react-native/Libraries/Text/RCTTextManager.m

/**
 * Copyright (c) 2015-present, Facebook, Inc.
 * All rights reserved.
 *
 * This source code is licensed under the BSD-style license found in the
 * LICENSE file in the root directory of this source tree. An additional grant
 * of patent rights can be found in the PATENTS file in the same directory.
 */

#import "RCTTextManager.h"

#import "Layout.h"
#import "RCTAccessibilityManager.h"
#import "RCTAssert.h"
#import "RCTConvert.h"
#import "RCTLog.h"
#import "RCTShadowRawText.h"
#import "RCTShadowText.h"
#import "RCTText.h"
#import "RCTTextView.h"
#import "UIView+React.h"

static void collectDirtyNonTextDescendants(RCTShadowText *shadowView, NSMutableArray *nonTextDescendants) {
  for (RCTShadowView *child in shadowView.reactSubviews) {
    if ([child isKindOfClass:[RCTShadowText class]]) {
      collectDirtyNonTextDescendants((RCTShadowText *)child, nonTextDescendants);
    } else if ([child isKindOfClass:[RCTShadowRawText class]]) {
      // no-op
    } else if ([child isTextDirty]) {
      [nonTextDescendants addObject:child];
    }
  }
}

@interface RCTShadowText (Private)

- (NSTextStorage *)buildTextStorageForWidth:(CGFloat)width widthMode:(css_measure_mode_t)widthMode;

@end


@implementation RCTTextManager

RCT_EXPORT_MODULE()

- (UIView *)view
{
  return [RCTText new];
}

- (RCTShadowView *)shadowView
{
  return [RCTShadowText new];
}

#pragma mark - Shadow properties

RCT_EXPORT_SHADOW_PROPERTY(color, UIColor)
RCT_EXPORT_SHADOW_PROPERTY(fontFamily, NSString)
RCT_EXPORT_SHADOW_PROPERTY(fontSize, CGFloat)
RCT_EXPORT_SHADOW_PROPERTY(fontWeight, NSString)
RCT_EXPORT_SHADOW_PROPERTY(fontStyle, NSString)
RCT_EXPORT_SHADOW_PROPERTY(isHighlighted, BOOL)
RCT_EXPORT_SHADOW_PROPERTY(letterSpacing, CGFloat)
RCT_EXPORT_SHADOW_PROPERTY(lineHeight, CGFloat)
RCT_EXPORT_SHADOW_PROPERTY(numberOfLines, NSUInteger)
RCT_EXPORT_SHADOW_PROPERTY(textAlign, NSTextAlignment)
RCT_EXPORT_SHADOW_PROPERTY(textDecorationStyle, NSUnderlineStyle)
RCT_EXPORT_SHADOW_PROPERTY(textDecorationColor, UIColor)
RCT_EXPORT_SHADOW_PROPERTY(textDecorationLine, RCTTextDecorationLineType)
RCT_EXPORT_SHADOW_PROPERTY(writingDirection, NSWritingDirection)
RCT_EXPORT_SHADOW_PROPERTY(allowFontScaling, BOOL)
RCT_EXPORT_SHADOW_PROPERTY(opacity, CGFloat)
RCT_EXPORT_SHADOW_PROPERTY(textShadowOffset, CGSize)
RCT_EXPORT_SHADOW_PROPERTY(textShadowRadius, CGFloat)
RCT_EXPORT_SHADOW_PROPERTY(textShadowColor, UIColor)

- (RCTViewManagerUIBlock)uiBlockToAmendWithShadowViewRegistry:(NSDictionary<NSNumber *, RCTShadowView *> *)shadowViewRegistry
{
  NSMutableSet *textViewTagsToUpdate = [NSMutableSet new];
  for (RCTShadowView *rootView in shadowViewRegistry.allValues) {
    if (![rootView isReactRootView]) {
      // This isn't a root view
      continue;
    }

    if (![rootView isTextDirty]) {
      // No text processing to be done
      continue;
    }

    NSMutableArray<RCTShadowView *> *queue = [NSMutableArray arrayWithObject:rootView];
    for (NSInteger i = 0; i < queue.count; i++) {
      RCTShadowView *shadowView = queue[i];
      RCTAssert([shadowView isTextDirty], @"Don't process any nodes that don't have dirty text");

      if ([shadowView isKindOfClass:[RCTShadowText class]]) {
        ((RCTShadowText *)shadowView).fontSizeMultiplier = self.bridge.accessibilityManager.multiplier;
        [(RCTShadowText *)shadowView recomputeText];
        collectDirtyNonTextDescendants((RCTShadowText *)shadowView, queue);
      } else if ([shadowView isKindOfClass:[RCTShadowRawText class]]) {
        RCTLogError(@"Raw text cannot be used outside of a <Text> tag. Not rendering string: '%@'",
                    [(RCTShadowRawText *)shadowView text]);
      } else {
        NSNumber *reactTag = shadowView.reactTag;
        // This isn't pretty, but hopefully it's temporary
        // the problem is, there's no easy way (besides the viewName)
        // to tell from the shadowView if the view is an RKTextView
        if ([shadowView.viewName hasSuffix:@"TextView"]) {
          // Add to textViewTagsToUpdate only if has a RCTShadowText subview
          for (RCTShadowView *subview in shadowView.reactSubviews) {
            if ([subview isKindOfClass:[RCTShadowText class]]) {
              [textViewTagsToUpdate addObject:reactTag];
              break;
            }
          }
        }
        for (RCTShadowView *child in [shadowView reactSubviews]) {
          if ([child isTextDirty]) {
            [queue addObject:child];
          }
        }
      }

      [shadowView setTextComputed];
    }
  }

  /**
   * NOTE: this logic is included to support rich text editing inside multiline
   * `<TextInput>` controls. It is required in order to ensure that the
   * textStorage (aka attributed string) is copied over from the RCTShadowText
   * to the RCTText view in time to be used to update the editable text content.
   */
  if (textViewTagsToUpdate.count) {

    NSMutableArray<RCTViewManagerUIBlock> *uiBlocks = [NSMutableArray new];
    for (NSNumber *reactTag in textViewTagsToUpdate) {
      RCTShadowView *shadowTextView = shadowViewRegistry[reactTag];
      RCTShadowText *shadowText;
      for (RCTShadowText *subview in shadowTextView.reactSubviews) {
        if ([subview isKindOfClass:[RCTShadowText class]]) {
          shadowText = subview;
          break;
        }
      }

      UIEdgeInsets padding = shadowText.paddingAsInsets;
      CGFloat width = shadowText.frame.size.width - (padding.left + padding.right);

      NSTextStorage *textStorage = [shadowText buildTextStorageForWidth:width widthMode:CSS_MEASURE_MODE_EXACTLY];
      [uiBlocks addObject:^(RCTUIManager *uiManager, NSDictionary<NSNumber *, RCTTextView *> *viewRegistry) {
        RCTTextView *textView = viewRegistry[reactTag];
        RCTText *text;
        for (RCTText *subview in textView.reactSubviews) {
          if ([subview isKindOfClass:[RCTText class]]) {
            text = subview;
            break;
          }
        }

        text.textStorage = textStorage;
        [textView performTextUpdate];
      }];
    }

    return ^(RCTUIManager *uiManager, NSDictionary<NSNumber *, UIView *> *viewRegistry) {
      for (RCTViewManagerUIBlock uiBlock in uiBlocks) {
        uiBlock(uiManager, viewRegistry);
      }
    };
  } else {
    return nil;
  }
}

- (RCTViewManagerUIBlock)uiBlockToAmendWithShadowView:(RCTShadowText *)shadowView
{
  NSNumber *reactTag = shadowView.reactTag;
  UIEdgeInsets padding = shadowView.paddingAsInsets;

  return ^(RCTUIManager *uiManager, NSDictionary<NSNumber *, RCTText *> *viewRegistry) {
    RCTText *text = viewRegistry[reactTag];
    text.contentInset = padding;
  };
}

@end