Merge pull request gulrak#167 from cpsauer/dynamic-selection-more-app…

…le-platforms
jnhyatt · Jul 30, 2023 · 144954f · 144954f
2 parents 72a76d7 + 48d46cc
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diff --git a/README.md b/README.md
@@ -176,60 +176,83 @@ Everything is in the namespace `ghc::filesystem`, so one way to use it only as
 a fallback could be:
 
 ```cpp
-#ifdef __APPLE__
-#include <Availability.h> // for deployment target to support pre-catalina targets without std::fs 
+#if _MSVC_LANG >= 201703L || __cplusplus >= 201703L && defined(__has_include)
+    // ^ Supports MSVC prior to 15.7 without setting /Zc:__cplusplus to fix __cplusplus
+    // _MSVC_LANG works regardless. But without the switch, the compiler always reported 199711L: https://blogs.msdn.microsoft.com/vcblog/2018/04/09/msvc-now-correctly-reports-__cplusplus/
+    #if __has_include(<filesystem>) // Two stage __has_include needed for MSVC 2015 and per https://gcc.gnu.org/onlinedocs/cpp/_005f_005fhas_005finclude.html
+        #define GHC_USE_STD_FS
+
+        // Old Apple OSs don't support std::filesystem, though the header is available at compile
+        // time. In particular, std::filesystem is unavailable before macOS 10.15, iOS/tvOS 13.0,
+        // and watchOS 6.0.
+        #ifdef __APPLE__
+            #include <Availability.h>
+            // Note: This intentionally uses std::filesystem on any new Apple OS, like visionOS
+            // released after std::filesystem, where std::filesystem is always available.
+            // (All other __<platform>_VERSION_MIN_REQUIREDs will be undefined and thus 0.)
+            #if __MAC_OS_X_VERSION_MIN_REQUIRED && __MAC_OS_X_VERSION_MIN_REQUIRED < 101500 \
+             || __IPHONE_OS_VERSION_MIN_REQUIRED && __IPHONE_OS_VERSION_MIN_REQUIRED < 130000 \
+             || __TV_OS_VERSION_MIN_REQUIRED && __TV_OS_VERSION_MIN_REQUIRED < 130000 \
+             || __WATCH_OS_VERSION_MAX_ALLOWED && __WATCH_OS_VERSION_MAX_ALLOWED < 60000
+                #undef GHC_USE_STD_FS
+            #endif  
+        #endif
+    #endif
 #endif
-#if ((defined(_MSVC_LANG) && _MSVC_LANG >= 201703L) || (defined(__cplusplus) && __cplusplus >= 201703L)) && defined(__has_include)
-#if __has_include(<filesystem>) && (!defined(__MAC_OS_X_VERSION_MIN_REQUIRED) || __MAC_OS_X_VERSION_MIN_REQUIRED >= 101500)
-#define GHC_USE_STD_FS
-#include <filesystem>
-namespace fs = std::filesystem;
-#endif
-#endif
-#ifndef GHC_USE_STD_FS
-#include <ghc/filesystem.hpp>
-namespace fs = ghc::filesystem;
+
+#ifdef GHC_USE_STD_FS
+    #include <filesystem>
+    namespace fs = std::filesystem;
+#else
+    #include "filesystem.hpp"
+    namespace fs = ghc::filesystem;
 #endif
 ```
 
-**Note that this code uses a two-stage preprocessor condition because Visual Studio 2015
-doesn't like the `(<...>)` syntax, even if it could cut evaluation early before. This code also
-used the minimum deployment target to detect if `std::filesystem` really is available on macOS
-compilation.**
-
-**Note also, this detection now works on MSVC versions prior to 15.7 on, or without setting
-the `/Zc:__cplusplus` compile switch that would fix `__cplusplus` on MSVC. (Without the switch
-the compiler always reports `199711L`
-([see](https://blogs.msdn.microsoft.com/vcblog/2018/04/09/msvc-now-correctly-reports-__cplusplus/)),
-but `_MSVC_LANG` works without it.**
-
 If you want to also use the `fstream` wrapper with `path` support as fallback,
 you might use:
 
 ```cpp
-#ifdef __APPLE__
-#include <Availability.h> // for deployment target to support pre-catalina targets without std::fs 
+#if _MSVC_LANG >= 201703L || __cplusplus >= 201703L && defined(__has_include)
+    // ^ Supports MSVC prior to 15.7 without setting /Zc:__cplusplus to fix __cplusplus
+    // _MSVC_LANG works regardless. But without the switch, the compiler always reported 199711L: https://blogs.msdn.microsoft.com/vcblog/2018/04/09/msvc-now-correctly-reports-__cplusplus/
+    #if __has_include(<filesystem>) // Two stage __has_include needed for MSVC 2015 and per https://gcc.gnu.org/onlinedocs/cpp/_005f_005fhas_005finclude.html
+        #define GHC_USE_STD_FS
+
+        // Old Apple OSs don't support std::filesystem, though the header is available at compile
+        // time. In particular, std::filesystem is unavailable before macOS 10.15, iOS/tvOS 13.0,
+        // and watchOS 6.0.
+        #ifdef __APPLE__
+            #include <Availability.h>
+            // Note: This intentionally uses std::filesystem on any new Apple OS, like visionOS
+            // released after std::filesystem, where std::filesystem is always available.
+            // (All other __<platform>_VERSION_MIN_REQUIREDs will be undefined and thus 0.)
+            #if __MAC_OS_X_VERSION_MIN_REQUIRED && __MAC_OS_X_VERSION_MIN_REQUIRED < 101500 \
+             || __IPHONE_OS_VERSION_MIN_REQUIRED && __IPHONE_OS_VERSION_MIN_REQUIRED < 130000 \
+             || __TV_OS_VERSION_MIN_REQUIRED && __TV_OS_VERSION_MIN_REQUIRED < 130000 \
+             || __WATCH_OS_VERSION_MAX_ALLOWED && __WATCH_OS_VERSION_MAX_ALLOWED < 60000
+                #undef GHC_USE_STD_FS
+            #endif  
+        #endif
+    #endif
 #endif
-#if ((defined(_MSVC_LANG) && _MSVC_LANG >= 201703L) || (defined(__cplusplus) && __cplusplus >= 201703L)) && defined(__has_include)
-#if __has_include(<filesystem>) && (!defined(__MAC_OS_X_VERSION_MIN_REQUIRED) || __MAC_OS_X_VERSION_MIN_REQUIRED >= 101500)
-#define GHC_USE_STD_FS
-#include <filesystem>
-namespace fs {
-using namespace std::filesystem;
-using ifstream = std::ifstream;
-using ofstream = std::ofstream;
-using fstream = std::fstream;
-}
-#endif
-#endif
-#ifndef GHC_USE_STD_FS
-#include <ghc/filesystem.hpp>
-namespace fs {
-using namespace ghc::filesystem;
-using ifstream = ghc::filesystem::ifstream;
-using ofstream = ghc::filesystem::ofstream;
-using fstream = ghc::filesystem::fstream;
-}
+
+#ifdef GHC_USE_STD_FS
+    #include <filesystem>
+    namespace fs {
+        using namespace std::filesystem;
+        using ifstream = std::ifstream;
+        using ofstream = std::ofstream;
+        using fstream = std::fstream;
+    }
+#else
+    #include "filesystem.hpp"
+    namespace fs {
+        using namespace ghc::filesystem;
+        using ifstream = ghc::filesystem::ifstream;
+        using ofstream = ghc::filesystem::ofstream;
+        using fstream = ghc::filesystem::fstream;
+    }
 #endif
 ```
 
@@ -269,55 +292,85 @@ If you use the forwarding/implementation approach, you can still use the dynamic
 switching like this:
 
 ```cpp
-#ifdef __APPLE__
-#include <Availability.h> // for deployment target to support pre-catalina targets without std::fs
-#endif
-#if ((defined(_MSVC_LANG) && _MSVC_LANG >= 201703L) || (defined(__cplusplus) && __cplusplus >= 201703L)) && defined(__has_include)
-#if __has_include(<filesystem>) && (!defined(__MAC_OS_X_VERSION_MIN_REQUIRED) || __MAC_OS_X_VERSION_MIN_REQUIRED >= 101500)
-#define GHC_USE_STD_FS
-#include <filesystem>
-namespace fs {
-using namespace std::filesystem;
-using ifstream = std::ifstream;
-using ofstream = std::ofstream;
-using fstream = std::fstream;
-}
+#if _MSVC_LANG >= 201703L || __cplusplus >= 201703L && defined(__has_include)
+    // ^ Supports MSVC prior to 15.7 without setting /Zc:__cplusplus to fix __cplusplus
+    // _MSVC_LANG works regardless. But without the switch, the compiler always reported 199711L: https://blogs.msdn.microsoft.com/vcblog/2018/04/09/msvc-now-correctly-reports-__cplusplus/
+    #if __has_include(<filesystem>) // Two stage __has_include needed for MSVC 2015 and per https://gcc.gnu.org/onlinedocs/cpp/_005f_005fhas_005finclude.html
+        #define GHC_USE_STD_FS
+
+        // Old Apple OSs don't support std::filesystem, though the header is available at compile
+        // time. In particular, std::filesystem is unavailable before macOS 10.15, iOS/tvOS 13.0,
+        // and watchOS 6.0.
+        #ifdef __APPLE__
+            #include <Availability.h>
+            // Note: This intentionally uses std::filesystem on any new Apple OS, like visionOS
+            // released after std::filesystem, where std::filesystem is always available.
+            // (All other __<platform>_VERSION_MIN_REQUIREDs will be undefined and thus 0.)
+            #if __MAC_OS_X_VERSION_MIN_REQUIRED && __MAC_OS_X_VERSION_MIN_REQUIRED < 101500 \
+             || __IPHONE_OS_VERSION_MIN_REQUIRED && __IPHONE_OS_VERSION_MIN_REQUIRED < 130000 \
+             || __TV_OS_VERSION_MIN_REQUIRED && __TV_OS_VERSION_MIN_REQUIRED < 130000 \
+             || __WATCH_OS_VERSION_MAX_ALLOWED && __WATCH_OS_VERSION_MAX_ALLOWED < 60000
+                #undef GHC_USE_STD_FS
+            #endif  
+        #endif
+    #endif
 #endif
-#endif
-#ifndef GHC_USE_STD_FS
-#include <ghc/fs-fwd.hpp>
-namespace fs {
-using namespace ghc::filesystem;
-using ifstream = ghc::filesystem::ifstream;
-using ofstream = ghc::filesystem::ofstream;
-using fstream = ghc::filesystem::fstream;
-}
+
+#ifdef GHC_USE_STD_FS
+    #include <filesystem>
+    namespace fs {
+        using namespace std::filesystem;
+        using ifstream = std::ifstream;
+        using ofstream = std::ofstream;
+        using fstream = std::fstream;
+    }
+#else
+    #include "fs_fwd.hpp"
+    namespace fs {
+        using namespace ghc::filesystem;
+        using ifstream = ghc::filesystem::ifstream;
+        using ofstream = ghc::filesystem::ofstream;
+        using fstream = ghc::filesystem::fstream;
+    }
 #endif
 ```
 
 and in the implementation hiding cpp, you might use (before any include that includes `ghc/fs_fwd.hpp`
 to take precedence:
 
 ```cpp
-#ifdef __APPLE__ // for deployment target to support pre-catalina targets without std::fs 
-#include <Availability.h>
-#endif
-#if ((defined(_MSVC_LANG) && _MSVC_LANG >= 201703L) || (defined(__cplusplus) && __cplusplus >= 201703L)) && defined(__has_include)
-#if __has_include(<filesystem>) && (!defined(__MAC_OS_X_VERSION_MIN_REQUIRED) || __MAC_OS_X_VERSION_MIN_REQUIRED >= 101500)
-#define GHC_USE_STD_FS
-#endif
+#if _MSVC_LANG >= 201703L || __cplusplus >= 201703L && defined(__has_include)
+    // ^ Supports MSVC prior to 15.7 without setting /Zc:__cplusplus to fix __cplusplus
+    // _MSVC_LANG works regardless. But without the switch, the compiler always reported 199711L: https://blogs.msdn.microsoft.com/vcblog/2018/04/09/msvc-now-correctly-reports-__cplusplus/
+    #if __has_include(<filesystem>) // Two stage __has_include needed for MSVC 2015 and per https://gcc.gnu.org/onlinedocs/cpp/_005f_005fhas_005finclude.html
+        #define GHC_USE_STD_FS
+
+        // Old Apple OSs don't support std::filesystem, though the header is available at compile
+        // time. In particular, std::filesystem is unavailable before macOS 10.15, iOS/tvOS 13.0,
+        // and watchOS 6.0.
+        #ifdef __APPLE__
+            #include <Availability.h>
+            // Note: This intentionally uses std::filesystem on any new Apple OS, like visionOS
+            // released after std::filesystem, where std::filesystem is always available.
+            // (All other __<platform>_VERSION_MIN_REQUIREDs will be undefined and thus 0.)
+            #if __MAC_OS_X_VERSION_MIN_REQUIRED && __MAC_OS_X_VERSION_MIN_REQUIRED < 101500 \
+             || __IPHONE_OS_VERSION_MIN_REQUIRED && __IPHONE_OS_VERSION_MIN_REQUIRED < 130000 \
+             || __TV_OS_VERSION_MIN_REQUIRED && __TV_OS_VERSION_MIN_REQUIRED < 130000 \
+             || __WATCH_OS_VERSION_MAX_ALLOWED && __WATCH_OS_VERSION_MAX_ALLOWED < 60000
+                #undef GHC_USE_STD_FS
+            #endif  
+        #endif
+    #endif
 #endif
+
 #ifndef GHC_USE_STD_FS
-#define GHC_FILESYSTEM_IMPLEMENTATION
-#include <ghc/filesystem.hpp>
+    #include "fs_impl.hpp"
 #endif
 ```
 
 :information_source: **Hint:** There are additional helper headers, named `ghc/fs_std_fwd.hpp` and
 `ghc/fs_std_impl.hpp` that use this technique, so you can simply include them
-if you want to dynamically select the filesystem implementation. they also
-enable the `wchar_t` support on `ghc::filesystem` on Windows, so the resulting
-implementation in the `fs` namespace will be compatible.
+if you want to dynamically select the filesystem implementation.
 
 
 
@@ -409,7 +462,7 @@ int main(int argc, char* argv[])
         exit(EXIT_FAILURE);
     }
 
-    // now use argc/argv as usual, they have utf-8 enconding on windows
+    // now use argc/argv as usual, they have utf-8 encoding on windows
     // ...
 
     return 0;

diff --git a/include/ghc/filesystem.hpp b/include/ghc/filesystem.hpp
@@ -25,23 +25,6 @@
 // SOFTWARE.
 //
 //---------------------------------------------------------------------------------------
-//
-// To dynamically select std::filesystem where available on most platforms,
-// you could use:
-//
-// #if ((defined(_MSVC_LANG) && _MSVC_LANG >= 201703L) || (defined(__cplusplus) && __cplusplus >= 201703L)) && defined(__has_include)
-// #if __has_include(<filesystem>) && (!defined(__MAC_OS_X_VERSION_MIN_REQUIRED) || __MAC_OS_X_VERSION_MIN_REQUIRED >= 101500)
-// #define GHC_USE_STD_FS
-// #include <filesystem>
-// namespace fs = std::filesystem;
-// #endif
-// #endif
-// #ifndef GHC_USE_STD_FS
-// #include <ghc/filesystem.hpp>
-// namespace fs = ghc::filesystem;
-// #endif
-//
-//---------------------------------------------------------------------------------------
 #ifndef GHC_FILESYSTEM_H
 #define GHC_FILESYSTEM_H
 
@@ -53,7 +36,7 @@
 
 #ifndef GHC_OS_DETECTED
 #if defined(__APPLE__) && defined(__MACH__)
-#define GHC_OS_MACOS
+#define GHC_OS_APPLE
 #elif defined(__linux__)
 #define GHC_OS_LINUX
 #if defined(__ANDROID__)
@@ -181,7 +164,7 @@
 #include <langinfo.h>
 #endif
 #endif
-#ifdef GHC_OS_MACOS
+#ifdef GHC_OS_APPLE
 #include <Availability.h>
 #endif
 
@@ -4650,9 +4633,11 @@ GHC_INLINE void last_write_time(const path& p, file_time_type new_time, std::err
     if (!::SetFileTime(file.get(), 0, 0, &ft)) {
         ec = detail::make_system_error();
     }
-#elif defined(GHC_OS_MACOS) && \
-    (__MAC_OS_X_VERSION_MIN_REQUIRED < __MAC_10_13) || (__IPHONE_OS_VERSION_MIN_REQUIRED < __IPHONE_11_0) || \
-    (__TV_OS_VERSION_MIN_REQUIRED < __TVOS_11_0) || (__WATCH_OS_VERSION_MIN_REQUIRED < __WATCHOS_4_0)
+#elif defined(GHC_OS_APPLE) && \
+    (__MAC_OS_X_VERSION_MIN_REQUIRED && __MAC_OS_X_VERSION_MIN_REQUIRED < 101300 \
+     || __IPHONE_OS_VERSION_MIN_REQUIRED && __IPHONE_OS_VERSION_MIN_REQUIRED < 110000 \
+     || __TV_OS_VERSION_MIN_REQUIRED && __TVOS_VERSION_MIN_REQUIRED < 110000 \
+     || __WATCH_OS_VERSION_MIN_REQUIRED && __WATCHOS_VERSION_MIN_REQUIRED < 40000)
     struct ::stat fs;
     if (::stat(p.c_str(), &fs) == 0) {
         struct ::timeval tv[2];

diff --git a/include/ghc/fs_fwd.hpp b/include/ghc/fs_fwd.hpp
@@ -25,7 +25,7 @@
 // SOFTWARE.
 //
 //---------------------------------------------------------------------------------------
-// fs_fwd.hpp - The forwarding header for the header/implementation seperated usage of
+// fs_fwd.hpp - The forwarding header for the header/implementation separated usage of
 //              ghc::filesystem.
 // This file can be include at any place, where ghc::filesystem api is needed while
 // not bleeding implementation details (e.g. system includes) into the global namespace,
@@ -34,5 +34,5 @@
 #ifndef GHC_FILESYSTEM_FWD_H
 #define GHC_FILESYSTEM_FWD_H
 #define GHC_FILESYSTEM_FWD
-#include <ghc/filesystem.hpp>
+#include "filesystem.hpp"
 #endif // GHC_FILESYSTEM_FWD_H
diff --git a/include/ghc/fs_impl.hpp b/include/ghc/fs_impl.hpp
@@ -25,11 +25,11 @@
 // SOFTWARE.
 //
 //---------------------------------------------------------------------------------------
-// fs_impl.hpp - The implementation header for the header/implementation seperated usage of
+// fs_impl.hpp - The implementation header for the header/implementation separated usage of
 //               ghc::filesystem.
 // This file can be used to hide the implementation of ghc::filesystem into a single cpp.
 // The cpp has to include this before including fs_fwd.hpp directly or via a different
 // header to work.
 //---------------------------------------------------------------------------------------
 #define GHC_FILESYSTEM_IMPLEMENTATION
-#include <ghc/filesystem.hpp>
+#include "filesystem.hpp"