viewselectiontracker.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 "viewselectiontracker.h"
#include <QAbstractItemView>
#include <QItemSelectionModel>
#include <QMouseEvent>
#include <QTimer>
 
namespace LC::Util
{
    ViewSelectionTracker::ViewSelectionTracker (QAbstractItemView& view, QObject* parent)
    : QObject { parent }
    , View_ { view }
    {
        View_.viewport ()->installEventFilter (this);
 
        const auto sm = view.selectionModel ();
        connect (sm,
                &QItemSelectionModel::selectionChanged,
                this,
                &ViewSelectionTracker::HandleSelectionChange);
        connect (sm,
                &QItemSelectionModel::currentRowChanged,
                this,
                &ViewSelectionTracker::HandleSelectionChange);
        connect (view.model (),
                &QAbstractItemModel::modelReset,
                this,
                &ViewSelectionTracker::HandleSelectionChange);
    }
 
    bool ViewSelectionTracker::eventFilter (QObject*, QEvent *ev)
    {
        switch (ev->type ())
        {
        case QEvent::MouseButtonDblClick:
        case QEvent::MouseButtonPress:
            if (static_cast<QMouseEvent*> (ev)->button () == Qt::LeftButton)
            {
                GestureActive_ = true;
                emit gestureStarted ();
            }
            break;
        case QEvent::MouseButtonRelease:
            if (static_cast<QMouseEvent*> (ev)->button () == Qt::LeftButton)
                EndGesture ();
            break;
        case QEvent::UngrabMouse:
            EndGesture ();
            break;
        default:
            break;
        }
 
        return false;
    }
 
    void ViewSelectionTracker::EndGesture ()
    {
        if (std::exchange (GestureActive_, false))
            ScheduleSyncToSelection ();
    }
 
    void ViewSelectionTracker::HandleSelectionChange ()
    {
        emit selectionStartedChanging ();
 
        SelectionDirty_ = true;
        ScheduleSyncToSelection ();
    }
 
    void ViewSelectionTracker::ScheduleSyncToSelection ()
    {
        if (!std::exchange (ScheduledSyncToSelection_, true))
            QTimer::singleShot (0, this, &ViewSelectionTracker::SyncToSelection);
    }
 
    void ViewSelectionTracker::SyncToSelection ()
    {
        if (!std::exchange (ScheduledSyncToSelection_, false))
            return;
 
        if (std::exchange (SelectionDirty_, false))
            emit selectionChanging ();
 
        if (GestureActive_)
            return;
 
        const auto sm = View_.selectionModel ();
        emit selectionSettled (sm->selectedRows (), sm->currentIndex ());
    }
}