Fabric iOS: allow using fallback component for unsupported ones

Summary:
This allows an unsupported component to be rendered as a "unimplemented view" for better visualization of which component is missing. It is off by default, but configurable in the component factory.

For now, the layout simply follows regular <View />, which means the width/height etc is based on the react component styling. The side effect is that components with 0 height/width won't show up at all.

Reviewed By: mdvacca

Differential Revision: D14869656

fbshipit-source-id: f31e012fb7dc1c64fcc431ea5aa45079a23a618e

Libraries/Components/UnimplementedViews/UnimplementedNativeView.js

@@ -0,0 +1,29 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ * @format
+ * @flow
+ */
+
+'use strict';
+
+const requireNativeComponent = require('requireNativeComponent');
+
+import type {ViewProps} from 'ViewPropTypes';
+import type {ViewStyleProp} from 'StyleSheet';
+import type {NativeComponent} from 'ReactNative';
+
+type NativeProps = $ReadOnly<{|
+  ...ViewProps,
+  name?: ?string,
+  style?: ?ViewStyleProp,
+|}>;
+
+type UnimplementedViewNativeType = Class<NativeComponent<NativeProps>>;
+
+module.exports = ((requireNativeComponent(
+  'UnimplementedNativeView',
+): any): UnimplementedViewNativeType);

Libraries/Components/UnimplementedViews/UnimplementedNativeViewSchema.js

@@ -0,0 +1,43 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ * @format
+ * @flow
+ */
+
+'use strict';
+
+import type {SchemaType} from '../../../packages/react-native-codegen/src/CodegenSchema.js';
+
+const UnimplementedNativeViewSchema: SchemaType = {
+  modules: {
+    UnimplementedNativeViewSchema: {
+      components: {
+        UnimplementedNativeView: {
+          extendsProps: [
+            {
+              type: 'ReactNativeBuiltInType',
+              knownTypeName: 'ReactNativeCoreViewProps',
+            },
+          ],
+          events: [],
+          props: [
+            {
+              name: 'name',
+              optional: true,
+              typeAnnotation: {
+                type: 'StringTypeAnnotation',
+                default: '',
+              },
+            },
+          ],
+        },
+      },
+    },
+  },
+};
+
+module.exports = UnimplementedNativeViewSchema;

React/Fabric/Mounting/ComponentViews/UnimplementedComponent/RCTUnimplementedNativeComponentView.h

@@ -0,0 +1,18 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+#import <UIKit/UIKit.h>
+
+#import <React/RCTViewComponentView.h>
+
+NS_ASSUME_NONNULL_BEGIN
+
+@interface RCTUnimplementedNativeComponentView : RCTViewComponentView
+
+@end
+
+NS_ASSUME_NONNULL_END

React/Fabric/Mounting/ComponentViews/UnimplementedComponent/RCTUnimplementedNativeComponentView.mm

@@ -0,0 +1,60 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+#import "RCTUnimplementedNativeComponentView.h"
+
+#import <react/components/rncore/EventEmitters.h>
+#import <react/components/rncore/Props.h>
+#import <react/components/rncore/ShadowNodes.h>
+
+using namespace facebook::react;
+
+@implementation RCTUnimplementedNativeComponentView {
+  UILabel *_label;
+}
+
+#pragma mark - RCTComponentViewProtocol
+
++ (ComponentHandle)componentHandle
+{
+  return UnimplementedNativeViewShadowNode::Handle();
+}
+
+- (instancetype)initWithFrame:(CGRect)frame
+{
+  if (self = [super initWithFrame:frame]) {
+    static const auto defaultProps = std::make_shared<const UnimplementedNativeViewProps>();
+    _props = defaultProps;
+
+    CGRect bounds = self.bounds;
+    _label = [[UILabel alloc] initWithFrame:bounds];
+    _label.backgroundColor = [UIColor colorWithRed:1.0 green:0.0 blue:0.0 alpha:0.3];
+    _label.layoutMargins = UIEdgeInsetsMake(12, 12, 12, 12);
+    _label.lineBreakMode = NSLineBreakByWordWrapping;
+    _label.numberOfLines = 0;
+    _label.textAlignment = NSTextAlignmentCenter;
+    _label.textColor = [UIColor whiteColor];
+
+    self.contentView = _label;
+  }
+
+  return self;
+}
+
+- (void)updateProps:(SharedProps)props oldProps:(SharedProps)oldProps
+{
+  const auto &oldViewProps = *std::static_pointer_cast<const UnimplementedNativeViewProps>(oldProps ?: _props);
+  const auto &newViewProps = *std::static_pointer_cast<const UnimplementedNativeViewProps>(props);
+
+  [super updateProps:props oldProps:oldProps];
+
+  if (oldViewProps.name != newViewProps.name) {
+    _label.text = [NSString stringWithFormat:@"'%s' is not Fabric compatible yet.", newViewProps.name.c_str()];
+  }
+}
+
+@end

React/Fabric/Mounting/RCTComponentViewFactory.mm

@@ -17,6 +17,7 @@
 #import "RCTScrollViewComponentView.h"
 #import "RCTSliderComponentView.h"
 #import "RCTSwitchComponentView.h"
+#import "RCTUnimplementedNativeComponentView.h"
 #import "RCTViewComponentView.h"
 
 using namespace facebook::react;
@@ -39,6 +40,7 @@ using namespace facebook::react;
   [componentViewFactory registerComponentViewClass:[RCTActivityIndicatorViewComponentView class]];
   [componentViewFactory registerComponentViewClass:[RCTSliderComponentView class]];
   [componentViewFactory registerComponentViewClass:[RCTSwitchComponentView class]];
+  [componentViewFactory registerComponentViewClass:[RCTUnimplementedNativeComponentView class]];
 
   return componentViewFactory;
 }

ReactCommon/fabric/uimanager/ComponentDescriptorRegistry.cpp

@@ -92,9 +92,12 @@ const ComponentDescriptor &ComponentDescriptorRegistry::at(
 
   auto it = _registryByName.find(unifiedComponentName);
   if (it == _registryByName.end()) {
-    throw std::invalid_argument(
-        ("Unable to find componentDescriptor for " + unifiedComponentName)
-            .c_str());
+    if (_fallbackComponentDescriptor == nullptr) {
+      throw std::invalid_argument(
+          ("Unable to find componentDescriptor for " + unifiedComponentName)
+              .c_str());
+    }
+    return *_fallbackComponentDescriptor.get();
   }
   return *it->second;
 }
@@ -123,5 +126,16 @@ SharedShadowNode ComponentDescriptorRegistry::createNode(
   return shadowNode;
 }
 
+void ComponentDescriptorRegistry::setFallbackComponentDescriptor(
+    SharedComponentDescriptor descriptor) {
+  _fallbackComponentDescriptor = descriptor;
+  registerComponentDescriptor(descriptor);
+}
+
+const SharedComponentDescriptor
+ComponentDescriptorRegistry::getFallbackComponentDescriptor() const {
+  return _fallbackComponentDescriptor;
+}
+
 } // namespace react
 } // namespace facebook

ReactCommon/fabric/uimanager/ComponentDescriptorRegistry.h

@@ -39,10 +39,13 @@ class ComponentDescriptorRegistry {
       Tag rootTag,
       const folly::dynamic &props,
       const SharedEventTarget &eventTarget) const;
+  void setFallbackComponentDescriptor(SharedComponentDescriptor descriptor);
+  const SharedComponentDescriptor getFallbackComponentDescriptor() const;
 
  private:
   better::map<ComponentHandle, SharedComponentDescriptor> _registryByHandle;
   better::map<ComponentName, SharedComponentDescriptor> _registryByName;
+  SharedComponentDescriptor _fallbackComponentDescriptor;
 };
 
 } // namespace react

ReactCommon/fabric/uimanager/UIManager.cpp

@@ -18,13 +18,22 @@ SharedShadowNode UIManager::createNode(
   SystraceSection s("UIManager::createNode");
 
   auto &componentDescriptor = componentDescriptorRegistry_->at(name);
+  auto fallbackDescriptor =
+      componentDescriptorRegistry_->getFallbackComponentDescriptor();
+
   const auto &props = componentDescriptor.cloneProps(nullptr, rawProps);
   const auto &state = componentDescriptor.createInitialState(props);
 
   auto shadowNode = componentDescriptor.createShadowNode({
       /* .tag = */ tag,
       /* .rootTag = */ surfaceId,
-      /* .props = */ props,
+      /* .props = */
+      fallbackDescriptor != nullptr &&
+              fallbackDescriptor->getComponentHandle() ==
+                  componentDescriptor.getComponentHandle()
+          ? componentDescriptor.cloneProps(
+                nullptr, RawProps(folly::dynamic::object("name", name)))
+          : props,
       /* .eventEmitter = */
       componentDescriptor.createEventEmitter(std::move(eventTarget), tag),
       /* .children = */ ShadowNodeFragment::childrenPlaceholder(),