os: support blocking functions on Windows

Use the GetNamedPipeHandleState and SetNamedPipeHandleState Win32 API functions to add support for os.get_blocking and os.set_blocking.

Author: RayyanAnsari

Include/internal/pycore_fileutils.h

@@ -160,11 +160,10 @@ PyAPI_FUNC(int) _Py_set_inheritable_async_safe(int fd, int inheritable,
 
 PyAPI_FUNC(int) _Py_dup(int fd);
 
-#ifndef MS_WINDOWS
 PyAPI_FUNC(int) _Py_get_blocking(int fd);
 
 PyAPI_FUNC(int) _Py_set_blocking(int fd, int blocking);
-#else   /* MS_WINDOWS */
+#ifdef MS_WINDOWS
 PyAPI_FUNC(void*) _Py_get_osfhandle_noraise(int fd);
 
 PyAPI_FUNC(void*) _Py_get_osfhandle(int fd);

Modules/clinic/posixmodule.c.h

@@ -13929,7 +13929,6 @@ os_set_handle_inheritable_impl(PyObject *module, intptr_t handle,
 }
 #endif /* MS_WINDOWS */
 
-#ifndef MS_WINDOWS
 /*[clinic input]
 os.get_blocking -> bool
     fd: int
@@ -13977,7 +13976,6 @@ os_set_blocking_impl(PyObject *module, int fd, int blocking)
         return NULL;
     Py_RETURN_NONE;
 }
-#endif   /* !MS_WINDOWS */
 
 
 /*[clinic input]

Modules/posixmodule.c

@@ -2450,6 +2450,41 @@ _Py_set_blocking(int fd, int blocking)
     return -1;
 }
 #else   /* MS_WINDOWS */
+int
+_Py_get_blocking(int fd)
+{
+    HANDLE handle;
+    DWORD mode;
+
+    handle = _Py_get_osfhandle(fd);
+    if (handle == INVALID_HANDLE_VALUE)
+        return -1;
+
+    if (!GetNamedPipeHandleState(handle, &mode, NULL, NULL, NULL, NULL, NULL, NULL)) {
+        PyErr_SetFromWindowsErr(0);
+        return -1;
+    }
+    return mode == PIPE_WAIT;
+}
+
+int
+_Py_set_blocking(int fd, int blocking)
+{
+    HANDLE handle;
+    DWORD mode;
+
+    handle = _Py_get_osfhandle(fd);
+    if (handle == INVALID_HANDLE_VALUE)
+        return -1;
+
+    mode = blocking ? PIPE_WAIT : PIPE_NOWAIT;
+    if (!SetNamedPipeHandleState(handle, &mode, NULL, NULL)) {
+        PyErr_SetFromWindowsErr(0);
+        return -1;
+    }
+    return 0;
+}
+
 void*
 _Py_get_osfhandle_noraise(int fd)
 {