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#include "browser_main_parts_qt.h"

#include "api/qwebenginemessagepumpscheduler_p.h"

#include "base/message_loop/message_loop.h"
#include "base/process/process.h"
#include "base/threading/thread_restrictions.h"
#include "content/public/browser/browser_main_parts.h"
#include "content/public/browser/browser_thread.h"
#include "content/public/common/service_manager_connection.h"
#include "services/resource_coordinator/public/cpp/process_resource_coordinator.h"
#include "services/resource_coordinator/public/cpp/resource_coordinator_features.h"
#include "services/service_manager/public/cpp/connector.h"
#include "services/service_manager/public/cpp/service.h"
#include "ui/display/screen.h"

#include "service/service_qt.h"
#include "web_engine_context.h"

#include <QEventLoop>

#if defined(OS_MACOSX)
#include "ui/base/idle/idle.h"
#endif

#if defined(Q_OS_WIN)
#include "ui/display/win/screen_win.h"
#else
#include "desktop_screen_qt.h"
#endif


namespace QtWebEngineCore {

namespace {

// Return a timeout suitable for the glib loop, -1 to block forever,
// 0 to return right away, or a timeout in milliseconds from now.
int GetTimeIntervalMilliseconds(const base::TimeTicks &from)
{
    if (from.is_null())
        return -1;

    // Be careful here.  TimeDelta has a precision of microseconds, but we want a
    // value in milliseconds.  If there are 5.5ms left, should the delay be 5 or
    // 6?  It should be 6 to avoid executing delayed work too early.
    int delay = static_cast<int>(std::ceil((from - base::TimeTicks::Now()).InMillisecondsF()));

    // If this value is negative, then we need to run delayed work soon.
    return delay < 0 ? 0 : delay;
}

class MessagePumpForUIQt : public base::MessagePump
{
public:
    MessagePumpForUIQt()
        : m_scheduler([this]() { handleScheduledWork(); })
    {}

    void Run(Delegate *delegate) override
    {
        if (!m_delegate)
            m_delegate = delegate;
        else
            Q_ASSERT(delegate == m_delegate);
        // This is used only when MessagePumpForUIQt is used outside of the GUI thread.
        QEventLoop loop;
        m_explicitLoop = &loop;
        loop.exec();
        m_explicitLoop = nullptr;
    }

    void Quit() override
    {
        Q_ASSERT(m_explicitLoop);
        m_explicitLoop->quit();
    }

    void ScheduleWork() override
    {
        // NOTE: This method may called from any thread at any time.
        if (!m_delegate)
            m_delegate = base::MessageLoopForUI::current();
        m_scheduler.scheduleWork();
    }

    void ScheduleDelayedWork(const base::TimeTicks &delayed_work_time) override
    {
        if (!m_delegate)
            m_delegate = base::MessageLoopForUI::current();
        m_scheduler.scheduleDelayedWork(GetTimeIntervalMilliseconds(delayed_work_time));
    }

private:
    void handleScheduledWork()
    {
        bool more_work_is_plausible = m_delegate->DoWork();

        base::TimeTicks delayed_work_time;
        more_work_is_plausible |= m_delegate->DoDelayedWork(&delayed_work_time);

        if (more_work_is_plausible)
            return ScheduleWork();

        more_work_is_plausible |= m_delegate->DoIdleWork();
        if (more_work_is_plausible)
            return ScheduleWork();

        ScheduleDelayedWork(delayed_work_time);
    }

    Delegate *m_delegate = nullptr;
    QEventLoop *m_explicitLoop = nullptr;
    QWebEngineMessagePumpScheduler m_scheduler;
};

}  // anonymous namespace

std::unique_ptr<base::MessagePump> messagePumpFactory()
{
    return base::WrapUnique(new MessagePumpForUIQt);
}

BrowserMainPartsQt::BrowserMainPartsQt() : content::BrowserMainParts()
{ }

BrowserMainPartsQt::~BrowserMainPartsQt() = default;


int BrowserMainPartsQt::PreEarlyInitialization()
{
    base::MessageLoop::InitMessagePumpForUIFactory(messagePumpFactory);
    return 0;
}

void BrowserMainPartsQt::PreMainMessageLoopStart()
{
}

void BrowserMainPartsQt::PostMainMessageLoopRun()
{
    // The ProfileQt's destructor uses the MessageLoop so it should be deleted
    // right before the RenderProcessHostImpl's destructor destroys it.
    WebEngineContext::current()->destroyProfileAdapter();
}

int BrowserMainPartsQt::PreCreateThreads()
{
    base::ThreadRestrictions::SetIOAllowed(true);

#if defined(OS_MACOSX)
    ui::InitIdleMonitor();
#endif

    // Like ChromeBrowserMainExtraPartsViews::PreCreateThreads does.
#if defined(Q_OS_WIN)
    display::Screen::SetScreenInstance(new display::win::ScreenWin);
#else
    display::Screen::SetScreenInstance(new DesktopScreenQt);
#endif
    return 0;
}

void BrowserMainPartsQt::ServiceManagerConnectionStarted(content::ServiceManagerConnection *connection)
{
    ServiceQt::GetInstance()->InitConnector();
    connection->GetConnector()->StartService(service_manager::Identity("qtwebengine"));
    if (resource_coordinator::IsResourceCoordinatorEnabled()) {
        m_processResourceCoordinator = std::make_unique<resource_coordinator::ProcessResourceCoordinator>(connection->GetConnector());
        m_processResourceCoordinator->SetLaunchTime(base::Time::Now());
        m_processResourceCoordinator->SetPID(base::Process::Current().Pid());
    }
}

} // namespace QtWebEngineCore