Add stubs for plugin side audio ports extension

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

@@ -40,6 +40,10 @@ clap_plugin_proxy::clap_plugin_proxy(ClapPluginBridge& bridge,
           .get_extension = plugin_get_extension,
           .on_main_thread = plugin_on_main_thread,
       }),
+      ext_audio_ports_vtable(clap_plugin_audio_ports_t{
+          .count = ext_audio_ports_count,
+          .get = ext_audio_ports_get,
+      }),
       // These function objects are relatively large, and we probably won't be
       // getting that many of them
       pending_callbacks_(128) {}
@@ -146,15 +150,18 @@ clap_plugin_proxy::plugin_process(const struct clap_plugin* plugin,
 const void* CLAP_ABI
 clap_plugin_proxy::plugin_get_extension(const struct clap_plugin* plugin,
                                         const char* id) {
-    assert(plugin && plugin->plugin_data);
+    assert(plugin && plugin->plugin_data && id);
     auto self = static_cast<const clap_plugin_proxy*>(plugin->plugin_data);
 
     // TODO: When implementing the GUI option, add a `clap_no_scaling` option to
     //       disable HiDPI scaling just like we have for VST3. Or rename the
     //       existing one.
-
-    // TODO: Implement
-    return nullptr;
+    if (self->supported_extensions_.supports_audio_ports &&
+        strcmp(id, CLAP_EXT_AUDIO_PORTS) == 0) {
+        return &self->ext_audio_ports_vtable;
+    } else {
+        return nullptr;
+    }
 }
 
 void CLAP_ABI
@@ -169,3 +176,25 @@ clap_plugin_proxy::plugin_on_main_thread(const struct clap_plugin* plugin) {
         callback();
     }
 }
+
+uint32_t CLAP_ABI
+clap_plugin_proxy::ext_audio_ports_count(const clap_plugin_t* plugin,
+                                         bool is_input) {
+    assert(plugin && plugin->plugin_data);
+    auto self = static_cast<const clap_plugin_proxy*>(plugin->plugin_data);
+
+    // TODO: Implement
+    return 0;
+}
+
+bool CLAP_ABI
+clap_plugin_proxy::ext_audio_ports_get(const clap_plugin_t* plugin,
+                                       uint32_t index,
+                                       bool is_input,
+                                       clap_audio_port_info_t* info) {
+    assert(plugin && plugin->plugin_data && info);
+    auto self = static_cast<const clap_plugin_proxy*>(plugin->plugin_data);
+
+    // TODO: Implement
+    return false;
+}

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

@@ -19,6 +19,7 @@
 #include <future>
 #include <vector>
 
+#include <clap/ext/audio-ports.h>
 #include <clap/plugin.h>
 #include <rigtorp/MPMCQueue.h>
 #include <function2/function2.hpp>
@@ -93,6 +94,13 @@ class clap_plugin_proxy {
     static void CLAP_ABI
     plugin_on_main_thread(const struct clap_plugin* plugin);
 
+    static uint32_t CLAP_ABI ext_audio_ports_count(const clap_plugin_t* plugin,
+                                                   bool is_input);
+    static bool CLAP_ABI ext_audio_ports_get(const clap_plugin_t* plugin,
+                                             uint32_t index,
+                                             bool is_input,
+                                             clap_audio_port_info_t* info);
+
     /**
      * Asynchronously run a function on the host's main thread, returning the
      * result as a future.
@@ -139,6 +147,11 @@ class clap_plugin_proxy {
      */
     const clap_plugin_t plugin_vtable_;
 
+    // Extensions also have vtables. Whether or not we expose these to the host
+    // depends on whether the plugin supported this extension when we called
+    // `clap_plugin::init()`.
+    const clap_plugin_audio_ports ext_audio_ports_vtable;
+
     /**
      * The extensions supported by the bridged plugin. Set after a successful
      * `clap_plugin::init()` call. We'll allow the host to query these same