Deprecate usage of qt_ntfs_permission_lookup

With the introduction of a new atomic variable the users should use the
class QNtfsPermissionCheckGuard or the helper functions
- qEnableNtfsPermissionChecks()
- qDisableNtfsPermissionChecks()
- qAreNtfsPermissionChecksEnabled()
to enable/disable permission checks instead of manually managing the
variable qt_ntfs_permission_lookup (which is a non-atomic variable and
as such prone to data races).

Also moved the variable qt_ntfs_permission_lookup to qfile.h to make it
clash with the user-side declarations the documentation suggested to
use (and it is probably also a better fit thematically anyway).

[ChangeLog][QtCore][Deprecation Notice] Deprecated the variable
qt_ntfs_permission_lookup to avoid race conditions while enabling or
disabling permission checks. It can be replaced by the RAII class
QNtfsPermissionCheckGuard or with the functions
qEnableNtfsPermissionChecks(), qDisableNtfsPermissionChecks() and
qAreNtfsPermissionChecksEnabled().

Fixes: QTBUG-105804
Change-Id: I93a563864ffb3f9945551c34004d8ca393603b25
Reviewed-by: Marc Mutz <marc.mutz@qt.io>

1 files changed, 6 insertions, 0 deletions

diff --git a/src/corelib/io/qfile.h b/src/corelib/io/qfile.h
index f608ca48f5..cb06665a9f 100644
--- a/src/corelib/io/qfile.h
+++ b/src/corelib/io/qfile.h
@@ -27,6 +27,12 @@ namespace std {
 QT_BEGIN_NAMESPACE
 
 #ifdef Q_OS_WIN
+
+#if QT_DEPRECATED_SINCE(6,6)
+QT_DEPRECATED_VERSION_X_6_6("Use QNtfsPermissionCheckGuard RAII class instead.")
+Q_CORE_EXPORT extern int qt_ntfs_permission_lookup;      // defined in qfilesystemengine_win.cpp
+#endif
+
 Q_CORE_EXPORT bool qEnableNtfsPermissionChecks() noexcept;
 Q_CORE_EXPORT bool qDisableNtfsPermissionChecks() noexcept;
 Q_CORE_EXPORT bool qAreNtfsPermissionChecksEnabled() noexcept;