PluginEntry: enable adding custom factories

to derived classes

Author: Trinitou

include/clap/helpers/plugin-entry.hh

@@ -41,6 +41,11 @@ namespace clap { namespace helpers {
       virtual void deinit() noexcept {}
       virtual const void *getFactory(const char *factoryId) const noexcept { return nullptr; };
       virtual bool enableDraftFactories() const noexcept { return false; }
+      // needed for adding custom factories to a class derived from PluginEntry
+      template <typename T,
+                typename = typename std::enable_if<std::is_base_of<PluginEntry, T>::value &&
+                                                   std::is_default_constructible<T>::value>::type>
+      static const T &getInstance() noexcept;
 
       // clap_plugin_factory
       virtual bool implementsPluginFactory() const noexcept { return false; }

include/clap/helpers/plugin-entry.hxx

@@ -25,6 +25,14 @@ namespace clap { namespace helpers {
       };
    }
 
+   template <MisbehaviourHandler h, CheckingLevel l>
+   template <typename T, typename ValidImpl>
+   const T &PluginEntry<h, l>::getInstance() noexcept {
+      assert(_instance &&
+             "make sure to call this only between plugin_entry.init and plugin_entry.deinit");
+      return *static_cast<const T *>(_instance.get());
+   }
+
    template <MisbehaviourHandler h, CheckingLevel l>
    int32_t PluginEntry<h, l>::getPluginIndexForPluginId(const char *pluginId) const noexcept {
       const auto count = pluginFactoryGetPluginCount();