Switch to vformat_to

Drive-by: reduce the amount of occurences of #ifdef SPDLOG_USE_STD_FORMAT

include/spdlog/common.h

@@ -44,15 +44,13 @@
 
 #include <spdlog/fmt/fmt.h>
 
-#ifndef SPDLOG_USE_STD_FORMAT
-#    if FMT_VERSION >= 80000 // backward compatibility with fmt versions older than 8
-#        define SPDLOG_FMT_RUNTIME(format_string) fmt::runtime(format_string)
-#        if defined(SPDLOG_WCHAR_FILENAMES) || defined(SPDLOG_WCHAR_TO_UTF8_SUPPORT)
-#            include <spdlog/fmt/xchar.h>
-#        endif
-#    else
-#        define SPDLOG_FMT_RUNTIME(format_string) format_string
+#if !defined(SPDLOG_USE_STD_FORMAT) && FMT_VERSION >= 80000 // backward compatibility with fmt versions older than 8
+#    define SPDLOG_FMT_RUNTIME(format_string) fmt::runtime(format_string)
+#    if defined(SPDLOG_WCHAR_FILENAMES) || defined(SPDLOG_WCHAR_TO_UTF8_SUPPORT)
+#        include <spdlog/fmt/xchar.h>
 #    endif
+#else
+#    define SPDLOG_FMT_RUNTIME(format_string) format_string
 #endif
 
 // visual studio up to 2013 does not support noexcept nor constexpr

include/spdlog/details/fmt_helper.h

@@ -23,6 +23,20 @@ inline spdlog::string_view_t to_string_view(const memory_buf_t &buf) SPDLOG_NOEX
     return spdlog::string_view_t{buf.data(), buf.size()};
 }
 
+#ifdef SPDLOG_USE_STD_FORMAT
+template<typename T>
+std::basic_string<T> to_string(const std::basic_string<T> &buf)
+{
+    return buf;
+}
+#else
+template<typename T, size_t Size>
+std::basic_string<T> to_string(const fmt::basic_memory_buffer<T, Size> &buf)
+{
+    return fmt::to_string(buf);
+}
+#endif
+
 inline void append_string_view(spdlog::string_view_t view, memory_buf_t &dest)
 {
     auto *buf_ptr = view.data();

include/spdlog/details/os-inl.h

@@ -388,11 +388,7 @@ SPDLOG_INLINE std::string filename_to_str(const filename_t &filename)
 {
     memory_buf_t buf;
     wstr_to_utf8buf(filename, buf);
-#    ifdef SPDLOG_USE_STD_FORMAT
-    return buf;
-#    else
-    return fmt::to_string(buf);
-#    endif
+    return fmt_helper::to_string(buf);
 }
 #else
 SPDLOG_INLINE std::string filename_to_str(const filename_t &filename)

include/spdlog/logger.h

@@ -363,13 +363,10 @@ protected:
         }
         SPDLOG_TRY
         {
-#ifdef SPDLOG_USE_STD_FORMAT
-            memory_buf_t buf = std::vformat(fmt, std::make_format_args(std::forward<Args>(args)...));
-#else
             memory_buf_t buf;
-            fmt::detail::vformat_to(buf, fmt, fmt::make_format_args(std::forward<Args>(args)...));
-#endif
-            details::log_msg log_msg(loc, name_, lvl, string_view_t(buf.data(), buf.size()));
+            fmt_lib::vformat_to(std::back_inserter(buf), fmt, fmt_lib::make_format_args(std::forward<Args>(args)...));
+
+            details::log_msg log_msg(loc, name_, lvl, details::fmt_helper::to_string_view(buf));
             log_it_(log_msg, log_enabled, traceback_enabled);
         }
         SPDLOG_LOGGER_CATCH(loc)
@@ -388,13 +385,9 @@ protected:
         SPDLOG_TRY
         {
             // format to wmemory_buffer and convert to utf8
-            ;
-#    ifdef SPDLOG_USE_STD_FORMAT
-            wmemory_buf_t wbuf = std::vformat(fmt, std::make_wformat_args(std::forward<Args>(args)...));
-#    else
             wmemory_buf_t wbuf;
-            fmt::detail::vformat_to(wbuf, fmt, fmt::make_format_args<fmt::wformat_context>(std::forward<Args>(args)...));
-#    endif
+            fmt_lib::vformat_to(std::back_inserter(wbuf), fmt, fmt_lib::make_format_args<fmt_lib::wformat_context>(std::forward<Args>(args)...));
+
             memory_buf_t buf;
             details::os::wstr_to_utf8buf(wstring_view_t(wbuf.data(), wbuf.size()), buf);
             details::log_msg log_msg(loc, name_, lvl, string_view_t(buf.data(), buf.size()));

include/spdlog/sinks/msvc_sink.h

@@ -30,11 +30,8 @@ protected:
     {
         memory_buf_t formatted;
         base_sink<Mutex>::formatter_->format(msg, formatted);
-#    ifdef SPDLOG_USE_STD_FORMAT
-        OutputDebugStringA(formatted.c_str());
-#    else
-        OutputDebugStringA(fmt::to_string(formatted).c_str());
-#    endif
+        formatted.push_back('\0'); // add a null terminator for OutputDebugStringA
+        OutputDebugStringA(formatted.data());
     }
 
     void flush_() override {}

include/spdlog/sinks/ringbuffer_sink.h

@@ -50,11 +50,7 @@ public:
         {
             memory_buf_t formatted;
             base_sink<Mutex>::formatter_->format(q_.at(i), formatted);
-#ifdef SPDLOG_USE_STD_FORMAT
-            ret.push_back(std::move(formatted));
-#else
-            ret.push_back(fmt::to_string(formatted));
-#endif
+            ret.push_back(fmt_helper::to_string(formatted));
         }
         return ret;
     }