FileSystemFilter: store the value of includeHidden in prepareSearch()

Since we don't guarantee the synchronization between a call
to openConfigDialog() and matchesFor(), it may happen that
these two methods are called simultaneously by two different
threads. In theory, the value of m_includeHidden may be changed
in gui thread by a call to openConfigDialog(), while at the same
time it may be read in other thread, inside matchesFor().
As a safe solution we make a copy of this value inside prepareSearch()
and use the copy later in matchesFor().

Change-Id: I83fb184ff1914e4c02ee799464ff0d89350ab49c
Reviewed-by: Eike Ziller <eike.ziller@qt.io>

src/plugins/coreplugin/locator/filesystemfilter.cpp

@@ -74,6 +74,7 @@ void FileSystemFilter::prepareSearch(const QString &entry)
 {
     Q_UNUSED(entry)
     m_currentDocumentDirectory = DocumentManager::fileDialogInitialDirectory();
+    m_currentIncludeHidden = m_includeHidden;
 }
 
 QList<LocatorFilterEntry> FileSystemFilter::matchesFor(QFutureInterface<LocatorFilterEntry> &future,
@@ -92,7 +93,7 @@ QList<LocatorFilterEntry> FileSystemFilter::matchesFor(QFutureInterface<LocatorF
     const QDir dirInfo(directory);
     QDir::Filters dirFilter = QDir::Dirs|QDir::Drives|QDir::NoDot|QDir::NoDotDot;
     QDir::Filters fileFilter = QDir::Files;
-    if (m_includeHidden) {
+    if (m_currentIncludeHidden) {
         dirFilter |= QDir::Hidden;
         fileFilter |= QDir::Hidden;
     }

src/plugins/coreplugin/locator/filesystemfilter.h

@@ -56,6 +56,7 @@ private:
     static MatchLevel matchLevelFor(const QRegularExpressionMatch &match, const QString &matchText);
 
     bool m_includeHidden = true;
+    bool m_currentIncludeHidden = true;
     QString m_currentDocumentDirectory;
 };