From 2b067b2c62685f7c4f7afbb7aeb34d55c2cb8733 Mon Sep 17 00:00:00 2001
From: Dan Goodliffe <dan@randomdan.homeip.net>
Date: Fri, 15 Apr 2022 18:28:26 +0100
Subject: If source_location is available, use it for safe numeric conversion
 exception message

---
 netfs/ice/numeric.cpp | 14 ++++++++++++++
 netfs/ice/numeric.h   | 30 ++++++++++++++++++++++++++++--
 2 files changed, 42 insertions(+), 2 deletions(-)

diff --git a/netfs/ice/numeric.cpp b/netfs/ice/numeric.cpp
index 2ec05af..3d86f28 100644
--- a/netfs/ice/numeric.cpp
+++ b/netfs/ice/numeric.cpp
@@ -1,7 +1,21 @@
 #include "numeric.h"
+#include <stdexcept>
+#include <version>
+
+#ifdef __cpp_lib_source_location
+#	include <string>
+
+void
+safe_base::out_of_range(std::string desc)
+{
+	throw std::out_of_range {std::move(desc)};
+}
+
+#else
 
 void
 safe_base::out_of_range(const char * const function)
 {
 	throw std::out_of_range {function};
 }
+#endif
diff --git a/netfs/ice/numeric.h b/netfs/ice/numeric.h
index cdfec2a..302df91 100644
--- a/netfs/ice/numeric.h
+++ b/netfs/ice/numeric.h
@@ -5,17 +5,35 @@
 #include <concepts>
 #include <limits>
 #include <optional>
-#include <stdexcept>
 #include <utility>
+#include <version>
 #include <visibility.h>
 
+#ifdef __cpp_lib_source_location
+#	include <compileTimeFormatter.h>
+#	include <source_location>
+#	include <string>
+AdHocFormatter(ConvPos, "%?:%?(value: %?)");
+#endif
+
 struct DLL_PUBLIC safe_base {
 protected:
+#ifdef __cpp_lib_source_location
+	[[noreturn]] static void out_of_range(std::string);
+#else
 	[[noreturn]] static void out_of_range(const char * const);
+#endif
 };
 
 template<std::integral T> struct safe : safe_base {
+#ifdef __cpp_lib_source_location
+	constexpr explicit safe(T v, const std::source_location w = std::source_location::current()) noexcept :
+		value {v}, where {w}
+	{
+	}
+#else
 	constexpr explicit safe(T v) noexcept : value {v} { }
+#endif
 
 	// NOLINTNEXTLINE(hicpp-explicit-conversions)
 	template<std::integral R> constexpr inline operator R() const
@@ -26,7 +44,12 @@ template<std::integral T> struct safe : safe_base {
 		}
 		else {
 			if (!std::in_range<R>(value)) {
-				[[unlikely]] out_of_range(__PRETTY_FUNCTION__);
+				[[unlikely]]
+#ifdef __cpp_lib_source_location
+				out_of_range(ConvPos::get(where.function_name(), where.line(), value));
+#else
+				out_of_range(__PRETTY_FUNCTION__);
+#endif
 			}
 			return static_cast<R>(value);
 		}
@@ -44,6 +67,9 @@ template<std::integral T> struct safe : safe_base {
 
 private:
 	T value;
+#ifdef __cpp_lib_source_location
+	const std::source_location where;
+#endif
 	constexpr static T min {std::numeric_limits<T>::min()};
 	constexpr static T max {std::numeric_limits<T>::max()};
 };
-- 
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