From 99b9fbf8eff2fc63e639260bd96e22f058f4f818 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?F=C3=A9lix-Antoine=20Constantin?=
 <60141446+felix642@users.noreply.github.com>
Date: Thu, 30 Nov 2023 13:05:56 -0500
Subject: [PATCH] Add formatter for std::source_location (#3730)

---
 include/fmt/std.h | 30 ++++++++++++++++++++++++++++++
 test/std-test.cc  | 10 ++++++++++
 2 files changed, 40 insertions(+)

diff --git a/include/fmt/std.h b/include/fmt/std.h
index 86c8756f..6f6b23ff 100644
--- a/include/fmt/std.h
+++ b/include/fmt/std.h
@@ -38,6 +38,10 @@
 #  endif
 #endif
 
+#if FMT_CPLUSPLUS > 201703L && FMT_HAS_INCLUDE(<source_location>)
+#  include <source_location>
+#endif
+
 // GCC 4 does not support FMT_HAS_INCLUDE.
 #if FMT_HAS_INCLUDE(<cxxabi.h>) || defined(__GLIBCXX__)
 #  include <cxxabi.h>
@@ -239,6 +243,32 @@ struct formatter<std::optional<T>, Char,
 FMT_END_NAMESPACE
 #endif  // __cpp_lib_optional
 
+#ifdef __cpp_lib_source_location
+FMT_BEGIN_NAMESPACE
+FMT_EXPORT
+template<>
+struct formatter<std::source_location> {
+  template <typename ParseContext> FMT_CONSTEXPR auto parse(ParseContext& ctx) {
+    return ctx.begin();
+  }
+
+  template <typename FormatContext>
+  auto format(const std::source_location& loc, FormatContext& ctx) const
+      -> decltype(ctx.out()) {
+    auto out = ctx.out();
+    out = detail::write(out, loc.file_name());
+    out = detail::write(out, ':');
+    out = detail::write<char>(out, loc.line());
+    out = detail::write(out, ':');
+    out = detail::write<char>(out, loc.column());
+    out = detail::write(out, ": ");
+    out = detail::write(out, loc.function_name());
+    return out;
+  }
+};
+FMT_END_NAMESPACE
+#endif
+
 #if FMT_CPP_LIB_VARIANT
 FMT_BEGIN_NAMESPACE
 namespace detail {
diff --git a/test/std-test.cc b/test/std-test.cc
index 55a48810..2e8ff177 100644
--- a/test/std-test.cc
+++ b/test/std-test.cc
@@ -66,6 +66,16 @@ TEST(std_test, thread_id) {
   EXPECT_FALSE(fmt::format("{}", std::this_thread::get_id()).empty());
 }
 
+#ifdef __cpp_lib_source_location
+TEST(std_test, source_location) {
+  std::source_location loc = std::source_location::current();
+  EXPECT_EQ(fmt::format("{}", loc), std::string(loc.file_name()) + ":" +
+                                        std::to_string(loc.line()) + ":" +
+                                        std::to_string(loc.column()) + ": " +
+                                        loc.function_name());
+}
+#endif
+
 TEST(std_test, optional) {
 #ifdef __cpp_lib_optional
   EXPECT_EQ(fmt::format("{}", std::optional<int>{}), "none");