Add CLAP plugin destroying

Everything else is still a stub, but at least the lifecycle now works
correctly.

src/common/logging/clap.cpp

@@ -38,16 +38,22 @@ bool ClapLogger::log_request(bool is_host_plugin,
     });
 }
 
+bool ClapLogger::log_request(bool is_host_plugin,
+                             const clap::plugin::Destroy& request) {
+    return log_request_base(is_host_plugin, [&](auto& message) {
+        message << request.instance_id << ": clap_plugin::destroy()";
+    });
+}
+
 bool ClapLogger::log_request(bool is_host_plugin, const WantsConfiguration&) {
     return log_request_base(is_host_plugin, [&](auto& message) {
         message << "Requesting <Configuration>";
     });
 }
 
-// void ClapLogger::log_response(bool is_host_plugin, const Ack&) {
+void ClapLogger::log_response(bool is_host_plugin, const Ack&) {
-//     log_response_base(is_host_plugin, [&](auto& message) { message << "ACK";
+    log_response_base(is_host_plugin, [&](auto& message) { message << "ACK"; });
-//     });
+}
-// }
 
 void ClapLogger::log_response(
     bool is_host_plugin,

src/common/logging/clap.h

@@ -47,6 +47,7 @@ class ClapLogger {
 
     bool log_request(bool is_host_plugin, const clap::plugin_factory::List&);
     bool log_request(bool is_host_plugin, const clap::plugin_factory::Create&);
+    bool log_request(bool is_host_plugin, const clap::plugin::Destroy&);
 
     // TODO: Audio thread requests
     // bool log_request(bool is_host_plugin,
@@ -54,7 +55,7 @@ class ClapLogger {
 
     bool log_request(bool is_host_plugin, const WantsConfiguration&);
 
-    // void log_response(bool is_host_plugin, const Ack&);
+    void log_response(bool is_host_plugin, const Ack&);
     void log_response(bool is_host_plugin,
                       const clap::plugin_factory::ListResponse&);
     void log_response(bool is_host_plugin,

src/common/serialization/clap.h

@@ -41,7 +41,8 @@
 //        serialize this without it.
 using ClapMainThreadControlRequest = std::variant<WantsConfiguration,
                                                   clap::plugin_factory::List,
-                                                  clap::plugin_factory::Create>;
+                                                  clap::plugin_factory::Create,
+                                                  clap::plugin::Destroy>;
 
 template <typename S>
 void serialize(S& s, ClapMainThreadControlRequest& payload) {

src/common/serialization/clap/plugin.h

@@ -24,6 +24,7 @@
 #include <clap/plugin.h>
 
 #include "../../bitsery/ext/in-place-optional.h"
+#include "../common.h"
 
 // Serialization messages for `clap/plugin.h`
 
@@ -104,6 +105,22 @@ struct Descriptor {
     mutable clap_plugin_descriptor_t clap_descriptor;
 };
 
+/**
+ * Message struct for `clap_plugin::destroy()`. The Wine plugin host should
+ * clean up the plugin, and everything is also cleaned up on the plugin side
+ * after receiving acknowledgement
+ */
+struct Destroy {
+    using Response = Ack;
+
+    native_size_t instance_id;
+
+    template <typename S>
+    void serialize(S& s) {
+        s.value8b(instance_id);
+    }
+};
+
 }  // namespace plugin
 }  // namespace clap
 

src/plugin/bridges/clap-impls/plugin-proxy.cpp

@@ -54,9 +54,12 @@ clap_plugin_proxy::plugin_destroy(const struct clap_plugin* plugin) {
     assert(plugin && plugin->plugin_data);
     auto self = static_cast<const clap_plugin_proxy*>(plugin->plugin_data);
 
-    // TODO: Destroy on the Wine side
+    // This will clean everything related to this instance up on the Wine plugin
+    // host side
+    self->bridge_.send_main_thread_message(
+        clap::plugin::Destroy{.instance_id = self->instance_id()});
 
-    // This deallocates and destroys `self`
+    // And this deallocates and destroys `self`
     self->bridge_.unregister_plugin_proxy(self->instance_id());
 }
 

src/wine-host/bridges/clap.cpp

@@ -209,6 +209,19 @@ void ClapBridge::run() {
                     })
                     .get();
             },
+            [&](clap::plugin::Destroy& request)
+                -> clap::plugin::Destroy::Response {
+                return main_context_
+                    .run_in_context([&]() {
+                        // This calls `clap_plugin::destroy()` as part of
+                        // cleaning up the `unique_ptr` holding the plugin
+                        // instance pointer
+                        unregister_plugin_instance(request.instance_id);
+
+                        return Ack{};
+                    })
+                    .get();
+            },
         });
 }
 
@@ -446,12 +459,8 @@ void ClapBridge::unregister_plugin_instance(size_t instance_id) {
 
     // Remove the instance from within the main IO context so
     // removing it doesn't interfere with the Win32 message loop
-    // XXX: I don't think we have to wait for the object to be
+    // NOTE: This will implicitly run `clap_plugin::destroy()` as part of the
-    //      deleted most of the time, but I can imagine a situation
+    //       `unique_ptr`'s cleanup
-    //      where the plugin does a host callback triggered by a
-    //      Win32 timer in between where the above closure is being
-    //      executed and when the actual host application context on
-    //      the plugin side gets deallocated.
     main_context_
         .run_in_context([&, instance_id]() -> void {
             std::unique_lock lock(object_instances_mutex_);