Add YGErrata Enum (#1256)

Summary:
Pull Request resolved: https://github.com/facebook/yoga/pull/1256

X-link: https://github.com/facebook/react-native/pull/37076

This adds a `YGErrata` bitset enum matching the API and guarantees described in https://github.com/facebook/yoga/issues/1247.

It is hooked up in later diffs. There are a couple of `YGExperimentalFeature` values that belong here, but keeping the current options means that the default `YGErrataNone` corresponds to existing default behavior, letting us stage the series of changes as:
1. Implement errata API
2. Update internal Yoga users we want to de-risk to `YGErrataClassic` or `YGErrataAll` (if setting `UseLegacyStretchBehaviour`)
3. Add new errata, changing Yoga defaults to be conformant, while letting internal apps opt into compatibility modes pending experimentation.

I also added a macro to let C++ users of Yoga perform bitwise operations on the enum without casting (already available for C users).

Reviewed By: rshest

Differential Revision: D45254098

fbshipit-source-id: d4b61271a8018f548f2d9d8c953db4b121a502d1

csharp/Facebook.Yoga/YogaErrata.cs

@@ -0,0 +1,20 @@
+/*
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+// @generated by enums.py
+
+namespace Facebook.Yoga
+{
+    [System.Flags]
+    public enum YogaErrata
+    {
+        None = 0,
+        StretchFlexBasis = 1,
+        All = 2147483647,
+        Classic = 2147483646,
+    }
+}

enums.py

@@ -59,6 +59,19 @@ ENUMS = {
     ],
     "PrintOptions": [("Layout", 1), ("Style", 2), ("Children", 4)],
     "Gutter": ["Column", "Row", "All"],
+    # Known incorrect behavior which can be enabled for compatibility
+    "Errata": [
+        # Default: Standards conformant mode
+        ("None", 0),
+        # Allows main-axis flex basis to be stretched without flexGrow being
+        # set (previously referred to as "UseLegacyStretchBehaviour")
+        ("StretchFlexBasis", 1 << 0),
+        # Enable all incorrect behavior (preserve compatibility)
+        ("All", 0x7FFFFFFF),
+        # Enable all errata except for "StretchFlexBasis" (Defaults behavior
+        # before Yoga 2.0)
+        ("Classic", 0x7FFFFFFF & (~(1 << 0))),
+    ],
 }
 
 # Generated Java enums used to emit @DoNotStrip, but D17519844 removed them
@@ -66,6 +79,8 @@ ENUMS = {
 # well?
 DO_NOT_STRIP = ["LogLevel"]
 
+BITSET_ENUMS = ["Errata"]
+
 
 def get_license(ext):
     prologue = "/**" if ext == "js" else "/*"
@@ -132,6 +147,8 @@ with open(root + "/yoga/YGEnums.h", "w") as f:
                 f.write(")\n")
             else:
                 f.write(",\n")
+        if name in BITSET_ENUMS:
+            f.write("YG_DEFINE_ENUM_FLAG_OPERATORS(YG%s)\n" % name)
         f.write("\n")
     f.write("YG_EXTERN_C_END\n")
 

java/com/facebook/yoga/YogaErrata.java

@@ -0,0 +1,37 @@
+/*
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+// @generated by enums.py
+
+package com.facebook.yoga;
+
+public enum YogaErrata {
+  NONE(0),
+  STRETCH_FLEX_BASIS(1),
+  ALL(2147483647),
+  CLASSIC(2147483646);
+
+  private final int mIntValue;
+
+  YogaErrata(int intValue) {
+    mIntValue = intValue;
+  }
+
+  public int intValue() {
+    return mIntValue;
+  }
+
+  public static YogaErrata fromInt(int value) {
+    switch (value) {
+      case 0: return NONE;
+      case 1: return STRETCH_FLEX_BASIS;
+      case 2147483647: return ALL;
+      case 2147483646: return CLASSIC;
+      default: throw new IllegalArgumentException("Unknown enum value: " + value);
+    }
+  }
+}

javascript/src_js/generated/YGEnums.d.ts

@@ -84,6 +84,19 @@ type EDGE_ALL = 8 & ['EDGE']
 export const EDGE_ALL: EDGE_ALL;
 
 
+type ERRATA_NONE = 0 & ['ERRATA']
+export const ERRATA_NONE: ERRATA_NONE;
+
+type ERRATA_STRETCH_FLEX_BASIS = 1 & ['ERRATA']
+export const ERRATA_STRETCH_FLEX_BASIS: ERRATA_STRETCH_FLEX_BASIS;
+
+type ERRATA_ALL = 2147483647 & ['ERRATA']
+export const ERRATA_ALL: ERRATA_ALL;
+
+type ERRATA_CLASSIC = 2147483646 & ['ERRATA']
+export const ERRATA_CLASSIC: ERRATA_CLASSIC;
+
+
 type EXPERIMENTAL_FEATURE_WEB_FLEX_BASIS = 0 & ['EXPERIMENTAL_FEATURE']
 export const EXPERIMENTAL_FEATURE_WEB_FLEX_BASIS: EXPERIMENTAL_FEATURE_WEB_FLEX_BASIS;
 
@@ -259,6 +272,12 @@ export type Edge =
   | typeof EDGE_VERTICAL
   | typeof EDGE_ALL;
 
+export type Errata =
+  | typeof ERRATA_NONE
+  | typeof ERRATA_STRETCH_FLEX_BASIS
+  | typeof ERRATA_ALL
+  | typeof ERRATA_CLASSIC;
+
 export type ExperimentalFeature =
   | typeof EXPERIMENTAL_FEATURE_WEB_FLEX_BASIS
   | typeof EXPERIMENTAL_FEATURE_ABSOLUTE_PERCENTAGE_AGAINST_PADDING_EDGE

javascript/src_js/generated/YGEnums.js

@@ -36,6 +36,11 @@ exports.EDGE_HORIZONTAL = 6;
 exports.EDGE_VERTICAL = 7;
 exports.EDGE_ALL = 8;
 
+exports.ERRATA_NONE = 0;
+exports.ERRATA_STRETCH_FLEX_BASIS = 1;
+exports.ERRATA_ALL = 2147483647;
+exports.ERRATA_CLASSIC = 2147483646;
+
 exports.EXPERIMENTAL_FEATURE_WEB_FLEX_BASIS = 0;
 exports.EXPERIMENTAL_FEATURE_ABSOLUTE_PERCENTAGE_AGAINST_PADDING_EDGE = 1;
 exports.EXPERIMENTAL_FEATURE_FIX_ABSOLUTE_TRAILING_COLUMN_MARGIN = 2;

yoga/YGEnums.cpp

@@ -87,6 +87,20 @@ const char* YGEdgeToString(const YGEdge value) {
   return "unknown";
 }
 
+const char* YGErrataToString(const YGErrata value) {
+  switch (value) {
+    case YGErrataNone:
+      return "none";
+    case YGErrataStretchFlexBasis:
+      return "stretch-flex-basis";
+    case YGErrataAll:
+      return "all";
+    case YGErrataClassic:
+      return "classic";
+  }
+  return "unknown";
+}
+
 const char* YGExperimentalFeatureToString(const YGExperimentalFeature value) {
   switch (value) {
     case YGExperimentalFeatureWebFlexBasis:

yoga/YGEnums.h

@@ -54,6 +54,14 @@ YG_ENUM_SEQ_DECL(
     YGEdgeVertical,
     YGEdgeAll)
 
+YG_ENUM_DECL(
+    YGErrata,
+    YGErrataNone = 0,
+    YGErrataStretchFlexBasis = 1,
+    YGErrataAll = 2147483647,
+    YGErrataClassic = 2147483646)
+YG_DEFINE_ENUM_FLAG_OPERATORS(YGErrata)
+
 YG_ENUM_SEQ_DECL(
     YGExperimentalFeature,
     YGExperimentalFeatureWebFlexBasis,

yoga/YGMacros.h

@@ -7,6 +7,10 @@
 
 #pragma once
 
+#ifdef __cplusplus
+#include <type_traits>
+#endif
+
 #ifdef __cplusplus
 #define YG_EXTERN_C_BEGIN extern "C" {
 #define YG_EXTERN_C_END }
@@ -40,6 +44,48 @@
 #define YG_ENUM_END(name) name
 #endif
 
+#ifdef __cplusplus
+#define YG_DEFINE_ENUM_FLAG_OPERATORS(name)                       \
+  extern "C++" {                                                  \
+  constexpr inline name operator~(name a) {                       \
+    return static_cast<name>(                                     \
+        ~static_cast<std::underlying_type<name>::type>(a));       \
+  }                                                               \
+  constexpr inline name operator|(name a, name b) {               \
+    return static_cast<name>(                                     \
+        static_cast<std::underlying_type<name>::type>(a) |        \
+        static_cast<std::underlying_type<name>::type>(b));        \
+  }                                                               \
+  constexpr inline name operator&(name a, name b) {               \
+    return static_cast<name>(                                     \
+        static_cast<std::underlying_type<name>::type>(a) &        \
+        static_cast<std::underlying_type<name>::type>(b));        \
+  }                                                               \
+  constexpr inline name operator^(name a, name b) {               \
+    return static_cast<name>(                                     \
+        static_cast<std::underlying_type<name>::type>(a) ^        \
+        static_cast<std::underlying_type<name>::type>(b));        \
+  }                                                               \
+  inline name& operator|=(name& a, name b) {                      \
+    return reinterpret_cast<name&>(                               \
+        reinterpret_cast<std::underlying_type<name>::type&>(a) |= \
+        static_cast<std::underlying_type<name>::type>(b));        \
+  }                                                               \
+  inline name& operator&=(name& a, name b) {                      \
+    return reinterpret_cast<name&>(                               \
+        reinterpret_cast<std::underlying_type<name>::type&>(a) &= \
+        static_cast<std::underlying_type<name>::type>(b));        \
+  }                                                               \
+  inline name& operator^=(name& a, name b) {                      \
+    return reinterpret_cast<name&>(                               \
+        reinterpret_cast<std::underlying_type<name>::type&>(a) ^= \
+        static_cast<std::underlying_type<name>::type>(b));        \
+  }                                                               \
+  }
+#else
+#define YG_DEFINE_ENUM_FLAG_OPERATORS(name)
+#endif
+
 #ifdef __cplusplus
 namespace facebook {
 namespace yoga {