Fix exclude-only C++/WinRT module filtering

cppwinrt/settings.h

@@ -2,6 +2,46 @@
 
 namespace cppwinrt
 {
+    struct module_filter_type
+    {
+        module_filter_type() = default;
+
+        module_filter_type(std::set<std::string> const& include, std::set<std::string> const& exclude) :
+            m_has_include(!include.empty()),
+            m_has_exclude(!exclude.empty()),
+            m_include_filter{ include, exclude },
+            m_exclude_filter{ exclude, {} }
+        {
+        }
+
+        bool empty() const noexcept
+        {
+            return !m_has_include && !m_has_exclude;
+        }
+
+        template <typename T>
+        bool includes(T const& value) const
+        {
+            if (m_has_include)
+            {
+                return m_include_filter.includes(value);
+            }
+
+            if (m_has_exclude)
+            {
+                return !m_exclude_filter.includes(value);
+            }
+
+            return true;
+        }
+
+    private:
+        bool m_has_include{};
+        bool m_has_exclude{};
+        winmd::reader::filter m_include_filter;
+        winmd::reader::filter m_exclude_filter;
+    };
+
     struct settings_type
     {
         std::set<std::string> input;
@@ -36,7 +76,7 @@ namespace cppwinrt
 
         std::set<std::string> module_include;
         std::set<std::string> module_exclude;
-        winmd::reader::filter module_filter;
+        module_filter_type module_filter;
     };
 
     extern settings_type settings;