Client: Manage QMimeData lifecycle

QMimeData is created by user, it is not taken care of in qtwayland,
which will cause memory leak.

It is now handled in qtwayland that when a new QMimeData is set,
the previous QMimeData is freed.

This is a backport of commit 3af40c6c42703a65656fdd3322183abb2905e44d
which was submitted to dev / 6.6. In hindsight, it was decided it
should have also gone to patch releases, hence this backport.

Pick-to: 5.15 6.2
Change-Id: Ic502021fe700c7ee10454d94f0d1868901809af7
Reviewed-by: David Edmundson <davidedmundson@kde.org>

4 files changed, 22 insertions, 13 deletions

diff --git a/src/client/qwaylandclipboard.cpp b/src/client/qwaylandclipboard.cpp
index d3566244b..df6cf5d2b 100644
--- a/src/client/qwaylandclipboard.cpp
+++ b/src/client/qwaylandclipboard.cpp
@@ -18,10 +18,15 @@ namespace QtWaylandClient {
 QWaylandClipboard::QWaylandClipboard(QWaylandDisplay *display)
     : mDisplay(display)
 {
+    m_clientClipboard[QClipboard::Clipboard] = nullptr;
+    m_clientClipboard[QClipboard::Selection] = nullptr;
 }
 
 QWaylandClipboard::~QWaylandClipboard()
 {
+    if (m_clientClipboard[QClipboard::Clipboard] != m_clientClipboard[QClipboard::Selection])
+        delete m_clientClipboard[QClipboard::Clipboard];
+    delete m_clientClipboard[QClipboard::Selection];
 }
 
 QMimeData *QWaylandClipboard::mimeData(QClipboard::Mode mode)
@@ -33,8 +38,8 @@ QMimeData *QWaylandClipboard::mimeData(QClipboard::Mode mode)
     switch (mode) {
     case QClipboard::Clipboard:
         if (auto *dataDevice = seat->dataDevice()) {
-            if (auto *source = dataDevice->selectionSource())
-                return source->mimeData();
+            if (dataDevice->selectionSource())
+                return m_clientClipboard[QClipboard::Clipboard];
             if (auto *offer = dataDevice->selectionOffer())
                 return offer->mimeData();
         }
@@ -42,8 +47,8 @@ QMimeData *QWaylandClipboard::mimeData(QClipboard::Mode mode)
     case QClipboard::Selection:
 #if QT_CONFIG(wayland_client_primary_selection)
         if (auto *selectionDevice = seat->primarySelectionDevice()) {
-            if (auto *source = selectionDevice->selectionSource())
-                return source->mimeData();
+            if (selectionDevice->selectionSource())
+                return m_clientClipboard[QClipboard::Selection];
             if (auto *offer = selectionDevice->selectionOffer())
                 return offer->mimeData();
         }
@@ -68,17 +73,27 @@ void QWaylandClipboard::setMimeData(QMimeData *data, QClipboard::Mode mode)
     if (data && data->hasFormat(plain) && !data->hasFormat(utf8))
         data->setData(utf8, data->data(plain));
 
+    if (m_clientClipboard[mode]) {
+        if (m_clientClipboard[QClipboard::Clipboard] != m_clientClipboard[QClipboard::Selection])
+            delete m_clientClipboard[mode];
+        m_clientClipboard[mode] = nullptr;
+    }
+
+    m_clientClipboard[mode] = data;
+
     switch (mode) {
     case QClipboard::Clipboard:
         if (auto *dataDevice = seat->dataDevice()) {
-            dataDevice->setSelectionSource(data ? new QWaylandDataSource(mDisplay->dndSelectionHandler(), data) : nullptr);
+            dataDevice->setSelectionSource(data ? new QWaylandDataSource(mDisplay->dndSelectionHandler(),
+                                                                         m_clientClipboard[QClipboard::Clipboard]) : nullptr);
             emitChanged(mode);
         }
         break;
     case QClipboard::Selection:
 #if QT_CONFIG(wayland_client_primary_selection)
         if (auto *selectionDevice = seat->primarySelectionDevice()) {
-            selectionDevice->setSelectionSource(data ? new QWaylandPrimarySelectionSourceV1(mDisplay->primarySelectionManager(), data) : nullptr);
+            selectionDevice->setSelectionSource(data ? new QWaylandPrimarySelectionSourceV1(mDisplay->primarySelectionManager(),
+                                                                                            m_clientClipboard[QClipboard::Selection]) : nullptr);
             emitChanged(mode);
         }
 #endif
diff --git a/src/client/qwaylandclipboard_p.h b/src/client/qwaylandclipboard_p.h
index 655620bda..414e3dc71 100644
--- a/src/client/qwaylandclipboard_p.h
+++ b/src/client/qwaylandclipboard_p.h
@@ -45,6 +45,7 @@ public:
 private:
     QWaylandDisplay *mDisplay = nullptr;
     QMimeData m_emptyData;
+    QMimeData *m_clientClipboard[2];
 };
 
 }
diff --git a/src/client/qwaylanddatasource.cpp b/src/client/qwaylanddatasource.cpp
index 093c40f2f..966d5ef7f 100644
--- a/src/client/qwaylanddatasource.cpp
+++ b/src/client/qwaylanddatasource.cpp
@@ -36,11 +36,6 @@ QWaylandDataSource::~QWaylandDataSource()
     destroy();
 }
 
-QMimeData * QWaylandDataSource::mimeData() const
-{
-    return m_mime_data;
-}
-
 void QWaylandDataSource::data_source_cancelled()
 {
     Q_EMIT cancelled();
diff --git a/src/client/qwaylanddatasource_p.h b/src/client/qwaylanddatasource_p.h
index 0ce09a409..a4b317c26 100644
--- a/src/client/qwaylanddatasource_p.h
+++ b/src/client/qwaylanddatasource_p.h
@@ -38,8 +38,6 @@ public:
     QWaylandDataSource(QWaylandDataDeviceManager *dataDeviceManager, QMimeData *mimeData);
     ~QWaylandDataSource() override;
 
-    QMimeData *mimeData() const;
-
 Q_SIGNALS:
     void cancelled();
     void finished();