Resolves: rhbz#1326304 cannot detect loss of wayland clipboard ownership

gtk_clipboard_get_owner always returns what you set with
gtk_clipboard_set_with_owner and that doesn't change if some other
application takes over the clipboard

The "owner-change" signal doesn't contain any useful data under wayland,
and doesn't fire when you'd expect either, just when the app becomes
active or gets focus or something like that. So you get it when you
do have the clipboard and when you don't, so that's no use either to
detect loss of clipboard ownership

So, forget about clipboard ownership, and always take the data to
be pasted from the system clipboard, so when we are pasting from ourselves
its "paste"->m_aSystemContents->gtk->"copy"->m_aOurContents

Undoubtedly something else will break now

Change-Id: I32f2e1a2cc3310687f61a094fdfa940fa0cfcc39

1 files changed, 19 insertions, 94 deletions

diff --git a/vcl/unx/gtk3/gtk3gtkinst.cxx b/vcl/unx/gtk3/gtk3gtkinst.cxx
index ed64ded2ece5..262478f7d12d 100644
--- a/vcl/unx/gtk3/gtk3gtkinst.cxx
+++ b/vcl/unx/gtk3/gtk3gtkinst.cxx
@@ -238,47 +238,6 @@ public:
     }
 };
 
-//We want to use gtk_clipboard_get_owner own owner-change to distinguish between
-//us gaining the clipboard ownership vs losing it. To do that we need to use
-//gtk_clipboard_set_with_owner and to do that we need a GObject, so define
-//one here for that purpose and just give it a VclGtkClipboard* member
-class VclGtkClipboard;
-
-struct ClipboardOwner
-{
-    GObject parent_instance;
-
-    /* instance members */
-    VclGtkClipboard* m_pThis;
-};
-
-struct ClipboardOwnerClass
-{
-  GObjectClass parent_class;
-
-  /* class members */
-};
-
-#define CLIPBOARD_OWNER_OBJECT           (clipboard_owner_get_type ())
-#define CLIPBOARD_OWNER(obj)             (G_TYPE_CHECK_INSTANCE_CAST ((obj), CLIPBOARD_OWNER_OBJECT, ClipboardOwner))
-
-#ifdef __GNUC__
-#pragma GCC diagnostic push
-#pragma GCC diagnostic ignored "-Wunused-function"
-#endif
-G_DEFINE_TYPE(ClipboardOwner, clipboard_owner, G_TYPE_OBJECT);
-#ifdef __GNUC__
-#pragma GCC diagnostic pop
-#endif
-
-static void clipboard_owner_class_init (ClipboardOwnerClass *)
-{
-}
-
-static void clipboard_owner_init(ClipboardOwner *)
-{
-}
-
 class VclGtkClipboard :
         public cppu::WeakComponentImplHelper<
         datatransfer::clipboard::XSystemClipboard,
@@ -287,9 +246,8 @@ class VclGtkClipboard :
 {
     GdkAtom                                                  m_nSelection;
     osl::Mutex                                               m_aMutex;
-    ClipboardOwner*                                          m_pOwner;
-    gulong                                                   m_nOwnerChangedSignalId;
-    Reference<css::datatransfer::XTransferable>              m_aContents;
+    Reference<css::datatransfer::XTransferable>              m_aOurContents;
+    Reference<css::datatransfer::XTransferable>              m_aSystemContents;
     Reference<css::datatransfer::clipboard::XClipboardOwner> m_aOwner;
     std::list< Reference<css::datatransfer::clipboard::XClipboardListener> > m_aListeners;
     std::vector<GtkTargetEntry> m_aGtkTargets;
@@ -349,7 +307,6 @@ public:
 
     void ClipboardGet(GtkClipboard *clipboard, GtkSelectionData *selection_data, guint info);
     void ClipboardClear(GtkClipboard *clipboard);
-    void OwnerChanged(GtkClipboard *clipboard, GdkEvent *event);
 };
 
 OUString VclGtkClipboard::getImplementationName() throw( RuntimeException, std::exception )
@@ -370,33 +327,17 @@ sal_Bool VclGtkClipboard::supportsService( const OUString& ServiceName ) throw(
 
 Reference< css::datatransfer::XTransferable > VclGtkClipboard::getContents() throw( RuntimeException, std::exception )
 {
-    if (G_OBJECT(m_pOwner) != gtk_clipboard_get_owner(gtk_clipboard_get(m_nSelection)) &&
-        !m_aContents.is())
-    {
-        //tdf#93887 This is the system clipboard/selection. We fetch it when we are not
-        //the owner of the clipboard and have not already fetched it.
-        m_aContents = new GtkClipboardTransferable(m_nSelection);
-    }
-    return m_aContents;
+    if (!m_aSystemContents.is())
+        m_aSystemContents= new GtkClipboardTransferable(m_nSelection);
+    return m_aSystemContents;
 }
 
 void VclGtkClipboard::ClipboardGet(GtkClipboard* /*clipboard*/, GtkSelectionData *selection_data,
                                    guint info)
 {
-    if (!m_aContents.is())
+    if (!m_aOurContents.is())
         return;
-    m_aConversionHelper.setSelectionData(m_aContents, selection_data, info);
-}
-
-void VclGtkClipboard::OwnerChanged(GtkClipboard* clipboard, GdkEvent* /*event*/)
-{
-    if (G_OBJECT(m_pOwner) != gtk_clipboard_get_owner(clipboard))
-    {
-        //null out m_aContents to return control to the system-one which
-        //will be retrieved if getContents is called again
-        setContents(Reference<css::datatransfer::XTransferable>(),
-                    Reference<css::datatransfer::clipboard::XClipboardOwner>());
-    }
+    m_aConversionHelper.setSelectionData(m_aOurContents, selection_data, info);
 }
 
 void VclGtkClipboard::ClipboardClear(GtkClipboard * /*clipboard*/)
@@ -488,21 +429,15 @@ namespace
                           guint info,
                           gpointer user_data_or_owner)
     {
-        VclGtkClipboard* pThis = CLIPBOARD_OWNER(user_data_or_owner)->m_pThis;
+        VclGtkClipboard* pThis = reinterpret_cast<VclGtkClipboard*>(user_data_or_owner);
         pThis->ClipboardGet(clipboard, selection_data, info);
     }
 
     void ClipboardClearFunc(GtkClipboard *clipboard, gpointer user_data_or_owner)
     {
-        VclGtkClipboard* pThis = CLIPBOARD_OWNER(user_data_or_owner)->m_pThis;
+        VclGtkClipboard* pThis = reinterpret_cast<VclGtkClipboard*>(user_data_or_owner);
         pThis->ClipboardClear(clipboard);
     }
-
-    void handle_owner_change(GtkClipboard *clipboard, GdkEvent *event, gpointer user_data)
-    {
-        VclGtkClipboard* pThis = static_cast<VclGtkClipboard*>(user_data);
-        pThis->OwnerChanged(clipboard, event);
-    }
 }
 
 VclGtkClipboard::VclGtkClipboard(GdkAtom nSelection)
@@ -511,11 +446,6 @@ VclGtkClipboard::VclGtkClipboard(GdkAtom nSelection)
         (m_aMutex)
     , m_nSelection(nSelection)
 {
-    GtkClipboard* clipboard = gtk_clipboard_get(m_nSelection);
-    m_nOwnerChangedSignalId = g_signal_connect(clipboard, "owner-change",
-                                               G_CALLBACK(handle_owner_change), this);
-    m_pOwner = CLIPBOARD_OWNER(g_object_new(CLIPBOARD_OWNER_OBJECT, nullptr));
-    m_pOwner->m_pThis = this;
 }
 
 void VclGtkClipboard::flushClipboard()
@@ -532,9 +462,6 @@ void VclGtkClipboard::flushClipboard()
 
 VclGtkClipboard::~VclGtkClipboard()
 {
-    GtkClipboard* clipboard = gtk_clipboard_get(m_nSelection);
-    g_signal_handler_disconnect(clipboard, m_nOwnerChangedSignalId);
-    g_object_unref(m_pOwner);
     ClipboardClear(nullptr);
 }
 
@@ -586,28 +513,26 @@ void VclGtkClipboard::setContents(
 {
     osl::ClearableMutexGuard aGuard( m_aMutex );
     Reference< datatransfer::clipboard::XClipboardOwner > xOldOwner( m_aOwner );
-    Reference< datatransfer::XTransferable > xOldContents( m_aContents );
-    m_aContents = xTrans;
+    Reference< datatransfer::XTransferable > xOldContents(m_aOurContents);
+    m_aOurContents = xTrans;
     m_aOwner = xClipboardOwner;
 
     std::list< Reference< datatransfer::clipboard::XClipboardListener > > aListeners( m_aListeners );
     datatransfer::clipboard::ClipboardEvent aEv;
 
-    if (m_aContents.is())
+    //if there was a previous gtk_clipboard_set_with_data call then
+    //ClipboardClearFunc will be called now
+    GtkClipboard* clipboard = gtk_clipboard_get(m_nSelection);
+    gtk_clipboard_clear(clipboard);
+
+    if (m_aOurContents.is())
     {
         css::uno::Sequence<css::datatransfer::DataFlavor> aFormats = xTrans->getTransferDataFlavors();
         std::vector<GtkTargetEntry> aGtkTargets(m_aConversionHelper.FormatsToGtk(aFormats));
         if (!aGtkTargets.empty())
         {
-            //if there was a previous gtk_clipboard_set_with_data call then
-            //ClipboardClearFunc will be called now
-            GtkClipboard* clipboard = gtk_clipboard_get(m_nSelection);
-            if(G_OBJECT(m_pOwner) == gtk_clipboard_get_owner(clipboard))
-                gtk_clipboard_clear(clipboard);
-            //use with_owner with m_pOwner so we can distinguish in handle_owner_change
-            //if we have gained or lost ownership of the clipboard
-            gtk_clipboard_set_with_owner(clipboard, aGtkTargets.data(), aGtkTargets.size(),
-                                        ClipboardGetFunc, ClipboardClearFunc, G_OBJECT(m_pOwner));
+            gtk_clipboard_set_with_data(clipboard, aGtkTargets.data(), aGtkTargets.size(),
+                                        ClipboardGetFunc, ClipboardClearFunc, this);
             gtk_clipboard_set_can_store(clipboard, aGtkTargets.data(), aGtkTargets.size());
         }