Fabric: New, much fancier, approach to parse dynamic props

Summary:
The new approach uses C++ overloading feature instead of specifying exact types in macros manually.
*Almost* macro-free!

Reviewed By: mdvacca

Differential Revision: D7738584

fbshipit-source-id: 85f8e4c1037b452df5e73b093dced9392cb2f73e

ReactCommon/fabric/core/shadownode/Props.cpp

@@ -7,6 +7,7 @@
 
 #include "Props.h"
 
+#include <fabric/core/propsConversions.h>
 #include <folly/dynamic.h>
 
 namespace facebook {
@@ -15,14 +16,7 @@ namespace react {
 void Props::apply(const RawProps &rawProps) {
   ensureUnsealed();
 
-  for (auto const &pair : rawProps) {
-    auto const &name = pair.first;
-    auto const &value = pair.second;
-
-    if (name == "nativeID") {
-      nativeId_ = value.asString();
-    }
-  }
+  applyRawProp(rawProps, "nativeID", nativeId_);
 }
 
 const std::string &Props::getNativeId() const {

ReactCommon/fabric/core/shadownode/propsConversions.h

@@ -0,0 +1,52 @@
+/**
+ * Copyright (c) 2015-present, Facebook, Inc.
+ *
+ * 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 <folly/dynamic.h>
+#include <fabric/graphics/Color.h>
+#include <fabric/graphics/Geometry.h>
+#include <fabric/graphics/graphicValuesConversions.h>
+
+namespace facebook {
+namespace react {
+
+inline bool boolFromDynamic(const folly::dynamic &value) { return value.getBool(); }
+inline int intFromDynamic(const folly::dynamic &value) { return value.getInt(); }
+inline Float floatFromDynamic(const folly::dynamic &value) { return value.getDouble(); }
+inline std::string stringFromDynamic(const folly::dynamic &value) { return value.getString(); }
+
+#define APPLY_RAW_PROP_TEMPLATE(type, converter) \
+inline static void applyRawProp(const RawProps &rawProps, const std::string &name, type &property) { \
+  auto &&iterator = rawProps.find(name); \
+  if (iterator != rawProps.end()) { \
+    property = converter(iterator->second); \
+  } \
+} \
+\
+inline static void applyRawProp(const RawProps &rawProps, const std::string &name, folly::Optional<type> &property) { \
+  auto &&iterator = rawProps.find(name); \
+  if (iterator != rawProps.end()) { \
+    auto &&value = iterator->second; \
+    if (value.isNull()) { \
+      property = {}; \
+    } else { \
+      property = converter(value); \
+    } \
+  } \
+}
+
+APPLY_RAW_PROP_TEMPLATE(bool, boolFromDynamic)
+APPLY_RAW_PROP_TEMPLATE(int, intFromDynamic)
+APPLY_RAW_PROP_TEMPLATE(Float, floatFromDynamic)
+APPLY_RAW_PROP_TEMPLATE(std::string, stringFromDynamic)
+APPLY_RAW_PROP_TEMPLATE(SharedColor, colorFromDynamic)
+APPLY_RAW_PROP_TEMPLATE(Point, pointFromDynamic)
+APPLY_RAW_PROP_TEMPLATE(Size, sizeFromDynamic)
+
+} // namespace react
+} // namespace facebook

ReactCommon/fabric/view/ViewProps.cpp

@@ -9,6 +9,7 @@
 
 #include <fabric/debug/DebugStringConvertibleItem.h>
 #include <fabric/graphics/graphicValuesConversions.h>
+#include <fabric/core/propsConversions.h>
 
 namespace facebook {
 namespace react {
@@ -17,32 +18,10 @@ void ViewProps::apply(const RawProps &rawProps) {
   Props::apply(rawProps);
   YogaStylableProps::apply(rawProps);
 
-  for (auto const &pair : rawProps) {
-    auto const &name = pair.first;
-    auto const &value = pair.second;
-
-    #pragma mark View Specific Properties
-
-    if (name == "zIndex") {
-      zIndex_ = value.asInt();
-      continue;
-    }
-
-    if (name == "opacity") {
-      opacity_ = value.asDouble();
-      continue;
-    }
-
-    if (name == "color") {
-      foregroundColor_ = colorFromDynamic(value);
-      continue;
-    }
-
-    if (name == "backgroundColor") {
-      backgroundColor_ = colorFromDynamic(value);
-      continue;
-    }
-  }
+  applyRawProp(rawProps, "zIndex", zIndex_);
+  applyRawProp(rawProps, "opacity", opacity_);
+  applyRawProp(rawProps, "color", foregroundColor_);
+  applyRawProp(rawProps, "backgroundColor", backgroundColor_);
 }
 
 #pragma mark - Getters

ReactCommon/fabric/view/ViewProps.h

@@ -33,19 +33,19 @@ public:
   SharedColor getForegroundColor() const;
   SharedColor getBackgroundColor() const;
 
+#pragma mark - DebugStringConvertible
+
+  SharedDebugStringConvertibleList getDebugProps() const override;
+
 private:
   int zIndex_ {0};
-  float opacity_ {1.0};
+  Float opacity_ {1.0};
 
   SharedColor foregroundColor_ {nullptr};
   SharedColor backgroundColor_ {nullptr};
 
   SharedColor shadowColor_ {nullptr};
   Point shadowOffset_ {0, 0};
-
-#pragma mark - DebugStringConvertible
-
-  SharedDebugStringConvertibleList getDebugProps() const override;
 };
 
 } // namespace react