Data types for marker API

Summary:
@public

Adds types for a marker API in Yoga.

This will allow us to register callbacks that Yoga can use to log performance data without hard-coding the backend system for that.

Reviewed By: SidharthGuglani

Differential Revision: D13118830

fbshipit-source-id: b42a42c609f0cf66212186f7f20ee572522d59e3

yoga/YGConfig.h

@@ -6,6 +6,7 @@
  *
  */
 #pragma once
+#include "YGMarker.h"
 #include "Yoga-internal.h"
 #include "Yoga.h"
 
@@ -14,11 +15,12 @@ struct YGConfig {
   bool useWebDefaults = false;
   bool useLegacyStretchBehaviour = false;
   bool shouldDiffLayoutWithoutLegacyStretchBehaviour = false;
+  bool printTree = false;
   float pointScaleFactor = 1.0f;
   YGLogger logger;
   YGCloneNodeFunc cloneNodeCallback = nullptr;
   void* context = nullptr;
-  bool printTree = false;
+  YGMarkerCallbacks markerCallbacks = {nullptr, nullptr};
 
   YGConfig(YGLogger logger);
 };

yoga/YGMarker.h

@@ -0,0 +1,32 @@
+/**
+ * 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.
+ */
+
+#pragma once
+
+#include "YGMacros.h"
+
+YG_EXTERN_C_BEGIN
+
+typedef struct YGNode* YGNodeRef;
+
+typedef YG_ENUM_BEGIN(YGMarkerType) {}
+YG_ENUM_END(YGMarkerType);
+
+typedef union {
+  int unused;
+} YGMarkerData;
+
+typedef struct {
+  // accepts marker type, a node ref, and marker data (depends on marker type)
+  // can return a handle or id that Yoga will pass to endMarker
+  void* (*startMarker)(YGMarkerType, YGNodeRef, YGMarkerData);
+  // accepts marker type, a node ref, marker data, and marker id as returned
+  // by startMarker
+  void (*endMarker)(YGMarkerType, YGNodeRef, YGMarkerData, void* id);
+} YGMarkerCallbacks;
+
+YG_EXTERN_C_END