Introduce an abstraction for getting the effective font size

...which further de-duplicates the `Spannable`-building code

Author: cubuspl42

packages/react-native/ReactAndroid/src/main/java/com/facebook/react/views/text/EffectiveTextAttributeProvider.java

@@ -1,13 +1,21 @@
 package com.facebook.react.views.text;
 
+import com.facebook.react.common.assets.ReactFontManager;
 import com.facebook.react.uimanager.ReactAccessibilityDelegate;
 import com.facebook.react.uimanager.ReactAccessibilityDelegate.Role;
 
 public interface EffectiveTextAttributeProvider {
+  int UNSET = ReactFontManager.TypefaceStyle.UNSET;
+
   TextTransform getTextTransform();
 
   float getEffectiveLetterSpacing();
 
+  /**
+   * @return The effective font size, or {@link #UNSET} if not set
+   */
+  int getEffectiveFontSize();
+
   Role getRole();
 
   ReactAccessibilityDelegate.AccessibilityRole getAccessibilityRole();

packages/react-native/ReactAndroid/src/main/java/com/facebook/react/views/text/ReactBaseTextShadowNode.java

@@ -160,6 +160,20 @@ public float getEffectiveLetterSpacing() {
       }
     }
 
+    @Override
+    public int getEffectiveFontSize() {
+      final int fontSize = textAttributes.getEffectiveFontSize();
+
+      if (
+        // `getEffectiveFontSize` always returns a value so don't need to check for anything like `Float.NaN`.
+        parentTextAttributes == null
+          || parentTextAttributes.getEffectiveFontSize() != fontSize) {
+        return fontSize;
+      } else {
+        return UNSET;
+      }
+    }
+
     @Override
     public float getEffectiveLineHeight() {
       final float lineHeight = textAttributes.getEffectiveLineHeight();
@@ -276,13 +290,8 @@ private static void buildSpannedFromShadowNode(
 
       TextLayoutUtils.addLetterSpacingSpanIfApplicable(ops, textAttributeProvider, start, end);
 
-      int effectiveFontSize = textAttributes.getEffectiveFontSize();
-      if ( // `getEffectiveFontSize` always returns a value so don't need to check for anything like
-      // `Float.NaN`.
-      parentTextAttributes == null
-          || parentTextAttributes.getEffectiveFontSize() != effectiveFontSize) {
-        TextLayoutUtils.addFontSizeSpan(ops, start, end, effectiveFontSize);
-      }
+      TextLayoutUtils.addFontSizeSpanIfApplicable(ops, textAttributeProvider, start, end);
+
       TextLayoutUtils.addCustomStyleSpanIfApplicable(ops, textAttributeProvider, textShadowNode.getThemedContext(), start, end);
 
       TextLayoutUtils.addUnderlineSpanIfApplicable(ops, textAttributeProvider, start, end);

packages/react-native/ReactAndroid/src/main/java/com/facebook/react/views/text/TextAttributeProps.java

@@ -392,6 +392,11 @@ public float getEffectiveLetterSpacing() {
     return letterSpacingPixels / mFontSize;
   }
 
+  @Override
+  public int getEffectiveFontSize() {
+    return mFontSize;
+  }
+
   private void setAllowFontScaling(boolean allowFontScaling) {
     if (allowFontScaling != mAllowFontScaling) {
       mAllowFontScaling = allowFontScaling;

packages/react-native/ReactAndroid/src/main/java/com/facebook/react/views/text/TextLayoutUtils.java

@@ -51,7 +51,7 @@ public static void buildSpannableFromTextFragmentList(Context context, TextFragm
 
         addLetterSpacingSpanIfApplicable(ops, textAttributes, start, end);
 
-        addFontSizeSpan(ops, start, end, textAttributes.mFontSize);
+        addFontSizeSpanIfApplicable(ops, textAttributes, start, end);
 
         addCustomStyleSpanIfApplicable(ops, textAttributes, context, start, end);
 
@@ -119,9 +119,14 @@ public static void addLetterSpacingSpanIfApplicable(List<SetSpanOperation> ops,
   }
 
 
-  public static void addFontSizeSpan(List<SetSpanOperation> ops, int start, int end, int effectiveFontSize) {
+  public static void addFontSizeSpanIfApplicable(List<SetSpanOperation> ops,
+                                                 EffectiveTextAttributeProvider textAttributeProvider, int start,
+                                                 int end) {
+    final int effectiveFontSize = textAttributeProvider.getEffectiveFontSize();
 
-    ops.add(new SetSpanOperation(start, end, new ReactAbsoluteSizeSpan(effectiveFontSize)));
+    if (effectiveFontSize != UNSET) {
+      ops.add(new SetSpanOperation(start, end, new ReactAbsoluteSizeSpan(effectiveFontSize)));
+    }
   }
 
   public static void addCustomStyleSpanIfApplicable(List<SetSpanOperation> ops,