[1/4] msxml3: Added common ISupportErrorInfo implementation

[Jacek Caban]

Hi Nikolay,

On 11/21/11 08:24, Nikolay Sivov wrote:
>   Added common ISupportErrorInfo implementation

+/* common ISupportErrorInfo implementation */
+typedef struct {
+   ISupportErrorInfo ISupportErrorInfo_iface;
+   LONG ref;
+
+   const tid_t* iids;
+} SupportErrorInfo;
+
+static inline SupportErrorInfo *impl_from_ISupportErrorInfo(ISupportErrorInfo *iface)
+{
+    return CONTAINING_RECORD(iface, SupportErrorInfo, ISupportErrorInfo_iface);
+}
+
+static HRESULT WINAPI SupportErrorInfo_QueryInterface(ISupportErrorInfo *iface, REFIID riid, void **obj)
+{
+    SupportErrorInfo *This = impl_from_ISupportErrorInfo(iface);
+    TRACE("(%p)->(%s %p)\n", This, debugstr_guid(riid), obj);
+
+    *obj = NULL;
+
+    if (IsEqualGUID(riid,&IID_IUnknown) || IsEqualGUID(riid,&IID_ISupportErrorInfo)) {
+        *obj = iface;
+        ISupportErrorInfo_AddRef(iface);
+        return S_OK;
+    }
+
+    return E_NOINTERFACE;
+}



This doesn't seem to be the right approach. You need to return here 
interfaces of an object that inherits your ISupportErrorInfo 
implementation - that's the COM rule. Also you probably don't want to 
create new SupportErrorInfo instance on each QI call. I'd suggest 
DispatchEx-like approach in this case (or even abuse DispatchEx object 
and add ISupportErrorInfo there).

Jacek