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
 
@@ -181,6 +182,8 @@ STDMETHODIMP wxIDropTarget::DragEnter(IDataObject *pIDataSource,
                                       POINTL       pt,
                                       DWORD       *pdwEffect)
 {
+    wxTRY
+    {
         wxLogTrace(wxTRACE_OleCalls, wxT("IDropTarget::DragEnter"));
 
         wxASSERT_MSG( m_pIDataObject == NULL,
@@ -243,6 +246,8 @@ STDMETHODIMP wxIDropTarget::DragEnter(IDataObject *pIDataSource,
         m_pTarget->MSWUpdateDragImageOnDragOver(pt.x, pt.y, res);
 
         return S_OK;
+    }
+    wxCATCH_ALL( wxEvtHandler::WXConsumeException(); return E_UNEXPECTED; )
 }
 
 
@@ -260,6 +265,8 @@ STDMETHODIMP wxIDropTarget::DragOver(DWORD   grfKeyState,
                                      POINTL  pt,
                                      LPDWORD pdwEffect)
 {
+    wxTRY
+    {
         // there are too many of them... wxLogDebug("IDropTarget::DragOver");
 
         wxDragResult result;
@@ -292,6 +299,8 @@ STDMETHODIMP wxIDropTarget::DragOver(DWORD   grfKeyState,
                                                 ConvertDragEffectToResult(*pdwEffect));
 
         return S_OK;
+    }
+    wxCATCH_ALL( wxEvtHandler::WXConsumeException(); return E_UNEXPECTED; )
 }
 
 // Name    : wxIDropTarget::DragLeave
@@ -300,6 +309,8 @@ STDMETHODIMP wxIDropTarget::DragOver(DWORD   grfKeyState,
 // Notes   : good place to do any clean-up
 STDMETHODIMP wxIDropTarget::DragLeave()
 {
+    wxTRY
+    {
         wxLogTrace(wxTRACE_OleCalls, wxT("IDropTarget::DragLeave"));
 
         // remove the UI feedback
@@ -312,6 +323,8 @@ STDMETHODIMP wxIDropTarget::DragLeave()
         m_pTarget->MSWUpdateDragImageOnLeave();
 
         return S_OK;
+    }
+    wxCATCH_ALL( wxEvtHandler::WXConsumeException(); return E_UNEXPECTED; )
 }
 
 // Name    : wxIDropTarget::Drop
@@ -328,6 +341,8 @@ STDMETHODIMP wxIDropTarget::Drop(IDataObject *pIDataSource,
                                  POINTL       pt,
                                  DWORD       *pdwEffect)
 {
+    wxTRY
+    {
         wxLogTrace(wxTRACE_OleCalls, wxT("IDropTarget::Drop"));
 
         // TODO I don't know why there is this parameter, but so far I assume
@@ -370,6 +385,8 @@ STDMETHODIMP wxIDropTarget::Drop(IDataObject *pIDataSource,
                                             ConvertDragEffectToResult(*pdwEffect));
 
         return S_OK;
+    }
+    wxCATCH_ALL( wxEvtHandler::WXConsumeException(); return E_UNEXPECTED; )
 }
 
 // ============================================================================