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#include "browser_main_parts_qt.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/browser/child_process_security_policy.h"
#include "content/public/common/service_manager_connection.h"
#include "extensions/buildflags/buildflags.h"
#if BUILDFLAG(ENABLE_EXTENSIONS)
#include "extensions/common/constants.h"
#include "extensions/common/extensions_client.h"
#include "extensions/extensions_browser_client_qt.h"
#include "extensions/extension_system_factory_qt.h"
#include "common/extensions/extensions_client_qt.h"
#endif //BUILDFLAG(ENABLE_EXTENSIONS)
#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 <QCoreApplication>
#include <QEvent>
#include <QEventLoop>
#include <QObject>
#include <QTimerEvent>
#include <QtGui/qtgui-config.h>

#if QT_CONFIG(opengl)
#include "ui/gl/gl_context.h"
#include <QOpenGLContext>
#endif

#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 QObject,
                           public base::MessagePump
{
public:
    MessagePumpForUIQt()
        : m_delegate(nullptr)
        , m_explicitLoop(nullptr)
        , m_timerId(0)
    {
    }

    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
    {
        if (!m_delegate)
            m_delegate = base::MessageLoopForUI::current();
        QCoreApplication::postEvent(this, new QTimerEvent(0));
        m_timerScheduledTime = base::TimeTicks::Now();
    }

    void ScheduleDelayedWork(const base::TimeTicks &delayed_work_time) override
    {
        if (!m_delegate)
            m_delegate = base::MessageLoopForUI::current();
        if (delayed_work_time.is_null()) {
            killTimer(m_timerId);
            m_timerId = 0;
            m_timerScheduledTime = base::TimeTicks();
        } else if (!m_timerId || delayed_work_time < m_timerScheduledTime) {
            killTimer(m_timerId);
            m_timerId = startTimer(GetTimeIntervalMilliseconds(delayed_work_time));
            m_timerScheduledTime = delayed_work_time;
        }
    }

protected:
    void timerEvent(QTimerEvent *ev) override
    {
        Q_ASSERT(!ev->timerId() || m_timerId == ev->timerId());
        killTimer(m_timerId);
        m_timerId = 0;
        m_timerScheduledTime = base::TimeTicks();

        handleScheduledWork();
    }

private:
    // Both Qt and Chromium keep track of the current GL context by using
    // thread-local variables, and naturally they are completely unaware of each
    // other. As a result, when a QOpenGLContext is made current, the previous
    // gl::GLContext is not released, and vice-versa. This is fine as long as
    // each thread uses exclusively either Qt or Chromium GL bindings, which is
    // usually the case.
    //
    // The only exception is when the GL driver is considered thread-unsafe
    // (QOpenGLContext::supportsThreadedOpenGL() is false), in which case we
    // have to run all GL operations, including Chromium's GPU service, on the
    // UI thread. Now the bindings are being mixed and both Qt and Chromium get
    // quite confused regarding the current state of the surface.
    //
    // To get this to work we have to release the current QOpenGLContext before
    // executing any tasks from Chromium's GPU service and the gl::GLContext
    // afterwards. Since GPU service just posts tasks to the UI thread task
    // runner, we'll have to instrument the entire UI thread message pump.
    class ScopedGLContextChecker
    {
#if QT_CONFIG(opengl)
    public:
        ScopedGLContextChecker()
        {
            if (!m_enabled)
                return;

            if (QOpenGLContext *context = QOpenGLContext::currentContext())
                context->doneCurrent();
        }

        ~ScopedGLContextChecker()
        {
            if (!m_enabled)
                return;

            if (gl::GLContext *context = gl::GLContext::GetCurrent())
                context->ReleaseCurrent(nullptr);
        }

    private:
        bool m_enabled = !QOpenGLContext::supportsThreadedOpenGL();
#endif // QT_CONFIG(opengl)
    };


    void handleScheduledWork()
    {
        ScopedGLContextChecker glContextChecker;

        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;
    QEventLoop *m_explicitLoop;
    int m_timerId;
    base::TimeTicks m_timerScheduledTime;
};

}  // anonymous namespace

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

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

BrowserMainPartsQt::~BrowserMainPartsQt() = default;


int BrowserMainPartsQt::PreEarlyInitialization()
{
#if BUILDFLAG(ENABLE_EXTENSIONS)
    content::ChildProcessSecurityPolicy::GetInstance()->RegisterWebSafeScheme(extensions::kExtensionScheme);
#endif //ENABLE_EXTENSIONS
    base::MessageLoop::InitMessagePumpForUIFactory(messagePumpFactory);
    return 0;
}

void BrowserMainPartsQt::PreMainMessageLoopStart()
{
}

void BrowserMainPartsQt::PreMainMessageLoopRun()
{
#if BUILDFLAG(ENABLE_EXTENSIONS)
    extensions::ExtensionsClient::Set(new extensions::ExtensionsClientQt());
    extensions::ExtensionsBrowserClient::Set(new extensions::ExtensionsBrowserClientQt());
    extensions::ExtensionSystemFactoryQt::GetInstance();
#endif //ENABLE_EXTENSIONS
}

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"));
    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