Adds the ability to use UIManager to check if a node is an ancestor o…

…f other node. Added @alloy suggestions and refactored the descendant method name
facebook · Jun 21, 2016 · afb0f86 · afb0f86
1 parent 4c3c15f
commit afb0f86
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diff --git a/Examples/UIExplorer/UIExplorerUnitTests/RCTShadowViewTests.m b/Examples/UIExplorer/UIExplorerUnitTests/RCTShadowViewTests.m
@@ -106,6 +106,29 @@ - (void)testApplyingLayoutRecursivelyToShadowView
   XCTAssertTrue(CGRectEqualToRect([rightView measureLayoutRelativeToAncestor:self.parentView], CGRectMake(330, 120, 100, 200)));
 }
 
+- (void)testAncestorCheck
+{
+  RCTShadowView *centerView = [self _shadowViewWithStyle:^(css_style_t *style) {
+    style->flex = 1;
+  }];
+
+  RCTShadowView *mainView = [self _shadowViewWithStyle:^(css_style_t *style) {
+    style->flex = 1;
+  }];
+
+  [mainView insertReactSubview:centerView atIndex:0];
+
+  RCTShadowView *footerView = [self _shadowViewWithStyle:^(css_style_t *style) {
+    style->flex = 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:^(css_style_t *style) {

diff --git a/React/Modules/RCTUIManager.m b/React/Modules/RCTUIManager.m
@@ -1253,6 +1253,26 @@ - (void)setNeedsLayout
   }];
 }
 
+/**
+ * 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
@@ -213,4 +213,9 @@ 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
@@ -275,6 +275,17 @@ - (CGRect)measureLayoutRelativeToAncestor:(RCTShadowView *)ancestor
   return (CGRect){offset, self.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])) {