From c97faa25605260e552e6ab405dd82eeb75c34a06 Mon Sep 17 00:00:00 2001
From: David Vacca <dvacca@fb.com>
Date: Mon, 17 Sep 2018 18:46:10 -0700
Subject: [PATCH] specialize std::hash for enum classes

Summary: This diff fixes the compilation error: "implicit instantiation of undefined template std::hash" when using TextAttributes in Android

Reviewed By: shergin

Differential Revision: D9849407

fbshipit-source-id: 7fcb94b1d4f7715d8037ecbf302d8f345e99e9fd
---
 .../fabric/attributedstring/primitives.h      | 89 +++++++++++++++++++
 .../fabric/core/layout/LayoutPrimitives.h     | 15 ++++
 .../fabric/graphics/platform/android/Color.h  | 13 +++
 3 files changed, 117 insertions(+)

diff --git a/ReactCommon/fabric/attributedstring/primitives.h b/ReactCommon/fabric/attributedstring/primitives.h
index 84d30e1566b..a59024e53a6 100644
--- a/ReactCommon/fabric/attributedstring/primitives.h
+++ b/ReactCommon/fabric/attributedstring/primitives.h
@@ -7,6 +7,10 @@
 
 #pragma once
 
+
+#include <functional>
+#include <limits>
+
 namespace facebook {
 namespace react {
 
@@ -81,6 +85,7 @@ enum class TextDecorationLineStyle {
   Double
 };
 
+
 enum class TextDecorationLinePattern {
   Solid,
   Dot,
@@ -89,6 +94,90 @@ enum class TextDecorationLinePattern {
   DashDotDot,
 };
 
+
 } // namespace react
 } // namespace facebook
 
+namespace std
+{
+	template <>
+	struct hash<facebook::react::FontVariant>
+	{
+		size_t operator()(const facebook::react::FontVariant& v) const
+		{
+			return hash<int>()(static_cast<int>(v));
+		}
+	};
+
+	template <>
+	struct hash<facebook::react::TextAlignment>
+	{
+		size_t operator()(const facebook::react::TextAlignment& v) const
+		{
+			return hash<int>()(static_cast<int>(v));
+		}
+	};
+
+	template <>
+	struct hash<facebook::react::FontStyle>
+	{
+		size_t operator()(const facebook::react::FontStyle& v) const
+		{
+			return hash<int>()(static_cast<int>(v));
+		}
+	};
+
+	template <>
+	struct hash<facebook::react::TextDecorationLineType>
+	{
+		size_t operator()(const facebook::react::TextDecorationLineType& v) const
+		{
+			return hash<int>()(static_cast<int>(v));
+		}
+	};
+
+	template <>
+	struct hash<facebook::react::WritingDirection>
+	{
+		size_t operator()(const facebook::react::WritingDirection& v) const
+		{
+			return hash<int>()(static_cast<int>(v));
+		}
+	};
+
+	template <>
+	struct hash<facebook::react::TextDecorationLinePattern>
+	{
+		size_t operator()(const facebook::react::TextDecorationLinePattern& v) const
+		{
+			return hash<int>()(static_cast<int>(v));
+		}
+	};
+
+	template <>
+	struct hash<facebook::react::TextDecorationLineStyle>
+	{
+		size_t operator()(const facebook::react::TextDecorationLineStyle& v) const
+		{
+			return hash<int>()(static_cast<int>(v));
+		}
+	};
+
+	template <>
+	struct hash<facebook::react::FontWeight>
+	{
+		size_t operator()(const facebook::react::FontWeight& v) const
+		{
+			return hash<int>()(static_cast<int>(v));
+		}
+	};
+
+	template <>
+	struct hash<facebook::react::EllipsizeMode>
+	{
+		size_t operator()(const facebook::react::EllipsizeMode& v) const
+		{
+			return hash<int>()(static_cast<int>(v));
+		}
+	};
+}
diff --git a/ReactCommon/fabric/core/layout/LayoutPrimitives.h b/ReactCommon/fabric/core/layout/LayoutPrimitives.h
index bce2bc46fdf..fc74187e823 100644
--- a/ReactCommon/fabric/core/layout/LayoutPrimitives.h
+++ b/ReactCommon/fabric/core/layout/LayoutPrimitives.h
@@ -7,6 +7,9 @@
 
 #pragma once
 
+#include <functional>
+#include <limits>
+
 namespace facebook {
 namespace react {
 
@@ -31,3 +34,15 @@ enum class LayoutDirection {
 
 } // namespace react
 } // namespace facebook
+
+namespace std
+{
+	template <>
+	struct hash<facebook::react::LayoutDirection>
+	{
+		size_t operator()(const facebook::react::LayoutDirection& v) const
+		{
+			return hash<int>()(static_cast<int>(v));
+		}
+	};
+}
diff --git a/ReactCommon/fabric/graphics/platform/android/Color.h b/ReactCommon/fabric/graphics/platform/android/Color.h
index 69b13e76c78..3ae7d5cb8e8 100644
--- a/ReactCommon/fabric/graphics/platform/android/Color.h
+++ b/ReactCommon/fabric/graphics/platform/android/Color.h
@@ -7,6 +7,7 @@
 
 #pragma once
 
+#include <functional>
 #include <limits>
 
 #include <fabric/graphics/ColorComponents.h>
@@ -58,3 +59,15 @@ ColorComponents colorComponentsFromColor(SharedColor color);
 
 } // namespace react
 } // namespace facebook
+
+namespace std
+{
+	template <>
+	struct hash<facebook::react::SharedColor>
+	{
+		size_t operator()(const facebook::react::SharedColor& sharedColor) const
+		{
+			return hash<decltype(*sharedColor)>{}(*sharedColor);
+		}
+	};
+}