Use backport of samefile from jaraco.windows to support samefile on Windows on Python 2.7.simple-samefile

2 files changed, 221 insertions, 1 deletions

diff --git a/setuptools_scm/git.py b/setuptools_scm/git.py
index 5e294eb..7fa1b32 100644
--- a/setuptools_scm/git.py
+++ b/setuptools_scm/git.py
@@ -1,8 +1,14 @@
 from .utils import do_ex, trace, has_command
 from .version import meta
-from os.path import isfile, join, samefile
+from os.path import isfile, join
 import warnings
 
+try:
+    from os.path import samefile
+except ImportError:
+    from .win_py31_compat import samefile
+
+
 FILES_COMMAND = 'git ls-files'
 DEFAULT_DESCRIBE = 'git describe --dirty --tags --long --match *.*'
 
diff --git a/setuptools_scm/win_py31_compat.py b/setuptools_scm/win_py31_compat.py
new file mode 100644
index 0000000..82a11eb
--- /dev/null
+++ b/setuptools_scm/win_py31_compat.py
@@ -0,0 +1,214 @@
+"""
+Backport of os.path.samefile for Python prior to 3.2
+on Windows from jaraco.windows 3.8.
+
+DON'T EDIT THIS FILE!
+
+Instead, file tickets and PR's with `jaraco.windows
+<https://github.com/jaraco/jaraco.windows>`_ and request
+a port to setuptools_scm.
+"""
+
+import os
+import nt
+import posixpath
+import ctypes.wintypes
+import sys
+import __builtin__ as builtins
+
+
+##
+# From jaraco.windows.error
+
+def format_system_message(errno):
+	"""
+	Call FormatMessage with a system error number to retrieve
+	the descriptive error message.
+	"""
+	# first some flags used by FormatMessageW
+	ALLOCATE_BUFFER = 0x100
+	FROM_SYSTEM = 0x1000
+
+	# Let FormatMessageW allocate the buffer (we'll free it below)
+	# Also, let it know we want a system error message.
+	flags = ALLOCATE_BUFFER | FROM_SYSTEM
+	source = None
+	message_id = errno
+	language_id = 0
+	result_buffer = ctypes.wintypes.LPWSTR()
+	buffer_size = 0
+	arguments = None
+	bytes = ctypes.windll.kernel32.FormatMessageW(
+		flags,
+		source,
+		message_id,
+		language_id,
+		ctypes.byref(result_buffer),
+		buffer_size,
+		arguments,
+	)
+	# note the following will cause an infinite loop if GetLastError
+	#  repeatedly returns an error that cannot be formatted, although
+	#  this should not happen.
+	handle_nonzero_success(bytes)
+	message = result_buffer.value
+	ctypes.windll.kernel32.LocalFree(result_buffer)
+	return message
+
+
+class WindowsError(builtins.WindowsError):
+	"""
+	More info about errors at
+	http://msdn.microsoft.com/en-us/library/ms681381(VS.85).aspx
+	"""
+
+	def __init__(self, value=None):
+		if value is None:
+			value = ctypes.windll.kernel32.GetLastError()
+		strerror = format_system_message(value)
+		if sys.version_info > (3, 3):
+			args = 0, strerror, None, value
+		else:
+			args = value, strerror
+		super(WindowsError, self).__init__(*args)
+
+	@property
+	def message(self):
+		return self.strerror
+
+	@property
+	def code(self):
+		return self.winerror
+
+	def __str__(self):
+		return self.message
+
+	def __repr__(self):
+		return '{self.__class__.__name__}({self.winerror})'.format(**vars())
+
+
+def handle_nonzero_success(result):
+	if result == 0:
+		raise WindowsError()
+
+
+##
+# From jaraco.windows.api.filesystem
+
+FILE_FLAG_OPEN_REPARSE_POINT = 0x00200000
+FILE_FLAG_BACKUP_SEMANTICS = 0x2000000
+OPEN_EXISTING = 3
+FILE_ATTRIBUTE_NORMAL = 0x80
+FILE_READ_ATTRIBUTES = 0x80
+INVALID_HANDLE_VALUE = ctypes.wintypes.HANDLE(-1).value
+
+
+class BY_HANDLE_FILE_INFORMATION(ctypes.Structure):
+	_fields_ = [
+		('file_attributes', ctypes.wintypes.DWORD),
+		('creation_time', ctypes.wintypes.FILETIME),
+		('last_access_time', ctypes.wintypes.FILETIME),
+		('last_write_time', ctypes.wintypes.FILETIME),
+		('volume_serial_number', ctypes.wintypes.DWORD),
+		('file_size_high', ctypes.wintypes.DWORD),
+		('file_size_low', ctypes.wintypes.DWORD),
+		('number_of_links', ctypes.wintypes.DWORD),
+		('file_index_high', ctypes.wintypes.DWORD),
+		('file_index_low', ctypes.wintypes.DWORD),
+	]
+
+	@property
+	def file_size(self):
+		return (self.file_size_high << 32) + self.file_size_low
+
+	@property
+	def file_index(self):
+		return (self.file_index_high << 32) + self.file_index_low
+
+
+class SECURITY_ATTRIBUTES(ctypes.Structure):
+	_fields_ = (
+		('length', ctypes.wintypes.DWORD),
+		('p_security_descriptor', ctypes.wintypes.LPVOID),
+		('inherit_handle', ctypes.wintypes.BOOLEAN),
+	)
+
+
+LPSECURITY_ATTRIBUTES = ctypes.POINTER(SECURITY_ATTRIBUTES)
+
+
+CreateFile = ctypes.windll.kernel32.CreateFileW
+CreateFile.argtypes = (
+	ctypes.wintypes.LPWSTR,
+	ctypes.wintypes.DWORD,
+	ctypes.wintypes.DWORD,
+	LPSECURITY_ATTRIBUTES,
+	ctypes.wintypes.DWORD,
+	ctypes.wintypes.DWORD,
+	ctypes.wintypes.HANDLE,
+)
+CreateFile.restype = ctypes.wintypes.HANDLE
+
+GetFileInformationByHandle = ctypes.windll.kernel32.GetFileInformationByHandle
+GetFileInformationByHandle.restype = ctypes.wintypes.BOOL
+GetFileInformationByHandle.argtypes = (
+	ctypes.wintypes.HANDLE,
+	ctypes.POINTER(BY_HANDLE_FILE_INFORMATION),
+)
+
+
+##
+# From jaraco.windows.filesystem
+
+def compat_stat(path):
+	"""
+	Generate stat as found on Python 3.2 and later.
+	"""
+	stat = os.stat(path)
+	info = get_file_info(path)
+	# rewrite st_ino, st_dev, and st_nlink based on file info
+	return nt.stat_result(
+		(stat.st_mode,) +
+		(info.file_index, info.volume_serial_number, info.number_of_links) +
+		stat[4:]
+	)
+
+
+def samefile(f1, f2):
+	"""
+	Backport of samefile from Python 3.2 with support for Windows.
+	"""
+	return posixpath.samestat(compat_stat(f1), compat_stat(f2))
+
+
+def get_file_info(path):
+	# open the file the same way CPython does in posixmodule.c
+	desired_access = FILE_READ_ATTRIBUTES
+	share_mode = 0
+	security_attributes = None
+	creation_disposition = OPEN_EXISTING
+	flags_and_attributes = (
+		FILE_ATTRIBUTE_NORMAL |
+		FILE_FLAG_BACKUP_SEMANTICS |
+		FILE_FLAG_OPEN_REPARSE_POINT
+	)
+	template_file = None
+
+	handle = CreateFile(
+		path,
+		desired_access,
+		share_mode,
+		security_attributes,
+		creation_disposition,
+		flags_and_attributes,
+		template_file,
+	)
+
+	if handle == INVALID_HANDLE_VALUE:
+		raise WindowsError()
+
+	info = BY_HANDLE_FILE_INFORMATION()
+	res = GetFileInformationByHandle(handle, info)
+	handle_nonzero_success(res)
+
+	return info