Implement gating support for direction-aware API changes

Reviewed By: achen1

Differential Revision: D6045083

fbshipit-source-id: 857a43029ad88d2324ec77145a1e30d92b5e8fae

Libraries/ReactNative/I18nManager.js

@@ -14,14 +14,18 @@
 
 type I18nManagerStatus = {
   isRTL: boolean,
+  doesRTLFlipLeftAndRightStyles: boolean,
   allowRTL: (allowRTL: boolean) => {},
   forceRTL: (forceRTL: boolean) => {},
+  makeRTLFlipLeftAndRightStyles: (flipStyles: boolean) => {},
 };
 
 const I18nManager: I18nManagerStatus = require('NativeModules').I18nManager || {
   isRTL: false,
+  doesRTLFlipLeftAndRightStyles: true,
   allowRTL: () => {},
   forceRTL: () => {},
+  makeRTLFlipLeftAndRightStyles: () => {},
 };
 
 module.exports = I18nManager;

React/Modules/RCTI18nManager.m

@@ -29,10 +29,16 @@ RCT_EXPORT_METHOD(forceRTL:(BOOL)value)
   [[RCTI18nUtil sharedInstance] forceRTL:value];
 }
 
+RCT_EXPORT_METHOD(makeRTLFlipLeftAndRightStyles:(BOOL)value)
+{
+  [[RCTI18nUtil sharedInstance] makeRTLFlipLeftAndRightStyles:value];
+}
+
 - (NSDictionary *)constantsToExport
 {
   return @{
-    @"isRTL": @([[RCTI18nUtil sharedInstance] isRTL])
+    @"isRTL": @([[RCTI18nUtil sharedInstance] isRTL]),
+    @"doesRTLFlipLeftAndRightStyles": @([[RCTI18nUtil sharedInstance] doesRTLFlipLeftAndRightStyles])
   };
 }
 

React/Modules/RCTI18nUtil.h

@@ -24,5 +24,7 @@
 - (void)allowRTL:(BOOL)value;
 - (BOOL)isRTLForced;
 - (void)forceRTL:(BOOL)value;
+- (BOOL)doesRTLFlipLeftAndRightStyles;
+- (void)makeRTLFlipLeftAndRightStyles:(BOOL)value;
 
 @end

React/Modules/RCTI18nUtil.m

@@ -19,6 +19,7 @@
   static dispatch_once_t onceToken;
   dispatch_once(&onceToken, ^{
     sharedInstance = [self new];
+    [sharedInstance makeRTLFlipLeftAndRightStyles: true];
   });
   
   return sharedInstance;
@@ -78,6 +79,17 @@
   [[NSUserDefaults standardUserDefaults] synchronize];
 }
 
+- (BOOL)doesRTLFlipLeftAndRightStyles
+{
+  return [[NSUserDefaults standardUserDefaults] boolForKey:@"RCTI18nUtil_makeRTLFlipLeftAndRightStyles"];
+}
+
+- (void)makeRTLFlipLeftAndRightStyles:(BOOL)value
+{
+  [[NSUserDefaults standardUserDefaults] setBool:value forKey:@"RCTI18nUtil_makeRTLFlipLeftAndRightStyles"];
+  [[NSUserDefaults standardUserDefaults] synchronize];
+}
+
 // Check if the current device language is RTL
 - (BOOL)isDevicePreferredLanguageRTL
 {

ReactAndroid/src/main/java/com/facebook/react/modules/i18nmanager/I18nManagerModule.java

@@ -45,6 +45,7 @@ public class I18nManagerModule extends ContextBaseJavaModule {
 
     final Map<String, Object> constants = MapBuilder.newHashMap();
     constants.put("isRTL", sharedI18nUtilInstance.isRTL(context));
+    constants.put("doesRTLFlipLeftAndRightStyles", sharedI18nUtilInstance.doesRTLFlipLeftAndRightStyles(context));
     constants.put("localeIdentifier", locale.toString());
     return constants;
   }
@@ -58,4 +59,9 @@ public class I18nManagerModule extends ContextBaseJavaModule {
   public void forceRTL(boolean value) {
     sharedI18nUtilInstance.forceRTL(getContext(), value);
   }
+
+  @ReactMethod
+  public void makeRTLFlipLeftAndRightStyles(boolean value) {
+    sharedI18nUtilInstance.makeRTLFlipLeftAndRightStyles(getContext(), value);
+  }
 }

ReactAndroid/src/main/java/com/facebook/react/modules/i18nmanager/I18nUtil.java

@@ -26,6 +26,8 @@ public class I18nUtil {
     "RCTI18nUtil_allowRTL";
   private static final String KEY_FOR_PREFS_FORCERTL =
     "RCTI18nUtil_forceRTL";
+  private static final String KEY_FOR_PERFS_MAKE_RTL_FLIP_LEFT_AND_RIGHT_STYLES =
+    "RCTI18nUtil_makeRTLFlipLeftAndRightStyles";
 
   private I18nUtil() {
      // Exists only to defeat instantiation.
@@ -65,6 +67,14 @@ public class I18nUtil {
     setPref(context, KEY_FOR_PREFS_ALLOWRTL, allowRTL);
   }
 
+  public boolean doesRTLFlipLeftAndRightStyles(Context context) {
+    return isPrefSet(context, KEY_FOR_PERFS_MAKE_RTL_FLIP_LEFT_AND_RIGHT_STYLES, true);
+  }
+
+  public void makeRTLFlipLeftAndRightStyles(Context context, boolean flip) {
+    setPref(context, KEY_FOR_PERFS_MAKE_RTL_FLIP_LEFT_AND_RIGHT_STYLES, flip);
+  }
+
   /**
    * Could be used to test RTL layout with English
    * Used for development and testing purpose