Split serialization.h into common and VST2 parts

src/common/serialization/common.h

@@ -0,0 +1,90 @@
+// 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 <bitsery/traits/string.h>
+
+#include <cstddef>
+#include <cstdint>
+#include <type_traits>
+
+// The plugin should always be compiled to a 64-bit version, but the host
+// application can also be 32-bit to allow using 32-bit legacy Windows VST in a
+// modern Linux VST host. Because of this we have to make sure to always use
+// 64-bit integers in places where we would otherwise use `size_t` and
+// `intptr_t`. Otherwise the binary serialization would break. The 64 <-> 32 bit
+// conversion for the 32-bit host application won't cause any issues for us
+// since we can't directly pass pointers between the plugin and the host anyway.
+
+#ifndef __WINE__
+// Sanity check for the plugin, both the 64 and 32 bit hosts should follow these
+// conventions
+static_assert(std::is_same_v<size_t, uint64_t>);
+static_assert(std::is_same_v<intptr_t, int64_t>);
+#endif
+using native_size_t = uint64_t;
+using native_intptr_t = int64_t;
+
+// The cannonical overloading template for `std::visitor`, not sure why this
+// isn't part of the standard library
+template <class... Ts>
+struct overload : Ts... {
+    using Ts::operator()...;
+};
+template <class... Ts>
+overload(Ts...) -> overload<Ts...>;
+
+/**
+ * An object containing the startup options for hosting a plugin in a plugin
+ * group process. These are the exact same options that would have been passed
+ * to `yabridge-host.exe` were the plugin to be hosted individually.
+ */
+struct GroupRequest {
+    std::string plugin_path;
+    std::string endpoint_base_dir;
+
+    template <typename S>
+    void serialize(S& s) {
+        s.text1b(plugin_path, 4096);
+        s.text1b(endpoint_base_dir, 4096);
+    }
+};
+
+template <>
+struct std::hash<GroupRequest> {
+    std::size_t operator()(GroupRequest const& params) const noexcept {
+        std::hash<string> hasher{};
+
+        return hasher(params.plugin_path) ^
+               (hasher(params.endpoint_base_dir) << 1);
+    }
+};
+
+/**
+ * The response sent back after the group host process receives a `GroupRequest`
+ * object. This only holds the group process's PID because we need to know if
+ * the group process crashes while it is initializing the plugin to prevent us
+ * from waiting indefinitely for the socket to be connected to.
+ */
+struct GroupResponse {
+    pid_t pid;
+
+    template <typename S>
+    void serialize(S& s) {
+        s.value4b(pid);
+    }
+};