Introduce a wrapper class to handle text node in TextIterator

third_party/WebKit/Source/core/editing/iterators/TextIterator.h

 /*
  * Copyright (C) 2004, 2006, 2009 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 31 matching lines @@
 class LayoutText;
 class LayoutTextFragment;
 
 CORE_EXPORT String
 PlainText(const EphemeralRange&,
           const TextIteratorBehavior& = TextIteratorBehavior());
 
 String PlainText(const EphemeralRangeInFlatTree&,
                  const TextIteratorBehavior& = TextIteratorBehavior());
 
+// TODO(xiaochengh): Move the class to dedicated files.
+// TextIteratorTextNodeHandler extracts plain text from a text node by calling
+// HandleTextNode() function. It should be used only by TextIterator.
+class TextIteratorTextNodeHandler {
+  STACK_ALLOCATED();
+
+ public:
+  TextIteratorTextNodeHandler(const TextIteratorBehavior&,
+                              TextIteratorTextState&);

[yosin_UTC9, 2017/05/26 01:47:25]

nit: s/TextIteratorState&/TextIterator*/

[Xiaocheng, 2017/05/26 21:56:39]

Done.

+
+  void SetBoundaries(Node* start_container,
+                     int start_offset,
+                     Node* end_container,
+                     int end_offset);
+
+  Text* GetNode() const { return text_node_; }
+
+  // Returns true if more text is emitted without traversing to the next node.
+  bool HandleRemainingTextRuns();
+
+  // Returns true if a leading white space is emitted before a replaced element.
+  bool FixLeadingWhiteSpaceForReplacedElement(Node*);
+
+  void ResetCollapsedWhiteSpaceFixup();
+
+  // TODO(xiaochengh): Make the return type |void|. The current return value is
+  // not very meaningful.
+  bool HandleTextNode(Text*);
+
+ private:
+  void HandlePreFormattedTextNode();
+  void HandleTextBox();
+  void HandleTextNodeFirstLetter(LayoutTextFragment*);
+  bool ShouldHandleFirstLetter(const LayoutText&) const;
+  bool ShouldProceedToRemainingText() const;
+  void ProceedToRemainingText();
+  size_t RestoreCollapsedTrailingSpace(InlineTextBox* next_text_box,
+                                       size_t subrun_end);
+
+  // Used when the visibility of the style should not affect text gathering.
+  bool IgnoresStyleVisibility() const {
+    return behavior_.IgnoresStyleVisibility();
+  }
+
+  void SpliceBuffer(UChar,
+                    Node* text_node,
+                    Node* offset_base_node,
+                    int text_start_offset,
+                    int text_end_offset);
+  void EmitText(Node* text_node,
+                LayoutText* layout_object,
+                int text_start_offset,
+                int text_end_offset);
+
+  // The range.
+  Member<Node> start_container_;
+  int start_offset_ = 0;
+  Member<Node> end_container_;
+  int end_offset_ = 0;
+
+  // The current text node and offset, from which text is being emitted.
+  Member<Text> text_node_;
+  int offset_ = 0;
+
+  InlineTextBox* text_box_ = nullptr;
+
+  // Remember if we are in the middle of handling a pre-formatted text node.
+  bool needs_handle_pre_formatted_text_node_ = false;
+  // Used when deciding text fragment created by :first-letter should be looked
+  // into.
+  bool handled_first_letter_ = false;
+  // Used when iteration over :first-letter text to save pointer to
+  // remaining text box.
+  InlineTextBox* remaining_text_box_ = nullptr;
+  // Used to point to LayoutText object for :first-letter.
+  LayoutText* first_letter_text_ = nullptr;
+
+  // Used to do the whitespace collapsing logic.
+  bool last_text_node_ended_with_collapsed_space_ = false;
+
+  // Used when text boxes are out of order (Hebrew/Arabic w/ embeded LTR text)
+  Vector<InlineTextBox*> sorted_text_boxes_;
+  size_t sorted_text_boxes_position_ = 0;
+
+  const TextIteratorBehavior behavior_;
+
+  // Contains state of emitted text.
+  TextIteratorTextState& text_state_;
+};

[yosin_UTC9, 2017/05/26 01:47:25]

nit: We should have |DISALLOW_COPY_AND_ASSIGN(...)|.

[Xiaocheng, 2017/05/26 21:56:39]

Done.

+
 // Iterates through the DOM range, returning all the text, and 0-length
 // boundaries at points where replaced elements break up the text flow.  The
 // text comes back in chunks so as to optimize for performance of the iteration.
 
 template <typename Strategy>
 class CORE_TEMPLATE_CLASS_EXPORT TextIteratorAlgorithm {
   STACK_ALLOCATED();
 
  public:
   // [start, end] indicates the document range that the iteration should take
@@ skipping 72 matching lines @@
   bool ShouldRepresentNodeOffsetZero();
   bool ShouldEmitSpaceBeforeAndAfterNode(Node*);
   void RepresentNodeOffsetZero();
 
   // Return true if the iteration progress should advance to |kHandledNode|
   // after calling a |HandleXXX| function.
   // TODO(xiaochengh): The meaning of the return values is unclear, and they do
   // not always clearly control the iteration progress. Should consider removing
   // the return values and control the iteration in a cleaner way.
   bool HandleTextNode();
-  void HandlePreFormattedTextNode();
   bool HandleReplacedElement();
   bool HandleNonTextNode();
-
-  void HandleTextBox();
-  void HandleTextNodeFirstLetter(LayoutTextFragment*);
-  bool ShouldHandleFirstLetter(const LayoutText&) const;
-  bool ShouldProceedToRemainingText() const;
-  void ProceedToRemainingText();
-  void ResetCollapsedWhiteSpaceFixup();
-
-  // Returns true if more text is emitted without traversing to the next node.
-  bool HandleRemainingTextRuns();
-
-  // Returns true if a leading white space is emitted before a replaced element.
-  bool FixLeadingWhiteSpaceForReplacedElement(Node* parent);
-
   void SpliceBuffer(UChar,
                     Node* text_node,
                     Node* offset_base_node,
                     int text_start_offset,
                     int text_end_offset);
-  void EmitText(Node* text_node,
-                LayoutText* layout_object,
-                int text_start_offset,
-                int text_end_offset);
-  size_t RestoreCollapsedTrailingSpace(InlineTextBox* next_text_box,
-                                       size_t subrun_end);
 
   // Used by selection preservation code. There should be one character emitted
   // between every VisiblePosition in the Range used to create the TextIterator.
   // FIXME <rdar://problem/6028818>: This functionality should eventually be
   // phased out when we rewrite moveParagraphs to not clone/destroy moved
   // content.
   bool EmitsCharactersBetweenAllVisiblePositions() const {
     return behavior_.EmitsCharactersBetweenAllVisiblePositions();
   }
 
@@ skipping 34 matching lines @@
 
   // Append code units with offset range [position, position + copyLength)
   // to the output buffer.
   void CopyCodeUnitsTo(ForwardsTextBuffer* output,
                        int position,
                        int copy_length) const;
 
   // Current position, not necessarily of the text being returned, but position
   // as we walk through the DOM tree.
   Member<Node> node_;
-  int offset_;
   IterationProgress iteration_progress_;
   FullyClippedStateStackAlgorithm<Strategy> fully_clipped_stack_;
   int shadow_depth_;
 
   // The range.
   Member<Node> start_container_;
   int start_offset_;
   Member<Node> end_container_;
   int end_offset_;
   // |m_endNode| stores |Strategy::childAt(*m_endContainer, m_endOffset - 1)|,
   // if it exists, or |nullptr| otherwise.
   Member<Node> end_node_;
   Member<Node> past_end_node_;
 
-  // The current text node, from which text is being emitted.
-  Member<Text> text_node_;
-
   // Used when there is still some pending text from the current node; when
   // these are false and 0, we go back to normal iterating.
   bool needs_another_newline_;
-  InlineTextBox* text_box_;
-  // Used when iteration over :first-letter text to save pointer to
-  // remaining text box.
-  InlineTextBox* remaining_text_box_;
-  // Used to point to LayoutText object for :first-letter.
-  LayoutText* first_letter_text_;
 
-  // Used to do the whitespace collapsing logic.
   Member<Text> last_text_node_;
-  bool last_text_node_ended_with_collapsed_space_;
-
-  // Used when text boxes are out of order (Hebrew/Arabic w/ embeded LTR text)
-  Vector<InlineTextBox*> sorted_text_boxes_;
-  size_t sorted_text_boxes_position_;
 
   const TextIteratorBehavior behavior_;
 
-  // Remember if we are in the middle of handling a pre-formatted text node.
-  bool needs_handle_pre_formatted_text_node_;
-  // Used when deciding text fragment created by :first-letter should be looked
-  // into.
-  bool handled_first_letter_;
   // Used when stopsOnFormControls() is true to determine if the iterator should
   // keep advancing.
   bool should_stop_;
   // Used for use counter |InnerTextWithShadowTree| and
   // |SelectionToStringWithShadowTree|, we should not use other purpose.
   bool handle_shadow_root_;
 
   // Contains state of emitted text.
   TextIteratorTextState text_state_;
+
+  // Helper for extracting text content from text nodes.
+  TextIteratorTextNodeHandler text_node_handler_;

[yosin_UTC9, 2017/05/26 01:47:25]

It is better to use |TextIteratorTextNodeHandler*| to move class declaration
into ".cpp" file
to hide implementation details.

In addition of this, we'll use pointer for switching legacy and ng.

[Xiaocheng, 2017/05/26 21:56:39]

Added a TODO for it.

I don't want to handle memory issues now.

 };
 
 extern template class CORE_EXTERN_TEMPLATE_EXPORT
     TextIteratorAlgorithm<EditingStrategy>;
 extern template class CORE_EXTERN_TEMPLATE_EXPORT
     TextIteratorAlgorithm<EditingInFlatTreeStrategy>;
 
 using TextIterator = TextIteratorAlgorithm<EditingStrategy>;
 using TextIteratorInFlatTree = TextIteratorAlgorithm<EditingInFlatTreeStrategy>;
 
 }  // namespace blink
 
 #endif  // TextIterator_h