Layout marker metadata

Summary:
@public

Adds marker meta data to `YGMarkerLayout`: the number of measures, and the numbers of layouts for all nodes in the tree.

Reviewed By: SidharthGuglani

Differential Revision: D13838975

fbshipit-source-id: d575c26a3d5a4f0b66834eb6bedecadc3f3ca265

tests/InstrumentationTest.cpp

@@ -32,6 +32,9 @@ struct MarkerTest : public ::testing::Test {
   struct EndData {
     Data data;
     void* cookie;
+    union {
+      YGMarkerLayoutData layout;
+    } markerData;
   };
 
   static struct {
@@ -43,6 +46,7 @@ struct MarkerTest : public ::testing::Test {
   static void endMarker(YGMarker, YGNodeRef, YGMarkerData, void*);
   static uniquePtr<YGConfig> makeConfig();
   static uniquePtr<YGNode> makeNode(uniquePtr<YGConfig>&);
+  static uniquePtr<YGNode> makeNode(uniquePtr<YGConfig>&, uniquePtr<YGNode>&);
 
   void SetUp() override;
 };
@@ -95,6 +99,28 @@ TEST_F(MarkerTest, layout_marker) {
   ASSERT_EQ(markerCookie.start.node, root.get());
 }
 
+TEST_F(MarkerTest, layout_marker_counts_single_node_layout) {
+  auto config = makeConfig();
+  auto root = makeNode(config);
+
+  YGNodeCalculateLayout(root.get(), YGUndefined, YGUndefined, YGDirectionLTR);
+
+  ASSERT_EQ(markerCookie.end.markerData.layout.layouts, 1);
+  ASSERT_EQ(markerCookie.end.markerData.layout.measures, 0);
+}
+
+TEST_F(MarkerTest, layout_marker_counts_multi_node_layout) {
+  auto config = makeConfig();
+  auto root = makeNode(config);
+  auto childA = makeNode(config, root);
+  auto childB = makeNode(config, root);
+
+  YGNodeCalculateLayout(root.get(), YGUndefined, YGUndefined, YGDirectionLTR);
+
+  ASSERT_EQ(markerCookie.end.markerData.layout.layouts, 3);
+  ASSERT_EQ(markerCookie.end.markerData.layout.measures, 4);
+}
+
 void* MarkerTest::startMarker(
     YGMarker marker,
     YGNodeRef node,
@@ -108,7 +134,12 @@ void MarkerTest::endMarker(
     YGNodeRef node,
     YGMarkerData data,
     void* id) {
-  markerCookie.end = {{marker, node, data}, id};
+  markerCookie.end = {{marker, node, data}, id, {}};
+  switch (marker) {
+    case YGMarkerLayout:
+      markerCookie.end.markerData.layout = *marker::data<YGMarkerLayout>(data);
+      break;
+  };
 }
 
 uniquePtr<YGConfig> MarkerTest::makeConfig() {
@@ -122,6 +153,14 @@ uniquePtr<YGNode> MarkerTest::makeNode(uniquePtr<YGConfig>& config) {
   return n;
 }
 
+uniquePtr<YGNode> MarkerTest::makeNode(
+    uniquePtr<YGConfig>& config,
+    uniquePtr<YGNode>& owner) {
+  auto n = makeNode(config);
+  YGNodeInsertChild(owner.get(), n.get(), YGNodeGetChildCount(owner.get()));
+  return n;
+}
+
 void MarkerTest::SetUp() {
   markerCookie = {};
 }

yoga/YGMarker.h

@@ -18,7 +18,8 @@ typedef YG_ENUM_BEGIN(YGMarker){
 } YG_ENUM_END(YGMarker);
 
 typedef struct {
-  int unused;
+  int layouts;
+  int measures;
 } YGMarkerLayoutData;
 
 typedef union {
@@ -54,6 +55,15 @@ struct MarkerData<YGMarkerLayout> {
 };
 
 } // namespace detail
+
+template <YGMarker M>
+typename detail::MarkerData<M>::type* data(YGMarkerData) = delete;
+
+template <>
+inline YGMarkerLayoutData* data<YGMarkerLayout>(YGMarkerData d) {
+  return d.layout;
+}
+
 } // namespace marker
 } // namespace yoga
 } // namespace facebook

yoga/Yoga.cpp

@@ -2685,6 +2685,8 @@ static void YGNodelayoutImpl(
       "availableHeight is indefinite so heightMeasureMode must be "
       "YGMeasureModeUndefined");
 
+  (performLayout ? layoutMarkerData.layouts : layoutMarkerData.measures) += 1;
+
   // Set the resolved resolution in the node's layout.
   const YGDirection direction = node->resolveDirection(ownerDirection);
   node->setLayoutDirection(direction);