From 458c06b8e77c2e579d0986ec16b73a3c4fdceda7 Mon Sep 17 00:00:00 2001
From: David Vacca <dvacca@fb.com>
Date: Wed, 10 Jul 2019 20:52:57 -0700
Subject: [PATCH] Back out "[RN][iOS] Remove definition of viewIsDescendantOf
 method in RN iOS code"

Summary:
Adding viewIsDescendantOf back again, more context https://github.com/facebook/react-native/commit/9ae7f0c7dac732c8c2f2253699f7bcf04943e98b
This method might no not be implemented in Fabric

Reviewed By: fkgozali

Differential Revision: D16186406

fbshipit-source-id: 9cd4c9e20c01713d4e8608a54c6f54082067e27f
---
 .../RNTesterUnitTests/RCTShadowViewTests.m    | 23 +++++++++++++++++++
 React/Modules/RCTUIManager.m                  | 20 ++++++++++++++++
 React/Views/RCTShadowView.h                   |  5 ++++
 React/Views/RCTShadowView.m                   | 11 +++++++++
 4 files changed, 59 insertions(+)

diff --git a/RNTester/RNTesterUnitTests/RCTShadowViewTests.m b/RNTester/RNTesterUnitTests/RCTShadowViewTests.m
index d5cb09c89c1..eecd901f582 100644
--- a/RNTester/RNTesterUnitTests/RCTShadowViewTests.m
+++ b/RNTester/RNTesterUnitTests/RCTShadowViewTests.m
@@ -100,6 +100,29 @@
   XCTAssertTrue(CGRectEqualToRect([rightView measureLayoutRelativeToAncestor:self.parentView], CGRectMake(330, 120, 100, 200)));
 }
 
+- (void)testAncestorCheck
+{
+  RCTShadowView *centerView = [self _shadowViewWithConfig:^(YGNodeRef node) {
+    YGNodeStyleSetFlex(node, 1);
+  }];
+
+  RCTShadowView *mainView = [self _shadowViewWithConfig:^(YGNodeRef node) {
+    YGNodeStyleSetFlex(node, 1);
+  }];
+
+  [mainView insertReactSubview:centerView atIndex:0];
+
+  RCTShadowView *footerView = [self _shadowViewWithConfig:^(YGNodeRef node) {
+    YGNodeStyleSetFlex(node, 1);
+  }];
+
+  [self.parentView insertReactSubview:mainView atIndex:0];
+  [self.parentView insertReactSubview:footerView atIndex:1];
+
+  XCTAssertTrue([centerView viewIsDescendantOf:mainView]);
+  XCTAssertFalse([footerView viewIsDescendantOf:mainView]);
+}
+
 - (void)testAssignsSuggestedWidthDimension
 {
   [self _withShadowViewWithStyle:^(YGNodeRef node) {
diff --git a/React/Modules/RCTUIManager.m b/React/Modules/RCTUIManager.m
index 54c6b5cbd7d..1d7ac52a941 100644
--- a/React/Modules/RCTUIManager.m
+++ b/React/Modules/RCTUIManager.m
@@ -1321,6 +1321,26 @@ RCT_EXPORT_METHOD(measureInWindow:(nonnull NSNumber *)reactTag
   }];
 }
 
+/**
+ * Returs if the shadow view provided has the `ancestor` shadow view as
+ * an actual ancestor.
+ */
+RCT_EXPORT_METHOD(viewIsDescendantOf:(nonnull NSNumber *)reactTag
+                  ancestor:(nonnull NSNumber *)ancestorReactTag
+                  callback:(RCTResponseSenderBlock)callback)
+{
+  RCTShadowView *shadowView = _shadowViewRegistry[reactTag];
+  RCTShadowView *ancestorShadowView = _shadowViewRegistry[ancestorReactTag];
+  if (!shadowView) {
+    return;
+  }
+  if (!ancestorShadowView) {
+    return;
+  }
+  BOOL viewIsAncestor = [shadowView viewIsDescendantOf:ancestorShadowView];
+  callback(@[@(viewIsAncestor)]);
+}
+
 static void RCTMeasureLayout(RCTShadowView *view,
                              RCTShadowView *ancestor,
                              RCTResponseSenderBlock callback)
diff --git a/React/Views/RCTShadowView.h b/React/Views/RCTShadowView.h
index 326b8bc90e9..8d9828cb98a 100644
--- a/React/Views/RCTShadowView.h
+++ b/React/Views/RCTShadowView.h
@@ -235,4 +235,9 @@ typedef void (^RCTApplierBlock)(NSDictionary<NSNumber *, UIView *> *viewRegistry
  */
 - (CGRect)measureLayoutRelativeToAncestor:(RCTShadowView *)ancestor;
 
+/**
+ * Checks if the current shadow view is a descendant of the provided `ancestor`
+ */
+- (BOOL)viewIsDescendantOf:(RCTShadowView *)ancestor;
+
 @end
diff --git a/React/Views/RCTShadowView.m b/React/Views/RCTShadowView.m
index ecac8071eef..40c0cdaf8d8 100644
--- a/React/Views/RCTShadowView.m
+++ b/React/Views/RCTShadowView.m
@@ -170,6 +170,17 @@ static void RCTProcessMetaPropsBorder(const YGValue metaProps[META_PROP_COUNT],
   return (CGRect){offset, self.layoutMetrics.frame.size};
 }
 
+- (BOOL)viewIsDescendantOf:(RCTShadowView *)ancestor
+{
+  NSInteger depth = 30; // max depth to search
+  RCTShadowView *shadowView = self;
+  while (depth && shadowView && shadowView != ancestor) {
+    shadowView = shadowView->_superview;
+    depth--;
+  }
+  return ancestor == shadowView;
+}
+
 - (instancetype)init
 {
   if (self = [super init]) {