Add logging for CLAP extension queries

src/common/logging/clap.cpp

@@ -24,6 +24,27 @@
 
 ClapLogger::ClapLogger(Logger& generic_logger) : logger_(generic_logger) {}
 
+void ClapLogger::log_extension_query(const char* where,
+                                     bool result,
+                                     const char* extension_id) {
+    if (logger_.verbosity_ >= Logger::Verbosity::all_events) [[unlikely]] {
+        assert(where && extension_id);
+
+        std::ostringstream message;
+        if (result) {
+            message << "[extension query] " << where << "(extension_id = \""
+                    << extension_id << "\")";
+        } else {
+            // TODO: DIfferentiate between extensions we don't implement and
+            //       extensions the object doesn't implement
+            message << "[unknown extension] " << where << "(extension_id = \""
+                    << extension_id << "\")";
+        }
+
+        log(message.str());
+    }
+}
+
 void ClapLogger::log_callback_request(size_t instance_id) {
     log_request_base(false, Logger::Verbosity::all_events, [&](auto& message) {
         message << instance_id << ": clap_host::request_callback()";

src/common/logging/clap.h

@@ -35,7 +35,22 @@ class ClapLogger {
      */
     inline void log(const std::string& message) { logger_.log(message); }
 
-    // TODO: Logging for extension queries, factory type queries
+    /**
+     * Log calls to `clap_plugin::get_extension()` and
+     * `clap_host::get_extension()`. This makes it possible to tell which
+     * extensions the host or plugin is querying, and which of those we don't
+     * support yet.
+     *
+     * @param where The name of the function where this query occurred. In the
+     *   format `clap_foo::get_extension`, without parentheses. This is a `const
+     *   char*` to avoid allocations.
+     * @param result True if we returned an extension pointer, or false if we
+     *   returned a null pointer.
+     * @param id The ID of the extension the plugin or host was trying to query.
+     */
+    void log_extension_query(const char* where,
+                             bool result,
+                             const char* extension_id);
 
     /**
      * Logging for `clap_host::request_callback()`. This is handled purely on

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

@@ -174,12 +174,16 @@ clap_plugin_proxy::plugin_get_extension(const struct clap_plugin* plugin,
     // 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.
+    const void* extension_ptr = nullptr;
     if (self->supported_extensions_.supports_audio_ports &&
         strcmp(id, CLAP_EXT_AUDIO_PORTS) == 0) {
-        return &self->ext_audio_ports_vtable;
-    } else {
-        return nullptr;
+        extension_ptr = &self->ext_audio_ports_vtable;
     }
+
+    self->bridge_.logger_.log_extension_query("clap_plugin::get_extension",
+                                              extension_ptr, id);
+
+    return extension_ptr;
 }
 
 void CLAP_ABI

src/wine-host/bridges/clap-impls/host-proxy.cpp

@@ -55,12 +55,16 @@ clap_host_proxy::host_get_extension(const struct clap_host* host,
     assert(host && host->host_data && extension_id);
     auto self = static_cast<const clap_host_proxy*>(host->host_data);
 
+    const void* extension_ptr = nullptr;
     if (self->supported_extensions_.supports_audio_ports &&
         strcmp(extension_id, CLAP_EXT_AUDIO_PORTS) == 0) {
-        return &self->ext_audio_ports_vtable;
-    } else {
-        return nullptr;
+        extension_ptr = &self->ext_audio_ports_vtable;
     }
+
+    self->bridge_.logger_.log_extension_query("clap_host::get_extension",
+                                              extension_ptr, extension_id);
+
+    return extension_ptr;
 }
 
 void CLAP_ABI