perf(discovery): reduce per-file allocations in discovery phase#9991
perf(discovery): reduce per-file allocations in discovery phase#9991qoole wants to merge 1 commit into
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- Replace QString::split('.') with indexOf/lastIndexOf to extract
basename and extension without allocating a QList<QString> per file.
- Use QStringView for the basename and extension slices so the
comparisons against forbiddenFilenames / forbiddenBasenames /
forbiddenExtensions run against zero-copy views into the original
QString rather than allocating new QString copies.
- Replace 5 QTimer::singleShot(0, ...) calls with
QMetaObject::invokeMethod(Qt::QueuedConnection) which achieves the
same deferred invocation without allocating a QTimer on the heap
each time. In a large sync with many directories, this eliminates
thousands of unnecessary heap allocations.
Signed-off-by: Qoole <2862661+qoole@users.noreply.github.com>
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Summary
Three micro-optimizations to the discovery hot path that fire once per file/directory in a sync. With large folder trees these allocations add up to noticeable GC and heap churn.
Changes
QString::split('.')allocates aQList<QString>plus copies for each segment, just to recover the basename and extension. Replaced withindexOf/lastIndexOfto find the cut points directly.QStringViewslices into the originalQStringrather than allocating new ownedQStringcopies. The downstream forbidden-filename / forbidden-basename / forbidden-extension comparisons all compare againstQStringView-compatible data, so no copies are needed.QTimer::singleShot(0, ...)call sites in discovery were replaced withQMetaObject::invokeMethod(Qt::QueuedConnection). Both schedule a slot for the next event loop iteration, but the latter does not allocate aQTimerobject on the heap. In a large sync with many directories this eliminates thousands ofQTimerallocations.Behavior is unchanged — same parsing results, same scheduling semantics.
Checklist
AI (if applicable)