* Revert "Revert "[ASLayoutSpec] Use childrenMap directly to prevent creating an NSArray within ASDK (#1937)""
This reverts commit 735b4ebd0872483044d98a5d05b43324e76fc8d4.
* Fix crash and add exception for mutating while using fast enumeration of ASLayoutSpec children
NSFastEnumeration is potentially quite dangerous in the wrong hands. In particular, it does not provide a safe mechanism for you to return temporary objects directly, and it does not provide any guarantee that you will be called when the enumeration has completed; therefore if we generate temporaries and store them in an instance variable, we will not necessarily be able to clean them up! This means fast enumeration methods should never be called within an autorelease pool or the autorelease pool be drained within the fast enumeration loop.
The reason is we store references to objects in the stackBuf struct by casting the child pointer to __autoreleasing id. If we pop the autorelease pool between calls to -countByEnumeratingWithState:objects:count:, it will die in a messy explosion of pointer dereferences and EXC_BAD_ACCESS.
* Add tests for ASDisplayNode and ASLayoutSpec fast enumeration
* Use childrenMap directly to prevent creating an NSArray in ASDK for ASLayoutSpec children
* Add locking for parent property in ASLayoutSpec
* Remove unnecessary import
* Add newline
* Add NSFastEnumeration to ASEnvironment and ASDisplayNode / ASLayoutSpec
* Change NSMutableArray initializer to arrayWithCapacity:
* Move ASLayoutSpec+Private.h into Private folder
Fixes building with Swift
* Remove lock for ASLayoutSpec parent
Passing around a pointer was leading to crashes as the ASVC was the sole owner of the context. There are cases where the VC would dealloc while its subnodes were laying out. This could lead to the subnodes accessing a garbage pointer.
* make variable naming reflect ASEnvironmentTraitCollection vs ASTraitCollection
* move trait propagation to cell allocation instead of via a nested block
* move trait propagation when setting a displaynode's supernode instead of when adding a subnode
* fixed misspelling of "colection"
Initial attempt to get display traits working with ASEnvironment.
To get proper ASDisplayTraits support, you must use an ASViewController. The ASViewController implements UITraitCollection-related methods (`traitCollectionDidChange:`, `willTransitionToTraitCollection:withTransitionCoordinator:`, viewWillTransitionToSize:withTransitionCoordinator`) to update the internal ASDisplayTraits and propagate them to subnodes.
ASTableNode and ASCollectionNode don't actually have their cells as subnodes, so a little bit of trickery is involved (on `setEnvironment:` the table/collection node gets its data controllers completedNodes and propagates the new traits. see `ASDisplayTraitsCollectionTableSetEnvironmentState`). The data controller also passes the current display traits when creating new cells.
ASViewController also supports the ability to return a custom set of display traits. So if you have a modal dialog that should always be told it is in a compact size class, you can set the override block before displaying the VC.
A new example, called Display Traits, has been added. It shows how display traits can be used in a ASViewController with a normal ASDisplayNode as its root, as well as in ASViewControllers hosting table nodes and collection nodes. There is also an example of overriding the default display traits of a VC.
Please provide feedback!
- Refactor naming of ASEnvironmentCollection to ASEnvironmentState
- Remove struct pointers
- Move ASEnvironmentStatePropagation to a enum class
- Move merge functions to pure functions
- Move ASLayoutOptionsForwarding and ASLayoutableExtensibility into ASLayoutSpec and ASDisplayNode
- Remove ASLayoutableSetValuesForLayoutable and move into explicit classes (ASDisplayNode, ASTextNode)
