On Apple operating systems where the app runs in a sandbox, the application can not access files outside of its sandbox without explicit user approval. This applies to iOS and friends, as well as optionally for macOS (when the sandbox is enabled, which is a requirement for publishing apps to the macOS App Store). When the user gives explicit access to a file or directory, we need to manage this access at runtime by starting and stopping the access via startAccessingSecurityScopedResource and stopAccessingSecurityScopedResource, and these functions must be balanced, to avoid leaking kernel resources. The access unfortunately doesn't persist automatically when the application terminates (unlike takePersistableUriPermission on Android), so we have to manually persist the access via security scoped bookmarks. We store these inside the app's own sandbox, in a way that limits the access to only that application, so persisting them on behalf of the user should be fine. The persisted bookmarks are loaded in the background on application start, ready for when the application wants to open earlier accessed file or directories. [ChangeLog][Apple] Sandboxed applications on Apple platforms, (including macOS if opted in to) can now access files outside of the application sandbox (so called security scoped resources) for both reading and writing. Files or folders chosen by the user via file dialogs or similar native mechanism are automatically and transparently handled, including persistent access across application and device restarts. Fixes: QTBUG-120528 Task-number: QTBUG-117832 Task-number: QTBUG-120528 Task-number: QTBUG-141414 Change-Id: I90d94066cbf7cd74750049d5d1b990917fd10cad Reviewed-by: Doris Verria <doris.verria@qt.io>