Adding upstream version 4:7.4.7.upstream/4%7.4.7upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 646 insertions, 0 deletions

diff --git a/vcl/win/dtrans/target.cxx b/vcl/win/dtrans/target.cxx
new file mode 100644
index 000000000..077aeeb0d
--- /dev/null
+++ b/vcl/win/dtrans/target.cxx
@@ -0,0 +1,646 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/*
+ * This file is part of the LibreOffice project.
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ *
+ * This file incorporates work covered by the following license notice:
+ *
+ *   Licensed to the Apache Software Foundation (ASF) under one or more
+ *   contributor license agreements. See the NOTICE file distributed
+ *   with this work for additional information regarding copyright
+ *   ownership. The ASF licenses this file to you under the Apache
+ *   License, Version 2.0 (the "License"); you may not use this file
+ *   except in compliance with the License. You may obtain a copy of
+ *   the License at http://www.apache.org/licenses/LICENSE-2.0 .
+ */
+
+#include <com/sun/star/datatransfer/dnd/DNDConstants.hpp>
+#include <com/sun/star/datatransfer/XTransferable.hpp>
+#include <cppuhelper/supportsservice.hxx>
+#include <o3tl/any.hxx>
+
+#include <stdio.h>
+#include <win/dnd_target.hxx>
+#include "idroptarget.hxx"
+#include "globals.hxx"
+#include "targetdropcontext.hxx"
+#include "targetdragcontext.hxx"
+#include <rtl/ustring.h>
+#include <osl/thread.h>
+#include <sal/log.hxx>
+#include <comphelper/windowserrorstring.hxx>
+
+#include "DOTransferable.hxx"
+
+using namespace cppu;
+using namespace osl;
+using namespace com::sun::star::datatransfer;
+using namespace com::sun::star::datatransfer::dnd;
+using namespace com::sun::star::datatransfer::dnd::DNDConstants;
+
+#define WM_REGISTERDRAGDROP WM_USER + 1
+#define WM_REVOKEDRAGDROP WM_USER + 2
+
+DWORD WINAPI DndTargetOleSTAFunc(LPVOID pParams);
+
+DropTarget::DropTarget( const Reference<XComponentContext>& rxContext):
+    WeakComponentImplHelper<XInitialization,XDropTarget, XServiceInfo>(m_aMutex),
+    m_hWnd( nullptr),
+    m_threadIdWindow(0),
+    m_threadIdTarget(0),
+    m_hOleThread(nullptr),
+    m_oleThreadId( 0),
+    m_pDropTarget( nullptr),
+    m_xContext( rxContext ),
+    m_bActive(true),
+    m_nDefaultActions(ACTION_COPY|ACTION_MOVE|ACTION_LINK|ACTION_DEFAULT),
+    m_nCurrentDropAction( ACTION_NONE),
+    m_nLastDropAction(0),
+    m_bDropComplete(false)
+{
+}
+
+DropTarget::~DropTarget()
+{
+}
+// called from WeakComponentImplHelperX::dispose
+// WeakComponentImplHelper calls disposing before it destroys
+// itself.
+// NOTE: RevokeDragDrop decrements the ref count on the IDropTarget
+// interface. (m_pDropTarget)
+// If the HWND is invalid then it doesn't decrement and
+// the IDropTarget object will live on. MEMORY LEAK
+void SAL_CALL DropTarget::disposing()
+{
+    if( m_threadIdTarget)
+    {
+        // Call RevokeDragDrop and wait for the OLE thread to die;
+        PostThreadMessageW( m_threadIdTarget, WM_REVOKEDRAGDROP, reinterpret_cast<WPARAM>(this), 0);
+        WaitForSingleObject( m_hOleThread, INFINITE);
+        CloseHandle( m_hOleThread);
+        //OSL_ENSURE( SUCCEEDED( hr), "HWND not valid!" );
+    }
+    else
+    {
+        RevokeDragDrop( m_hWnd);
+        m_hWnd= nullptr;
+    }
+    if( m_pDropTarget)
+    {
+        CoLockObjectExternal( m_pDropTarget, FALSE, TRUE);
+        m_pDropTarget->Release();
+        m_pDropTarget = nullptr;
+    }
+
+    if( m_oleThreadId)
+    {
+        if( m_oleThreadId == CoGetCurrentProcess() )
+            OleUninitialize();
+    }
+
+}
+
+void SAL_CALL DropTarget::initialize( const Sequence< Any >& aArguments )
+{
+    // The window must be registered for Dnd by RegisterDragDrop. We must ensure
+    // that RegisterDragDrop is called from an STA ( OleInitialize) thread.
+    // As long as the window is registered we need to receive OLE messages in
+    // an OLE thread. That is to say, if DropTarget::initialize was called from an
+    // MTA thread then we create an OLE thread in which the window is registered.
+    // The thread will stay alive until aver RevokeDragDrop has been called.
+
+    // Additionally even if RegisterDragDrop is called from an STA thread we have
+    // to ensure that it is called from the same thread that created the Window
+    // otherwise messages sent during DND won't reach the windows message queue.
+    // Calling AttachThreadInput first would resolve this problem but would block
+    // the message queue of the calling thread. So if the current thread
+    // (even if it's an STA thread) and the thread that created the window are not
+    // identical we need to create a new thread as we do when the calling thread is
+    // an MTA thread.
+
+    if( aArguments.getLength() > 0)
+    {
+        // Get the window handle from aArgument. It is needed for RegisterDragDrop.
+        m_hWnd= reinterpret_cast<HWND>(static_cast<sal_uIntPtr>(*o3tl::doAccess<sal_uInt64>(aArguments[0])));
+        OSL_ASSERT( IsWindow( m_hWnd) );
+
+        // Obtain the id of the thread that created the window
+        m_threadIdWindow= GetWindowThreadProcessId( m_hWnd, nullptr);
+
+        HRESULT hr= OleInitialize( nullptr);
+
+        // Current thread is MTA or Current thread and Window thread are not identical
+        if( hr == RPC_E_CHANGED_MODE || GetCurrentThreadId() != m_threadIdWindow  )
+        {
+            OSL_ENSURE( ! m_threadIdTarget,"initialize was called twice");
+            // create the IDropTargetImplementation
+            m_pDropTarget= new IDropTargetImpl( *this );
+            m_pDropTarget->AddRef();
+
+            // Obtain the id of the thread that created the window
+            m_threadIdWindow= GetWindowThreadProcessId( m_hWnd, nullptr);
+            // The event is set by the thread that we will create momentarily.
+            // It indicates that the thread is ready to receive messages.
+            HANDLE m_evtThreadReady= CreateEventW( nullptr, FALSE, FALSE, nullptr);
+
+            m_hOleThread= CreateThread( nullptr, 0, DndTargetOleSTAFunc,
+                                            &m_evtThreadReady, 0, &m_threadIdTarget);
+            WaitForSingleObject( m_evtThreadReady, INFINITE);
+            CloseHandle( m_evtThreadReady);
+            PostThreadMessageW( m_threadIdTarget, WM_REGISTERDRAGDROP, reinterpret_cast<WPARAM>(this), 0);
+        }
+        else if( hr == S_OK || hr == S_FALSE)
+        {
+            // current thread is STA
+            // If OleInitialize has been called by the caller then we must not call
+            // OleUninitialize
+            if( hr == S_OK)
+            {
+                // caller did not call OleInitialize, so we call OleUninitialize
+                // remember the thread that will call OleUninitialize
+                m_oleThreadId= CoGetCurrentProcess(); // get a unique thread id
+            }
+
+            // Get the window handle from aArgument. It is needed for RegisterDragDrop.
+            // create the IDropTargetImplementation
+            m_pDropTarget= new IDropTargetImpl( *this );
+            m_pDropTarget->AddRef();
+            // CoLockObjectExternal is prescribed by the protocol. It bumps up the ref count
+            if( SUCCEEDED( CoLockObjectExternal( m_pDropTarget, TRUE, FALSE)))
+            {
+                if( FAILED( RegisterDragDrop( m_hWnd,  m_pDropTarget) ) )
+                {
+                    // do clean up if drag and drop is not possible
+                    CoLockObjectExternal( m_pDropTarget, FALSE, FALSE);
+                    m_pDropTarget->Release();
+                    m_pDropTarget = nullptr;
+                    m_hWnd= nullptr;
+                }
+            }
+        }
+        else
+            throw Exception("OleInitialize failed with " + OUString::number(hr), nullptr);
+
+    }
+}
+
+// This function is called as extra thread from DragSource::startDrag.
+// The function carries out a drag and drop operation by calling
+// DoDragDrop. The thread also notifies all XSourceListener.
+DWORD WINAPI DndTargetOleSTAFunc(LPVOID pParams)
+{
+    osl_setThreadName("DropTarget DndTargetOleSTAFunc");
+
+    HRESULT hr= OleInitialize( nullptr);
+    if( SUCCEEDED( hr) )
+    {
+        MSG msg;
+        // force the creation of a message queue
+        PeekMessageW( &msg, nullptr, 0, 0, PM_NOREMOVE);
+        // Signal the creator ( DropTarget::initialize) that the thread is
+        // ready to receive messages.
+        SetEvent( *static_cast<HANDLE*>(pParams));
+        // Thread id is needed for attaching this message queue to the one of the
+        // thread where the window was created.
+        DWORD threadId= GetCurrentThreadId();
+        // We force the creation of a thread message queue. This is necessary
+        // for a later call to AttachThreadInput
+        for (;;)
+        {
+            int const bRet = GetMessageW(&msg, nullptr, 0, 0);
+            if (bRet == 0)
+            {
+                break;
+            }
+            if (-1 == bRet)
+            {
+                SAL_WARN("vcl.win.dtrans", "GetMessageW failed: " << WindowsErrorString(GetLastError()));
+                break;
+            }
+            if( msg.message == WM_REGISTERDRAGDROP)
+            {
+                DropTarget *pTarget= reinterpret_cast<DropTarget*>(msg.wParam);
+                // This thread is attached to the thread that created the window. Hence
+                // this thread also receives all mouse and keyboard messages which are
+                // needed
+                AttachThreadInput( threadId , pTarget->m_threadIdWindow, TRUE );
+
+                if( SUCCEEDED( CoLockObjectExternal(pTarget-> m_pDropTarget, TRUE, FALSE)))
+                {
+                    if( FAILED( RegisterDragDrop( pTarget-> m_hWnd, pTarget-> m_pDropTarget) ) )
+                    {
+                        // do clean up if drag and drop is not possible
+                        CoLockObjectExternal( pTarget->m_pDropTarget, FALSE, FALSE);
+                        pTarget->m_pDropTarget->Release();
+                        pTarget->m_pDropTarget = nullptr;
+                        pTarget->m_hWnd= nullptr;
+                    }
+                }
+            }
+            else if( msg.message == WM_REVOKEDRAGDROP)
+            {
+                DropTarget *pTarget= reinterpret_cast<DropTarget*>(msg.wParam);
+                RevokeDragDrop( pTarget-> m_hWnd);
+                // Detach this thread from the window thread
+                AttachThreadInput( threadId, pTarget->m_threadIdWindow, FALSE);
+                pTarget->m_hWnd= nullptr;
+                break;
+            }
+            TranslateMessage(  &msg);
+            DispatchMessageW( &msg);
+        }
+        OleUninitialize();
+    }
+    return 0;
+}
+
+// XServiceInfo
+OUString SAL_CALL DropTarget::getImplementationName(  )
+{
+    return "com.sun.star.comp.datatransfer.dnd.OleDropTarget_V1";
+}
+// XServiceInfo
+sal_Bool SAL_CALL DropTarget::supportsService( const OUString& ServiceName )
+{
+    return cppu::supportsService(this, ServiceName);
+}
+
+Sequence< OUString > SAL_CALL DropTarget::getSupportedServiceNames(  )
+{
+    return { "com.sun.star.datatransfer.dnd.OleDropTarget" };
+}
+
+// XDropTarget
+void SAL_CALL DropTarget::addDropTargetListener( const Reference< XDropTargetListener >& dtl )
+{
+    rBHelper.addListener( cppu::UnoType<decltype(dtl)>::get(), dtl );
+}
+
+void SAL_CALL DropTarget::removeDropTargetListener( const Reference< XDropTargetListener >& dtl )
+{
+    rBHelper.removeListener( cppu::UnoType<decltype(dtl)>::get(), dtl );
+}
+
+sal_Bool SAL_CALL DropTarget::isActive(  )
+{
+    return m_bActive; //m_bDropTargetRegistered;
+}
+
+void SAL_CALL DropTarget::setActive( sal_Bool _b )
+{
+    MutexGuard g(m_aMutex);
+    m_bActive= _b;
+}
+
+sal_Int8 SAL_CALL DropTarget::getDefaultActions(  )
+{
+    return m_nDefaultActions;
+}
+
+void SAL_CALL DropTarget::setDefaultActions( sal_Int8 actions )
+{
+    OSL_ENSURE( actions < 8, "No valid default actions");
+    m_nDefaultActions= actions;
+}
+
+HRESULT DropTarget::DragEnter( IDataObject *pDataObj,
+                                    DWORD grfKeyState,
+                                    POINTL pt,
+                                    DWORD  *pdwEffect)
+{
+#if defined DBG_CONSOLE_OUT
+    printf("\nDropTarget::DragEnter state: %x effect %d", grfKeyState, *pdwEffect);
+#endif
+    if( m_bActive )
+    {
+        // Intersection of pdwEffect and the allowed actions ( setDefaultActions)
+        m_nCurrentDropAction= getFilteredActions( grfKeyState, *pdwEffect);
+        // m_nLastDropAction has to be set by a listener. If no listener calls
+        //XDropTargetDragContext::acceptDrag and specifies an action then pdwEffect
+        // will be DROPEFFECT_NONE throughout
+        m_nLastDropAction= ACTION_DEFAULT | ACTION_MOVE;
+
+        m_currentDragContext = new TargetDragContext(this);
+
+        //--> TRA
+
+        // shortcut
+        if ( g_XTransferable.is( ) )
+            m_currentData = g_XTransferable;
+        else
+        {
+            // Convert the IDataObject to a XTransferable
+            m_currentData = new CDOTransferable(m_xContext, IDataObjectPtr(pDataObj));
+        }
+
+        //<-- TRA
+
+        if( m_nCurrentDropAction != ACTION_NONE)
+        {
+            DropTargetDragEnterEvent e;
+            e.SupportedDataFlavors= m_currentData->getTransferDataFlavors();
+            e.DropAction= m_nCurrentDropAction;
+            e.Source.set( static_cast<XDropTarget*>(this),UNO_QUERY);
+            e.Context= m_currentDragContext;
+            POINT point={ pt.x, pt.y};
+            ScreenToClient( m_hWnd, &point);
+            e.LocationX= point.x;
+            e.LocationY= point.y;
+            e.SourceActions= dndOleDropEffectsToActions( *pdwEffect);
+
+            fire_dragEnter( e);
+            // Check if the action derived from grfKeyState (m_nCurrentDropAction) or the action set
+            // by the listener (m_nCurrentDropAction) is allowed by the source. Only an allowed action is set
+            // in pdwEffect. The listener notification is asynchronous, that is we cannot expect that the listener
+            // has already reacted to the notification.
+            // If there is more than one valid action which is the case when ALT or RIGHT MOUSE BUTTON is pressed
+            // then getDropEffect returns DROPEFFECT_MOVE which is the default value if no other modifier is pressed.
+            // On drop the target should present the user a dialog from which the user may change the action.
+            sal_Int8 allowedActions= dndOleDropEffectsToActions( *pdwEffect);
+            *pdwEffect= dndActionsToSingleDropEffect( m_nLastDropAction & allowedActions);
+        }
+        else
+        {
+            *pdwEffect= DROPEFFECT_NONE;
+        }
+    }
+    return S_OK;
+}
+
+HRESULT DropTarget::DragOver( DWORD grfKeyState,
+                                   POINTL pt,
+                                   DWORD  *pdwEffect)
+{
+    if( m_bActive)
+    {
+        m_nCurrentDropAction= getFilteredActions( grfKeyState, *pdwEffect);
+
+        if( m_nCurrentDropAction)
+        {
+            DropTargetDragEvent e;
+            e.DropAction= m_nCurrentDropAction;
+            e.Source.set(static_cast<XDropTarget*>(this),UNO_QUERY);
+            e.Context= m_currentDragContext;
+            POINT point={ pt.x, pt.y};
+            ScreenToClient( m_hWnd, &point);
+            e.LocationX= point.x;
+            e.LocationY= point.y;
+            e.SourceActions= dndOleDropEffectsToActions( *pdwEffect);
+
+            // if grfKeyState has changed since the last DragOver then fire events.
+            // A listener might change m_nCurrentDropAction by calling the
+            // XDropTargetDragContext::acceptDrag function. But this is not important
+            // because in the afterwards fired dragOver event the action reflects
+            // grgKeyState again.
+            if( m_nLastDropAction != m_nCurrentDropAction)
+                fire_dropActionChanged( e);
+
+            // The Event contains a XDropTargetDragContext implementation.
+            fire_dragOver( e);
+            // Check if the action derived from grfKeyState (m_nCurrentDropAction) or the action set
+            // by the listener (m_nCurrentDropAction) is allowed by the source. Only an allowed action is set
+            // in pdwEffect. The listener notification is asynchronous, that is we cannot expect that the listener
+            // has already reacted to the notification.
+            // If there is more than one valid action which is the case when ALT or RIGHT MOUSE BUTTON is pressed
+            // then getDropEffect returns DROPEFFECT_MOVE which is the default value if no other modifier is pressed.
+            // On drop the target should present the user a dialog from which the user may change the action.
+            sal_Int8 allowedActions= dndOleDropEffectsToActions( *pdwEffect);
+            // set the last action to the current if listener has not changed the value yet
+            *pdwEffect= dndActionsToSingleDropEffect( m_nLastDropAction & allowedActions);
+        }
+        else
+        {
+            *pdwEffect= DROPEFFECT_NONE;
+        }
+    }
+#if defined DBG_CONSOLE_OUT
+    printf("\nDropTarget::DragOver %d", *pdwEffect );
+#endif
+    return S_OK;
+}
+
+HRESULT DropTarget::DragLeave()
+{
+#if defined DBG_CONSOLE_OUT
+    printf("\nDropTarget::DragLeave");
+#endif
+    if( m_bActive)
+    {
+
+        m_currentData=nullptr;
+        m_currentDragContext= nullptr;
+        m_currentDropContext= nullptr;
+        m_nLastDropAction= 0;
+
+        if( m_nDefaultActions != ACTION_NONE)
+        {
+            DropTargetEvent e;
+            e.Source=  static_cast<XDropTarget*>(this);
+
+            fire_dragExit( e);
+        }
+    }
+    return S_OK;
+}
+
+HRESULT DropTarget::Drop( IDataObject  * /*pDataObj*/,
+                   DWORD grfKeyState,
+                   POINTL pt,
+                   DWORD *pdwEffect)
+{
+#if defined DBG_CONSOLE_OUT
+    printf("\nDropTarget::Drop");
+#endif
+    if( m_bActive)
+    {
+
+        m_bDropComplete= false;
+
+        m_nCurrentDropAction= getFilteredActions( grfKeyState, *pdwEffect);
+        m_currentDropContext = new TargetDropContext(this);
+        if( m_nCurrentDropAction)
+        {
+            DropTargetDropEvent e;
+            e.DropAction= m_nCurrentDropAction;
+            e.Source.set( static_cast<XDropTarget*>(this), UNO_QUERY);
+            e.Context= m_currentDropContext;
+            POINT point={ pt.x, pt.y};
+            ScreenToClient( m_hWnd, &point);
+            e.LocationX= point.x;
+            e.LocationY= point.y;
+            e.SourceActions= dndOleDropEffectsToActions( *pdwEffect);
+            e.Transferable= m_currentData;
+            fire_drop( e);
+
+            //if fire_drop returns than a listener might have modified m_nCurrentDropAction
+            if( m_bDropComplete )
+            {
+                sal_Int8 allowedActions= dndOleDropEffectsToActions( *pdwEffect);
+                *pdwEffect= dndActionsToSingleDropEffect( m_nCurrentDropAction & allowedActions);
+            }
+            else
+                *pdwEffect= DROPEFFECT_NONE;
+        }
+        else
+            *pdwEffect= DROPEFFECT_NONE;
+
+        m_currentData= nullptr;
+        m_currentDragContext= nullptr;
+        m_currentDropContext= nullptr;
+        m_nLastDropAction= 0;
+    }
+    return S_OK;
+}
+
+void DropTarget::fire_drop( const DropTargetDropEvent& dte)
+{
+    OInterfaceContainerHelper* pContainer= rBHelper.getContainer( cppu::UnoType<XDropTargetListener>::get());
+    if( pContainer)
+    {
+        OInterfaceIteratorHelper iter( *pContainer);
+        while( iter.hasMoreElements())
+        {
+            Reference<XDropTargetListener> listener( static_cast<XDropTargetListener*>( iter.next()));
+            listener->drop( dte);
+        }
+    }
+}
+
+void DropTarget::fire_dragEnter( const DropTargetDragEnterEvent& e )
+{
+    OInterfaceContainerHelper* pContainer= rBHelper.getContainer( cppu::UnoType<XDropTargetListener>::get());
+    if( pContainer)
+    {
+        OInterfaceIteratorHelper iter( *pContainer);
+        while( iter.hasMoreElements())
+        {
+            Reference<XDropTargetListener> listener( static_cast<XDropTargetListener*>( iter.next()));
+            listener->dragEnter( e);
+        }
+    }
+}
+
+void DropTarget::fire_dragExit( const DropTargetEvent& dte )
+{
+    OInterfaceContainerHelper* pContainer= rBHelper.getContainer( cppu::UnoType<XDropTargetListener>::get());
+
+    if( pContainer)
+    {
+        OInterfaceIteratorHelper iter( *pContainer);
+        while( iter.hasMoreElements())
+        {
+            Reference<XDropTargetListener> listener( static_cast<XDropTargetListener*>( iter.next()));
+            listener->dragExit( dte);
+        }
+    }
+}
+
+void DropTarget::fire_dragOver( const DropTargetDragEvent& dtde )
+{
+    OInterfaceContainerHelper* pContainer= rBHelper.getContainer( cppu::UnoType<XDropTargetListener>::get());
+    if( pContainer)
+    {
+        OInterfaceIteratorHelper iter( *pContainer );
+        while( iter.hasMoreElements())
+        {
+            Reference<XDropTargetListener> listener( static_cast<XDropTargetListener*>( iter.next()));
+            listener->dragOver( dtde);
+        }
+    }
+}
+
+void DropTarget::fire_dropActionChanged( const DropTargetDragEvent& dtde )
+{
+    OInterfaceContainerHelper* pContainer= rBHelper.getContainer( cppu::UnoType<XDropTargetListener>::get());
+    if( pContainer)
+    {
+        OInterfaceIteratorHelper iter( *pContainer);
+        while( iter.hasMoreElements())
+        {
+            Reference<XDropTargetListener> listener( static_cast<XDropTargetListener*>( iter.next()));
+            listener->dropActionChanged( dtde);
+        }
+    }
+}
+
+// Non - interface functions
+// DropTarget fires events to XDropTargetListeners. The event object contains an
+// XDropTargetDropContext implementation. When the listener calls on that interface
+// then the calls are delegated from DropContext (XDropTargetDropContext) to these
+// functions.
+// Only one listener which visible area is affected is allowed to call on
+// XDropTargetDropContext
+// Returning sal_False would cause the XDropTargetDropContext or ..DragContext implementation
+// to throw an InvalidDNDOperationException, meaning that a Drag is not currently performed.
+// return sal_False results in throwing an InvalidDNDOperationException in the caller.
+
+void DropTarget::_acceptDrop(sal_Int8 dropOperation, const Reference<XDropTargetDropContext>& context)
+{
+    if( context == m_currentDropContext)
+    {
+        m_nCurrentDropAction= dropOperation;
+    }
+}
+
+void DropTarget::_rejectDrop( const Reference<XDropTargetDropContext>& context)
+{
+    if( context == m_currentDropContext)
+    {
+        m_nCurrentDropAction= ACTION_NONE;
+    }
+}
+
+void DropTarget::_dropComplete(bool success, const Reference<XDropTargetDropContext>& context)
+{
+    if(context == m_currentDropContext)
+    {
+        m_bDropComplete= success;
+    }
+}
+
+// DropTarget fires events to XDropTargetListeners. The event object can contains an
+// XDropTargetDragContext implementation. When the listener calls on that interface
+// then the calls are delegated from DragContext (XDropTargetDragContext) to these
+// functions.
+// Only one listener which visible area is affected is allowed to call on
+// XDropTargetDragContext
+void DropTarget::_acceptDrag( sal_Int8 dragOperation, const Reference<XDropTargetDragContext>& context)
+{
+    if( context == m_currentDragContext)
+    {
+        m_nLastDropAction= dragOperation;
+    }
+}
+
+void DropTarget::_rejectDrag( const Reference<XDropTargetDragContext>& context)
+{
+    if(context == m_currentDragContext)
+    {
+        m_nLastDropAction= ACTION_NONE;
+    }
+}
+
+// This function determines the action dependent on the pressed
+// key modifiers ( CTRL, SHIFT, ALT, Right Mouse Button). The result
+// is then checked against the allowed actions which can be set through
+// XDropTarget::setDefaultActions. Only those values which are also
+// default actions are returned. If setDefaultActions has not been called
+// beforehand the default actions comprise all possible actions.
+// params: grfKeyState - the modifier keys and mouse buttons currently pressed
+inline sal_Int8 DropTarget::getFilteredActions( DWORD grfKeyState, DWORD dwEffect)
+{
+    sal_Int8 actions= dndOleKeysToAction( grfKeyState, dndOleDropEffectsToActions( dwEffect));
+    return actions &  m_nDefaultActions;
+}
+
+extern "C" SAL_DLLPUBLIC_EXPORT css::uno::XInterface*
+dtrans_DropTarget_get_implementation(
+    css::uno::XComponentContext* context, css::uno::Sequence<css::uno::Any> const&)
+{
+    return cppu::acquire(new DropTarget(context));
+}
+
+/* vim:set shiftwidth=4 softtabstop=4 expandtab: */