Move AEffect updating to a function

src/common/events.h

@@ -313,23 +313,7 @@ auto passthrough_event(AEffect* plugin, F callback) {
                 // return value, we will update values on the native VST
                 // plugin's `AEffect` object. This is triggered by the
                 // `audioMasterIOChanged` callback from the hosted VST plugin.
-
+                update_aeffect(*plugin, updated_plugin);
-                // These are the same fields written by bitsery in the
-                // initialization of `PluginBridge`. I can't think of a way to
-                // reuse the serializer without first having to serialize
-                // `updated_plugin` first though.
-                plugin->magic = updated_plugin.magic;
-                plugin->numPrograms = updated_plugin.numPrograms;
-                plugin->numParams = updated_plugin.numParams;
-                plugin->numInputs = updated_plugin.numInputs;
-                plugin->numOutputs = updated_plugin.numOutputs;
-                plugin->flags = updated_plugin.flags;
-                plugin->initialDelay = updated_plugin.initialDelay;
-                plugin->empty3a = updated_plugin.empty3a;
-                plugin->empty3b = updated_plugin.empty3b;
-                plugin->unkown_float = updated_plugin.unkown_float;
-                plugin->uniqueID = updated_plugin.uniqueID;
-                plugin->version = updated_plugin.version;
 
                 return nullptr;
             },

src/common/serialization.cpp

@@ -91,3 +91,20 @@ std::vector<uint8_t>& DynamicSpeakerArrangement::as_raw_data() {
 
     return speaker_arrangement_buffer;
 }
+
+AEffect& update_aeffect(AEffect& plugin, const AEffect& updated_plugin) {
+    plugin.magic = updated_plugin.magic;
+    plugin.numPrograms = updated_plugin.numPrograms;
+    plugin.numParams = updated_plugin.numParams;
+    plugin.numInputs = updated_plugin.numInputs;
+    plugin.numOutputs = updated_plugin.numOutputs;
+    plugin.flags = updated_plugin.flags;
+    plugin.initialDelay = updated_plugin.initialDelay;
+    plugin.empty3a = updated_plugin.empty3a;
+    plugin.empty3b = updated_plugin.empty3b;
+    plugin.unkown_float = updated_plugin.unkown_float;
+    plugin.uniqueID = updated_plugin.uniqueID;
+    plugin.version = updated_plugin.version;
+
+    return plugin;
+}

src/common/serialization.h

@@ -85,10 +85,21 @@ struct overload : Ts... {
 template <class... Ts>
 overload(Ts...) -> overload<Ts...>;
 
+/**
+ * Update an `AEffect` object, copying values from `updated_plugin` to `plugin`.
+ * This will copy all flags and regular values, leaving all pointers in `plugin`
+ * untouched. This should be updating the same values as the serialization
+ * function right below this.
+ */
+AEffect& update_aeffect(AEffect& plugin, const AEffect& updated_plugin);
+
 /**
  * The serialization function for `AEffect` structs. This will s serialize all
  * of the values but it will not touch any of the pointer fields. That way you
- * can deserialize to an existing `AEffect` instance.
+ * can deserialize to an existing `AEffect` instance. Since we can't always
+ * deserialize directly into an existing `AEffect`, there is also another
+ * function called `update_aeffect()` that copies values from one `AEffect` to
+ * another. Both of these functions should be updating the same values.
  */
 template <typename S>
 void serialize(S& s, AEffect& plugin) {