Grab a strong reference for asyncDataSource and asyncDelegate in ASCollectionView and ASTableView before executing the range update to be sure they are not going away while executing the range update. This can happen in range updates while going back in the view controller hierarchy
- Only update range mode if visibility changes if the node is not range controlled
- Only change explicitly set range mode if ASRangeController becomes visible
- Return interface state for range controller in ASCollectionView and ASTableView based on if the containing node is range managed
- optimized ASRecursivelyFindIndexPathsForMultidimensionalArray() to remove enumerateUsingBlock:
- replaced single project call to ASIndexPathsForMultidimensionalArray() in ASRangeController with ASIndexPathsForTwoDimensionalArray()
Use this array while enumerating ASRangeController instances in response to UIApplication notifications,
as it is possible for these events to trigger the mutation of the ASWeakSet and cause an enumeration error.
Introduces ASLayoutRangeModeVisibleOnly, allowing the preservation of decoded backing stores without any extra padding to
strictly minimize memory usage while supporting immediate re-display of content. Set visible range controllers to this mode
upon app suspend / memory warning, while more aggressively clearing others to the ASLayoutRangeModeLowMemory mode.
By default, when the app is running and recieves a memory warning, we set the range mode for non-visible controllers to
ASLayoutRangeModeVisibleOnly. This is because, unlike in the app suspend case where on app resume we can restore controllers
from LowMemory to VisibleOnly, the memory warning doesn't provide a good opportunity to do this.
A new +Beta API to control this behavior is called +setRangeModeForMemoryWarnings:, as some apps may prefer to use LowMemory
in the memory warning scenario. For these apps, optimal user experience will require manually setting the range mode back
to some larger value as the user navigates the app, or they will encounter controllers that are temporarily blank and need
a moment to re-display their contents as they start to become visible.
The optimization seems correct now, but apps like Pinterest have some core code relying on edit operation
order that is actually not permitted by UIKit (and this diff) but were tolerated previously. We will
re-land this once we have time to adapt the code.
