[RFC PATCH 03/11] include: Add a helper function to test if a status indicates deferred completion.

[Jinoh Kang]

Put it in a separate header file so that it won't pollute everyone's
pre-processor macro definition namespace with ntstatus.h.  Note that
winnt.h omits STATUS_ALERTED.

Signed-off-by: Jinoh Kang <jinoh.kang.kr at gmail.com>
---

Notes:
    This function is used in the subsequent patch.  See its notes.

 include/wine/async.h | 46 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 46 insertions(+)
 create mode 100644 include/wine/async.h

diff --git a/include/wine/async.h b/include/wine/async.h
new file mode 100644
index 00000000000..1ef4ded4319
--- /dev/null
+++ b/include/wine/async.h
@@ -0,0 +1,46 @@
+/*
+ * Common helper definitions for Wine asynchronous I/O
+ *
+ * Copyright (C) 2022 Jinoh Kang
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
+ */
+
+#ifndef __WINE_WINE_ASYNC_H
+#define __WINE_WINE_ASYNC_H
+
+#include <windef.h>
+#include <ntstatus.h>
+
+/* Tests whether the return status of an I/O request server call indicates that
+ * the ownership of async_fileio has been relinquished from the caller and
+ * transferred to the async completion routine.
+ */
+static inline BOOL is_completion_deferred( NTSTATUS status )
+{
+    /* STATUS_ALERTED is a status code internally repurposed in wineserver
+     * to indicate that an APC_ASYNC_IO system APC has been queued to notify
+     * completion of the async.
+     *
+     * We could simply have translated STATUS_ALERTED to STATUS_PENDING in
+     * server side, obviating the need for this function; however,
+     * STATUS_ALERTED does not necessarily mean that the I/O request will be
+     * completed asynchronously (i.e. "async->pending" will be set).
+     * We explicitly differentiate these conditions to avoid confusion.
+     */
+    return status == STATUS_PENDING || status == STATUS_ALERTED;
+}
+
+#endif  /* __WINE_WINE_ASYNC_H */
-- 
2.31.1