在执行C++ main()之前处理Mac OS X文件打开事件

Question

我已经google了很多,但仍然找不到好的解决方案:/
所以,我将一个复杂的Qt5应用程序(某些网络服务的客户端)移植到Mac OS X(10.7.0"Lion"及更高版本).

我需要处理自定义文件*.xyz和自定义URL方案xyz://.
好的,Qt5有QFileOpenEvent类来处理OS X适当的事件.
但是:此事件仅在应用程序事件循环开始后才会到达(显然)!

我需要"捕获"并在 main启动之前处理OS X'文件打开事件,因为程序逻辑仅用于处理命令行参数处理.

简化的main功能代码:

int main(int argc, char[]* argv)
{
     QApplication app( argc, argv );

     QStringList arguments = app.arguments();
     if( arguments.count() == argc ) arguments.removeFirst();

     Logic appLogic( NULL, &app );
     app.installMessageHandler( &appLogic );

     // The problem:
     // **This function will always called earlier than the any event**
     if( ! appLogic.start( arguments ) ) return 0;

     // Start processing of events
     // Only after this call Logic class get the desired event
     return app.exec();
}

有没有办法在C++ 函数启动之前获取OS X'文件打开事件main,或者在argv参数中获取"my"文件/ url ？
也许,一些Objective-C黑魔法能胜任这项工作？

注意:start做许多复杂的 - 异步的 - 事情.事件在执行期间到达,因此当异步内容已经工作时很难处理它.所以看起来我只需要阻止start执行,如果事件将到来.

如果应用程序已经打开,则没有问题.

Answer 1

我发现了一个可能很奇怪的解决方案 - 使用Qt'事件系统.

int main(int argc, char[]* argv)
{
    QApplication app( argc, argv );

    QStringList arguments = app.arguments();
    if( arguments.count() == argc ) arguments.removeFirst();

    Logic appLogic( NULL, &app );
    #ifdef Q_OS_MAC
    app.installMessageHandler( &appLogic );

    // Here we should alreasy get FileOpenEvent, if it occurs
    // NOTE: without this FileOpenEvent will arrive LATER
    //       than the DryRunEvent!
    app.processEvents();

    // If there is no file open event in the queue,
    // we should just open the blank program window
    // NOTE: Qt takes ownership of this event object,
    //       so you should not delete it manually
    DryRunEvent* runEv = new DryRunEvent( p );
    a.postEvent( &l, runEv, Qt::LowEventPriority );
    #endif

    ...

    #ifndef Q_OS_MAC
    if( ! appLogic.start( arguments ) ) return 0;
    #endif

    return app.exec();
}

自定义事件标题:

class BaseEvent : public QEvent
{
public:
    BaseEvent( QEvent::Type& eType ) : QEvent( getEventType( eType ) )
    {
    }

    ~BaseEvent() {}

    QEvent::Type getEventType( QEvent::Type& eType )
    {
        if( eType == QEvent::None )
        {
            eType = static_cast<QEvent::Type>( QEvent::registerEventType() );
        }
        return eType;
    }
};

class DryRunEvent : public BaseEvent
{
    QStringList m_params;

    public:
         DryRunEvent( const Parameters& params ) :
             BaseEvent( eventType ), m_params( params )
         {
         }

         ~DryRunEvent(){}

         QStringList GetCmdLineParams() const { return m_params; }

    public:
        static QEvent::Type eventType;
};

自定义事件源:

QEvent::Type ViewerDryRunEvent::eventType = QEvent::None;

逻辑类标题:

class Logic : public QObject
{
    Q_OBJECT
    Q_DISABLE_COPY( Logic )

    public:
        explicit Logic(QObject *parent, QApplication* application);
        virtual ~Logic();

    public slots:
        bool Start( QStringList parameters );
        void ReceiveParameters( QStringList parameters );
        void Stop();

        #ifdef Q_OS_MAC
        bool Logic::WasStarted() const
        {
            ... Determine wether logic was started or not ...
        }
        #endif

    private:
        #ifdef OS_MACOSX
        // Virtual overrided functions
         bool eventFilter( QObject* obj, QEvent* event )
         {
             if( event->type() == QEvent::FileOpen )
             {
                 QFileOpenEvent* fileEvent = static_cast< QFileOpenEvent* >(event);
                 Q_ASSERT( fileEvent != NULL );

                 QString uri;
                 if( fileEvent->file().isEmpty() == false )
                 {
                     uri = fileEvent->file();
                 }
                 else if( fileEvent->url().isEmpty() == false )
                 {
                     uri = fileEvent->url().toString();
                 }

                 if( uri.isEmpty() == false )
                 {
                     if( WasStarted() ) ReceiveParameters( uri );
                     else Start( uri );
                 }

                 return false;
             }
             else if( event->type() == DryRunEvent::eventType )
             {
                 DryRunEvent* myEvent = static_cast< DryRunEvent* >( event );
                 Q_ASSERT( myEvent != NULL );
                 QStringList cmdLineParams = myEvent->GetCmdLineParams();

                 Q_ASSERT( !WasStarted() );
                 if( WasStarted() ) return false;

                 if( !Start( cmdLineParams ) ) m_application->exit( 0 );
                 return false;
             }

             // Standard event processing
             return QObject::eventFilter( obj, event );
        }
        #endif
    };

我希望有人发现这个东西很有用:)