Store host pointer in the plugin proxy

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

@@ -85,7 +85,7 @@ clap_plugin_factory_proxy::plugin_factory_create_plugin(
         // correct plugin instance, and callbacks made from the plugin to the
         // correct host instance.
         self->bridge_.register_plugin_proxy(std::make_unique<clap_plugin_proxy>(
-            self->bridge_, *response.instance_id, *descriptor));
+            self->bridge_, *response.instance_id, *descriptor, host));
 
         const auto& [plugin_proxy, _] =
             self->bridge_.get_proxy(*response.instance_id);

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

@@ -20,10 +20,12 @@
 
 clap_plugin_proxy::clap_plugin_proxy(ClapPluginBridge& bridge,
                                      size_t instance_id,
-                                     clap::plugin::Descriptor descriptor)
+                                     clap::plugin::Descriptor descriptor,
+                                     const clap_host_t* host)
     : bridge_(bridge),
       instance_id_(instance_id),
       descriptor_(std::move(descriptor)),
+      host_(host),
       plugin_vtable_(clap_plugin_t{
           .desc = descriptor_.get(),
           .plugin_data = this,

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

@@ -38,7 +38,8 @@ class clap_plugin_proxy {
      */
     clap_plugin_proxy(ClapPluginBridge& bridge,
                       size_t instance_id,
-                      clap::plugin::Descriptor descriptor);
+                      clap::plugin::Descriptor descriptor,
+                      const clap_host_t* host);
 
     clap_plugin_proxy(const clap_plugin_proxy&) = delete;
     clap_plugin_proxy& operator=(const clap_plugin_proxy&) = delete;
@@ -82,6 +83,12 @@ class clap_plugin_proxy {
     size_t instance_id_;
     clap::plugin::Descriptor descriptor_;
 
+    /**
+     * The `clap_host_t*` passed when creating the instance. Any callbacks made
+     * by the proxied plugin instance must go through ere.
+     */
+    const clap_host_t* host_;
+
     /**
      * The vtable for `clap_plugin`, requires that this object is never moved or
      * copied. We'll use the host data pointer instead of placing this vtable at