[PATCH v3 1/1] shell32: Create an internal IDropSource in SHDoDragDrop if it wasn't passed by the caller

[Lorenzo Ferrillo]

From: Lorenzo Ferrillo

---
 dlls/shell32/shellord.c | 108 +++++++++++++++++++++++++++++++++++++++-
 1 file changed, 106 insertions(+), 2 deletions(-)

diff --git a/dlls/shell32/shellord.c b/dlls/shell32/shellord.c
index a007c0e5c60..7c262e6436f 100644
--- a/dlls/shell32/shellord.c
+++ b/dlls/shell32/shellord.c
@@ -534,6 +534,90 @@ HRESULT WINAPI SHRevokeDragDrop(HWND hWnd)
     return RevokeDragDrop(hWnd);
 }

+
+typedef struct InternalDropSource{
+    IDropSource       IDropSource_iface;
+    LONG Ref;
+} InternalDropSource;
+
+static inline InternalDropSource *impl_from_IDropSource(IDropSource *iface)
+{
+    return CONTAINING_RECORD(iface, InternalDropSource, IDropSource_iface);
+}
+
+static HRESULT WINAPI InternalDropSource_QueryInterface(IDropSource *iface, REFIID riid, void **ppvObj)
+{
+    InternalDropSource *This = impl_from_IDropSource(iface);
+    TRACE("(%p)->(%s, %p)\n", This, debugstr_guid(riid), ppvObj);
+
+    *ppvObj = NULL;
+
+    if(IsEqualIID(riid, &IID_IDropSource)  || IsEqualIID(riid, &IID_IUnknown) )
+    {
+        *ppvObj = &This->IDropSource_iface;
+        IUnknown_AddRef ((IUnknown *) (*ppvObj));
+        TRACE("-- Interface: (%p)->(%p)\n",ppvObj,*ppvObj);
+        return S_OK;
+    }
+
+    WARN("-- Interface: E_NOINTERFACE\n");
+    return E_NOINTERFACE;
+}
+
+static ULONG WINAPI InternalDropSource_AddRef(IDropSource *iface)
+{
+    InternalDropSource *This = impl_from_IDropSource(iface);
+    TRACE("(%p)->(%lu)\n", This, This->Ref);
+    return InterlockedIncrement(&This->Ref);
+}
+
+static ULONG WINAPI InternalDropSource_Release(IDropSource *iface)
+{
+    ULONG refcount;
+    InternalDropSource *This = impl_from_IDropSource(iface);
+    TRACE("(%p)->(%lu)\n", This, This->Ref);
+    refcount =  InterlockedDecrement(&This->Ref);
+
+    if(refcount == 0)
+        free(This);
+
+    return refcount;
+}
+
+static HRESULT WINAPI InternalDropSource_QueryContinueDrag(
+    IDropSource *iface,
+    BOOL fEscapePressed,
+    DWORD grfKeyState)
+{
+    InternalDropSource *This = impl_from_IDropSource(iface);
+    TRACE("(%p)\n",This);
+
+    if (fEscapePressed)
+        return DRAGDROP_S_CANCEL;
+    else if (!(grfKeyState & MK_LBUTTON) && !(grfKeyState & MK_RBUTTON))
+        return DRAGDROP_S_DROP;
+    else
+        return S_OK;
+}
+
+static HRESULT WINAPI InternalDropSource_GiveFeedback(
+    IDropSource *iface,
+    DWORD dwEffect)
+{
+    InternalDropSource *This = impl_from_IDropSource(iface);
+    TRACE("(%p)\n",This);
+
+    return DRAGDROP_S_USEDEFAULTCURSORS;
+}
+
+static const IDropSourceVtbl dropsourcevtbl =
+{
+    InternalDropSource_QueryInterface,
+    InternalDropSource_AddRef,
+    InternalDropSource_Release,
+    InternalDropSource_QueryContinueDrag,
+    InternalDropSource_GiveFeedback
+};
 /*************************************************************************
  * SHDoDragDrop					[SHELL32.88]
  *
@@ -554,9 +638,29 @@ HRESULT WINAPI SHDoDragDrop(
    DWORD dwOKEffect,
    LPDWORD pdwEffect)
 {
+    HRESULT hr;
+    LPDROPSOURCE dropSource = lpDropSource;
     FIXME("(%p %p %p 0x%08lx %p):stub.\n",
-    hWnd, lpDataObject, lpDropSource, dwOKEffect, pdwEffect);
-	return DoDragDrop(lpDataObject, lpDropSource, dwOKEffect, pdwEffect);
+          hWnd, lpDataObject, lpDropSource, dwOKEffect, pdwEffect);
+    if(lpDropSource == NULL)
+    {
+        /*This function should create a IDropSource object if the lpDropSource parameter was NULL.
+         * Delphi's drag and drop functions expect this to work when it detects Windows Vista or above */
+       InternalDropSource*  dummy = calloc(1, sizeof(InternalDropSource));
+       if(!dummy)
+           return E_OUTOFMEMORY;
+
+       dummy->IDropSource_iface.lpVtbl = &dropsourcevtbl;
+       dummy->Ref = 1;
+       dropSource = &dummy->IDropSource_iface;
+    }
+    hr = DoDragDrop(lpDataObject, dropSource, dwOKEffect, pdwEffect);
+    if(lpDropSource == NULL)
+    {
+        /*Source was created internally, free*/
+        InternalDropSource_Release(dropSource);
+    }
+    return hr;
 }

/*************************************************************************