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Dieter Mayer
96f6fa44ad
QHash/QMap::keys() allocates a list of every key on each call, then contains() searches it linearly - an accidental O(n) plus allocation where a direct O(1) lookup was meant. 35 occurrences across 7 files, found while profiling project load times (context: #553/#560). The hot one is ElementPictureFactory::getPictures(), which runs once per element instance on project load: on the 3399 KiB example project (191 instances, 129 cache hits) the keys() detour cost 45 ms of the 1.34 s total - measured, not estimated; the fix reproducibly shaves ~35-45 ms off that load. The remaining call sites are UI paths (search&replace, dynamic text model, undo commands) where the waste scales with selection/model size. No behavior change: for QHash/QMap, keys().contains(k) and contains(k) are equivalent by definition. (cherry picked from commit 0a7f8f072fa68de7c01a9fc134a4bc8e16d62062)