* 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
Something interesting going on here with ARC / Objective-C++ that we are investigating and will re-land.
This reverts commit c90ed08d1073701e2c7f8a2677d460c140f05264.
* 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
* Fixed bug in `ASEnvironmentMergeObjectAndState`
* New ASLayoutSpec methods for `setChild`/`setChildren`/`setChild:forIdentifier:` have been added to take in a trait collection.
* Added `setChild:`-like methods for ASLayoutSpecs take a traitCollection
* Fixed instances where nodes in a data controller were not getting their trait collections
* propagate traitCollection in ASDisplayNode on insertSubnode or addSubnode
- 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)
1) Set the ascender/descender of an ASTextNode when the attributeString is set. Previously ascender/descender were only being computed in `setValuesFromLayoutable` and only when the attribute string was not nil. May make sense to remove the computation from `setValuesFromLayoutable` entirely.
2) Remove ability to allow different children of a stack spec to aling to different baselines. This wasn't working before and I'm not convinced it is possible to do properly/useful enough to invest the time.
3) Have all stack spec run `ASStackBaselinePositionedLayout::compute` to compute the stack's ascender and descender. Even if the stack isn't aligning its children to a baseline, the stack itself may be a child of another stack that IS aligning to a baseline.
- constrainedSizeForCalculatedLayout is of type ASSizeRange.
- calculatedLayout is better explained.
- Since ASLayout is cached and reused, its position property is mutable.
