no-op LogTrace(); print chars as ints

- LogTrace() (and LogTraceTag, etc.) are now no-ops for release builds.
(hoping there are no side effects in trace logging!)
- renamed llarp::_Log to llarp::_log because _Log is a reserved keyword
- change logging code to implicitly convert 1-byte types (char, unsigned
char, uint8_t) to ints so that we print them as numeric values rather
than raw chars because, more often than not, printing a single char is
trying to log an 8-bit value.

llarp/util/logging/logger.hpp

@@ -82,34 +82,47 @@ namespace llarp
   /** internal */
   template <typename... TArgs>
   inline static void
-  _Log(LogLevel lvl, const char* fname, int lineno, TArgs&&... args) noexcept
+  _log(LogLevel lvl, const char* fname, int lineno, TArgs&&... args) noexcept
   {
     auto& log = LogContext::Instance();
     if (log.curLevel > lvl || log.logStream == nullptr)
       return;
-    std::stringstream ss;
-    LogAppend(ss, std::forward<TArgs>(args)...);
+    std::ostringstream ss;
+    if constexpr (sizeof...(args))
+      LogAppend(ss, std::forward<TArgs>(args)...);
     log.logStream->AppendLog(lvl, fname, lineno, log.nodeName, ss.str());
   }
+
+  inline void _log_noop() noexcept
+  {}
+
 }  // namespace llarp
 
-#define LogTrace(...) _Log(llarp::eLogTrace, LOG_TAG, __LINE__, __VA_ARGS__)
-#define LogDebug(...) _Log(llarp::eLogDebug, LOG_TAG, __LINE__, __VA_ARGS__)
-#define LogInfo(...) _Log(llarp::eLogInfo, LOG_TAG, __LINE__, __VA_ARGS__)
-#define LogWarn(...) _Log(llarp::eLogWarn, LOG_TAG, __LINE__, __VA_ARGS__)
-#define LogError(...) _Log(llarp::eLogError, LOG_TAG, __LINE__, __VA_ARGS__)
-
-#define LogTraceTag(tag, ...) _Log(llarp::eLogTrace, tag, __LINE__, __VA_ARGS__)
-#define LogDebugTag(tag, ...) _Log(llarp::eLogDebug, tag, __LINE__, __VA_ARGS__)
-#define LogInfoTag(tag, ...) _Log(llarp::eLogInfo, tag, __LINE__, __VA_ARGS__)
-#define LogWarnTag(tag, ...) _Log(llarp::eLogWarn, tag, __LINE__, __VA_ARGS__)
-#define LogErrorTag(tag, ...) _Log(llarp::eLogError, tag, __LINE__, __VA_ARGS__)
-
-#define LogTraceExplicit(tag, line, ...) _Log(llarp::eLogTrace, tag, line, __VA_ARGS__)
-#define LogDebugExplicit(tag, line, ...) _Log(llarp::eLogDebug, tag, line, __VA_ARGS__)
-#define LogInfoExplicit(tag, line, ...) _Log(llarp::eLogInfo, tag, line __VA_ARGS__)
-#define LogWarnExplicit(tag, line, ...) _Log(llarp::eLogWarn, tag, line, __VA_ARGS__)
-#define LogErrorExplicit(tag, line, ...) _Log(llarp::eLogError, tag, line, __VA_ARGS__)
+#define LogDebug(...) _log(llarp::eLogDebug, LOG_TAG, __LINE__, __VA_ARGS__)
+#define LogInfo(...) _log(llarp::eLogInfo, LOG_TAG, __LINE__, __VA_ARGS__)
+#define LogWarn(...) _log(llarp::eLogWarn, LOG_TAG, __LINE__, __VA_ARGS__)
+#define LogError(...) _log(llarp::eLogError, LOG_TAG, __LINE__, __VA_ARGS__)
+
+#define LogDebugTag(tag, ...) _log(llarp::eLogDebug, tag, __LINE__, __VA_ARGS__)
+#define LogInfoTag(tag, ...) _log(llarp::eLogInfo, tag, __LINE__, __VA_ARGS__)
+#define LogWarnTag(tag, ...) _log(llarp::eLogWarn, tag, __LINE__, __VA_ARGS__)
+#define LogErrorTag(tag, ...) _log(llarp::eLogError, tag, __LINE__, __VA_ARGS__)
+
+#define LogDebugExplicit(tag, line, ...) _log(llarp::eLogDebug, tag, line, __VA_ARGS__)
+#define LogInfoExplicit(tag, line, ...) _log(llarp::eLogInfo, tag, line __VA_ARGS__)
+#define LogWarnExplicit(tag, line, ...) _log(llarp::eLogWarn, tag, line, __VA_ARGS__)
+#define LogErrorExplicit(tag, line, ...) _log(llarp::eLogError, tag, line, __VA_ARGS__)
+
+// null-op Trace logging if this is a release build
+#ifdef NDEBUG
+#define LogTrace(...) _log_noop()
+#define LogTraceTag(tag, ...) _log_noop()
+#define LogTraceExplicit(tag, line, ...) _log_noop()
+#else
+#define LogTrace(...) _log(llarp::eLogTrace, LOG_TAG, __LINE__, __VA_ARGS__)
+#define LogTraceTag(tag, ...) _log(llarp::eLogTrace, tag, __LINE__, __VA_ARGS__)
+#define LogTraceExplicit(tag, line, ...) _log(llarp::eLogTrace, tag, line, __VA_ARGS__)
+#endif
 
 #ifndef LOG_TAG
 #define LOG_TAG "default"

llarp/util/logging/logger_internal.hpp

@@ -5,20 +5,29 @@
 #include <ctime>
 #include <sstream>
 #include <llarp/util/thread/threading.hpp>
+#include <type_traits>
 
 namespace llarp
 {
-  /** internal, recursion terminator */
-  constexpr void
-  LogAppend(std::stringstream&) noexcept
-  {}
   /** internal */
+
+  // true if T is the same as any of V...
+  template <typename T, typename... V>
+  constexpr bool is_same_any_v = (std::is_same_v<T, V> || ...);
+
   template <typename TArg, typename... TArgs>
   void
-  LogAppend(std::stringstream& ss, TArg&& arg, TArgs&&... args) noexcept
+  LogAppend(std::ostringstream& ss, TArg&& arg, TArgs&&... args) noexcept
   {
-    ss << std::forward<TArg>(arg);
-    LogAppend(ss, std::forward<TArgs>(args)...);
+    // If you are logging a char/unsigned char/uint8_t then promote it to an integer so that we
+    // print numeric values rather than std::ostream's default of printing it as a raw char.
+    using PlainT = std::remove_reference_t<TArg>;
+    if constexpr (is_same_any_v<PlainT, char, unsigned char, signed char, uint8_t, std::byte>)
+        ss << +std::forward<TArg>(arg); // Promote to int
+    else
+        ss << std::forward<TArg>(arg);
+    if constexpr (sizeof...(TArgs))
+        LogAppend(ss, std::forward<TArgs>(args)...);
   }
 
   inline std::string