Store plugin and host extension struct pointers

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

@@ -18,6 +18,12 @@
 
 #include "../clap.h"
 
+ClapHostExtensions::ClapHostExtensions(const clap_host& host) noexcept
+    : audio_ports(static_cast<const clap_host_audio_ports_t*>(
+          host.get_extension(&host, CLAP_EXT_AUDIO_PORTS))) {}
+
+ClapHostExtensions::ClapHostExtensions() noexcept {}
+
 clap_plugin_proxy::clap_plugin_proxy(ClapPluginBridge& bridge,
                                      size_t instance_id,
                                      clap::plugin::Descriptor descriptor,
@@ -52,6 +58,12 @@ bool CLAP_ABI clap_plugin_proxy::plugin_init(const struct clap_plugin* plugin) {
     assert(plugin && plugin->plugin_data);
     auto self = static_cast<clap_plugin_proxy*>(plugin->plugin_data);
 
+    // At this point we are allowed to query the host for extension structs.
+    // We'll store pointers to the host's extensions vtables, and then send
+    // whether or not those extensions were supported as booleans to the Wine
+    // plugin host so it can expose the same interfaces there.
+    self->extensions_ = ClapHostExtensions(*self->host_);
+
     const clap::plugin::InitResponse response =
         self->bridge_.send_main_thread_message(
             clap::plugin::Init{.instance_id = self->instance_id(),

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

@@ -29,6 +29,29 @@
 // Forward declaration to avoid circular includes
 class ClapPluginBridge;
 
+/**
+ * Pointers to all of a CLAP host's extension structs. These will be null if the
+ * host doesn't support the extensions.
+ *
+ * @relates clap_plugin_proxy
+ */
+struct ClapHostExtensions {
+    /**
+     * Query all of the host's extensions. This can only be done after the
+     * call to init.
+     */
+    ClapHostExtensions(const clap_host& host) noexcept;
+
+    /**
+     * The default constructor that assumes the host doesn't support any
+     * extensions. We may only query the extensions after the plugin has called
+     * `clap_plugin::init()`.
+     */
+    ClapHostExtensions() noexcept;
+
+    const clap_host_audio_ports_t* audio_ports = nullptr;
+};
+
 /**
  * A proxy for a `clap_plugin`.
  */
@@ -131,10 +154,16 @@ class clap_plugin_proxy {
 
     /**
      * The `clap_host_t*` passed when creating the instance. Any callbacks made
-     * by the proxied plugin instance must go through ere.
+     * by the proxied plugin instance must go through here.
      */
     const clap_host_t* host_;
 
+    /**
+     * The host's supported extensions. These will be populated in the
+     * `clap_plugin::init()` call.
+     */
+    ClapHostExtensions extensions_;
+
    private:
     ClapPluginBridge& bridge_;
     size_t instance_id_;