                            qCritical () << "could not find" << &obj << "in the contexts map — threading messed up?";
                    });
        }
        return *ctx;
    }
}