implement os.FileInfo.*time_ns for windows

R=golang-dev, adg
CC=golang-dev
https://golang.org/cl/1145044

src/pkg/os/stat_windows.go

@@ -39,9 +39,8 @@ func setFileInfo(fi *FileInfo, name string, fa, sizehi, sizelo uint32, ctime, at
 	fi.Size = int64(sizehi)<<32 + int64(sizelo)
 	fi.Name = name
 	fi.FollowedSymlink = false
-	// TODO(brainman): use ctime atime wtime to prime following FileInfo fields
-	fi.Atime_ns = 0
-	fi.Mtime_ns = 0
-	fi.Ctime_ns = 0
+	fi.Atime_ns = atime.Microseconds() * 1000
+	fi.Mtime_ns = wtime.Microseconds() * 1000
+	fi.Ctime_ns = ctime.Microseconds() * 1000
 	return fi
 }

src/pkg/syscall/syscall_windows.go

@@ -369,16 +369,11 @@ func Ftruncate(fd int, length int64) (errno int) {
 
 func Gettimeofday(tv *Timeval) (errno int) {
 	var ft Filetime
-	// 100-nanosecond intervals since January 1, 1601
 	GetSystemTimeAsFileTime(&ft)
-	t := uint64(ft.HighDateTime)<<32 + uint64(ft.LowDateTime)
-	// convert into microseconds
-	t /= 10
-	// change starting time to the Epoch (00:00:00 UTC, January 1, 1970)
-	t -= 11644473600000000
+	ms := ft.Microseconds()
 	// split into sec / usec
-	tv.Sec = int32(t / 1e6)
-	tv.Usec = int32(t) - tv.Sec
+	tv.Sec = int32(ms / 1e6)
+	tv.Usec = int32(ms) - tv.Sec
 	return 0
 }
 

src/pkg/syscall/zsyscall_windows_386.go

@@ -1,4 +1,4 @@
-// mksyscall_mingw.sh -l32 syscall_mingw.go zsyscall_mingw_386.go
+// mksyscall_windows.sh -l32 syscall_windows.go syscall_windows_386.go
 // MACHINE GENERATED BY THE COMMAND ABOVE; DO NOT EDIT
 
 package syscall

src/pkg/syscall/ztypes_windows_386.go

@@ -113,6 +113,16 @@ type Filetime struct {
 	HighDateTime uint32
 }
 
+func (ft *Filetime) Microseconds() int64 {
+	// 100-nanosecond intervals since January 1, 1601
+	ms := int64(ft.HighDateTime)<<32 + int64(ft.LowDateTime)
+	// convert into microseconds
+	ms /= 10
+	// change starting time to the Epoch (00:00:00 UTC, January 1, 1970)
+	ms -= 11644473600000000
+	return ms
+}
+
 type Win32finddata struct {
 	FileAttributes    uint32
 	CreationTime      Filetime