use std::filesystem instead of std::experimental::filesystem

include/nana/filesystem/filesystem.hpp

@@ -538,13 +538,20 @@ namespace std {
 	namespace filesystem {
 		using namespace std::experimental::filesystem;
 
-#if (defined(_MSC_VER) && ((!defined(_MSVC_LANG)) || (_MSVC_LANG < 201703)))
+#if defined(NANA_FILESYSTEM_FORCE) || \
+    (defined(_MSC_VER) && ((!defined(_MSVC_LANG)) || (_MSVC_LANG < 201703)))
 		path absolute(const path& p);
 		path absolute(const path& p, std::error_code& err);
 
 		path canonical(const path& p);
 		path canonical(const path& p, std::error_code& err);
 #endif
+
+#if defined(NANA_FILESYSTEM_FORCE) || defined(NANA_MINGW)
+        bool exists( std::filesystem::file_status s ) noexcept;
+        bool exists( const std::filesystem::path& p );
+        bool exists( const std::filesystem::path& p, std::error_code& ec ) noexcept;
+#endif
 	}
 } // std
 

include/nana/paint/detail/image_impl_interface.hpp

@@ -16,7 +16,7 @@ namespace nana{	namespace paint{
 	public:
 		using graph_reference = nana::paint::graphics&;
 		virtual ~image_impl_interface() = 0;	//The destructor is defined in ../image.cpp
-		virtual bool open(const std::experimental::filesystem::path& file) = 0;
+		virtual bool open(const std::filesystem::path& file) = 0;
 		virtual bool open(const void* data, std::size_t bytes) = 0; // reads image from memory
 		virtual bool alpha_channel() const = 0;
 		virtual bool empty() const = 0;

include/nana/paint/graphics.hpp

@@ -33,7 +33,7 @@ namespace nana
 		{
 			friend class graphics;
 		public:
-			using path_type = ::std::experimental::filesystem::path;
+			using path_type = ::std::filesystem::path;
 
 			using font_style = ::nana::detail::font_style;
 

source/detail/platform_abstraction.cpp

@@ -158,7 +158,7 @@ namespace nana
 		: public font_interface
 	{
 	public:
-		using path_type = std::experimental::filesystem::path;
+		using path_type = std::filesystem::path;
 
 		internal_font(const path_type& ttf, const std::string& font_family, double font_size, const font_style& fs, native_font_type native_font):
 			ttf_(ttf),

source/detail/platform_abstraction.hpp

@@ -28,7 +28,7 @@ namespace nana
 	public:
 		using font = font_interface;
 
-		using path_type = ::std::experimental::filesystem::path;
+		using path_type = ::std::filesystem::path;
 
 		static void initialize();
 		/// Shutdown before destruction of platform_spec 

source/detail/posix/theme.cpp

@@ -1,3 +1,5 @@
+#include <nana/c++defines.hpp>
+#if defined(NANA_POSIX) && defined(NANA_X11)
 #include "theme.hpp"
 #include <nana/filesystem/filesystem.hpp>
 #include <algorithm>
@@ -296,3 +298,4 @@ namespace nana
 	}
 
 }
+#endif

source/filesystem/filesystem.cpp

@@ -1123,11 +1123,12 @@ namespace nana {	namespace experimental {	namespace filesystem
 	} //end namespace experimental
 }//end namespace nana
 
-#if (defined(_MSC_VER) && ((!defined(_MSVC_LANG)) || (_MSVC_LANG < 201703)))
 namespace std
 {
 	namespace filesystem
 	{
+#if defined(NANA_FILESYSTEM_FORCE) || \
+    (defined(_MSC_VER) && ((!defined(_MSVC_LANG)) || (_MSVC_LANG < 201703)))
 		path absolute(const path& p)
 		{
 			if (p.empty())
@@ -1236,9 +1237,26 @@ namespace std
 		{
 			return canonical(p, &err);
 		}
+#endif
+
+#if defined(NANA_FILESYSTEM_FORCE) || defined(NANA_MINGW)
+    bool exists( std::filesystem::file_status s ) noexcept
+    {
+        return s.type() != file_type::not_found;
+    }
+
+    bool exists( const std::filesystem::path& p )
+    {
+        return exists(status(p));
+    }
+
+    bool exists( const std::filesystem::path& p, std::error_code& ec ) noexcept
+    {
+        return exists(status(p, ec));
+    }
+#endif
 	}//end namespace filesystem
 }//end namespace std
-#endif
 
 #endif
 

source/gui/dragdrop.cpp

@@ -19,6 +19,7 @@
 
 #include <map>
 #include <set>
+#include <cstring>
 
 #ifdef NANA_WINDOWS
 #	include <windows.h>

source/paint/detail/image_bmp.hpp

@@ -111,11 +111,11 @@ namespace nana{	namespace paint
 				return true;
 			}
 
-			bool open(const std::experimental::filesystem::path& filename) override
+			bool open(const std::filesystem::path& filename) override
 			{
 				std::ifstream ifs(filename.string(), std::ios::binary);
 
-				auto const bytes = static_cast<unsigned>(std::experimental::filesystem::file_size(filename));
+				auto const bytes = static_cast<unsigned>(std::filesystem::file_size(filename));
 				if (ifs && (bytes > static_cast<int>(sizeof(bitmap_file_header))))
 				{
 					std::unique_ptr<char[]> buffer{ new char[bytes] };

source/paint/detail/image_ico.hpp

@@ -241,7 +241,7 @@ public:
 #endif
 	}
 
-	bool open(const std::experimental::filesystem::path& ico_file) override
+	bool open(const std::filesystem::path& ico_file) override
 	{
 		std::ifstream file(ico_file.string(), std::ios::binary);
 		if (!file.is_open()) return false;
@@ -290,7 +290,7 @@ public:
 #endif
 	}
 private:
-	std::experimental::filesystem::path path_;
+	std::filesystem::path path_;
 #if defined(NANA_WINDOWS)
 	void* native_handle_{nullptr};
 #endif

source/paint/detail/image_ico_resource.hpp

@@ -29,7 +29,7 @@ namespace nana{	namespace paint
 			:public image::image_impl_interface
 		{
 		public:
-			bool open(const std::experimental::filesystem::path& filename) override
+			bool open(const std::filesystem::path& filename) override
 			{
 #if defined(NANA_WINDOWS)
 				SHFILEINFO sfi;

source/paint/detail/image_jpeg.hpp

@@ -47,7 +47,7 @@ namespace nana
 				}
 			}
 		public:
-			bool open(const std::experimental::filesystem::path& jpeg_file) override
+			bool open(const std::filesystem::path& jpeg_file) override
 			{
 				auto fp = ::fopen(to_osmbstr(to_utf8(jpeg_file.native())).c_str(), "rb");
 				if(nullptr == fp) return false;

source/paint/detail/image_png.hpp

@@ -123,7 +123,7 @@ namespace nana
 				delete[] row_ptrs;
 			}
 		public:
-			bool open(const std::experimental::filesystem::path& png_file) override
+			bool open(const std::filesystem::path& png_file) override
 			{
 				auto fp = ::fopen(to_osmbstr(to_utf8(png_file.native())).c_str(), "rb");
 				if(nullptr == fp) return false;

source/paint/image.cpp

@@ -38,7 +38,7 @@
 #include "detail/image_ico_resource.hpp"
 #include "detail/image_ico.hpp"
 
-namespace fs = std::experimental::filesystem;
+namespace fs = std::filesystem;
 
 namespace nana
 {

source/paint/truetype.hpp

@@ -47,7 +47,7 @@ namespace nana
 				std::uint16_t string_offset; //from start of storage area
 			};
 		public:
-			using path_type = ::std::experimental::filesystem::path;
+			using path_type = ::std::filesystem::path;
 
 			truetype(const path_type& filename)
 			{