Revert "Remove _cygwin.posix_to_win()"

This reverts commit 8b31718.

tests/test_winrt.py

@@ -1,9 +1,10 @@
 import asyncio
+import sys
 import unittest
 from concurrent.futures import Future
 from pathlib import Path
 
-from win32more import FAILED, POINTER, WINFUNCTYPE, Byte, Char, Int32, UInt32, VoidPtr, WinError, cast, pointer
+from win32more import FAILED, POINTER, WINFUNCTYPE, Byte, Int32, UInt32, VoidPtr, WinError, cast, pointer
 from win32more._winrt import (
     ReceiveArray,
     _ro_get_parameterized_type_instance_iid,
@@ -21,23 +22,16 @@
 from win32more.Windows.System import DispatcherQueueController
 from win32more.Windows.System.Threading import ThreadPool
 from win32more.Windows.Win32.Foundation import HRESULT, S_OK
-from win32more.Windows.Win32.Storage.FileSystem import GetFullPathName
 from win32more.Windows.Win32.System.Com import CoTaskMemAlloc, IUnknown
 from win32more.Windows.Win32.System.Threading import GetCurrentThreadId
 from win32more.Windows.Win32.System.WinRT import RO_INIT_MULTITHREADED, IInspectable, RoInitialize, RoUninitialize
 
+if sys.platform == "cygwin":
+    from win32more._cygwin import posix_to_win
+else:
 
-# Workaround for cygwin.
-# Path.resolve() returns cygwin path and Windows API doesn't work with it.
-def _abspath(relpath: str) -> str:
-    size = GetFullPathName(relpath, 0, None, None)
-    if size == 0:
-        raise WinError()
-    buf = (Char * size)()
-    r = GetFullPathName(relpath, size, buf, None)
-    if r == 0:
-        raise WinError()
-    return buf.value
+    def posix_to_win(path):
+        return path
 
 
 class TestWinrt(unittest.TestCase):
@@ -64,7 +58,7 @@ def test_stringmap(self):
 
     def test_readfile(self):
         async def winrt_readfile():
-            storage_file = await StorageFile.GetFileFromPathAsync(_abspath(__file__))
+            storage_file = await StorageFile.GetFileFromPathAsync(posix_to_win(__file__))
             return await FileIO.ReadTextAsync(storage_file)
 
         text1 = asyncio.run(winrt_readfile())
@@ -74,7 +68,7 @@ async def winrt_readfile():
 
     def test_readfile2(self):
         async def winrt_readfile():
-            return await PathIO.ReadTextAsync(_abspath(__file__))
+            return await PathIO.ReadTextAsync(posix_to_win(__file__))
 
         text1 = asyncio.run(winrt_readfile())
         # git clone might change eol format.
@@ -84,7 +78,7 @@ async def winrt_readfile():
 
     def test_fillarray(self):
         async def winrt_readlines():
-            return await PathIO.ReadLinesAsync(_abspath(__file__))
+            return await PathIO.ReadLinesAsync(posix_to_win(__file__))
 
         ivector = asyncio.run(winrt_readlines())
         lines = Path(__file__).read_text().splitlines()
@@ -94,7 +88,7 @@ async def winrt_readlines():
 
     def test_passarray(self):
         async def winrt_readlines():
-            return await PathIO.ReadLinesAsync(_abspath(__file__))
+            return await PathIO.ReadLinesAsync(posix_to_win(__file__))
 
         ivector = asyncio.run(winrt_readlines())
         lines = [str(i) for i in range(10)]

win32more/_cygwin.py

@@ -1,5 +1,5 @@
 import platform
-from ctypes import CFUNCTYPE, POINTER, c_void_p, cast, cdll
+from ctypes import CFUNCTYPE, POINTER, c_char_p, c_uint, c_void_p, c_wchar_p, cast, cdll
 
 if platform.machine() == "x86_64":
     ARCH = "X64"
@@ -33,3 +33,22 @@ def __call__(self, this, *args, **kwargs):
         # WORKAROUND: return_length and return are passed as kwargs.
         _args = list(args) + list(kwargs.values())
         return func(this, *_args)
+
+
+CCP_POSIX_TO_WIN_W = 1
+
+cygwin1 = cdll.LoadLibrary("cygwin1.dll")
+cygwin_create_path = cygwin1.cygwin_create_path
+cygwin_create_path.restype = c_void_p
+cygwin_create_path.argtypes = [c_uint, c_void_p]
+
+free = cygwin1.free
+free.restype = None
+free.argtypes = [c_void_p]
+
+
+def posix_to_win(posix_path: str) -> str:
+    p = cygwin_create_path(CCP_POSIX_TO_WIN_W, c_char_p(posix_path.encode("utf-8")))
+    win_path = c_wchar_p(p).value
+    free(p)
+    return win_path