Summary:
This is a very crucial change, everything else in this stack depends on it.
Here is the set of constraints that we have for ShadowNode-based class hierarchy:
* `ShadowNode` is a base class that defines basic operations on the nodes. It does not have virtual methods by design (virtual dispatch hurts performance; we want to limit and centralize that in `ComponentDescriptor`s).
* `ConcreteShadowNode<>` template *statically* wires particular `ShadowNode` and particular `Props` establishing a type-safe relationship between them ensured on compile time.
* Not all `ShadowNode`s are "layoutable", not all "layoutable" `ShadowNode`s use Yoga to do layout.
* Layotability (and YogaLayotability) feature is implemented as two classes `LayoutableShadowNode` and `YogaLayoutableShadowNode`. These classes essentially need to know something about the ShadowNode nature of the object (get the list of children or replace some children).
Before the change, `LayoutableShadowNode` and `YogaLayoutableShadowNode`classes did not inherit `ShadowNode` because we don't want to use *virtual inheritance* for `ShadowNode`: `ConcreteShadowNode<>` already inherits `ShadowNode`, so if we make `LayoutableShadowNode` inherits `ShadowNode`, we will have to somehow flatten this inheritance hierarchy (and the virtual inheritance is an answer to that). (Yes, C++ supports multiple inheritance and virtual inheritance.)
Before this change, we solved this dilemma this way: We have a subclass-template `ConcreteViewShadowNode<>` that inherits `ConcreteShadowNode<>` and `YogaLayoutableShadowNode`. Then, we had a bunch of methods that implement the rerouting of some functionality from `YogaLayoutableShadowNode` to `ShadowNode` and vise-versa. (See the diagram "Before".)
That worked fine, except the caveats:
* That wiring is nasty, complex, hard to reason about and overall limiting.
* There is no way to statically cast `LayoutableShadowNode` to `ShadowNode` (because there is no common base class). That forces us to use dynamic_cast on some perf critical paths (including layout, diffing and so on).
* Adding features that rely on interop between `LayoutableShadowNode` and `ShadowNode` is a nightmare.
It should be a better way to deal with this dilemma, and this diff implements a different approach: We can have a base class of `ConcreteShadowNode<>` as a template parameter. With this approach, we can make `LayoutableShadowNode` inherit `ShadowNode` and when we need to instantiate a `ConcreteShadowNode<>` that needs to be layoutable, we can just specify `YogaLayoutableShadowNode` as a base class. (See the diagram "After".)
This simple change will allow us to simplify a lot of things. The rest of the stack is about getting rid of unnecessary moving parts. Which will finally allow us to build "Inline Views" feature.
```
╭──────────────────────╮
│ ◎ ○ ○ ░░░░░░░░░░░░░░░│
├──────────────────────┤
│ │
│ │
│ Before │
│ │ ┌────────────────────────────┐ ┌────────────────────────────┐
│ │ │ │ │ │
│ │ │ ShadowNode │ │ LayoutableShadowNode │
└──────────────────────┘ │ │ │ │
└────────────────────────────┘ └────────────────────────────┘
▲ ▲
│ │
╔════════════════════════════╗ ┌────────────────────────────┐
║ ║ │ │
┌────────�║ ConcreteShadowNode<> ║ │ YogaLayoutableShadowNode │
│ ║ ║ │ │
│ ╚════════════════════════════╝ └────────────────────────────┘
│ ▲ ▲
│ │ │
│ │ │
│ │ │
│ │ ╔════════════════════════════╗ │
│ │ ║ ║ │
│ └─────║ ConcreteViewShadowNode<> ║─┘
│ ║ ║
│ ╚════════════════════════════╝
│ ▲
│ │
│ ┌──────────────┴───────────────┐
│ │ │
│ │ │
│ │ │
┌────────────────────────────┐ ┌────────────────────────────┐ ┌────────────────────────────┐
│ │ │ │ │ │
│ TextShadowNode │ │ ViewShadowNode │ │ ParagraphShadowNode │
│ │ │ │ │ │
└────────────────────────────┘ └────────────────────────────┘ └────────────────────────────┘
╭──────────────────────╮
│ ◎ ○ ○ ░░░░░░░░░░░░░░░│
├──────────────────────┤
│ │ ┌────────────────────────────┐
│ │ │ │
│ After │ │ ShadowNode │
│ │ │ │
│ │ └────────────────────────────┘
│ │ ▲
└──────────────────────┘ ┌────────────────────────────────────┤
│ │
│ ╔════════════════════════════╗
┌────────────────────────────┐ ║ ConcreteShadowNode ║
│ │ ║ <Base: ShadowNode> ║
│ LayoutableShadowNode │ ║ ║
│ │ ╚════════════════════════════╝
└────────────────────────────┘ ▲
▲ │
│ ┌────────────────────────────┐
┌────────────────────────────┐ │ │
│ │ │ TextShadowNode │
│ YogaLayoutableShadowNode │ │ │
│ │ └────────────────────────────┘
└────────────────────────────┘
▲
│
╔════════════════════════════╗
║ ConcreteShadowNode ║
║ <Base: ║
║ YogaLayoutableShadowNode> ║
╚════════════════════════════╝
▲
│
╔════════════════════════════╗
║ ║
║ ConcreteViewShadowNode<> ║
║ ║
╚════════════════════════════╝
▲
├─────────────────────────────────────┐
│ │
┌────────────────────────────┐ ┌────────────────────────────┐
│ │ │ │
│ ParagraphShadowNode │ │ ViewShadowNode │
│ │ │ │
└────────────────────────────┘ └────────────────────────────┘
```
Changelog: [Internal] Fabric-specific internal change.
Reviewed By: sammy-SC
Differential Revision: D19963353
fbshipit-source-id: b65c8a5064bdb54ab64f08a8e546aa9e2b5a486b
Summary:
Having automatic defaults/an optional arg for `convertRawProp` has caused way more problems than it is worth. Remove the default argument.
Changelog: [Internal]
Reviewed By: shergin
Differential Revision: D19151594
fbshipit-source-id: 839ec8d138b2c3c083f221a2871582454004648c
Summary: We are moving to more stable APIs removing all mentiones of the effort name from the codebase.
Reviewed By: mdvacca
Differential Revision: D12912894
fbshipit-source-id: 4a0c6b9e7454b8b14e62d419e9e9311dc0c56e7a
Summary:
All code styles are terribly ugly. We have the only choise - choise something and embrace it.
This particular code style was borrowed from a neibour Fabric-friendly project because it follows established Facebook guides and respects client-side traditions.
Reviewed By: mdvacca
Differential Revision: D10218598
fbshipit-source-id: 8c4cf6713c07768566dadef479191661c79988f0
Summary: That should save us some app size kilobytes.
Reviewed By: mdvacca
Differential Revision: D10081499
fbshipit-source-id: 2b950768c609b412f9be332c22b6b1e96657e5ea
Summary: This change drops the year from the copyright headers and the LICENSE file.
Reviewed By: yungsters
Differential Revision: D9727774
fbshipit-source-id: df4fc1e4390733fe774b1a160dd41b4a3d83302a
Summary:
@public
Previously, all ConcreteShadowNode subclasses had to override `getComponentName()` function to specialize a name of the component. And often it was all that those subclasses do. Now, it's a template argument; and many ShadowNode classes can be created as oneliners via *just* specializing ConcreteShadowNode template.
Unfortunately, C++ does not allow to use `std::string`s or string literals as template arguments, but it allows to use pointers. Moreover, those pointers must point to some linked data, hence, those values must be declared in .cpp (not .h) files. For simplicity, we put those constants in Props classes, (but this is not a strong requirement).
Reviewed By: mdvacca
Differential Revision: D8942826
fbshipit-source-id: 4fd517e2485eb8f8c20a51df9b3496941856d8a5
Joshua Gross
Valentin Shergin
Andres Suarez
Héctor Ramos