Fix <filesystem> linker errors for UWP developers

.clang-format

@@ -186,9 +186,22 @@ SpaceAfterCStyleCast: true
 # SpacesInParentheses: false
 # SpacesInSquareBrackets: false
 # Standard:        Cpp11
+
+# NOTE: _STD_BEGIN, _STD_END, etc. aren't macros for complete statements, but telling clang-format that they are
+# produces the behavior that we want (with no block indentation).
 # StatementMacros:
 #   - Q_UNUSED
 #   - QT_REQUIRE_VERSION
+StatementMacros:
+  - _STD_BEGIN
+  - _STD_END
+  - _STDEXT_BEGIN
+  - _STDEXT_END
+  - _EXTERN_C
+  - _END_EXTERN_C
+  - _EXTERN_C_UNLESS_PURE
+  - _END_EXTERN_C_UNLESS_PURE
+
 # TabWidth:        8
 # UseTab:          Never
 ...

stl/CMakeLists.txt

@@ -237,6 +237,7 @@ endforeach()
 # Objs that exist in both libcpmt[d][01].lib and msvcprt[d].lib.
 set(IMPLIB_SOURCES
     ${CMAKE_CURRENT_LIST_DIR}/src/filesystem.cpp
+    ${CMAKE_CURRENT_LIST_DIR}/src/filesystem_space.cpp
     ${CMAKE_CURRENT_LIST_DIR}/src/locale0_implib.cpp
     ${CMAKE_CURRENT_LIST_DIR}/src/nothrow.cpp
     ${CMAKE_CURRENT_LIST_DIR}/src/parallel_algorithms.cpp

stl/inc/xlocinfo.h

@@ -136,10 +136,9 @@ _Success_(return > 0) _ACRTIMP size_t __cdecl _Wcsftime(
 _END_EXTERN_C
 
 #ifdef _M_CEE_PURE
-    [System::Runtime::InteropServices::DllImport(_CRT_MSVCP_CURRENT, EntryPoint = "_GetLocaleForCP",
-        CallingConvention = System::Runtime::InteropServices::CallingConvention::Cdecl)] extern "C" _locale_t
+[System::Runtime::InteropServices::DllImport(_CRT_MSVCP_CURRENT, EntryPoint = "_GetLocaleForCP",
+    CallingConvention = System::Runtime::InteropServices::CallingConvention::Cdecl)] extern "C" _locale_t
     _GetLocaleForCP(unsigned int);
-
 #else // _M_CEE_PURE
 _MRTIMP2 _locale_t __cdecl _GetLocaleForCP(unsigned int);
 #endif // _M_CEE_PURE

stl/msbuild/stl_base/stl.files.settings.targets

@@ -168,6 +168,7 @@ SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
              (controlled by IncludeInLink and IncludeInImportLib). -->
         <BuildFiles Include="
             $(CrtRoot)\github\stl\src\filesystem.cpp;
+            $(CrtRoot)\github\stl\src\filesystem_space.cpp;
             $(CrtRoot)\github\stl\src\locale0_implib.cpp;
             $(CrtRoot)\github\stl\src\nothrow.cpp;
             $(CrtRoot)\github\stl\src\parallel_algorithms.cpp;

stl/src/filesystem.cpp

@@ -259,28 +259,12 @@ namespace {
 
         return _Last_error;
     }
-
-    static_assert(sizeof(uintmax_t) == sizeof(ULARGE_INTEGER) && alignof(uintmax_t) == alignof(ULARGE_INTEGER),
-        "Size and alignment must match for reinterpret_cast<PULARGE_INTEGER>");
-
-    [[nodiscard]] __std_win_error _Fs_space_attempt(wchar_t* const _Temp_buffer, const DWORD _Temp_buffer_characters,
-        const wchar_t* const _Target, uintmax_t* const _Available, uintmax_t* const _Total_bytes,
-        uintmax_t* const _Free_bytes) noexcept {
-        if (GetVolumePathNameW(_Target, _Temp_buffer, _Temp_buffer_characters)) {
-            if (GetDiskFreeSpaceExW(_Temp_buffer, reinterpret_cast<PULARGE_INTEGER>(_Available),
-                    reinterpret_cast<PULARGE_INTEGER>(_Total_bytes), reinterpret_cast<PULARGE_INTEGER>(_Free_bytes))) {
-                return __std_win_error::_Success;
-            }
-        }
-
-        return __std_win_error{GetLastError()};
-    }
 } // unnamed namespace
 
 _EXTERN_C
 
-    [[nodiscard]] __std_ulong_and_error __stdcall __std_fs_get_full_path_name(
-        const wchar_t* _Source, unsigned long _Target_size, wchar_t* _Target) noexcept { // calls GetFullPathNameW
+[[nodiscard]] __std_ulong_and_error __stdcall __std_fs_get_full_path_name(
+    const wchar_t* _Source, unsigned long _Target_size, wchar_t* _Target) noexcept { // calls GetFullPathNameW
     const auto _Result = GetFullPathNameW(_Source, _Target_size, _Target, nullptr);
     return {_Result, _Result == 0 ? __std_win_error{GetLastError()} : __std_win_error::_Success};
 }
@@ -760,43 +744,6 @@ __std_win_error __stdcall __std_fs_get_file_id(__std_fs_file_id* const _Id, cons
     return __std_win_error::_Success;
 }
 
-[[nodiscard]] __std_win_error __stdcall __std_fs_space(const wchar_t* const _Target, uintmax_t* const _Available,
-    uintmax_t* const _Total_bytes, uintmax_t* const _Free_bytes) noexcept {
-    // get capacity information for the volume on which the file _Target resides
-    __std_win_error _Last_error;
-    if (GetFileAttributesW(_Target) == INVALID_FILE_ATTRIBUTES) {
-        _Last_error = __std_win_error{GetLastError()};
-    } else {
-        {
-            constexpr DWORD _Static_size = MAX_PATH;
-            wchar_t _Temp_buf[_Static_size];
-            _Last_error = _Fs_space_attempt(_Temp_buf, _Static_size, _Target, _Available, _Total_bytes, _Free_bytes);
-            if (_Last_error == __std_win_error::_Success) {
-                return __std_win_error::_Success;
-            }
-        }
-
-        if (_Last_error == __std_win_error::_Filename_exceeds_range) {
-            constexpr DWORD _Dynamic_size = USHRT_MAX + 1; // assuming maximum NT path fits in a UNICODE_STRING
-            const auto _Temp_buf          = _malloc_crt_t(wchar_t, _Dynamic_size);
-            if (_Temp_buf) {
-                _Last_error =
-                    _Fs_space_attempt(_Temp_buf.get(), _Dynamic_size, _Target, _Available, _Total_bytes, _Free_bytes);
-                if (_Last_error == __std_win_error::_Success) {
-                    return __std_win_error::_Success;
-                }
-            } else {
-                _Last_error = __std_win_error::_Not_enough_memory;
-            }
-        }
-    }
-
-    *_Available   = ~0ull;
-    *_Total_bytes = ~0ull;
-    *_Free_bytes  = ~0ull;
-    return _Last_error;
-}
-
 [[nodiscard]] __std_ulong_and_error __stdcall __std_fs_get_temp_path(wchar_t* const _Target) noexcept {
     // calls GetTempPathW
     // If getting the path failed, returns 0 size; otherwise, returns the size of the

stl/src/filesystem_space.cpp

@@ -0,0 +1,73 @@
+// Copyright (c) Microsoft Corporation.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+
+// This must be as small as possible, because its contents are
+// injected into the msvcprt.lib and msvcprtd.lib import libraries.
+// Do not include or define anything else here.
+// In particular, basic_string must not be included here.
+
+// TRANSITION, the code in this file should be moved back to filesystem.cpp
+// when a Windows 10 SDK beyond version 1903 is available (see GH-322).
+
+#include <internal_shared.h>
+#include <limits.h>
+#include <xfilesystem_abi.h>
+
+#include <Windows.h>
+
+namespace {
+    static_assert(sizeof(uintmax_t) == sizeof(ULARGE_INTEGER) && alignof(uintmax_t) == alignof(ULARGE_INTEGER),
+        "Size and alignment must match for reinterpret_cast<PULARGE_INTEGER>");
+
+    [[nodiscard]] __std_win_error _Fs_space_attempt(wchar_t* const _Temp_buffer, const DWORD _Temp_buffer_characters,
+        const wchar_t* const _Target, uintmax_t* const _Available, uintmax_t* const _Total_bytes,
+        uintmax_t* const _Free_bytes) noexcept {
+        if (GetVolumePathNameW(_Target, _Temp_buffer, _Temp_buffer_characters)) {
+            if (GetDiskFreeSpaceExW(_Temp_buffer, reinterpret_cast<PULARGE_INTEGER>(_Available),
+                    reinterpret_cast<PULARGE_INTEGER>(_Total_bytes), reinterpret_cast<PULARGE_INTEGER>(_Free_bytes))) {
+                return __std_win_error::_Success;
+            }
+        }
+
+        return __std_win_error{GetLastError()};
+    }
+} // unnamed namespace
+
+_EXTERN_C
+[[nodiscard]] __std_win_error __stdcall __std_fs_space(const wchar_t* const _Target, uintmax_t* const _Available,
+    uintmax_t* const _Total_bytes, uintmax_t* const _Free_bytes) noexcept {
+    // get capacity information for the volume on which the file _Target resides
+    __std_win_error _Last_error;
+    if (GetFileAttributesW(_Target) == INVALID_FILE_ATTRIBUTES) {
+        _Last_error = __std_win_error{GetLastError()};
+    } else {
+        {
+            constexpr DWORD _Static_size = MAX_PATH;
+            wchar_t _Temp_buf[_Static_size];
+            _Last_error = _Fs_space_attempt(_Temp_buf, _Static_size, _Target, _Available, _Total_bytes, _Free_bytes);
+            if (_Last_error == __std_win_error::_Success) {
+                return __std_win_error::_Success;
+            }
+        }
+
+        if (_Last_error == __std_win_error::_Filename_exceeds_range) {
+            constexpr DWORD _Dynamic_size = USHRT_MAX + 1; // assuming maximum NT path fits in a UNICODE_STRING
+            const auto _Temp_buf          = _malloc_crt_t(wchar_t, _Dynamic_size);
+            if (_Temp_buf) {
+                _Last_error =
+                    _Fs_space_attempt(_Temp_buf.get(), _Dynamic_size, _Target, _Available, _Total_bytes, _Free_bytes);
+                if (_Last_error == __std_win_error::_Success) {
+                    return __std_win_error::_Success;
+                }
+            } else {
+                _Last_error = __std_win_error::_Not_enough_memory;
+            }
+        }
+    }
+
+    *_Available   = ~0ull;
+    *_Total_bytes = ~0ull;
+    *_Free_bytes  = ~0ull;
+    return _Last_error;
+}
+_END_EXTERN_C

stl/src/future.cpp

@@ -4,15 +4,14 @@
 #include <cstdlib>
 #include <exception>
 #include <future>
+
 _STD_BEGIN
 
-    [[noreturn]] _CRTIMP2_PURE void __CLRCALL_PURE_OR_CDECL
-    _Throw_future_error(const error_code& _Code) { // throw an exception
+[[noreturn]] _CRTIMP2_PURE void __CLRCALL_PURE_OR_CDECL _Throw_future_error(const error_code& _Code) {
     _THROW(future_error(_Code));
 }
 
-[[noreturn]] _CRTIMP2_PURE void __CLRCALL_PURE_OR_CDECL _Rethrow_future_exception(
-    exception_ptr _Ptr) { // rethrow an exception
+[[noreturn]] _CRTIMP2_PURE void __CLRCALL_PURE_OR_CDECL _Rethrow_future_exception(exception_ptr _Ptr) {
     _STD rethrow_exception(_Ptr);
 }
 

stl/src/locale0.cpp

@@ -18,9 +18,7 @@
 #pragma init_seg(lib)
 
 _STD_BEGIN
-
-    [[noreturn]] _CRTIMP2_PURE void __CLRCALL_PURE_OR_CDECL
-    _Xbad_alloc();
+[[noreturn]] _CRTIMP2_PURE void __CLRCALL_PURE_OR_CDECL _Xbad_alloc();
 
 struct _Fac_node { // node for lazy facet recording
     _Fac_node(_Fac_node* _Nextarg, _Facet_base* _Facptrarg)

stl/src/xthrow.cpp

@@ -9,9 +9,7 @@
 #include <stdexcept>
 
 _STD_BEGIN
-
-    [[noreturn]] _CRTIMP2_PURE void __CLRCALL_PURE_OR_CDECL
-    _Xbad_alloc() {
+[[noreturn]] _CRTIMP2_PURE void __CLRCALL_PURE_OR_CDECL _Xbad_alloc() {
     _THROW(bad_alloc{});
 }