Handle exceptions in user drop targets code in wxMSW

All exceptions thrown by wxDropTarget::OnXXX() must be caught and handled in
the same way as we already do it for the exceptions in the event handlers as
we can't let the exceptions escape into system/kernel code: while it can work
in some cases, it doesn't work in general, e.g. exceptions simply disappear
when they happen in 32 bit programs under 64 bit Windows 7.

src/msw/ole/droptgt.cpp

@@ -27,6 +27,7 @@
 
 #ifndef WX_PRECOMP
     #include "wx/msw/wrapwin.h"
+    #include "wx/except.h"
     #include "wx/log.h"
 #endif
 
@@ -180,6 +181,8 @@ STDMETHODIMP wxIDropTarget::DragEnter(IDataObject *pIDataSource,
                                       DWORD        grfKeyState,
                                       POINTL       pt,
                                       DWORD       *pdwEffect)
+{
+    wxTRY
     {
         wxLogTrace(wxTRACE_OleCalls, wxT("IDropTarget::DragEnter"));
 
@@ -244,6 +247,8 @@ STDMETHODIMP wxIDropTarget::DragEnter(IDataObject *pIDataSource,
 
         return S_OK;
     }
+    wxCATCH_ALL( wxEvtHandler::WXConsumeException(); return E_UNEXPECTED; )
+}
 
 
 
@@ -259,6 +264,8 @@ STDMETHODIMP wxIDropTarget::DragEnter(IDataObject *pIDataSource,
 STDMETHODIMP wxIDropTarget::DragOver(DWORD   grfKeyState,
                                      POINTL  pt,
                                      LPDWORD pdwEffect)
+{
+    wxTRY
     {
         // there are too many of them... wxLogDebug("IDropTarget::DragOver");
 
@@ -293,12 +300,16 @@ STDMETHODIMP wxIDropTarget::DragOver(DWORD   grfKeyState,
 
         return S_OK;
     }
+    wxCATCH_ALL( wxEvtHandler::WXConsumeException(); return E_UNEXPECTED; )
+}
 
 // Name    : wxIDropTarget::DragLeave
 // Purpose : Informs the drop target that the operation has left its window.
 // Returns : S_OK
 // Notes   : good place to do any clean-up
 STDMETHODIMP wxIDropTarget::DragLeave()
+{
+    wxTRY
     {
         wxLogTrace(wxTRACE_OleCalls, wxT("IDropTarget::DragLeave"));
 
@@ -313,6 +324,8 @@ STDMETHODIMP wxIDropTarget::DragLeave()
 
         return S_OK;
     }
+    wxCATCH_ALL( wxEvtHandler::WXConsumeException(); return E_UNEXPECTED; )
+}
 
 // Name    : wxIDropTarget::Drop
 // Purpose : Instructs the drop target to paste data that was just now
@@ -327,6 +340,8 @@ STDMETHODIMP wxIDropTarget::Drop(IDataObject *pIDataSource,
                                  DWORD        grfKeyState,
                                  POINTL       pt,
                                  DWORD       *pdwEffect)
+{
+    wxTRY
     {
         wxLogTrace(wxTRACE_OleCalls, wxT("IDropTarget::Drop"));
 
@@ -371,6 +386,8 @@ STDMETHODIMP wxIDropTarget::Drop(IDataObject *pIDataSource,
 
         return S_OK;
     }
+    wxCATCH_ALL( wxEvtHandler::WXConsumeException(); return E_UNEXPECTED; )
+}
 
 // ============================================================================
 // wxDropTarget implementation