# HG changeset patch
# User Steve Borho <steve@borho.org>
# Date 1399106034 -7200
# Node ID 4898c37e03c0b804d6ca8c3ad341dceb53ff5806
# Parent  cadad384c97c7956c98f3c9b92d8cc40fa16d93b
win32: backout 1a9ebc83a74c

This change conflicted with TortoiseHg's use of QFileSystemWatcher. Files which
were being monitored (for file-system events) were unable to be reliably updated
using util.atomictempfile.  Often the update would error out in the middle of
the process leaving neither the old or the new file in place.

My guess is that _kernel32.CreateFileA() is triggering an exception that is
not handled correctly within unlink()

diff -r cadad384c97c -r 4898c37e03c0 mercurial/win32.py
--- a/mercurial/win32.py	Thu May 01 17:48:02 2014 -0500
+++ b/mercurial/win32.py	Sat May 03 10:33:54 2014 +0200
@@ -25,7 +25,6 @@
 # GetLastError
 _ERROR_SUCCESS = 0
 _ERROR_NO_MORE_FILES = 18
-_ERROR_SHARING_VIOLATION = 32
 _ERROR_INVALID_PARAMETER = 87
 _ERROR_INSUFFICIENT_BUFFER = 122
 
@@ -61,9 +60,7 @@
 
 _OPEN_EXISTING = 3
 
-_FILE_FLAG_OPEN_REPARSE_POINT = 0x00200000
 _FILE_FLAG_BACKUP_SEMANTICS = 0x02000000
-_FILE_FLAG_DELETE_ON_CLOSE = 0x04000000
 
 # SetFileAttributes
 _FILE_ATTRIBUTE_NORMAL = 0x80
@@ -424,18 +421,11 @@
 def unlink(f):
     '''try to implement POSIX' unlink semantics on Windows'''
 
-    # If we can open f exclusively, no other processes must have open handles
-    # for it and we can expect its name will be deleted immediately when we
-    # close the handle unless we have another in the same process.  We also
-    # expect we shall simply fail to open f if it is a directory.
-    fh = _kernel32.CreateFileA(f, 0, 0, None, _OPEN_EXISTING,
-        _FILE_FLAG_OPEN_REPARSE_POINT | _FILE_FLAG_DELETE_ON_CLOSE, None)
-    if fh != _INVALID_HANDLE_VALUE:
-        _kernel32.CloseHandle(fh)
-        return
-    error = _kernel32.GetLastError()
-    if error != _ERROR_SHARING_VIOLATION:
-        raise ctypes.WinError(error)
+    if os.path.isdir(f):
+        # use EPERM because it is POSIX prescribed value, even though
+        # unlink(2) on directories returns EISDIR on Linux
+        raise IOError(errno.EPERM,
+                      "Unlinking directory not permitted: '%s'" % f)
 
     # POSIX allows to unlink and rename open files. Windows has serious
     # problems with doing that: