Proper type for RCTBackedTextInputViewProtocol::defaultTextAttributes

Summary:
This diff changes how we apply default text attributes to backed text input.
The original change in https://github.com/facebook/react-native/pull/23585 that introduced the `reactTextAttributes` field in for RCTBackedTextInputViewProtocol was great! Thank you Wu zhongwuzw !
However, there is one detail that needs to be changed.
RCTBackedTextInputViewProtocol is designed to only abstract complexity of iOS text input components (UITextView and UITextField); it intentionally does not have any React-specific fields or types. Adding a field `RCTTextAttributes *reactTextAttributes;` violates this principle and make it hard to reuse this functionality in the new Fabric-powered TextInput.

This diff changes the type of this prop from `RCTTextAttributes` to `NSDictionary<NSAttributedStringKey,id> *`  (exact same type that UITextView and UITextField use).

Reviewed By: cpojer

Differential Revision: D17408501

fbshipit-source-id: 65f2bba119ccc30f22e87c28d0f8ea6f731cd365

Libraries/Text/TextInput/Multiline/RCTUITextView.m

@@ -18,10 +18,9 @@
   UILabel *_placeholderView;
   UITextView *_detachedTextView;
   RCTBackedTextViewDelegateAdapter *_textInputDelegateAdapter;
+  NSDictionary<NSAttributedStringKey, id> *_defaultTextAttributes;
 }
 
-@synthesize reactTextAttributes = _reactTextAttributes;
-
 static UIFont *defaultPlaceholderFont()
 {
   return [UIFont systemFontOfSize:17];
@@ -44,7 +43,6 @@ static UIColor *defaultPlaceholderColor()
     _placeholderView = [[UILabel alloc] initWithFrame:self.bounds];
     _placeholderView.isAccessibilityElement = NO;
     _placeholderView.numberOfLines = 0;
-    _placeholderView.textColor = defaultPlaceholderColor();
     [self addSubview:_placeholderView];
 
     _textInputDelegateAdapter = [[RCTBackedTextViewDelegateAdapter alloc] initWithTextView:self];
@@ -91,35 +89,31 @@ static UIColor *defaultPlaceholderColor()
 - (void)setPlaceholder:(NSString *)placeholder
 {
   _placeholder = placeholder;
-  _placeholderView.attributedText = [[NSAttributedString alloc] initWithString:_placeholder ?: @"" attributes:[self placeholderEffectiveTextAttributes]];
+  [self _updatePlaceholder];
 }
 
 - (void)setPlaceholderColor:(UIColor *)placeholderColor
 {
   _placeholderColor = placeholderColor;
-  _placeholderView.textColor = _placeholderColor ?: defaultPlaceholderColor();
+  [self _updatePlaceholder];
 }
 
-- (void)setReactTextAttributes:(RCTTextAttributes *)reactTextAttributes
+- (void)setDefaultTextAttributes:(NSDictionary<NSAttributedStringKey, id> *)defaultTextAttributes
 {
-  if ([reactTextAttributes isEqual:_reactTextAttributes]) {
-    return;
-  }
-  self.typingAttributes = reactTextAttributes.effectiveTextAttributes;
-  _reactTextAttributes = reactTextAttributes;
-  // Update placeholder text attributes
-  [self setPlaceholder:_placeholder];
+  _defaultTextAttributes = defaultTextAttributes;
+  self.typingAttributes = defaultTextAttributes;
+  [self _updatePlaceholder];
 }
 
-- (RCTTextAttributes *)reactTextAttributes
+- (NSDictionary<NSAttributedStringKey, id> *)defaultTextAttributes
 {
-  return _reactTextAttributes;
+  return _defaultTextAttributes;
 }
 
 - (void)textDidChange
 {
   _textWasPasted = NO;
-  [self invalidatePlaceholderVisibility];
+  [self _invalidatePlaceholderVisibility];
 }
 
 #pragma mark - Overrides
@@ -127,7 +121,7 @@ static UIColor *defaultPlaceholderColor()
 - (void)setFont:(UIFont *)font
 {
   [super setFont:font];
-  _placeholderView.font = font ?: defaultPlaceholderFont();
+  [self _updatePlaceholder];
 }
 
 - (void)setTextAlignment:(NSTextAlignment)textAlignment
@@ -195,7 +189,7 @@ static UIColor *defaultPlaceholderColor()
   UIEdgeInsets textContainerInset = self.textContainerInset;
   NSString *placeholder = self.placeholder ?: @"";
   CGSize maxPlaceholderSize = CGSizeMake(UIEdgeInsetsInsetRect(self.bounds, textContainerInset).size.width, CGFLOAT_MAX);
-  CGSize placeholderSize = [placeholder boundingRectWithSize:maxPlaceholderSize options:NSStringDrawingUsesLineFragmentOrigin attributes:[self placeholderEffectiveTextAttributes] context:nil].size;
+  CGSize placeholderSize = [placeholder boundingRectWithSize:maxPlaceholderSize options:NSStringDrawingUsesLineFragmentOrigin attributes:[self _placeholderTextAttributes] context:nil].size;
   placeholderSize = CGSizeMake(RCTCeilPixelValue(placeholderSize.width), RCTCeilPixelValue(placeholderSize.height));
   placeholderSize.width += textContainerInset.left + textContainerInset.right;
   placeholderSize.height += textContainerInset.top + textContainerInset.bottom;
@@ -253,25 +247,28 @@ static UIColor *defaultPlaceholderColor()
 
 #pragma mark - Placeholder
 
-- (void)invalidatePlaceholderVisibility
+- (void)_invalidatePlaceholderVisibility
 {
   BOOL isVisible = _placeholder.length != 0 && self.attributedText.length == 0;
   _placeholderView.hidden = !isVisible;
 }
 
-- (NSDictionary<NSAttributedStringKey, id> *)placeholderEffectiveTextAttributes
+- (void)_updatePlaceholder
 {
-  NSMutableDictionary<NSAttributedStringKey, id> *effectiveTextAttributes = [NSMutableDictionary dictionaryWithDictionary:@{
-                                                                                                                            NSFontAttributeName: _reactTextAttributes.effectiveFont ?: defaultPlaceholderFont(),
-                                                                                                                            NSForegroundColorAttributeName: self.placeholderColor ?: defaultPlaceholderColor(),
-                                                                                                                            NSKernAttributeName:isnan(_reactTextAttributes.letterSpacing) ? @0 : @(_reactTextAttributes.letterSpacing)
-                                                                                                                            }];
-  NSParagraphStyle *paragraphStyle = [_reactTextAttributes effectiveParagraphStyle];
-  if (paragraphStyle) {
-    effectiveTextAttributes[NSParagraphStyleAttributeName] = paragraphStyle;
+  _placeholderView.attributedText = [[NSAttributedString alloc] initWithString:_placeholder ?: @"" attributes:[self _placeholderTextAttributes]];
+}
+
+- (NSDictionary<NSAttributedStringKey, id> *)_placeholderTextAttributes
+{
+  NSMutableDictionary<NSAttributedStringKey, id> *textAttributes = [_defaultTextAttributes mutableCopy] ?: [NSMutableDictionary new];
+
+  [textAttributes setValue:self.placeholderColor ?: defaultPlaceholderColor() forKey:NSForegroundColorAttributeName];
+
+  if (![textAttributes objectForKey:NSFontAttributeName]) {
+    [textAttributes setValue:defaultPlaceholderFont() forKey:NSFontAttributeName];
   }
-  
-  return [effectiveTextAttributes copy];
+
+  return textAttributes;
 }
 
 #pragma mark - Utility Methods

Libraries/Text/TextInput/RCTBackedTextInputViewProtocol.h

@@ -25,7 +25,7 @@ NS_ASSUME_NONNULL_BEGIN
 @property (nonatomic, strong, nullable) UIView *inputAccessoryView;
 @property (nonatomic, weak, nullable) id<RCTBackedTextInputDelegate> textInputDelegate;
 @property (nonatomic, readonly) CGSize contentSize;
-@property (nonatomic, strong, nullable) RCTTextAttributes *reactTextAttributes;
+@property (nonatomic, strong, nullable) NSDictionary<NSAttributedStringKey,id> *defaultTextAttributes;
 
 // This protocol disallows direct access to `selectedTextRange` property because
 // unwise usage of it can break the `delegate` behavior. So, we always have to

Libraries/Text/TextInput/RCTBaseTextInputShadowView.m

@@ -47,6 +47,16 @@
   return YES;
 }
 
+- (void)didSetProps:(NSArray<NSString *> *)changedProps
+{
+  [super didSetProps:changedProps];
+
+  // `backgroundColor` and `opacity` are being applied directly to a UIView,
+  // therefore we need to exclude them from base `textAttributes`.
+  self.textAttributes.backgroundColor = nil;
+  self.textAttributes.opacity = NAN;
+}
+
 - (void)layoutSubviewsWithContext:(RCTLayoutContext)layoutContext
 {
   // Do nothing.

Libraries/Text/TextInput/RCTBaseTextInputView.m

@@ -67,7 +67,7 @@ RCT_NOT_IMPLEMENTED(- (instancetype)initWithFrame:(CGRect)frame)
 - (void)enforceTextAttributesIfNeeded
 {
   id<RCTBackedTextInputViewProtocol> backedTextInputView = self.backedTextInputView;
-  backedTextInputView.reactTextAttributes = _textAttributes;
+  backedTextInputView.defaultTextAttributes = [_textAttributes effectiveTextAttributes];
 }
 
 - (void)setReactPaddingInsets:(UIEdgeInsets)reactPaddingInsets

Libraries/Text/TextInput/Singleline/RCTUITextField.m

@@ -15,10 +15,9 @@
 
 @implementation RCTUITextField {
   RCTBackedTextFieldDelegateAdapter *_textInputDelegateAdapter;
+  NSDictionary<NSAttributedStringKey, id> *_defaultTextAttributes;
 }
 
-@synthesize reactTextAttributes = _reactTextAttributes;
-
 - (instancetype)initWithFrame:(CGRect)frame
 {
   if (self = [super initWithFrame:frame]) {
@@ -72,29 +71,22 @@
   [self _updatePlaceholder];
 }
 
-- (void)setReactTextAttributes:(RCTTextAttributes *)reactTextAttributes
+- (void)setDefaultTextAttributes:(NSDictionary<NSAttributedStringKey, id> *)defaultTextAttributes
 {
-  if ([reactTextAttributes isEqual:_reactTextAttributes]) {
-    return;
-  }
-  self.defaultTextAttributes = reactTextAttributes.effectiveTextAttributes;
-  _reactTextAttributes = reactTextAttributes;
+  _defaultTextAttributes = defaultTextAttributes;
+  [super setDefaultTextAttributes:defaultTextAttributes];
   [self _updatePlaceholder];
 }
 
-- (RCTTextAttributes *)reactTextAttributes
+- (NSDictionary<NSAttributedStringKey, id> *)defaultTextAttributes
 {
-  return _reactTextAttributes;
+  return _defaultTextAttributes;
 }
 
 - (void)_updatePlaceholder
 {
-  if (self.placeholder == nil) {
-    return;
-  }
-
-  self.attributedPlaceholder = [[NSAttributedString alloc] initWithString:self.placeholder
-                                                               attributes:[self placeholderEffectiveTextAttributes]];
+  self.attributedPlaceholder = [[NSAttributedString alloc] initWithString:self.placeholder ?: @""
+                                                               attributes:[self _placeholderTextAttributes]];
 }
 
 - (BOOL)isEditable
@@ -119,24 +111,17 @@
 
 #pragma mark - Placeholder
 
-- (NSDictionary<NSAttributedStringKey, id> *)placeholderEffectiveTextAttributes
+- (NSDictionary<NSAttributedStringKey, id> *)_placeholderTextAttributes
 {
-  NSMutableDictionary<NSAttributedStringKey, id> *effectiveTextAttributes = [NSMutableDictionary dictionary];
-  
-  if (_placeholderColor) {
-    effectiveTextAttributes[NSForegroundColorAttributeName] = _placeholderColor;
+  NSMutableDictionary<NSAttributedStringKey, id> *textAttributes = [_defaultTextAttributes mutableCopy] ?: [NSMutableDictionary new];
+
+  if (self.placeholderColor) {
+    [textAttributes setValue:self.placeholderColor forKey:NSForegroundColorAttributeName];
+  } else {
+    [textAttributes removeObjectForKey:NSForegroundColorAttributeName];
   }
-  // Kerning
-  if (!isnan(_reactTextAttributes.letterSpacing)) {
-    effectiveTextAttributes[NSKernAttributeName] = @(_reactTextAttributes.letterSpacing);
-  }
-  
-  NSParagraphStyle *paragraphStyle = [_reactTextAttributes effectiveParagraphStyle];
-  if (paragraphStyle) {
-    effectiveTextAttributes[NSParagraphStyleAttributeName] = paragraphStyle;
-  }
-  
-  return [effectiveTextAttributes copy];
+
+  return textAttributes;
 }
 
 #pragma mark - Context Menu
@@ -161,7 +146,6 @@
   return [super caretRectForPosition:position];
 }
 
-
 #pragma mark - Positioning Overrides
 
 - (CGRect)textRectForBounds:(CGRect)bounds
@@ -215,7 +199,7 @@
 {
   // Note: `placeholder` defines intrinsic size for `<TextInput>`.
   NSString *text = self.placeholder ?: @"";
-  CGSize size = [text sizeWithAttributes:[self placeholderEffectiveTextAttributes]];
+  CGSize size = [text sizeWithAttributes:[self _placeholderTextAttributes]];
   size = CGSizeMake(RCTCeilPixelValue(size.width), RCTCeilPixelValue(size.height));
   size.width += _textContainerInset.left + _textContainerInset.right;
   size.height += _textContainerInset.top + _textContainerInset.bottom;