Prevent allocations in Vst3Logger::log_query_interface

String constants will be converted to `std::string` because it's not
constexpr yet, and that will allocate for longer strings. Since this
function only prints something when `YABRIDGE_DEBUG_LEVEL` is set to 2
or higher that seems like a waste.

CHANGELOG.md

@@ -82,8 +82,8 @@ Versioning](https://semver.org/spec/v2.0.0.html).
 - Fixed the _PG-8X_ VST2 plugin freezing in **REAPER** when loading the plugin.
 - Fixed _Voxengo_ VST2 plugins in **Renoise** freezing when loading a project or
   when otherwise restoring plugin state.
-- Fixed logging traces in the VST2 audio processing functions causing
-  allocations even when `YABRIDGE_DEBUG_LEVEL` is not set to 2.
+- Fixed logging traces in the VST2 audio processing functions and VST3 query
+  interfaces causing allocations even when `YABRIDGE_DEBUG_LEVEL` is not set to 2.
 - Fixed builds on Wine 6.8 because of internal changes to Wine's `windows.h`
   implementation.
 

src/common/logging/vst3.cpp

@@ -54,7 +54,7 @@ std::string format_bstream(const YaBStream& stream) {
 Vst3Logger::Vst3Logger(Logger& generic_logger) : logger(generic_logger) {}
 
 void Vst3Logger::log_query_interface(
-    const std::string& where,
+    const char* where,
     tresult result,
     const std::optional<Steinberg::FUID>& uid) {
     if (logger.verbosity >= Logger::Verbosity::all_events) [[unlikely]] {

src/common/logging/vst3.h

@@ -18,6 +18,8 @@
 
 #include <sstream>
 
+#include <boost/container/string.hpp>
+
 #include "../serialization/vst3.h"
 #include "common.h"
 
@@ -41,8 +43,14 @@ class Vst3Logger {
      * and queries for interfaces we do not implement depending on the verbosity
      * level. In case we could not get a FUID (because of null pointers, for
      * instance), `std::nullopt` should be passed.
+     *
+     * NOTE: We're passing a `const char*` here instead of a `const
+     *       std::string&` because that will still allocate for longer strings
+     *       because `std::string` isn't constexpr yet.  Most calls to this
+     *       function won't print anything, so we should make sure that calling
+     *       it doesn't add unnecessary overhead.
      */
-    void log_query_interface(const std::string& where,
+    void log_query_interface(const char* where,
                              tresult result,
                              const std::optional<Steinberg::FUID>& uid);