utimens: support for native Windows

[Bruno Haible]

With this patch, the test suite of utimens and fdutimens passes
on native Windows (mingw and MSVC 14). Some tests say "SKIP" rather than
"PASS" because symbolic links are not supported (just cosmetics).


2017-04-30  Bruno Haible  <address@hidden>

        utimens: Add support for native Windows.
        * lib/utimens.c: Include <windows.h>, msvc-nothrow.h.
        (fdutimens): Provide a native Windows implementation, like utime.c with
        added tv_nsec support.
        * modules/utimens (Depends-on): Add msvc-nothrow, utime.
        Suggested by Tim Rühsen <address@hidden>.

diff --git a/lib/utimens.c b/lib/utimens.c
index 3b45119..0b3b8e2 100644
--- a/lib/utimens.c
+++ b/lib/utimens.c
@@ -35,6 +35,12 @@
 #include "stat-time.h"
 #include "timespec.h"
 
+#if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__
+# define WIN32_LEAN_AND_MEAN
+# include <windows.h>
+# include "msvc-nothrow.h"
+#endif
+
 /* Avoid recursion with rpl_futimens or rpl_utimensat.  */
 #undef futimens
 #undef utimensat
@@ -271,6 +277,82 @@ fdutimens (int fd, char const *file, struct timespec const 
timespec[2])
   lutimensat_works_really = -1;
 #endif /* HAVE_UTIMENSAT || HAVE_FUTIMENS */
 
+#if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__
+  /* On native Windows, use SetFileTime(). See
+     <https://msdn.microsoft.com/en-us/library/ms724933.aspx>
+     <https://msdn.microsoft.com/en-us/library/ms724284.aspx>  */
+  if (0 <= fd)
+    {
+      HANDLE handle;
+      FILETIME current_time;
+      FILETIME last_access_time;
+      FILETIME last_write_time;
+
+      handle = (HANDLE) _get_osfhandle (fd);
+      if (handle == INVALID_HANDLE_VALUE)
+        {
+          errno = EBADF;
+          return -1;
+        }
+
+      if (ts == NULL || ts[0].tv_nsec == UTIME_NOW || ts[1].tv_nsec == 
UTIME_NOW)
+        {
+          /* GetSystemTimeAsFileTime
+             <https://msdn.microsoft.com/en-us/library/ms724397.aspx>.
+             It would be overkill to use
+             GetSystemTimePreciseAsFileTime
+             <https://msdn.microsoft.com/en-us/library/hh706895.aspx>.  */
+          GetSystemTimeAsFileTime (&current_time);
+        }
+
+      if (ts == NULL || ts[0].tv_nsec == UTIME_NOW)
+        {
+          last_access_time = current_time;
+        }
+      else if (ts[0].tv_nsec == UTIME_OMIT)
+        {
+          last_access_time.dwLowDateTime = 0;
+          last_access_time.dwHighDateTime = 0;
+        }
+      else
+        {
+          ULONGLONG time_since_16010101 =
+            (ULONGLONG) ts[0].tv_sec * 10000000 + ts[0].tv_nsec / 100 + 
116444736000000000LL;
+          last_access_time.dwLowDateTime = (DWORD) time_since_16010101;
+          last_access_time.dwHighDateTime = time_since_16010101 >> 32;
+        }
+
+      if (ts == NULL || ts[1].tv_nsec == UTIME_NOW)
+        {
+          last_write_time = current_time;
+        }
+      else if (ts[1].tv_nsec == UTIME_OMIT)
+        {
+          last_write_time.dwLowDateTime = 0;
+          last_write_time.dwHighDateTime = 0;
+        }
+      else
+        {
+          ULONGLONG time_since_16010101 =
+            (ULONGLONG) ts[1].tv_sec * 10000000 + ts[1].tv_nsec / 100 + 
116444736000000000LL;
+          last_write_time.dwLowDateTime = (DWORD) time_since_16010101;
+          last_write_time.dwHighDateTime = time_since_16010101 >> 32;
+        }
+
+      if (SetFileTime (handle, NULL, &last_access_time, &last_write_time))
+        return 0;
+      else
+        {
+          #if 0
+          DWORD sft_error = GetLastError ();
+          fprintf (stderr, "utime SetFileTime error 0x%x\n", (unsigned int) 
sft_error);
+          #endif
+          errno = EINVAL;
+          return -1;
+        }
+    }
+#endif
+
   /* The platform lacks an interface to set file timestamps with
      nanosecond resolution, so do the best we can, discarding any
      fractional part of the timestamp.  */
diff --git a/modules/utimens b/modules/utimens
index c8167ce..dbe24df 100644
--- a/modules/utimens
+++ b/modules/utimens
@@ -14,11 +14,13 @@ fcntl-h
 fstat
 lstat
 gettime
+msvc-nothrow
 stat-time
 stdbool
 sys_stat
 sys_time
 time
+utime
 utime-h
 
 configure.ac: