From 5824dbda66b2e0f384afb544e4ad051a6b201c6f Mon Sep 17 00:00:00 2001
From: David Aurelio <davidaurelio@fb.com>
Date: Thu, 9 May 2019 04:14:08 -0700
Subject: [PATCH] Publish event when visiting nodes during layout

Summary:
@public

Publish an event when visiting nodes during layouts.

Reviewed By: SidharthGuglani

Differential Revision: D15206965

fbshipit-source-id: c201f084b1d4186bc64560b8033be965f2549236
---
 tests/EventsTest.cpp | 59 ++++++++++++++++++++++++++++++++------------
 yoga/Yoga.cpp        |  3 +++
 yoga/events.h        |  2 +-
 3 files changed, 47 insertions(+), 17 deletions(-)

diff --git a/tests/EventsTest.cpp b/tests/EventsTest.cpp
index 99adf8e8..09a67d27 100644
--- a/tests/EventsTest.cpp
+++ b/tests/EventsTest.cpp
@@ -10,8 +10,10 @@
 #include <yoga/YGNode.h>
 #include <yoga/testutil/testutil.h>
 
+#include <algorithm>
 #include <functional>
 #include <memory>
+#include <vector>
 
 namespace facebook {
 namespace yoga {
@@ -33,16 +35,18 @@ class EventTest : public ::testing::Test {
   static void listen(const YGNode&, Event::Type, Event::Data);
 
 public:
-  static EventArgs lastEvent;
+  static std::vector<EventArgs> events;
+  static EventArgs& lastEvent() { return events.back(); }
+  void TearDown() override;
 };
 
 TEST_F(EventTest, new_node_has_event) {
   auto c = YGConfigGetDefault();
   auto n = YGNodeNew();
 
-  ASSERT_EQ(lastEvent.node, n);
-  ASSERT_EQ(lastEvent.type, Event::NodeAllocation);
-  ASSERT_EQ(lastEvent.data<Event::NodeAllocation>().config, c);
+  ASSERT_EQ(lastEvent().node, n);
+  ASSERT_EQ(lastEvent().type, Event::NodeAllocation);
+  ASSERT_EQ(lastEvent().data<Event::NodeAllocation>().config, c);
 
   YGNodeFree(n);
 }
@@ -51,9 +55,9 @@ TEST_F(EventTest, new_node_with_config_event) {
   auto c = YGConfigNew();
   auto n = YGNodeNewWithConfig(c);
 
-  ASSERT_EQ(lastEvent.node, n);
-  ASSERT_EQ(lastEvent.type, Event::NodeAllocation);
-  ASSERT_EQ(lastEvent.data<Event::NodeAllocation>().config, c);
+  ASSERT_EQ(lastEvent().node, n);
+  ASSERT_EQ(lastEvent().type, Event::NodeAllocation);
+  ASSERT_EQ(lastEvent().data<Event::NodeAllocation>().config, c);
 
   YGNodeFree(n);
   YGConfigFree(c);
@@ -64,9 +68,9 @@ TEST_F(EventTest, clone_node_event) {
   auto n = YGNodeNewWithConfig(c);
   auto clone = YGNodeClone(n);
 
-  ASSERT_EQ(lastEvent.node, clone);
-  ASSERT_EQ(lastEvent.type, Event::NodeAllocation);
-  ASSERT_EQ(lastEvent.data<Event::NodeAllocation>().config, c);
+  ASSERT_EQ(lastEvent().node, clone);
+  ASSERT_EQ(lastEvent().type, Event::NodeAllocation);
+  ASSERT_EQ(lastEvent().data<Event::NodeAllocation>().config, c);
 
   YGNodeFree(n);
   YGNodeFree(clone);
@@ -78,13 +82,29 @@ TEST_F(EventTest, free_node_event) {
   auto n = YGNodeNewWithConfig(c);
   YGNodeFree(n);
 
-  ASSERT_EQ(lastEvent.node, n);
-  ASSERT_EQ(lastEvent.type, Event::NodeDeallocation);
-  ASSERT_EQ(lastEvent.data<Event::NodeDeallocation>().config, c);
+  ASSERT_EQ(lastEvent().node, n);
+  ASSERT_EQ(lastEvent().type, Event::NodeDeallocation);
+  ASSERT_EQ(lastEvent().data<Event::NodeDeallocation>().config, c);
 
   YGConfigFree(c);
 }
 
+TEST_F(EventTest, layout_events) {
+  auto root = YGNodeNew();
+  auto child = YGNodeNew();
+  YGNodeInsertChild(root, child, 0);
+
+  YGNodeCalculateLayout(root, 123, 456, YGDirectionLTR);
+
+  ASSERT_EQ(events[2].node, root);
+  ASSERT_EQ(events[2].type, Event::NodeLayout);
+
+  ASSERT_EQ(events[3].node, child);
+  ASSERT_EQ(events[3].type, Event::NodeLayout);
+
+  YGNodeFreeRecursive(root);
+}
+
 namespace {
 
 template <Event::Type E>
@@ -99,15 +119,22 @@ EventArgs createArgs(const YGNode& node, const Event::Data& data) {
 void EventTest::listen(const YGNode& node, Event::Type type, Event::Data data) {
   switch (type) {
     case Event::NodeAllocation:
-      lastEvent = createArgs<Event::NodeAllocation>(node, data);
+      events.push_back(createArgs<Event::NodeAllocation>(node, data));
       break;
     case Event::NodeDeallocation:
-      lastEvent = createArgs<Event::NodeDeallocation>(node, data);
+      events.push_back(createArgs<Event::NodeDeallocation>(node, data));
+      break;
+    case Event::NodeLayout:
+      events.push_back(createArgs<Event::NodeLayout>(node, data));
       break;
   }
 }
 
-EventArgs EventTest::lastEvent{};
+void EventTest::TearDown() {
+  events.clear();
+}
+
+std::vector<EventArgs> EventTest::events{};
 
 } // namespace test
 } // namespace yoga
diff --git a/yoga/Yoga.cpp b/yoga/Yoga.cpp
index 05fb10d2..5f6fa875 100644
--- a/yoga/Yoga.cpp
+++ b/yoga/Yoga.cpp
@@ -3667,6 +3667,9 @@ bool YGLayoutNodeInternal(
     const YGConfigRef config,
     YGMarkerLayoutData& layoutMarkerData,
     void* const layoutContext) {
+#ifdef YG_ENABLE_EVENTS
+  Event::publish<Event::NodeLayout>(node);
+#endif
   YGLayout* layout = &node->getLayout();
 
   gDepth++;
diff --git a/yoga/events.h b/yoga/events.h
index 7b04060a..e667d2d2 100644
--- a/yoga/events.h
+++ b/yoga/events.h
@@ -15,7 +15,7 @@ namespace facebook {
 namespace yoga {
 
 struct Event {
-  enum Type { NodeAllocation, NodeDeallocation };
+  enum Type { NodeAllocation, NodeDeallocation, NodeLayout };
   class Data;
   using Subscriber = void(const YGNode&, Type, Data);