Merge pull request #2004 from pared/refactor_windows_constants

use windows constants in system.py

dvc/system.py

@@ -138,15 +138,16 @@ class System(object):
         import ctypes
         from ctypes import c_void_p, c_wchar_p, Structure, WinError, POINTER
         from ctypes.wintypes import DWORD, HANDLE, BOOL
+        from win32file import (
+            FILE_FLAG_BACKUP_SEMANTICS,
+            FILE_FLAG_OPEN_REPARSE_POINT,
+            FILE_SHARE_READ,
+            OPEN_EXISTING,
+        )
 
-        # NOTE: use this flag to open symlink itself and not the target
-        # See https://docs.microsoft.com/en-us/windows/desktop/api/
+        # NOTE: use FILE_FLAG_OPEN_REPARSE_POINT to open symlink itself and not
+        # the target See https://docs.microsoft.com/en-us/windows/desktop/api/
         # fileapi/nf-fileapi-createfilew#symbolic-link-behavior
-        FILE_FLAG_OPEN_REPARSE_POINT = 0x00200000
-
-        FILE_FLAG_BACKUP_SEMANTICS = 0x02000000
-        FILE_SHARE_READ = 0x00000001
-        OPEN_EXISTING = 3
 
         class FILETIME(Structure):
             _fields_ = [("dwLowDateTime", DWORD), ("dwHighDateTime", DWORD)]
@@ -237,8 +238,7 @@ class System(object):
         from ctypes.wintypes import DWORD, HANDLE
 
         # https://docs.microsoft.com/en-us/windows/desktop/api/synchapi/nf-synchapi-waitforsingleobject
-        WAIT_OBJECT_0 = 0
-        WAIT_TIMEOUT = 0x00000102
+        from win32event import WAIT_OBJECT_0, WAIT_TIMEOUT
 
         func = ctypes.windll.kernel32.WaitForSingleObject
         func.argtypes = [HANDLE, DWORD]
@@ -272,7 +272,7 @@ class System(object):
 
         # https://docs.microsoft.com/en-us/windows/desktop/fileio/
         # file-attribute-constants
-        FILE_ATTRIBUTE_REPARSE_POINT = 0x400
+        from winnt import FILE_ATTRIBUTE_REPARSE_POINT
 
         if os.path.lexists(path):
             info = System.getdirinfo(path)