Use NSTextStorageDelegate instead of method swizzling

apple/MarkdownCommitHook.mm

@@ -170,8 +170,8 @@
             }
 
             // apply markdown
-            auto newString = [utils parseMarkdown:nsAttributedString
-                                   withAttributes:defaultNSTextAttributes];
+            NSMutableAttributedString *newString = [nsAttributedString mutableCopy];
+            [utils applyFormatting:newString withDefaultTextAttributes:defaultNSTextAttributes];
 
             // create a clone of the old TextInputState and update the
             // attributed string box to point to the string with markdown
@@ -217,8 +217,8 @@
                     stateData.attributedStringBox);
 
             // apply markdown
-            auto newString = [utils parseMarkdown:nsAttributedString
-                                   withAttributes:defaultNSTextAttributes];
+            NSMutableAttributedString *newString = [nsAttributedString mutableCopy];
+            [utils applyFormatting:newString withDefaultTextAttributes:defaultNSTextAttributes];
 
             // create a clone of the old TextInputState and update the
             // attributed string box to point to the string with markdown

apple/MarkdownTextInputDecoratorView.mm

@@ -1,29 +1,18 @@
 #import <React/RCTUITextField.h>
+#import <React/RCTUITextView.h>
+#import <React/RCTTextInputComponentView.h>
 #import "react_native_assert.h"
 
 #import <RNLiveMarkdown/MarkdownLayoutManager.h>
 #import <RNLiveMarkdown/MarkdownTextInputDecoratorView.h>
-#import <RNLiveMarkdown/RCTBackedTextFieldDelegateAdapter+Markdown.h>
-#import <RNLiveMarkdown/RCTUITextView+Markdown.h>
-
-#ifdef RCT_NEW_ARCH_ENABLED
-#import <RNLiveMarkdown/RCTTextInputComponentView+Markdown.h>
-#else
-#import <RNLiveMarkdown/RCTBaseTextInputView+Markdown.h>
-#endif /* RCT_NEW_ARCH_ENABLED */
+#import <RNLiveMarkdown/MarkdownTextStorageDelegate.h>
 
 #import <objc/runtime.h>
 
 @implementation MarkdownTextInputDecoratorView {
   RCTMarkdownUtils *_markdownUtils;
   RCTMarkdownStyle *_markdownStyle;
-#ifdef RCT_NEW_ARCH_ENABLED
-  __weak RCTTextInputComponentView *_textInput;
-#else
-  __weak RCTBaseTextInputView *_textInput;
-#endif /* RCT_NEW_ARCH_ENABLED */
-  __weak UIView<RCTBackedTextInputViewProtocol> *_backedTextInputView;
-  __weak RCTBackedTextFieldDelegateAdapter *_adapter;
+  MarkdownTextStorageDelegate *_markdownTextStorageDelegate;
   __weak RCTUITextView *_textView;
 }
 
@@ -51,26 +40,33 @@ - (void)didMoveToWindow {
 
 #ifdef RCT_NEW_ARCH_ENABLED
   react_native_assert([view isKindOfClass:[RCTTextInputComponentView class]] && "Previous sibling component is not an instance of RCTTextInputComponentView.");
-  _textInput = (RCTTextInputComponentView *)view;
-  _backedTextInputView = [_textInput valueForKey:@"_backedTextInputView"];
+  RCTTextInputComponentView *textInputComponentView = (RCTTextInputComponentView *)view;
+  UIView<RCTBackedTextInputViewProtocol> *backedTextInputView = [textInputComponentView valueForKey:@"_backedTextInputView"];
 #else
-  react_native_assert([view isKindOfClass:[RCTBaseTextInputView class]] && "Previous sibling component is not an instance of RCTBaseTextInputView.");
-  _textInput = (RCTBaseTextInputView *)view;
-  _backedTextInputView = _textInput.backedTextInputView;
+  // TODO: implement on Paper
+  react_native_assert(false && "Not implemented on Paper yet");
 #endif /* RCT_NEW_ARCH_ENABLED */
 
   _markdownUtils = [[RCTMarkdownUtils alloc] init];
   react_native_assert(_markdownStyle != nil);
   [_markdownUtils setMarkdownStyle:_markdownStyle];
 
-  [_textInput setMarkdownUtils:_markdownUtils];
-  if ([_backedTextInputView isKindOfClass:[RCTUITextField class]]) {
-    RCTUITextField *textField = (RCTUITextField *)_backedTextInputView;
-    _adapter = [textField valueForKey:@"textInputDelegateAdapter"];
-    [_adapter setMarkdownUtils:_markdownUtils];
-  } else if ([_backedTextInputView isKindOfClass:[RCTUITextView class]]) {
-    _textView = (RCTUITextView *)_backedTextInputView;
-    [_textView setMarkdownUtils:_markdownUtils];
+  if ([backedTextInputView isKindOfClass:[RCTUITextField class]]) {
+    // TODO: implement for singleline input
+    react_native_assert(false && "Not implemented for singleline input yet");
+  } else if ([backedTextInputView isKindOfClass:[RCTUITextView class]]) {
+    _textView = (RCTUITextView *)backedTextInputView;
+
+    _markdownTextStorageDelegate = [[MarkdownTextStorageDelegate alloc] init];
+    _markdownTextStorageDelegate.markdownUtils = _markdownUtils;
+    _markdownTextStorageDelegate.textView = _textView;
+
+    // register delegate for future edits
+    _textView.textStorage.delegate = _markdownTextStorageDelegate;
+
+    // format initial value
+    [_textView.textStorage setAttributedString:_textView.attributedText];
+
     NSLayoutManager *layoutManager = _textView.layoutManager; // switching to TextKit 1 compatibility mode
 
     // Correct content height in TextKit 1 compatibility mode. (See https://github.com/Expensify/App/issues/41567)
@@ -90,14 +86,9 @@ - (void)didMoveToWindow {
 
 - (void)willMoveToWindow:(UIWindow *)newWindow
 {
-  if (_textInput != nil) {
-    [_textInput setMarkdownUtils:nil];
-  }
-  if (_adapter != nil) {
-    [_adapter setMarkdownUtils:nil];
-  }
   if (_textView != nil) {
-    [_textView setMarkdownUtils:nil];
+    _textView.textStorage.delegate = nil;
+
     if (_textView.layoutManager != nil && [object_getClass(_textView.layoutManager) isEqual:[MarkdownLayoutManager class]]) {
       [_textView.layoutManager setValue:nil forKey:@"markdownUtils"];
       object_setClass(_textView.layoutManager, [NSLayoutManager class]);
@@ -110,17 +101,8 @@ - (void)setMarkdownStyle:(RCTMarkdownStyle *)markdownStyle
   _markdownStyle = markdownStyle;
   [_markdownUtils setMarkdownStyle:markdownStyle];
 
-  if (_textView != nil) {
-    // We want to use `textStorage` for applying markdown when possible. Currently it's only available for UITextView
-    [_textView textDidChange];
-  } else {
-    // apply new styles
-#ifdef RCT_NEW_ARCH_ENABLED
-    [_textInput _setAttributedString:_backedTextInputView.attributedText];
-#else
-    [_textInput setAttributedText:_textInput.attributedText];
-#endif /* RCT_NEW_ARCH_ENABLED */
-  }
+  // trigger reformatting
+  [_textView.textStorage setAttributedString:_textView.attributedText];
 }
 
 @end

apple/MarkdownTextStorageDelegate.h

@@ -0,0 +1,15 @@
+#import <UIKit/UIKit.h>
+#import <React/RCTUITextView.h>
+#import <RNLiveMarkdown/RCTMarkdownUtils.h>
+
+NS_ASSUME_NONNULL_BEGIN
+
+@interface MarkdownTextStorageDelegate : NSObject <NSTextStorageDelegate>
+
+@property(nonatomic, nullable) RCTMarkdownUtils *markdownUtils;
+
+@property(nonatomic, nullable, strong) RCTUITextView *textView;
+
+@end
+
+NS_ASSUME_NONNULL_END

apple/MarkdownTextStorageDelegate.mm

@@ -0,0 +1,15 @@
+#import <RNLiveMarkdown/MarkdownTextStorageDelegate.h>
+
+@implementation MarkdownTextStorageDelegate
+
+- (void)textStorage:(NSTextStorage *)textStorage didProcessEditing:(NSTextStorageEditActions)editedMask range:(NSRange)editedRange changeInLength:(NSInteger)delta {
+  react_native_assert(_markdownUtils != nil);
+  react_native_assert(_textView != nil);
+  react_native_assert(_textView.defaultTextAttributes != nil);
+
+  [_markdownUtils applyFormatting:textStorage withDefaultTextAttributes:_textView.defaultTextAttributes];
+
+  // TODO: fix cursor position when adding newline after a blockquote (probably not here though)
+}
+
+@end

apple/RCTMarkdownUtils.h

@@ -8,7 +8,7 @@ NS_ASSUME_NONNULL_BEGIN
 @property (nonatomic) RCTMarkdownStyle *markdownStyle;
 @property (nonatomic) NSMutableArray<NSDictionary *> *blockquoteRangesAndLevels;
 
-- (NSAttributedString *)parseMarkdown:(nullable NSAttributedString *)input withAttributes:(nullable NSDictionary<NSAttributedStringKey, id>*)attributes;
+- (void)applyFormatting:(nonnull NSMutableAttributedString *)attributedString withDefaultTextAttributes:(nonnull NSDictionary<NSAttributedStringKey,id> *)defaultTextAttributes;
 
 @end