From f84e720cde699d7c83faee9ec7c74874b8b48366 Mon Sep 17 00:00:00 2001
From: Matthias Moulin <matthias.moulin@gmail.com>
Date: Tue, 9 Apr 2024 20:41:21 +0200
Subject: [PATCH] Added FMT_IMPORT_STD feature macro

---
 include/fmt/args.h       |  8 +++--
 include/fmt/base.h       |  6 ++--
 include/fmt/chrono.h     | 20 ++++++-----
 include/fmt/compile.h    |  4 ++-
 include/fmt/format-inl.h | 14 ++++----
 include/fmt/format.h     | 28 ++++++++-------
 include/fmt/os.h         | 10 +++---
 include/fmt/ostream.h    |  4 ++-
 include/fmt/printf.h     |  6 ++--
 include/fmt/ranges.h     | 10 +++---
 include/fmt/std.h        | 36 ++++++++++---------
 include/fmt/xchar.h      |  6 ++--
 src/fmt.cc               | 76 +++++++++++++++++++++++-----------------
 src/os.cc                |  4 ++-
 14 files changed, 137 insertions(+), 95 deletions(-)

diff --git a/include/fmt/args.h b/include/fmt/args.h
index b77a2d0661122..71c3bb908830f 100644
--- a/include/fmt/args.h
+++ b/include/fmt/args.h
@@ -8,9 +8,11 @@
 #ifndef FMT_ARGS_H_
 #define FMT_ARGS_H_
 
-#include <functional>  // std::reference_wrapper
-#include <memory>      // std::unique_ptr
-#include <vector>
+#ifndef FMT_IMPORT_STD
+#  include <functional>  // std::reference_wrapper
+#  include <memory>      // std::unique_ptr
+#  include <vector>
+#endif
 
 #include "format.h"  // std_string_view
 
diff --git a/include/fmt/base.h b/include/fmt/base.h
index f46d7e470e6d0..64fb15b9981c4 100644
--- a/include/fmt/base.h
+++ b/include/fmt/base.h
@@ -12,9 +12,11 @@
 #include <stdio.h>   // FILE
 #include <string.h>  // strlen
 
+#ifndef FMT_IMPORT_STD
 // <cstddef> is also included transitively from <type_traits>.
-#include <cstddef>      // std::byte
-#include <type_traits>  // std::enable_if
+#  include <cstddef>      // std::byte
+#  include <type_traits>  // std::enable_if
+#endif
 
 // The fmt library version in the form major * 10000 + minor * 100 + patch.
 #define FMT_VERSION 100202
diff --git a/include/fmt/chrono.h b/include/fmt/chrono.h
index d2e10b56b9332..6360d903e9e6a 100644
--- a/include/fmt/chrono.h
+++ b/include/fmt/chrono.h
@@ -8,15 +8,17 @@
 #ifndef FMT_CHRONO_H_
 #define FMT_CHRONO_H_
 
-#include <algorithm>
-#include <chrono>
-#include <cmath>    // std::isfinite
-#include <cstring>  // std::memcpy
-#include <ctime>
-#include <iterator>
-#include <locale>
-#include <ostream>
-#include <type_traits>
+#ifndef FMT_IMPORT_STD
+#  include <algorithm>
+#  include <chrono>
+#  include <cmath>    // std::isfinite
+#  include <cstring>  // std::memcpy
+#  include <ctime>
+#  include <iterator>
+#  include <locale>
+#  include <ostream>
+#  include <type_traits>
+#endif
 
 #include "format.h"
 
diff --git a/include/fmt/compile.h b/include/fmt/compile.h
index d6278521fd0c8..65c68a4b755b2 100644
--- a/include/fmt/compile.h
+++ b/include/fmt/compile.h
@@ -8,7 +8,9 @@
 #ifndef FMT_COMPILE_H_
 #define FMT_COMPILE_H_
 
-#include <iterator>  // std::back_inserter
+#ifndef FMT_IMPORT_STD
+#  include <iterator>  // std::back_inserter
+#endif
 
 #include "format.h"
 
diff --git a/include/fmt/format-inl.h b/include/fmt/format-inl.h
index 5a9afd1ff35a4..5bf56f2cbf553 100644
--- a/include/fmt/format-inl.h
+++ b/include/fmt/format-inl.h
@@ -8,13 +8,15 @@
 #ifndef FMT_FORMAT_INL_H_
 #define FMT_FORMAT_INL_H_
 
-#include <algorithm>
-#include <cerrno>  // errno
-#include <climits>
-#include <cmath>
-#include <exception>
+#ifndef FMT_IMPORT_STD
+#  include <algorithm>
+#  include <cerrno>  // errno
+#  include <climits>
+#  include <cmath>
+#  include <exception>
+#endif
 
-#ifndef FMT_STATIC_THOUSANDS_SEPARATOR
+#if !defined(FMT_STATIC_THOUSANDS_SEPARATOR) && !defined(FMT_IMPORT_STD)
 #  include <locale>
 #endif
 
diff --git a/include/fmt/format.h b/include/fmt/format.h
index 8ab8f263cf721..f15b8dbb5e23d 100644
--- a/include/fmt/format.h
+++ b/include/fmt/format.h
@@ -38,30 +38,34 @@
 #  define FMT_REMOVE_TRANSITIVE_INCLUDES
 #endif
 
-#include <cmath>             // std::signbit
-#include <cstdint>           // uint32_t
-#include <cstring>           // std::memcpy
-#include <initializer_list>  // std::initializer_list
-#include <limits>            // std::numeric_limits
-#if defined(__GLIBCXX__) && !defined(_GLIBCXX_USE_DUAL_ABI)
+#ifndef FMT_IMPORT_STD
+#  include <cmath>             // std::signbit
+#  include <cstdint>           // uint32_t
+#  include <cstring>           // std::memcpy
+#  include <initializer_list>  // std::initializer_list
+#  include <limits>            // std::numeric_limits
+#  if defined(__GLIBCXX__) && !defined(_GLIBCXX_USE_DUAL_ABI)
 // Workaround for pre gcc 5 libstdc++.
-#  include <memory>  // std::allocator_traits
+#    include <memory>  // std::allocator_traits
+#  endif
+#  include <stdexcept>     // std::runtime_error
+#  include <string>        // std::string
+#  include <system_error>  // std::system_error
 #endif
-#include <stdexcept>     // std::runtime_error
-#include <string>        // std::string
-#include <system_error>  // std::system_error
 
 #include "base.h"
 
 // Checking FMT_CPLUSPLUS for warning suppression in MSVC.
-#if FMT_HAS_INCLUDE(<bit>) && FMT_CPLUSPLUS > 201703L
+#if FMT_HAS_INCLUDE(<bit>) && FMT_CPLUSPLUS > 201703L && !defined(FMT_IMPORT_STD)
 #  include <bit>  // std::bit_cast
 #endif
 
 // libc++ supports string_view in pre-c++17.
 #if FMT_HAS_INCLUDE(<string_view>) && \
     (FMT_CPLUSPLUS >= 201703L || defined(_LIBCPP_VERSION))
-#  include <string_view>
+#  ifndef FMT_IMPORT_STD
+#    include <string_view>
+#  endif
 #  define FMT_USE_STRING_VIEW
 #endif
 
diff --git a/include/fmt/os.h b/include/fmt/os.h
index 3a10c9303f11e..c98256920cdcb 100644
--- a/include/fmt/os.h
+++ b/include/fmt/os.h
@@ -8,10 +8,12 @@
 #ifndef FMT_OS_H_
 #define FMT_OS_H_
 
-#include <cerrno>
-#include <cstddef>
-#include <cstdio>
-#include <system_error>  // std::system_error
+#ifndef FMT_IMPORT_STD
+#  include <cerrno>
+#  include <cstddef>
+#  include <cstdio>
+#  include <system_error>  // std::system_error
+#endif
 
 #include "format.h"
 
diff --git a/include/fmt/ostream.h b/include/fmt/ostream.h
index f9ba9d7b25b64..7ab245802611d 100644
--- a/include/fmt/ostream.h
+++ b/include/fmt/ostream.h
@@ -8,7 +8,9 @@
 #ifndef FMT_OSTREAM_H_
 #define FMT_OSTREAM_H_
 
-#include <fstream>  // std::filebuf
+#ifndef FMT_IMPORT_STD
+#  include <fstream>  // std::filebuf
+#endif
 
 #ifdef _WIN32
 #  ifdef __GLIBCXX__
diff --git a/include/fmt/printf.h b/include/fmt/printf.h
index c060952d9e8be..fb57d23585f97 100644
--- a/include/fmt/printf.h
+++ b/include/fmt/printf.h
@@ -8,8 +8,10 @@
 #ifndef FMT_PRINTF_H_
 #define FMT_PRINTF_H_
 
-#include <algorithm>  // std::max
-#include <limits>     // std::numeric_limits
+#ifndef FMT_IMPORT_STD
+#  include <algorithm>  // std::max
+#  include <limits>     // std::numeric_limits
+#endif
 
 #include "format.h"
 
diff --git a/include/fmt/ranges.h b/include/fmt/ranges.h
index f2b0f0e944dce..86f9e01e5ffad 100644
--- a/include/fmt/ranges.h
+++ b/include/fmt/ranges.h
@@ -8,10 +8,12 @@
 #ifndef FMT_RANGES_H_
 #define FMT_RANGES_H_
 
-#include <initializer_list>
-#include <iterator>
-#include <tuple>
-#include <type_traits>
+#ifndef FMT_IMPORT_STD
+#  include <initializer_list>
+#  include <iterator>
+#  include <tuple>
+#  include <type_traits>
+#endif
 
 #include "format.h"
 
diff --git a/include/fmt/std.h b/include/fmt/std.h
index 7085cae8170af..f437a847e636d 100644
--- a/include/fmt/std.h
+++ b/include/fmt/std.h
@@ -8,17 +8,19 @@
 #ifndef FMT_STD_H_
 #define FMT_STD_H_
 
-#include <atomic>
-#include <bitset>
-#include <complex>
-#include <cstdlib>
-#include <exception>
-#include <memory>
-#include <thread>
-#include <type_traits>
-#include <typeinfo>
-#include <utility>
-#include <vector>
+#ifndef FMT_IMPORT_STD
+#  include <atomic>
+#  include <bitset>
+#  include <complex>
+#  include <cstdlib>
+#  include <exception>
+#  include <memory>
+#  include <thread>
+#  include <type_traits>
+#  include <typeinfo>
+#  include <utility>
+#  include <vector>
+#endif
 
 #include "format.h"
 #include "ostream.h"
@@ -28,22 +30,24 @@
 #endif
 // Checking FMT_CPLUSPLUS for warning suppression in MSVC.
 #if FMT_CPLUSPLUS >= 201703L
-#  if FMT_HAS_INCLUDE(<filesystem>)
+#  if FMT_HAS_INCLUDE(<filesystem>) && !defined(FMT_IMPORT_STD)
 #    include <filesystem>
 #  endif
-#  if FMT_HAS_INCLUDE(<variant>)
+#  if FMT_HAS_INCLUDE(<variant>) && !defined(FMT_IMPORT_STD)
 #    include <variant>
 #  endif
-#  if FMT_HAS_INCLUDE(<optional>)
+#  if FMT_HAS_INCLUDE(<optional>) && !defined(FMT_IMPORT_STD)
 #    include <optional>
 #  endif
 #endif
 
-#if FMT_HAS_INCLUDE(<expected>) && FMT_CPLUSPLUS > 202002L
+#if FMT_HAS_INCLUDE(<expected>) && FMT_CPLUSPLUS > 202002L && \
+    !defined(FMT_IMPORT_STD)
 #  include <expected>
 #endif
 
-#if FMT_CPLUSPLUS > 201703L && FMT_HAS_INCLUDE(<source_location>)
+#if FMT_CPLUSPLUS > 201703L && FMT_HAS_INCLUDE(<source_location>) && \
+    !defined(FMT_IMPORT_STD)
 #  include <source_location>
 #endif
 
diff --git a/include/fmt/xchar.h b/include/fmt/xchar.h
index 61a4b54fca5d7..557dbe1d3adbc 100644
--- a/include/fmt/xchar.h
+++ b/include/fmt/xchar.h
@@ -8,13 +8,15 @@
 #ifndef FMT_XCHAR_H_
 #define FMT_XCHAR_H_
 
-#include <cwchar>
+#ifndef FMT_IMPORT_STD
+#  include <cwchar>
+#endif
 
 #include "color.h"
 #include "format.h"
 #include "ranges.h"
 
-#ifndef FMT_STATIC_THOUSANDS_SEPARATOR
+#if !defined(FMT_STATIC_THOUSANDS_SEPARATOR) && !defined(FMT_IMPORT_STD)
 #  include <locale>
 #endif
 
diff --git a/src/fmt.cc b/src/fmt.cc
index 6cff309d41c62..798c026976470 100644
--- a/src/fmt.cc
+++ b/src/fmt.cc
@@ -2,38 +2,46 @@ module;
 
 // Put all implementation-provided headers into the global module fragment
 // to prevent attachment to this module.
-#include <algorithm>
-#include <cerrno>
-#include <chrono>
-#include <climits>
-#include <cmath>
-#include <cstddef>
-#include <cstdint>
-#include <cstdio>
-#include <cstdlib>
-#include <cstring>
-#include <ctime>
-#include <exception>
-#include <filesystem>
-#include <fstream>
-#include <functional>
-#include <iterator>
-#include <limits>
-#include <locale>
-#include <memory>
-#include <optional>
-#include <ostream>
-#include <stdexcept>
-#include <string>
-#include <string_view>
-#include <system_error>
-#include <thread>
-#include <type_traits>
-#include <typeinfo>
-#include <utility>
-#include <variant>
-#include <vector>
-#include <version>
+#ifndef FMT_IMPORT_STD
+#  include <algorithm>
+#  include <cerrno>
+#  include <chrono>
+#  include <climits>
+#  include <cmath>
+#  include <cstddef>
+#  include <cstdint>
+#  include <cstdio>
+#  include <cstdlib>
+#  include <cstring>
+#  include <ctime>
+#  include <exception>
+#  include <filesystem>
+#  include <fstream>
+#  include <functional>
+#  include <iterator>
+#  include <limits>
+#  include <locale>
+#  include <memory>
+#  include <optional>
+#  include <ostream>
+#  include <stdexcept>
+#  include <string>
+#  include <string_view>
+#  include <system_error>
+#  include <thread>
+#  include <type_traits>
+#  include <typeinfo>
+#  include <utility>
+#  include <variant>
+#  include <vector>
+#  include <version>
+#else
+#  include <limits.h>
+#  include <stdint.h>
+#  include <stdio.h>
+#  include <time.h>
+#  include <version>
+#endif
 
 #if __has_include(<cxxabi.h>)
 #  include <cxxabi.h>
@@ -70,6 +78,10 @@ module;
 
 export module fmt;
 
+#ifdef FMT_IMPORT_STD
+import std;
+#endif
+
 #define FMT_EXPORT export
 #define FMT_BEGIN_EXPORT export {
 #define FMT_END_EXPORT }
diff --git a/src/os.cc b/src/os.cc
index 70a4a04c4d3d3..0898c2853714f 100644
--- a/src/os.cc
+++ b/src/os.cc
@@ -12,7 +12,9 @@
 
 #include "fmt/os.h"
 
-#include <climits>
+#ifndef FMT_IMPORT_STD
+#  include <climits>
+#endif
 
 #if FMT_USE_FCNTL
 #  include <sys/stat.h>