os: fix using Win32-API with TCC32 (#10496)

vlib/os/os_c.v

@@ -779,16 +779,35 @@ pub fn getwd() string {
 pub fn real_path(fpath string) string {
 	mut res := ''
 	$if windows {
-		// GetFullPathName doesn't work with symbolic links,
-		// so if it is not a file, get full path
-		mut fullpath := unsafe { &u16(vcalloc_noscan(max_path_len * 2)) }
-		// TODO: check errors if path len is not enough
-		ret := C.GetFullPathName(fpath.to_wide(), max_path_len, fullpath, 0)
-		if ret == 0 {
-			unsafe { free(fullpath) }
-			return fpath.clone()
+		size := max_path_len * 2
+		// gets handle with GENERIC_READ, FILE_SHARE_READ, 0, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, 0
+		// use C.CreateFile(fpath.to_wide(), 0x80000000, 1, 0, 3, 0x80, 0) instead of  get_file_handle
+		// try to open the file to get symbolic link path
+		file := C.CreateFile(fpath.to_wide(), 0x80000000, 1, 0, 3, 0x80, 0)
+		if file != voidptr(-1) {
+			mut fullpath := unsafe { &u16(vcalloc_noscan(size)) }
+			// https://docs.microsoft.com/en-us/windows/win32/api/fileapi/nf-fileapi-getfinalpathnamebyhandlew
+			final_len := C.GetFinalPathNameByHandleW(file, fullpath, size, 0)
+			C.CloseHandle(file)
+			if final_len < size {
+				rt := unsafe { string_from_wide2(fullpath, final_len) }
+				res = rt[4..]
+			} else {
+				unsafe { free(fullpath) }
+				eprintln('os.real_path() saw that the file path was too long')
+				return fpath.clone()
+			}
+		} else {
+			// if it is not a file C.CreateFile doesn't gets a file handle, use GetFullPath instead
+			mut fullpath := unsafe { &u16(vcalloc_noscan(max_path_len * 2)) }
+			// TODO: check errors if path len is not enough
+			ret := C.GetFullPathName(fpath.to_wide(), max_path_len, fullpath, 0)
+			if ret == 0 {
+				unsafe { free(fullpath) }
+				return fpath.clone()
+			}
+			res = unsafe { string_from_wide(fullpath) }
 		}
-		res = unsafe { string_from_wide(fullpath) }
 	} $else {
 		mut fullpath := vcalloc_noscan(max_path_len)
 		ret := &char(C.realpath(&char(fpath.str), &char(fullpath)))

vlib/os/os_test.v

@@ -342,6 +342,20 @@ fn test_realpath_does_not_absolutize_non_existing_relative_paths() {
 	}
 }
 
+fn test_realpath_absolutepath_symlink() {
+	file_name := 'tolink_file.txt'
+	symlink_name := 'symlink.txt'
+	mut f := os.create(file_name) or { panic(err) }
+	f.close()
+	assert os.symlink(file_name, symlink_name) or { panic(err) }
+	rpath := os.real_path(symlink_name)
+	println(rpath)
+	assert os.is_abs_path(rpath)
+	assert rpath.ends_with(file_name)
+	os.rm(symlink_name) or {}
+	os.rm(file_name) or {}
+}
+
 fn test_tmpdir() {
 	t := os.temp_dir()
 	assert t.len > 0

vlib/os/os_windows.c.v

@@ -9,8 +9,7 @@ import strings
 fn C.CreateSymbolicLinkW(&u16, &u16, u32) int
 
 // See https://docs.microsoft.com/en-us/windows/win32/api/winbase/nf-winbase-createhardlinkw
-// TCC gets builder error
-// fn C.CreateHardLinkW(&u16, &u16, C.SECURITY_ATTRIBUTES) int
+fn C.CreateHardLinkW(&u16, &u16, C.SECURITY_ATTRIBUTES) int
 
 fn C._getpid() int
 
@@ -321,7 +320,7 @@ pub fn execute(cmd string) Result {
 
 pub fn symlink(origin string, target string) ?bool {
 	// this is a temporary fix for TCC32 due to runtime error
-	// TODO: patch TCC32
+	// TODO: find the cause why TCC32 for Windows does not work without the compiletime option
 	$if x64 || x32 {
 		mut flags := 0
 		if is_dir(origin) {
@@ -344,8 +343,6 @@ pub fn symlink(origin string, target string) ?bool {
 }
 
 pub fn link(origin string, target string) ?bool {
-	/*
-	// TODO: TCC gets builder error
 	res := C.CreateHardLinkW(target.to_wide(), origin.to_wide(), C.NULL)
 	// 1 = success, != 1 failure => https://stackoverflow.com/questions/33010440/createsymboliclink-on-windows-10
 	if res != 1 {
@@ -355,12 +352,6 @@ pub fn link(origin string, target string) ?bool {
 		return error('C.CreateHardLinkW reported success, but link still does not exist')
 	}
 	return true
-	*/
-	res := execute('fsutil hardlink create $target $origin')
-	if res.exit_code != 0 {
-		return error(res.output)
-	}
-	return true
 }
 
 pub fn (mut f File) close() {