Replace all use of POSIX truncate

Use `<filesystem>` instead of `truncate` and remove `truncate`
portability wrapper.

Add a helper function `StatusFromSystemError` to convert error_code to
`Status`.

Signed-off-by: Ralph Sennhauser <ralph.sennhauser@gmail.com>

source/lib/file/io/io.h

@@ -1,4 +1,4 @@
-/* Copyright (C) 2025 Wildfire Games.
+/* Copyright (C) 2026 Wildfire Games.
  *
  * Permission is hereby granted, free of charge, to any person obtaining
  * a copy of this software and associated documentation files (the
@@ -38,7 +38,7 @@
 #include "lib/posix/posix_aio.h"	// LIO_READ, LIO_WRITE
 #include "lib/posix/posix_types.h"
 #include "lib/status.h"
-#include "lib/sysdep/filesystem.h"	// wtruncate
+#include "lib/sysdep/filesystem.h"
 #include "lib/sysdep/os.h"
 #include "lib/sysdep/rtl.h"
 #include "lib/types.h"
@@ -47,7 +47,9 @@
 #include <cstddef>
 #include <cstdint>
 #include <fcntl.h>
+#include <filesystem>
 #include <memory>
+#include <system_error>
 
 namespace ERR
 {
@@ -332,9 +334,12 @@ static inline Status Store(const OsPath& pathname, const void* data, size_t size
 
 	RETURN_STATUS_IF_ERR(io::Run(op, p, completedHook, issueHook));
 
-	file.Close();	// (required by wtruncate)
+	file.Close();	// (required by resize_file)
 
-	RETURN_STATUS_IF_ERR(wtruncate(pathname, size));
+	std::error_code ec{};
+	std::filesystem::resize_file(pathname.string(), size, ec);
+	if (ec)
+		return StatusFromSystemError(ec);
 
 	return INFO::OK;
 }

source/lib/status.cpp

@@ -1,4 +1,4 @@
-/* Copyright (C) 2025 Wildfire Games.
+/* Copyright (C) 2026 Wildfire Games.
  *
  * Permission is hereby granted, free of charge, to any person obtaining
  * a copy of this software and associated documentation files (the
@@ -100,6 +100,16 @@ int ErrnoFromStatus(Status status)
 	return EPERM;
 }
 
+Status StatusFromSystemError(std::error_code& ec)
+{
+	if (!ec)
+		return INFO::OK;
+	std::error_condition cond = ec.default_error_condition();
+	if (cond.category() != std::generic_category())
+		return ERR::FAIL;
+	const StatusDefinition* def = DefinitionFromErrno(cond.value());
+	return def ? def->status : ERR::FAIL;
+}
 
 Status StatusFromErrno()
 {

source/lib/status.h

@@ -1,4 +1,4 @@
-/* Copyright (C) 2025 Wildfire Games.
+/* Copyright (C) 2026 Wildfire Games.
  *
  * Permission is hereby granted, free of charge, to any person obtaining
  * a copy of this software and associated documentation files (the
@@ -165,6 +165,7 @@ To summarize: +/-1SHHCC (S=subsystem, HH=header, CC=code number)
 #include "lib/types.h"
 
 #include <cstddef>
+#include <system_error>
 
 // an integral type allows defining error codes in separate headers,
 // but is not as type-safe as an enum. use Lint's 'strong type' checking
@@ -246,6 +247,11 @@ extern int ErrnoFromStatus(Status status);
  **/
 extern Status StatusFromErrno();
 
+/**
+ * @return Status equivalent of error_code, or ERR::FAIL if there's no equivalent.
+ */
+extern Status StatusFromSystemError(std::error_code& ec);
+
 // note: other conversion routines (e.g. to/from Win32) are implemented in
 // the corresponding modules to keep this header portable.
 

source/lib/sysdep/filesystem.h

@@ -56,18 +56,6 @@ extern int wopen(const OsPath& pathname, int oflag, mode_t mode);
 extern int wclose(int fd);
 
 
-//
-// unistd.h
-//
-
-// waio requires offsets and sizes to be multiples of the sector size.
-// to allow arbitrarily sized files, we truncate them after I/O.
-// however, ftruncate cannot be used since it is also subject to the
-// sector-alignment requirement. instead, the file must be closed and
-// this function called.
-int wtruncate(const OsPath& pathname, off_t length);
-
-
 //
 // stdlib.h
 //

source/lib/sysdep/os/unix/ufilesystem.cpp

@@ -93,11 +93,6 @@ int wclose(int fd)
 	return close(fd);
 }
 
-int wtruncate(const OsPath& pathname, off_t length)
-{
-	return truncate(OsString(pathname).c_str(), length);
-}
-
 int wrename(const OsPath& pathnameOld, const OsPath& pathnameNew)
 {
 	return rename(OsString(pathnameOld).c_str(), OsString(pathnameNew).c_str());

source/lib/sysdep/os/win/wposix/waio.h

@@ -1,4 +1,4 @@
-/* Copyright (C) 2025 Wildfire Games.
+/* Copyright (C) 2026 Wildfire Games.
  *
  * Permission is hereby granted, free of charge, to any person obtaining
  * a copy of this software and associated documentation files (the
@@ -130,7 +130,7 @@ extern Status waio_close(int fd);
 // @param size is rounded up to a multiple of maxSectorSize (required by
 // SetEndOfFile; this could be avoided by using the undocumented
 // NtSetInformationFile or SetFileInformationByHandle on Vista and later).
-// use wtruncate after I/O is complete to chop off the excess padding.
+// use truncate after I/O is complete to chop off the excess padding.
 //
 // NB: writes that extend a file (i.e. ALL WRITES when creating new files)
 // are synchronous, which prevents overlapping I/O and other work.

source/lib/sysdep/os/win/wposix/wfilesystem.cpp

@@ -131,21 +131,6 @@ int wclose(int fd)
 }
 
 
-
-int wtruncate(const OsPath& pathname, off_t length)
-{
-	// (re-open the file to avoid the FILE_FLAG_NO_BUFFERING
-	// sector-alignment restriction)
-	HANDLE hFile = CreateFileW(OsString(pathname).c_str(), GENERIC_WRITE, 0, 0, OPEN_EXISTING, 0, 0);
-	ENSURE(hFile != INVALID_HANDLE_VALUE);
-	LARGE_INTEGER ofs; ofs.QuadPart = length;
-	WARN_IF_FALSE(SetFilePointerEx(hFile, ofs, 0, FILE_BEGIN));
-	WARN_IF_FALSE(SetEndOfFile(hFile));
-	WARN_IF_FALSE(CloseHandle(hFile));
-	return 0;
-}
-
-
 OsPath wrealpath(const OsPath& pathname)
 {
 	wchar_t resolved[PATH_MAX];