Split up a ConstructArgs from YaContextMenuTarget

So we can send this as a payload when the plugin adds a context menu
item.

src/common/serialization/vst3/context-menu-target.cpp

@@ -16,12 +16,16 @@
 
 #include "context-menu-target.h"
 
-YaContextMenuTarget::YaContextMenuTarget(native_size_t owner_instance_id,
+YaContextMenuTarget::ConstructArgs::ConstructArgs(
-                                         native_size_t context_menu_id,
+    native_size_t owner_instance_id,
-                                         int32 tag)
+    native_size_t context_menu_id,
+    int32 tag)
     : owner_instance_id(owner_instance_id),
       context_menu_id(context_menu_id),
-      tag(tag){FUNKNOWN_CTOR}
+      tag(tag) {}
+
+YaContextMenuTarget::YaContextMenuTarget(const ConstructArgs&& args)
+    : arguments(std::move(args)){FUNKNOWN_CTOR}
 
       YaContextMenuTarget::~YaContextMenuTarget() {
     FUNKNOWN_DTOR

src/common/serialization/vst3/context-menu-target.h

@@ -32,19 +32,44 @@
  */
 class YaContextMenuTarget : public Steinberg::Vst::IContextMenuTarget {
    public:
+    /**
+     * These are the arguments for constructing a
+     * `YaContextMenuTargetImpl`.
+     */
+    struct ConstructArgs {
+        ConstructArgs();
+
+        /**
+         * Read from an existing object. We will try to mimic this object, so
+         * we'll support any interfaces this object also supports.
+         *
+         * @param owner_instance_id The object instance that this target's
+         * context menu belongs to.
+         * @param context_menu_id The unique ID of the context menu requested by
+         *   `owwner_instance_id`.
+         * @param tag The tag of the menu item this target belongs to.
+         */
+        ConstructArgs(native_size_t owner_instance_id,
+                      native_size_t context_menu_id,
+                      int32 tag);
+
+        native_size_t owner_instance_id;
+        native_size_t context_menu_id;
+        int32 tag;
+
+        template <typename S>
+        void serialize(S& s) {
+            s.value8b(owner_instance_id);
+            s.value8b(context_menu_id);
+            s.value4b(tag);
+        }
+    };
+
     /**
      * Create context menu target that when called, calls the corresponding
      * context menu target provided by the object.
-     *
-     * @param owner_instance_id The object instance that this target's context
-     *   menu belongs to.
-     * @param context_menu_id The unique ID of the context menu requested by
-     *   `owwner_instance_id`.
-     * @param tag The tag of the menu item this target belongs to.
      */
-    YaContextMenuTarget(native_size_t owner_instance_id,
+    YaContextMenuTarget(const ConstructArgs&& args);
-                        native_size_t context_menu_id,
-                        int32 tag);
 
     ~YaContextMenuTarget();
 
@@ -53,9 +78,7 @@ class YaContextMenuTarget : public Steinberg::Vst::IContextMenuTarget {
     virtual tresult PLUGIN_API executeMenuItem(int32 tag) override = 0;
 
    protected:
-    native_size_t owner_instance_id;
+    ConstructArgs arguments;
-    native_size_t context_menu_id;
-    int32 tag;
 };
 
 #pragma GCC diagnostic pop

src/plugin/bridges/vst3-impls/context-menu-target.cpp

@@ -16,13 +16,9 @@
 
 #include "context-menu-target.h"
 
-YaContextMenuTargetImpl::YaContextMenuTargetImpl(
+YaContextMenuTargetImpl::YaContextMenuTargetImpl(Vst3PluginBridge& bridge,
-    Vst3PluginBridge& bridge,
+                                                 const ConstructArgs&& args)
-    native_size_t owner_instance_id,
+    : YaContextMenuTarget(std::move(args)), bridge(bridge) {}
-    native_size_t context_menu_id,
-    int32 tag)
-    : YaContextMenuTarget(owner_instance_id, context_menu_id, tag),
-      bridge(bridge) {}
 
 tresult PLUGIN_API
 YaContextMenuTargetImpl::queryInterface(const Steinberg::TUID _iid,

src/plugin/bridges/vst3-impls/context-menu-target.h

@@ -20,13 +20,8 @@
 
 class YaContextMenuTargetImpl : public YaContextMenuTarget {
    public:
-    /**
-     * @override
-     */
     YaContextMenuTargetImpl(Vst3PluginBridge& bridge,
-                            native_size_t owner_instance_id,
+                            const ConstructArgs&& args);
-                            native_size_t context_menu_id,
-                            int32 tag);
 
     /**
      * We'll override the query interface to log queries for interfaces we do