7e7b502e36
QFileSystemModel uses a QFileInfoGatherer, which is a QThread, to populate itself with the data from the file system. Some of the system calls we make for that might block, e.g. on Windows a disconnected network can easily result in 10 minutes of timeout. Destroying the QFileSystemModel destroyed the QFileInfoGatherer class member instance, and the QFileInfoGatherer destructor, being a QThread, had to wait on itself to avoid QThread asserting when being destroyed while still running. This means that shutting down a Qt application that was using a QFileSystemModel, e.g. through the non-native QFileDialog, would hang practically indefinitely instead of shutting down. To fix this, explicitly manage the life-time of the QFileInfoGatherer. Manage it in QFileSystemModel through a std::unique_ptr instead of as a direct class member so that we can control its destruction. In the QFileSystemModel destructor, signal the gather to terminate and wait one it for one second. If that fails, schedule the gatherer for later deletion through deleteLater(), and release it from the unique_ptr. The QFileInfoGatherer instance might then be alive with the QFileSystemModel destroyed. When it receives the DeferredDelete event, try again to abort the process and wait on the thread, this time for 5 seconds. If that also fails, then we have to make a choice. We cannot destroy the QThread object while it's still running, so we have to either wait indefinitely, terminate the thread, or accept a memory leak by ignoring the deferred delete event. If the QCoreApplication is shutting down, then we terminate the thread. To make this safe, explicitly control when termination is allowed in the thread - disallow it while the thread is holding a mutex, allow it while the thread is performing I/O operations. If the QCoreApplication is not shutting down, then we connect to the QThread::finished signal, and delete the object in response to that. This might or might not happen, in which case we have to accept that there's a memory leak. Fixes: QTBUG-120062 Change-Id: I1e4243265879d61cf406b4eeb0b11b9d59b006ad Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org> Reviewed-by: Mårten Nordheim <marten.nordheim@qt.io> (cherry picked from commit 0786c17bbc556a0f494fc825af47c604a9dc0241) Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org> (cherry picked from commit 4c864a0e89f786491512ffa20de8a0a879cf1d58)