From 4a056dcd3156795f3716b253a36e9a666ce925c8 Mon Sep 17 00:00:00 2001
From: Robbert van der Helm <mail@robbertvanderhelm.nl>
Date: Wed, 9 Dec 2020 22:11:39 +0100
Subject: [PATCH] Get rid of the VST3 logging boilerplate

---
 src/common/logging/vst3.cpp | 61 +++++++++++--------------------------
 src/common/logging/vst3.h   | 43 +++++++++++++++++++++++---
 2 files changed, 56 insertions(+), 48 deletions(-)

diff --git a/src/common/logging/vst3.cpp b/src/common/logging/vst3.cpp
index f75010be..77e9bdec 100644
--- a/src/common/logging/vst3.cpp
+++ b/src/common/logging/vst3.cpp
@@ -16,79 +16,54 @@
 
 #include "vst3.h"
 
-#include <sstream>
 #include "src/common/serialization/vst3.h"
 
 // TODO: Reconsider the output format
-// TODO: Maybe think of an alterantive that's a little less boilerplaty
 
 Vst3Logger::Vst3Logger(Logger& generic_logger) : logger(generic_logger) {}
 
 void Vst3Logger::log_request(bool is_host_vst, const YaComponent::Create&) {
-    if (BOOST_UNLIKELY(logger.verbosity >= Logger::Verbosity::most_events)) {
-        std::ostringstream message;
+    log_request_base(is_host_vst, [](auto& message) {
         // TODO: Log the cid in some readable way, if possible
-        message << get_log_prefix(is_host_vst)
-                << " >> IPluginFactory::createComponent(cid, IComponent::iid, "
+        message << "IPluginFactory::createComponent(cid, IComponent::iid, "
                    "&obj)";
-
-        log(message.str());
-    }
+    });
 }
 
 void Vst3Logger::log_request(bool is_host_vst, const WantsConfiguration&) {
-    if (BOOST_UNLIKELY(logger.verbosity >= Logger::Verbosity::most_events)) {
-        std::ostringstream message;
-        message << get_log_prefix(is_host_vst)
-                << " >> Requesting <Configuration>";
-
-        log(message.str());
-    }
+    log_request_base(is_host_vst, [](auto& message) {
+        message << "Requesting <Configuration>";
+    });
 }
 
 void Vst3Logger::log_request(bool is_host_vst, const WantsPluginFactory&) {
-    if (BOOST_UNLIKELY(logger.verbosity >= Logger::Verbosity::most_events)) {
-        std::ostringstream message;
-        message << get_log_prefix(is_host_vst)
-                << " >> Requesting <IPluginFactory*>";
-
-        log(message.str());
-    }
+    log_request_base(is_host_vst, [](auto& message) {
+        message << "Requesting <IPluginFactory*>";
+    });
 }
 
 void Vst3Logger::log_response(
     bool is_host_vst,
     const std::optional<YaComponent::Arguments>& args) {
-    if (BOOST_UNLIKELY(logger.verbosity >= Logger::Verbosity::most_events)) {
-        std::ostringstream message;
+    log_response_base(is_host_vst, [&](auto& message) {
         if (args) {
-            message << get_log_prefix(is_host_vst) << "    <IComponent* #"
-                    << args->instance_id << ">";
+            message << "<IComponent* #" << args->instance_id << ">";
         } else {
-            message << get_log_prefix(is_host_vst) << "    <nullptr>";
+            message << "<nullptr>";
         }
-
-        log(message.str());
-    }
+    });
 }
 
 void Vst3Logger::log_response(bool is_host_vst, const Configuration&) {
-    if (BOOST_UNLIKELY(logger.verbosity >= Logger::Verbosity::most_events)) {
-        std::ostringstream message;
-        message << get_log_prefix(is_host_vst) << "    <Configuration>";
-
-        log(message.str());
-    }
+    log_response_base(is_host_vst,
+                      [](auto& message) { message << "<Configuration"; });
 }
 
 void Vst3Logger::log_response(bool is_host_vst,
                               const YaPluginFactory& factory) {
-    if (BOOST_UNLIKELY(logger.verbosity >= Logger::Verbosity::most_events)) {
-        std::ostringstream message;
-        message << get_log_prefix(is_host_vst) << "    <IPluginFactory*> with "
+    log_response_base(is_host_vst, [&](auto& message) {
+        message << "<IPluginFactory*> with "
                 << const_cast<YaPluginFactory&>(factory).countClasses()
                 << " registered classes";
-
-        log(message.str());
-    }
+    });
 }
diff --git a/src/common/logging/vst3.h b/src/common/logging/vst3.h
index 11d75739..529ce3ba 100644
--- a/src/common/logging/vst3.h
+++ b/src/common/logging/vst3.h
@@ -16,6 +16,8 @@
 
 #pragma once
 
+#include <sstream>
+
 #include "../serialization/vst3.h"
 #include "common.h"
 
@@ -58,11 +60,42 @@ class Vst3Logger {
 
    private:
     /**
-     * Get the `host -> vst` or `vst -> host` prefix based on the boolean flag
-     * we pass to every logging function so we don't have to repeat it
-     * everywhere.
+     * Log a request with a standard prefix based on the boolean flag we pass to
+     * every logging function so we don't have to repeat it everywhere.
      */
-    inline std::string get_log_prefix(bool is_host_vst) {
-        return is_host_vst ? "[host -> vst]" : "[vst -> host]";
+    template <std::invocable<std::ostringstream&> F>
+    void log_request_base(bool is_host_vst, F callback) {
+        if (BOOST_UNLIKELY(logger.verbosity >=
+                           Logger::Verbosity::most_events)) {
+            std::ostringstream message;
+            if (is_host_vst) {
+                message << "[host -> vst] >> ";
+            } else {
+                message << "[vst -> host] >> ";
+            }
+
+            callback(message);
+            log(message.str());
+        }
+    }
+
+    /**
+     * Log a response with a standard prefix based on the boolean flag we pass
+     * to every logging function so we don't have to repeat it everywhere.
+     */
+    template <std::invocable<std::ostringstream&> F>
+    void log_response_base(bool is_host_vst, F callback) {
+        if (BOOST_UNLIKELY(logger.verbosity >=
+                           Logger::Verbosity::most_events)) {
+            std::ostringstream message;
+            if (is_host_vst) {
+                message << "[host -> vst]    ";
+            } else {
+                message << "[vst -> host]    ";
+            }
+
+            callback(message);
+            log(message.str());
+        }
     }
 };