From dd48093c230db60f7d96e7353ca061463e381891 Mon Sep 17 00:00:00 2001
From: Kawe Mazidjatari <48657826+Mauler125@users.noreply.github.com>
Date: Mon, 20 Mar 2023 00:17:29 +0100
Subject: [PATCH] Add experimental switch header

This header allows us to properly switch between experimental/finished STD implementations without having to adjust the source code (required for compiling on older versions of the Visual Studio 2017 compiler).
---
 r5dev/common/experimental.h   | 65 +++++++++++++++++++++++++++++++++++
 r5dev/common/sdkdefs.h        |  2 --
 r5dev/core/stdafx.h           |  1 +
 r5dev/naveditor/Editor.cpp    |  8 ++---
 r5dev/thirdparty/recast/Pch.h |  3 +-
 5 files changed, 72 insertions(+), 7 deletions(-)
 create mode 100644 r5dev/common/experimental.h

diff --git a/r5dev/common/experimental.h b/r5dev/common/experimental.h
new file mode 100644
index 00000000..2d99ef01
--- /dev/null
+++ b/r5dev/common/experimental.h
@@ -0,0 +1,65 @@
+//===========================================================================//
+//
+// Purpose: Switch between experimental/finished 'standard' headers.
+//
+// $NoKeywords: $
+//===========================================================================//
+#ifndef EXPERIMENTAL_H
+#define EXPERIMENTAL_H
+
+///////////////////////////////////////////////////////////////////////////////
+// FILESYSTEM
+///////////////////////////////////////////////////////////////////////////////
+#ifndef INCLUDE_STD_FILESYSTEM_EXPERIMENTAL
+#   if defined(__cpp_lib_filesystem) // Check for feature test macro for <filesystem>.
+#       define INCLUDE_STD_FILESYSTEM_EXPERIMENTAL 0
+
+// Check for feature test macro for <experimental/filesystem>.
+#   elif defined(__cpp_lib_experimental_filesystem)
+#       define INCLUDE_STD_FILESYSTEM_EXPERIMENTAL 1
+
+#   elif !defined(__has_include) // We can't check if headers exist (assuming experimental to be safe).
+#       define INCLUDE_STD_FILESYSTEM_EXPERIMENTAL 1
+
+#   elif __has_include(<filesystem>) // Check if the header "<filesystem>" exists.
+
+// If we're compiling on Visual Studio and are not compiling with C++17, we need to use experimental.
+#       ifdef _MSC_VER
+
+// Check and include header that defines "_HAS_CXX17".
+#           if __has_include(<yvals_core.h>)
+#               include <yvals_core.h>
+
+#               if defined(_HAS_CXX17) && _HAS_CXX17
+#                   define INCLUDE_STD_FILESYSTEM_EXPERIMENTAL 0
+#               endif
+#           endif
+
+// If the marco isn't defined yet, that means any of the other VS specific checks failed, so we need to use experimental.
+#           ifndef INCLUDE_STD_FILESYSTEM_EXPERIMENTAL
+#               define INCLUDE_STD_FILESYSTEM_EXPERIMENTAL 1
+#           endif
+
+#       else // #ifdef _MSC_VER
+#           define INCLUDE_STD_FILESYSTEM_EXPERIMENTAL 0
+#       endif
+
+#   elif __has_include(<experimental/filesystem>)
+#       define INCLUDE_STD_FILESYSTEM_EXPERIMENTAL 1
+
+#   else
+#       error Could not find system header "<filesystem>" or "<experimental/filesystem>"
+#   endif
+
+#   if INCLUDE_STD_FILESYSTEM_EXPERIMENTAL
+#       include <experimental/filesystem>
+namespace fs = std::experimental::filesystem;
+
+#   else // We have a recent compiler and can use the finished version.
+// Include it
+#       include <filesystem>
+namespace fs = std::filesystem;
+#   endif
+#endif// !INCLUDE_STD_FILESYSTEM_EXPERIMENTAL
+
+#endif // EXPERIMENTAL_H
\ No newline at end of file
diff --git a/r5dev/common/sdkdefs.h b/r5dev/common/sdkdefs.h
index a06e49b4..5dc3473d 100644
--- a/r5dev/common/sdkdefs.h
+++ b/r5dev/common/sdkdefs.h
@@ -16,8 +16,6 @@ using std::stringstream;
 using std::ostringstream;
 using std::unordered_map;
 
-namespace fs = std::filesystem;
-
 typedef DWORD ThreadId_t;
 typedef uintptr_t uintp;
 typedef intptr_t intp;
diff --git a/r5dev/core/stdafx.h b/r5dev/core/stdafx.h
index 0bc5e8dd..45e98305 100644
--- a/r5dev/core/stdafx.h
+++ b/r5dev/core/stdafx.h
@@ -95,6 +95,7 @@
 
 #include "thirdparty/curl/include/curl/curl.h"
 
+#include "common/experimental.h"
 #include "common/pseudodefs.h"
 #include "common/x86defs.h"
 #include "common/sdkdefs.h"
diff --git a/r5dev/naveditor/Editor.cpp b/r5dev/naveditor/Editor.cpp
index 549a5f1d..4854e306 100644
--- a/r5dev/naveditor/Editor.cpp
+++ b/r5dev/naveditor/Editor.cpp
@@ -317,8 +317,8 @@ void Editor::renderOverlayToolStates(double* proj, double* model, int* view)
 
 dtNavMesh* Editor::loadAll(std::string path)
 {
-	std::filesystem::path p = "..\\maps\\navmesh\\";
-	if (std::filesystem::is_directory(p))
+	fs::path p = "..\\maps\\navmesh\\";
+	if (fs::is_directory(p))
 	{
 		path.insert(0, p.string());
 	}
@@ -406,8 +406,8 @@ void Editor::saveAll(std::string path, dtNavMesh* mesh)
 	if (!mesh)
 		return;
 
-	std::filesystem::path p = "..\\maps\\navmesh\\";
-	if (std::filesystem::is_directory(p))
+	fs::path p = "..\\maps\\navmesh\\";
+	if (fs::is_directory(p))
 	{
 		path.insert(0, p.string());
 	}
diff --git a/r5dev/thirdparty/recast/Pch.h b/r5dev/thirdparty/recast/Pch.h
index cab23685..eb861ae9 100644
--- a/r5dev/thirdparty/recast/Pch.h
+++ b/r5dev/thirdparty/recast/Pch.h
@@ -19,7 +19,8 @@
 #include <set>
 #include <vector>
 #include <algorithm>
-#include <filesystem>
+
+#include "common/experimental.h"
 
 #include "thirdparty/fastlz/fastlz.h"