From db1a51af5c6b33e06579af0a1216299d40fce74a Mon Sep 17 00:00:00 2001
From: Robbert van der Helm <mail@robbertvanderhelm.nl>
Date: Fri, 4 Dec 2020 14:59:46 +0100
Subject: [PATCH] Add serialization primitives for VST3

---
 src/common/serialization/vst2.h |   4 +-
 src/common/serialization/vst3.h | 100 ++++++++++++++++++++++++++++++++
 2 files changed, 102 insertions(+), 2 deletions(-)
 create mode 100644 src/common/serialization/vst3.h

diff --git a/src/common/serialization/vst2.h b/src/common/serialization/vst2.h
index ada95336..16766edd 100644
--- a/src/common/serialization/vst2.h
+++ b/src/common/serialization/vst2.h
@@ -16,14 +16,14 @@
 
 #pragma once
 
+#include <variant>
+
 #include <bitsery/ext/std_optional.h>
 #include <bitsery/ext/std_variant.h>
 #include <bitsery/traits/array.h>
 #include <bitsery/traits/vector.h>
 #include <vestige/aeffectx.h>
 
-#include <variant>
-
 #include "../vst24.h"
 #include "common.h"
 
diff --git a/src/common/serialization/vst3.h b/src/common/serialization/vst3.h
new file mode 100644
index 00000000..3267de2b
--- /dev/null
+++ b/src/common/serialization/vst3.h
@@ -0,0 +1,100 @@
+// yabridge: a Wine VST bridge
+// Copyright (C) 2020  Robbert van der Helm
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+#pragma once
+
+#include <variant>
+
+#include <bitsery/ext/std_variant.h>
+
+#include "../configuration.h"
+#include "common.h"
+
+// Event handling for our VST3 plugins works slightly different from how we
+// handle VST2 plugins. VST3 does not have a centralized event dispatching
+// interface like VST2 does, and it uses a bunch of separate interfaces instead.
+// Instead of having an a single event/result with accompanying payload values
+// for both host -> plugin `dispatcher()` and plugin -> host `audioMaster()`
+// calls, we'll just send request and response payloads directly without any
+// metadata. We also split everything up into host -> plugin 'control' payloads
+// and plugin -> host 'callback' payloads for maintainability's sake.
+
+// TODO: If this approach works, maybe we can also refactor the VST2 handling to
+//       do this since it's a bit safer and easier to read
+
+/**
+ * Marker struct to indicate the other side (the plugin) should send a copy of
+ * the configuration.
+ */
+struct WantsConfiguration {
+    using Response = Configuration;
+};
+
+/**
+ * When we send a control message from the plugin to the Wine VST host, this
+ * encodes the information we request or the operation we want to perform. A
+ * request of type `T` should send back a `CallbackResponse` containing
+ * `T::Reponse`.
+ *
+ * @relates ControlResponse
+ */
+using ControlRequest = std::variant<>;
+
+template <typename S>
+void serialize(S& s, ControlRequest& payload) {
+    s.ext(payload, bitsery::ext::StdVariant{});
+}
+
+/**
+ * A response to a control message. Tee `T::Reponse` for the correct type to
+ * return here.
+ *
+ * @relates ControlRrequest
+ */
+using ControlResponse = std::variant<>;
+
+template <typename S>
+void serialize(S& s, ControlResponse& payload) {
+    s.ext(payload, bitsery::ext::StdVariant{});
+}
+
+/**
+ * When we do a callback from the Wine VST host to the plugin, this encodes the
+ * information we want or the operation we want to perform. A request of type
+ * `T` should send back a `CallbackResponse` containing `T::Reponse`.
+ *
+ * @relates CallbackResponse
+ */
+using CallbackRequest = std::variant<WantsConfiguration>;
+
+template <typename S>
+void serialize(S& s, CallbackRequest& payload) {
+    s.ext(payload, bitsery::ext::StdVariant{[](S&, WantsConfiguration&) {}});
+}
+
+/**
+ * A response to a callback. Tee `T::Reponse` for the correct type to return
+ * here.
+ *
+ * @relates CallbackRrequest
+ */
+using CallbackResponse = std::variant<Configuration>;
+
+template <typename S>
+void serialize(S& s, CallbackResponse& payload) {
+    s.ext(payload, bitsery::ext::StdVariant{
+                       [](S& s, Configuration& config) { s.object(config); }});
+}