path: root/mkspecs/win32-msvc11
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authorMarc Mutz <>2023-01-13 10:11:46 +0100
committerMarc Mutz <>2023-01-26 17:44:19 +0100
commitcde904b38ab6ef1ddcc9a0cbcae766cf42d58d81 (patch)
treedc365ecc97262192317a5935448640ee2d227c43 /mkspecs/win32-msvc11
parentce9d708d514011db1ab45630c95222d2a30c7550 (diff)
Q<Typed>Permission: don't use external stateHEADdev
There's no point in using the full implicit sharing machinery when the type's state consists of two enums, a bool or, indeed, if the type has no state at all. QRect has more state and isn't implicitly shared. To remain extensible in the future, all that is required is that the type contains space for an eventual d-pointer and that all access to members (except swapping, and, as a consequence, the move SFMs, but including the copy SMFs, ctors and dtor) is confined to out-of-line functions. So define a ShortData (name stolen from QDateTime) nested struct in each of the stateful Q<Typed>Permission classes, of the same size as a pointer, holding the trivially-relocatable fields we currently have. If, in the future, fields are added such that the reserved[] space in any given class' ShortData no longer suffices to hold them, or said fields are not of Q_RELOCATABLE_TYPE, then the full d-pointer pattern (with an actually defined Private, and detach()ing) can be implemented _for that one class_. The new-style classes are externally indistinguishable from the implicitly-shared old-style ones, just a lot more efficient. Inline the move-ctor, now that we can. This doesn't break encapsulation, even when we eventually activate the d-pointer. As a drive-by, drop the noexcept on the dtors - dtors are implicitly noexcept, anyway. Pick-to: 6.5 Change-Id: Id90a39227277c6554ddd5895e8205485da1e39ca Reviewed-by: Qt CI Bot <> Reviewed-by: Giuseppe D'Angelo <> Reviewed-by: Tor Arne Vestbø <>
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