propsys: Implement VariantToStringWithDefault.

dlls/propsys/propsys.spec

@@ -194,7 +194,7 @@
 @ stub VariantToStringAlloc
 @ stub VariantToStringArray
 @ stub VariantToStringArrayAlloc
-@ stub VariantToStringWithDefault
+@ stdcall VariantToStringWithDefault(ptr wstr)
 @ stub VariantToUInt16
 @ stub VariantToUInt16Array
 @ stub VariantToUInt16ArrayAlloc

dlls/propsys/propvar.c

@@ -416,6 +416,22 @@ PCWSTR WINAPI PropVariantToStringWithDefault(REFPROPVARIANT propvarIn, LPCWSTR p
     return pszDefault;
 }
 
+/******************************************************************
+ *  VariantToStringWithDefault   (PROPSYS.@)
+ */
+PCWSTR WINAPI VariantToStringWithDefault(const VARIANT *pvar, const WCHAR *default_value)
+{
+    TRACE("%s, %s.\n", debugstr_variant(pvar), debugstr_w(default_value));
+
+    if (V_VT(pvar) == (VT_BYREF | VT_VARIANT)) pvar = V_VARIANTREF(pvar);
+    if (V_VT(pvar) == (VT_BYREF | VT_BSTR) || V_VT(pvar) == VT_BSTR)
+    {
+        BSTR ret = V_ISBYREF(pvar) ? *V_BSTRREF(pvar) : V_BSTR(pvar);
+        return ret ? ret : L"";
+    }
+
+    return default_value;
+}
 
 /******************************************************************
  *  PropVariantChangeType   (PROPSYS.@)

include/propvarutil.h

@@ -93,6 +93,7 @@ HRESULT WINAPI PropVariantToBoolean(REFPROPVARIANT propvarIn, BOOL *ret);
 HRESULT WINAPI PropVariantToBuffer(REFPROPVARIANT propvarIn, void *ret, UINT cb);
 HRESULT WINAPI PropVariantToString(REFPROPVARIANT propvarIn, PWSTR ret, UINT cch);
 PCWSTR WINAPI PropVariantToStringWithDefault(REFPROPVARIANT propvarIn, LPCWSTR pszDefault);
+PCWSTR WINAPI VariantToStringWithDefault(const VARIANT *pvar, LPCWSTR pszDefault);
 
 HRESULT WINAPI PropVariantToStringAlloc(REFPROPVARIANT propvarIn, WCHAR **ret);