From 52e0d9e23c3f7a1b0faf6649cf3dd825bcfd4f08 Mon Sep 17 00:00:00 2001

From: Christian Ehrlicher <ch.ehrlicher@gmx.de>

Date: Thu, 3 Jan 2019 20:33:57 +0100

Subject: [PATCH] Drag'n'Drop: fix dnd when dragMoveEvent() is not implemented

The refactoring of dnd with f8944a7f07112c85dc4f66848cabb490514cd28e

added a regression which results in a need to reimplement

dragMoveEvent() on the drop side. Before this change it was possible to

accept the dnd in dragEnterEvent() without again accepting it in

dragMoveEvent().

Fix it in a similar way it's done in

QGuiApplicationPrivate::processDrag() by prefilling the first simulated

QDragMoveEvent with the values from the previous QDragEnterEvent before

it is sent to the drop receiver.

Fixes: QTBUG-72844

Change-Id: I1300dd02b7f1d9dcd44ecefa8335f92ad6c6cafa

Reviewed-by: Gatis Paeglis <gatis.paeglis@qt.io>

---

 src/widgets/kernel/qwidgetwindow.cpp          |  7 ++--

 .../qwidget_window/tst_qwidget_window.cpp     | 36 ++++++++++++++++---

 2 files changed, 37 insertions(+), 6 deletions(-)

diff --git a/src/widgets/kernel/qwidgetwindow.cpp b/src/widgets/kernel/qwidgetwindow.cpp

index 279c6c0282..991a05fa02 100644

--- src/widgets/kernel/qwidgetwindow.cpp

+++ src/widgets/kernel/qwidgetwindow.cpp

@@ -899,10 +899,10 @@ void QWidgetWindow::handleDragMoveEvent(QDragMoveEvent *event)

         const QPoint mapped = widget->mapFromGlobal(m_widget->mapToGlobal(event->pos()));

         QDragMoveEvent translated(mapped, event->possibleActions(), event->mimeData(),

                                   event->mouseButtons(), event->keyboardModifiers());

-        translated.setDropAction(event->dropAction());

-        translated.setAccepted(event->isAccepted());

         if (widget == m_dragTarget) { // Target widget unchanged: Send DragMove

+            translated.setDropAction(event->dropAction());

+            translated.setAccepted(event->isAccepted());

             QGuiApplication::forwardEvent(m_dragTarget, &translated, event);

         } else {

             if (m_dragTarget) { // Send DragLeave to previous

@@ -912,6 +912,9 @@ void QWidgetWindow::handleDragMoveEvent(QDragMoveEvent *event)

             }

             // Send DragEnter to new widget.

             handleDragEnterEvent(static_cast<QDragEnterEvent*>(event), widget);

+            // Handling 'DragEnter' should suffice for the application.

+            translated.setDropAction(event->dropAction());

+            translated.setAccepted(event->isAccepted());

             // The drag enter event is always immediately followed by a drag move event,

             // see QDragEnterEvent documentation.

             QGuiApplication::forwardEvent(m_dragTarget, &translated, event);

diff --git a/tests/auto/widgets/kernel/qwidget_window/tst_qwidget_window.cpp b/tests/auto/widgets/kernel/qwidget_window/tst_qwidget_window.cpp

index f4da4c3e5f..431d6ba960 100644

--- tests/auto/widgets/kernel/qwidget_window/tst_qwidget_window.cpp

+++ tests/auto/widgets/kernel/qwidget_window/tst_qwidget_window.cpp

@@ -470,6 +470,10 @@ static const char *expectedLogC[] = {

     "Event at 11,241 accepted",

     "acceptingDropsWidget2::dropEvent at 1,51 action=1 MIME_DATA_ADDRESS 'testmimetext'",

     "Event at 11,261 accepted",

+    "acceptingDropsWidget3::dragEnterEvent at 1,21 action=1 MIME_DATA_ADDRESS 'testmimetext'",

+    "Event at 11,281 accepted",

+    "acceptingDropsWidget3::dragLeaveEvent QDragLeaveEvent",

+    "Event at 11,301 ignored",

     "acceptingDropsWidget1::dragEnterEvent at 10,10 action=1 MIME_DATA_ADDRESS 'testmimetext'",

     "Event at 0,0 accepted",

     "acceptingDropsWidget1::dragMoveEvent at 11,11 action=1 MIME_DATA_ADDRESS 'testmimetext'",

@@ -482,8 +486,9 @@ static const char *expectedLogC[] = {

 class DnDEventLoggerWidget : public QWidget

 {

 public:

-    DnDEventLoggerWidget(QStringList *log, QWidget *w = 0) : QWidget(w), m_log(log) {}

-

+    DnDEventLoggerWidget(QStringList *log, QWidget *w = nullptr, bool ignoreDragMove = false)

+        : QWidget(w), m_log(log), m_ignoreDragMove(ignoreDragMove)

+    {}

 protected:

     void dragEnterEvent(QDragEnterEvent *);

     void dragMoveEvent(QDragMoveEvent *);

@@ -493,6 +498,7 @@ protected:

 private:

     void formatDropEvent(const char *function, const QDropEvent *e, QTextStream &str) const;

     QStringList *m_log;

+    bool m_ignoreDragMove;

 };

 void DnDEventLoggerWidget::formatDropEvent(const char *function, const QDropEvent *e, QTextStream &str) const

@@ -513,6 +519,8 @@ void DnDEventLoggerWidget::dragEnterEvent(QDragEnterEvent *e)

 void DnDEventLoggerWidget::dragMoveEvent(QDragMoveEvent *e)

 {

+    if (m_ignoreDragMove)

+        return;

     e->accept();

     QString message;

     QTextStream str(&message);

@@ -580,7 +588,17 @@ void tst_QWidget_window::tst_dnd()

     dropsRefusingWidget2->resize(160, 60);

     dropsRefusingWidget2->move(10, 10);

+    QWidget *dropsAcceptingWidget3 = new DnDEventLoggerWidget(&log, &dndTestWidget, true);

+    dropsAcceptingWidget3->setAcceptDrops(true);

+    dropsAcceptingWidget3->setObjectName(QLatin1String("acceptingDropsWidget3"));

+    // 260 + 40 = 300 = widget size, must not be more than that.

+    // otherwise it will break WinRT because there the tlw is maximized every time

+    // and this window will receive one more event

+    dropsAcceptingWidget3->resize(180, 40);

+    dropsAcceptingWidget3->move(10, 260);

+

     dndTestWidget.show();

+    QVERIFY(QTest::qWaitForWindowExposed(&dndTestWidget));

     qApp->setActiveWindow(&dndTestWidget);

     QVERIFY(QTest::qWaitForWindowActive(&dndTestWidget));

@@ -595,16 +613,17 @@ void tst_QWidget_window::tst_dnd()

     log.push_back(msgEventAccepted(e));

     while (true) {

         position.ry() += 20;

-        if (position.y() >= 250) {

+        if (position.y() >= 250 && position.y() < 270) {

             QDropEvent e(position, Qt::CopyAction, &mimeData, Qt::LeftButton, Qt::NoModifier);

             qApp->sendEvent(window, &e);

             log.push_back(msgEventAccepted(e));

-            break;

         } else {

             QDragMoveEvent e(position, Qt::CopyAction, &mimeData, Qt::LeftButton, Qt::NoModifier);

             qApp->sendEvent(window, &e);

             log.push_back(msgEventAccepted(e));

         }

+        if (position.y() > 290)

+            break;

     }

     window = nativeWidget->windowHandle();

@@ -628,6 +647,15 @@ void tst_QWidget_window::tst_dnd()

     for (int i= 0; i < expectedLogSize; ++i)

         expectedLog.push_back(QString::fromLatin1(expectedLogC[i]).replace(mimeDataAddressPlaceHolder, mimeDataAddress));

+    if (log.size() != expectedLog.size()) {

+        for (int i = 0; i < log.size() && i < expectedLog.size(); ++i)

+            QCOMPARE(log.at(i), expectedLog.at(i));

+        const int iMin = std::min(log.size(), expectedLog.size());

+        for (int i = iMin; i < log.size(); ++i)

+            qDebug() << "log[" << i << "]:" << log.at(i);

+        for (int i = iMin; i < expectedLog.size(); ++i)

+            qDebug() << "exp[" << i << "]:" << log.at(i);

+    }

     QCOMPARE(log, expectedLog);

 }

-- 

2.20.1